allow-multiple-definitions should completely suppress errors instead …

…of making them warnings.

We found that when you pass --allow-multiple-definitions or `-z muldefs`
to GNU linkers, they don't complain about duplicate symbols at all. They
don't even print out warnings on it. We emit warnings in that case.
If you pass --fatal-warnings, that difference results in a link failure.

Differential Revision: https://reviews.llvm.org/D44549

llvm-svn: 327920

lld/ELF/SymbolTable.cpp

@@ -410,20 +410,17 @@ Symbol *SymbolTable::addCommon(StringRef N, uint64_t Size, uint32_t Alignment,
   return S;
 }
 
-static void warnOrError(const Twine &Msg) {
-  if (Config->AllowMultipleDefinition)
-    warn(Msg);
-  else
-    error(Msg);
-}
-
 static void reportDuplicate(Symbol *Sym, InputFile *NewFile) {
-  warnOrError("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
-              toString(Sym->File) + "\n>>> defined in " + toString(NewFile));
+  if (!Config->AllowMultipleDefinition)
+    error("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
+          toString(Sym->File) + "\n>>> defined in " + toString(NewFile));
 }
 
 static void reportDuplicate(Symbol *Sym, InputFile *NewFile,
                             InputSectionBase *ErrSec, uint64_t ErrOffset) {
+  if (Config->AllowMultipleDefinition)
+    return;
+
   Defined *D = cast<Defined>(Sym);
   if (!D->Section || !ErrSec) {
     reportDuplicate(Sym, NewFile);
@@ -450,7 +447,7 @@ static void reportDuplicate(Symbol *Sym, InputFile *NewFile,
   if (!Src2.empty())
     Msg += Src2 + "\n>>>            ";
   Msg += Obj2;
-  warnOrError(Msg);
+  error(Msg);
 }
 
 Symbol *SymbolTable::addRegular(StringRef Name, uint8_t StOther, uint8_t Type,

lld/test/ELF/allow-multiple-definition.s

@@ -4,13 +4,13 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/allow-multiple-definition.s -o %t2
 # RUN: not ld.lld %t1 %t2 -o %t3
 # RUN: not ld.lld --allow-multiple-definition --no-allow-multiple-definition %t1 %t2 -o %t3
-# RUN: ld.lld --allow-multiple-definition %t1 %t2 -o %t3
-# RUN: ld.lld --allow-multiple-definition %t2 %t1 -o %t4
+# RUN: ld.lld --allow-multiple-definition --fatal-warnings %t1 %t2 -o %t3
+# RUN: ld.lld --allow-multiple-definition --fatal-warnings %t2 %t1 -o %t4
 # RUN: llvm-objdump -d %t3 | FileCheck %s
 # RUN: llvm-objdump -d %t4 | FileCheck -check-prefix=REVERT %s
 
-# RUN: ld.lld -z muldefs %t1 %t2 -o %t3
-# RUN: ld.lld -z muldefs %t2 %t1 -o %t4
+# RUN: ld.lld -z muldefs --fatal-warnings  %t1 %t2 -o %t3
+# RUN: ld.lld -z muldefs --fatal-warnings  %t2 %t1 -o %t4
 # RUN: llvm-objdump -d %t3 | FileCheck %s
 # RUN: llvm-objdump -d %t4 | FileCheck -check-prefix=REVERT %s