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llvm-project/llvm/test/Transforms/InstCombine/alloca-cast-debuginfo.ll

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Make salvageDebugInfo of casts work for dbg.declare and dbg.addr Summary: Instcombine (and probably other passes) sometimes want to change the type of an alloca. To do this, they generally create a new alloca with the desired type, create a bitcast to make the new pointer type match the old pointer type, replace all uses with the cast, and then simplify the casts. We already knew how to salvage dbg.value instructions when removing casts, but we can extend it to cover dbg.addr and dbg.declare. Fixes a debug info quality issue uncovered in Chromium in http://crbug.com/784609 Reviewers: aprantl, vsk Subscribers: hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D40042 llvm-svn: 318203
2017-11-15 05:49:06 +08:00
; RUN: opt < %s -S -instcombine -instcombine-lower-dbg-declare=0 | FileCheck %s
; In this example, instcombine wants to turn "local" into an i64, since that's
; how it is stored. It should keep the debug info referring to the alloca when
; it does the replacement.
; C source:
; struct Foo {
; int x, y;
; };
; void escape(const void*);
; void f(struct Foo *p) {
; struct Foo local;
; *(__int64 *)&local = *(__int64 *)p;
; escape(&local);
; }
; ModuleID = '<stdin>'
source_filename = "t.c"
target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc19.11.25508"
%struct.Foo = type { i32, i32 }
define void @f(%struct.Foo* %p) !dbg !11 {
entry:
%local = alloca %struct.Foo, align 4
%0 = bitcast %struct.Foo* %local to i8*, !dbg !24
call void @llvm.dbg.declare(metadata %struct.Foo* %local, metadata !22, metadata !DIExpression()), !dbg !25
%1 = bitcast %struct.Foo* %p to i64*, !dbg !26
%2 = load i64, i64* %1, align 8, !dbg !26, !tbaa !27
%3 = bitcast %struct.Foo* %local to i64*, !dbg !31
store i64 %2, i64* %3, align 4, !dbg !32, !tbaa !27
%4 = bitcast %struct.Foo* %local to i8*, !dbg !33
call void @escape(i8* %4), !dbg !34
%5 = bitcast %struct.Foo* %local to i8*, !dbg !35
ret void, !dbg !35
}
; CHECK-LABEL: define void @f(%struct.Foo* %p)
; CHECK: %local = alloca i64, align 8
; CHECK: call void @llvm.dbg.declare(metadata i64* %local, metadata !22, metadata !DIExpression())
[InstCombine] Preserve debug values for eliminable casts A cast from A to B is eliminable if its result is casted to C, and if the pair of casts could just be expressed as a single cast. E.g here, %c1 is eliminable: %c1 = zext i16 %A to i32 %c2 = sext i32 %c1 to i64 InstCombine optimizes away eliminable casts. This patch teaches it to insert a dbg.value intrinsic pointing to the final result, so that local variables pointing to the eliminable result are preserved. Differential Revision: https://reviews.llvm.org/D42566 llvm-svn: 323570
2018-01-27 06:02:52 +08:00
; CHECK: [[simplified:%.*]] = bitcast i64* %local to i8*
[Local] replaceAllDbgUsesWith: Update debug values before RAUW The replaceAllDbgUsesWith utility helps passes preserve debug info when replacing one value with another. This improves upon the existing insertReplacementDbgValues API by: - Updating debug intrinsics in-place, while preventing use-before-def of the replacement value. - Falling back to salvageDebugInfo when a replacement can't be made. - Moving the responsibiliy for rewriting llvm.dbg.* DIExpressions into common utility code. Along with the API change, this teaches replaceAllDbgUsesWith how to create DIExpressions for three basic integer and pointer conversions: - The no-op conversion. Applies when the values have the same width, or have bit-for-bit compatible pointer representations. - Truncation. Applies when the new value is wider than the old one. - Zero/sign extension. Applies when the new value is narrower than the old one. Testing: - check-llvm, check-clang, a stage2 `-g -O3` build of clang, regression/unit testing. - This resolves a number of mis-sized dbg.value diagnostics from Debugify. Differential Revision: https://reviews.llvm.org/D48676 llvm-svn: 336451
2018-07-07 01:32:39 +08:00
;
; Another dbg.value for "local" would be redundant here.
; CHECK-NOT: call void @llvm.dbg.value(metadata i8* [[simplified]], metadata !22, metadata !DIExpression())
;
[ValueTracking] Look through casts when determining non-nullness Bitcast and certain Ptr2Int/Int2Ptr instructions will not alter the value of their operand and can therefore be looked through when we determine non-nullness. Differential Revision: https://reviews.llvm.org/D54956 llvm-svn: 352293
2019-01-27 07:40:35 +08:00
; CHECK: call void @escape(i8* nonnull [[simplified]])
[InstCombine] Preserve debug values for eliminable casts A cast from A to B is eliminable if its result is casted to C, and if the pair of casts could just be expressed as a single cast. E.g here, %c1 is eliminable: %c1 = zext i16 %A to i32 %c2 = sext i32 %c1 to i64 InstCombine optimizes away eliminable casts. This patch teaches it to insert a dbg.value intrinsic pointing to the final result, so that local variables pointing to the eliminable result are preserved. Differential Revision: https://reviews.llvm.org/D42566 llvm-svn: 323570
2018-01-27 06:02:52 +08:00
; CHECK: ret void
Make salvageDebugInfo of casts work for dbg.declare and dbg.addr Summary: Instcombine (and probably other passes) sometimes want to change the type of an alloca. To do this, they generally create a new alloca with the desired type, create a bitcast to make the new pointer type match the old pointer type, replace all uses with the cast, and then simplify the casts. We already knew how to salvage dbg.value instructions when removing casts, but we can extend it to cover dbg.addr and dbg.declare. Fixes a debug info quality issue uncovered in Chromium in http://crbug.com/784609 Reviewers: aprantl, vsk Subscribers: hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D40042 llvm-svn: 318203
2017-11-15 05:49:06 +08:00
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare void @escape(i8*)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!6, !7, !8, !9}
!llvm.ident = !{!10}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3)
!1 = !DIFile(filename: "t.c", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "d7473625866433067a75fd7d03d2abf7")
!2 = !{}
!3 = !{!4}
!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
!5 = !DIBasicType(name: "long long int", size: 64, encoding: DW_ATE_signed)
!6 = !{i32 2, !"CodeView", i32 1}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{i32 1, !"wchar_size", i32 2}
!9 = !{i32 7, !"PIC Level", i32 2}
!10 = !{!"clang version 6.0.0 "}
[DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label. In order to set breakpoints on labels and list source code around labels, we need collect debug information for labels, i.e., label name, the function label belong, line number in the file, and the address label located. In order to keep these information in LLVM IR and to allow backend to generate debug information correctly. We create a new kind of metadata for labels, DILabel. The format of DILabel is !DILabel(scope: !1, name: "foo", file: !2, line: 3) We hope to keep debug information as much as possible even the code is optimized. So, we create a new kind of intrinsic for label metadata to avoid the metadata is eliminated with basic block. The intrinsic will keep existing if we keep it from optimized out. The format of the intrinsic is llvm.dbg.label(metadata !1) It has only one argument, that is the DILabel metadata. The intrinsic will follow the label immediately. Backend could get the label metadata through the intrinsic's parameter. We also create DIBuilder API for labels to be used by Frontend. Frontend could use createLabel() to allocate DILabel objects, and use insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR. Differential Revision: https://reviews.llvm.org/D45024 Patch by Hsiangkai Wang. llvm-svn: 331841
2018-05-09 10:40:45 +08:00
!11 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 5, type: !12, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !20)
Make salvageDebugInfo of casts work for dbg.declare and dbg.addr Summary: Instcombine (and probably other passes) sometimes want to change the type of an alloca. To do this, they generally create a new alloca with the desired type, create a bitcast to make the new pointer type match the old pointer type, replace all uses with the cast, and then simplify the casts. We already knew how to salvage dbg.value instructions when removing casts, but we can extend it to cover dbg.addr and dbg.declare. Fixes a debug info quality issue uncovered in Chromium in http://crbug.com/784609 Reviewers: aprantl, vsk Subscribers: hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D40042 llvm-svn: 318203
2017-11-15 05:49:06 +08:00
!12 = !DISubroutineType(types: !13)
!13 = !{null, !14}
!14 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !15, size: 64)
!15 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !1, line: 1, size: 64, elements: !16)
!16 = !{!17, !19}
!17 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !15, file: !1, line: 2, baseType: !18, size: 32)
!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!19 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !15, file: !1, line: 2, baseType: !18, size: 32, offset: 32)
!20 = !{!21, !22}
!21 = !DILocalVariable(name: "p", arg: 1, scope: !11, file: !1, line: 5, type: !14)
!22 = !DILocalVariable(name: "local", scope: !11, file: !1, line: 6, type: !15)
!23 = !DILocation(line: 5, column: 20, scope: !11)
!24 = !DILocation(line: 6, column: 3, scope: !11)
!25 = !DILocation(line: 6, column: 14, scope: !11)
!26 = !DILocation(line: 7, column: 24, scope: !11)
!27 = !{!28, !28, i64 0}
!28 = !{!"long long", !29, i64 0}
!29 = !{!"omnipotent char", !30, i64 0}
!30 = !{!"Simple C/C++ TBAA"}
!31 = !DILocation(line: 7, column: 3, scope: !11)
!32 = !DILocation(line: 7, column: 22, scope: !11)
!33 = !DILocation(line: 8, column: 10, scope: !11)
!34 = !DILocation(line: 8, column: 3, scope: !11)
!35 = !DILocation(line: 9, column: 1, scope: !11)