Check for metadata in PNaCl ABI checker.

tools/opt/opt.cpp

Index: tools/opt/opt.cpp
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 26a5e4a3c171bd60d9c460540153f4945b0226a5..7a8ecad92831075bc90e584b4abddc5d89546ef0 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -586,8 +586,6 @@ int main(int argc, char **argv) {
   initializeExpandVarArgsPass(Registry);
   initializeFlattenGlobalsPass(Registry);
   initializeGlobalCleanupPass(Registry);
-  initializePNaClABIVerifyFunctionsPass(Registry);

[jvoung (off chromium), 2013/04/25 17:30:25]

I'm not sure how to pass a flag to these generic initialize*Pass() functions, so
I think we would need to do "Passes.add(createPNaCl...(ErrReporter,
PNaClABIAllowDebug));" below.  Would you prefer extra mods like that, or just
modify pnacl-ld to run "pnacl-abicheck" separately after the expand passes? (see
current driver change).  That does make the linking a little slower, which could
affect autoconf-type things...

[Mark Seaborn, 2013/04/25 18:11:19]

You could have a "static cl::opt<bool>" in PNaClABIVerify*.cpp. 
lib/Transforms/Utils/LowerInvoke.cpp has one for "-enable-correct-eh-support". 
It's icky having a global variable for this, but LLVM seems to like it that way.

Probably you can't have this cl::opt as static if you need this option for two
passes.  I'm not sure this really needs to be two separate passes, though?

[jvoung (off chromium), 2013/04/25 23:22:20]

I think it's separate for streaming -- one is a module-level pass that never
touches functions, and the other is a function-level pass.  Perhaps they can be
defined in the same file though...

Ended up extern'ing the commandline flag.  There's one case in
include/llvm/CodeGen/MachineScheduler.h "extern cl::opt<bool> ForceBottomUp;"
and a couple cases in lib/Target, but it is rare =/

[Derek Schuff, 2013/04/26 00:34:34]

On 2013/04/25 23:22:20, jvoung (cr) wrote:
The separation is for streaming. There are a few extern flag decls lying around.
Also in our MIPS port, Petar re-used the sfi-foo flags we had for ARM, which is
even worse because they are in different libraries. It's only by accident that
our CMake shared library build successfully links (it doesn't on mac).

-  initializePNaClABIVerifyModulePass(Registry);
   initializeResolveAliasesPass(Registry);
   initializeStripMetadataPass(Registry);
   // @LOCALMOD-END