[llvm] r363952 - Store a pointer to the return value in a static alloca and let the debugger use that
Amy Huang via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 20 10:15:22 PDT 2019
Author: akhuang
Date: Thu Jun 20 10:15:21 2019
New Revision: 363952
URL: http://llvm.org/viewvc/llvm-project?rev=363952&view=rev
Log:
Store a pointer to the return value in a static alloca and let the debugger use that
as the variable address for NRVO variables.
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D63361
Added:
llvm/trunk/test/DebugInfo/COFF/nrvo.ll
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=363952&r1=363951&r2=363952&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Thu Jun 20 10:15:21 2019
@@ -1142,9 +1142,15 @@ void CodeViewDebug::collectVariableInfoF
// If the variable has an attached offset expression, extract it.
// FIXME: Try to handle DW_OP_deref as well.
int64_t ExprOffset = 0;
- if (VI.Expr)
- if (!VI.Expr->extractIfOffset(ExprOffset))
+ bool Deref = false;
+ if (VI.Expr) {
+ // If there is one DW_OP_deref element, use offset of 0 and keep going.
+ if (VI.Expr->getNumElements() == 1 &&
+ VI.Expr->getElement(0) == llvm::dwarf::DW_OP_deref)
+ Deref = true;
+ else if (!VI.Expr->extractIfOffset(ExprOffset))
continue;
+ }
// Get the frame register used and the offset.
unsigned FrameReg = 0;
@@ -1154,6 +1160,7 @@ void CodeViewDebug::collectVariableInfoF
// Calculate the label ranges.
LocalVarDefRange DefRange =
createDefRangeMem(CVReg, FrameOffset + ExprOffset);
+
for (const InsnRange &Range : Scope->getRanges()) {
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
@@ -1164,6 +1171,9 @@ void CodeViewDebug::collectVariableInfoF
LocalVariable Var;
Var.DIVar = VI.Var;
Var.DefRanges.emplace_back(std::move(DefRange));
+ if (Deref)
+ Var.UseReferenceType = true;
+
recordLocalVariable(std::move(Var), Scope);
}
}
Added: llvm/trunk/test/DebugInfo/COFF/nrvo.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/COFF/nrvo.ll?rev=363952&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/COFF/nrvo.ll (added)
+++ llvm/trunk/test/DebugInfo/COFF/nrvo.ll Thu Jun 20 10:15:21 2019
@@ -0,0 +1,144 @@
+; RUN: llc < %s | FileCheck %s --check-prefix=ASM
+; RUN: llc < %s -filetype=obj | llvm-readobj - --codeview | FileCheck %s --check-prefix=OBJ
+
+; C++ source to regenerate:
+; struct Foo {
+; Foo() = default;
+; Foo(Foo &&other) { x = other.x; }
+; int x;
+; };
+; void some_function(int);
+; Foo getFoo() {
+; Foo foo;
+; foo.x = 41;
+; some_function(foo.x);
+; return foo;
+; }
+;
+; int main() {
+; Foo bar = getFoo();
+; return bar.x;
+; }
+; $ clang t.cpp -S -emit-llvm -g -o t.ll
+
+; ASM-LABEL: .long 241 # Symbol subsection for GetFoo
+; ASM: .short 4414 # Record kind: S_LOCAL
+; ASM-NEXT: .long 4113 # TypeIndex
+; ASM-NEXT: .short 0 # Flags
+; ASM-NEXT: .asciz "foo"
+; ASM-NEXT: .p2align 2
+; ASM-NEXT: .Ltmp
+; ASM: .cv_def_range .Ltmp{{.*}} .Ltmp{{.*}}, "B\021(\000\000\000"
+
+; OBJ: Subsection [
+; OBJ: SubSectionType: Symbols (0xF1)
+; OBJ: LocalSym {
+; OBJ: Kind: S_LOCAL (0x113E)
+; OBJ: Type: Foo& (0x1011)
+; OBJ: Flags [ (0x0)
+; OBJ: ]
+; OBJ: VarName: foo
+; OBJ: }
+; OBJ: DefRangeFramePointerRelSym {
+; OBJ: Kind: S_DEFRANGE_FRAMEPOINTER_REL (0x1142)
+; OBJ: Offset: 40
+; OBJ: LocalVariableAddrRange {
+; OBJ: OffsetStart: .text+0x1D
+; OBJ: ISectStart: 0x0
+; OBJ: Range: 0x16
+; OBJ: }
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.16.27030"
+
+%struct.Foo = type { i32 }
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @"?some_function@@YAXH at Z"(i32) #0 !dbg !8 {
+entry:
+ %.addr = alloca i32, align 4
+ store i32 %0, i32* %.addr, align 4
+ call void @llvm.dbg.declare(metadata i32* %.addr, metadata !12, metadata !DIExpression()), !dbg !13
+ ret void, !dbg !13
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @"?GetFoo@@YA?AUFoo@@XZ"(%struct.Foo* noalias sret %agg.result) #0 !dbg !14 {
+entry:
+ %result.ptr = alloca i8*, align 8
+ %0 = bitcast %struct.Foo* %agg.result to i8*
+ store i8* %0, i8** %result.ptr, align 8
+ call void @llvm.dbg.declare(metadata i8** %result.ptr, metadata !28, metadata !DIExpression(DW_OP_deref)), !dbg !29
+ %x = getelementptr inbounds %struct.Foo, %struct.Foo* %agg.result, i32 0, i32 0, !dbg !30
+ store i32 41, i32* %x, align 4, !dbg !30
+ %x1 = getelementptr inbounds %struct.Foo, %struct.Foo* %agg.result, i32 0, i32 0, !dbg !31
+ %1 = load i32, i32* %x1, align 4, !dbg !31
+ call void @"?some_function@@YAXH at Z"(i32 %1), !dbg !31
+ ret void, !dbg !32
+}
+
+; Function Attrs: noinline norecurse nounwind optnone uwtable
+define dso_local i32 @main() #2 !dbg !33 {
+entry:
+ %retval = alloca i32, align 4
+ %bar = alloca %struct.Foo, align 4
+ store i32 0, i32* %retval, align 4
+ call void @llvm.dbg.declare(metadata %struct.Foo* %bar, metadata !36, metadata !DIExpression()), !dbg !37
+ call void @"?GetFoo@@YA?AUFoo@@XZ"(%struct.Foo* sret %bar), !dbg !37
+ %x = getelementptr inbounds %struct.Foo, %struct.Foo* %bar, i32 0, i32 0, !dbg !38
+ %0 = load i32, i32* %x, align 4, !dbg !38
+ ret i32 %0, !dbg !38
+}
+
+attributes #0 = { noinline nounwind optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone speculatable }
+attributes #2 = { noinline norecurse nounwind optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project.git c19ebebac4bf853e77a69c74abe9f7fce98c1d17)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "t.cpp", directory: "C:\5Csrc\5Ctesting\5Cnrvo", checksumkind: CSK_MD5, checksum: "52a5a20c02c102dfd255d5615680a8bd")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git c19ebebac4bf853e77a69c74abe9f7fce98c1d17)"}
+!8 = distinct !DISubprogram(name: "some_function", linkageName: "?some_function@@YAXH at Z", scope: !1, file: !1, line: 13, type: !9, scopeLine: 13, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null, !11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocalVariable(arg: 1, scope: !8, file: !1, line: 13, type: !11)
+!13 = !DILocation(line: 13, scope: !8)
+!14 = distinct !DISubprogram(name: "GetFoo", linkageName: "?GetFoo@@YA?AUFoo@@XZ", scope: !1, file: !1, line: 15, type: !15, scopeLine: 15, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!15 = !DISubroutineType(types: !16)
+!16 = !{!17}
+!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !1, line: 1, size: 32, flags: DIFlagTypePassByReference | DIFlagNonTrivial, elements: !18, identifier: ".?AUFoo@@")
+!18 = !{!19, !20, !24}
+!19 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !17, file: !1, line: 4, baseType: !11, size: 32)
+!20 = !DISubprogram(name: "Foo", scope: !17, file: !1, line: 2, type: !21, scopeLine: 2, flags: DIFlagPrototyped, spFlags: 0)
+!21 = !DISubroutineType(types: !22)
+!22 = !{null, !23}
+!23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !17, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
+!24 = !DISubprogram(name: "Foo", scope: !17, file: !1, line: 3, type: !25, scopeLine: 3, flags: DIFlagPrototyped, spFlags: 0)
+!25 = !DISubroutineType(types: !26)
+!26 = !{null, !23, !27}
+!27 = !DIDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: !17, size: 64)
+!28 = !DILocalVariable(name: "foo", scope: !14, file: !1, line: 17, type: !17)
+!29 = !DILocation(line: 17, scope: !14)
+!30 = !DILocation(line: 18, scope: !14)
+!31 = !DILocation(line: 19, scope: !14)
+!32 = !DILocation(line: 21, scope: !14)
+!33 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 23, type: !34, scopeLine: 23, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!34 = !DISubroutineType(types: !35)
+!35 = !{!11}
+!36 = !DILocalVariable(name: "bar", scope: !33, file: !1, line: 24, type: !17)
+!37 = !DILocation(line: 24, scope: !33)
+!38 = !DILocation(line: 25, scope: !33)
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