PNaCl ABI: Promote illegal integer types

This pass (mostly) legalizes integer types by promoting them.
It has some limitations (e.g. it can't change function types)
but it is more than sufficient for what clang and SROA generate.

A more significant limitation of promotion is that packed
bitfields of size > 64 bits are still not handled. There are
none in our tests (other than callingconv_case_by_case which
doesn't require a stable pexe) but we will want to either
handle them by correctly expanding them, or find a better way
to error out.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3360
[email protected], [email protected]

Review URL: https://codereview.chromium.org/14569012

Author: dschuff

include/llvm/InitializePasses.h

@@ -290,6 +290,7 @@ void initializeInsertDivideCheckPass(PassRegistry&);
 void initializeNaClCcRewritePass(PassRegistry&);
 void initializePNaClABIVerifyModulePass(PassRegistry&);
 void initializePNaClABIVerifyFunctionsPass(PassRegistry&);
+void initializePromoteIntegersPass(PassRegistry&);
 void initializeResolveAliasesPass(PassRegistry&);
 void initializeStripMetadataPass(PassRegistry&);
 // @LOCALMOD-END

include/llvm/Transforms/NaCl.h

@@ -28,6 +28,7 @@ ModulePass *createExpandTlsConstantExprPass();
 ModulePass *createExpandVarArgsPass();
 ModulePass *createFlattenGlobalsPass();
 ModulePass *createGlobalCleanupPass();
+FunctionPass *createPromoteIntegersPass();
 ModulePass *createResolveAliasesPass();
 ModulePass *createStripMetadataPass();
 FunctionPass *createInsertDivideCheckPass();

lib/Transforms/NaCl/CMakeLists.txt

@@ -10,6 +10,7 @@ add_llvm_library(LLVMNaClTransforms
   InsertDivideCheck.cpp
   FlattenGlobals.cpp
   GlobalCleanup.cpp
+  PromoteIntegers.cpp
   StripMetadata.cpp
   )