[lto] Avoid duplicate symbol error for appending linkage.

[silvas]

Summary

I'm not sure if this is the right solution, since it seems like we need
to do something more with @llvm.global_ctors in
SymbolTable.cpp:addBitcodeFile.

Any ideas?

[• rafael]

I think the check you want is

Symflags & object::BasicSymbolRef::SF_FormatSpecific

Cheers,
Rafael

[silvas]

Update for Rafael's suggestion.

[ruiu]

ELF/InputFiles.cpp

449

We have "using namespace llvm::object" at beginning of this file.

[silvas]

Update for Rui's comment.

[silvas]

Also fixed the if above in r262983.

ELF/InputFiles.cpp

449

Fixed the if above in r262983.

[• rafael]

Lgtm

ELF/InputFiles.cpp

for (const BasicSymbolRef &Sym : Obj->symbols()) {
     const GlobalValue *GV = Obj->getSymbolGV(Sym.getRawDataRefImpl());
     assert(GV);
     uint32_t Flags = Sym.getFlags();
     if (const Comdat *C = GV->getComdat())
       if (!KeptComdats.count(C))
         continue;
     if (!(Flags & object::BasicSymbolRef::SF_Global))
         continue;
+    if (Flags & object::BasicSymbolRef::SF_FormatSpecific)
+      continue;
     uint8_t Visibility = getGvVisibility(GV);
 
     SmallString<64> Name;
     raw_svector_ostream OS(Name);
     Sym.printName(OS);
     StringRef NameRef = Saver.save(StringRef(Name));
 
     SymbolBody *Body;

test/ELF/lto/linkage.ll

 ; REQUIRES: x86
 ; RUN: llvm-as %s -o %t1.o
 ; RUN: ld.lld -m elf_x86_64 %t1.o %t1.o -o %t.so -shared
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; Should not encounter a duplicate symbol error for @.str
 @.str = private unnamed_addr constant [4 x i8] c"Hey\00", align 1
+
+; Should not encounter a duplicate symbol error for @llvm.global_ctors
[e-mail]_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @ctor, i8* null }]
+define internal void @ctor() {
+  ret void
+}