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clang-p2996/llvm/test/Transforms/InstCombine/debuginfo-dce.ll
Florian Hahn ffc498dfcc Align definition of DW_OP_plus with DWARF spec [3/3] 
Summary:
This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things.
 
The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack.
 
This is done in three stages:
• The first patch (LLVM) adds support for DW_OP_plus_uconst.
• The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst.
• The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions.

Patch by Sander de Smalen.

Reviewers: echristo, pcc, aprantl

Reviewed By: aprantl

Subscribers: fhahn, javed.absar, aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D33894

llvm-svn: 305386
2017-06-14 13:14:38 +00:00

147 lines
7.6 KiB
LLVM
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; 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 !22 {
entry:
%im_not_dead = alloca i8*
%0 = bitcast %struct.entry* %queue to i8*, !dbg !23
%1 = bitcast %struct.entry* %queue to i8*, !dbg !23
call void @llvm.dbg.value(metadata i8* %1, i64 0, metadata !24, metadata !20), !dbg !23
; 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 !23
}
define void @salvage_gep0(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !25 {
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !26
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !26
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !27, metadata !20), !dbg !26
; CHECK: define void @salvage_gep0
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @llvm.dbg.value(metadata %struct.entry* %queue, i64 0,
; CHECK-SAME: metadata ![[GEP0_EXPR:[0-9]+]])
store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
ret void, !dbg !26
}
define void @salvage_gep1(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !28 {
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !29
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !29
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !30, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 32)), !dbg !29
; 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 !29
}
define void @salvage_gep2(%struct.entry* %queue, %struct.entry* %end) local_unnamed_addr #0 !dbg !31 {
entry:
%im_not_dead = alloca %struct.entry**
%0 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !32
%1 = getelementptr inbounds %struct.entry, %struct.entry* %queue, i32 -1, i32 0, !dbg !32
call void @llvm.dbg.value(metadata %struct.entry** %1, i64 0, metadata !33, metadata !DIExpression(DW_OP_stack_value)), !dbg !32
; 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]+]])
store %struct.entry** %1, %struct.entry*** %im_not_dead, align 8
ret void, !dbg !32
}
; CHECK: ![[LOAD_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_plus_uconst, 0)
; CHECK: ![[BITCAST_EXPR]] = !DIExpression(DW_OP_plus_uconst, 0)
; CHECK: ![[GEP0_EXPR]] = !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 0, DW_OP_stack_value)
; CHECK: ![[GEP1_EXPR]] = !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_stack_value,
; CHECK-SAME: DW_OP_LLVM_fragment, 0, 32)
; CHECK: ![[GEP2_EXPR]] = !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_stack_value)
; 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_uconst, 0)
!21 = !DILocation(line: 11, column: 1, scope: !14)
!22 = 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)
!23 = !DILocation(line: 6, column: 17, scope: !22)
!24 = !DILocalVariable(name: "entry", scope: !22, file: !1, line: 6, type: !4)
!25 = 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)
!26 = !DILocation(line: 6, column: 17, scope: !25)
!27 = !DILocalVariable(name: "entry", scope: !25, file: !1, line: 6, type: !4)
!28 = 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)
!29 = !DILocation(line: 6, column: 17, scope: !28)
!30 = !DILocalVariable(name: "entry", scope: !28, file: !1, line: 6, type: !4)
!31 = 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)
!32 = !DILocation(line: 6, column: 17, scope: !31)
!33 = !DILocalVariable(name: "entry", scope: !31, file: !1, line: 6, type: !4)
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