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Strip debug info when inlining into a nodebug function.

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The LLVM backend cannot produce any debug info for an llvm::Function
without a DISubprogram attachment. When inlining a debug-info-carrying
function into a nodebug function, there is therefore no reason to keep
any debug info intrinsic calls or debug locations on the instructions.

This fixes a problem discovered in PR32042.

rdar://problem/30679307

llvm-svn: 296488
This commit is contained in:
Adrian Prantl
2017-02-28 16:58:13 +00:00
parent 431359aa8b
commit 80d0c93436
3 changed files with 70 additions and 15 deletions
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42
llvm/lib/Transforms/Utils/InlineFunction.cpp
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@@ -1343,22 +1343,26 @@ static bool allocaWouldBeStaticInEntry(const AllocaInst *AI ) {
return isa<Constant>(AI->getArraySize()) && !AI->isUsedWithInAlloca();
}
/// Update inlined instructions' line numbers to
/// to encode location where these instructions are inlined.
static void fixupLineNumbers(Function *Fn, Function::iterator FI,
Instruction *TheCall, bool CalleeHasDebugInfo) {
/// Update inlined instructions' line numbers to to encode location where these
/// instructions are inlined. Also strip all debug intrinsics that were inlined
/// into a nodebug function; there is no debug info the backend could produce
/// for a function without a DISubprogram attachment.
static void fixupDebugInfo(Function *Fn, Function::iterator FI,
Instruction *TheCall, bool CalleeHasDebugInfo) {
bool CallerHasDebugInfo = Fn->getSubprogram();
bool StripDebugInfo = !CallerHasDebugInfo && CalleeHasDebugInfo;
SmallVector<DbgInfoIntrinsic *, 8> IntrinsicsToErase;
const DebugLoc &TheCallDL = TheCall->getDebugLoc();
if (!TheCallDL)
return;
auto &Ctx = Fn->getContext();
DILocation *InlinedAtNode = TheCallDL;
DILocation *InlinedAtNode = nullptr;
// Create a unique call site, not to be confused with any other call from the
// same location.
InlinedAtNode = DILocation::getDistinct(
Ctx, InlinedAtNode->getLine(), InlinedAtNode->getColumn(),
InlinedAtNode->getScope(), InlinedAtNode->getInlinedAt());
if (TheCallDL)
InlinedAtNode = DILocation::getDistinct(
Ctx, TheCallDL->getLine(), TheCallDL->getColumn(),
TheCallDL->getScope(), TheCallDL->getInlinedAt());
// Cache the inlined-at nodes as they're built so they are reused, without
// this every instruction's inlined-at chain would become distinct from each
@@ -1368,6 +1372,17 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
for (; FI != Fn->end(); ++FI) {
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
BI != BE; ++BI) {
if (StripDebugInfo) {
// Inlining into a nodebug function.
if (auto *DI = dyn_cast<DbgInfoIntrinsic>(BI))
// Mark dead debug intrinsics for deletion.
IntrinsicsToErase.push_back(DI);
else
// Remove the dangling debug location.
BI->setDebugLoc(DebugLoc());
continue;
}
if (DebugLoc DL = BI->getDebugLoc()) {
BI->setDebugLoc(
updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes));
@@ -1390,6 +1405,9 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
BI->setDebugLoc(TheCallDL);
}
}
for (auto *DI : IntrinsicsToErase)
DI->eraseFromParent();
}
/// Update the block frequencies of the caller after a callee has been inlined.
///
@@ -1710,8 +1728,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
// For 'nodebug' functions, the associated DISubprogram is always null.
// Conservatively avoid propagating the callsite debug location to
// instructions inlined from a function whose DISubprogram is not null.
fixupLineNumbers(Caller, FirstNewBlock, TheCall,
CalledFunc->getSubprogram() != nullptr);
fixupDebugInfo(Caller, FirstNewBlock, TheCall,
CalledFunc->getSubprogram() != nullptr);
// Clone existing noalias metadata if necessary.
CloneAliasScopeMetadata(CS, VMap);