ELF: Report duplicate symbols as many as possible instead of the first one.

[• rafael]

LGTM

ELF/SymbolTable.cpp

50

Why not use FileP?

[ruiu]

ELF/SymbolTable.cpp

50

Done.

ELF/Driver.cpp

if (Config->EMachine == EM_MIPS) {
     // so that it points to an absolute address which is relative to GOT.
     // See "Global Data Symbols" in Chapter 6 in the following document:
     // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
     Symtab.addAbsolute("_gp", ElfSym<ELFT>::MipsGp);
   }
 
   for (std::unique_ptr<InputFile> &F : Files)
     Symtab.addFile(std::move(F));
+  if (HasError)
+    return; // There were duplicate symbols or incompatible files
 
   for (StringRef S : Config->Undefined)
     Symtab.addUndefinedOpt(S);
 
   for (auto *Arg : Args.filtered(OPT_wrap))
     Symtab.wrap(Arg->getValue());
 
   if (Config->OutputFile.empty())
     Config->OutputFile = "a.out";
 
   // Write the result to the file.
   Symtab.scanShlibUndefined();
   if (Config->GcSections)
     markLive<ELFT>(&Symtab);
   writeResult<ELFT>(&Symtab);
 }

ELF/SymbolTable.cpp

 using namespace llvm::ELF;
 
 using namespace lld;
 using namespace lld::elf2;
 
 // All input object files must be for the same architecture
 // (e.g. it does not make sense to link x86 object files with
 // MIPS object files.) This function checks for that fatal.
-template <class ELFT>
-static void checkCompatibility(InputFile *FileP) {
+template <class ELFT> static bool isCompatible(InputFile *FileP) {
   auto *F = dyn_cast<ELFFileBase<ELFT>>(FileP);
   if (!F)
-    return;
+    return true;
   if (F->getELFKind() == Config->EKind && F->getEMachine() == Config->EMachine)
-    return;
+    return true;
   StringRef A = F->getName();
   StringRef B = Config->Emulation;
   if (B.empty())
     B = Config->FirstElf->getName();
-  fatal(A + " is incompatible with " + B);
+  error(A + " is incompatible with " + B);
+  return false;
 }
 
 // Add symbols in File to the symbol table.
 template <class ELFT>
 void SymbolTable<ELFT>::addFile(std::unique_ptr<InputFile> File) {
+  if (!isCompatible<ELFT>(File.get()))
+    return;
   InputFile *FileP = File.get();
-  checkCompatibility<ELFT>(FileP);
 
   // .a file
   if (auto *F = dyn_cast<ArchiveFile>(FileP)) {
     ArchiveFiles.emplace_back(cast<ArchiveFile>(File.release()));
     F->parse();
     for (Lazy &Sym : F->getLazySymbols())
       addLazy(&Sym);
     return;
if (auto *Undef = dyn_cast<Undefined>(New)) {
       return;
     }
     // Found a definition for something also in an archive.
     // Ignore the archive definition.
     Sym->Body = New;
     return;
   }
 
-  if (New->isTls() != Existing->isTls())
-    fatal("TLS attribute mismatch for symbol: " + conflictMsg(Existing, New));
+  if (New->isTls() != Existing->isTls()) {
+    error("TLS attribute mismatch for symbol: " + conflictMsg(Existing, New));
+    return;
+  }
 
   // compare() returns -1, 0, or 1 if the lhs symbol is less preferable,
   // equivalent (conflicting), or more preferable, respectively.
   int Comp = Existing->compare<ELFT>(New);
   if (Comp == 0) {
     std::string S = "duplicate symbol: " + conflictMsg(Existing, New);
-    if (!Config->AllowMultipleDefinition)
-      fatal(S);
+    if (Config->AllowMultipleDefinition)
       warning(S);
+    else
+      error(S);
     return;
   }
   if (Comp < 0)
     Sym->Body = New;
 }
 
 // Find an existing symbol or create and insert a new one.
 template <class ELFT> Symbol *SymbolTable<ELFT>::insert(SymbolBody *New) {

test/ELF/conflict.s

 # REQUIRES: x86
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 # RUN: not ld.lld %t %t -o %t2 2>&1 | FileCheck -check-prefix=DEMANGLE %s
 
 # RUN: not ld.lld %t %t -o %t2 --no-demangle 2>&1 | \
 # RUN:   FileCheck -check-prefix=NO_DEMANGLE %s
 
 # DEMANGLE:    duplicate symbol: {{mul\(double, double\)|_Z3muldd}} in
+# DEMANGLE:    duplicate symbol: foo in
+
 # NO_DEMANGLE: duplicate symbol: _Z3muldd in
+# NO_DEMANGLE: duplicate symbol: foo in
 
-.globl _Z3muldd
+.globl _Z3muldd, foo
 _Z3muldd:
+foo:
   mov $60, %rax
   mov $42, %rdi
   syscall