[PATCH] D100909: [MC] Use COMDAT for LSDA only if IR comdat type is any

[Petr Hosek via Phabricator via llvm-commits]

phosek updated this revision to Diff 339326.
phosek marked 2 inline comments as done.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100909/new/

https://reviews.llvm.org/D100909

Files:
  llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
  llvm/test/CodeGen/X86/gcc_except_table-multi.ll


Index: llvm/test/CodeGen/X86/gcc_except_table-multi.ll
===================================================================
--- llvm/test/CodeGen/X86/gcc_except_table-multi.ll
+++ llvm/test/CodeGen/X86/gcc_except_table-multi.ll
@@ -53,6 +53,28 @@
   resume { i8*, i32 } %0
 }
 
+;; If the function is in a comdat group with noduplicates kind, the generated
+;; .gcc_except_table should is lowered to a zero-flag ELF section group.
+$zero = comdat noduplicates
+define i32 @zero() uwtable comdat personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-LABEL:       zero:
+; CHECK:             .cfi_endproc
+; NORMAL-NEXT:       .section .gcc_except_table.zero,"aG", at progbits,zero{{$}}
+; SEP_BFD-NEXT:      .section .gcc_except_table.zero,"aG", at progbits,zero{{$}}
+; SEP-NEXT:          .section .gcc_except_table.zero,"aGo", at progbits,zero,zero{{$}}
+; SEP_NOUNIQUE-NEXT: .section .gcc_except_table,"aG", at progbits,zero{{$}}
+; NOUNIQUE-NEXT:     .section .gcc_except_table,"aG", at progbits,zero{{$}}
+entry:
+  invoke void @ext() to label %try.cont unwind label %lpad
+lpad:
+  %0 = landingpad { i8*, i32 } catch i8* bitcast (i8** @_ZTIi to i8*)
+  br label %eh.resume
+try.cont:
+  ret i32 0
+eh.resume:
+  resume { i8*, i32 } %0
+}
+
 declare void @ext()
 
 declare i32 @__gxx_personality_v0(...)
Index: llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
===================================================================
--- llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -890,9 +890,11 @@
   unsigned Flags = LSDA->getFlags();
   const MCSymbolELF *LinkedToSym = nullptr;
   StringRef Group;
+  bool IsComdat = false;
   if (const Comdat *C = getELFComdat(&F)) {
     Flags |= ELF::SHF_GROUP;
     Group = C->getName();
+    IsComdat = C->getSelectionKind() == Comdat::Any;
   }
   // Use SHF_LINK_ORDER to facilitate --gc-sections if we can use GNU ld>=2.36
   // or LLD, which support mixed SHF_LINK_ORDER & non-SHF_LINK_ORDER.
@@ -908,7 +910,7 @@
   return getContext().getELFSection(
       (TM.getUniqueSectionNames() ? LSDA->getName() + "." + F.getName()
                                   : LSDA->getName()),
-      LSDA->getType(), Flags, 0, Group, F.hasComdat(), MCSection::NonUniqueID,
+      LSDA->getType(), Flags, 0, Group, IsComdat, MCSection::NonUniqueID,
       LinkedToSym);
 }
 


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