[LTO] Fix -save-temps in case -o is not specified.

Currently we create a file called .lto.bc. In UNIX,
ls(1) by default doesn't show up files starting with
a dot, as they're (only by convention) hidden.
This makes the output of -save-temps a little bit
hard to find. Use "a.out.lto.bc" instead if the
output file is not specified.

While here, change an existing -save-temps test to
exercise this more interesting behaviour.

llvm-svn: 265254

1 files changed, 7 insertions, 3 deletions

diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 0a5123c2daf..e828700a97e 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -434,14 +434,18 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   for (StringRef S : Config->Undefined)
     Symtab.addUndefinedOpt(S);
 
+  // -save-temps creates a file based on the output file name so we want
+  // to set it right before LTO. This code can't be moved to option parsing
+  // because linker scripts can override the output filename using the
+  // OUTPUT() directive.
+  if (Config->OutputFile.empty())
+    Config->OutputFile = "a.out";
+
   Symtab.addCombinedLtoObject();
 
   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)