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llvm-for-llvmta/lib/Transforms/Utils/Debugify.cpp

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//===- Debugify.cpp - Attach synthetic debug info to everything -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file This pass attaches synthetic debug info to everything. It can be used
/// to create targeted tests for debug info preservation.
///
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Debugify.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassInstrumentation.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
namespace {
cl::opt<bool> Quiet("debugify-quiet",
cl::desc("Suppress verbose debugify output"));
enum class Level {
Locations,
LocationsAndVariables
};
cl::opt<Level> DebugifyLevel(
"debugify-level", cl::desc("Kind of debug info to add"),
cl::values(clEnumValN(Level::Locations, "locations", "Locations only"),
clEnumValN(Level::LocationsAndVariables, "location+variables",
"Locations and Variables")),
cl::init(Level::LocationsAndVariables));
raw_ostream &dbg() { return Quiet ? nulls() : errs(); }
uint64_t getAllocSizeInBits(Module &M, Type *Ty) {
return Ty->isSized() ? M.getDataLayout().getTypeAllocSizeInBits(Ty) : 0;
}
bool isFunctionSkipped(Function &F) {
return F.isDeclaration() || !F.hasExactDefinition();
}
/// Find the basic block's terminating instruction.
///
/// Special care is needed to handle musttail and deopt calls, as these behave
/// like (but are in fact not) terminators.
Instruction *findTerminatingInstruction(BasicBlock &BB) {
if (auto *I = BB.getTerminatingMustTailCall())
return I;
if (auto *I = BB.getTerminatingDeoptimizeCall())
return I;
return BB.getTerminator();
}
} // end anonymous namespace
bool llvm::applyDebugifyMetadata(
Module &M, iterator_range<Module::iterator> Functions, StringRef Banner,
std::function<bool(DIBuilder &DIB, Function &F)> ApplyToMF) {
// Skip modules with debug info.
if (M.getNamedMetadata("llvm.dbg.cu")) {
dbg() << Banner << "Skipping module with debug info\n";
return false;
}
DIBuilder DIB(M);
LLVMContext &Ctx = M.getContext();
auto *Int32Ty = Type::getInt32Ty(Ctx);
// Get a DIType which corresponds to Ty.
DenseMap<uint64_t, DIType *> TypeCache;
auto getCachedDIType = [&](Type *Ty) -> DIType * {
uint64_t Size = getAllocSizeInBits(M, Ty);
DIType *&DTy = TypeCache[Size];
if (!DTy) {
std::string Name = "ty" + utostr(Size);
DTy = DIB.createBasicType(Name, Size, dwarf::DW_ATE_unsigned);
}
return DTy;
};
unsigned NextLine = 1;
unsigned NextVar = 1;
auto File = DIB.createFile(M.getName(), "/");
auto CU = DIB.createCompileUnit(dwarf::DW_LANG_C, File, "debugify",
/*isOptimized=*/true, "", 0);
// Visit each instruction.
for (Function &F : Functions) {
if (isFunctionSkipped(F))
continue;
bool InsertedDbgVal = false;
auto SPType = DIB.createSubroutineType(DIB.getOrCreateTypeArray(None));
DISubprogram::DISPFlags SPFlags =
DISubprogram::SPFlagDefinition | DISubprogram::SPFlagOptimized;
if (F.hasPrivateLinkage() || F.hasInternalLinkage())
SPFlags |= DISubprogram::SPFlagLocalToUnit;
auto SP = DIB.createFunction(CU, F.getName(), F.getName(), File, NextLine,
SPType, NextLine, DINode::FlagZero, SPFlags);
F.setSubprogram(SP);
// Helper that inserts a dbg.value before \p InsertBefore, copying the
// location (and possibly the type, if it's non-void) from \p TemplateInst.
auto insertDbgVal = [&](Instruction &TemplateInst,
Instruction *InsertBefore) {
std::string Name = utostr(NextVar++);
Value *V = &TemplateInst;
if (TemplateInst.getType()->isVoidTy())
V = ConstantInt::get(Int32Ty, 0);
const DILocation *Loc = TemplateInst.getDebugLoc().get();
auto LocalVar = DIB.createAutoVariable(SP, Name, File, Loc->getLine(),
getCachedDIType(V->getType()),
/*AlwaysPreserve=*/true);
DIB.insertDbgValueIntrinsic(V, LocalVar, DIB.createExpression(), Loc,
InsertBefore);
};
for (BasicBlock &BB : F) {
// Attach debug locations.
for (Instruction &I : BB)
I.setDebugLoc(DILocation::get(Ctx, NextLine++, 1, SP));
if (DebugifyLevel < Level::LocationsAndVariables)
continue;
// Inserting debug values into EH pads can break IR invariants.
if (BB.isEHPad())
continue;
// Find the terminating instruction, after which no debug values are
// attached.
Instruction *LastInst = findTerminatingInstruction(BB);
assert(LastInst && "Expected basic block with a terminator");
// Maintain an insertion point which can't be invalidated when updates
// are made.
BasicBlock::iterator InsertPt = BB.getFirstInsertionPt();
assert(InsertPt != BB.end() && "Expected to find an insertion point");
Instruction *InsertBefore = &*InsertPt;
// Attach debug values.
for (Instruction *I = &*BB.begin(); I != LastInst; I = I->getNextNode()) {
// Skip void-valued instructions.
if (I->getType()->isVoidTy())
continue;
// Phis and EH pads must be grouped at the beginning of the block.
// Only advance the insertion point when we finish visiting these.
if (!isa<PHINode>(I) && !I->isEHPad())
InsertBefore = I->getNextNode();
insertDbgVal(*I, InsertBefore);
InsertedDbgVal = true;
}
}
// Make sure we emit at least one dbg.value, otherwise MachineDebugify may
// not have anything to work with as it goes about inserting DBG_VALUEs.
// (It's common for MIR tests to be written containing skeletal IR with
// empty functions -- we're still interested in debugifying the MIR within
// those tests, and this helps with that.)
if (DebugifyLevel == Level::LocationsAndVariables && !InsertedDbgVal) {
auto *Term = findTerminatingInstruction(F.getEntryBlock());
insertDbgVal(*Term, Term);
}
if (ApplyToMF)
ApplyToMF(DIB, F);
DIB.finalizeSubprogram(SP);
}
DIB.finalize();
// Track the number of distinct lines and variables.
NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.debugify");
auto addDebugifyOperand = [&](unsigned N) {
NMD->addOperand(MDNode::get(
Ctx, ValueAsMetadata::getConstant(ConstantInt::get(Int32Ty, N))));
};
addDebugifyOperand(NextLine - 1); // Original number of lines.
addDebugifyOperand(NextVar - 1); // Original number of variables.
assert(NMD->getNumOperands() == 2 &&
"llvm.debugify should have exactly 2 operands!");
// Claim that this synthetic debug info is valid.
StringRef DIVersionKey = "Debug Info Version";
if (!M.getModuleFlag(DIVersionKey))
M.addModuleFlag(Module::Warning, DIVersionKey, DEBUG_METADATA_VERSION);
return true;
}
static bool applyDebugify(Function &F) {
Module &M = *F.getParent();
auto FuncIt = F.getIterator();
return applyDebugifyMetadata(M, make_range(FuncIt, std::next(FuncIt)),
"FunctionDebugify: ", /*ApplyToMF=*/nullptr);
}
static bool applyDebugify(Module &M) {
return applyDebugifyMetadata(M, M.functions(),
"ModuleDebugify: ", /*ApplyToMF=*/nullptr);
}
bool llvm::stripDebugifyMetadata(Module &M) {
bool Changed = false;
// Remove the llvm.debugify module-level named metadata.
NamedMDNode *DebugifyMD = M.getNamedMetadata("llvm.debugify");
if (DebugifyMD) {
M.eraseNamedMetadata(DebugifyMD);
Changed = true;
}
// Strip out all debug intrinsics and supporting metadata (subprograms, types,
// variables, etc).
Changed |= StripDebugInfo(M);
// Strip out the dead dbg.value prototype.
Function *DbgValF = M.getFunction("llvm.dbg.value");
if (DbgValF) {
assert(DbgValF->isDeclaration() && DbgValF->use_empty() &&
"Not all debug info stripped?");
DbgValF->eraseFromParent();
Changed = true;
}
// Strip out the module-level Debug Info Version metadata.
// FIXME: There must be an easier way to remove an operand from a NamedMDNode.
NamedMDNode *NMD = M.getModuleFlagsMetadata();
if (!NMD)
return Changed;
SmallVector<MDNode *, 4> Flags(NMD->operands());
NMD->clearOperands();
for (MDNode *Flag : Flags) {
MDString *Key = dyn_cast_or_null<MDString>(Flag->getOperand(1));
if (Key->getString() == "Debug Info Version") {
Changed = true;
continue;
}
NMD->addOperand(Flag);
}
// If we left it empty we might as well remove it.
if (NMD->getNumOperands() == 0)
NMD->eraseFromParent();
return Changed;
}
namespace {
/// Return true if a mis-sized diagnostic is issued for \p DVI.
bool diagnoseMisSizedDbgValue(Module &M, DbgValueInst *DVI) {
// The size of a dbg.value's value operand should match the size of the
// variable it corresponds to.
//
// TODO: This, along with a check for non-null value operands, should be
// promoted to verifier failures.
Value *V = DVI->getValue();
if (!V)
return false;
// For now, don't try to interpret anything more complicated than an empty
// DIExpression. Eventually we should try to handle OP_deref and fragments.
if (DVI->getExpression()->getNumElements())
return false;
Type *Ty = V->getType();
uint64_t ValueOperandSize = getAllocSizeInBits(M, Ty);
Optional<uint64_t> DbgVarSize = DVI->getFragmentSizeInBits();
if (!ValueOperandSize || !DbgVarSize)
return false;
bool HasBadSize = false;
if (Ty->isIntegerTy()) {
auto Signedness = DVI->getVariable()->getSignedness();
if (Signedness && *Signedness == DIBasicType::Signedness::Signed)
HasBadSize = ValueOperandSize < *DbgVarSize;
} else {
HasBadSize = ValueOperandSize != *DbgVarSize;
}
if (HasBadSize) {
dbg() << "ERROR: dbg.value operand has size " << ValueOperandSize
<< ", but its variable has size " << *DbgVarSize << ": ";
DVI->print(dbg());
dbg() << "\n";
}
return HasBadSize;
}
bool checkDebugifyMetadata(Module &M,
iterator_range<Module::iterator> Functions,
StringRef NameOfWrappedPass, StringRef Banner,
bool Strip, DebugifyStatsMap *StatsMap) {
// Skip modules without debugify metadata.
NamedMDNode *NMD = M.getNamedMetadata("llvm.debugify");
if (!NMD) {
dbg() << Banner << ": Skipping module without debugify metadata\n";
return false;
}
auto getDebugifyOperand = [&](unsigned Idx) -> unsigned {
return mdconst::extract<ConstantInt>(NMD->getOperand(Idx)->getOperand(0))
->getZExtValue();
};
assert(NMD->getNumOperands() == 2 &&
"llvm.debugify should have exactly 2 operands!");
unsigned OriginalNumLines = getDebugifyOperand(0);
unsigned OriginalNumVars = getDebugifyOperand(1);
bool HasErrors = false;
// Track debug info loss statistics if able.
DebugifyStatistics *Stats = nullptr;
if (StatsMap && !NameOfWrappedPass.empty())
Stats = &StatsMap->operator[](NameOfWrappedPass);
BitVector MissingLines{OriginalNumLines, true};
BitVector MissingVars{OriginalNumVars, true};
for (Function &F : Functions) {
if (isFunctionSkipped(F))
continue;
// Find missing lines.
for (Instruction &I : instructions(F)) {
if (isa<DbgValueInst>(&I) || isa<PHINode>(&I))
continue;
auto DL = I.getDebugLoc();
if (DL && DL.getLine() != 0) {
MissingLines.reset(DL.getLine() - 1);
continue;
}
if (!DL) {
dbg() << "WARNING: Instruction with empty DebugLoc in function ";
dbg() << F.getName() << " --";
I.print(dbg());
dbg() << "\n";
}
}
// Find missing variables and mis-sized debug values.
for (Instruction &I : instructions(F)) {
auto *DVI = dyn_cast<DbgValueInst>(&I);
if (!DVI)
continue;
unsigned Var = ~0U;
(void)to_integer(DVI->getVariable()->getName(), Var, 10);
assert(Var <= OriginalNumVars && "Unexpected name for DILocalVariable");
bool HasBadSize = diagnoseMisSizedDbgValue(M, DVI);
if (!HasBadSize)
MissingVars.reset(Var - 1);
HasErrors |= HasBadSize;
}
}
// Print the results.
for (unsigned Idx : MissingLines.set_bits())
dbg() << "WARNING: Missing line " << Idx + 1 << "\n";
for (unsigned Idx : MissingVars.set_bits())
dbg() << "WARNING: Missing variable " << Idx + 1 << "\n";
// Update DI loss statistics.
if (Stats) {
Stats->NumDbgLocsExpected += OriginalNumLines;
Stats->NumDbgLocsMissing += MissingLines.count();
Stats->NumDbgValuesExpected += OriginalNumVars;
Stats->NumDbgValuesMissing += MissingVars.count();
}
dbg() << Banner;
if (!NameOfWrappedPass.empty())
dbg() << " [" << NameOfWrappedPass << "]";
dbg() << ": " << (HasErrors ? "FAIL" : "PASS") << '\n';
// Strip debugify metadata if required.
if (Strip)
return stripDebugifyMetadata(M);
return false;
}
/// ModulePass for attaching synthetic debug info to everything, used with the
/// legacy module pass manager.
struct DebugifyModulePass : public ModulePass {
bool runOnModule(Module &M) override { return applyDebugify(M); }
DebugifyModulePass() : ModulePass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
static char ID; // Pass identification.
};
/// FunctionPass for attaching synthetic debug info to instructions within a
/// single function, used with the legacy module pass manager.
struct DebugifyFunctionPass : public FunctionPass {
bool runOnFunction(Function &F) override { return applyDebugify(F); }
DebugifyFunctionPass() : FunctionPass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
static char ID; // Pass identification.
};
/// ModulePass for checking debug info inserted by -debugify, used with the
/// legacy module pass manager.
struct CheckDebugifyModulePass : public ModulePass {
bool runOnModule(Module &M) override {
return checkDebugifyMetadata(M, M.functions(), NameOfWrappedPass,
"CheckModuleDebugify", Strip, StatsMap);
}
CheckDebugifyModulePass(bool Strip = false, StringRef NameOfWrappedPass = "",
DebugifyStatsMap *StatsMap = nullptr)
: ModulePass(ID), Strip(Strip), NameOfWrappedPass(NameOfWrappedPass),
StatsMap(StatsMap) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
static char ID; // Pass identification.
private:
bool Strip;
StringRef NameOfWrappedPass;
DebugifyStatsMap *StatsMap;
};
/// FunctionPass for checking debug info inserted by -debugify-function, used
/// with the legacy module pass manager.
struct CheckDebugifyFunctionPass : public FunctionPass {
bool runOnFunction(Function &F) override {
Module &M = *F.getParent();
auto FuncIt = F.getIterator();
return checkDebugifyMetadata(M, make_range(FuncIt, std::next(FuncIt)),
NameOfWrappedPass, "CheckFunctionDebugify",
Strip, StatsMap);
}
CheckDebugifyFunctionPass(bool Strip = false,
StringRef NameOfWrappedPass = "",
DebugifyStatsMap *StatsMap = nullptr)
: FunctionPass(ID), Strip(Strip), NameOfWrappedPass(NameOfWrappedPass),
StatsMap(StatsMap) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
static char ID; // Pass identification.
private:
bool Strip;
StringRef NameOfWrappedPass;
DebugifyStatsMap *StatsMap;
};
} // end anonymous namespace
void llvm::exportDebugifyStats(StringRef Path, const DebugifyStatsMap &Map) {
std::error_code EC;
raw_fd_ostream OS{Path, EC};
if (EC) {
errs() << "Could not open file: " << EC.message() << ", " << Path << '\n';
return;
}
OS << "Pass Name" << ',' << "# of missing debug values" << ','
<< "# of missing locations" << ',' << "Missing/Expected value ratio" << ','
<< "Missing/Expected location ratio" << '\n';
for (const auto &Entry : Map) {
StringRef Pass = Entry.first;
DebugifyStatistics Stats = Entry.second;
OS << Pass << ',' << Stats.NumDbgValuesMissing << ','
<< Stats.NumDbgLocsMissing << ',' << Stats.getMissingValueRatio() << ','
<< Stats.getEmptyLocationRatio() << '\n';
}
}
ModulePass *llvm::createDebugifyModulePass() {
return new DebugifyModulePass();
}
FunctionPass *llvm::createDebugifyFunctionPass() {
return new DebugifyFunctionPass();
}
PreservedAnalyses NewPMDebugifyPass::run(Module &M, ModuleAnalysisManager &) {
applyDebugifyMetadata(M, M.functions(),
"ModuleDebugify: ", /*ApplyToMF*/ nullptr);
return PreservedAnalyses::all();
}
ModulePass *llvm::createCheckDebugifyModulePass(bool Strip,
StringRef NameOfWrappedPass,
DebugifyStatsMap *StatsMap) {
return new CheckDebugifyModulePass(Strip, NameOfWrappedPass, StatsMap);
}
FunctionPass *
llvm::createCheckDebugifyFunctionPass(bool Strip, StringRef NameOfWrappedPass,
DebugifyStatsMap *StatsMap) {
return new CheckDebugifyFunctionPass(Strip, NameOfWrappedPass, StatsMap);
}
PreservedAnalyses NewPMCheckDebugifyPass::run(Module &M,
ModuleAnalysisManager &) {
checkDebugifyMetadata(M, M.functions(), "", "CheckModuleDebugify", false,
nullptr);
return PreservedAnalyses::all();
}
static bool isIgnoredPass(StringRef PassID) {
return isSpecialPass(PassID, {"PassManager", "PassAdaptor",
"AnalysisManagerProxy", "PrintFunctionPass",
"PrintModulePass", "BitcodeWriterPass",
"ThinLTOBitcodeWriterPass", "VerifierPass"});
}
void DebugifyEachInstrumentation::registerCallbacks(
PassInstrumentationCallbacks &PIC) {
PIC.registerBeforeNonSkippedPassCallback([](StringRef P, Any IR) {
if (isIgnoredPass(P))
return;
if (any_isa<const Function *>(IR))
applyDebugify(*const_cast<Function *>(any_cast<const Function *>(IR)));
else if (any_isa<const Module *>(IR))
applyDebugify(*const_cast<Module *>(any_cast<const Module *>(IR)));
});
PIC.registerAfterPassCallback([this](StringRef P, Any IR,
const PreservedAnalyses &PassPA) {
if (isIgnoredPass(P))
return;
if (any_isa<const Function *>(IR)) {
auto &F = *const_cast<Function *>(any_cast<const Function *>(IR));
Module &M = *F.getParent();
auto It = F.getIterator();
checkDebugifyMetadata(M, make_range(It, std::next(It)), P,
"CheckFunctionDebugify", /*Strip=*/true, &StatsMap);
} else if (any_isa<const Module *>(IR)) {
auto &M = *const_cast<Module *>(any_cast<const Module *>(IR));
checkDebugifyMetadata(M, M.functions(), P, "CheckModuleDebugify",
/*Strip=*/true, &StatsMap);
}
});
}
char DebugifyModulePass::ID = 0;
static RegisterPass<DebugifyModulePass> DM("debugify",
"Attach debug info to everything");
char CheckDebugifyModulePass::ID = 0;
static RegisterPass<CheckDebugifyModulePass>
CDM("check-debugify", "Check debug info from -debugify");
char DebugifyFunctionPass::ID = 0;
static RegisterPass<DebugifyFunctionPass> DF("debugify-function",
"Attach debug info to a function");
char CheckDebugifyFunctionPass::ID = 0;
static RegisterPass<CheckDebugifyFunctionPass>
CDF("check-debugify-function", "Check debug info from -debugify-function");
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