ELFObjectWriter: Don't de-duplicate STT_FILE symbols

Author: MaskRay

llvm/include/llvm/MC/MCAssembler.h

@@ -450,9 +450,6 @@ class MCAssembler {
   }
 
   void addFileName(StringRef FileName) {
-    for (const std::pair<std::string, size_t> &F : FileNames)
-      if (F.first == FileName)
-        return;
     FileNames.emplace_back(std::string(FileName), Symbols.size());
   }
 

llvm/lib/MC/ELFObjectWriter.cpp

@@ -725,7 +725,6 @@ void ELFWriter::computeSymbolTable(
   StrTabBuilder.finalize();
 
   // Symbols are required to be in lexicographic order.
-  //array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
   array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
 
   // Make the first STT_FILE precede previous local symbols.

llvm/test/MC/ELF/file.s

@@ -10,8 +10,9 @@
 # CHECK-NEXT:  7: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT     6 local1
 # CHECK-NEXT:  8: 0000000000000000     0 SECTION LOCAL  DEFAULT     8 bar1
 # CHECK-NEXT:  9: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT     8 local2
-# CHECK-NEXT: 10: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT     6 bar.c
-# CHECK-NEXT: 11: 0000000000000008     0 NOTYPE  GLOBAL DEFAULT     2 foo.c
+# CHECK-NEXT: 10: 0000000000000000     0 FILE    LOCAL  DEFAULT   ABS bar.c
+# CHECK-NEXT: 11: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT     6 bar.c
+# CHECK-NEXT: 12: 0000000000000008     0 NOTYPE  GLOBAL DEFAULT     2 foo.c
 
 .quad .text
 
@@ -34,3 +35,6 @@ local1:
 .section bar1,"a"
 local2:
 .quad bar1
+
+## STT_FILE symbols of the same name are not de-duplicated.
+.file "bar.c"