Add comments from Eric's review of r204094.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204358 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Blaikie 2014-03-20 17:05:45 +00:00
parent 31bd14fc2d
commit b5a1fccdc5
2 changed files with 14 additions and 0 deletions

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@ -688,6 +688,11 @@ DwarfCompileUnit *DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
DwarfCompileUnit *NewCU = new DwarfCompileUnit(
InfoHolder.getUnits().size(), Die, DIUnit, Asm, this, &InfoHolder);
InfoHolder.addUnit(NewCU);
// LTO with assembly output shares a single line table amongst multiple CUs.
// To avoid the compilation directory being ambiguous, let the line table
// explicitly describe the directory of all files, never relying on the
// compilation directory.
if (!Asm->OutStreamer.hasRawTextSupport() || SingleCU)
Asm->OutStreamer.getContext().setMCLineTableCompilationDir(
NewCU->getUniqueID(), CompilationDir);

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@ -3,6 +3,10 @@
; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump -debug-dump=line - | FileCheck %s
; RUN: %llc_dwarf < %s -filetype=asm | FileCheck --check-prefix=ASM %s
; If multiple line tables are emitted, one per CU, those line tables can
; unambiguously rely on the comp_dir of their owning CU and use directory '0'
; to refer to it.
; CHECK: .debug_line contents:
; CHECK-NEXT: Line table prologue:
; CHECK-NOT: include_directories
@ -14,6 +18,11 @@
; CHECK: file_names[ 1] 0 {{.*}} b.cpp
; CHECK-NOT: file_names
; However, if a single line table is emitted and shared between CUs, the
; comp_dir is ambiguous and relying on it would lead to different path
; interpretations depending on which CU lead to the table - so ensure that
; full paths are always emitted in this case, never comp_dir relative.
; ASM: .file 1 "/tmp/dbginfo/a{{[/\\]+}}a.cpp"
; ASM: .file 2 "/tmp/dbginfo/b{{[/\\]+}}b.cpp"