//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
-#include "Inliner.h"
+#define DEBUG_TYPE "inline"
#include "llvm/CallingConv.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
-#include "llvm/Function.h"
+#include "llvm/Module.h"
#include "llvm/Type.h"
+#include "llvm/Analysis/CallGraph.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Compiler.h"
#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/Transforms/Utils/InlineCost.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
using namespace llvm;
namespace {
- struct ArgInfo {
- unsigned ConstantWeight;
- unsigned AllocaWeight;
-
- ArgInfo(unsigned CWeight, unsigned AWeight)
- : ConstantWeight(CWeight), AllocaWeight(AWeight) {}
- };
-
- // FunctionInfo - For each function, calculate the size of it in blocks and
- // instructions.
- struct FunctionInfo {
- // NumInsts, NumBlocks - Keep track of how large each function is, which is
- // used to estimate the code size cost of inlining it.
- unsigned NumInsts, NumBlocks;
-
- // ArgumentWeights - Each formal argument of the function is inspected to
- // see if it is used in any contexts where making it a constant or alloca
- // would reduce the code size. If so, we add some value to the argument
- // entry here.
- std::vector<ArgInfo> ArgumentWeights;
-
- FunctionInfo() : NumInsts(0), NumBlocks(0) {}
- /// analyzeFunction - Fill in the current structure with information gleaned
- /// from the specified function.
- void analyzeFunction(Function *F);
- };
-
- class SimpleInliner : public Inliner {
- std::map<const Function*, FunctionInfo> CachedFunctionInfo;
+ class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
+ // Functions that are never inlined
+ SmallPtrSet<const Function*, 16> NeverInline;
+ InlineCostAnalyzer CA;
public:
- int getInlineCost(CallSite CS);
+ SimpleInliner() : Inliner(&ID) {}
+ static char ID; // Pass identification, replacement for typeid
+ int getInlineCost(CallSite CS) {
+ return CA.getInlineCost(CS, NeverInline);
+ }
+ virtual bool doInitialization(CallGraph &CG);
};
+ char SimpleInliner::ID = 0;
RegisterPass<SimpleInliner> X("inline", "Function Integration/Inlining");
}
Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
-// CountCodeReductionForConstant - Figure out an approximation for how many
-// instructions will be constant folded if the specified value is constant.
-//
-static unsigned CountCodeReductionForConstant(Value *V) {
- unsigned Reduction = 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
- if (isa<BranchInst>(*UI))
- Reduction += 40; // Eliminating a conditional branch is a big win
- else if (SwitchInst *SI = dyn_cast<SwitchInst>(*UI))
- // Eliminating a switch is a big win, proportional to the number of edges
- // deleted.
- Reduction += (SI->getNumSuccessors()-1) * 40;
- else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
- // Turning an indirect call into a direct call is a BIG win
- Reduction += CI->getCalledValue() == V ? 500 : 0;
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) {
- // Turning an indirect call into a direct call is a BIG win
- Reduction += II->getCalledValue() == V ? 500 : 0;
- } else {
- // Figure out if this instruction will be removed due to simple constant
- // propagation.
- Instruction &Inst = cast<Instruction>(**UI);
- bool AllOperandsConstant = true;
- for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
- if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
- AllOperandsConstant = false;
- break;
- }
-
- if (AllOperandsConstant) {
- // We will get to remove this instruction...
- Reduction += 7;
-
- // And any other instructions that use it which become constants
- // themselves.
- Reduction += CountCodeReductionForConstant(&Inst);
- }
- }
-
- return Reduction;
-}
-
-// CountCodeReductionForAlloca - Figure out an approximation of how much smaller
-// the function will be if it is inlined into a context where an argument
-// becomes an alloca.
-//
-static unsigned CountCodeReductionForAlloca(Value *V) {
- if (!isa<PointerType>(V->getType())) return 0; // Not a pointer
- unsigned Reduction = 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
- Instruction *I = cast<Instruction>(*UI);
- if (isa<LoadInst>(I) || isa<StoreInst>(I))
- Reduction += 10;
- else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
- // If the GEP has variable indices, we won't be able to do much with it.
- for (Instruction::op_iterator I = GEP->op_begin()+1, E = GEP->op_end();
- I != E; ++I)
- if (!isa<Constant>(*I)) return 0;
- Reduction += CountCodeReductionForAlloca(GEP)+15;
- } else {
- // If there is some other strange instruction, we're not going to be able
- // to do much if we inline this.
- return 0;
- }
- }
-
- return Reduction;
-}
-
-/// analyzeFunction - Fill in the current structure with information gleaned
-/// from the specified function.
-void FunctionInfo::analyzeFunction(Function *F) {
- unsigned NumInsts = 0, NumBlocks = 0;
-
- // Look at the size of the callee. Each basic block counts as 20 units, and
- // each instruction counts as 10.
- for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
- for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
- II != E; ++II) {
- if (isa<DbgInfoIntrinsic>(II)) continue; // Debug intrinsics don't count.
-
- // Noop casts, including ptr <-> int, don't count.
- if (const CastInst *CI = dyn_cast<CastInst>(II)) {
- if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) ||
- isa<PtrToIntInst>(CI))
- continue;
- } else if (const GetElementPtrInst *GEPI =
- dyn_cast<GetElementPtrInst>(II)) {
- // If a GEP has all constant indices, it will probably be folded with
- // a load/store.
- bool AllConstant = true;
- for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i)
- if (!isa<ConstantInt>(GEPI->getOperand(i))) {
- AllConstant = false;
- break;
- }
- if (AllConstant) continue;
- }
-
- ++NumInsts;
- }
-
- ++NumBlocks;
- }
-
- this->NumBlocks = NumBlocks;
- this->NumInsts = NumInsts;
-
- // Check out all of the arguments to the function, figuring out how much
- // code can be eliminated if one of the arguments is a constant.
- for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
- ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I),
- CountCodeReductionForAlloca(I)));
-}
-
-
-// getInlineCost - The heuristic used to determine if we should inline the
-// function call or not.
-//
-int SimpleInliner::getInlineCost(CallSite CS) {
- Instruction *TheCall = CS.getInstruction();
- Function *Callee = CS.getCalledFunction();
- const Function *Caller = TheCall->getParent()->getParent();
-
- // Don't inline a directly recursive call.
- if (Caller == Callee) return 2000000000;
-
- // InlineCost - This value measures how good of an inline candidate this call
- // site is to inline. A lower inline cost make is more likely for the call to
- // be inlined. This value may go negative.
- //
- int InlineCost = 0;
-
- // If there is only one call of the function, and it has internal linkage,
- // make it almost guaranteed to be inlined.
- //
- if (Callee->hasInternalLinkage() && Callee->hasOneUse())
- InlineCost -= 30000;
-
- // If this function uses the coldcc calling convention, prefer not to inline
- // it.
- if (Callee->getCallingConv() == CallingConv::Cold)
- InlineCost += 2000;
-
- // If the instruction after the call, or if the normal destination of the
- // invoke is an unreachable instruction, the function is noreturn. As such,
- // there is little point in inlining this.
- if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
- if (isa<UnreachableInst>(II->getNormalDest()->begin()))
- InlineCost += 10000;
- } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
- InlineCost += 10000;
-
- // Get information about the callee...
- FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
-
- // If we haven't calculated this information yet, do so now.
- if (CalleeFI.NumBlocks == 0)
- CalleeFI.analyzeFunction(Callee);
-
- // Add to the inline quality for properties that make the call valuable to
- // inline. This includes factors that indicate that the result of inlining
- // the function will be optimizable. Currently this just looks at arguments
- // passed into the function.
- //
- unsigned ArgNo = 0;
- for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
- I != E; ++I, ++ArgNo) {
- // Each argument passed in has a cost at both the caller and the callee
- // sides. This favors functions that take many arguments over functions
- // that take few arguments.
- InlineCost -= 20;
-
- // If this is a function being passed in, it is very likely that we will be
- // able to turn an indirect function call into a direct function call.
- if (isa<Function>(I))
- InlineCost -= 100;
-
- // If an alloca is passed in, inlining this function is likely to allow
- // significant future optimization possibilities (like scalar promotion, and
- // scalarization), so encourage the inlining of the function.
- //
- else if (isa<AllocaInst>(I)) {
- if (ArgNo < CalleeFI.ArgumentWeights.size())
- InlineCost -= CalleeFI.ArgumentWeights[ArgNo].AllocaWeight;
-
- // If this is a constant being passed into the function, use the argument
- // weights calculated for the callee to determine how much will be folded
- // away with this information.
- } else if (isa<Constant>(I)) {
- if (ArgNo < CalleeFI.ArgumentWeights.size())
- InlineCost -= CalleeFI.ArgumentWeights[ArgNo].ConstantWeight;
- }
+// doInitialization - Initializes the vector of functions that have been
+// annotated with the noinline attribute.
+bool SimpleInliner::doInitialization(CallGraph &CG) {
+
+ Module &M = CG.getModule();
+
+ // Get llvm.noinline
+ GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
+
+ if (GV == 0)
+ return false;
+
+ // Don't crash on invalid code
+ if (!GV->hasInitializer())
+ return false;
+
+ const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
+
+ if (InitList == 0)
+ return false;
+
+ // Iterate over each element and add to the NeverInline set
+ for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+
+ // Get Source
+ const Constant *Elt = InitList->getOperand(i);
+
+ if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
+ if (CE->getOpcode() == Instruction::BitCast)
+ Elt = CE->getOperand(0);
+
+ // Insert into set of functions to never inline
+ if (const Function *F = dyn_cast<Function>(Elt))
+ NeverInline.insert(F);
}
-
- // Now that we have considered all of the factors that make the call site more
- // likely to be inlined, look at factors that make us not want to inline it.
-
- // Don't inline into something too big, which would make it bigger. Here, we
- // count each basic block as a single unit.
- //
- InlineCost += Caller->size()/20;
-
-
- // Look at the size of the callee. Each basic block counts as 20 units, and
- // each instruction counts as 5.
- InlineCost += CalleeFI.NumInsts*5 + CalleeFI.NumBlocks*20;
- return InlineCost;
+
+ return false;
}
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