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 STRUCT_ANON in bitcode files PNaClVersion==2.

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

Review URL: https://codereview.chromium.org/23455023

3 files changed, 15 insertions, 27 deletions

diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
index aac03678d1..1e524db3de 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
@@ -489,6 +489,10 @@ bool NaClBitcodeReader::ParseTypeTableBody() {
       break;
     }
     case naclbitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
+      // Deprecated. Only exists in early PNaCl version 1 bitcode files.
+      // TODO(kschimpf) Remove this as soon as is feasible.
+      if (GetPNaClVersion() >= 2)
+        return Error("Struct types not supported in PNaCl bitcode");
       if (Record.size() < 1)
         return Error("Invalid STRUCT type record");
       SmallVector<Type*, 8> EltTys;
diff --git a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
index 4a6a454796..3d5d50cc20 100644
--- a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
+++ b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
@@ -94,7 +94,6 @@ enum {
   // TYPE_BLOCK_ID_NEW abbrev id's.
   TYPE_POINTER_ABBREV = naclbitc::FIRST_APPLICATION_ABBREV,
   TYPE_FUNCTION_ABBREV,
-  TYPE_STRUCT_ANON_ABBREV,
   TYPE_ARRAY_ABBREV,
   TYPE_MAX_ABBREV = TYPE_ARRAY_ABBREV
 };
@@ -201,15 +200,6 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
   if (TYPE_FUNCTION_ABBREV != Stream.EmitAbbrev(Abbv))
     llvm_unreachable("Unexpected abbrev ordering!");
 
-  // Abbrev for TYPE_CODE_STRUCT_ANON.
-  Abbv = new NaClBitCodeAbbrev();
-  Abbv->Add(NaClBitCodeAbbrevOp(naclbitc::TYPE_CODE_STRUCT_ANON));
-  Abbv->Add(NaClBitCodeAbbrevOp(NaClBitCodeAbbrevOp::Fixed, 1));  // ispacked
-  Abbv->Add(NaClBitCodeAbbrevOp(NaClBitCodeAbbrevOp::Array));
-  Abbv->Add(NaClBitCodeAbbrevOp(NaClBitCodeAbbrevOp::Fixed, NumBits));
-  if (TYPE_STRUCT_ANON_ABBREV != Stream.EmitAbbrev(Abbv))
-    llvm_unreachable("Unexpected abbrev ordering!");
-
   // Abbrev for TYPE_CODE_ARRAY.
   Abbv = new NaClBitCodeAbbrev();
   Abbv->Add(NaClBitCodeAbbrevOp(naclbitc::TYPE_CODE_ARRAY));
@@ -261,23 +251,8 @@ static void WriteTypeTable(const NaClValueEnumerator &VE,
       AbbrevToUse = TYPE_FUNCTION_ABBREV;
       break;
     }
-    case Type::StructTyID: {
-      StructType *ST = cast<StructType>(T);
-      // STRUCT: [ispacked, eltty x N]
-      TypeVals.push_back(ST->isPacked());
-      // Output all of the element types.
-      for (StructType::element_iterator I = ST->element_begin(),
-           E = ST->element_end(); I != E; ++I)
-        TypeVals.push_back(VE.getTypeID(*I));
-
-      if (ST->isLiteral()) {
-        Code = naclbitc::TYPE_CODE_STRUCT_ANON;
-        AbbrevToUse = TYPE_STRUCT_ANON_ABBREV;
-      } else {
-        report_fatal_error("Non-anon structs not supported in PNaCl bitcode");
-      }
-      break;
-    }
+    case Type::StructTyID:
+      report_fatal_error("Struct types are not supported in PNaCl bitcode");
     case Type::ArrayTyID: {
       ArrayType *AT = cast<ArrayType>(T);
       // ARRAY: [numelts, eltty]
diff --git a/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp b/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
index 5dbc525eec..be31779a3a 100644
--- a/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
+++ b/lib/Bitcode/NaCl/Writer/NaClValueEnumerator.cpp
@@ -90,6 +90,10 @@ 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 (IsElidedCast(I))
+          continue;
+
         for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
              OI != E; ++OI) {
           EnumerateOperandType(*OI);
@@ -357,6 +361,11 @@ 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)) {