llvm-6502/lib/Transforms/Instrumentation/EdgeProfiling.cpp
Reid Spencer 9133fe2895 Apply the VISIBILITY_HIDDEN field to the remaining anonymous classes in
the Transforms library. This reduces debug library size by 132 KB, debug
binary size by 376 KB, and reduces link time for llvm tools slightly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33939 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-05 23:32:05 +00:00

98 lines
3.8 KiB
C++

//===- EdgeProfiling.cpp - Insert counters for edge 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 edge profiling.
// Edge profiling can give a reasonable approximation of the hot paths through a
// program, and is used for a wide variety of program transformations.
//
// Note that this implementation is very naive. We insert a counter for *every*
// edge in the program, instead of using control flow information to prune the
// number of counters inserted.
//
//===----------------------------------------------------------------------===//
#include "ProfilingUtils.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Streams.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Instrumentation.h"
#include <set>
using namespace llvm;
namespace {
class VISIBILITY_HIDDEN EdgeProfiler : public ModulePass {
bool runOnModule(Module &M);
};
RegisterPass<EdgeProfiler> X("insert-edge-profiling",
"Insert instrumentation for edge profiling");
}
ModulePass *llvm::createEdgeProfilerPass() { return new EdgeProfiler(); }
bool EdgeProfiler::runOnModule(Module &M) {
Function *Main = M.getFunction("main");
if (Main == 0) {
cerr << "WARNING: cannot insert edge profiling into a module"
<< " with no main function!\n";
return false; // No main, no instrumentation!
}
std::set<BasicBlock*> BlocksToInstrument;
unsigned NumEdges = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
// Keep track of which blocks need to be instrumented. We don't want to
// instrument blocks that are added as the result of breaking critical
// edges!
BlocksToInstrument.insert(BB);
NumEdges += BB->getTerminator()->getNumSuccessors();
}
const Type *ATy = ArrayType::get(Type::Int32Ty, NumEdges);
GlobalVariable *Counters =
new GlobalVariable(ATy, false, GlobalValue::InternalLinkage,
Constant::getNullValue(ATy), "EdgeProfCounters", &M);
// Instrument all of the edges...
unsigned i = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
if (BlocksToInstrument.count(BB)) { // Don't instrument inserted blocks
// Okay, we have to add a counter of each outgoing edge. If the
// outgoing edge is not critical don't split it, just insert the counter
// in the source or destination of the edge.
TerminatorInst *TI = BB->getTerminator();
for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s) {
// If the edge is critical, split it.
SplitCriticalEdge(TI, s, this);
// Okay, we are guaranteed that the edge is no longer critical. If we
// only have a single successor, insert the counter in this block,
// otherwise insert it in the successor block.
if (TI->getNumSuccessors() == 0) {
// Insert counter at the start of the block
IncrementCounterInBlock(BB, i++, Counters);
} else {
// Insert counter at the start of the block
IncrementCounterInBlock(TI->getSuccessor(s), i++, Counters);
}
}
}
// Add the initialization call to main.
InsertProfilingInitCall(Main, "llvm_start_edge_profiling", Counters);
return true;
}