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

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Merged
merged 10 commits into from
Sep 2, 2024
Merged

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

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7a084b4
[DebugInfo][RemoveDIs] Find types hidden in DbgRecords
jmorse Aug 29, 2024
1e5a2cd
claaannngggg fooorrmmaatttt
jmorse Aug 29, 2024
515ab3a
Switch to dyn_cast, get Address too
jmorse Aug 29, 2024
791ce77
Add a #dbg_assign to be enumerated
jmorse Aug 29, 2024
90055ba
clang-format again
jmorse Aug 29, 2024
4eaf585
Allow for empty dbg_assign addresses being null
jmorse Aug 30, 2024
e2a3fe4
clang-format
jmorse Aug 30, 2024
a887cb7
Allow for DIArgLists in the address field of #dbg_assigns
jmorse Aug 30, 2024
0a358b1
The proverbial clang-format
jmorse Aug 30, 2024
792f9b9
Don't access address field on non-dbg-assigns
jmorse Sep 2, 2024
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5 changes: 3 additions & 2 deletions llvm/lib/IR/DebugProgramInstruction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

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12 changes: 12 additions & 0 deletions llvm/lib/IR/TypeFinder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,18 @@ 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 (Value *Addr = DVI->getAddress(); Addr && DVI->isDbgAssign())
incorporateValue(Addr);
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Regarding the latest change to check allow for DIArgList in getAddress: it's not permitted for dbg_declares or dbg_assigns address components to use DIArgList. getAddress returns the first DebugValue operand unless it's a dbg_assign - then it returns the second. The only reason we're seeing an DIArgList pop up in getAddress is because its being called before checking if DVI->isDbgAssign(): some dbg_value with a DIArgList is having getAddress called on it. I thought this would be fine when I wrote the suggestion above but clearly it breaks assumptions.

I think it's probably better to restructure this to:

if (DVI->isDbgAssign())) {
  if (Value *Addr = DVI->getAddress())
    incorporateValue(Addr);
}

And revert the most recent getAddress change- wdyt? Sorry for the additional hassle.

}
}
}
}

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51 changes: 51 additions & 0 deletions llvm/test/DebugInfo/type-finder-w-dbg-records.ll
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@@ -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)
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possibly worth adding dbg_assign and dbg_declare for completeness? (dbg_assign more important here imo, given the extra fields)

#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()
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