maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[DWARF] Line 0 should not have a discriminator. 

It's meaningless and takes up extra space in the line table.

Differential Revision: https://reviews.llvm.org/D37364

llvm-svn: 312751
This commit is contained in:
Paul Robinson 2017-09-07 22:15:44 +00:00
parent 6aa34aadd1
commit bb92137080
2 changed files with 41 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@ -1362,8 +1362,8 @@ void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
if (auto *Scope = cast_or_null<DIScope>(S)) {
Fn = Scope->getFilename();
Dir = Scope->getDirectory();
if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
if (getDwarfVersion() >= 4)
if (Line != 0 && getDwarfVersion() >= 4)
if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
Discriminator = LBF->getDiscriminator();
unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();

39
llvm/test/CodeGen/X86/dbg-line-0-no-discriminator.ll Normal file
View File

@ -0,0 +1,39 @@
; RUN: llc -filetype=obj -use-unknown-locations=Enable -mtriple=x86_64-unknown-linux %s -o %t
; RUN: llvm-dwarfdump -debug-dump=line %t | FileCheck %s
define void @_Z3bazv() !dbg !6 {
call void @_Z3foov(), !dbg !9
call void @_Z3foov() ; no !dbg, so will be marked as line 0
ret void, !dbg !11
}
declare void @_Z3foov()
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}
!llvm.ident = !{!5}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 267219)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "test.cc", directory: ".")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = !{!"clang version 3.9.0 (trunk 267219)"}
!6 = distinct !DISubprogram(name: "baz", linkageName: "_Z3bazv", scope: !1, file: !1, line: 3, type: !7, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!7 = !DISubroutineType(types: !8)
!8 = !{null}
!9 = !DILocation(line: 4, column: 3, scope: !10)
!10 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 1)
!11 = !DILocation(line: 6, column: 1, scope: !6)
; Look at the lengths. We can't verify the line-number-program size
; directly, but the difference in the two lengths should not change
; unexpectedly.
; CHECK: total_length: 0x00000043
; CHECK: prologue_length: 0x0000001e
;
; Verify that we see a line entry with a discriminator, and the next entry
; has line 0 and no discriminator.
; line column file ISA discriminator
; CHECK: 4 3 1 0 1
; CHECK-NEXT: 0 3 1 0 0