llvm/test/Transforms/InstCombine/lifetime.ll
Adrian Prantl 4eeaa0da04 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266446 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-15 15:57:41 +00:00

93 lines
3.9 KiB
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare void @llvm.lifetime.start(i64, i8* nocapture)
declare void @llvm.lifetime.end(i64, i8* nocapture)
declare void @foo(i8* nocapture, i8* nocapture)
define void @bar(i1 %flag) !dbg !4 {
entry:
; CHECK-LABEL: @bar(
; CHECK: %[[T:[^ ]+]] = getelementptr inbounds [1 x i8], [1 x i8]* %text
; CHECK: %[[B:[^ ]+]] = getelementptr inbounds [1 x i8], [1 x i8]* %buff
; CHECK: if:
; CHECK-NEXT: br label %bb2
; CHECK: bb2:
; CHECK-NEXT: br label %bb3
; CHECK: bb3:
; CHECK-NEXT: call void @llvm.dbg.declare
; CHECK-NEXT: br label %fin
; CHECK: call void @llvm.lifetime.start(i64 1, i8* %[[T]])
; CHECK-NEXT: call void @llvm.lifetime.start(i64 1, i8* %[[B]])
; CHECK-NEXT: call void @foo(i8* %[[B]], i8* %[[T]])
; CHECK-NEXT: call void @llvm.lifetime.end(i64 1, i8* %[[B]])
; CHECK-NEXT: call void @llvm.lifetime.end(i64 1, i8* %[[T]])
%text = alloca [1 x i8], align 1
%buff = alloca [1 x i8], align 1
%0 = getelementptr inbounds [1 x i8], [1 x i8]* %text, i64 0, i64 0
%1 = getelementptr inbounds [1 x i8], [1 x i8]* %buff, i64 0, i64 0
br i1 %flag, label %if, label %else
if:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %bb2
bb2:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
call void @llvm.lifetime.end(i64 1, i8* %1)
br label %bb3
bb3:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.dbg.declare(metadata [1 x i8]* %text, metadata !14, metadata !25), !dbg !26
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %fin
else:
call void @llvm.lifetime.start(i64 1, i8* %0)
call void @llvm.lifetime.start(i64 1, i8* %1)
call void @foo(i8* %1, i8* %0)
call void @llvm.lifetime.end(i64 1, i8* %1)
call void @llvm.lifetime.end(i64 1, i8* %0)
br label %fin
fin:
ret void
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!22, !23}
!llvm.ident = !{!24}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 248826) (llvm/trunk 248827)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "test.cpp", directory: "/home/user")
!2 = !{}
!4 = distinct !DISubprogram(name: "bar", linkageName: "bar", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !8)
!5 = !DISubroutineType(types: !6)
!6 = !{null, !7}
!7 = !DIBasicType(name: "bool", size: 8, align: 8, encoding: DW_ATE_boolean)
!8 = !{!9, !11, !12, !14, !21}
!9 = !DILocalVariable(name: "Size", arg: 1, scope: !4, file: !1, line: 2, type: !10)
!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!11 = !DILocalVariable(name: "flag", arg: 2, scope: !4, file: !1, line: 2, type: !7)
!12 = !DILocalVariable(name: "i", scope: !13, file: !1, line: 3, type: !10)
!13 = distinct !DILexicalBlock(scope: !4, file: !1, line: 3, column: 3)
!14 = !DILocalVariable(name: "text", scope: !15, file: !1, line: 4, type: !17)
!15 = distinct !DILexicalBlock(scope: !16, file: !1, line: 3, column: 30)
!16 = distinct !DILexicalBlock(scope: !13, file: !1, line: 3, column: 3)
!17 = !DICompositeType(tag: DW_TAG_array_type, baseType: !18, size: 8, align: 8, elements: !19)
!18 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
!19 = !{!20}
!20 = !DISubrange(count: 1)
!21 = !DILocalVariable(name: "buff", scope: !15, file: !1, line: 5, type: !17)
!22 = !{i32 2, !"Dwarf Version", i32 4}
!23 = !{i32 2, !"Debug Info Version", i32 3}
!24 = !{!"clang version 3.8.0 (trunk 248826) (llvm/trunk 248827)"}
!25 = !DIExpression()
!26 = !DILocation(line: 4, column: 10, scope: !15)