Object: Improve COFF irsymtab comdat representation.

Change the representation of COFF comdats so that a COFF linker
is able to accurately resolve comdats between IR and native object
files. Specifically, apply name mangling to comdat names consistently
with native object files, and do not export comdats with an internal
leader because they do not affect symbol resolution.

Differential Revision: https://reviews.llvm.org/D40278

llvm-svn: 318805

1 files changed, 21 insertions, 4 deletions

diff --git a/llvm/test/LTO/Resolution/X86/symtab.ll b/llvm/test/LTO/Resolution/X86/symtab.ll
index fecea0a1e7b..c43494a5b7e 100644
--- a/llvm/test/LTO/Resolution/X86/symtab.ll
+++ b/llvm/test/LTO/Resolution/X86/symtab.ll
@@ -17,6 +17,15 @@ define i32 @fun() {
   ret i32 0
 }
 
+; CHECK: D------X @fun2@8
+; CHECK-NEXT: comdat @fun2@8
+$fun2 = comdat any
+define x86_fastcallcc i32 @fun2(i32 inreg %a, i32 inreg %b) comdat {
+entry:
+  %add = add nsw i32 %b, %a
+  ret i32 %add
+}
+
 ; CHECK: H------- _g1
 @g1 = hidden global i32 0
 
@@ -43,11 +52,19 @@ define i32 @fun() {
 @g8 = common global i32 0, align 8
 
 ; CHECK: D------- _g9
-; CHECK-NEXT: comdat g9
+; CHECK-NEXT: comdat _g9
 $g9 = comdat any
 @g9 = global i32 0, comdat
 
-; CHECK: D--WI--- _g10
-; CHECK-NEXT: comdat g9
+; CHECK-NOT: _g10
+$g10 = comdat any
+@g10 = internal global i32 0, comdat
+
+; CHECK: D------- _g11
+; CHECK-NOT: comdat
+@g11 = global i32 0, comdat($g10)
+
+; CHECK: D--WI--- _a1
+; CHECK-NEXT: comdat _g9
 ; CHECK-NEXT: fallback _g9
-@g10 = weak alias i32, i32* @g9
+@a1 = weak alias i32, i32* @g9