X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FDeadTypeElimination.cpp;h=58fe7f0a595b7d7014285b8fd4013e9056460dc7;hb=eb53ae4f2dc39e75e725b21b52d77d29cf1c11c9;hp=a8f64700a7a4027aacd2063307d0204526cbcef2;hpb=b6b26921e3a6e0375b76e17e67d8a87dc34bda58;p=oota-llvm.git diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp index a8f64700a7a..58fe7f0a595 100644 --- a/lib/Transforms/IPO/DeadTypeElimination.cpp +++ b/lib/Transforms/IPO/DeadTypeElimination.cpp @@ -1,277 +1,70 @@ -//===- 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 -// 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. -// -// 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 "llvm/Module.h" #include "llvm/SymbolTable.h" #include "llvm/DerivedTypes.h" -#include "llvm/iOther.h" -#include "llvm/iMemory.h" -#include -#include - -static const Type *PtrArrSByte = 0; // '[sbyte]*' type -static const Type *PtrSByte = 0; // 'sbyte*' type - - -// 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; -} +#include "Support/StatisticReporter.h" +using std::vector; -// 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. -// -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; - - // Replace all uses of the old instruction, and delete it. - ReplaceInstWithValue(BIL, BI, I); - - // Reexamine the instruction just inserted next time around the cleanup pass - // loop. - --BI; -} - - - -// ConvertCallTo - Convert a call to a varargs function with no arg types -// specified to a concrete nonvarargs method. -// -static void ConvertCallTo(CallInst *CI, Method *Dest) { - const MethodType::ParamTypes &ParamTys = - Dest->getMethodType()->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()&& - "Method 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); +namespace { + 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 run(Module &M); - 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; + // getAnalysisUsage - This function needs FindUsedTypes to do its job... + // + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequired(); } - - Params.push_back(V); - } - - // Replace the old call instruction with a new call instruction that calls - // the real method. - // - ReplaceInstWithInst(BB->getInstList(), BBI, new CallInst(Dest, Params)); + }; + RegisterOpt X("deadtypeelim", "Dead Type Elimination"); + Statistic<> NumKilled("deadtypeelim\t- Number of unused typenames removed from symtab"); } - -// PatchUpMethodReferences - Go over the methods that are in the module and -// look for methods 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. -// -static bool PatchUpMethodReferences(SymbolTable *ST) { - map > Methods; - - // Loop over the entries in the symbol table. If an entry is a method pointer, - // then add it to the Methods 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 (const MethodType *MT = dyn_cast(PT->getValueType())) { - SymbolTable::VarMap &Plane = I->second; - for (SymbolTable::type_iterator PI = Plane.begin(), PE = Plane.end(); - PI != PE; ++PI) { - const string &Name = PI->first; - Method *M = cast(PI->second); - Methods[Name].push_back(M); - } - } - - bool Changed = false; - - // Now we have a list of all methods with a particular name. If there is more - // than one entry in a list, merge the methods together. - // - for (map >::iterator I = Methods.begin(), - E = Methods.end(); I != E; ++I) { - vector &Methods = I->second; - if (Methods.size() > 1) { // Found a multiply defined method. - Method *Implementation = 0; // Find the implementation - Method *Concrete = 0; - for (unsigned i = 0; i < Methods.size(); ++i) { - if (!Methods[i]->isExternal()) { // Found an implementation - assert(Concrete == 0 && "Multiple definitions of the same method. " - "Case not handled yet!"); - Implementation = Methods[i]; - } - - if (!Methods[i]->getMethodType()->isVarArg()) { - assert(Concrete == 0 && "Multiple concrete method types!"); - Concrete = Methods[i]; - } - } - - // We should find exactly one non-vararg method definition, which is - // probably the implementation. Change all of the method definitions - // and uses to use it instead. - // - assert(Concrete && "Multiple varargs defns found?"); - for (unsigned i = 0; i < Methods.size(); ++i) - if (Methods[i] != Concrete) { - Method *Old = Methods[i]; - assert(Old->getReturnType() == Concrete->getReturnType() && - "Differing return types not handled yet!"); - assert(Old->getMethodType()->getParamTypes().size() == 0 && - "Cannot handle varargs fn's with specified element types!"); - - // Attempt to convert all of the uses of the old method to the - // concrete form of the method. If there is a use of the method 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 method has no varargs methods - // 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 method: " << U << endl; - ++i; - } - } - } - } - } - - return Changed; +Pass *createDeadTypeEliminationPass() { + return new DTE(); } + // ShouldNukSymtabEntry - Return true if this module level symbol table entry // should be eliminated. // -static inline bool ShouldNukeSymtabEntry(const pair &E) { +static inline bool ShouldNukeSymtabEntry(const std::pair&E){ // Nuke all names for primitive types! if (cast(E.second)->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; + // Nuke all pointers to primitive types as well... + if (const PointerType *PT = dyn_cast(E.second)) + if (PT->getElementType()->isPrimitiveType()) return true; return false; } -// 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. +// 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::doPassInitialization(Module *M) { +bool DTE::run(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(); - - // Go over the methods that are in the module and look for methods that have - // the same name. More often than not, there will be things like: - // void "foo"(...) and void "foo"(int, int) because of the way things are - // declared in C. If this is the case, patch things up. - // - Changed |= PatchUpMethodReferences(ST); - - - // If the module has a symbol table, they might be referring to the malloc - // and free functions. If this is the case, grab the method pointers that - // the module is using. - // - // 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. - // - const PointerType *MallocType = // Get the type for malloc - PointerType::get(MethodType::get(PointerType::get(Type::SByteTy), - vector(1, Type::UIntTy), false)); - Malloc = cast_or_null(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(1, PointerType::get(Type::SByteTy)), false)); - Free = cast_or_null(ST->lookup(FreeType, "free")); - if (Free && !Free->isExternal()) - Free = 0; // Don't mess with locally defined versions of the fn - + if (SymbolTable *ST = M.getSymbolTable()) { + const std::set &UsedTypes = + getAnalysis().getTypes(); // Check the symbol table for superfluous type entries... // @@ -281,13 +74,18 @@ bool CleanupGCCOutput::doPassInitialization(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 (ShouldNukeSymtabEntry(*PI)) { // Should we remove this entry? + // 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(); #endif + ++NumKilled; Changed = true; } else { ++PI; @@ -297,49 +95,3 @@ bool CleanupGCCOutput::doPassInitialization(Module *M) { return Changed; } - - -// doOneCleanupPass - Do one pass over the input method, fixing stuff up. -// -bool CleanupGCCOutput::doOneCleanupPass(Method *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(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; - } - } - - 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; -}