From 441cfee780c5c9be461012e53ed5a7e1b837fd31 Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Mon, 15 May 2017 21:34:01 +0000 Subject: [PATCH] PR32288: Describe a bool parameter's DWARF location with a simple register There's no need (& a bit incorrect) to mask off the high bits of the register reference when describing a simple bool value. Reviewers: aprantl Differential Revision: https://reviews.llvm.org/D31062 llvm-svn: 303117 --- llvm/lib/Transforms/Utils/Local.cpp | 51 ++++----- llvm/test/Transforms/Util/split-bit-piece.ll | 108 +++++++++++++------ 2 files changed, 98 insertions(+), 61 deletions(-) diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 608834b06deb..1ca509472b5f 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -1105,8 +1105,9 @@ static bool PhiHasDebugValue(DILocalVariable *DIVar, void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI, StoreInst *SI, DIBuilder &Builder) { auto *DIVar = DDI->getVariable(); - auto *DIExpr = DDI->getExpression(); assert(DIVar && "Missing variable"); + auto *DIExpr = DDI->getExpression(); + Value *DV = SI->getOperand(0); // If an argument is zero extended then use argument directly. The ZExt // may be zapped by an optimization pass in future. @@ -1116,34 +1117,28 @@ void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI, if (SExtInst *SExt = dyn_cast(SI->getOperand(0))) ExtendedArg = dyn_cast(SExt->getOperand(0)); if (ExtendedArg) { - // We're now only describing a subset of the variable. The fragment we're - // describing will always be smaller than the variable size, because - // VariableSize == Size of Alloca described by DDI. Since SI stores - // to the alloca described by DDI, if it's first operand is an extend, - // we're guaranteed that before extension, the value was narrower than - // the size of the alloca, hence the size of the described variable. - SmallVector Ops; - unsigned FragmentOffset = 0; - // If this already is a bit fragment, we drop the bit fragment from the - // expression and record the offset. - auto Fragment = DIExpr->getFragmentInfo(); - if (Fragment) { - Ops.append(DIExpr->elements_begin(), DIExpr->elements_end()-3); - FragmentOffset = Fragment->OffsetInBits; - } else { - Ops.append(DIExpr->elements_begin(), DIExpr->elements_end()); + // If this DDI was already describing only a fragment of a variable, ensure + // that fragment is appropriately narrowed here. + // But if a fragment wasn't used, describe the value as the original + // argument (rather than the zext or sext) so that it remains described even + // if the sext/zext is optimized away. This widens the variable description, + // leaving it up to the consumer to know how the smaller value may be + // represented in a larger register. + if (auto Fragment = DIExpr->getFragmentInfo()) { + unsigned FragmentOffset = Fragment->OffsetInBits; + SmallVector Ops(DIExpr->elements_begin(), + DIExpr->elements_end() - 3); + Ops.push_back(dwarf::DW_OP_LLVM_fragment); + Ops.push_back(FragmentOffset); + const DataLayout &DL = DDI->getModule()->getDataLayout(); + Ops.push_back(DL.getTypeSizeInBits(ExtendedArg->getType())); + DIExpr = Builder.createExpression(Ops); } - Ops.push_back(dwarf::DW_OP_LLVM_fragment); - Ops.push_back(FragmentOffset); - const DataLayout &DL = DDI->getModule()->getDataLayout(); - Ops.push_back(DL.getTypeSizeInBits(ExtendedArg->getType())); - auto NewDIExpr = Builder.createExpression(Ops); - if (!LdStHasDebugValue(DIVar, NewDIExpr, SI)) - Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, NewDIExpr, - DDI->getDebugLoc(), SI); - } else if (!LdStHasDebugValue(DIVar, DIExpr, SI)) - Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, DIExpr, - DDI->getDebugLoc(), SI); + DV = ExtendedArg; + } + if (!LdStHasDebugValue(DIVar, DIExpr, SI)) + Builder.insertDbgValueIntrinsic(DV, 0, DIVar, DIExpr, DDI->getDebugLoc(), + SI); } /// Inserts a llvm.dbg.value intrinsic before a load of an alloca'd value diff --git a/llvm/test/Transforms/Util/split-bit-piece.ll b/llvm/test/Transforms/Util/split-bit-piece.ll index 3d7bcac73ca3..5a374e839926 100644 --- a/llvm/test/Transforms/Util/split-bit-piece.ll +++ b/llvm/test/Transforms/Util/split-bit-piece.ll @@ -3,43 +3,85 @@ ; if it only describes part of the variable. ; RUN: opt -S -sroa %s | FileCheck %s -; Function Attrs: nounwind readnone -declare void @llvm.dbg.declare(metadata, metadata, metadata) #0 +; Built from: +; struct foo { bool b; long i; }; +; void f(bool b, bool expr, foo g) { +; } +; And modifying the frag dbg.declare to use a fragmented DIExpression (with offset: 0, size: 4) +; to test the dbg.declare+fragment case here. -; Function Attrs: nounwind uwtable -define hidden void @_ZN6__tsan9FastState14SetHistorySizeEi(i32 %hs) #1 align 2 { +; Expect two fragments: +; * first starting at bit 0, 8 bits (for the bool) +; * second starting at bit 32, 32 bits (for the long) +; (this happens to create/demonstrate a gap from bits [7, 32)) + +; But also check that a complex expression is not used for a lone bool +; parameter. It can reference the register it's in directly without masking off +; high bits or anything + +; CHECK: call void @llvm.dbg.value(metadata i8 %g.coerce0, i64 0, metadata ![[VAR_STRUCT:[0-9]+]], metadata ![[EXPR_STRUCT1:[0-9]+]]) +; CHECK: call void @llvm.dbg.value(metadata i64 %g.coerce1, i64 0, metadata ![[VAR_STRUCT]], metadata ![[EXPR_STRUCT2:[0-9]+]]) +; CHECK: call void @llvm.dbg.value(metadata i1 %b, i64 0, metadata ![[VAR_BOOL:[0-9]+]], metadata ![[EXPR_BOOL:[0-9]+]]) +; CHECK: call void @llvm.dbg.value(metadata i1 %frag, i64 0, metadata ![[FRAG_BOOL:[0-9]+]], metadata ![[FRAG_BOOL:[0-9]+]]) +; CHECK: ![[EXPR_STRUCT1]] = !DIExpression(DW_OP_LLVM_fragment, 0, 8) +; CHECK: ![[EXPR_STRUCT2]] = !DIExpression(DW_OP_LLVM_fragment, 32, 64) +; CHECK: ![[EXPR_BOOL]] = !DIExpression() +; CHECK: ![[FRAG_BOOL]] = !DIExpression(DW_OP_LLVM_fragment, 0, 1) + +%struct.foo = type { i8, i64 } + +; Function Attrs: noinline nounwind uwtable +define void @_Z1fbb3foo(i1 zeroext %b, i1 zeroext %frag, i8 %g.coerce0, i64 %g.coerce1) #0 !dbg !6 { entry: - %hs.addr = alloca i32, align 4 - %v1 = alloca i64, align 8 - %v2 = alloca i64, align 8 - store i32 %hs, i32* %hs.addr, align 4 -; CHECK: call void @llvm.dbg.value(metadata i32 %hs, i64 0, metadata !{{[0-9]+}}, metadata ![[EXPR:[0-9]+]]) -; CHECK: ![[EXPR]] = !DIExpression(DW_OP_LLVM_fragment, 0 - call void @llvm.dbg.declare(metadata i64* %v1, metadata !9, metadata !12), !dbg !13 - %0 = load i32, i32* %hs.addr, align 4 - %conv = sext i32 %0 to i64 - store i64 %conv, i64* %v1, align 8 - %1 = load i64, i64* %v2, align 8 - unreachable + %g = alloca %struct.foo, align 8 + %b.addr = alloca i8, align 1 + %frag.addr = alloca i8, align 1 + %0 = bitcast %struct.foo* %g to { i8, i64 }* + %1 = getelementptr inbounds { i8, i64 }, { i8, i64 }* %0, i32 0, i32 0 + store i8 %g.coerce0, i8* %1, align 8 + %2 = getelementptr inbounds { i8, i64 }, { i8, i64 }* %0, i32 0, i32 1 + store i64 %g.coerce1, i64* %2, align 8 + %frombool = zext i1 %b to i8 + store i8 %frombool, i8* %b.addr, align 1 + call void @llvm.dbg.declare(metadata i8* %b.addr, metadata !15, metadata !16), !dbg !17 + %frombool1 = zext i1 %frag to i8 + store i8 %frombool1, i8* %frag.addr, align 1 + call void @llvm.dbg.declare(metadata i8* %frag.addr, metadata !18, metadata !23), !dbg !19 + call void @llvm.dbg.declare(metadata %struct.foo* %g, metadata !20, metadata !16), !dbg !21 + ret void, !dbg !22 } -attributes #0 = { nounwind readnone } +; Function Attrs: nounwind readnone speculatable +declare void @llvm.dbg.declare(metadata, metadata, metadata) #1 + +attributes #0 = { noinline nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "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"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #1 = { nounwind readnone speculatable } !llvm.dbg.cu = !{!0} -!llvm.module.flags = !{!7} -!llvm.ident = !{!8} +!llvm.module.flags = !{!3, !4} +!llvm.ident = !{!5} -!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 256979) (llvm/trunk 257107)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, retainedTypes: !2) -!1 = !DIFile(filename: "tsan_shadow_test.cc", directory: "/tmp") -!2 = !{!3, !5} -!3 = !DICompositeType(tag: DW_TAG_class_type, name: "FastState", file: !4, line: 91, size: 64, align: 64, identifier: "_ZTSN6__tsan9FastStateE") -!4 = !DIFile(filename: "/mnt/extra/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_rtl.h", directory: "/tmp") -!5 = distinct !DIDerivedType(tag: DW_TAG_typedef, name: "u64", line: 78, baseType: !6) -!6 = !DIBasicType(name: "long long unsigned int", size: 64, align: 64, encoding: DW_ATE_unsigned) -!7 = !{i32 2, !"Debug Info Version", i32 3} -!8 = !{!"clang version 3.8.0 (trunk 256979) (llvm/trunk 257107)"} -!9 = !DILocalVariable(name: "v1", scope: !10, file: !4, line: 136, type: !5) -!10 = distinct !DILexicalBlock(scope: !11, file: !4, line: 136, column: 5) -!11 = distinct !DISubprogram(name: "SetHistorySize", linkageName: "_ZN6__tsan9FastState14SetHistorySizeEi", scope: !3, file: !4, line: 135, isLocal: false, isDefinition: true, scopeLine: 135, flags: DIFlagPrototyped, isOptimized: false, unit: !0) -!12 = !DIExpression() -!13 = !DILocation(line: 136, column: 5, scope: !10) +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 (trunk 303077) (llvm/trunk 303098)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) +!1 = !DIFile(filename: "foo.cpp", directory: "/usr/local/google/home/blaikie/dev/scratch") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{!"clang version 5.0.0 (trunk 303077) (llvm/trunk 303098)"} +!6 = distinct !DISubprogram(name: "f", linkageName: "_Z1fbb3foo", scope: !1, file: !1, line: 2, type: !7, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2) +!7 = !DISubroutineType(types: !8) +!8 = !{null, !9, !9, !10} +!9 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean) +!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo", file: !1, line: 1, size: 128, elements: !11, identifier: "_ZTS3foo") +!11 = !{!12, !13} +!12 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !10, file: !1, line: 1, baseType: !9, size: 8) +!13 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !10, file: !1, line: 1, baseType: !14, size: 64, offset: 64) +!14 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed) +!15 = !DILocalVariable(name: "b", arg: 1, scope: !6, file: !1, line: 2, type: !9) +!16 = !DIExpression() +!17 = !DILocation(line: 2, column: 13, scope: !6) +!18 = !DILocalVariable(name: "frag", arg: 2, scope: !6, file: !1, line: 2, type: !9) +!19 = !DILocation(line: 2, column: 21, scope: !6) +!20 = !DILocalVariable(name: "g", arg: 3, scope: !6, file: !1, line: 2, type: !10) +!21 = !DILocation(line: 2, column: 31, scope: !6) +!22 = !DILocation(line: 3, column: 1, scope: !6) +!23 = !DIExpression(DW_OP_LLVM_fragment, 0, 4)