Update ThinLTO test

[rdhindsa]

Summary

Updated thinLTO test to not include forward or backward slash for testing. (It was erroring out on windows)
Added code to not generate empty index files only if thinlto-index-only option is turned on.

[pcc]

LGTM

[grimar]

lld/ELF/LTO.cpp

199

This needs a test case.

Actually, this part should have been in a different patch from "Updated thinLTO test to not include forward or backward slash for testing." part.

[grimar]

lld/ELF/LTO.cpp

199

.. because fixing windows BB failures (I guess) is different from changing the functionality.

[pcc]

lld/ELF/LTO.cpp

199

Yes, this should have included a test. @rdhindsa can you please add one?

lld/ELF/LTO.cpp

 
 void BitcodeCompiler::add(BitcodeFile &F) {
   lto::InputFile &Obj = *F.Obj;
 
   std::string OldPrefix, NewPrefix;
   std::tie(OldPrefix, NewPrefix) = Config->ThinLTOPrefixReplace.split(';');
 
   // Create the empty files which, if indexed, will be overwritten later.
-  writeEmptyDistributedBuildOutputs(Obj.getName(), OldPrefix, NewPrefix, false);
+  if (Config->ThinLTOIndexOnly)
+    writeEmptyDistributedBuildOutputs(Obj.getName(), OldPrefix, NewPrefix,
+                                      false);
 
   unsigned SymNum = 0;
   std::vector<Symbol *> Syms = F.getSymbols();
   std::vector<lto::SymbolResolution> Resols(Syms.size());
 
   bool IsExecutable = !Config->Shared && !Config->Relocatable;
 
   // Provide a resolution to the LTO API for each symbol.

lld/test/ELF/lto/thinlto.ll

 ; NM: T f
 ; NM1: T f
 ; NM1-NOT: U g
 ; NM2: T g
 
 ; The backend index for this module contains summaries from itself and
 ; Inputs/thinlto.ll, as it imports from the latter.
 ; BACKEND1: <MODULE_STRTAB_BLOCK
-; BACKEND1-NEXT: <ENTRY {{.*}} record string = '{{.*}}/thinlto.ll.tmp{{.*}}.o'
-; BACKEND1-NEXT: <ENTRY {{.*}} record string = '{{.*}}/thinlto.ll.tmp{{.*}}.o'
+; BACKEND1-NEXT: <ENTRY {{.*}} record string = '{{.*}}thinlto.ll.tmp{{.*}}.o'
+; BACKEND1-NEXT: <ENTRY {{.*}} record string = '{{.*}}thinlto.ll.tmp{{.*}}.o'
 ; BACKEND1-NEXT: </MODULE_STRTAB_BLOCK
 ; BACKEND1: <GLOBALVAL_SUMMARY_BLOCK
 ; BACKEND1: <VERSION
 ; BACKEND1: <FLAGS
 ; BACKEND1: <VALUE_GUID op0={{1|2}} op1={{-3706093650706652785|-5300342847281564238}}
 ; BACKEND1: <VALUE_GUID op0={{1|2}} op1={{-3706093650706652785|-5300342847281564238}}
 ; BACKEND1: <COMBINED
 ; BACKEND1: <COMBINED
 ; BACKEND1: </GLOBALVAL_SUMMARY_BLOCK
 
 ; The backend index for Input/thinlto.ll contains summaries from itself only,
 ; as it does not import anything.
 ; BACKEND2: <MODULE_STRTAB_BLOCK
-; BACKEND2-NEXT: <ENTRY {{.*}} record string = '{{.*}}/thinlto.ll.tmp2.o'
+; BACKEND2-NEXT: <ENTRY {{.*}} record string = '{{.*}}thinlto.ll.tmp2.o'
 ; BACKEND2-NEXT: </MODULE_STRTAB_BLOCK
 ; BACKEND2-NEXT: <GLOBALVAL_SUMMARY_BLOCK
 ; BACKEND2-NEXT: <VERSION
 ; BACKEND2-NEXT: <FLAGS
 ; BACKEND2-NEXT: <VALUE_GUID op0=1 op1=-5300342847281564238
 ; BACKEND2-NEXT: <COMBINED
 ; BACKEND2-NEXT: </GLOBALVAL_SUMMARY_BLOCK