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llvm-mirror/test/DebugInfo/X86/sroasplit-5.ll
Adrian Prantl 57907269da [DIExpression] Introduce a dedicated DW_OP_LLVM_fragment operation
so we can stop using DW_OP_bit_piece with the wrong semantics.

The entire back story can be found here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161114/405934.html

The gist is that in LLVM we've been misinterpreting DW_OP_bit_piece's
offset field to mean the offset into the source variable rather than
the offset into the location at the top the DWARF expression stack. In
order to be able to fix this in a subsequent patch, this patch
introduces a dedicated DW_OP_LLVM_fragment operation with the
semantics that we used to apply to DW_OP_bit_piece, which is what we
actually need while inside of LLVM. This patch is complete with a
bitcode upgrade for expressions using the old format. It does not yet
fix the DWARF backend to use DW_OP_bit_piece correctly.

Implementation note: We discussed several options for implementing
this, including reserving a dedicated field in DIExpression for the
fragment size and offset, but using an custom operator at the end of
the expression works just fine and is more efficient because we then
only pay for it when we need it.

Differential Revision: https://reviews.llvm.org/D27361
rdar://problem/29335809

llvm-svn: 288683
2016-12-05 18:04:47 +00:00

91 lines
3.8 KiB
LLVM

; RUN: opt %s -sroa -verify -S -o - | FileCheck %s
; From:
; struct prog_src_register {
; unsigned : 4;
; int Index : 12 + 1;
; unsigned : 12;
; unsigned : 4;
; int : 12 + 1
; } src_reg_for_float() {
; struct prog_src_register a;
; memset(&a, 0, sizeof(a));
; int local = a.Index;
; return a;
; }
; ModuleID = 'pr22495.c'
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; When SROA is creating new smaller allocas, it may add padding.
;
; There should be no debug info for the padding.
; CHECK-NOT: DW_OP_LLVM_fragment, 56
; CHECK: DIExpression(DW_OP_LLVM_fragment, 32, 24)
; CHECK-NOT: DW_OP_LLVM_fragment, 56
; CHECK: DIExpression(DW_OP_LLVM_fragment, 0, 32)
; CHECK-NOT: DW_OP_LLVM_fragment, 56
%struct.prog_src_register = type { i32, i24 }
; Function Attrs: nounwind
define i64 @src_reg_for_float() #0 !dbg !4 {
entry:
%retval = alloca %struct.prog_src_register, align 4
%a = alloca %struct.prog_src_register, align 4
%local = alloca i32, align 4
call void @llvm.dbg.declare(metadata %struct.prog_src_register* %a, metadata !16, metadata !17), !dbg !18
%0 = bitcast %struct.prog_src_register* %a to i8*, !dbg !19
call void @llvm.memset.p0i8.i64(i8* %0, i8 0, i64 8, i32 4, i1 false), !dbg !19
call void @llvm.dbg.declare(metadata i32* %local, metadata !20, metadata !17), !dbg !21
%1 = bitcast %struct.prog_src_register* %a to i32*, !dbg !21
%bf.load = load i32, i32* %1, align 4, !dbg !21
%bf.shl = shl i32 %bf.load, 15, !dbg !21
%bf.ashr = ashr i32 %bf.shl, 19, !dbg !21
store i32 %bf.ashr, i32* %local, align 4, !dbg !21
%2 = bitcast %struct.prog_src_register* %retval to i8*, !dbg !22
%3 = bitcast %struct.prog_src_register* %a to i8*, !dbg !22
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %2, i8* %3, i64 8, i32 4, i1 false), !dbg !22
%4 = bitcast %struct.prog_src_register* %retval to i64*, !dbg !22
%5 = load i64, i64* %4, align 1, !dbg !22
ret i64 %5, !dbg !22
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
; Function Attrs: nounwind
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) #2
; Function Attrs: nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #2
attributes #0 = { nounwind }
attributes #1 = { nounwind readnone }
attributes #2 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!13, !14}
!llvm.ident = !{!15}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.7.0 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "<stdin>", directory: "")
!2 = !{}
!4 = distinct !DISubprogram(name: "src_reg_for_float", line: 7, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, scopeLine: 7, file: !5, scope: !6, type: !7, variables: !2)
!5 = !DIFile(filename: "pr22495.c", directory: "")
!6 = !DIFile(filename: "pr22495.c", directory: "")
!7 = !DISubroutineType(types: !8)
!8 = !{!9}
!9 = !DICompositeType(tag: DW_TAG_structure_type, name: "prog_src_register", line: 1, size: 64, align: 32, file: !5, elements: !10)
!10 = !{!11}
!11 = !DIDerivedType(tag: DW_TAG_member, name: "Index", line: 3, size: 13, align: 32, offset: 4, file: !5, scope: !9, baseType: !12)
!12 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!13 = !{i32 2, !"Dwarf Version", i32 4}
!14 = !{i32 2, !"Debug Info Version", i32 3}
!15 = !{!"clang version 3.7.0 "}
!16 = !DILocalVariable(name: "a", line: 8, scope: !4, file: !6, type: !9)
!17 = !DIExpression()
!18 = !DILocation(line: 8, scope: !4)
!19 = !DILocation(line: 9, scope: !4)
!20 = !DILocalVariable(name: "local", line: 10, scope: !4, file: !6, type: !12)
!21 = !DILocation(line: 10, scope: !4)
!22 = !DILocation(line: 11, scope: !4)