[stubs] Fix some CodeStubAssembler macros and adds a bitcast in the ToObjectStub.

This makes the MachineGraphVerifier happy with the stub.

R=jarin@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2394193002
Cr-Commit-Position: refs/heads/master@{#40154}

src/code-stub-assembler.cc

@@ -38,7 +38,7 @@ void CodeStubAssembler::Assert(Node* condition) {
 #endif
 }
 
-Node* CodeStubAssembler::NoContextConstant() { return SmiConstant(Smi::kZero); }
+Node* CodeStubAssembler::NoContextConstant() { return NumberConstant(0); }
 
 #define HEAP_CONSTANT_ACCESSOR(rootName, name)     \
   Node* CodeStubAssembler::name##Constant() {      \
@@ -611,19 +611,17 @@ Node* CodeStubAssembler::AllocateRawUnaligned(Node* size_in_bytes,
          &no_runtime_call);
 
   Bind(&runtime_call);
-  // AllocateInTargetSpace does not use the context.
-  Node* context = SmiConstant(Smi::kZero);
-
   Node* runtime_result;
   if (flags & kPretenured) {
     Node* runtime_flags = SmiConstant(
         Smi::FromInt(AllocateDoubleAlignFlag::encode(false) |
                      AllocateTargetSpace::encode(AllocationSpace::OLD_SPACE)));
-    runtime_result = CallRuntime(Runtime::kAllocateInTargetSpace, context,
-                                 SmiTag(size_in_bytes), runtime_flags);
+    runtime_result =
+        CallRuntime(Runtime::kAllocateInTargetSpace, NoContextConstant(),
+                    SmiTag(size_in_bytes), runtime_flags);
   } else {
-    runtime_result = CallRuntime(Runtime::kAllocateInNewSpace, context,
-                                 SmiTag(size_in_bytes));
+    runtime_result = CallRuntime(Runtime::kAllocateInNewSpace,
+                                 NoContextConstant(), SmiTag(size_in_bytes));
   }
   result.Bind(runtime_result);
   Goto(&merge_runtime);

src/compiler/code-assembler.cc

@@ -107,7 +107,7 @@ Node* CodeAssembler::NumberConstant(double value) {
 }
 
 Node* CodeAssembler::SmiConstant(Smi* value) {
-  return IntPtrConstant(bit_cast<intptr_t>(value));
+  return BitcastWordToTaggedSigned(IntPtrConstant(bit_cast<intptr_t>(value)));
 }
 
 Node* CodeAssembler::HeapConstant(Handle<HeapObject> object) {

test/unittests/interpreter/interpreter-assembler-unittest.cc

@@ -538,9 +538,9 @@ TARGET_TEST_F(InterpreterAssemblerTest, SmiTag) {
   TRACED_FOREACH(interpreter::Bytecode, bytecode, kBytecodes) {
     InterpreterAssemblerForTest m(this, bytecode);
     Node* value = m.Int32Constant(44);
-    EXPECT_THAT(m.SmiTag(value),
-                IsIntPtrConstant(static_cast<intptr_t>(44)
-                                 << (kSmiShiftSize + kSmiTagSize)));
+    EXPECT_THAT(m.SmiTag(value), IsBitcastWordToTaggedSigned(IsIntPtrConstant(
+                                     static_cast<intptr_t>(44)
+                                     << (kSmiShiftSize + kSmiTagSize))));
     EXPECT_THAT(m.SmiUntag(value),
                 IsWordSar(IsBitcastTaggedToWord(value),
                           IsIntPtrConstant(kSmiShiftSize + kSmiTagSize)));