X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FDeadTypeElimination.cpp;h=58fe7f0a595b7d7014285b8fd4013e9056460dc7;hb=eb53ae4f2dc39e75e725b21b52d77d29cf1c11c9;hp=dc330b29f8a16ab5dbfd72dbd7f4bd35a4cbcb97;hpb=96c466b06ab0c830b07329c1b16037f585ccbe40;p=oota-llvm.git diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp index dc330b29f8a..58fe7f0a595 100644 --- a/lib/Transforms/IPO/DeadTypeElimination.cpp +++ b/lib/Transforms/IPO/DeadTypeElimination.cpp @@ -1,68 +1,41 @@ -//===- 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: -// -// * 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 -// * Fix various problems that we might have in PHI nodes and casts -// * Link uses of 'void %foo(...)' to 'void %foo(sometypes)' -// -// 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/Transforms/IPO.h" #include "llvm/Analysis/FindUsedTypes.h" -#include "TransformInternals.h" #include "llvm/Module.h" #include "llvm/SymbolTable.h" #include "llvm/DerivedTypes.h" -#include "llvm/iPHINode.h" -#include "llvm/iMemory.h" -#include "llvm/iTerminators.h" -#include "llvm/iOther.h" -#include "llvm/Support/CFG.h" -#include "llvm/Pass.h" -#include -#include -using std::vector; -using std::string; -using std::cerr; +#include "Support/StatisticReporter.h" -static const Type *PtrSByte = 0; // 'sbyte*' type +using std::vector; namespace { - struct CleanupGCCOutput : public FunctionPass { - const char *getPassName() const { return "Cleanup GCC Output"; } - + struct DTE : public Pass { // 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. // // Also, initialize instance variables. // - bool doInitialization(Module *M); - - // runOnFunction - This method simplifies the specified function hopefully. - // - bool runOnFunction(Function *F); - - // doPassFinalization - Strip out type names that are unused by the program - bool doFinalization(Module *M); - + bool run(Module &M); + // getAnalysisUsage - This function needs FindUsedTypes to do its job... // virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired(FindUsedTypes::ID); + AU.addRequired(); } }; + RegisterOpt X("deadtypeelim", "Dead Type Elimination"); + Statistic<> NumKilled("deadtypeelim\t- Number of unused typenames removed from symtab"); } -Pass *createCleanupGCCOutputPass() { - return new CleanupGCCOutput(); +Pass *createDeadTypeEliminationPass() { + return new DTE(); } @@ -70,7 +43,7 @@ Pass *createCleanupGCCOutputPass() { // ShouldNukSymtabEntry - Return true if this module level symbol table entry // should be eliminated. // -static inline bool ShouldNukeSymtabEntry(const std::pair &E) { +static inline bool ShouldNukeSymtabEntry(const std::pair&E){ // Nuke all names for primitive types! if (cast(E.second)->isPrimitiveType()) return true; @@ -78,229 +51,22 @@ static inline bool ShouldNukeSymtabEntry(const std::pair &E) { if (const PointerType *PT = dyn_cast(E.second)) if (PT->getElementType()->isPrimitiveType()) return true; - // 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; - return false; } -// doInitialization - 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::doInitialization(Module *M) { - bool Changed = false; - - if (PtrSByte == 0) - PtrSByte = PointerType::get(Type::SByteTy); - - if (M->hasSymbolTable()) { - SymbolTable *ST = M->getSymbolTable(); - - // Check the symbol table for superfluous type entries... - // - // 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; - } - } - } - - return Changed; -} - - -// FixCastsAndPHIs - The LLVM GCC has a tendancy to intermix Cast instructions -// in with the PHI nodes. These cast instructions are potentially there for two -// different reasons: -// -// 1. The cast could be for an early PHI, and be accidentally inserted before -// another PHI node. In this case, the PHI node should be moved to the end -// of the PHI nodes in the basic block. We know that it is this case if -// the source for the cast is a PHI node in this basic block. -// -// 2. If not #1, the cast must be a source argument for one of the PHI nodes -// in the current basic block. If this is the case, the cast should be -// lifted into the basic block for the appropriate predecessor. -// -static inline bool FixCastsAndPHIs(BasicBlock *BB) { - bool Changed = false; - - BasicBlock::iterator InsertPos = BB->begin(); - - // Find the end of the interesting instructions... - while (isa(*InsertPos) || isa(*InsertPos)) ++InsertPos; - - // Back the InsertPos up to right after the last PHI node. - while (InsertPos != BB->begin() && isa(*(InsertPos-1))) --InsertPos; - - // No PHI nodes, quick exit. - if (InsertPos == BB->begin()) return false; - - // Loop over all casts trapped between the PHI's... - BasicBlock::iterator I = BB->begin(); - while (I != InsertPos) { - if (CastInst *CI = dyn_cast(*I)) { // Fix all cast instructions - Value *Src = CI->getOperand(0); - - // Move the cast instruction to the current insert position... - --InsertPos; // New position for cast to go... - std::swap(*InsertPos, *I); // Cast goes down, PHI goes up - - if (isa(Src) && // Handle case #1 - cast(Src)->getParent() == BB) { - // We're done for case #1 - } else { // Handle case #2 - // In case #2, we have to do a few things: - // 1. Remove the cast from the current basic block. - // 2. Identify the PHI node that the cast is for. - // 3. Find out which predecessor the value is for. - // 4. Move the cast to the end of the basic block that it SHOULD be - // - - // Remove the cast instruction from the basic block. The remove only - // invalidates iterators in the basic block that are AFTER the removed - // element. Because we just moved the CastInst to the InsertPos, no - // iterators get invalidated. - // - BB->getInstList().remove(InsertPos); - - // Find the PHI node. Since this cast was generated specifically for a - // PHI node, there can only be a single PHI node using it. - // - assert(CI->use_size() == 1 && "Exactly one PHI node should use cast!"); - PHINode *PN = cast(*CI->use_begin()); - - // Find out which operand of the PHI it is... - unsigned i; - for (i = 0; i < PN->getNumIncomingValues(); ++i) - if (PN->getIncomingValue(i) == CI) - break; - assert(i != PN->getNumIncomingValues() && "PHI doesn't use cast!"); - - // Get the predecessor the value is for... - BasicBlock *Pred = PN->getIncomingBlock(i); - - // Reinsert the cast right before the terminator in Pred. - Pred->getInstList().insert(Pred->end()-1, CI); - } - } else { - ++I; - } - } - - return Changed; -} - -// RefactorPredecessor - When we find out that a basic block is a repeated -// predecessor in a PHI node, we have to refactor the function until there is at -// most a single instance of a basic block in any predecessor list. -// -static inline void RefactorPredecessor(BasicBlock *BB, BasicBlock *Pred) { - Function *M = BB->getParent(); - assert(find(pred_begin(BB), pred_end(BB), Pred) != pred_end(BB) && - "Pred is not a predecessor of BB!"); - - // Create a new basic block, adding it to the end of the function. - BasicBlock *NewBB = new BasicBlock("", M); - - // Add an unconditional branch to BB to the new block. - NewBB->getInstList().push_back(new BranchInst(BB)); - - // Get the terminator that causes a branch to BB from Pred. - TerminatorInst *TI = Pred->getTerminator(); - - // Find the first use of BB in the terminator... - User::op_iterator OI = find(TI->op_begin(), TI->op_end(), BB); - assert(OI != TI->op_end() && "Pred does not branch to BB!!!"); - - // Change the use of BB to point to the new stub basic block - *OI = NewBB; - - // Now we need to loop through all of the PHI nodes in BB and convert their - // first incoming value for Pred to reference the new basic block instead. - // - for (BasicBlock::iterator I = BB->begin(); - PHINode *PN = dyn_cast(*I); ++I) { - int BBIdx = PN->getBasicBlockIndex(Pred); - assert(BBIdx != -1 && "PHI node doesn't have an entry for Pred!"); - - // The value that used to look like it came from Pred now comes from NewBB - PN->setIncomingBlock((unsigned)BBIdx, NewBB); - } -} - - -// runOnFunction - Loop through the function and fix problems with the PHI nodes -// in the current function. The problem is that PHI nodes might exist with -// multiple entries for the same predecessor. GCC sometimes generates code that -// looks like this: -// -// bb7: br bool %cond1004, label %bb8, label %bb8 -// bb8: %reg119 = phi uint [ 0, %bb7 ], [ 1, %bb7 ] -// -// which is completely illegal LLVM code. To compensate for this, we insert -// an extra basic block, and convert the code to look like this: +// 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. // -// bb7: br bool %cond1004, label %bbX, label %bb8 -// bbX: br label bb8 -// bb8: %reg119 = phi uint [ 0, %bbX ], [ 1, %bb7 ] -// -// -bool CleanupGCCOutput::runOnFunction(Function *M) { - bool Changed = false; - // Don't use iterators because invalidation gets messy... - for (unsigned MI = 0; MI < M->size(); ++MI) { - BasicBlock *BB = M->getBasicBlocks()[MI]; - - Changed |= FixCastsAndPHIs(BB); - - if (isa(BB->front())) { - const vector Preds(pred_begin(BB), pred_end(BB)); - - // Handle the problem. Sort the list of predecessors so that it is easy - // to decide whether or not duplicate predecessors exist. - vector SortedPreds(Preds); - sort(SortedPreds.begin(), SortedPreds.end()); - - // Loop over the predecessors, looking for adjacent BB's that are equal. - BasicBlock *LastOne = 0; - for (unsigned i = 0; i < Preds.size(); ++i) { - if (SortedPreds[i] == LastOne) { // Found a duplicate. - RefactorPredecessor(BB, SortedPreds[i]); - Changed = true; - } - LastOne = SortedPreds[i]; - } - } - } - return Changed; -} - -bool CleanupGCCOutput::doFinalization(Module *M) { +bool DTE::run(Module &M) { bool Changed = false; - if (M->hasSymbolTable()) { - SymbolTable *ST = M->getSymbolTable(); + if (SymbolTable *ST = M.getSymbolTable()) { const std::set &UsedTypes = getAnalysis().getTypes(); - // Check the symbol table for superfluous type entries that aren't used in - // the program + // Check the symbol table for superfluous type entries... // // Grab the 'type' plane of the module symbol... SymbolTable::iterator STI = ST->find(Type::TypeTy); @@ -308,221 +74,24 @@ bool CleanupGCCOutput::doFinalization(Module *M) { // Loop over all entries in the type plane... SymbolTable::VarMap &Plane = STI->second; for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();) - if (!UsedTypes.count(cast(PI->second))) { + // If this entry should be unconditionally removed, or if we detect that + // the type is not used, remove it. + // + if (ShouldNukeSymtabEntry(*PI) || + !UsedTypes.count(cast(PI->second))) { #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(); // N^2 algorithms are fun. :( + PI = Plane.begin(); #endif + ++NumKilled; Changed = true; } else { ++PI; } } } - return Changed; -} - - -//===----------------------------------------------------------------------===// -// -// FunctionResolvingPass - Go over the functions that are in the module and -// look for functions that have the same name. More often than not, there will -// be things like: -// void "foo"(...) -// void "foo"(int, int) -// because of the way things are declared in C. If this is the case, patch -// things up. -// -//===----------------------------------------------------------------------===// - -namespace { - struct FunctionResolvingPass : public Pass { - const char *getPassName() const { return "Resolve Functions"; } - - bool run(Module *M); - }; -} - -// ConvertCallTo - Convert a call to a varargs function with no arg types -// specified to a concrete nonvarargs function. -// -static void ConvertCallTo(CallInst *CI, Function *Dest) { - const FunctionType::ParamTypes &ParamTys = - Dest->getFunctionType()->getParamTypes(); - BasicBlock *BB = CI->getParent(); - - // Get an iterator to where we want to insert cast instructions if the - // argument types don't agree. - // - BasicBlock::iterator BBI = find(BB->begin(), BB->end(), CI); - assert(BBI != BB->end() && "CallInst not in parent block?"); - - assert(CI->getNumOperands()-1 == ParamTys.size()&& - "Function calls resolved funny somehow, incompatible number of args"); - - vector Params; - - // Convert all of the call arguments over... inserting cast instructions if - // the types are not compatible. - for (unsigned i = 1; i < CI->getNumOperands(); ++i) { - Value *V = CI->getOperand(i); - - if (V->getType() != ParamTys[i-1]) { // Must insert a cast... - Instruction *Cast = new CastInst(V, ParamTys[i-1]); - BBI = BB->getInstList().insert(BBI, Cast)+1; - V = Cast; - } - - Params.push_back(V); - } - - // Replace the old call instruction with a new call instruction that calls - // the real function. - // - ReplaceInstWithInst(BB->getInstList(), BBI, new CallInst(Dest, Params)); -} - - -bool FunctionResolvingPass::run(Module *M) { - SymbolTable *ST = M->getSymbolTable(); - if (!ST) return false; - - std::map > Functions; - - // Loop over the entries in the symbol table. If an entry is a func pointer, - // then add it to the Functions map. We do a two pass algorithm here to avoid - // problems with iterators getting invalidated if we did a one pass scheme. - // - for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I) - if (const PointerType *PT = dyn_cast(I->first)) - if (isa(PT->getElementType())) { - SymbolTable::VarMap &Plane = I->second; - for (SymbolTable::type_iterator PI = Plane.begin(), PE = Plane.end(); - PI != PE; ++PI) { - const string &Name = PI->first; - Functions[Name].push_back(cast(PI->second)); - } - } - - bool Changed = false; - - // Now we have a list of all functions with a particular name. If there is - // more than one entry in a list, merge the functions together. - // - for (std::map >::iterator I = Functions.begin(), - E = Functions.end(); I != E; ++I) { - vector &Functions = I->second; - Function *Implementation = 0; // Find the implementation - Function *Concrete = 0; - for (unsigned i = 0; i < Functions.size(); ) { - if (!Functions[i]->isExternal()) { // Found an implementation - assert(Implementation == 0 && "Multiple definitions of the same" - " function. Case not handled yet!"); - Implementation = Functions[i]; - } else { - // Ignore functions that are never used so they don't cause spurious - // warnings... here we will actually DCE the function so that it isn't - // used later. - // - if (Functions[i]->use_size() == 0) { - M->getFunctionList().remove(Functions[i]); - delete Functions[i]; - Functions.erase(Functions.begin()+i); - Changed = true; - continue; - } - } - - if (Functions[i] && (!Functions[i]->getFunctionType()->isVarArg())) { - if (Concrete) { // Found two different functions types. Can't choose - Concrete = 0; - break; - } - Concrete = Functions[i]; - } - ++i; - } - - if (Functions.size() > 1) { // Found a multiply defined function... - // We should find exactly one non-vararg function definition, which is - // probably the implementation. Change all of the function definitions - // and uses to use it instead. - // - if (!Concrete) { - cerr << "Warning: Found functions types that are not compatible:\n"; - for (unsigned i = 0; i < Functions.size(); ++i) { - cerr << "\t" << Functions[i]->getType()->getDescription() << " %" - << Functions[i]->getName() << "\n"; - } - cerr << " No linkage of functions named '" << Functions[0]->getName() - << "' performed!\n"; - } else { - for (unsigned i = 0; i < Functions.size(); ++i) - if (Functions[i] != Concrete) { - Function *Old = Functions[i]; - const FunctionType *OldMT = Old->getFunctionType(); - const FunctionType *ConcreteMT = Concrete->getFunctionType(); - bool Broken = false; - - assert(Old->getReturnType() == Concrete->getReturnType() && - "Differing return types not handled yet!"); - assert(OldMT->getParamTypes().size() <= - ConcreteMT->getParamTypes().size() && - "Concrete type must have more specified parameters!"); - - // Check to make sure that if there are specified types, that they - // match... - // - for (unsigned i = 0; i < OldMT->getParamTypes().size(); ++i) - if (OldMT->getParamTypes()[i] != ConcreteMT->getParamTypes()[i]) { - cerr << "Parameter types conflict for" << OldMT - << " and " << ConcreteMT; - Broken = true; - } - if (Broken) break; // Can't process this one! - - - // Attempt to convert all of the uses of the old function to the - // concrete form of the function. If there is a use of the fn - // that we don't understand here we punt to avoid making a bad - // transformation. - // - // At this point, we know that the return values are the same for - // our two functions and that the Old function has no varargs fns - // specified. In otherwords it's just (...) - // - for (unsigned i = 0; i < Old->use_size(); ) { - User *U = *(Old->use_begin()+i); - if (CastInst *CI = dyn_cast(U)) { - // Convert casts directly - assert(CI->getOperand(0) == Old); - CI->setOperand(0, Concrete); - Changed = true; - } else if (CallInst *CI = dyn_cast(U)) { - // Can only fix up calls TO the argument, not args passed in. - if (CI->getCalledValue() == Old) { - ConvertCallTo(CI, Concrete); - Changed = true; - } else { - cerr << "Couldn't cleanup this function call, must be an" - << " argument or something!" << CI; - ++i; - } - } else { - cerr << "Cannot convert use of function: " << U << "\n"; - ++i; - } - } - } - } - } - } return Changed; } - -Pass *createFunctionResolvingPass() { - return new FunctionResolvingPass(); -}