COFF: Skip internal symbols in bitcode files.

[ruiu]

Is this just for better performance?

[pcc]

No, this is for correctness. Without this change, we will fail to link two modules containing an internal symbol with the same name.

[ruiu]

LGTM

COFF/InputFiles.cpp

M.reset(LTOModule::createFromBuffer(MB.getBufferStart(),
                                       MB.getBufferSize(),
                                       llvm::TargetOptions(), Err));
   if (!Err.empty()) {
     llvm::errs() << Err << '\n';
     return make_error_code(LLDError::BrokenFile);
   }
 
   for (unsigned I = 0, E = M->getSymbolCount(); I != E; ++I) {
+    lto_symbol_attributes Attrs = M->getSymbolAttributes(I);
+    if ((Attrs & LTO_SYMBOL_SCOPE_MASK) == LTO_SYMBOL_SCOPE_INTERNAL)
+      continue;
+
     StringRef SymName = M->getSymbolName(I);
-    if ((M->getSymbolAttributes(I) & LTO_SYMBOL_DEFINITION_MASK) ==
-        LTO_SYMBOL_DEFINITION_UNDEFINED) {
+    int SymbolDef = Attrs & LTO_SYMBOL_DEFINITION_MASK;
+    if (SymbolDef == LTO_SYMBOL_DEFINITION_UNDEFINED) {
       SymbolBodies.push_back(new (Alloc) Undefined(SymName));
     } else {
       SymbolBodies.push_back(new (Alloc) DefinedBitcode(SymName));
     }
   }
 
   // Extract any linker directives from the bitcode file, which are represented
   // as module flags with the key "Linker Options".

test/COFF/Inputs/lto-dep.ll

 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
 define void @foo() {
   ret void
 }
+
+define internal void @internal() {
+  ret void
+}

test/COFF/lto.ll

 ; TEXT-11-NEXT: int3
 ; TEXT-11-NEXT: movl  $2, %eax
 ; TEXT-11-NEXT: retq
 
 ; HEADERS-01: AddressOfEntryPoint: 0x2000
 ; TEXT-01: Disassembly of section .text:
 ; TEXT-01-NEXT: .text:
 ; TEXT-01-NEXT: subq  $40, %rsp
-; TEXT-01-NEXT: callq 7
+; TEXT-01-NEXT: callq 23
 ; TEXT-01-NEXT: xorl  %eax, %eax
 ; TEXT-01-NEXT: addq  $40, %rsp
 ; TEXT-01-NEXT: retq
 ; TEXT-01-NEXT: retq
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: int3
+; TEXT-01-NEXT: retq
 
-; HEADERS-10: AddressOfEntryPoint: 0x2010
+; HEADERS-10: AddressOfEntryPoint: 0x2020
 ; TEXT-10: Disassembly of section .text:
 ; TEXT-10-NEXT: .text:
 ; TEXT-10-NEXT: retq
+; TEXT-10-NEXT: nopw    %cs:(%rax,%rax)
+; TEXT-10-NEXT: retq
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: int3
 ; TEXT-10-NEXT: subq  $40, %rsp
-; TEXT-10-NEXT: callq -25
+; TEXT-10-NEXT: callq -41
 ; TEXT-10-NEXT: xorl  %eax, %eax
 ; TEXT-10-NEXT: addq  $40, %rsp
 ; TEXT-10-NEXT: retq
 
 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
 define i32 @main() {
   call void @foo()
   ret i32 0
 }
 
 declare void @foo()
 
 $f1 = comdat any
 define i32 @f1() comdat($f1) {
   ret i32 1
 }
 
 $f2 = comdat any
 define i32 @f2() comdat($f2) {
   ret i32 2
 }
+
+define internal void @internal() {
+  ret void
+}