Reapply "Change -save-temps to emit unoptimized bitcode files."

This reapplies r224503 along with a fix for compiling Fortran by having the
clang driver invoke gcc (see r224546, where it was reverted). I have added
a testcase for that as well.

Original commit message:
It is often convenient to use -save-temps to collect the intermediate
results of a compilation, e.g., when triaging a bug report. Besides the
temporary files for preprocessed source and assembly code, this adds the
unoptimized bitcode files as well.

This adds a new BackendJobAction, which is mostly mechanical, to run after
the CompileJobAction. When not using -save-temps, the BackendJobAction is
combined into one job with the CompileJobAction, similar to the way the
integrated assembler is handled. I've implemented this entirely as a
driver change, so under the hood, it is just using -disable-llvm-optzns
to get the unoptimized bitcode.

Based in part on a patch by Steven Wu.
rdar://problem/18909437

llvm-svn: 224688

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 6734ce7..2bcfecf 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -129,6 +129,7 @@ Tool *ToolChain::getTool(Action::ActionClass AC) const {
   case Action::AnalyzeJobClass:
   case Action::MigrateJobClass:
   case Action::VerifyPCHJobClass:
+  case Action::BackendJobClass:
     return getClang();
   }