-//===- CleanupGCCOutput.cpp - Cleanup GCC Output ----------------------------=//
+//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
//
-// This pass is used to cleanup the output of GCC. GCC's output is
-// unneccessarily gross for a couple of reasons. This pass does the following
-// things to try to clean it up:
+// The LLVM Compiler Infrastructure
//
-// * Eliminate names for GCC types that we know can't be needed by the user.
-// - Eliminate names for types that are unused in the entire translation unit
-// but only if they do not name a structure type!
-// - Replace calls to 'sbyte *%malloc(uint)' and 'void %free(sbyte *)' with
-// malloc and free instructions.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
-// Note: This code produces dead declarations, it is a good idea to run DCE
-// after this pass.
+//===----------------------------------------------------------------------===//
+//
+// This pass is used to cleanup the output of GCC. It eliminate names for types
+// that are unused in the entire translation unit, using the FindUsedTypes pass.
//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/CleanupGCCOutput.h"
-#include "llvm/SymbolTable.h"
+#define DEBUG_TYPE "deadtypeelim"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Analysis/FindUsedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/TypeSymbolTable.h"
#include "llvm/DerivedTypes.h"
-#include "llvm/iOther.h"
-#include "llvm/iMemory.h"
-
-static const Type *PtrArrSByte = 0; // '[sbyte]*' type
-static const Type *PtrSByte = 0; // 'sbyte*' type
-
-
-static inline bool ShouldNukeSymtabEntry(const pair<string, Value*> &E) {
- // Nuke all names for primitive types!
- if (cast<Type>(E.second)->isPrimitiveType()) return true;
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Compiler.h"
+using namespace llvm;
- // The only types that could contain .'s in the program are things generated
- // by GCC itself, including "complex.float" and friends. Nuke them too.
- if (E.first.find('.') != string::npos) return true;
+STATISTIC(NumKilled, "Number of unused typenames removed from symtab");
- return false;
-}
+namespace {
+ struct VISIBILITY_HIDDEN DTE : public ModulePass {
+ static char ID; // Pass identification, replacement for typeid
+ DTE() : ModulePass((intptr_t)&ID) {}
-
-// doPassInitialization - For this pass, it removes global symbol table
-// entries for primitive types. These are never used for linking in GCC and
-// they make the output uglier to look at, so we nuke them.
-//
-bool CleanupGCCOutput::doPassInitialization(Module *M) {
- bool Changed = false;
-
- if (PtrArrSByte == 0) {
- PtrArrSByte = PointerType::get(ArrayType::get(Type::SByteTy));
- PtrSByte = PointerType::get(Type::SByteTy);
- }
-
- if (M->hasSymbolTable()) {
- SymbolTable *ST = M->getSymbolTable();
-
- // Lookup %malloc and %free in the symbol table, for later use. If they
- // don't exist, or are not external, we do not worry about converting calls
- // to that function into the appropriate instruction.
+ // doPassInitialization - For this pass, it removes global symbol table
+ // entries for primitive types. These are never used for linking in GCC and
+ // they make the output uglier to look at, so we nuke them.
//
- const PointerType *MallocType = // Get the type for malloc
- PointerType::get(MethodType::get(PointerType::get(Type::SByteTy),
- vector<const Type*>(1, Type::UIntTy), false));
- Malloc = cast_or_null<Method>(ST->lookup(MallocType, "malloc"));
- if (Malloc && !Malloc->isExternal())
- Malloc = 0; // Don't mess with locally defined versions of the fn
-
- const PointerType *FreeType = // Get the type for free
- PointerType::get(MethodType::get(Type::VoidTy,
- vector<const Type*>(1, PointerType::get(Type::SByteTy)), false));
- Free = cast_or_null<Method>(ST->lookup(FreeType, "free"));
- if (Free && !Free->isExternal())
- Free = 0; // Don't mess with locally defined versions of the fn
-
+ // Also, initialize instance variables.
+ //
+ bool runOnModule(Module &M);
- // Check the symbol table for superfluous type entries...
+ // getAnalysisUsage - This function needs FindUsedTypes to do its job...
//
- // Grab the 'type' plane of the module symbol...
- SymbolTable::iterator STI = ST->find(Type::TypeTy);
- if (STI != ST->end()) {
- // Loop over all entries in the type plane...
- SymbolTable::VarMap &Plane = STI->second;
- for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();)
- if (ShouldNukeSymtabEntry(*PI)) { // Should we remove this entry?
-#if MAP_IS_NOT_BRAINDEAD
- PI = Plane.erase(PI); // STD C++ Map should support this!
-#else
- Plane.erase(PI); // Alas, GCC 2.95.3 doesn't *SIGH*
- PI = Plane.begin();
-#endif
- Changed = true;
- } else {
- ++PI;
- }
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<FindUsedTypes>();
}
- }
-
- return Changed;
+ };
+ char DTE::ID = 0;
+ RegisterPass<DTE> X("deadtypeelim", "Dead Type Elimination");
}
-// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI)
-// with a value, then remove and delete the original instruction.
-//
-static void ReplaceInstWithValue(BasicBlock::InstListType &BIL,
- BasicBlock::iterator &BI, Value *V) {
- Instruction *I = *BI;
- // Replaces all of the uses of the instruction with uses of the value
- I->replaceAllUsesWith(V);
-
- // Remove the unneccesary instruction now...
- BIL.remove(BI);
-
- // Make sure to propogate a name if there is one already...
- if (I->hasName() && !V->hasName())
- V->setName(I->getName(), BIL.getParent()->getSymbolTable());
-
- // Remove the dead instruction now...
- delete I;
+ModulePass *llvm::createDeadTypeEliminationPass() {
+ return new DTE();
}
-// ReplaceInstWithInst - Replace the instruction specified by BI with the
-// instruction specified by I. The original instruction is deleted and BI is
-// updated to point to the new instruction.
+// ShouldNukeSymtabEntry - Return true if this module level symbol table entry
+// should be eliminated.
//
-static void ReplaceInstWithInst(BasicBlock::InstListType &BIL,
- BasicBlock::iterator &BI, Instruction *I) {
- assert(I->getParent() == 0 &&
- "ReplaceInstWithInst: Instruction already inserted into basic block!");
-
- // Insert the new instruction into the basic block...
- BI = BIL.insert(BI, I)+1;
+static inline bool ShouldNukeSymtabEntry(const Type *Ty){
+ // Nuke all names for primitive types!
+ if (Ty->isPrimitiveType() || Ty->isInteger())
+ return true;
- // Replace all uses of the old instruction, and delete it.
- ReplaceInstWithValue(BIL, BI, I);
+ // Nuke all pointers to primitive types as well...
+ if (const PointerType *PT = dyn_cast<PointerType>(Ty))
+ if (PT->getElementType()->isPrimitiveType() ||
+ PT->getElementType()->isInteger())
+ return true;
- // Reexamine the instruction just inserted next time around the cleanup pass
- // loop.
- --BI;
+ return false;
}
-
-// doOneCleanupPass - Do one pass over the input method, fixing stuff up.
+// run - For this pass, it removes global symbol table entries for primitive
+// types. These are never used for linking in GCC and they make the output
+// uglier to look at, so we nuke them. Also eliminate types that are never used
+// in the entire program as indicated by FindUsedTypes.
//
-bool CleanupGCCOutput::doOneCleanupPass(Method *M) {
+bool DTE::runOnModule(Module &M) {
bool Changed = false;
- for (Method::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI) {
- BasicBlock *BB = *MI;
- BasicBlock::InstListType &BIL = BB->getInstList();
- for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
- Instruction *I = *BI;
-
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (CI->getCalledValue() == Malloc) { // Replace call to malloc?
- MallocInst *MallocI = new MallocInst(PtrArrSByte, CI->getOperand(1),
- CI->getName());
- CI->setName("");
- BI = BIL.insert(BI, MallocI)+1;
- ReplaceInstWithInst(BIL, BI, new CastInst(MallocI, PtrSByte));
- Changed = true;
- continue; // Skip the ++BI
- } else if (CI->getCalledValue() == Free) { // Replace call to free?
- ReplaceInstWithInst(BIL, BI, new FreeInst(CI->getOperand(1)));
- Changed = true;
- continue; // Skip the ++BI
- }
- }
-
- ++BI;
+ TypeSymbolTable &ST = M.getTypeSymbolTable();
+ std::set<const Type *> UsedTypes = getAnalysis<FindUsedTypes>().getTypes();
+
+ // Check the symbol table for superfluous type entries...
+ //
+ // Grab the 'type' plane of the module symbol...
+ TypeSymbolTable::iterator TI = ST.begin();
+ TypeSymbolTable::iterator TE = ST.end();
+ while ( TI != TE ) {
+ // If this entry should be unconditionally removed, or if we detect that
+ // the type is not used, remove it.
+ const Type *RHS = TI->second;
+ if (ShouldNukeSymtabEntry(RHS) || !UsedTypes.count(RHS)) {
+ ST.remove(TI++);
+ ++NumKilled;
+ Changed = true;
+ } else {
+ ++TI;
+ // We only need to leave one name for each type.
+ UsedTypes.erase(RHS);
}
}
return Changed;
}
-
-
-
-// doPerMethodWork - This method simplifies the specified method hopefully.
-//
-bool CleanupGCCOutput::doPerMethodWork(Method *M) {
- bool Changed = false;
- while (doOneCleanupPass(M)) Changed = true;
- return Changed;
-}
+// vim: sw=2
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