[MC] Update Rootfile in AsmStreamer

[niravd]

Summary

Update TableRootFile in MCAsmStreamer allowing marginal improvement in
sharing of file information. This is has no semantic change , but
seems but it nominally reduces the differences between textual
assembly and object output paths.

[niravd]

Obsolete.

llvm/lib/MC/MCAsmStreamer.cpp

void MCAsmStreamer::emitDwarfFile0Directive(StringRef Directory,
                                             MD5::MD5Result *Checksum,
                                             Optional<StringRef> Source,
                                             unsigned CUID) {
   assert(CUID == 0);
   // .file 0 is new for DWARF v5.
   if (getContext().getDwarfVersion() < 5)
     return;
 
+  MCStreamer::emitDwarfFile0Directive(Directory, Filename, Checksum, Source,
+                                      CUID);
+
   SmallString<128> Str;
   raw_svector_ostream OS1(Str);
   printDwarfFileDirective(0, Directory, Filename, Checksum, Source,
                           UseDwarfDirectory, OS1);
 
   if (MCTargetStreamer *TS = getTargetStreamer())
     TS->emitDwarfFileDirective(OS1.str());
   else

llvm/test/CodeGen/Generic/dwarf-md5.ll

 ; MD5 checksums provided by IR should be passed through to asm.
 ; They'll be emitted to an object file only for DWARF 5 or later.
 
 ; Darwin clamps the line table at DWARF v2 so XFAIL this test.
 ; XFAIL: darwin
 
 ; REQUIRES: object-emission
 ; RUN: %llc_dwarf -dwarf-version 4 -filetype=asm -o - %s | FileCheck %s --check-prefixes=ASM,ASM-4
 ; RUN: %llc_dwarf -dwarf-version 5 -filetype=asm -o - %s | FileCheck %s --check-prefixes=ASM,ASM-5
 ; RUN: %llc_dwarf -dwarf-version 4 -filetype=obj -o %t4.o %s
 ; RUN: llvm-dwarfdump -debug-line %t4.o | FileCheck %s --check-prefix=OBJ
 ; RUN: %llc_dwarf -dwarf-version 5 -filetype=obj -o %t5.o %s
 ; RUN: llvm-dwarfdump -debug-line %t5.o | FileCheck %s --check-prefixes=OBJ,OBJ-5
 
 ; ASM-4-NOT: .file 0
 ; ASM-5: .file 0 "/scratch{{.*[/\\]}}t.c" md5 0x00000000000000000000000000000000
-; ASM: .file 1 "/scratch{{.*[/\\]}}t1.h"
+; ASM: .file 1 "{{.*}}t1.h"
 ; ASM-4-NOT:  md5
 ; ASM-5-SAME: md5 0x11111111111111111111111111111111
-; ASM: .file 2 "/scratch{{.*[/\\]}}t2.h"
+; ASM: .file 2 "{{.*}}t2.h"
 ; ASM-4-NOT:  md5
 ; ASM-5-SAME: md5 0x22222222222222222222222222222222
 
 ; OBJ-5: file_names[ 0]:
 ; OBJ-5-NEXT: name: "t.c"
 ; OBJ-5-NEXT: dir_index: 0
 ; OBJ-5-NEXT: md5_checksum: 00000000000000000000000000000000
 ; OBJ: file_names[ 1]:

llvm/test/CodeGen/Generic/dwarf-source.ll

 ; Source text provided by IR should be passed through to asm.
 ; It is emitted to an object file only for DWARF 5 or later.
 
 ; Darwin clamps the line table at DWARF v2 so XFAIL this test.
 ; XFAIL: darwin
 
 ; REQUIRES: object-emission
-; RUN: %llc_dwarf -dwarf-version 4 -filetype=asm -o - %s | FileCheck %s --check-prefix=ASM
-; RUN: %llc_dwarf -dwarf-version 5 -filetype=asm -o - %s | FileCheck %s --check-prefixes=ASM,ASM-5
+; RUN: %llc_dwarf -dwarf-version 4 -filetype=asm -o - %s | FileCheck %s --check-prefix=ASM-4
+; RUN: %llc_dwarf -dwarf-version 5 -filetype=asm -o - %s | FileCheck %s --check-prefixes=ASM-5
 ; RUN: %llc_dwarf -dwarf-version 4 -filetype=obj -o %t4.o %s
 ; RUN: llvm-dwarfdump -debug-line %t4.o | FileCheck %s --check-prefixes=OBJ,OBJ-4
 ; RUN: %llc_dwarf -dwarf-version 5 -filetype=obj -o %t5.o %s
 ; RUN: llvm-dwarfdump -debug-line %t5.o | FileCheck %s --check-prefixes=OBJ,OBJ-5
 
+; ASM-4: .file 1 "/test{{.*[/\\]}}t1.h" source "11111111111111111111111111111111"
+; ASM-4: .file 2 "/test{{.*[/\\]}}t2.h" source "22222222222222222222222222222222"
+
 ; ASM-5: .file 0 "/test{{.*[/\\]}}t.c" source "00000000000000000000000000000000"
-; ASM: .file 1 "/test{{.*[/\\]}}t1.h" source "11111111111111111111111111111111"
-; ASM: .file 2 "/test{{.*[/\\]}}t2.h" source "22222222222222222222222222222222"
+; ASM-5: .file 1 "t1.h" source "11111111111111111111111111111111"
+; ASM-5: .file 2 "t2.h" source "22222222222222222222222222222222"
 
 ; OBJ-5: file_names[ 0]:
 ; OBJ-5-NEXT: name: "t.c"
 ; OBJ-5-NEXT: dir_index: 0
 ; OBJ-5-NEXT: source: "00000000000000000000000000000000"
 ; OBJ: file_names[ 1]:
 ; OBJ-NEXT: name: "t1.h"
 ; OBJ-NEXT: dir_index: 0