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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9903 91177308-0d34-0410-b5e6-96231b3b80d8
188 lines
6.6 KiB
C++
188 lines
6.6 KiB
C++
//===- BlockProfiling.cpp - Insert counters for block profiling -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass instruments the specified program with counters for basic block or
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// function profiling. This is the most basic form of profiling, which can tell
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// which blocks are hot, but cannot reliably detect hot paths through the CFG.
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// Block profiling counts the number of times each basic block executes, and
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// function profiling counts the number of times each function is called.
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//
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// Note that this implementation is very naive. Control equivalent regions of
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// the CFG should not require duplicate counters, but we do put duplicate
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// counters in.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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namespace llvm {
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static void insertInitializationCall(Function *MainFn, const char *FnName,
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GlobalValue *Array) {
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const Type *ArgVTy = PointerType::get(PointerType::get(Type::SByteTy));
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const Type *UIntPtr = PointerType::get(Type::UIntTy);
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Module &M = *MainFn->getParent();
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Function *InitFn = M.getOrInsertFunction(FnName, Type::VoidTy, Type::IntTy,
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ArgVTy, UIntPtr, Type::UIntTy, 0);
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// This could force argc and argv into programs that wouldn't otherwise have
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// them, but instead we just pass null values in.
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std::vector<Value*> Args(4);
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Args[0] = Constant::getNullValue(Type::IntTy);
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Args[1] = Constant::getNullValue(ArgVTy);
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// Skip over any allocas in the entry block.
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BasicBlock *Entry = MainFn->begin();
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BasicBlock::iterator InsertPos = Entry->begin();
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while (isa<AllocaInst>(InsertPos)) ++InsertPos;
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Function::aiterator AI;
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switch (MainFn->asize()) {
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default:
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case 2:
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AI = MainFn->abegin(); ++AI;
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if (AI->getType() != ArgVTy) {
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Args[1] = new CastInst(AI, ArgVTy, "argv.cast", InsertPos);
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} else {
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Args[1] = AI;
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}
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case 1:
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AI = MainFn->abegin();
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if (AI->getType() != Type::IntTy) {
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Args[0] = new CastInst(AI, Type::IntTy, "argc.cast", InsertPos);
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} else {
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Args[0] = AI;
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}
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case 0:
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break;
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}
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ConstantPointerRef *ArrayCPR = ConstantPointerRef::get(Array);
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std::vector<Constant*> GEPIndices(2, Constant::getNullValue(Type::LongTy));
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Args[2] = ConstantExpr::getGetElementPtr(ArrayCPR, GEPIndices);
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unsigned NumElements =
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cast<ArrayType>(Array->getType()->getElementType())->getNumElements();
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Args[3] = ConstantUInt::get(Type::UIntTy, NumElements);
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new CallInst(InitFn, Args, "", InsertPos);
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}
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static void IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
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ConstantPointerRef *CounterArray) {
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// Insert the increment after any alloca or PHI instructions...
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BasicBlock::iterator InsertPos = BB->begin();
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while (isa<AllocaInst>(InsertPos) || isa<PHINode>(InsertPos))
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++InsertPos;
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// Create the getelementptr constant expression
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std::vector<Constant*> Indices(2);
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Indices[0] = Constant::getNullValue(Type::LongTy);
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Indices[1] = ConstantSInt::get(Type::LongTy, CounterNum);
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Constant *ElementPtr = ConstantExpr::getGetElementPtr(CounterArray, Indices);
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// Load, increment and store the value back.
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Value *OldVal = new LoadInst(ElementPtr, "OldFuncCounter", InsertPos);
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Value *NewVal = BinaryOperator::create(Instruction::Add, OldVal,
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ConstantInt::get(Type::UIntTy, 1),
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"NewFuncCounter", InsertPos);
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new StoreInst(NewVal, ElementPtr, InsertPos);
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}
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namespace {
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class FunctionProfiler : public Pass {
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bool run(Module &M);
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};
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RegisterOpt<FunctionProfiler> X("insert-function-profiling",
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"Insert instrumentation for function profiling");
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}
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bool FunctionProfiler::run(Module &M) {
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Function *Main = M.getMainFunction();
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if (Main == 0) {
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std::cerr << "WARNING: cannot insert function profiling into a module"
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<< " with no main function!\n";
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return false; // No main, no instrumentation!
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}
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unsigned NumFunctions = 0;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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if (!I->isExternal())
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++NumFunctions;
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const Type *ATy = ArrayType::get(Type::UIntTy, NumFunctions);
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GlobalVariable *Counters =
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new GlobalVariable(ATy, false, GlobalValue::InternalLinkage,
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Constant::getNullValue(ATy), "FuncProfCounters", &M);
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ConstantPointerRef *CounterCPR = ConstantPointerRef::get(Counters);
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// Instrument all of the functions...
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unsigned i = 0;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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if (!I->isExternal())
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// Insert counter at the start of the function
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IncrementCounterInBlock(I->begin(), i++, CounterCPR);
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// Add the initialization call to main.
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insertInitializationCall(Main, "llvm_start_func_profiling", Counters);
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return true;
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}
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namespace {
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class BlockProfiler : public Pass {
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bool run(Module &M);
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};
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RegisterOpt<BlockProfiler> Y("insert-block-profiling",
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"Insert instrumentation for block profiling");
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}
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bool BlockProfiler::run(Module &M) {
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Function *Main = M.getMainFunction();
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if (Main == 0) {
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std::cerr << "WARNING: cannot insert block profiling into a module"
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<< " with no main function!\n";
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return false; // No main, no instrumentation!
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}
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unsigned NumBlocks = 0;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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NumBlocks += I->size();
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const Type *ATy = ArrayType::get(Type::UIntTy, NumBlocks);
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GlobalVariable *Counters =
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new GlobalVariable(ATy, false, GlobalValue::InternalLinkage,
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Constant::getNullValue(ATy), "BlockProfCounters", &M);
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ConstantPointerRef *CounterCPR = ConstantPointerRef::get(Counters);
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// Instrument all of the blocks...
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unsigned i = 0;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
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// Insert counter at the start of the block
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IncrementCounterInBlock(BB, i++, CounterCPR);
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// Add the initialization call to main.
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insertInitializationCall(Main, "llvm_start_block_profiling", Counters);
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return true;
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}
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} // End llvm namespace
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