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Teach the IR verifier to reject conflicting debug info for function arguments.

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Conflicting debug info for function arguments causes hard-to-debug
assertions in the DWARF backend, so the Verifier should reject it.
For performance reasons this only checks function arguments from
non-inlined debug intrinsics for now.

rdar://problem/30520286

llvm-svn: 295749
This commit is contained in:
Adrian Prantl 2017-02-21 19:03:15 +00:00
parent 0599d58aba
commit 458ca95045
2 changed files with 64 additions and 0 deletions
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38
lib/IR/Verifier.cpp
View File

@ -297,6 +297,9 @@ class Verifier : public InstVisitor<Verifier>, VerifierSupport {
// constant expressions, we can arrive at a particular user many times.
SmallPtrSet<const Value *, 32> GlobalValueVisited;
// Keeps track of duplicate function argument debug info.
SmallVector<const DILocalVariable *, 16> DebugFnArgs;
TBAAVerifier TBAAVerifyHelper;
void checkAtomicMemAccessSize(Type *Ty, const Instruction *I);
@ -498,6 +501,7 @@ private:
void verifySiblingFuncletUnwinds();
void verifyFragmentExpression(const DbgInfoIntrinsic &I);
void verifyFnArgs(const DbgInfoIntrinsic &I);
/// Module-level debug info verification...
void verifyCompileUnits();
@ -1946,6 +1950,8 @@ void Verifier::verifySiblingFuncletUnwinds() {
// visitFunction - Verify that a function is ok.
//
void Verifier::visitFunction(const Function &F) {
DebugFnArgs.clear();
visitGlobalValue(F);
// Check function arguments.
@ -4348,6 +4354,8 @@ void Verifier::visitDbgIntrinsic(StringRef Kind, DbgIntrinsicTy &DII) {
" variable and !dbg attachment",
&DII, BB, F, Var, Var->getScope()->getSubprogram(), Loc,
Loc->getScope()->getSubprogram());
verifyFnArgs(DII);
}
static uint64_t getVariableSize(const DILocalVariable &V) {
@ -4416,6 +4424,36 @@ void Verifier::verifyFragmentExpression(const DbgInfoIntrinsic &I) {
AssertDI(FragSize != VarSize, "fragment covers entire variable", &I, V, E);
}
void Verifier::verifyFnArgs(const DbgInfoIntrinsic &I) {
DILocalVariable *Var;
if (auto *DV = dyn_cast<DbgValueInst>(&I)) {
// For performance reasons only check non-inlined ones.
if (DV->getDebugLoc()->getInlinedAt())
return;
Var = DV->getVariable();
} else {
auto *DD = cast<DbgDeclareInst>(&I);
if (DD->getDebugLoc()->getInlinedAt())
return;
Var = DD->getVariable();
}
AssertDI(Var, "dbg intrinsic without variable");
unsigned ArgNo = Var->getArg();
if (!ArgNo)
return;
// Verify there are no duplicate function argument debug info entries.
// These will cause hard-to-debug assertions in the DWARF backend.
if (DebugFnArgs.size() < ArgNo)
DebugFnArgs.resize(ArgNo, nullptr);
auto *Prev = DebugFnArgs[ArgNo - 1];
DebugFnArgs[ArgNo - 1] = Var;
AssertDI(!Prev || (Prev == Var), "conflicting debug info for argument", &I,
Prev, Var);
}
void Verifier::verifyCompileUnits() {
auto *CUs = M.getNamedMetadata("llvm.dbg.cu");
SmallPtrSet<const Metadata *, 2> Listed;

26
test/Verifier/fnarg-debuginfo.ll Normal file
View File

@ -0,0 +1,26 @@
; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
define void @foo() !dbg !2 {
entry:
%a = alloca i32
; CHECK: conflicting debug info for argument
call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !3, metadata !DIExpression()), !dbg !6
call void @llvm.dbg.declare(metadata i32* %a, metadata !4, metadata !DIExpression()), !dbg !6
ret void, !dbg !6
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!7, !8}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", emissionKind: FullDebug)
!1 = !DIFile(filename: "x.c", directory: "/")
!2 = distinct !DISubprogram(name: "foo", scope: !0, isDefinition: true, unit: !0)
!3 = !DILocalVariable(name: "a", arg: 1, scope: !2, file: !1, line: 1, type: !5)
!4 = !DILocalVariable(name: "b", arg: 1, scope: !2, file: !1, line: 1, type: !5)
!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!6 = !DILocation(line: 1, scope: !2)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 1, !"Debug Info Version", i32 3}