maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/Transforms/InstCombine/debuginfo-dce.ll

135 lines
6.2 KiB
LLVM
Raw Normal View History

Salvage debug info from instructions about to be deleted [Reapplies r297971 and punting on finding a better API for findDbgValues()] This patch improves debug info quality in InstCombine by looking at values that are about to be deleted, checking whether there are any dbg.value instrinsics referring to them, and potentially encoding the semantics of the deleted instruction into the dbg.value's DIExpression. In the example in the testcase (which was extracted from XNU) there is a sequence of %4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41 %5 = bitcast %struct.entry* %4 to i8*, !dbg !42 %add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43 %6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44 call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34 When these instructions are eliminated by instcombine one after another, we can still salvage the otherwise dead debug info: - Bitcasts have no effect, so have the dbg.value point to operand(0) - Loads can be expressed via a DW_OP_deref - Constant gep instructions can be replaced by DWARF expression arithmetic The API introduced by this patch is not specific to instcombine and can be useful in other places, too. rdar://problem/30725338 Differential Revision: https://reviews.llvm.org/D30919 llvm-svn: 297994
2017-03-17 05:14:09 +08:00
; RUN: opt -instcombine %s -S -o - | FileCheck %s
; Verify that the eliminated instructions (bitcast, gep, load) are salvaged into
; a DIExpression.
;
; Originally created from the following C source and then heavily isolated/reduced.
;
; struct entry {
; struct entry *next;
; };
; void scan(struct entry *queue, struct entry *end)
; {
; struct entry *entry;
; for (entry = (struct entry *)((char *)(queue->next) - 8);
; &entry->next == end;
; entry = (struct entry *)((char *)(entry->next) - 8)) {
; }
; }
; ModuleID = '<stdin>'
source_filename = "test.c"
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.12.0"
%struct.entry = type { %struct.entry* }
define void @salvage_load(%struct.entry** %queue) local_unnamed_addr #0 !dbg !14 {
entry:
%im_not_dead = alloca %struct.entry*
%0 = load %struct.entry*, %struct.entry** %queue, align 8, !dbg !19
%1 = load %struct.entry*, %struct.entry** %queue, align 8, !dbg !19
call void @llvm.dbg.value(metadata %struct.entry* %1, i64 0, metadata !18, metadata !20), !dbg !19
; CHECK: define void @salvage_load
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry** %queue, i64 0,
; CHECK-SAME: metadata ![[LOAD_EXPR:[0-9]+]])
store %struct.entry* %1, %struct.entry** %im_not_dead, align 8
ret void, !dbg !21
}
define void @salvage_bitcast(%struct.entry* %queue) local_unnamed_addr #0 !dbg !14 {
entry:
%im_not_dead = alloca i8*
%0 = bitcast %struct.entry* %queue to i8*, !dbg !19
%1 = bitcast %struct.entry* %queue to i8*, !dbg !19
call void @llvm.dbg.value(metadata i8* %1, i64 0, metadata !18, metadata !20), !dbg !19
; CHECK: define void @salvage_bitcast
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
; CHECK-SAME: metadata ![[BITCAST_EXPR:[0-9]+]])
store i8* %1, i8** %im_not_dead, align 8
ret void, !dbg !21
}
Use DW_OP_stack_value when reconstructing variable values with arithmetic. When the location description of a source variable involves arithmetic on the value itself, it needs to be marked with DW_OP_stack_value since it is not describing the variable's location, but rather its value. This is a follow-up to r297971 and fixes the source testcase quoted in the comment in debuginfo-dce.ll. rdar://problem/30725338 This reapplies r301093 without modifications. llvm-svn: 301210
2017-04-25 02:11:42 +08:00
define void @salvage_gep0(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !14 {
Salvage debug info from instructions about to be deleted [Reapplies r297971 and punting on finding a better API for findDbgValues()] This patch improves debug info quality in InstCombine by looking at values that are about to be deleted, checking whether there are any dbg.value instrinsics referring to them, and potentially encoding the semantics of the deleted instruction into the dbg.value's DIExpression. In the example in the testcase (which was extracted from XNU) there is a sequence of %4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41 %5 = bitcast %struct.entry* %4 to i8*, !dbg !42 %add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43 %6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44 call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34 When these instructions are eliminated by instcombine one after another, we can still salvage the otherwise dead debug info: - Bitcasts have no effect, so have the dbg.value point to operand(0) - Loads can be expressed via a DW_OP_deref - Constant gep instructions can be replaced by DWARF expression arithmetic The API introduced by this patch is not specific to instcombine and can be useful in other places, too. rdar://problem/30725338 Differential Revision: https://reviews.llvm.org/D30919 llvm-svn: 297994
2017-03-17 05:14:09 +08:00
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !18, metadata !20), !dbg !19
Use DW_OP_stack_value when reconstructing variable values with arithmetic. When the location description of a source variable involves arithmetic on the value itself, it needs to be marked with DW_OP_stack_value since it is not describing the variable's location, but rather its value. This is a follow-up to r297971 and fixes the source testcase quoted in the comment in debuginfo-dce.ll. rdar://problem/30725338 This reapplies r301093 without modifications. llvm-svn: 301210
2017-04-25 02:11:42 +08:00
; CHECK: define void @salvage_gep0
Salvage debug info from instructions about to be deleted [Reapplies r297971 and punting on finding a better API for findDbgValues()] This patch improves debug info quality in InstCombine by looking at values that are about to be deleted, checking whether there are any dbg.value instrinsics referring to them, and potentially encoding the semantics of the deleted instruction into the dbg.value's DIExpression. In the example in the testcase (which was extracted from XNU) there is a sequence of %4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41 %5 = bitcast %struct.entry* %4 to i8*, !dbg !42 %add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43 %6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44 call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34 When these instructions are eliminated by instcombine one after another, we can still salvage the otherwise dead debug info: - Bitcasts have no effect, so have the dbg.value point to operand(0) - Loads can be expressed via a DW_OP_deref - Constant gep instructions can be replaced by DWARF expression arithmetic The API introduced by this patch is not specific to instcombine and can be useful in other places, too. rdar://problem/30725338 Differential Revision: https://reviews.llvm.org/D30919 llvm-svn: 297994
2017-03-17 05:14:09 +08:00
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
Use DW_OP_stack_value when reconstructing variable values with arithmetic. When the location description of a source variable involves arithmetic on the value itself, it needs to be marked with DW_OP_stack_value since it is not describing the variable's location, but rather its value. This is a follow-up to r297971 and fixes the source testcase quoted in the comment in debuginfo-dce.ll. rdar://problem/30725338 This reapplies r301093 without modifications. llvm-svn: 301210
2017-04-25 02:11:42 +08:00
; CHECK-SAME: metadata ![[GEP0_EXPR:[0-9]+]])
store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
ret void, !dbg !21
}
define void @salvage_gep1(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !14 {
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !18, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 32)), !dbg !19
; CHECK: define void @salvage_gep1
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
; CHECK-SAME: metadata ![[GEP1_EXPR:[0-9]+]])
store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
ret void, !dbg !21
}
define void @salvage_gep2(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !14 {
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !19
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !18, metadata !DIExpression(DW_OP_stack_value)), !dbg !19
; CHECK: define void @salvage_gep2
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
; CHECK-SAME: metadata ![[GEP2_EXPR:[0-9]+]])
Salvage debug info from instructions about to be deleted [Reapplies r297971 and punting on finding a better API for findDbgValues()] This patch improves debug info quality in InstCombine by looking at values that are about to be deleted, checking whether there are any dbg.value instrinsics referring to them, and potentially encoding the semantics of the deleted instruction into the dbg.value's DIExpression. In the example in the testcase (which was extracted from XNU) there is a sequence of %4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41 %5 = bitcast %struct.entry* %4 to i8*, !dbg !42 %add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43 %6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44 call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34 When these instructions are eliminated by instcombine one after another, we can still salvage the otherwise dead debug info: - Bitcasts have no effect, so have the dbg.value point to operand(0) - Loads can be expressed via a DW_OP_deref - Constant gep instructions can be replaced by DWARF expression arithmetic The API introduced by this patch is not specific to instcombine and can be useful in other places, too. rdar://problem/30725338 Differential Revision: https://reviews.llvm.org/D30919 llvm-svn: 297994
2017-03-17 05:14:09 +08:00
store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
ret void, !dbg !21
}
; CHECK: ![[LOAD_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_plus, 0)
; CHECK: ![[BITCAST_EXPR]] = !DIExpression(DW_OP_plus, 0)
Use DW_OP_stack_value when reconstructing variable values with arithmetic. When the location description of a source variable involves arithmetic on the value itself, it needs to be marked with DW_OP_stack_value since it is not describing the variable's location, but rather its value. This is a follow-up to r297971 and fixes the source testcase quoted in the comment in debuginfo-dce.ll. rdar://problem/30725338 This reapplies r301093 without modifications. llvm-svn: 301210
2017-04-25 02:11:42 +08:00
; CHECK: ![[GEP0_EXPR]] = !DIExpression(DW_OP_minus, 8, DW_OP_plus, 0, DW_OP_stack_value)
; CHECK: ![[GEP1_EXPR]] = !DIExpression(DW_OP_minus, 8, DW_OP_stack_value,
; CHECK-SAME: DW_OP_LLVM_fragment, 0, 32)
; CHECK: ![[GEP2_EXPR]] = !DIExpression(DW_OP_minus, 8, DW_OP_stack_value)
Salvage debug info from instructions about to be deleted [Reapplies r297971 and punting on finding a better API for findDbgValues()] This patch improves debug info quality in InstCombine by looking at values that are about to be deleted, checking whether there are any dbg.value instrinsics referring to them, and potentially encoding the semantics of the deleted instruction into the dbg.value's DIExpression. In the example in the testcase (which was extracted from XNU) there is a sequence of %4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41 %5 = bitcast %struct.entry* %4 to i8*, !dbg !42 %add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43 %6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44 call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34 When these instructions are eliminated by instcombine one after another, we can still salvage the otherwise dead debug info: - Bitcasts have no effect, so have the dbg.value point to operand(0) - Loads can be expressed via a DW_OP_deref - Constant gep instructions can be replaced by DWARF expression arithmetic The API introduced by this patch is not specific to instcombine and can be useful in other places, too. rdar://problem/30725338 Differential Revision: https://reviews.llvm.org/D30919 llvm-svn: 297994
2017-03-17 05:14:09 +08:00
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
attributes #0 = { nounwind ssp uwtable }
attributes #1 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!10, !11, !12}
!llvm.ident = !{!13}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 5.0.0 (trunk 297628) (llvm/trunk 297643)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3)
!1 = !DIFile(filename: "test.c", directory: "/")
!2 = !{}
!3 = !{!4, !8}
!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 64)
!5 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "entry", file: !1, line: 1, size: 64, elements: !6)
!6 = !{!7}
!7 = !DIDerivedType(tag: DW_TAG_member, name: "next", scope: !5, file: !1, line: 2, baseType: !4, size: 64)
!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64)
!9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
!10 = !{i32 2, !"Dwarf Version", i32 4}
!11 = !{i32 2, !"Debug Info Version", i32 3}
!12 = !{i32 1, !"PIC Level", i32 2}
!13 = !{!"clang version 5.0.0 (trunk 297628) (llvm/trunk 297643)"}
!14 = distinct !DISubprogram(name: "scan", scope: !1, file: !1, line: 4, type: !15, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !17)
!15 = !DISubroutineType(types: !16)
!16 = !{null, !4, !4}
!17 = !{!18}
!18 = !DILocalVariable(name: "entry", scope: !14, file: !1, line: 6, type: !4)
!19 = !DILocation(line: 6, column: 17, scope: !14)
!20 = !DIExpression(DW_OP_plus, 0)
!21 = !DILocation(line: 11, column: 1, scope: !14)