llvm-6502/lib/Transforms/Instrumentation/BlockProfiling.cpp
2004-03-08 17:06:13 +00:00

111 lines
3.8 KiB
C++

//===- BlockProfiling.cpp - Insert counters for block profiling -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass instruments the specified program with counters for basic block or
// function profiling. This is the most basic form of profiling, which can tell
// which blocks are hot, but cannot reliably detect hot paths through the CFG.
// Block profiling counts the number of times each basic block executes, and
// function profiling counts the number of times each function is called.
//
// Note that this implementation is very naive. Control equivalent regions of
// the CFG should not require duplicate counters, but we do put duplicate
// counters in.
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "ProfilingUtils.h"
using namespace llvm;
namespace {
class FunctionProfiler : public Pass {
bool run(Module &M);
};
RegisterOpt<FunctionProfiler> X("insert-function-profiling",
"Insert instrumentation for function profiling");
}
bool FunctionProfiler::run(Module &M) {
Function *Main = M.getMainFunction();
if (Main == 0) {
std::cerr << "WARNING: cannot insert function profiling into a module"
<< " with no main function!\n";
return false; // No main, no instrumentation!
}
unsigned NumFunctions = 0;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
++NumFunctions;
const Type *ATy = ArrayType::get(Type::UIntTy, NumFunctions);
GlobalVariable *Counters =
new GlobalVariable(ATy, false, GlobalValue::InternalLinkage,
Constant::getNullValue(ATy), "FuncProfCounters", &M);
ConstantPointerRef *CounterCPR = ConstantPointerRef::get(Counters);
// Instrument all of the functions...
unsigned i = 0;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
// Insert counter at the start of the function
IncrementCounterInBlock(I->begin(), i++, CounterCPR);
// Add the initialization call to main.
InsertProfilingInitCall(Main, "llvm_start_func_profiling", Counters);
return true;
}
namespace {
class BlockProfiler : public Pass {
bool run(Module &M);
};
RegisterOpt<BlockProfiler> Y("insert-block-profiling",
"Insert instrumentation for block profiling");
}
bool BlockProfiler::run(Module &M) {
Function *Main = M.getMainFunction();
if (Main == 0) {
std::cerr << "WARNING: cannot insert block profiling into a module"
<< " with no main function!\n";
return false; // No main, no instrumentation!
}
unsigned NumBlocks = 0;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
NumBlocks += I->size();
const Type *ATy = ArrayType::get(Type::UIntTy, NumBlocks);
GlobalVariable *Counters =
new GlobalVariable(ATy, false, GlobalValue::InternalLinkage,
Constant::getNullValue(ATy), "BlockProfCounters", &M);
ConstantPointerRef *CounterCPR = ConstantPointerRef::get(Counters);
// Instrument all of the blocks...
unsigned i = 0;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
// Insert counter at the start of the block
IncrementCounterInBlock(BB, i++, CounterCPR);
// Add the initialization call to main.
InsertProfilingInitCall(Main, "llvm_start_block_profiling", Counters);
return true;
}