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[DebugInfo][RemoveDIs] Find types hidden in DbgRecords (#106547)

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When serialising to textual IR, there can be constant Values referred to
by DbgRecords that don't appear anywhere else, and have types hidden
even deeper in side them. Enumerate these when enumerating all types.

Test by Mikael Holmén.
This commit is contained in:
Jeremy Morse
2024-09-02 11:56:40 +01:00
committed by GitHub
parent 5dcea4628d
commit 25f87f2d70
3 changed files with 68 additions and 2 deletions
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5
llvm/lib/IR/DebugProgramInstruction.cpp
View File

@@ -473,11 +473,12 @@ DbgLabelRecord::createDebugIntrinsic(Module *M,
Value *DbgVariableRecord::getAddress() const {
auto *MD = getRawAddress();
if (auto *V = dyn_cast<ValueAsMetadata>(MD))
if (auto *V = dyn_cast_or_null<ValueAsMetadata>(MD))
return V->getValue();
// When the value goes to null, it gets replaced by an empty MDNode.
assert(!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
assert(!MD ||
!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
return nullptr;
}

14
llvm/lib/IR/TypeFinder.cpp
View File

@@ -88,6 +88,20 @@ void TypeFinder::run(const Module &M, bool onlyNamed) {
for (const auto &MD : MDForInst)
incorporateMDNode(MD.second);
MDForInst.clear();
// Incorporate types hiding in variable-location information.
for (const auto &Dbg : I.getDbgRecordRange()) {
// Pick out records that have Values.
if (const DbgVariableRecord *DVI =
dyn_cast<DbgVariableRecord>(&Dbg)) {
for (Value *V : DVI->location_ops())
incorporateValue(V);
if (DVI->isDbgAssign()) {
if (Value *Addr = DVI->getAddress())
incorporateValue(Addr);
}
}
}
}
}

51
llvm/test/DebugInfo/type-finder-w-dbg-records.ll Normal file
View File

@@ -0,0 +1,51 @@
; RUN: opt --passes=verify %s -o - -S | FileCheck %s
;; Test that the type definitions are discovered when serialising to LLVM-IR,
;; even if they're only present inside a DbgRecord, and thus not normally
;; visible.
; CHECK: %union.anon = type { %struct.a }
; CHECK: %struct.a = type { i32 }
; CHECK: %union.anon2 = type { %struct.a2 }
; CHECK: %struct.a2 = type { i32 }
; ModuleID = 'bbi-98372.ll'
source_filename = "bbi-98372.ll"
%union.anon = type { %struct.a }
%struct.a = type { i32 }
%union.anon2 = type { %struct.a2 }
%struct.a2 = type { i32 }
@d = global [1 x { i16, i16 }] [{ i16, i16 } { i16 0, i16 undef }], align 1
@e = global [1 x { i16, i16 }] [{ i16, i16 } { i16 0, i16 undef }], align 1
define void @f() {
entry:
#dbg_value(ptr getelementptr inbounds ([1 x %union.anon], ptr @d, i32 0, i32 3), !7, !DIExpression(), !14)
#dbg_assign(ptr null, !7, !DIExpression(), !16, ptr getelementptr inbounds ([1 x %union.anon2], ptr @e, i32 0, i32 3), !17, !14)
ret void, !dbg !15
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3, !4, !5}
!llvm.ident = !{!6}
!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "foo.c", directory: "/bar")
!2 = !{i32 7, !"Dwarf Version", i32 4}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{i32 1, !"wchar_size", i32 1}
!5 = !{i32 7, !"frame-pointer", i32 2}
!6 = !{!"clang"}
!7 = !DILocalVariable(name: "f", scope: !8, file: !1, line: 8, type: !12)
!8 = distinct !DISubprogram(name: "e", scope: !1, file: !1, line: 8, type: !9, scopeLine: 8, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !11)
!9 = !DISubroutineType(types: !10)
!10 = !{null}
!11 = !{!7}
!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 16)
!13 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
!14 = !DILocation(line: 0, scope: !8)
!15 = !DILocation(line: 8, column: 28, scope: !8)
!16 = distinct !DIAssignID()
!17 = !DIExpression()