llvm-6502/lib/VMCore/DebugInfoProbe.cpp
Devang Patel 6af531febe Introduce DebugInfoProbe. This is used to monitor how llvm optimizer is treating debugging information.
It generates output that lools like

8 times line number info lost by Scalar Replacement of Aggregates (SSAUp) 
1 times line number info lost by Simplify well-known library calls 
12 times variable info lost by Jump Threading



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127381 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-10 00:21:25 +00:00

238 lines
7.4 KiB
C++

//===-- DebugInfoProbe.cpp - DebugInfo Probe ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements DebugInfoProbe. This probe can be used by a pass
// manager to analyze how optimizer is treating debugging information.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "debuginfoprobe"
#include "llvm/DebugInfoProbe.h"
#include "llvm/Function.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Metadata.h"
#include "llvm/PassManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/DebugLoc.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/StringRef.h"
#include <set>
#include <string>
using namespace llvm;
static cl::opt<bool>
EnableDebugInfoProbe("enable-debug-info-probe", cl::Hidden,
cl::desc("Enable debug info probe"));
// CreateInfoOutputFile - Return a file stream to print our output on.
namespace llvm { extern raw_ostream *CreateInfoOutputFile(); }
//===----------------------------------------------------------------------===//
// DebugInfoProbeImpl - This class implements a interface to monitor
// how an optimization pass is preserving debugging information.
namespace llvm {
class DebugInfoProbeImpl {
public:
DebugInfoProbeImpl() : NumDbgLineLost(0),NumDbgValueLost(0) {}
void initialize(StringRef PName, Function &F);
void finalize(Function &F);
void report();
private:
unsigned NumDbgLineLost, NumDbgValueLost;
std::string PassName;
Function *TheFn;
std::set<unsigned> LineNos;
std::set<MDNode *> DbgVariables;
};
}
//===----------------------------------------------------------------------===//
// DebugInfoProbeImpl
static void collect(Function &F, std::set<unsigned> &Lines) {
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
const DebugLoc &DL = BI->getDebugLoc();
unsigned LineNo = 0;
if (!DL.isUnknown()) {
if (MDNode *N = DL.getInlinedAt(F.getContext()))
LineNo = DebugLoc::getFromDILocation(N).getLine();
else
LineNo = DL.getLine();
Lines.insert(LineNo);
}
}
}
/// initialize - Collect information before running an optimization pass.
void DebugInfoProbeImpl::initialize(StringRef PName, Function &F) {
if (!EnableDebugInfoProbe) return;
PassName = PName;
NumDbgLineLost = 0;
NumDbgValueLost = 0;
LineNos.clear();
DbgVariables.clear();
TheFn = &F;
collect(F, LineNos);
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
if (!isa<DbgInfoIntrinsic>(BI)) continue;
Value *Addr = NULL;
MDNode *Node = NULL;
if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(BI)) {
Addr = DDI->getAddress();
Node = DDI->getVariable();
} else if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
Addr = DVI->getValue();
Node = DVI->getVariable();
}
if (Addr) continue;
DbgVariables.insert(Node);
}
}
/// report - Report findings. This should be invoked after finalize.
void DebugInfoProbeImpl::report() {
if (!EnableDebugInfoProbe) return;
if (NumDbgLineLost || NumDbgValueLost) {
raw_ostream *OutStream = CreateInfoOutputFile();
if (NumDbgLineLost)
*OutStream << NumDbgLineLost
<< "\t times line number info lost by "
<< PassName << "\n";
if (NumDbgValueLost)
*OutStream << NumDbgValueLost
<< "\t times variable info lost by "
<< PassName << "\n";
delete OutStream;
}
}
/// finalize - Collect information after running an optimization pass. This
/// must be used after initialization.
void DebugInfoProbeImpl::finalize(Function &F) {
if (!EnableDebugInfoProbe) return;
std::set<unsigned> LineNos2;
collect(F, LineNos2);
assert (TheFn == &F && "Invalid function to measure!");
for (std::set<unsigned>::iterator I = LineNos.begin(),
E = LineNos.end(); I != E; ++I) {
unsigned LineNo = *I;
if (LineNos2.count(LineNo) == 0) {
DEBUG(dbgs() << "Losing dbg info intrinsic at line " << LineNo << " ");
++NumDbgLineLost;
}
}
std::set<MDNode *>DbgVariables2;
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
if (!isa<DbgInfoIntrinsic>(BI)) continue;
Value *Addr = NULL;
MDNode *Node = NULL;
if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(BI)) {
Addr = DDI->getAddress();
Node = DDI->getVariable();
} else if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
Addr = DVI->getValue();
Node = DVI->getVariable();
}
if (Addr) continue;
DbgVariables2.insert(Node);
}
for (std::set<MDNode *>::iterator I = DbgVariables.begin(),
E = DbgVariables.end(); I != E; ++I) {
if (DbgVariables2.count(*I) == 0) {
DEBUG(dbgs() << "Losing dbg info for variable: ");
DEBUG((*I)->print(dbgs()));
++NumDbgValueLost;
}
}
}
//===----------------------------------------------------------------------===//
// DebugInfoProbe
DebugInfoProbe::DebugInfoProbe() {
pImpl = new DebugInfoProbeImpl();
}
DebugInfoProbe::~DebugInfoProbe() {
delete pImpl;
}
/// initialize - Collect information before running an optimization pass.
void DebugInfoProbe::initialize(StringRef PName, Function &F) {
pImpl->initialize(PName, F);
}
/// finalize - Collect information after running an optimization pass. This
/// must be used after initialization.
void DebugInfoProbe::finalize(Function &F) {
pImpl->finalize(F);
}
/// report - Report findings. This should be invoked after finalize.
void DebugInfoProbe::report() {
pImpl->report();
}
//===----------------------------------------------------------------------===//
// DebugInfoProbeInfo
/// ~DebugInfoProbeInfo - Report data collected by all probes before deleting
/// them.
DebugInfoProbeInfo::~DebugInfoProbeInfo() {
if (!EnableDebugInfoProbe) return;
for (StringMap<DebugInfoProbe*>::iterator I = Probes.begin(),
E = Probes.end(); I != E; ++I) {
I->second->report();
delete I->second;
}
}
/// initialize - Collect information before running an optimization pass.
void DebugInfoProbeInfo::initialize(Pass *P, Function &F) {
if (!EnableDebugInfoProbe) return;
if (P->getAsPMDataManager())
return;
StringMapEntry<DebugInfoProbe *> &Entry =
Probes.GetOrCreateValue(P->getPassName());
DebugInfoProbe *&Probe = Entry.getValue();
if (!Probe)
Probe = new DebugInfoProbe();
Probe->initialize(P->getPassName(), F);
}
/// finalize - Collect information after running an optimization pass. This
/// must be used after initialization.
void DebugInfoProbeInfo::finalize(Pass *P, Function &F) {
if (!EnableDebugInfoProbe) return;
if (P->getAsPMDataManager())
return;
StringMapEntry<DebugInfoProbe *> &Entry =
Probes.GetOrCreateValue(P->getPassName());
DebugInfoProbe *&Probe = Entry.getValue();
assert (Probe && "DebugInfoProbe is not initialized!");
Probe->finalize(F);
}