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[DebugInfo][RemoveDIs] Instrument MergeFunctions for DPValues #80974

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merged 3 commits into from
Feb 7, 2024
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[DebugInfo][RemoveDIs] Instrument MergeFunctions for DPValues #80974

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7cb1cba
[DebugInfo][RemoveDIs] Instrument MergeFunctions for DPValues
jmorse Feb 7, 2024
e1086fa
Remember to add some test coverage
jmorse Feb 7, 2024
09a73ec
Stephen-format
jmorse Feb 7, 2024
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187 changes: 118 additions & 69 deletions llvm/lib/Transforms/IPO/MergeFunctions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -256,15 +256,20 @@ class MergeFunctions {

/// Fill PDIUnrelatedWL with instructions from the entry block that are
/// unrelated to parameter related debug info.
/// \param PDPVUnrelatedWL The equivalent non-intrinsic debug records.
void filterInstsUnrelatedToPDI(BasicBlock *GEntryBlock,
std::vector<Instruction *> &PDIUnrelatedWL);
std::vector<Instruction *> &PDIUnrelatedWL,
std::vector<DPValue *> &PDPVUnrelatedWL);

/// Erase the rest of the CFG (i.e. barring the entry block).
void eraseTail(Function *G);

/// Erase the instructions in PDIUnrelatedWL as they are unrelated to the
/// parameter debug info, from the entry block.
void eraseInstsUnrelatedToPDI(std::vector<Instruction *> &PDIUnrelatedWL);
/// \param PDPVUnrelatedWL contains the equivalent set of non-instruction
/// debug-info records.
void eraseInstsUnrelatedToPDI(std::vector<Instruction *> &PDIUnrelatedWL,
std::vector<DPValue *> &PDPVUnrelatedWL);

/// Replace G with a simple tail call to bitcast(F). Also (unless
/// MergeFunctionsPDI holds) replace direct uses of G with bitcast(F),
Expand Down Expand Up @@ -506,7 +511,8 @@ static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) {
// Erase the instructions in PDIUnrelatedWL as they are unrelated to the
// parameter debug info, from the entry block.
void MergeFunctions::eraseInstsUnrelatedToPDI(
std::vector<Instruction *> &PDIUnrelatedWL) {
std::vector<Instruction *> &PDIUnrelatedWL,
std::vector<DPValue *> &PDPVUnrelatedWL) {
LLVM_DEBUG(
dbgs() << " Erasing instructions (in reverse order of appearance in "
"entry block) unrelated to parameter debug info from entry "
Expand All @@ -519,6 +525,16 @@ void MergeFunctions::eraseInstsUnrelatedToPDI(
I->eraseFromParent();
PDIUnrelatedWL.pop_back();
}

while (!PDPVUnrelatedWL.empty()) {
DPValue *DPV = PDPVUnrelatedWL.back();
LLVM_DEBUG(dbgs() << " Deleting DPValue ");
LLVM_DEBUG(DPV->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
DPV->eraseFromParent();
PDPVUnrelatedWL.pop_back();
}

LLVM_DEBUG(dbgs() << " } // Done erasing instructions unrelated to parameter "
"debug info from entry block. \n");
}
Expand Down Expand Up @@ -547,75 +563,99 @@ void MergeFunctions::eraseTail(Function *G) {
// The rest are unrelated to debug info for the parameters; fill up
// PDIUnrelatedWL with such instructions.
void MergeFunctions::filterInstsUnrelatedToPDI(
BasicBlock *GEntryBlock, std::vector<Instruction *> &PDIUnrelatedWL) {
BasicBlock *GEntryBlock, std::vector<Instruction *> &PDIUnrelatedWL,
std::vector<DPValue *> &PDPVUnrelatedWL) {
std::set<Instruction *> PDIRelated;
for (BasicBlock::iterator BI = GEntryBlock->begin(), BIE = GEntryBlock->end();
BI != BIE; ++BI) {
if (auto *DVI = dyn_cast<DbgValueInst>(&*BI)) {
LLVM_DEBUG(dbgs() << " Deciding: ");
LLVM_DEBUG(BI->print(dbgs()));
std::set<DPValue *> PDPVRelated;

// Work out whether a dbg.value intrinsic or an equivalent DPValue is a
// parameter to be preserved.
auto ExamineDbgValue = [](auto *DbgVal, auto &Container) {
LLVM_DEBUG(dbgs() << " Deciding: ");
LLVM_DEBUG(DbgVal->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
DILocalVariable *DILocVar = DbgVal->getVariable();
if (DILocVar->isParameter()) {
LLVM_DEBUG(dbgs() << " Include (parameter): ");
LLVM_DEBUG(DbgVal->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
DILocalVariable *DILocVar = DVI->getVariable();
if (DILocVar->isParameter()) {
LLVM_DEBUG(dbgs() << " Include (parameter): ");
LLVM_DEBUG(BI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(&*BI);
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(BI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else if (auto *DDI = dyn_cast<DbgDeclareInst>(&*BI)) {
LLVM_DEBUG(dbgs() << " Deciding: ");
LLVM_DEBUG(BI->print(dbgs()));
Container.insert(DbgVal);
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(DbgVal->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
DILocalVariable *DILocVar = DDI->getVariable();
if (DILocVar->isParameter()) {
LLVM_DEBUG(dbgs() << " Parameter: ");
LLVM_DEBUG(DILocVar->print(dbgs()));
AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress());
if (AI) {
LLVM_DEBUG(dbgs() << " Processing alloca users: ");
LLVM_DEBUG(dbgs() << "\n");
for (User *U : AI->users()) {
if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (Value *Arg = SI->getValueOperand()) {
if (isa<Argument>(Arg)) {
LLVM_DEBUG(dbgs() << " Include: ");
LLVM_DEBUG(AI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(AI);
LLVM_DEBUG(dbgs() << " Include (parameter): ");
LLVM_DEBUG(SI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(SI);
LLVM_DEBUG(dbgs() << " Include: ");
LLVM_DEBUG(BI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(&*BI);
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(SI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
}
};

auto ExamineDbgDeclare = [&PDIRelated](auto *DbgDecl, auto &Container) {
LLVM_DEBUG(dbgs() << " Deciding: ");
LLVM_DEBUG(DbgDecl->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
DILocalVariable *DILocVar = DbgDecl->getVariable();
if (DILocVar->isParameter()) {
LLVM_DEBUG(dbgs() << " Parameter: ");
LLVM_DEBUG(DILocVar->print(dbgs()));
AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DbgDecl->getAddress());
if (AI) {
LLVM_DEBUG(dbgs() << " Processing alloca users: ");
LLVM_DEBUG(dbgs() << "\n");
for (User *U : AI->users()) {
if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (Value *Arg = SI->getValueOperand()) {
if (isa<Argument>(Arg)) {
LLVM_DEBUG(dbgs() << " Include: ");
LLVM_DEBUG(AI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(AI);
LLVM_DEBUG(dbgs() << " Include (parameter): ");
LLVM_DEBUG(SI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIRelated.insert(SI);
LLVM_DEBUG(dbgs() << " Include: ");
LLVM_DEBUG(DbgDecl->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
Container.insert(DbgDecl);
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(SI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else {
LLVM_DEBUG(dbgs() << " Defer: ");
LLVM_DEBUG(U->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else {
LLVM_DEBUG(dbgs() << " Defer: ");
LLVM_DEBUG(U->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else {
LLVM_DEBUG(dbgs() << " Delete (alloca NULL): ");
LLVM_DEBUG(BI->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(BI->print(dbgs()));
LLVM_DEBUG(dbgs() << " Delete (alloca NULL): ");
LLVM_DEBUG(DbgDecl->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
} else {
LLVM_DEBUG(dbgs() << " Delete (!parameter): ");
LLVM_DEBUG(DbgDecl->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
};

for (BasicBlock::iterator BI = GEntryBlock->begin(), BIE = GEntryBlock->end();
BI != BIE; ++BI) {
// Examine DPValues as they happen "before" the instruction. Are they
// connected to parameters?
for (DPValue &DPV : BI->getDbgValueRange()) {
if (DPV.isDbgValue() || DPV.isDbgAssign()) {
ExamineDbgValue(&DPV, PDPVRelated);
} else {
assert(DPV.isDbgDeclare());
ExamineDbgDeclare(&DPV, PDPVRelated);
}
}

if (auto *DVI = dyn_cast<DbgValueInst>(&*BI)) {
ExamineDbgValue(DVI, PDIRelated);
} else if (auto *DDI = dyn_cast<DbgDeclareInst>(&*BI)) {
ExamineDbgDeclare(DDI, PDIRelated);
} else if (BI->isTerminator() && &*BI == GEntryBlock->getTerminator()) {
LLVM_DEBUG(dbgs() << " Will Include Terminator: ");
LLVM_DEBUG(BI->print(dbgs()));
Expand All @@ -630,17 +670,25 @@ void MergeFunctions::filterInstsUnrelatedToPDI(
LLVM_DEBUG(
dbgs()
<< " Report parameter debug info related/related instructions: {\n");
for (Instruction &I : *GEntryBlock) {
if (PDIRelated.find(&I) == PDIRelated.end()) {

auto IsPDIRelated = [](auto *Rec, auto &Container, auto &UnrelatedCont) {
if (Container.find(Rec) == Container.end()) {
LLVM_DEBUG(dbgs() << " !PDIRelated: ");
LLVM_DEBUG(I.print(dbgs()));
LLVM_DEBUG(Rec->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
PDIUnrelatedWL.push_back(&I);
UnrelatedCont.push_back(Rec);
} else {
LLVM_DEBUG(dbgs() << " PDIRelated: ");
LLVM_DEBUG(I.print(dbgs()));
LLVM_DEBUG(Rec->print(dbgs()));
LLVM_DEBUG(dbgs() << "\n");
}
};

// Collect the set of unrelated instructions and debug records.
for (Instruction &I : *GEntryBlock) {
for (auto &DPV : I.getDbgValueRange())
IsPDIRelated(&DPV, PDPVRelated, PDPVUnrelatedWL);
IsPDIRelated(&I, PDIRelated, PDIUnrelatedWL);
}
LLVM_DEBUG(dbgs() << " }\n");
}
Expand Down Expand Up @@ -680,6 +728,7 @@ static void copyMetadataIfPresent(Function *From, Function *To, StringRef Key) {
void MergeFunctions::writeThunk(Function *F, Function *G) {
BasicBlock *GEntryBlock = nullptr;
std::vector<Instruction *> PDIUnrelatedWL;
std::vector<DPValue *> PDPVUnrelatedWL;
BasicBlock *BB = nullptr;
Function *NewG = nullptr;
if (MergeFunctionsPDI) {
Expand All @@ -691,7 +740,7 @@ void MergeFunctions::writeThunk(Function *F, Function *G) {
dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related "
"debug info for "
<< G->getName() << "() {\n");
filterInstsUnrelatedToPDI(GEntryBlock, PDIUnrelatedWL);
filterInstsUnrelatedToPDI(GEntryBlock, PDIUnrelatedWL, PDPVUnrelatedWL);
GEntryBlock->getTerminator()->eraseFromParent();
BB = GEntryBlock;
} else {
Expand Down Expand Up @@ -740,7 +789,7 @@ void MergeFunctions::writeThunk(Function *F, Function *G) {
<< G->getName() << "()\n");
}
eraseTail(G);
eraseInstsUnrelatedToPDI(PDIUnrelatedWL);
eraseInstsUnrelatedToPDI(PDIUnrelatedWL, PDPVUnrelatedWL);
LLVM_DEBUG(
dbgs() << "} // End of parameter related debug info filtering for: "
<< G->getName() << "()\n");
Expand Down
4 changes: 4 additions & 0 deletions llvm/test/Transforms/MergeFunc/mergefunc-preserve-debug-info.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,10 @@
; RUN: opt -passes='default<O0>,mergefunc' -S -mergefunc-preserve-debug-info < %s | FileCheck %s --check-prefix=OPTIMIZATION_LEVEL_0
; RUN: opt -passes='default<O2>,mergefunc' -S -mergefunc-preserve-debug-info < %s | FileCheck %s --check-prefix=OPTIMIZATION_LEVEL_2

;; Does this continue to work under non-intrinsic debug-info?
; RUN: opt -passes='default<O0>,mergefunc' -S -mergefunc-preserve-debug-info < %s --try-experimental-debuginfo-iterators | FileCheck %s --check-prefix=OPTIMIZATION_LEVEL_0
; RUN: opt -passes='default<O2>,mergefunc' -S -mergefunc-preserve-debug-info < %s --try-experimental-debuginfo-iterators | FileCheck %s --check-prefix=OPTIMIZATION_LEVEL_2

; Preserve debug info in thunks under -passes=mergefunc -mergefunc-preserve-debug-info
;
; We test that:
Expand Down