PNaCl: Add FlattenGlobals pass for simplifying global variable initializers

This pass converts initializers for global variables into a flattened
normal form which removes nested struct types and simplifies
ConstantExprs.

In the future, we might change the bitcode format to use the flattened
bytes+relocs representation for global initializers.  In that case, we
will be able to reuse the FlattenedConstant class in the bitcode
reader/writer for converting to and from this form.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3113
TEST=test/Transforms/NaCl/flatten-globals.ll

Review URL: https://codereview.chromium.org/14017011

1 files changed, 1 insertions, 0 deletions

diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 2998a047cf..ff6e5effeb 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -583,6 +583,7 @@ int main(int argc, char **argv) {
   initializeExpandTlsPass(Registry);
   initializeExpandTlsConstantExprPass(Registry);
   initializeExpandVarArgsPass(Registry);
+  initializeFlattenGlobalsPass(Registry);
   initializeGlobalCleanupPass(Registry);
   initializePNaClABIVerifyFunctionsPass(Registry);
   initializePNaClABIVerifyModulePass(Registry);