mirror of
https://github.com/c64scene-ar/llvm-6502.git
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136 lines
4.2 KiB
C++
136 lines
4.2 KiB
C++
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//===-- ARMGlobalMerge.cpp - Internal globals merging --------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "arm-global-merge"
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#include "ARM.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/Attributes.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetLowering.h"
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using namespace llvm;
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namespace {
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class VISIBILITY_HIDDEN ARMGlobalMerge : public FunctionPass {
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/// TLI - Keep a pointer of a TargetLowering to consult for determining
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/// target type sizes.
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const TargetLowering *TLI;
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std::vector<GlobalVariable*> InternalGlobals;
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public:
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static char ID; // Pass identification, replacement for typeid.
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explicit ARMGlobalMerge(const TargetLowering *tli)
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: FunctionPass(&ID), TLI(tli) {}
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virtual bool doInitialization(Module &M);
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virtual bool runOnFunction(Function& F);
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const char *getPassName() const {
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return "Merge internal globals";
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}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesCFG();
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FunctionPass::getAnalysisUsage(AU);
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}
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struct GlobalCmp {
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const TargetData *TD;
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GlobalCmp(const TargetData *td):
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TD(td) { };
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bool operator() (const GlobalVariable* GV1,
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const GlobalVariable* GV2) {
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const Type* Ty1 = cast<PointerType>(GV1->getType())->getElementType();
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const Type* Ty2 = cast<PointerType>(GV2->getType())->getElementType();
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return (TD->getTypeAllocSize(Ty1) <
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TD->getTypeAllocSize(Ty2));
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}
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};
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};
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} // end anonymous namespace
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char ARMGlobalMerge::ID = 0;
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#define MAX_OFFSET 4095
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bool ARMGlobalMerge::doInitialization(Module& M) {
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const TargetData *TD = TLI->getTargetData();
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for (Module::global_iterator I = M.global_begin(),
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E = M.global_end(); I != E; ++I) {
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// FIXME: Can we just grab all 'local' vars here?
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// Won't we break some semantics?
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if (I->hasInternalLinkage() &&
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TD->getTypeAllocSize(I->getType()) < MAX_OFFSET)
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InternalGlobals.push_back(I);
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}
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// FIXME: Find better heuristics
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std::stable_sort(InternalGlobals.begin(), InternalGlobals.end(),
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GlobalCmp(TD));
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const Type *Int32Ty = Type::getInt32Ty(M.getContext());
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for (size_t i = 0, e = InternalGlobals.size(); i != e; ) {
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size_t j = 0;
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uint64_t MergedSize = 0;
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std::vector<const Type*> Tys;
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std::vector<Constant*> Inits;
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for (j = i; MergedSize < MAX_OFFSET && j != e; ++j) {
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const Type* Ty =
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cast<PointerType>(InternalGlobals[j]->getType())->getElementType();
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Tys.push_back(Ty);
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Inits.push_back(InternalGlobals[j]->getInitializer());
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MergedSize += TD->getTypeAllocSize(Ty);
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}
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StructType* MergedTy = StructType::get(M.getContext(), Tys);
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Constant* MergedInit = ConstantStruct::get(MergedTy, Inits);
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// FIXME: Should we handle constants and 'normal' globals separately?
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GlobalVariable* MergedGV = new GlobalVariable(M, MergedTy, false,
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GlobalValue::InternalLinkage,
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MergedInit, "merged");
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for (size_t k = i; k < j; ++k) {
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SmallVector<Constant*, 2> Idx;
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Idx.push_back(ConstantInt::get(Int32Ty, 0));
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Idx.push_back(ConstantInt::get(Int32Ty, k-i));
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Constant* GEP =
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ConstantExpr::getInBoundsGetElementPtr(MergedGV,
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&Idx[0], Idx.size());
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InternalGlobals[k]->replaceAllUsesWith(GEP);
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}
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i = j;
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}
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return true;
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}
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bool ARMGlobalMerge::runOnFunction(Function& F) {
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return false;
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}
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FunctionPass *llvm::createARMGlobalMergePass(const TargetLowering *tli) {
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return new ARMGlobalMerge(tli);
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}
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