PNaCl bitcode: Strip pointer types from intrinsic declarations' parameters

Change the writer to strip pointer types from intrinsics' argument and
return types, replacing them with i32.  This simplifies the PNaCl
bitcode format so that pointer types don't need to be represented
here.

Change the reader to restore the pointer types so that the intrinsic
declarations pass the LLVM and PNaCl verifiers.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3671
TEST=intrinsic tests in call-elide.ll
  + intrinsic-pointer-args.ll
  + run small_tests with bitcode v2 enabled

Review URL: https://codereview.chromium.org/23793005

1 files changed, 63 insertions, 0 deletions

diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
index 937012feb8..8b8e9072a8 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
@@ -177,6 +177,10 @@ void NaClBitcodeReaderValueList::AssignGlobalVar(GlobalVariable *GV,
   ValuePtrs[Idx] = GV;
 }
 
+void NaClBitcodeReaderValueList::OverwriteValue(Value *V, unsigned Idx) {
+  ValuePtrs[Idx] = V;
+}
+
 Value *NaClBitcodeReaderValueList::getValueFwdRef(unsigned Idx) {
   if (Idx >= size())
     return 0;
@@ -771,6 +775,60 @@ bool NaClBitcodeReader::GlobalCleanup() {
   return false;
 }
 
+FunctionType *NaClBitcodeReader::AddPointerTypesToIntrinsicType(
+    StringRef Name, FunctionType *FTy) {
+  Type *ReturnTy = FTy->getReturnType();
+  SmallVector<Type *, 8> ArgTypes(FTy->param_begin(), FTy->param_end());
+
+  // Ideally we wouldn't need a list of supported intrinsics here, but
+  // Intrinsic::* doesn't provide a function for recovering the
+  // expected type of an intrinsic given its full name.
+  // TODO(mseaborn): We could reuse the intrinsic list from
+  // PNaClABIVerifyModule.cpp here.
+  if (Name == "llvm.nacl.read.tp" ||
+      Name == "llvm.stacksave") {
+    ReturnTy = Type::getInt8PtrTy(Context);
+  } else if (Name == "llvm.nacl.setjmp" ||
+             Name == "llvm.nacl.longjmp" ||
+             Name == "llvm.stackrestore" ||
+             Name.startswith("llvm.memset.")) {
+    assert(ArgTypes.size() >= 1);
+    ArgTypes[0] = Type::getInt8PtrTy(Context);
+  } else if (Name.startswith("llvm.memcpy.") ||
+             Name.startswith("llvm.memmove.")) {
+    assert(ArgTypes.size() >= 2);
+    ArgTypes[0] = Type::getInt8PtrTy(Context);
+    ArgTypes[1] = Type::getInt8PtrTy(Context);
+  } else if (Name.startswith("llvm.nacl.atomic.load.") ||
+             Name.startswith("llvm.nacl.atomic.cmpxchg.")) {
+    assert(ArgTypes.size() >= 1);
+    ArgTypes[0] = ReturnTy->getPointerTo();
+  } else if (Name.startswith("llvm.nacl.atomic.store.")) {
+    assert(ArgTypes.size() >= 2);
+    ArgTypes[1] = ArgTypes[0]->getPointerTo();
+  } else if (Name.startswith("llvm.nacl.atomic.rmw.")) {
+    assert(ArgTypes.size() >= 3);
+    ArgTypes[1] = ArgTypes[2]->getPointerTo();
+  }
+  return FunctionType::get(ReturnTy, ArgTypes, false);
+}
+
+void NaClBitcodeReader::AddPointerTypesToIntrinsicParams() {
+  for (unsigned Index = 0, E = ValueList.size(); Index < E; ++Index) {
+    if (Function *Func = dyn_cast<Function>(ValueList[Index])) {
+      if (Func->isIntrinsic()) {
+        FunctionType *FTy = AddPointerTypesToIntrinsicType(
+            Func->getName(), Func->getFunctionType());
+        Function *NewIntrinsic = Function::Create(
+            FTy, GlobalValue::ExternalLinkage, "", TheModule);
+        NewIntrinsic->takeName(Func);
+        ValueList.OverwriteValue(NewIntrinsic, Index);
+        Func->eraseFromParent();
+      }
+    }
+  }
+}
+
 bool NaClBitcodeReader::ParseModule(bool Resume) {
   DEBUG(dbgs() << "-> ParseModule\n");
   if (Resume)
@@ -816,6 +874,11 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
         if (ParseValueSymbolTable())
           return true;
         SeenValueSymbolTable = true;
+        if (GetPNaClVersion() >= 2) {
+          // Now that we know the names of the intrinsics, we can add
+          // pointer types to the intrinsic declarations' types.
+          AddPointerTypesToIntrinsicParams();
+        }
         break;
       case naclbitc::FUNCTION_BLOCK_ID:
         // If this is the first function body we've seen, reverse the