diff options
| -rw-r--r-- | lib/Transforms/IPO/DeadTypeElimination.cpp | 245 |
1 files changed, 203 insertions, 42 deletions
diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp index 19e32c07c5..a8f64700a7 100644 --- a/lib/Transforms/IPO/DeadTypeElimination.cpp +++ b/lib/Transforms/IPO/DeadTypeElimination.cpp @@ -20,11 +20,202 @@ #include "llvm/DerivedTypes.h" #include "llvm/iOther.h" #include "llvm/iMemory.h" +#include <map> +#include <algorithm> 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; +} + + +// 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<Value*> 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 method. + // + ReplaceInstWithInst(BB->getInstList(), BBI, new CallInst(Dest, Params)); +} + + +// 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<string, vector<Method*> > 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<PointerType>(I->first)) + if (const MethodType *MT = dyn_cast<MethodType>(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<Method>(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<string, vector<Method*> >::iterator I = Methods.begin(), + E = Methods.end(); I != E; ++I) { + vector<Method*> &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 <retty> (...) + // + for (unsigned i = 0; i < Old->use_size(); ) { + User *U = *(Old->use_begin()+i); + if (CastInst *CI = dyn_cast<CastInst>(U)) { + // Convert casts directly + assert(CI->getOperand(0) == Old); + CI->setOperand(0, Concrete); + Changed = true; + } else if (CallInst *CI = dyn_cast<CallInst>(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; +} + + +// ShouldNukSymtabEntry - Return true if this module level symbol table entry +// should be eliminated. +// static inline bool ShouldNukeSymtabEntry(const pair<string, Value*> &E) { // Nuke all names for primitive types! if (cast<Type>(E.second)->isPrimitiveType()) return true; @@ -36,7 +227,6 @@ static inline bool ShouldNukeSymtabEntry(const pair<string, Value*> &E) { 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. @@ -52,6 +242,18 @@ bool CleanupGCCOutput::doPassInitialization(Module *M) { 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. @@ -96,47 +298,6 @@ bool CleanupGCCOutput::doPassInitialization(Module *M) { return Changed; } -// 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; -} - - -// 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; -} - // doOneCleanupPass - Do one pass over the input method, fixing stuff up. // |