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https://github.com/c64scene-ar/llvm-6502.git
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cc838348fc
Thanks to brg for tracking down the problem so precisely! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8568 91177308-0d34-0410-b5e6-96231b3b80d8
190 lines
6.8 KiB
C++
190 lines
6.8 KiB
C++
//===- RaiseAllocations.cpp - Convert %malloc & %free calls to insts ------===//
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//
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// This file defines the RaiseAllocations pass which convert malloc and free
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// calls to malloc and free instructions.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Module.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/iMemory.h"
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#include "llvm/iTerminators.h"
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#include "llvm/iOther.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CallSite.h"
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#include "Support/Statistic.h"
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namespace {
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Statistic<> NumRaised("raiseallocs", "Number of allocations raised");
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// RaiseAllocations - Turn %malloc and %free calls into the appropriate
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// instruction.
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//
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class RaiseAllocations : public Pass {
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Function *MallocFunc; // Functions in the module we are processing
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Function *FreeFunc; // Initialized by doPassInitializationVirt
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public:
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RaiseAllocations() : MallocFunc(0), FreeFunc(0) {}
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// doPassInitialization - For the raise allocations pass, this finds a
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// declaration for malloc and free if they exist.
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//
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void doInitialization(Module &M);
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// run - This method does the actual work of converting instructions over.
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//
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bool run(Module &M);
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};
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RegisterOpt<RaiseAllocations>
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X("raiseallocs", "Raise allocations from calls to instructions");
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} // end anonymous namespace
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// createRaiseAllocationsPass - The interface to this file...
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Pass *createRaiseAllocationsPass() {
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return new RaiseAllocations();
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}
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// If the module has a symbol table, they might be referring to the malloc and
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// free functions. If this is the case, grab the method pointers that the
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// module is using.
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//
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// Lookup %malloc and %free in the symbol table, for later use. If they don't
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// exist, or are not external, we do not worry about converting calls to that
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// function into the appropriate instruction.
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//
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void RaiseAllocations::doInitialization(Module &M) {
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const FunctionType *MallocType = // Get the type for malloc
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FunctionType::get(PointerType::get(Type::SByteTy),
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std::vector<const Type*>(1, Type::ULongTy), false);
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const FunctionType *FreeType = // Get the type for free
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FunctionType::get(Type::VoidTy,
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std::vector<const Type*>(1, PointerType::get(Type::SByteTy)),
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false);
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// Get Malloc and free prototypes if they exist!
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MallocFunc = M.getFunction("malloc", MallocType);
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FreeFunc = M.getFunction("free" , FreeType);
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// Check to see if the prototype is wrong, giving us sbyte*(uint) * malloc
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// This handles the common declaration of: 'void *malloc(unsigned);'
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if (MallocFunc == 0) {
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MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
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std::vector<const Type*>(1, Type::UIntTy), false);
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MallocFunc = M.getFunction("malloc", MallocType);
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}
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// Check to see if the prototype is missing, giving us sbyte*(...) * malloc
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// This handles the common declaration of: 'void *malloc();'
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if (MallocFunc == 0) {
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MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
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std::vector<const Type*>(), true);
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MallocFunc = M.getFunction("malloc", MallocType);
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}
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// Check to see if the prototype was forgotten, giving us void (...) * free
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// This handles the common forward declaration of: 'void free();'
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if (FreeFunc == 0) {
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FreeType = FunctionType::get(Type::VoidTy, std::vector<const Type*>(),true);
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FreeFunc = M.getFunction("free", FreeType);
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}
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// One last try, check to see if we can find free as 'int (...)* free'. This
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// handles the case where NOTHING was declared.
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if (FreeFunc == 0) {
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FreeType = FunctionType::get(Type::IntTy, std::vector<const Type*>(),true);
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FreeFunc = M.getFunction("free", FreeType);
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}
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// Don't mess with locally defined versions of these functions...
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if (MallocFunc && !MallocFunc->isExternal()) MallocFunc = 0;
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if (FreeFunc && !FreeFunc->isExternal()) FreeFunc = 0;
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}
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// run - Transform calls into instructions...
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//
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bool RaiseAllocations::run(Module &M) {
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// Find the malloc/free prototypes...
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doInitialization(M);
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bool Changed = false;
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// First, process all of the malloc calls...
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if (MallocFunc) {
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std::vector<User*> Users(MallocFunc->use_begin(), MallocFunc->use_end());
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while (!Users.empty()) {
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if (Instruction *I = dyn_cast<Instruction>(Users.back())) {
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CallSite CS = CallSite::get(I);
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if (CS.getInstruction() && CS.getCalledFunction() == MallocFunc &&
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CS.arg_begin() != CS.arg_end()) {
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Value *Source = *CS.arg_begin();
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// If no prototype was provided for malloc, we may need to cast the
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// source size.
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if (Source->getType() != Type::UIntTy)
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Source = new CastInst(Source, Type::UIntTy, "MallocAmtCast", I);
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std::string Name(I->getName()); I->setName("");
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MallocInst *MI = new MallocInst(Type::SByteTy, Source, Name, I);
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I->replaceAllUsesWith(MI);
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// If the old instruction was an invoke, add an unconditional branch
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// before the invoke, which will become the new terminator.
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if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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new BranchInst(II->getNormalDest(), I);
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// Delete the old call site
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MI->getParent()->getInstList().erase(I);
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Changed = true;
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++NumRaised;
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}
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}
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Users.pop_back();
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}
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}
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// Next, process all free calls...
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if (FreeFunc) {
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std::vector<User*> Users(FreeFunc->use_begin(), FreeFunc->use_end());
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while (!Users.empty()) {
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if (Instruction *I = dyn_cast<Instruction>(Users.back())) {
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CallSite CS = CallSite::get(I);
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if (CS.getInstruction() && CS.getCalledFunction() == FreeFunc &&
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CS.arg_begin() != CS.arg_end()) {
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// If no prototype was provided for free, we may need to cast the
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// source pointer. This should be really uncommon, but it's necessary
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// just in case we are dealing with wierd code like this:
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// free((long)ptr);
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//
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Value *Source = *CS.arg_begin();
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if (!isa<PointerType>(Source->getType()))
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Source = new CastInst(Source, PointerType::get(Type::SByteTy),
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"FreePtrCast", I);
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new FreeInst(Source, I);
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// If the old instruction was an invoke, add an unconditional branch
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// before the invoke, which will become the new terminator.
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if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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new BranchInst(II->getNormalDest(), I);
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// Delete the old call site
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I->getParent()->getInstList().erase(I);
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Changed = true;
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++NumRaised;
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}
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}
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Users.pop_back();
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}
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}
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return Changed;
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}
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