Remove generating STRUCT_ANON records in PNaCl bitcode files.

Don't generate types for elided cast instructions, since they
are never put into the bitcode file. In addition, do not generate
a type id for the types of global variables, because they are never
needed. Don't allow and STRUCT records in bitcode files
when PNaClVersion==2.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3648
R=mseaborn@chromium.org

Review URL: https://codereview.chromium.org/23431008

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp b/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
index 8cfdf13240..8e35f59909 100644
--- a/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
+++ b/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
@@ -89,6 +89,10 @@ NaClValueEnumerator::NaClValueEnumerator(const Module *M, uint32_t PNaClVersion)
 
     for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
       for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
+        // Don't generate types for elided pointer casts!
+        if (I == ElideCasts(I))
+          continue;
+
         for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
              OI != E; ++OI) {
           EnumerateOperandType(*OI);
@@ -356,6 +360,11 @@ void NaClValueEnumerator::EnumerateType(Type *Ty, bool InsideOptimizeTypes) {
 // Enumerate the types for the specified value.  If the value is a constant,
 // walk through it, enumerating the types of the constant.
 void NaClValueEnumerator::EnumerateOperandType(const Value *V) {
+  // Note: We intentionally don't create a type id for global variables,
+  // since the type is automatically generated by the reader before any
+  // use of the global variable.
+  if (isa<GlobalVariable>(V)) return;
+
   EnumerateType(V->getType());
 
   if (const Constant *C = dyn_cast<Constant>(V)) {