+++ /dev/null
-//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements a module pass that applies a variety of small
-// optimizations for calls to specific well-known function calls (e.g. runtime
-// library functions). For example, a call to the function "exit(3)" that
-// occurs within the main() function can be transformed into a simple "return 3"
-// instruction. Any optimization that takes this form (replace call to library
-// function with simpler code that provides the same result) belongs in this
-// file.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "simplify-libcalls"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Config/config.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/IPO.h"
-#include <cstring>
-using namespace llvm;
-
-/// This statistic keeps track of the total number of library calls that have
-/// been simplified regardless of which call it is.
-STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
-
-namespace {
- // Forward declarations
- class LibCallOptimization;
- class SimplifyLibCalls;
-
-/// This list is populated by the constructor for LibCallOptimization class.
-/// Therefore all subclasses are registered here at static initialization time
-/// and this list is what the SimplifyLibCalls pass uses to apply the individual
-/// optimizations to the call sites.
-/// @brief The list of optimizations deriving from LibCallOptimization
-static LibCallOptimization *OptList = 0;
-
-/// This class is the abstract base class for the set of optimizations that
-/// corresponds to one library call. The SimplifyLibCalls pass will call the
-/// ValidateCalledFunction method to ask the optimization if a given Function
-/// is the kind that the optimization can handle. If the subclass returns true,
-/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
-/// or attempt to perform, the optimization(s) for the library call. Otherwise,
-/// OptimizeCall won't be called. Subclasses are responsible for providing the
-/// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
-/// constructor. This is used to efficiently select which call instructions to
-/// optimize. The criteria for a "lib call" is "anything with well known
-/// semantics", typically a library function that is defined by an international
-/// standard. Because the semantics are well known, the optimizations can
-/// generally short-circuit actually calling the function if there's a simpler
-/// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
-/// @brief Base class for library call optimizations
-class VISIBILITY_HIDDEN LibCallOptimization {
- LibCallOptimization **Prev, *Next;
- const char *FunctionName; ///< Name of the library call we optimize
-#ifndef NDEBUG
- Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
-#endif
-public:
- /// The \p fname argument must be the name of the library function being
- /// optimized by the subclass.
- /// @brief Constructor that registers the optimization.
- LibCallOptimization(const char *FName, const char *Description)
- : FunctionName(FName) {
-
-#ifndef NDEBUG
- occurrences.construct("simplify-libcalls", Description);
-#endif
- // Register this optimizer in the list of optimizations.
- Next = OptList;
- OptList = this;
- Prev = &OptList;
- if (Next) Next->Prev = &Next;
- }
-
- /// getNext - All libcall optimizations are chained together into a list,
- /// return the next one in the list.
- LibCallOptimization *getNext() { return Next; }
-
- /// @brief Deregister from the optlist
- virtual ~LibCallOptimization() {
- *Prev = Next;
- if (Next) Next->Prev = Prev;
- }
-
- /// The implementation of this function in subclasses should determine if
- /// \p F is suitable for the optimization. This method is called by
- /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
- /// sites of such a function if that function is not suitable in the first
- /// place. If the called function is suitabe, this method should return true;
- /// false, otherwise. This function should also perform any lazy
- /// initialization that the LibCallOptimization needs to do, if its to return
- /// true. This avoids doing initialization until the optimizer is actually
- /// going to be called upon to do some optimization.
- /// @brief Determine if the function is suitable for optimization
- virtual bool ValidateCalledFunction(
- const Function* F, ///< The function that is the target of call sites
- SimplifyLibCalls& SLC ///< The pass object invoking us
- ) = 0;
-
- /// The implementations of this function in subclasses is the heart of the
- /// SimplifyLibCalls algorithm. Sublcasses of this class implement
- /// OptimizeCall to determine if (a) the conditions are right for optimizing
- /// the call and (b) to perform the optimization. If an action is taken
- /// against ci, the subclass is responsible for returning true and ensuring
- /// that ci is erased from its parent.
- /// @brief Optimize a call, if possible.
- virtual bool OptimizeCall(
- CallInst* ci, ///< The call instruction that should be optimized.
- SimplifyLibCalls& SLC ///< The pass object invoking us
- ) = 0;
-
- /// @brief Get the name of the library call being optimized
- const char *getFunctionName() const { return FunctionName; }
-
- bool ReplaceCallWith(CallInst *CI, Value *V) {
- if (!CI->use_empty())
- CI->replaceAllUsesWith(V);
- CI->eraseFromParent();
- return true;
- }
-
- /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
- void succeeded() {
-#ifndef NDEBUG
- DEBUG(++occurrences);
-#endif
- }
-};
-
-/// This class is an LLVM Pass that applies each of the LibCallOptimization
-/// instances to all the call sites in a module, relatively efficiently. The
-/// purpose of this pass is to provide optimizations for calls to well-known
-/// functions with well-known semantics, such as those in the c library. The
-/// class provides the basic infrastructure for handling runOnModule. Whenever
-/// this pass finds a function call, it asks the appropriate optimizer to
-/// validate the call (ValidateLibraryCall). If it is validated, then
-/// the OptimizeCall method is also called.
-/// @brief A ModulePass for optimizing well-known function calls.
-class VISIBILITY_HIDDEN SimplifyLibCalls : public ModulePass {
-public:
- static char ID; // Pass identification, replacement for typeid
- SimplifyLibCalls() : ModulePass((intptr_t)&ID) {}
-
- /// We need some target data for accurate signature details that are
- /// target dependent. So we require target data in our AnalysisUsage.
- /// @brief Require TargetData from AnalysisUsage.
- virtual void getAnalysisUsage(AnalysisUsage& Info) const {
- // Ask that the TargetData analysis be performed before us so we can use
- // the target data.
- Info.addRequired<TargetData>();
- }
-
- /// For this pass, process all of the function calls in the module, calling
- /// ValidateLibraryCall and OptimizeCall as appropriate.
- /// @brief Run all the lib call optimizations on a Module.
- virtual bool runOnModule(Module &M) {
- reset(M);
-
- bool result = false;
- StringMap<LibCallOptimization*> OptznMap;
- for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
- OptznMap[Optzn->getFunctionName()] = Optzn;
-
- // The call optimizations can be recursive. That is, the optimization might
- // generate a call to another function which can also be optimized. This way
- // we make the LibCallOptimization instances very specific to the case they
- // handle. It also means we need to keep running over the function calls in
- // the module until we don't get any more optimizations possible.
- bool found_optimization = false;
- do {
- found_optimization = false;
- for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
- // All the "well-known" functions are external and have external linkage
- // because they live in a runtime library somewhere and were (probably)
- // not compiled by LLVM. So, we only act on external functions that
- // have external or dllimport linkage and non-empty uses.
- if (!FI->isDeclaration() ||
- !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
- FI->use_empty())
- continue;
-
- // Get the optimization class that pertains to this function
- StringMap<LibCallOptimization*>::iterator OMI =
- OptznMap.find(FI->getName());
- if (OMI == OptznMap.end()) continue;
-
- LibCallOptimization *CO = OMI->second;
-
- // Make sure the called function is suitable for the optimization
- if (!CO->ValidateCalledFunction(FI, *this))
- continue;
-
- // Loop over each of the uses of the function
- for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
- UI != UE ; ) {
- // If the use of the function is a call instruction
- if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
- // Do the optimization on the LibCallOptimization.
- if (CO->OptimizeCall(CI, *this)) {
- ++SimplifiedLibCalls;
- found_optimization = result = true;
- CO->succeeded();
- }
- }
- }
- }
- } while (found_optimization);
-
- return result;
- }
-
- /// @brief Return the *current* module we're working on.
- Module* getModule() const { return M; }
-
- /// @brief Return the *current* target data for the module we're working on.
- TargetData* getTargetData() const { return TD; }
-
- /// @brief Return the size_t type -- syntactic shortcut
- const Type* getIntPtrType() const { return TD->getIntPtrType(); }
-
- /// @brief Return a Function* for the putchar libcall
- Constant *get_putchar() {
- if (!putchar_func)
- putchar_func =
- M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
- return putchar_func;
- }
-
- /// @brief Return a Function* for the puts libcall
- Constant *get_puts() {
- if (!puts_func)
- puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
- PointerType::getUnqual(Type::Int8Ty),
- NULL);
- return puts_func;
- }
-
- /// @brief Return a Function* for the fputc libcall
- Constant *get_fputc(const Type* FILEptr_type) {
- if (!fputc_func)
- fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
- FILEptr_type, NULL);
- return fputc_func;
- }
-
- /// @brief Return a Function* for the fputs libcall
- Constant *get_fputs(const Type* FILEptr_type) {
- if (!fputs_func)
- fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
- PointerType::getUnqual(Type::Int8Ty),
- FILEptr_type, NULL);
- return fputs_func;
- }
-
- /// @brief Return a Function* for the fwrite libcall
- Constant *get_fwrite(const Type* FILEptr_type) {
- if (!fwrite_func)
- fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
- PointerType::getUnqual(Type::Int8Ty),
- TD->getIntPtrType(),
- TD->getIntPtrType(),
- FILEptr_type, NULL);
- return fwrite_func;
- }
-
- /// @brief Return a Function* for the sqrt libcall
- Constant *get_sqrt() {
- if (!sqrt_func)
- sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
- Type::DoubleTy, NULL);
- return sqrt_func;
- }
-
- /// @brief Return a Function* for the strcpy libcall
- Constant *get_strcpy() {
- if (!strcpy_func)
- strcpy_func = M->getOrInsertFunction("strcpy",
- PointerType::getUnqual(Type::Int8Ty),
- PointerType::getUnqual(Type::Int8Ty),
- PointerType::getUnqual(Type::Int8Ty),
- NULL);
- return strcpy_func;
- }
-
- /// @brief Return a Function* for the strlen libcall
- Constant *get_strlen() {
- if (!strlen_func)
- strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
- PointerType::getUnqual(Type::Int8Ty),
- NULL);
- return strlen_func;
- }
-
- /// @brief Return a Function* for the memchr libcall
- Constant *get_memchr() {
- if (!memchr_func)
- memchr_func = M->getOrInsertFunction("memchr",
- PointerType::getUnqual(Type::Int8Ty),
- PointerType::getUnqual(Type::Int8Ty),
- Type::Int32Ty, TD->getIntPtrType(),
- NULL);
- return memchr_func;
- }
-
- /// @brief Return a Function* for the memcpy libcall
- Constant *get_memcpy() {
- if (!memcpy_func) {
- Intrinsic::ID IID = (TD->getIntPtrType() == Type::Int32Ty) ?
- Intrinsic::memcpy_i32 : Intrinsic::memcpy_i64;
- memcpy_func = Intrinsic::getDeclaration(M, IID);
- }
- return memcpy_func;
- }
-
- Constant *getUnaryFloatFunction(const char *BaseName, const Type *T = 0) {
- if (T == 0) T = Type::FloatTy;
-
- char NameBuffer[20];
- const char *Name;
- if (T == Type::DoubleTy)
- Name = BaseName; // floor
- else {
- Name = NameBuffer;
- unsigned NameLen = strlen(BaseName);
- assert(NameLen < sizeof(NameBuffer)-2 && "Buffer too small");
- memcpy(NameBuffer, BaseName, NameLen);
- if (T == Type::FloatTy)
- NameBuffer[NameLen] = 'f'; // floorf
- else
- NameBuffer[NameLen] = 'l'; // floorl
- NameBuffer[NameLen+1] = 0;
- }
-
- return M->getOrInsertFunction(Name, T, T, NULL);
- }
-
- Constant *get_floorf() { return getUnaryFloatFunction("floor"); }
- Constant *get_ceilf() { return getUnaryFloatFunction( "ceil"); }
- Constant *get_roundf() { return getUnaryFloatFunction("round"); }
- Constant *get_rintf() { return getUnaryFloatFunction( "rint"); }
- Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyint"); }
-
-
-
-private:
- /// @brief Reset our cached data for a new Module
- void reset(Module& mod) {
- M = &mod;
- TD = &getAnalysis<TargetData>();
- putchar_func = 0;
- puts_func = 0;
- fputc_func = 0;
- fputs_func = 0;
- fwrite_func = 0;
- memcpy_func = 0;
- memchr_func = 0;
- sqrt_func = 0;
- strcpy_func = 0;
- strlen_func = 0;
- }
-
-private:
- /// Caches for function pointers.
- Constant *putchar_func, *puts_func;
- Constant *fputc_func, *fputs_func, *fwrite_func;
- Constant *memcpy_func, *memchr_func;
- Constant *sqrt_func;
- Constant *strcpy_func, *strlen_func;
- Module *M; ///< Cached Module
- TargetData *TD; ///< Cached TargetData
-};
-
-char SimplifyLibCalls::ID = 0;
-// Register the pass
-RegisterPass<SimplifyLibCalls>
-X("simplify-libcalls", "Simplify well-known library calls");
-
-} // anonymous namespace
-
-// The only public symbol in this file which just instantiates the pass object
-ModulePass *llvm::createSimplifyLibCallsPass() {
- return new SimplifyLibCalls();
-}
-
-// Forward declare utility functions.
-static bool GetConstantStringInfo(Value *V, std::string &Str);
-static Value *CastToCStr(Value *V, Instruction *IP);
-static uint64_t GetStringLength(Value *V);
-
-
-// Classes below here, in the anonymous namespace, are all subclasses of the
-// LibCallOptimization class, each implementing all optimizations possible for a
-// single well-known library call. Each has a static singleton instance that
-// auto registers it into the "optlist" global above.
-namespace {
-
-/// This LibCallOptimization will find instances of a call to "exit" that occurs
-/// within the "main" function and change it to a simple "ret" instruction with
-/// the same value passed to the exit function. When this is done, it splits the
-/// basic block at the exit(3) call and deletes the call instruction.
-/// @brief Replace calls to exit in main with a simple return
-struct VISIBILITY_HIDDEN ExitInMainOptimization : public LibCallOptimization {
- ExitInMainOptimization() : LibCallOptimization("exit",
- "Number of 'exit' calls simplified") {}
-
- // Make sure the called function looks like exit (int argument, int return
- // type, external linkage, not varargs).
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
- }
-
- virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
- // To be careful, we check that the call to exit is coming from "main", that
- // main has external linkage, and the return type of main and the argument
- // to exit have the same type.
- Function *from = ci->getParent()->getParent();
- if (from->hasExternalLinkage())
- if (from->getReturnType() == ci->getOperand(1)->getType()
- && !isa<StructType>(from->getReturnType()))
- if (from->getName() == "main") {
- // Okay, time to actually do the optimization. First, get the basic
- // block of the call instruction
- BasicBlock* bb = ci->getParent();
-
- // Create a return instruction that we'll replace the call with.
- // Note that the argument of the return is the argument of the call
- // instruction.
- ReturnInst::Create(ci->getOperand(1), ci);
-
- // Split the block at the call instruction which places it in a new
- // basic block.
- bb->splitBasicBlock(ci);
-
- // The block split caused a branch instruction to be inserted into
- // the end of the original block, right after the return instruction
- // that we put there. That's not a valid block, so delete the branch
- // instruction.
- bb->getInstList().pop_back();
-
- // Now we can finally get rid of the call instruction which now lives
- // in the new basic block.
- ci->eraseFromParent();
-
- // Optimization succeeded, return true.
- return true;
- }
- // We didn't pass the criteria for this optimization so return false
- return false;
- }
-} ExitInMainOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strcat library
-/// function. The simplification is possible only if the string being
-/// concatenated is a constant array or a constant expression that results in
-/// a constant string. In this case we can replace it with strlen + llvm.memcpy
-/// of the constant string. Both of these calls are further reduced, if possible
-/// on subsequent passes.
-/// @brief Simplify the strcat library function.
-struct VISIBILITY_HIDDEN StrCatOptimization : public LibCallOptimization {
-public:
- /// @brief Default constructor
- StrCatOptimization() : LibCallOptimization("strcat",
- "Number of 'strcat' calls simplified") {}
-
-public:
-
- /// @brief Make sure that the "strcat" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 &&
- FT->getReturnType() == PointerType::getUnqual(Type::Int8Ty) &&
- FT->getParamType(0) == FT->getReturnType() &&
- FT->getParamType(1) == FT->getReturnType();
- }
-
- /// @brief Optimize the strcat library function
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // Extract some information from the instruction
- Value *Dst = CI->getOperand(1);
- Value *Src = CI->getOperand(2);
-
- // See if we can get the length of the input string.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0) return false;
- --Len; // Unbias length.
-
- // Handle the simple, do-nothing case
- if (Len == 0)
- return ReplaceCallWith(CI, Dst);
-
- // We need to find the end of the destination string. That's where the
- // memory is to be moved to. We just generate a call to strlen.
- CallInst *DstLen = CallInst::Create(SLC.get_strlen(), Dst,
- Dst->getName()+".len", CI);
-
- // Now that we have the destination's length, we must index into the
- // destination's pointer to get the actual memcpy destination (end of
- // the string .. we're concatenating).
- Dst = GetElementPtrInst::Create(Dst, DstLen, Dst->getName()+".indexed", CI);
-
- // We have enough information to now generate the memcpy call to
- // do the concatenation for us.
- Value *Vals[] = {
- Dst, Src,
- ConstantInt::get(SLC.getIntPtrType(), Len+1), // copy nul byte.
- ConstantInt::get(Type::Int32Ty, 1) // alignment
- };
- CallInst::Create(SLC.get_memcpy(), Vals, Vals + 4, "", CI);
-
- return ReplaceCallWith(CI, Dst);
- }
-} StrCatOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strchr library
-/// function. It optimizes out cases where the arguments are both constant
-/// and the result can be determined statically.
-/// @brief Simplify the strcmp library function.
-struct VISIBILITY_HIDDEN StrChrOptimization : public LibCallOptimization {
-public:
- StrChrOptimization() : LibCallOptimization("strchr",
- "Number of 'strchr' calls simplified") {}
-
- /// @brief Make sure that the "strchr" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 &&
- FT->getReturnType() == PointerType::getUnqual(Type::Int8Ty) &&
- FT->getParamType(0) == FT->getReturnType() &&
- isa<IntegerType>(FT->getParamType(1));
- }
-
- /// @brief Perform the strchr optimizations
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- Value *SrcStr = CI->getOperand(1);
- // If the second operand is not constant, see if we can compute the length
- // and turn this into memchr.
- ConstantInt *CSI = dyn_cast<ConstantInt>(CI->getOperand(2));
- if (CSI == 0) {
- uint64_t Len = GetStringLength(SrcStr);
- if (Len == 0) return false;
-
- Value *Args[3] = {
- CI->getOperand(1),
- CI->getOperand(2),
- ConstantInt::get(SLC.getIntPtrType(), Len) // include nul.
- };
- return ReplaceCallWith(CI, CallInst::Create(SLC.get_memchr(),
- Args, Args + 3,
- CI->getName(), CI));
- }
-
- // Otherwise, the character is a constant, see if the first argument is
- // a string literal. If so, we can constant fold.
- std::string Str;
- if (!GetConstantStringInfo(SrcStr, Str))
- return false;
-
- // strchr can find the nul character.
- Str += '\0';
-
- // Get the character we're looking for
- char CharValue = CSI->getSExtValue();
-
- // Compute the offset
- uint64_t i = 0;
- while (1) {
- if (i == Str.size()) // Didn't find the char. strchr returns null.
- return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
- // Did we find our match?
- if (Str[i] == CharValue)
- break;
- ++i;
- }
-
- // strchr(s+n,c) -> gep(s+n+i,c)
- // (if c is a constant integer and s is a constant string)
- Value *Idx = ConstantInt::get(Type::Int64Ty, i);
- Value *GEP = GetElementPtrInst::Create(CI->getOperand(1), Idx,
- CI->getOperand(1)->getName() +
- ".strchr", CI);
- return ReplaceCallWith(CI, GEP);
- }
-} StrChrOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strcmp library
-/// function. It optimizes out cases where one or both arguments are constant
-/// and the result can be determined statically.
-/// @brief Simplify the strcmp library function.
-struct VISIBILITY_HIDDEN StrCmpOptimization : public LibCallOptimization {
-public:
- StrCmpOptimization() : LibCallOptimization("strcmp",
- "Number of 'strcmp' calls simplified") {}
-
- /// @brief Make sure that the "strcmp" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 2 &&
- FT->getParamType(0) == FT->getParamType(1) &&
- FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty);
- }
-
- /// @brief Perform the strcmp optimization
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // First, check to see if src and destination are the same. If they are,
- // then the optimization is to replace the CallInst with a constant 0
- // because the call is a no-op.
- Value *Str1P = CI->getOperand(1);
- Value *Str2P = CI->getOperand(2);
- if (Str1P == Str2P) // strcmp(x,x) -> 0
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
-
- std::string Str1;
- if (!GetConstantStringInfo(Str1P, Str1))
- return false;
- if (Str1.empty()) {
- // strcmp("", x) -> *x
- Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
- V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
- return ReplaceCallWith(CI, V);
- }
-
- std::string Str2;
- if (!GetConstantStringInfo(Str2P, Str2))
- return false;
- if (Str2.empty()) {
- // strcmp(x,"") -> *x
- Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
- V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
- return ReplaceCallWith(CI, V);
- }
-
- // strcmp(x, y) -> cnst (if both x and y are constant strings)
- int R = strcmp(Str1.c_str(), Str2.c_str());
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
- }
-} StrCmpOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strncmp library
-/// function. It optimizes out cases where one or both arguments are constant
-/// and the result can be determined statically.
-/// @brief Simplify the strncmp library function.
-struct VISIBILITY_HIDDEN StrNCmpOptimization : public LibCallOptimization {
-public:
- StrNCmpOptimization() : LibCallOptimization("strncmp",
- "Number of 'strncmp' calls simplified") {}
-
- /// @brief Make sure that the "strncmp" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 3 &&
- FT->getParamType(0) == FT->getParamType(1) &&
- FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
- isa<IntegerType>(FT->getParamType(2));
- return false;
- }
-
- /// @brief Perform the strncmp optimization
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // First, check to see if src and destination are the same. If they are,
- // then the optimization is to replace the CallInst with a constant 0
- // because the call is a no-op.
- Value *Str1P = CI->getOperand(1);
- Value *Str2P = CI->getOperand(2);
- if (Str1P == Str2P) // strncmp(x,x, n) -> 0
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
-
- // Check the length argument, if it is Constant zero then the strings are
- // considered equal.
- uint64_t Length;
- if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
- Length = LengthArg->getZExtValue();
- else
- return false;
-
- if (Length == 0) // strncmp(x,y,0) -> 0
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
-
- std::string Str1;
- if (!GetConstantStringInfo(Str1P, Str1))
- return false;
- if (Str1.empty()) {
- // strncmp("", x, n) -> *x
- Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
- V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
- return ReplaceCallWith(CI, V);
- }
-
- std::string Str2;
- if (!GetConstantStringInfo(Str2P, Str2))
- return false;
- if (Str2.empty()) {
- // strncmp(x, "", n) -> *x
- Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
- V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
- return ReplaceCallWith(CI, V);
- }
-
- // strncmp(x, y, n) -> cnst (if both x and y are constant strings)
- int R = strncmp(Str1.c_str(), Str2.c_str(), Length);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
- }
-} StrNCmpOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strcpy library
-/// function. Two optimizations are possible:
-/// (1) If src and dest are the same and not volatile, just return dest
-/// (2) If the src is a constant then we can convert to llvm.memmove
-/// @brief Simplify the strcpy library function.
-struct VISIBILITY_HIDDEN StrCpyOptimization : public LibCallOptimization {
-public:
- StrCpyOptimization() : LibCallOptimization("strcpy",
- "Number of 'strcpy' calls simplified") {}
-
- /// @brief Make sure that the "strcpy" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 &&
- FT->getParamType(0) == FT->getParamType(1) &&
- FT->getReturnType() == FT->getParamType(0) &&
- FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty);
- }
-
- /// @brief Perform the strcpy optimization
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // First, check to see if src and destination are the same. If they are,
- // then the optimization is to replace the CallInst with the destination
- // because the call is a no-op. Note that this corresponds to the
- // degenerate strcpy(X,X) case which should have "undefined" results
- // according to the C specification. However, it occurs sometimes and
- // we optimize it as a no-op.
- Value *Dst = CI->getOperand(1);
- Value *Src = CI->getOperand(2);
- if (Dst == Src) {
- // strcpy(x, x) -> x
- return ReplaceCallWith(CI, Dst);
- }
-
- // See if we can get the length of the input string.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0) return false;
- --Len; // Unbias length.
-
- // If the constant string's length is zero we can optimize this by just
- // doing a store of 0 at the first byte of the destination.
- if (Len == 0) {
- new StoreInst(ConstantInt::get(Type::Int8Ty, 0), Dst, CI);
- return ReplaceCallWith(CI, Dst);
- }
-
- // We have enough information to now generate the memcpy call to
- // do the concatenation for us.
- Value *MemcpyOps[] = {
- Dst, Src,
- ConstantInt::get(SLC.getIntPtrType(), Len+1),// Length including nul byte.
- ConstantInt::get(Type::Int32Ty, 1) // alignment
- };
- CallInst::Create(SLC.get_memcpy(), MemcpyOps, MemcpyOps + 4, "", CI);
-
- return ReplaceCallWith(CI, Dst);
- }
-} StrCpyOptimizer;
-
-/// This LibCallOptimization will simplify a call to the strlen library
-/// function by replacing it with a constant value if the string provided to
-/// it is a constant array.
-/// @brief Simplify the strlen library function.
-struct VISIBILITY_HIDDEN StrLenOptimization : public LibCallOptimization {
- StrLenOptimization() : LibCallOptimization("strlen",
- "Number of 'strlen' calls simplified") {}
-
- /// @brief Make sure that the "strlen" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 1 &&
- FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
- isa<IntegerType>(FT->getReturnType());
- }
-
- /// @brief Perform the strlen optimization
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // Make sure we're dealing with an sbyte* here.
- Value *Src = CI->getOperand(1);
-
- // Does the call to strlen have exactly one use?
- if (CI->hasOneUse()) {
- // Is that single use a icmp operator?
- if (ICmpInst *Cmp = dyn_cast<ICmpInst>(CI->use_back()))
- // Is it compared against a constant integer?
- if (ConstantInt *Cst = dyn_cast<ConstantInt>(Cmp->getOperand(1))) {
- // If its compared against length 0 with == or !=
- if (Cst->getZExtValue() == 0 && Cmp->isEquality()) {
- // strlen(x) != 0 -> *x != 0
- // strlen(x) == 0 -> *x == 0
- Value *V = new LoadInst(Src, Src->getName()+".first", CI);
- V = new ICmpInst(Cmp->getPredicate(), V,
- ConstantInt::get(Type::Int8Ty, 0),
- Cmp->getName()+".strlen", CI);
- Cmp->replaceAllUsesWith(V);
- Cmp->eraseFromParent();
- return ReplaceCallWith(CI, 0); // no uses.
- }
- }
- }
-
- // Get the length of the constant string operand
- // strlen("xyz") -> 3 (for example)
- if (uint64_t Len = GetStringLength(Src))
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), Len-1));
- return false;
- }
-} StrLenOptimizer;
-
-/// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
-/// is equal or not-equal to zero.
-static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI) {
- if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
- if (IC->isEquality())
- if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
- if (C->isNullValue())
- continue;
- // Unknown instruction.
- return false;
- }
- return true;
-}
-
-/// This memcmpOptimization will simplify a call to the memcmp library
-/// function.
-struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
- /// @brief Default Constructor
- memcmpOptimization()
- : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
-
- /// @brief Make sure that the "memcmp" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
- Function::const_arg_iterator AI = F->arg_begin();
- if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
- if (!isa<PointerType>((++AI)->getType())) return false;
- if (!(++AI)->getType()->isInteger()) return false;
- if (!F->getReturnType()->isInteger()) return false;
- return true;
- }
-
- /// Because of alignment and instruction information that we don't have, we
- /// leave the bulk of this to the code generators.
- ///
- /// Note that we could do much more if we could force alignment on otherwise
- /// small aligned allocas, or if we could indicate that loads have a small
- /// alignment.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
- Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
-
- // If the two operands are the same, return zero.
- if (LHS == RHS) {
- // memcmp(s,s,x) -> 0
- return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
- }
-
- // Make sure we have a constant length.
- ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
- if (!LenC) return false;
- uint64_t Len = LenC->getZExtValue();
-
- // If the length is zero, this returns 0.
- switch (Len) {
- case 0:
- // memcmp(s1,s2,0) -> 0
- return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
- case 1: {
- // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
- const Type *UCharPtr = PointerType::getUnqual(Type::Int8Ty);
- CastInst *Op1Cast = CastInst::create(
- Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
- CastInst *Op2Cast = CastInst::create(
- Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
- Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
- Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
- Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
- if (RV->getType() != CI->getType())
- RV = CastInst::createIntegerCast(RV, CI->getType(), false,
- RV->getName(), CI);
- return ReplaceCallWith(CI, RV);
- }
- case 2:
- if (IsOnlyUsedInEqualsZeroComparison(CI)) {
- // TODO: IF both are aligned, use a short load/compare.
-
- // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
- const Type *UCharPtr = PointerType::getUnqual(Type::Int8Ty);
- CastInst *Op1Cast = CastInst::create(
- Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
- CastInst *Op2Cast = CastInst::create(
- Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
- Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
- Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
- Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
- CI->getName()+".d1", CI);
- Constant *One = ConstantInt::get(Type::Int32Ty, 1);
- Value *G1 = GetElementPtrInst::Create(Op1Cast, One, "next1v", CI);
- Value *G2 = GetElementPtrInst::Create(Op2Cast, One, "next2v", CI);
- Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
- Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
- Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
- CI->getName()+".d1", CI);
- Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
- if (Or->getType() != CI->getType())
- Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
- Or->getName(), CI);
- return ReplaceCallWith(CI, Or);
- }
- break;
- default:
- break;
- }
-
- return false;
- }
-} memcmpOptimizer;
-
-/// This LibCallOptimization will simplify a call to the memcpy library
-/// function. It simply converts them into calls to llvm.memcpy.*;
-/// the resulting call should be optimized later.
-/// @brief Simplify the memcpy library function.
-struct VISIBILITY_HIDDEN MemCpyOptimization : public LibCallOptimization {
-public:
- MemCpyOptimization() : LibCallOptimization("memcpy",
- "Number of 'memcpy' calls simplified") {}
-
- /// @brief Make sure that the "memcpy" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- const Type* voidPtr = PointerType::getUnqual(Type::Int8Ty);
- return FT->getReturnType() == voidPtr && FT->getNumParams() == 3 &&
- FT->getParamType(0) == voidPtr &&
- FT->getParamType(1) == voidPtr &&
- FT->getParamType(2) == SLC.getIntPtrType();
- }
-
- /// @brief Perform the memcpy optimization
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- Value *MemcpyOps[] = {
- CI->getOperand(1), CI->getOperand(2), CI->getOperand(3),
- ConstantInt::get(Type::Int32Ty, 1) // align = 1 always.
- };
- CallInst::Create(SLC.get_memcpy(), MemcpyOps, MemcpyOps + 4, "", CI);
- // memcpy always returns the destination
- return ReplaceCallWith(CI, CI->getOperand(1));
- }
-} MemCpyOptimizer;
-
-/// This LibCallOptimization will simplify a call to the memcpy library
-/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
-/// bytes depending on the length of the string and the alignment. Additional
-/// optimizations are possible in code generation (sequence of immediate store)
-/// @brief Simplify the memcpy library function.
-struct VISIBILITY_HIDDEN LLVMMemCpyMoveOptzn : public LibCallOptimization {
- LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
- : LibCallOptimization(fname, desc) {}
-
- /// @brief Make sure that the "memcpy" function has the right prototype
- virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
- // Just make sure this has 4 arguments per LLVM spec.
- return (f->arg_size() == 4);
- }
-
- /// Because of alignment and instruction information that we don't have, we
- /// leave the bulk of this to the code generators. The optimization here just
- /// deals with a few degenerate cases where the length of the string and the
- /// alignment match the sizes of our intrinsic types so we can do a load and
- /// store instead of the memcpy call.
- /// @brief Perform the memcpy optimization.
- virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
- // Make sure we have constant int values to work with
- ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
- if (!LEN)
- return false;
- ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
- if (!ALIGN)
- return false;
-
- // If the length is larger than the alignment, we can't optimize
- uint64_t len = LEN->getZExtValue();
- uint64_t alignment = ALIGN->getZExtValue();
- if (alignment == 0)
- alignment = 1; // Alignment 0 is identity for alignment 1
- if (len > alignment)
- return false;
-
- // Get the type we will cast to, based on size of the string
- Value* dest = ci->getOperand(1);
- Value* src = ci->getOperand(2);
- const Type* castType = 0;
- switch (len) {
- case 0:
- // memcpy(d,s,0,a) -> d
- return ReplaceCallWith(ci, 0);
- case 1: castType = Type::Int8Ty; break;
- case 2: castType = Type::Int16Ty; break;
- case 4: castType = Type::Int32Ty; break;
- case 8: castType = Type::Int64Ty; break;
- default:
- return false;
- }
-
- // Cast source and dest to the right sized primitive and then load/store
- CastInst* SrcCast = CastInst::create(Instruction::BitCast,
- src, PointerType::getUnqual(castType), src->getName()+".cast", ci);
- CastInst* DestCast = CastInst::create(Instruction::BitCast,
- dest, PointerType::getUnqual(castType),dest->getName()+".cast", ci);
- LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
- new StoreInst(LI, DestCast, ci);
- return ReplaceCallWith(ci, 0);
- }
-};
-
-/// This LibCallOptimization will simplify a call to the memcpy/memmove library
-/// functions.
-LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
- "Number of 'llvm.memcpy' calls simplified");
-LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
- "Number of 'llvm.memcpy' calls simplified");
-LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
- "Number of 'llvm.memmove' calls simplified");
-LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
- "Number of 'llvm.memmove' calls simplified");
-
-/// This LibCallOptimization will simplify a call to the memset library
-/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
-/// bytes depending on the length argument.
-struct VISIBILITY_HIDDEN LLVMMemSetOptimization : public LibCallOptimization {
- /// @brief Default Constructor
- LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
- "Number of 'llvm.memset' calls simplified") {}
-
- /// @brief Make sure that the "memset" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
- // Just make sure this has 3 arguments per LLVM spec.
- return F->arg_size() == 4;
- }
-
- /// Because of alignment and instruction information that we don't have, we
- /// leave the bulk of this to the code generators. The optimization here just
- /// deals with a few degenerate cases where the length parameter is constant
- /// and the alignment matches the sizes of our intrinsic types so we can do
- /// store instead of the memcpy call. Other calls are transformed into the
- /// llvm.memset intrinsic.
- /// @brief Perform the memset optimization.
- virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
- // Make sure we have constant int values to work with
- ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
- if (!LEN)
- return false;
- ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
- if (!ALIGN)
- return false;
-
- // Extract the length and alignment
- uint64_t len = LEN->getZExtValue();
- uint64_t alignment = ALIGN->getZExtValue();
-
- // Alignment 0 is identity for alignment 1
- if (alignment == 0)
- alignment = 1;
-
- // If the length is zero, this is a no-op
- if (len == 0) {
- // memset(d,c,0,a) -> noop
- return ReplaceCallWith(ci, 0);
- }
-
- // If the length is larger than the alignment, we can't optimize
- if (len > alignment)
- return false;
-
- // Make sure we have a constant ubyte to work with so we can extract
- // the value to be filled.
- ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
- if (!FILL)
- return false;
- if (FILL->getType() != Type::Int8Ty)
- return false;
-
- // memset(s,c,n) -> store s, c (for n=1,2,4,8)
-
- // Extract the fill character
- uint64_t fill_char = FILL->getZExtValue();
- uint64_t fill_value = fill_char;
-
- // Get the type we will cast to, based on size of memory area to fill, and
- // and the value we will store there.
- Value* dest = ci->getOperand(1);
- const Type* castType = 0;
- switch (len) {
- case 1:
- castType = Type::Int8Ty;
- break;
- case 2:
- castType = Type::Int16Ty;
- fill_value |= fill_char << 8;
- break;
- case 4:
- castType = Type::Int32Ty;
- fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
- break;
- case 8:
- castType = Type::Int64Ty;
- fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
- fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
- fill_value |= fill_char << 56;
- break;
- default:
- return false;
- }
-
- // Cast dest to the right sized primitive and then load/store
- CastInst* DestCast = new BitCastInst(dest, PointerType::getUnqual(castType),
- dest->getName()+".cast", ci);
- new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
- return ReplaceCallWith(ci, 0);
- }
-};
-
-LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
-LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
-
-
-/// This LibCallOptimization will simplify calls to the "pow" library
-/// function. It looks for cases where the result of pow is well known and
-/// substitutes the appropriate value.
-/// @brief Simplify the pow library function.
-struct VISIBILITY_HIDDEN PowOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- PowOptimization(const char *Name) : LibCallOptimization(Name,
- "Number of 'pow' calls simplified") {}
-
- /// @brief Make sure that the "pow" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- // Just make sure this has 2 arguments of the same FP type, which match the
- // result type.
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 &&
- FT->getParamType(0) == FT->getParamType(1) &&
- FT->getParamType(0) == FT->getReturnType() &&
- FT->getParamType(0)->isFloatingPoint();
- }
-
- /// @brief Perform the pow optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- Value *Op1 = CI->getOperand(1);
- Value *Op2 = CI->getOperand(2);
- if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
- if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
- return ReplaceCallWith(CI, Op1C);
- if (Op1C->isExactlyValue(2.0)) {// pow(2.0, x) -> exp2(x)
- Value *Exp2 = SLC.getUnaryFloatFunction("exp2", CI->getType());
- Value *Res = CallInst::Create(Exp2, Op2, CI->getName()+"exp2", CI);
- return ReplaceCallWith(CI, Res);
- }
- }
-
- ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
- if (Op2C == 0) return false;
-
- if (Op2C->getValueAPF().isZero()) {
- // pow(x, 0.0) -> 1.0
- return ReplaceCallWith(CI, ConstantFP::get(CI->getType(), 1.0));
- } else if (Op2C->isExactlyValue(0.5)) {
- // FIXME: This is not safe for -0.0 and -inf. This can only be done when
- // 'unsafe' math optimizations are allowed.
- // x pow(x, 0.5) sqrt(x)
- // ---------------------------------------------
- // -0.0 +0.0 -0.0
- // -inf +inf NaN
-#if 0
- // pow(x, 0.5) -> sqrt(x)
- Value *Sqrt = CallInst::Create(SLC.get_sqrt(), Op1, "sqrt", CI);
- return ReplaceCallWith(CI, Sqrt);
-#endif
- } else if (Op2C->isExactlyValue(1.0)) {
- // pow(x, 1.0) -> x
- return ReplaceCallWith(CI, Op1);
- } else if (Op2C->isExactlyValue(2.0)) {
- // pow(x, 2.0) -> x*x
- Value *Sq = BinaryOperator::createMul(Op1, Op1, "pow2", CI);
- return ReplaceCallWith(CI, Sq);
- } else if (Op2C->isExactlyValue(-1.0)) {
- // pow(x, -1.0) -> 1.0/x
- Value *R = BinaryOperator::createFDiv(ConstantFP::get(CI->getType(), 1.0),
- Op1, CI->getName()+".pow", CI);
- return ReplaceCallWith(CI, R);
- }
- return false; // opt failed
- }
-};
-
-PowOptimization PowFOptimizer("powf");
-PowOptimization PowOptimizer("pow");
-PowOptimization PowLOptimizer("powl");
-
-
-/// This LibCallOptimization will simplify calls to the "printf" library
-/// function. It looks for cases where the result of printf is not used and the
-/// operation can be reduced to something simpler.
-/// @brief Simplify the printf library function.
-struct VISIBILITY_HIDDEN PrintfOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- PrintfOptimization() : LibCallOptimization("printf",
- "Number of 'printf' calls simplified") {}
-
- /// @brief Make sure that the "printf" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- // Just make sure this has at least 1 argument and returns an integer or
- // void type.
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() >= 1 &&
- (isa<IntegerType>(FT->getReturnType()) ||
- FT->getReturnType() == Type::VoidTy);
- }
-
- /// @brief Perform the printf optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // All the optimizations depend on the length of the first argument and the
- // fact that it is a constant string array. Check that now
- std::string FormatStr;
- if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
- return false;
-
- // If this is a simple constant string with no format specifiers that ends
- // with a \n, turn it into a puts call.
- if (FormatStr.empty()) {
- // Tolerate printf's declared void.
- if (CI->use_empty()) return ReplaceCallWith(CI, 0);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
- }
-
- if (FormatStr.size() == 1) {
- // Turn this into a putchar call, even if it is a %.
- Value *V = ConstantInt::get(Type::Int32Ty, FormatStr[0]);
- CallInst::Create(SLC.get_putchar(), V, "", CI);
- if (CI->use_empty()) return ReplaceCallWith(CI, 0);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
- }
-
- // Check to see if the format str is something like "foo\n", in which case
- // we convert it to a puts call. We don't allow it to contain any format
- // characters.
- if (FormatStr[FormatStr.size()-1] == '\n' &&
- FormatStr.find('%') == std::string::npos) {
- // Create a string literal with no \n on it. We expect the constant merge
- // pass to be run after this pass, to merge duplicate strings.
- FormatStr.erase(FormatStr.end()-1);
- Constant *Init = ConstantArray::get(FormatStr, true);
- Constant *GV = new GlobalVariable(Init->getType(), true,
- GlobalVariable::InternalLinkage,
- Init, "str",
- CI->getParent()->getParent()->getParent());
- // Cast GV to be a pointer to char.
- GV = ConstantExpr::getBitCast(GV, PointerType::getUnqual(Type::Int8Ty));
- CallInst::Create(SLC.get_puts(), GV, "", CI);
-
- if (CI->use_empty()) return ReplaceCallWith(CI, 0);
- // The return value from printf includes the \n we just removed, so +1.
- return ReplaceCallWith(CI,
- ConstantInt::get(CI->getType(),
- FormatStr.size()+1));
- }
-
-
- // Only support %c or "%s\n" for now.
- if (FormatStr.size() < 2 || FormatStr[0] != '%')
- return false;
-
- // Get the second character and switch on its value
- switch (FormatStr[1]) {
- default: return false;
- case 's':
- if (FormatStr != "%s\n" || CI->getNumOperands() < 3 ||
- // TODO: could insert strlen call to compute string length.
- !CI->use_empty())
- return false;
-
- // printf("%s\n",str) -> puts(str)
- CallInst::Create(SLC.get_puts(), CastToCStr(CI->getOperand(2), CI),
- CI->getName(), CI);
- return ReplaceCallWith(CI, 0);
- case 'c': {
- // printf("%c",c) -> putchar(c)
- if (FormatStr.size() != 2 || CI->getNumOperands() < 3)
- return false;
-
- Value *V = CI->getOperand(2);
- if (!isa<IntegerType>(V->getType()) ||
- cast<IntegerType>(V->getType())->getBitWidth() > 32)
- return false;
-
- V = CastInst::createZExtOrBitCast(V, Type::Int32Ty, CI->getName()+".int",
- CI);
- CallInst::Create(SLC.get_putchar(), V, "", CI);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
- }
- }
- }
-} PrintfOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "fprintf" library
-/// function. It looks for cases where the result of fprintf is not used and the
-/// operation can be reduced to something simpler.
-/// @brief Simplify the fprintf library function.
-struct VISIBILITY_HIDDEN FPrintFOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- FPrintFOptimization() : LibCallOptimization("fprintf",
- "Number of 'fprintf' calls simplified") {}
-
- /// @brief Make sure that the "fprintf" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 && // two fixed arguments.
- FT->getParamType(1) == PointerType::getUnqual(Type::Int8Ty) &&
- isa<PointerType>(FT->getParamType(0)) &&
- isa<IntegerType>(FT->getReturnType());
- }
-
- /// @brief Perform the fprintf optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // If the call has more than 3 operands, we can't optimize it
- if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
- return false;
-
- // All the optimizations depend on the format string.
- std::string FormatStr;
- if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
- return false;
-
- // If this is just a format string, turn it into fwrite.
- if (CI->getNumOperands() == 3) {
- for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
- if (FormatStr[i] == '%')
- return false; // we found a format specifier
-
- // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
- const Type *FILEty = CI->getOperand(1)->getType();
-
- Value *FWriteArgs[] = {
- CI->getOperand(2),
- ConstantInt::get(SLC.getIntPtrType(), FormatStr.size()),
- ConstantInt::get(SLC.getIntPtrType(), 1),
- CI->getOperand(1)
- };
- CallInst::Create(SLC.get_fwrite(FILEty), FWriteArgs, FWriteArgs + 4, CI->getName(), CI);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
- FormatStr.size()));
- }
-
- // The remaining optimizations require the format string to be length 2:
- // "%s" or "%c".
- if (FormatStr.size() != 2 || FormatStr[0] != '%')
- return false;
-
- // Get the second character and switch on its value
- switch (FormatStr[1]) {
- case 'c': {
- // fprintf(file,"%c",c) -> fputc(c,file)
- const Type *FILETy = CI->getOperand(1)->getType();
- Value *C = CastInst::createZExtOrBitCast(CI->getOperand(3), Type::Int32Ty,
- CI->getName()+".int", CI);
- SmallVector<Value *, 2> Args;
- Args.push_back(C);
- Args.push_back(CI->getOperand(1));
- CallInst::Create(SLC.get_fputc(FILETy), Args.begin(), Args.end(), "", CI);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
- }
- case 's': {
- const Type *FILETy = CI->getOperand(1)->getType();
-
- // If the result of the fprintf call is used, we can't do this.
- // TODO: we should insert a strlen call.
- if (!CI->use_empty() || !isa<PointerType>(CI->getOperand(3)->getType()))
- return false;
-
- // fprintf(file,"%s",str) -> fputs(str,file)
- SmallVector<Value *, 2> Args;
- Args.push_back(CastToCStr(CI->getOperand(3), CI));
- Args.push_back(CI->getOperand(1));
- CallInst::Create(SLC.get_fputs(FILETy), Args.begin(),
- Args.end(), CI->getName(), CI);
- return ReplaceCallWith(CI, 0);
- }
- default:
- return false;
- }
- }
-} FPrintFOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "sprintf" library
-/// function. It looks for cases where the result of sprintf is not used and the
-/// operation can be reduced to something simpler.
-/// @brief Simplify the sprintf library function.
-struct VISIBILITY_HIDDEN SPrintFOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- SPrintFOptimization() : LibCallOptimization("sprintf",
- "Number of 'sprintf' calls simplified") {}
-
- /// @brief Make sure that the "sprintf" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 2 && // two fixed arguments.
- FT->getParamType(1) == PointerType::getUnqual(Type::Int8Ty) &&
- FT->getParamType(0) == FT->getParamType(1) &&
- isa<IntegerType>(FT->getReturnType());
- }
-
- /// @brief Perform the sprintf optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // If the call has more than 3 operands, we can't optimize it
- if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
- return false;
-
- std::string FormatStr;
- if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
- return false;
-
- if (CI->getNumOperands() == 3) {
- // Make sure there's no % in the constant array
- for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
- if (FormatStr[i] == '%')
- return false; // we found a format specifier
-
- // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
- Value *MemCpyArgs[] = {
- CI->getOperand(1), CI->getOperand(2),
- ConstantInt::get(SLC.getIntPtrType(),
- FormatStr.size()+1), // Copy the nul byte.
- ConstantInt::get(Type::Int32Ty, 1)
- };
- CallInst::Create(SLC.get_memcpy(), MemCpyArgs, MemCpyArgs + 4, "", CI);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
- FormatStr.size()));
- }
-
- // The remaining optimizations require the format string to be "%s" or "%c".
- if (FormatStr.size() != 2 || FormatStr[0] != '%')
- return false;
-
- // Get the second character and switch on its value
- switch (FormatStr[1]) {
- case 'c': {
- // sprintf(dest,"%c",chr) -> store chr, dest
- Value *V = CastInst::createTruncOrBitCast(CI->getOperand(3),
- Type::Int8Ty, "char", CI);
- new StoreInst(V, CI->getOperand(1), CI);
- Value *Ptr = GetElementPtrInst::Create(CI->getOperand(1),
- ConstantInt::get(Type::Int32Ty, 1),
- CI->getOperand(1)->getName()+".end",
- CI);
- new StoreInst(ConstantInt::get(Type::Int8Ty,0), Ptr, CI);
- return ReplaceCallWith(CI, ConstantInt::get(Type::Int32Ty, 1));
- }
- case 's': {
- // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
- Value *Len = CallInst::Create(SLC.get_strlen(),
- CastToCStr(CI->getOperand(3), CI),
- CI->getOperand(3)->getName()+".len", CI);
- Value *UnincLen = Len;
- Len = BinaryOperator::createAdd(Len, ConstantInt::get(Len->getType(), 1),
- Len->getName()+"1", CI);
- Value *MemcpyArgs[4] = {
- CI->getOperand(1),
- CastToCStr(CI->getOperand(3), CI),
- Len,
- ConstantInt::get(Type::Int32Ty, 1)
- };
- CallInst::Create(SLC.get_memcpy(), MemcpyArgs, MemcpyArgs + 4, "", CI);
-
- // The strlen result is the unincremented number of bytes in the string.
- if (!CI->use_empty()) {
- if (UnincLen->getType() != CI->getType())
- UnincLen = CastInst::createIntegerCast(UnincLen, CI->getType(), false,
- Len->getName(), CI);
- CI->replaceAllUsesWith(UnincLen);
- }
- return ReplaceCallWith(CI, 0);
- }
- }
- return false;
- }
-} SPrintFOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "fputs" library
-/// function. It looks for cases where the result of fputs is not used and the
-/// operation can be reduced to something simpler.
-/// @brief Simplify the fputs library function.
-struct VISIBILITY_HIDDEN FPutsOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- FPutsOptimization() : LibCallOptimization("fputs",
- "Number of 'fputs' calls simplified") {}
-
- /// @brief Make sure that the "fputs" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- // Just make sure this has 2 arguments
- return F->arg_size() == 2;
- }
-
- /// @brief Perform the fputs optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // If the result is used, none of these optimizations work.
- if (!CI->use_empty())
- return false;
-
- // All the optimizations depend on the length of the first argument.
- uint64_t Len = GetStringLength(CI->getOperand(1));
- if (!Len) return false;
-
- const Type *FILETy = CI->getOperand(2)->getType();
- // fputs(s,F) -> fwrite(s,1,strlen(s),F)
- Value *Ops[4] = {
- CI->getOperand(1),
- ConstantInt::get(SLC.getIntPtrType(), Len-1),
- ConstantInt::get(SLC.getIntPtrType(), 1),
- CI->getOperand(2)
- };
- CallInst::Create(SLC.get_fwrite(FILETy), Ops, Ops + 4, "", CI);
- return ReplaceCallWith(CI, 0); // Known to have no uses (see above).
- }
-} FPutsOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "fwrite" function.
-struct VISIBILITY_HIDDEN FWriteOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- FWriteOptimization() : LibCallOptimization("fwrite",
- "Number of 'fwrite' calls simplified") {}
-
- /// @brief Make sure that the "fputs" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- const FunctionType *FT = F->getFunctionType();
- return FT->getNumParams() == 4 &&
- FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
- FT->getParamType(1) == FT->getParamType(2) &&
- isa<IntegerType>(FT->getParamType(1)) &&
- isa<PointerType>(FT->getParamType(3)) &&
- isa<IntegerType>(FT->getReturnType());
- }
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // Get the element size and count.
- uint64_t EltSize, EltCount;
- if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
- EltSize = C->getZExtValue();
- else
- return false;
- if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
- EltCount = C->getZExtValue();
- else
- return false;
-
- // If this is writing zero records, remove the call (it's a noop).
- if (EltSize * EltCount == 0)
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
-
- // If this is writing one byte, turn it into fputc.
- if (EltSize == 1 && EltCount == 1) {
- SmallVector<Value *, 2> Args;
- // fwrite(s,1,1,F) -> fputc(s[0],F)
- Value *Ptr = CI->getOperand(1);
- Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
- Args.push_back(new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI));
- Args.push_back(CI->getOperand(4));
- const Type *FILETy = CI->getOperand(4)->getType();
- CallInst::Create(SLC.get_fputc(FILETy), Args.begin(), Args.end(), "", CI);
- return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
- }
- return false;
- }
-} FWriteOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "isdigit" library
-/// function. It simply does range checks the parameter explicitly.
-/// @brief Simplify the isdigit library function.
-struct VISIBILITY_HIDDEN isdigitOptimization : public LibCallOptimization {
-public:
- isdigitOptimization() : LibCallOptimization("isdigit",
- "Number of 'isdigit' calls simplified") {}
-
- /// @brief Make sure that the "isdigit" function has the right prototype
- virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
- // Just make sure this has 1 argument
- return (f->arg_size() == 1);
- }
-
- /// @brief Perform the toascii optimization.
- virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
- if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
- // isdigit(c) -> 0 or 1, if 'c' is constant
- uint64_t val = CI->getZExtValue();
- if (val >= '0' && val <= '9')
- return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 1));
- else
- return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 0));
- }
-
- // isdigit(c) -> (unsigned)c - '0' <= 9
- CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
- Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
- BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
- ConstantInt::get(Type::Int32Ty,0x30),
- ci->getOperand(1)->getName()+".sub",ci);
- ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
- ConstantInt::get(Type::Int32Ty,9),
- ci->getOperand(1)->getName()+".cmp",ci);
- CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
- ci->getOperand(1)->getName()+".isdigit", ci);
- return ReplaceCallWith(ci, c2);
- }
-} isdigitOptimizer;
-
-struct VISIBILITY_HIDDEN isasciiOptimization : public LibCallOptimization {
-public:
- isasciiOptimization()
- : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
-
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
- F->getReturnType()->isInteger();
- }
-
- /// @brief Perform the isascii optimization.
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
- // isascii(c) -> (unsigned)c < 128
- Value *V = CI->getOperand(1);
- Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
- ConstantInt::get(V->getType(), 128),
- V->getName()+".isascii", CI);
- if (Cmp->getType() != CI->getType())
- Cmp = new ZExtInst(Cmp, CI->getType(), Cmp->getName(), CI);
- return ReplaceCallWith(CI, Cmp);
- }
-} isasciiOptimizer;
-
-
-/// This LibCallOptimization will simplify calls to the "toascii" library
-/// function. It simply does the corresponding and operation to restrict the
-/// range of values to the ASCII character set (0-127).
-/// @brief Simplify the toascii library function.
-struct VISIBILITY_HIDDEN ToAsciiOptimization : public LibCallOptimization {
-public:
- /// @brief Default Constructor
- ToAsciiOptimization() : LibCallOptimization("toascii",
- "Number of 'toascii' calls simplified") {}
-
- /// @brief Make sure that the "fputs" function has the right prototype
- virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
- // Just make sure this has 2 arguments
- return (f->arg_size() == 1);
- }
-
- /// @brief Perform the toascii optimization.
- virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
- // toascii(c) -> (c & 0x7f)
- Value *chr = ci->getOperand(1);
- Value *and_inst = BinaryOperator::createAnd(chr,
- ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
- return ReplaceCallWith(ci, and_inst);
- }
-} ToAsciiOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "ffs" library
-/// calls which find the first set bit in an int, long, or long long. The
-/// optimization is to compute the result at compile time if the argument is
-/// a constant.
-/// @brief Simplify the ffs library function.
-struct VISIBILITY_HIDDEN FFSOptimization : public LibCallOptimization {
-protected:
- /// @brief Subclass Constructor
- FFSOptimization(const char* funcName, const char* description)
- : LibCallOptimization(funcName, description) {}
-
-public:
- /// @brief Default Constructor
- FFSOptimization() : LibCallOptimization("ffs",
- "Number of 'ffs' calls simplified") {}
-
- /// @brief Make sure that the "ffs" function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- // Just make sure this has 2 arguments
- return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
- }
-
- /// @brief Perform the ffs optimization.
- virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
- // ffs(cnst) -> bit#
- // ffsl(cnst) -> bit#
- // ffsll(cnst) -> bit#
- uint64_t val = CI->getZExtValue();
- int result = 0;
- if (val) {
- ++result;
- while ((val & 1) == 0) {
- ++result;
- val >>= 1;
- }
- }
- return ReplaceCallWith(TheCall, ConstantInt::get(Type::Int32Ty, result));
- }
-
- // ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
- // ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
- // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
- const Type *ArgType = TheCall->getOperand(1)->getType();
- assert(ArgType->getTypeID() == Type::IntegerTyID &&
- "llvm.cttz argument is not an integer?");
- Constant *F = Intrinsic::getDeclaration(SLC.getModule(),
- Intrinsic::cttz, &ArgType, 1);
-
- Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
- false/*ZExt*/, "tmp", TheCall);
- Value *V2 = CallInst::Create(F, V, "tmp", TheCall);
- V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
- "tmp", TheCall);
- V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
- "tmp", TheCall);
- Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
- Constant::getNullValue(V->getType()), "tmp",
- TheCall);
- V2 = SelectInst::Create(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
- TheCall->getName(), TheCall);
- return ReplaceCallWith(TheCall, V2);
- }
-} FFSOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "ffsl" library
-/// calls. It simply uses FFSOptimization for which the transformation is
-/// identical.
-/// @brief Simplify the ffsl library function.
-struct VISIBILITY_HIDDEN FFSLOptimization : public FFSOptimization {
-public:
- /// @brief Default Constructor
- FFSLOptimization() : FFSOptimization("ffsl",
- "Number of 'ffsl' calls simplified") {}
-
-} FFSLOptimizer;
-
-/// This LibCallOptimization will simplify calls to the "ffsll" library
-/// calls. It simply uses FFSOptimization for which the transformation is
-/// identical.
-/// @brief Simplify the ffsl library function.
-struct VISIBILITY_HIDDEN FFSLLOptimization : public FFSOptimization {
-public:
- /// @brief Default Constructor
- FFSLLOptimization() : FFSOptimization("ffsll",
- "Number of 'ffsll' calls simplified") {}
-
-} FFSLLOptimizer;
-
-/// This optimizes unary functions that take and return doubles.
-struct UnaryDoubleFPOptimizer : public LibCallOptimization {
- UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
- : LibCallOptimization(Fn, Desc) {}
-
- // Make sure that this function has the right prototype
- virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
- return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
- F->getReturnType() == Type::DoubleTy;
- }
-
- /// ShrinkFunctionToFloatVersion - If the input to this function is really a
- /// float, strength reduce this to a float version of the function,
- /// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
- /// when the target supports the destination function and where there can be
- /// no precision loss.
- static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
- Constant *(SimplifyLibCalls::*FP)()){
- if (FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1)))
- if (Cast->getOperand(0)->getType() == Type::FloatTy) {
- Value *New = CallInst::Create((SLC.*FP)(), Cast->getOperand(0),
- CI->getName(), CI);
- New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
- CI->replaceAllUsesWith(New);
- CI->eraseFromParent();
- if (Cast->use_empty())
- Cast->eraseFromParent();
- return true;
- }
- return false;
- }
-};
-
-
-struct VISIBILITY_HIDDEN FloorOptimization : public UnaryDoubleFPOptimizer {
- FloorOptimization()
- : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
-#ifdef HAVE_FLOORF
- // If this is a float argument passed in, convert to floorf.
- if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
- return true;
-#endif
- return false; // opt failed
- }
-} FloorOptimizer;
-
-struct VISIBILITY_HIDDEN CeilOptimization : public UnaryDoubleFPOptimizer {
- CeilOptimization()
- : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
-#ifdef HAVE_CEILF
- // If this is a float argument passed in, convert to ceilf.
- if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
- return true;
-#endif
- return false; // opt failed
- }
-} CeilOptimizer;
-
-struct VISIBILITY_HIDDEN RoundOptimization : public UnaryDoubleFPOptimizer {
- RoundOptimization()
- : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
-#ifdef HAVE_ROUNDF
- // If this is a float argument passed in, convert to roundf.
- if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
- return true;
-#endif
- return false; // opt failed
- }
-} RoundOptimizer;
-
-struct VISIBILITY_HIDDEN RintOptimization : public UnaryDoubleFPOptimizer {
- RintOptimization()
- : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
-#ifdef HAVE_RINTF
- // If this is a float argument passed in, convert to rintf.
- if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
- return true;
-#endif
- return false; // opt failed
- }
-} RintOptimizer;
-
-struct VISIBILITY_HIDDEN NearByIntOptimization : public UnaryDoubleFPOptimizer {
- NearByIntOptimization()
- : UnaryDoubleFPOptimizer("nearbyint",
- "Number of 'nearbyint' calls simplified") {}
-
- virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
-#ifdef HAVE_NEARBYINTF
- // If this is a float argument passed in, convert to nearbyintf.
- if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
- return true;
-#endif
- return false; // opt failed
- }
-} NearByIntOptimizer;
-} // end anon namespace
-
-/// GetConstantStringInfo - This function computes the length of a
-/// null-terminated constant array of integers. This function can't rely on the
-/// size of the constant array because there could be a null terminator in the
-/// middle of the array.
-///
-/// We also have to bail out if we find a non-integer constant initializer
-/// of one of the elements or if there is no null-terminator. The logic
-/// below checks each of these conditions and will return true only if all
-/// conditions are met. If the conditions aren't met, this returns false.
-///
-/// If successful, the \p Array param is set to the constant array being
-/// indexed, the \p Length parameter is set to the length of the null-terminated
-/// string pointed to by V, the \p StartIdx value is set to the first
-/// element of the Array that V points to, and true is returned.
-static bool GetConstantStringInfo(Value *V, std::string &Str) {
- // Look through noop bitcast instructions.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
- if (BCI->getType() == BCI->getOperand(0)->getType())
- return GetConstantStringInfo(BCI->getOperand(0), Str);
- return false;
- }
-
- // If the value is not a GEP instruction nor a constant expression with a
- // GEP instruction, then return false because ConstantArray can't occur
- // any other way
- User *GEP = 0;
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
- GEP = GEPI;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
- if (CE->getOpcode() != Instruction::GetElementPtr)
- return false;
- GEP = CE;
- } else {
- return false;
- }
-
- // Make sure the GEP has exactly three arguments.
- if (GEP->getNumOperands() != 3)
- return false;
-
- // Check to make sure that the first operand of the GEP is an integer and
- // has value 0 so that we are sure we're indexing into the initializer.
- if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
- if (!Idx->isZero())
- return false;
- } else
- return false;
-
- // If the second index isn't a ConstantInt, then this is a variable index
- // into the array. If this occurs, we can't say anything meaningful about
- // the string.
- uint64_t StartIdx = 0;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
- StartIdx = CI->getZExtValue();
- else
- return false;
-
- // The GEP instruction, constant or instruction, must reference a global
- // variable that is a constant and is initialized. The referenced constant
- // initializer is the array that we'll use for optimization.
- GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
- if (!GV || !GV->isConstant() || !GV->hasInitializer())
- return false;
- Constant *GlobalInit = GV->getInitializer();
-
- // Handle the ConstantAggregateZero case
- if (isa<ConstantAggregateZero>(GlobalInit)) {
- // This is a degenerate case. The initializer is constant zero so the
- // length of the string must be zero.
- Str.clear();
- return true;
- }
-
- // Must be a Constant Array
- ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (!Array) return false;
-
- // Get the number of elements in the array
- uint64_t NumElts = Array->getType()->getNumElements();
-
- // Traverse the constant array from StartIdx (derived above) which is
- // the place the GEP refers to in the array.
- for (unsigned i = StartIdx; i < NumElts; ++i) {
- Constant *Elt = Array->getOperand(i);
- ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
- if (!CI) // This array isn't suitable, non-int initializer.
- return false;
- if (CI->isZero())
- return true; // we found end of string, success!
- Str += (char)CI->getZExtValue();
- }
-
- return false; // The array isn't null terminated.
-}
-
-/// GetStringLengthH - If we can compute the length of the string pointed to by
-/// the specified pointer, return 'len+1'. If we can't, return 0.
-static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
- // Look through noop bitcast instructions.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
- return GetStringLengthH(BCI->getOperand(0), PHIs);
-
- // If this is a PHI node, there are two cases: either we have already seen it
- // or we haven't.
- if (PHINode *PN = dyn_cast<PHINode>(V)) {
- if (!PHIs.insert(PN))
- return ~0ULL; // already in the set.
-
- // If it was new, see if all the input strings are the same length.
- uint64_t LenSoFar = ~0ULL;
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- uint64_t Len = GetStringLengthH(PN->getIncomingValue(i), PHIs);
- if (Len == 0) return 0; // Unknown length -> unknown.
-
- if (Len == ~0ULL) continue;
-
- if (Len != LenSoFar && LenSoFar != ~0ULL)
- return 0; // Disagree -> unknown.
- LenSoFar = Len;
- }
-
- // Success, all agree.
- return LenSoFar;
- }
-
- // strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
- if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
- uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs);
- if (Len1 == 0) return 0;
- uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs);
- if (Len2 == 0) return 0;
- if (Len1 == ~0ULL) return Len2;
- if (Len2 == ~0ULL) return Len1;
- if (Len1 != Len2) return 0;
- return Len1;
- }
-
- // If the value is not a GEP instruction nor a constant expression with a
- // GEP instruction, then return unknown.
- User *GEP = 0;
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
- GEP = GEPI;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
- if (CE->getOpcode() != Instruction::GetElementPtr)
- return 0;
- GEP = CE;
- } else {
- return 0;
- }
-
- // Make sure the GEP has exactly three arguments.
- if (GEP->getNumOperands() != 3)
- return 0;
-
- // Check to make sure that the first operand of the GEP is an integer and
- // has value 0 so that we are sure we're indexing into the initializer.
- if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
- if (!Idx->isZero())
- return 0;
- } else
- return 0;
-
- // If the second index isn't a ConstantInt, then this is a variable index
- // into the array. If this occurs, we can't say anything meaningful about
- // the string.
- uint64_t StartIdx = 0;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
- StartIdx = CI->getZExtValue();
- else
- return 0;
-
- // The GEP instruction, constant or instruction, must reference a global
- // variable that is a constant and is initialized. The referenced constant
- // initializer is the array that we'll use for optimization.
- GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
- if (!GV || !GV->isConstant() || !GV->hasInitializer())
- return 0;
- Constant *GlobalInit = GV->getInitializer();
-
- // Handle the ConstantAggregateZero case, which is a degenerate case. The
- // initializer is constant zero so the length of the string must be zero.
- if (isa<ConstantAggregateZero>(GlobalInit))
- return 1; // Len = 0 offset by 1.
-
- // Must be a Constant Array
- ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (!Array || Array->getType()->getElementType() != Type::Int8Ty)
- return false;
-
- // Get the number of elements in the array
- uint64_t NumElts = Array->getType()->getNumElements();
-
- // Traverse the constant array from StartIdx (derived above) which is
- // the place the GEP refers to in the array.
- for (unsigned i = StartIdx; i != NumElts; ++i) {
- Constant *Elt = Array->getOperand(i);
- ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
- if (!CI) // This array isn't suitable, non-int initializer.
- return 0;
- if (CI->isZero())
- return i-StartIdx+1; // We found end of string, success!
- }
-
- return 0; // The array isn't null terminated, conservatively return 'unknown'.
-}
-
-/// GetStringLength - If we can compute the length of the string pointed to by
-/// the specified pointer, return 'len+1'. If we can't, return 0.
-static uint64_t GetStringLength(Value *V) {
- if (!isa<PointerType>(V->getType())) return 0;
-
- SmallPtrSet<PHINode*, 32> PHIs;
- uint64_t Len = GetStringLengthH(V, PHIs);
- // If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
- // an empty string as a length.
- return Len == ~0ULL ? 1 : Len;
-}
-
-
-
-/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
-/// inserting the cast before IP, and return the cast.
-/// @brief Cast a value to a "C" string.
-static Value *CastToCStr(Value *V, Instruction *IP) {
- assert(isa<PointerType>(V->getType()) &&
- "Can't cast non-pointer type to C string type");
- const Type *SBPTy = PointerType::getUnqual(Type::Int8Ty);
- if (V->getType() != SBPTy)
- return new BitCastInst(V, SBPTy, V->getName(), IP);
- return V;
-}
-
-// TODO:
-// Additional cases that we need to add to this file:
-//
-// cbrt:
-// * cbrt(expN(X)) -> expN(x/3)
-// * cbrt(sqrt(x)) -> pow(x,1/6)
-// * cbrt(sqrt(x)) -> pow(x,1/9)
-//
-// cos, cosf, cosl:
-// * cos(-x) -> cos(x)
-//
-// exp, expf, expl:
-// * exp(log(x)) -> x
-//
-// log, logf, logl:
-// * log(exp(x)) -> x
-// * log(x**y) -> y*log(x)
-// * log(exp(y)) -> y*log(e)
-// * log(exp2(y)) -> y*log(2)
-// * log(exp10(y)) -> y*log(10)
-// * log(sqrt(x)) -> 0.5*log(x)
-// * log(pow(x,y)) -> y*log(x)
-//
-// lround, lroundf, lroundl:
-// * lround(cnst) -> cnst'
-//
-// memcmp:
-// * memcmp(x,y,l) -> cnst
-// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
-//
-// memmove:
-// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
-// (if s is a global constant array)
-//
-// pow, powf, powl:
-// * pow(exp(x),y) -> exp(x*y)
-// * pow(sqrt(x),y) -> pow(x,y*0.5)
-// * pow(pow(x,y),z)-> pow(x,y*z)
-//
-// puts:
-// * puts("") -> putchar("\n")
-//
-// round, roundf, roundl:
-// * round(cnst) -> cnst'
-//
-// signbit:
-// * signbit(cnst) -> cnst'
-// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
-//
-// sqrt, sqrtf, sqrtl:
-// * sqrt(expN(x)) -> expN(x*0.5)
-// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
-// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
-//
-// stpcpy:
-// * stpcpy(str, "literal") ->
-// llvm.memcpy(str,"literal",strlen("literal")+1,1)
-// strrchr:
-// * strrchr(s,c) -> reverse_offset_of_in(c,s)
-// (if c is a constant integer and s is a constant string)
-// * strrchr(s1,0) -> strchr(s1,0)
-//
-// strncat:
-// * strncat(x,y,0) -> x
-// * strncat(x,y,0) -> x (if strlen(y) = 0)
-// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
-//
-// strncpy:
-// * strncpy(d,s,0) -> d
-// * strncpy(d,s,l) -> memcpy(d,s,l,1)
-// (if s and l are constants)
-//
-// strpbrk:
-// * strpbrk(s,a) -> offset_in_for(s,a)
-// (if s and a are both constant strings)
-// * strpbrk(s,"") -> 0
-// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
-//
-// strspn, strcspn:
-// * strspn(s,a) -> const_int (if both args are constant)
-// * strspn("",a) -> 0
-// * strspn(s,"") -> 0
-// * strcspn(s,a) -> const_int (if both args are constant)
-// * strcspn("",a) -> 0
-// * strcspn(s,"") -> strlen(a)
-//
-// strstr:
-// * strstr(x,x) -> x
-// * strstr(s1,s2) -> offset_of_s2_in(s1)
-// (if s1 and s2 are constant strings)
-//
-// tan, tanf, tanl:
-// * tan(atan(x)) -> x
-//
-// trunc, truncf, truncl:
-// * trunc(cnst) -> cnst'
-//
-//
--- /dev/null
+//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a simple pass that applies a variety of small
+// optimizations for calls to specific well-known function calls (e.g. runtime
+// library functions). For example, a call to the function "exit(3)" that
+// occurs within the main() function can be transformed into a simple "return 3"
+// instruction. Any optimization that takes this form (replace call to library
+// function with simpler code that provides the same result) belongs in this
+// file.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "simplify-libcalls"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Config/config.h"
+using namespace llvm;
+
+STATISTIC(NumSimplified, "Number of library calls simplified");
+
+//===----------------------------------------------------------------------===//
+// Optimizer Base Class
+//===----------------------------------------------------------------------===//
+
+/// This class is the abstract base class for the set of optimizations that
+/// corresponds to one library call.
+namespace {
+class VISIBILITY_HIDDEN LibCallOptimization {
+protected:
+ Function *Caller;
+ const TargetData *TD;
+public:
+ LibCallOptimization() { }
+ virtual ~LibCallOptimization() {}
+
+ /// CallOptimizer - This pure virtual method is implemented by base classes to
+ /// do various optimizations. If this returns null then no transformation was
+ /// performed. If it returns CI, then it transformed the call and CI is to be
+ /// deleted. If it returns something else, replace CI with the new value and
+ /// delete CI.
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) =0;
+
+ Value *OptimizeCall(CallInst *CI, const TargetData &TD, IRBuilder &B) {
+ Caller = CI->getParent()->getParent();
+ this->TD = &TD;
+ return CallOptimizer(CI->getCalledFunction(), CI, B);
+ }
+
+ /// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
+ Value *CastToCStr(Value *V, IRBuilder &B);
+
+ /// EmitStrLen - Emit a call to the strlen function to the builder, for the
+ /// specified pointer. Ptr is required to be some pointer type, and the
+ /// return value has 'intptr_t' type.
+ Value *EmitStrLen(Value *Ptr, IRBuilder &B);
+
+ /// EmitMemCpy - Emit a call to the memcpy function to the builder. This
+ /// always expects that the size has type 'intptr_t' and Dst/Src are pointers.
+ Value *EmitMemCpy(Value *Dst, Value *Src, Value *Len,
+ unsigned Align, IRBuilder &B);
+
+ /// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
+ /// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
+ Value *EmitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder &B);
+
+ /// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
+ /// 'floor'). This function is known to take a single of type matching 'Op'
+ /// and returns one value with the same type. If 'Op' is a long double, 'l'
+ /// is added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
+ Value *EmitUnaryFloatFnCall(Value *Op, const char *Name, IRBuilder &B);
+
+ /// EmitPutChar - Emit a call to the putchar function. This assumes that Char
+ /// is an integer.
+ void EmitPutChar(Value *Char, IRBuilder &B);
+
+ /// EmitPutS - Emit a call to the puts function. This assumes that Str is
+ /// some pointer.
+ void EmitPutS(Value *Str, IRBuilder &B);
+
+ /// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
+ /// an i32, and File is a pointer to FILE.
+ void EmitFPutC(Value *Char, Value *File, IRBuilder &B);
+
+ /// EmitFPutS - Emit a call to the puts function. Str is required to be a
+ /// pointer and File is a pointer to FILE.
+ void EmitFPutS(Value *Str, Value *File, IRBuilder &B);
+
+ /// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
+ /// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
+ void EmitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder &B);
+
+};
+} // End anonymous namespace.
+
+/// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
+Value *LibCallOptimization::CastToCStr(Value *V, IRBuilder &B) {
+ return B.CreateBitCast(V, PointerType::getUnqual(Type::Int8Ty), "cstr");
+}
+
+/// EmitStrLen - Emit a call to the strlen function to the builder, for the
+/// specified pointer. This always returns an integer value of size intptr_t.
+Value *LibCallOptimization::EmitStrLen(Value *Ptr, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *StrLen =M->getOrInsertFunction("strlen", TD->getIntPtrType(),
+ PointerType::getUnqual(Type::Int8Ty),
+ NULL);
+ return B.CreateCall(StrLen, CastToCStr(Ptr, B), "strlen");
+}
+
+/// EmitMemCpy - Emit a call to the memcpy function to the builder. This always
+/// expects that the size has type 'intptr_t' and Dst/Src are pointers.
+Value *LibCallOptimization::EmitMemCpy(Value *Dst, Value *Src, Value *Len,
+ unsigned Align, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Intrinsic::ID IID = TD->getIntPtrType() == Type::Int32Ty ?
+ Intrinsic::memcpy_i32 : Intrinsic::memcpy_i64;
+ Value *MemCpy = Intrinsic::getDeclaration(M, IID);
+ return B.CreateCall4(MemCpy, CastToCStr(Dst, B), CastToCStr(Src, B), Len,
+ ConstantInt::get(Type::Int32Ty, Align));
+}
+
+/// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
+/// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
+Value *LibCallOptimization::EmitMemChr(Value *Ptr, Value *Val,
+ Value *Len, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *MemChr = M->getOrInsertFunction("memchr",
+ PointerType::getUnqual(Type::Int8Ty),
+ PointerType::getUnqual(Type::Int8Ty),
+ Type::Int32Ty, TD->getIntPtrType(),
+ NULL);
+ return B.CreateCall3(MemChr, CastToCStr(Ptr, B), Val, Len, "memchr");
+}
+
+/// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
+/// 'floor'). This function is known to take a single of type matching 'Op' and
+/// returns one value with the same type. If 'Op' is a long double, 'l' is
+/// added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
+Value *LibCallOptimization::EmitUnaryFloatFnCall(Value *Op, const char *Name,
+ IRBuilder &B) {
+ char NameBuffer[20];
+ if (Op->getType() != Type::DoubleTy) {
+ // If we need to add a suffix, copy into NameBuffer.
+ unsigned NameLen = strlen(Name);
+ assert(NameLen < sizeof(NameBuffer)-2);
+ memcpy(NameBuffer, Name, NameLen);
+ if (Op->getType() == Type::FloatTy)
+ NameBuffer[NameLen] = 'f'; // floorf
+ else
+ NameBuffer[NameLen] = 'l'; // floorl
+ NameBuffer[NameLen+1] = 0;
+ Name = NameBuffer;
+ }
+
+ Module *M = Caller->getParent();
+ Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
+ Op->getType(), NULL);
+ return B.CreateCall(Callee, Op, Name);
+}
+
+/// EmitPutChar - Emit a call to the putchar function. This assumes that Char
+/// is an integer.
+void LibCallOptimization::EmitPutChar(Value *Char, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *F = M->getOrInsertFunction("putchar", Type::Int32Ty,
+ Type::Int32Ty, NULL);
+ B.CreateCall(F, B.CreateIntCast(Char, Type::Int32Ty, "chari"), "putchar");
+}
+
+/// EmitPutS - Emit a call to the puts function. This assumes that Str is
+/// some pointer.
+void LibCallOptimization::EmitPutS(Value *Str, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *F = M->getOrInsertFunction("puts", Type::Int32Ty,
+ PointerType::getUnqual(Type::Int8Ty), NULL);
+ B.CreateCall(F, CastToCStr(Str, B), "puts");
+}
+
+/// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
+/// an integer and File is a pointer to FILE.
+void LibCallOptimization::EmitFPutC(Value *Char, Value *File, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
+ File->getType(), NULL);
+ Char = B.CreateIntCast(Char, Type::Int32Ty, "chari");
+ B.CreateCall2(F, Char, File, "fputc");
+}
+
+/// EmitFPutS - Emit a call to the puts function. Str is required to be a
+/// pointer and File is a pointer to FILE.
+void LibCallOptimization::EmitFPutS(Value *Str, Value *File, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fputs", Type::Int32Ty,
+ PointerType::getUnqual(Type::Int8Ty),
+ File->getType(), NULL);
+ B.CreateCall2(F, CastToCStr(Str, B), File, "fputs");
+}
+
+/// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
+/// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
+void LibCallOptimization::EmitFWrite(Value *Ptr, Value *Size, Value *File,
+ IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
+ PointerType::getUnqual(Type::Int8Ty),
+ TD->getIntPtrType(), TD->getIntPtrType(),
+ File->getType(), NULL);
+ B.CreateCall4(F, CastToCStr(Ptr, B), Size,
+ ConstantInt::get(TD->getIntPtrType(), 1), File);
+}
+
+//===----------------------------------------------------------------------===//
+// Helper Functions
+//===----------------------------------------------------------------------===//
+
+/// GetConstantStringInfo - This function computes the length of a
+/// null-terminated C string pointed to by V. If successful, it returns true
+/// and returns the string in Str. If unsuccessful, it returns false.
+static bool GetConstantStringInfo(Value *V, std::string &Str) {
+ // Look bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ return GetConstantStringInfo(BCI->getOperand(0), Str);
+
+ // If the value is not a GEP instruction nor a constant expression with a
+ // GEP instruction, then return false because ConstantArray can't occur
+ // any other way
+ User *GEP = 0;
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
+ GEP = GEPI;
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() != Instruction::GetElementPtr)
+ return false;
+ GEP = CE;
+ } else {
+ return false;
+ }
+
+ // Make sure the GEP has exactly three arguments.
+ if (GEP->getNumOperands() != 3)
+ return false;
+
+ // Check to make sure that the first operand of the GEP is an integer and
+ // has value 0 so that we are sure we're indexing into the initializer.
+ if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
+ if (!Idx->isZero())
+ return false;
+ } else
+ return false;
+
+ // If the second index isn't a ConstantInt, then this is a variable index
+ // into the array. If this occurs, we can't say anything meaningful about
+ // the string.
+ uint64_t StartIdx = 0;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
+ StartIdx = CI->getZExtValue();
+ else
+ return false;
+
+ // The GEP instruction, constant or instruction, must reference a global
+ // variable that is a constant and is initialized. The referenced constant
+ // initializer is the array that we'll use for optimization.
+ GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
+ if (!GV || !GV->isConstant() || !GV->hasInitializer())
+ return false;
+ Constant *GlobalInit = GV->getInitializer();
+
+ // Handle the ConstantAggregateZero case
+ if (isa<ConstantAggregateZero>(GlobalInit)) {
+ // This is a degenerate case. The initializer is constant zero so the
+ // length of the string must be zero.
+ Str.clear();
+ return true;
+ }
+
+ // Must be a Constant Array
+ ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty)
+ return false;
+
+ // Get the number of elements in the array
+ uint64_t NumElts = Array->getType()->getNumElements();
+
+ // Traverse the constant array from StartIdx (derived above) which is
+ // the place the GEP refers to in the array.
+ for (unsigned i = StartIdx; i < NumElts; ++i) {
+ Constant *Elt = Array->getOperand(i);
+ ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+ if (!CI) // This array isn't suitable, non-int initializer.
+ return false;
+ if (CI->isZero())
+ return true; // we found end of string, success!
+ Str += (char)CI->getZExtValue();
+ }
+
+ return false; // The array isn't null terminated.
+}
+
+/// GetStringLengthH - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
+ // Look through noop bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ return GetStringLengthH(BCI->getOperand(0), PHIs);
+
+ // If this is a PHI node, there are two cases: either we have already seen it
+ // or we haven't.
+ if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (!PHIs.insert(PN))
+ return ~0ULL; // already in the set.
+
+ // If it was new, see if all the input strings are the same length.
+ uint64_t LenSoFar = ~0ULL;
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+ uint64_t Len = GetStringLengthH(PN->getIncomingValue(i), PHIs);
+ if (Len == 0) return 0; // Unknown length -> unknown.
+
+ if (Len == ~0ULL) continue;
+
+ if (Len != LenSoFar && LenSoFar != ~0ULL)
+ return 0; // Disagree -> unknown.
+ LenSoFar = Len;
+ }
+
+ // Success, all agree.
+ return LenSoFar;
+ }
+
+ // strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
+ if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
+ uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs);
+ if (Len1 == 0) return 0;
+ uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs);
+ if (Len2 == 0) return 0;
+ if (Len1 == ~0ULL) return Len2;
+ if (Len2 == ~0ULL) return Len1;
+ if (Len1 != Len2) return 0;
+ return Len1;
+ }
+
+ // If the value is not a GEP instruction nor a constant expression with a
+ // GEP instruction, then return unknown.
+ User *GEP = 0;
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
+ GEP = GEPI;
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() != Instruction::GetElementPtr)
+ return 0;
+ GEP = CE;
+ } else {
+ return 0;
+ }
+
+ // Make sure the GEP has exactly three arguments.
+ if (GEP->getNumOperands() != 3)
+ return 0;
+
+ // Check to make sure that the first operand of the GEP is an integer and
+ // has value 0 so that we are sure we're indexing into the initializer.
+ if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
+ if (!Idx->isZero())
+ return 0;
+ } else
+ return 0;
+
+ // If the second index isn't a ConstantInt, then this is a variable index
+ // into the array. If this occurs, we can't say anything meaningful about
+ // the string.
+ uint64_t StartIdx = 0;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
+ StartIdx = CI->getZExtValue();
+ else
+ return 0;
+
+ // The GEP instruction, constant or instruction, must reference a global
+ // variable that is a constant and is initialized. The referenced constant
+ // initializer is the array that we'll use for optimization.
+ GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
+ if (!GV || !GV->isConstant() || !GV->hasInitializer())
+ return 0;
+ Constant *GlobalInit = GV->getInitializer();
+
+ // Handle the ConstantAggregateZero case, which is a degenerate case. The
+ // initializer is constant zero so the length of the string must be zero.
+ if (isa<ConstantAggregateZero>(GlobalInit))
+ return 1; // Len = 0 offset by 1.
+
+ // Must be a Constant Array
+ ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (!Array || Array->getType()->getElementType() != Type::Int8Ty)
+ return false;
+
+ // Get the number of elements in the array
+ uint64_t NumElts = Array->getType()->getNumElements();
+
+ // Traverse the constant array from StartIdx (derived above) which is
+ // the place the GEP refers to in the array.
+ for (unsigned i = StartIdx; i != NumElts; ++i) {
+ Constant *Elt = Array->getOperand(i);
+ ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+ if (!CI) // This array isn't suitable, non-int initializer.
+ return 0;
+ if (CI->isZero())
+ return i-StartIdx+1; // We found end of string, success!
+ }
+
+ return 0; // The array isn't null terminated, conservatively return 'unknown'.
+}
+
+/// GetStringLength - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+static uint64_t GetStringLength(Value *V) {
+ if (!isa<PointerType>(V->getType())) return 0;
+
+ SmallPtrSet<PHINode*, 32> PHIs;
+ uint64_t Len = GetStringLengthH(V, PHIs);
+ // If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
+ // an empty string as a length.
+ return Len == ~0ULL ? 1 : Len;
+}
+
+/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
+/// value is equal or not-equal to zero.
+static bool IsOnlyUsedInZeroEqualityComparison(Value *V) {
+ for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
+ UI != E; ++UI) {
+ if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
+ if (IC->isEquality())
+ if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
+ if (C->isNullValue())
+ continue;
+ // Unknown instruction.
+ return false;
+ }
+ return true;
+}
+
+//===----------------------------------------------------------------------===//
+// Miscellaneous LibCall Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'exit' Optimizations
+
+/// ExitOpt - int main() { exit(4); } --> int main() { return 4; }
+struct VISIBILITY_HIDDEN ExitOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify we have a reasonable prototype for exit.
+ if (Callee->arg_size() == 0 || !CI->use_empty())
+ return 0;
+
+ // Verify the caller is main, and that the result type of main matches the
+ // argument type of exit.
+ if (!Caller->isName("main") || !Caller->hasExternalLinkage() ||
+ Caller->getReturnType() != CI->getOperand(1)->getType())
+ return 0;
+
+ TerminatorInst *OldTI = CI->getParent()->getTerminator();
+
+ // Create the return after the call.
+ ReturnInst *RI = B.CreateRet(CI->getOperand(1));
+
+ // Drop all successor phi node entries.
+ for (unsigned i = 0, e = OldTI->getNumSuccessors(); i != e; ++i)
+ OldTI->getSuccessor(i)->removePredecessor(CI->getParent());
+
+ // Erase all instructions from after our return instruction until the end of
+ // the block.
+ BasicBlock::iterator FirstDead = RI; ++FirstDead;
+ CI->getParent()->getInstList().erase(FirstDead, CI->getParent()->end());
+ return CI;
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// String and Memory LibCall Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'strcat' Optimizations
+
+struct VISIBILITY_HIDDEN StrCatOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcat" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
+ FT->getParamType(0) != FT->getReturnType() ||
+ FT->getParamType(1) != FT->getReturnType())
+ return 0;
+
+ // Extract some information from the instruction
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+
+ // See if we can get the length of the input string.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return false;
+ --Len; // Unbias length.
+
+ // Handle the simple, do-nothing case: strcat(x, "") -> x
+ if (Len == 0)
+ return Dst;
+
+ // We need to find the end of the destination string. That's where the
+ // memory is to be moved to. We just generate a call to strlen.
+ Value *DstLen = EmitStrLen(Dst, B);
+
+ // Now that we have the destination's length, we must index into the
+ // destination's pointer to get the actual memcpy destination (end of
+ // the string .. we're concatenating).
+ Dst = B.CreateGEP(Dst, DstLen, "endptr");
+
+ // We have enough information to now generate the memcpy call to do the
+ // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
+ EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len+1), 1, B);
+ return Dst;
+ }
+};
+
+//===---------------------------------------===//
+// 'strchr' Optimizations
+
+struct VISIBILITY_HIDDEN StrChrOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strchr" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
+ FT->getParamType(0) != FT->getReturnType())
+ return 0;
+
+ Value *SrcStr = CI->getOperand(1);
+
+ // If the second operand is non-constant, see if we can compute the length
+ // of the input string and turn this into memchr.
+ ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getOperand(2));
+ if (CharC == 0) {
+ uint64_t Len = GetStringLength(SrcStr);
+ if (Len == 0 || FT->getParamType(1) != Type::Int32Ty) // memchr needs i32.
+ return 0;
+
+ return EmitMemChr(SrcStr, CI->getOperand(2), // include nul.
+ ConstantInt::get(TD->getIntPtrType(), Len), B);
+ }
+
+ // Otherwise, the character is a constant, see if the first argument is
+ // a string literal. If so, we can constant fold.
+ std::string Str;
+ if (!GetConstantStringInfo(SrcStr, Str))
+ return false;
+
+ // strchr can find the nul character.
+ Str += '\0';
+ char CharValue = CharC->getSExtValue();
+
+ // Compute the offset.
+ uint64_t i = 0;
+ while (1) {
+ if (i == Str.size()) // Didn't find the char. strchr returns null.
+ return Constant::getNullValue(CI->getType());
+ // Did we find our match?
+ if (Str[i] == CharValue)
+ break;
+ ++i;
+ }
+
+ // strchr(s+n,c) -> gep(s+n+i,c)
+ Value *Idx = ConstantInt::get(Type::Int64Ty, i);
+ return B.CreateGEP(SrcStr, Idx, "strchr");
+ }
+};
+
+//===---------------------------------------===//
+// 'strcmp' Optimizations
+
+struct VISIBILITY_HIDDEN StrCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcmp" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || FT->getReturnType() != Type::Int32Ty ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strcmp(x,x) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
+ return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
+
+ if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
+ return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+
+ // strcmp(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(), strcmp(Str1.c_str(),Str2.c_str()));
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'strncmp' Optimizations
+
+struct VISIBILITY_HIDDEN StrNCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strncmp" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != Type::Int32Ty ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
+ !isa<IntegerType>(FT->getParamType(2)))
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strncmp(x,x,n) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ // Get the length argument if it is constant.
+ uint64_t Length;
+ if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
+ Length = LengthArg->getZExtValue();
+ else
+ return 0;
+
+ if (Length == 0) // strncmp(x,y,0) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> *x
+ return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
+
+ if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
+ return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+
+ // strncmp(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(),
+ strncmp(Str1.c_str(), Str2.c_str(), Length));
+ return 0;
+ }
+};
+
+
+//===---------------------------------------===//
+// 'strcpy' Optimizations
+
+struct VISIBILITY_HIDDEN StrCpyOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcpy" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
+ return 0;
+
+ Value *Dst = CI->getOperand(1), *Src = CI->getOperand(2);
+ if (Dst == Src) // strcpy(x,x) -> x
+ return Src;
+
+ // See if we can get the length of the input string.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return false;
+
+ // We have enough information to now generate the memcpy call to do the
+ // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
+ EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len), 1, B);
+ return Dst;
+ }
+};
+
+
+
+//===---------------------------------------===//
+// 'strlen' Optimizations
+
+struct VISIBILITY_HIDDEN StrLenOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 1 ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ Value *Src = CI->getOperand(1);
+
+ // Constant folding: strlen("xyz") -> 3
+ if (uint64_t Len = GetStringLength(Src))
+ return ConstantInt::get(CI->getType(), Len-1);
+
+ // Handle strlen(p) != 0.
+ if (!IsOnlyUsedInZeroEqualityComparison(CI)) return 0;
+
+ // strlen(x) != 0 --> *x != 0
+ // strlen(x) == 0 --> *x == 0
+ return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'memcmp' Optimizations
+
+struct VISIBILITY_HIDDEN MemCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ FT->getReturnType() != Type::Int32Ty)
+ return 0;
+
+ Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
+
+ if (LHS == RHS) // memcmp(s,s,x) -> 0
+ return Constant::getNullValue(CI->getType());
+
+ // Make sure we have a constant length.
+ ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
+ if (!LenC) return false;
+ uint64_t Len = LenC->getZExtValue();
+
+ if (Len == 0) // memcmp(s1,s2,0) -> 0
+ return Constant::getNullValue(CI->getType());
+
+ if (Len == 1) { // memcmp(S1,S2,1) -> *LHS - *RHS
+ Value *LHSV = B.CreateLoad(CastToCStr(LHS, B), "lhsv");
+ Value *RHSV = B.CreateLoad(CastToCStr(RHS, B), "rhsv");
+ return B.CreateZExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType());
+ }
+
+ // memcmp(S1,S2,2) != 0 -> (*(short*)LHS ^ *(short*)RHS) != 0
+ // memcmp(S1,S2,4) != 0 -> (*(int*)LHS ^ *(int*)RHS) != 0
+ if ((Len == 2 || Len == 4) && IsOnlyUsedInZeroEqualityComparison(CI)) {
+ LHS = B.CreateBitCast(LHS, PointerType::getUnqual(Type::Int16Ty), "tmp");
+ RHS = B.CreateBitCast(RHS, LHS->getType(), "tmp");
+ LoadInst *LHSV = B.CreateLoad(LHS, "lhsv");
+ LoadInst *RHSV = B.CreateLoad(RHS, "rhsv");
+ LHSV->setAlignment(1); RHSV->setAlignment(1); // Unaligned loads.
+ return B.CreateZExt(B.CreateXor(LHSV, RHSV, "shortdiff"), CI->getType());
+ }
+
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'memcpy' Optimizations
+
+struct VISIBILITY_HIDDEN MemCpyOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
+ !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ FT->getParamType(2) != TD->getIntPtrType())
+ return 0;
+
+ // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2), CI->getOperand(3), 1, B);
+ return CI->getOperand(1);
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Math Library Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'pow*' Optimizations
+
+struct VISIBILITY_HIDDEN PowOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // Just make sure this has 2 arguments of the same FP type, which match the
+ // result type.
+ if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ !FT->getParamType(0)->isFloatingPoint())
+ return 0;
+
+ Value *Op1 = CI->getOperand(1), *Op2 = CI->getOperand(2);
+ if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
+ if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
+ return Op1C;
+ if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
+ return EmitUnaryFloatFnCall(Op2, "exp2", B);
+ }
+
+ ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
+ if (Op2C == 0) return 0;
+
+ if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
+ return ConstantFP::get(CI->getType(), 1.0);
+
+ if (Op2C->isExactlyValue(0.5)) {
+ // FIXME: This is not safe for -0.0 and -inf. This can only be done when
+ // 'unsafe' math optimizations are allowed.
+ // x pow(x, 0.5) sqrt(x)
+ // ---------------------------------------------
+ // -0.0 +0.0 -0.0
+ // -inf +inf NaN
+#if 0
+ // pow(x, 0.5) -> sqrt(x)
+ return B.CreateCall(get_sqrt(), Op1, "sqrt");
+#endif
+ }
+
+ if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
+ return Op1;
+ if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
+ return B.CreateMul(Op1, Op1, "pow2");
+ if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
+ return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), Op1, "powrecip");
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
+
+struct VISIBILITY_HIDDEN UnaryDoubleFPOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 1 || FT->getReturnType() != Type::DoubleTy ||
+ FT->getParamType(0) != Type::DoubleTy)
+ return 0;
+
+ // If this is something like 'floor((double)floatval)', convert to floorf.
+ FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1));
+ if (Cast == 0 || Cast->getOperand(0)->getType() != Type::FloatTy)
+ return 0;
+
+ // floor((double)floatval) -> (double)floorf(floatval)
+ Value *V = Cast->getOperand(0);
+ V = EmitUnaryFloatFnCall(V, Callee->getNameStart(), B);
+ return B.CreateFPExt(V, Type::DoubleTy);
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Integer Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'ffs*' Optimizations
+
+struct VISIBILITY_HIDDEN FFSOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // Just make sure this has 2 arguments of the same FP type, which match the
+ // result type.
+ if (FT->getNumParams() != 1 || FT->getReturnType() != Type::Int32Ty ||
+ !isa<IntegerType>(FT->getParamType(0)))
+ return 0;
+
+ Value *Op = CI->getOperand(1);
+
+ // Constant fold.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+ if (CI->getValue() == 0) // ffs(0) -> 0.
+ return Constant::getNullValue(CI->getType());
+ return ConstantInt::get(Type::Int32Ty, // ffs(c) -> cttz(c)+1
+ CI->getValue().countTrailingZeros()+1);
+ }
+
+ // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
+ const Type *ArgType = Op->getType();
+ Value *F = Intrinsic::getDeclaration(Callee->getParent(),
+ Intrinsic::cttz, &ArgType, 1);
+ Value *V = B.CreateCall(F, Op, "cttz");
+ V = B.CreateAdd(V, ConstantInt::get(Type::Int32Ty, 1), "tmp");
+ V = B.CreateIntCast(V, Type::Int32Ty, false, "tmp");
+
+ Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
+ return B.CreateSelect(Cond, V, ConstantInt::get(Type::Int32Ty, 0));
+ }
+};
+
+//===---------------------------------------===//
+// 'isdigit' Optimizations
+
+struct VISIBILITY_HIDDEN IsDigitOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require integer(i32)
+ if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isdigit(c) -> (c-'0') <u 10
+ Value *Op = CI->getOperand(1);
+ Op = B.CreateSub(Op, ConstantInt::get(Type::Int32Ty, '0'), "isdigittmp");
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 10), "isdigit");
+ return B.CreateZExt(Op, CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'isascii' Optimizations
+
+struct VISIBILITY_HIDDEN IsAsciiOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require integer(i32)
+ if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isascii(c) -> c <u 128
+ Value *Op = CI->getOperand(1);
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 128), "isascii");
+ return B.CreateZExt(Op, CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'toascii' Optimizations
+
+struct VISIBILITY_HIDDEN ToAsciiOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require i32(i32)
+ if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isascii(c) -> c & 0x7f
+ return B.CreateAnd(CI->getOperand(1), ConstantInt::get(CI->getType(),0x7F));
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Formatting and IO Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'printf' Optimizations
+
+struct VISIBILITY_HIDDEN PrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require one fixed pointer argument and an integer/void result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() < 1 || !isa<PointerType>(FT->getParamType(0)) ||
+ !(isa<IntegerType>(FT->getReturnType()) ||
+ FT->getReturnType() == Type::VoidTy))
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
+ return false;
+
+ // Empty format string -> noop.
+ if (FormatStr.empty()) // Tolerate printf's declared void.
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 0);
+
+ // printf("x") -> putchar('x'), even for '%'.
+ if (FormatStr.size() == 1) {
+ EmitPutChar(ConstantInt::get(Type::Int32Ty, FormatStr[0]), B);
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
+ }
+
+ // printf("foo\n") --> puts("foo")
+ if (FormatStr[FormatStr.size()-1] == '\n' &&
+ FormatStr.find('%') == std::string::npos) { // no format characters.
+ // Create a string literal with no \n on it. We expect the constant merge
+ // pass to be run after this pass, to merge duplicate strings.
+ FormatStr.erase(FormatStr.end()-1);
+ Constant *C = ConstantArray::get(FormatStr, true);
+ C = new GlobalVariable(C->getType(), true,GlobalVariable::InternalLinkage,
+ C, "str", Callee->getParent());
+ EmitPutS(C, B);
+ return CI->use_empty() ? (Value*)CI :
+ ConstantInt::get(CI->getType(), FormatStr.size()+1);
+ }
+
+ // Optimize specific format strings.
+ // printf("%c", chr) --> putchar(*(i8*)dst)
+ if (FormatStr == "%c" && CI->getNumOperands() > 2 &&
+ isa<IntegerType>(CI->getOperand(2)->getType())) {
+ EmitPutChar(CI->getOperand(2), B);
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
+ }
+
+ // printf("%s\n", str) --> puts(str)
+ if (FormatStr == "%s\n" && CI->getNumOperands() > 2 &&
+ isa<PointerType>(CI->getOperand(2)->getType()) &&
+ CI->use_empty()) {
+ EmitPutS(CI->getOperand(2), B);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'sprintf' Optimizations
+
+struct VISIBILITY_HIDDEN SPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two fixed pointer arguments and an integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ // If we just have a format string (nothing else crazy) transform it.
+ if (CI->getNumOperands() == 3) {
+ // Make sure there's no % in the constant array. We could try to handle
+ // %% -> % in the future if we cared.
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%')
+ return 0; // we found a format specifier, bail out.
+
+ // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2), // Copy the nul byte.
+ ConstantInt::get(TD->getIntPtrType(), FormatStr.size()+1),1,B);
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c"
+ // and have an extra operand.
+ if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
+ return 0;
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ // sprintf(dst, "%c", chr) --> *(i8*)dst = chr
+ if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
+ Value *V = B.CreateTrunc(CI->getOperand(3), Type::Int8Ty, "char");
+ B.CreateStore(V, CastToCStr(CI->getOperand(1), B));
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
+ if (!isa<PointerType>(CI->getOperand(3)->getType())) return 0;
+
+ Value *Len = EmitStrLen(CI->getOperand(3), B);
+ Value *IncLen = B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1),
+ "leninc");
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(3), IncLen, 1, B);
+
+ // The sprintf result is the unincremented number of bytes in the string.
+ return B.CreateIntCast(Len, CI->getType(), false);
+ }
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'fwrite' Optimizations
+
+struct VISIBILITY_HIDDEN FWriteOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require a pointer, an integer, an integer, a pointer, returning integer.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 4 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<IntegerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getParamType(2)) ||
+ !isa<PointerType>(FT->getParamType(3)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // Get the element size and count.
+ ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getOperand(2));
+ ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getOperand(3));
+ if (!SizeC || !CountC) return 0;
+ uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
+
+ // If this is writing zero records, remove the call (it's a noop).
+ if (Bytes == 0)
+ return ConstantInt::get(CI->getType(), 0);
+
+ // If this is writing one byte, turn it into fputc.
+ if (Bytes == 1) { // fwrite(S,1,1,F) -> fputc(S[0],F)
+ Value *Char = B.CreateLoad(CastToCStr(CI->getOperand(1), B), "char");
+ EmitFPutC(Char, CI->getOperand(4), B);
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'fputs' Optimizations
+
+struct VISIBILITY_HIDDEN FPutsOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two pointers. Also, we can't optimize if return value is used.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !CI->use_empty())
+ return 0;
+
+ // fputs(s,F) --> fwrite(s,1,strlen(s),F)
+ uint64_t Len = GetStringLength(CI->getOperand(1));
+ if (!Len) return false;
+ EmitFWrite(CI->getOperand(1), ConstantInt::get(TD->getIntPtrType(), Len-1),
+ CI->getOperand(2), B);
+ return CI; // Known to have no uses (see above).
+ }
+};
+
+//===---------------------------------------===//
+// 'fprintf' Optimizations
+
+struct VISIBILITY_HIDDEN FPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two fixed paramters as pointers and integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // All the optimizations depend on the format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
+ if (CI->getNumOperands() == 3) {
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
+ return false; // We found a format specifier.
+
+ EmitFWrite(CI->getOperand(2), ConstantInt::get(TD->getIntPtrType(),
+ FormatStr.size()),
+ CI->getOperand(1), B);
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c"
+ // and have an extra operand.
+ if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
+ return 0;
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ // fprintf(F, "%c", chr) --> *(i8*)dst = chr
+ if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
+ EmitFPutC(CI->getOperand(3), CI->getOperand(1), B);
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // fprintf(F, "%s", str) -> fputs(str, F)
+ if (!isa<PointerType>(CI->getOperand(3)->getType()) || !CI->use_empty())
+ return 0;
+ EmitFPutS(CI->getOperand(3), CI->getOperand(1), B);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+
+//===----------------------------------------------------------------------===//
+// SimplifyLibCalls Pass Implementation
+//===----------------------------------------------------------------------===//
+
+namespace {
+ /// This pass optimizes well known library functions from libc and libm.
+ ///
+ class VISIBILITY_HIDDEN SimplifyLibCalls : public FunctionPass {
+ StringMap<LibCallOptimization*> Optimizations;
+ // Miscellaneous LibCall Optimizations
+ ExitOpt Exit;
+ // String and Memory LibCall Optimizations
+ StrCatOpt StrCat; StrChrOpt StrChr; StrCmpOpt StrCmp; StrNCmpOpt StrNCmp;
+ StrCpyOpt StrCpy; StrLenOpt StrLen; MemCmpOpt MemCmp; MemCpyOpt MemCpy;
+ // Math Library Optimizations
+ PowOpt Pow; UnaryDoubleFPOpt UnaryDoubleFP;
+ // Integer Optimizations
+ FFSOpt FFS; IsDigitOpt IsDigit; IsAsciiOpt IsAscii; ToAsciiOpt ToAscii;
+ // Formatting and IO Optimizations
+ SPrintFOpt SPrintF; PrintFOpt PrintF;
+ FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
+ public:
+ static char ID; // Pass identification
+ SimplifyLibCalls() : FunctionPass((intptr_t)&ID) {}
+
+ void InitOptimizations();
+ bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<TargetData>();
+ }
+ };
+ char SimplifyLibCalls::ID = 0;
+} // end anonymous namespace.
+
+static RegisterPass<SimplifyLibCalls>
+X("simplify-libcalls", "Simplify well-known library calls");
+
+// Public interface to the Simplify LibCalls pass.
+FunctionPass *llvm::createSimplifyLibCallsPass() {
+ return new SimplifyLibCalls();
+}
+
+/// Optimizations - Populate the Optimizations map with all the optimizations
+/// we know.
+void SimplifyLibCalls::InitOptimizations() {
+ // Miscellaneous LibCall Optimizations
+ Optimizations["exit"] = &Exit;
+
+ // String and Memory LibCall Optimizations
+ Optimizations["strcat"] = &StrCat;
+ Optimizations["strchr"] = &StrChr;
+ Optimizations["strcmp"] = &StrCmp;
+ Optimizations["strncmp"] = &StrNCmp;
+ Optimizations["strcpy"] = &StrCpy;
+ Optimizations["strlen"] = &StrLen;
+ Optimizations["memcmp"] = &MemCmp;
+ Optimizations["memcpy"] = &MemCpy;
+
+ // Math Library Optimizations
+ Optimizations["powf"] = &Pow;
+ Optimizations["pow"] = &Pow;
+ Optimizations["powl"] = &Pow;
+#ifdef HAVE_FLOORF
+ Optimizations["floor"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_CEILF
+ Optimizations["ceil"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_ROUNDF
+ Optimizations["round"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_RINTF
+ Optimizations["rint"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_NEARBYINTF
+ Optimizations["nearbyint"] = &UnaryDoubleFP;
+#endif
+
+ // Integer Optimizations
+ Optimizations["ffs"] = &FFS;
+ Optimizations["ffsl"] = &FFS;
+ Optimizations["ffsll"] = &FFS;
+ Optimizations["isdigit"] = &IsDigit;
+ Optimizations["isascii"] = &IsAscii;
+ Optimizations["toascii"] = &ToAscii;
+
+ // Formatting and IO Optimizations
+ Optimizations["sprintf"] = &SPrintF;
+ Optimizations["printf"] = &PrintF;
+ Optimizations["fwrite"] = &FWrite;
+ Optimizations["fputs"] = &FPuts;
+ Optimizations["fprintf"] = &FPrintF;
+}
+
+
+/// runOnFunction - Top level algorithm.
+///
+bool SimplifyLibCalls::runOnFunction(Function &F) {
+ if (Optimizations.empty())
+ InitOptimizations();
+
+ const TargetData &TD = getAnalysis<TargetData>();
+
+ IRBuilder Builder;
+
+ bool Changed = false;
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
+ // Ignore non-calls.
+ CallInst *CI = dyn_cast<CallInst>(I++);
+ if (!CI) continue;
+
+ // Ignore indirect calls and calls to non-external functions.
+ Function *Callee = CI->getCalledFunction();
+ if (Callee == 0 || !Callee->isDeclaration() ||
+ !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
+ continue;
+
+ // Ignore unknown calls.
+ const char *CalleeName = Callee->getNameStart();
+ StringMap<LibCallOptimization*>::iterator OMI =
+ Optimizations.find(CalleeName, CalleeName+Callee->getNameLen());
+ if (OMI == Optimizations.end()) continue;
+
+ // Set the builder to the instruction after the call.
+ Builder.SetInsertPoint(BB, I);
+
+ // Try to optimize this call.
+ Value *Result = OMI->second->OptimizeCall(CI, TD, Builder);
+ if (Result == 0) continue;
+
+ // Something changed!
+ Changed = true;
+ ++NumSimplified;
+
+ // Inspect the instruction after the call (which was potentially just
+ // added) next.
+ I = CI; ++I;
+
+ if (CI != Result && !CI->use_empty()) {
+ CI->replaceAllUsesWith(Result);
+ if (!Result->hasName())
+ Result->takeName(CI);
+ }
+ CI->eraseFromParent();
+ }
+ }
+ return Changed;
+}
+
+
+// TODO:
+// Additional cases that we need to add to this file:
+//
+// cbrt:
+// * cbrt(expN(X)) -> expN(x/3)
+// * cbrt(sqrt(x)) -> pow(x,1/6)
+// * cbrt(sqrt(x)) -> pow(x,1/9)
+//
+// cos, cosf, cosl:
+// * cos(-x) -> cos(x)
+//
+// exp, expf, expl:
+// * exp(log(x)) -> x
+//
+// log, logf, logl:
+// * log(exp(x)) -> x
+// * log(x**y) -> y*log(x)
+// * log(exp(y)) -> y*log(e)
+// * log(exp2(y)) -> y*log(2)
+// * log(exp10(y)) -> y*log(10)
+// * log(sqrt(x)) -> 0.5*log(x)
+// * log(pow(x,y)) -> y*log(x)
+//
+// lround, lroundf, lroundl:
+// * lround(cnst) -> cnst'
+//
+// memcmp:
+// * memcmp(x,y,l) -> cnst
+// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
+//
+// memmove:
+// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
+// (if s is a global constant array)
+//
+// pow, powf, powl:
+// * pow(exp(x),y) -> exp(x*y)
+// * pow(sqrt(x),y) -> pow(x,y*0.5)
+// * pow(pow(x,y),z)-> pow(x,y*z)
+//
+// puts:
+// * puts("") -> putchar("\n")
+//
+// round, roundf, roundl:
+// * round(cnst) -> cnst'
+//
+// signbit:
+// * signbit(cnst) -> cnst'
+// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
+//
+// sqrt, sqrtf, sqrtl:
+// * sqrt(expN(x)) -> expN(x*0.5)
+// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
+// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
+//
+// stpcpy:
+// * stpcpy(str, "literal") ->
+// llvm.memcpy(str,"literal",strlen("literal")+1,1)
+// strrchr:
+// * strrchr(s,c) -> reverse_offset_of_in(c,s)
+// (if c is a constant integer and s is a constant string)
+// * strrchr(s1,0) -> strchr(s1,0)
+//
+// strncat:
+// * strncat(x,y,0) -> x
+// * strncat(x,y,0) -> x (if strlen(y) = 0)
+// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
+//
+// strncpy:
+// * strncpy(d,s,0) -> d
+// * strncpy(d,s,l) -> memcpy(d,s,l,1)
+// (if s and l are constants)
+//
+// strpbrk:
+// * strpbrk(s,a) -> offset_in_for(s,a)
+// (if s and a are both constant strings)
+// * strpbrk(s,"") -> 0
+// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
+//
+// strspn, strcspn:
+// * strspn(s,a) -> const_int (if both args are constant)
+// * strspn("",a) -> 0
+// * strspn(s,"") -> 0
+// * strcspn(s,a) -> const_int (if both args are constant)
+// * strcspn("",a) -> 0
+// * strcspn(s,"") -> strlen(a)
+//
+// strstr:
+// * strstr(x,x) -> x
+// * strstr(s1,s2) -> offset_of_s2_in(s1)
+// (if s1 and s2 are constant strings)
+//
+// tan, tanf, tanl:
+// * tan(atan(x)) -> x
+//
+// trunc, truncf, truncl:
+// * trunc(cnst) -> cnst'
+//
+//
projects / oota-llvm.git / commitdiff