PPC: VectorICs: keyed element loads were kicking out non-smi keys unnecessarily

Port 6689cc27

Original commit message:
Handlers should be in charge of this work. The change uncovered a bug in
vector-ics related to keyed loads into strings. It's important for
StringCharCodeAtGenerator, a helper used in full code and in
LoadIndexedStringStub (a handler) to protect the vector and slot registers
when it makes a runtime call to convert a HeapNumber to a Smi.

It's still possible for the handler to MISS after this call, perhaps due
to out of bounds access. In that case, the vector and slot registers need
to be delivered safely to the MISS handler.

R=mbrandy@us.ibm.com, svenpanne@chromium.org

BUG=

Review URL: https://codereview.chromium.org/1029413002

Cr-Commit-Position: refs/heads/master@{#27430}

src/ppc/code-stubs-ppc.cc

@@ -1594,7 +1594,7 @@ void LoadIndexedStringStub::Generate(MacroAssembler* masm) {
   __ Ret();
 
   StubRuntimeCallHelper call_helper;
-  char_at_generator.GenerateSlow(masm, call_helper);
+  char_at_generator.GenerateSlow(masm, PART_OF_IC_HANDLER, call_helper);
 
   __ bind(&miss);
   PropertyAccessCompiler::TailCallBuiltin(
@@ -3079,7 +3079,8 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
 
 
 void StringCharCodeAtGenerator::GenerateSlow(
-    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
+    MacroAssembler* masm, EmbedMode embed_mode,
+    const RuntimeCallHelper& call_helper) {
   __ Abort(kUnexpectedFallthroughToCharCodeAtSlowCase);
 
   // Index is not a smi.
@@ -3088,8 +3089,13 @@ void StringCharCodeAtGenerator::GenerateSlow(
   __ CheckMap(index_, result_, Heap::kHeapNumberMapRootIndex, index_not_number_,
               DONT_DO_SMI_CHECK);
   call_helper.BeforeCall(masm);
-  __ push(object_);
-  __ push(index_);  // Consumed by runtime conversion function.
+  if (FLAG_vector_ics && embed_mode == PART_OF_IC_HANDLER) {
+    __ Push(VectorLoadICDescriptor::VectorRegister(),
+            VectorLoadICDescriptor::SlotRegister(), object_, index_);
+  } else {
+    // index_ is consumed by runtime conversion function.
+    __ Push(object_, index_);
+  }
   if (index_flags_ == STRING_INDEX_IS_NUMBER) {
     __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
   } else {
@@ -3100,7 +3106,12 @@ void StringCharCodeAtGenerator::GenerateSlow(
   // Save the conversion result before the pop instructions below
   // have a chance to overwrite it.
   __ Move(index_, r3);
-  __ pop(object_);
+  if (FLAG_vector_ics && embed_mode == PART_OF_IC_HANDLER) {
+    __ Pop(VectorLoadICDescriptor::VectorRegister(),
+           VectorLoadICDescriptor::SlotRegister(), object_);
+  } else {
+    __ pop(object_);
+  }
   // Reload the instance type.
   __ LoadP(result_, FieldMemOperand(object_, HeapObject::kMapOffset));
   __ lbz(result_, FieldMemOperand(result_, Map::kInstanceTypeOffset));
@@ -4778,7 +4789,6 @@ void VectorRawKeyedLoadStub::GenerateImpl(MacroAssembler* masm, bool in_frame) {
   __ LoadP(scratch1, FieldMemOperand(feedback, HeapObject::kMapOffset));
   __ CompareRoot(scratch1, Heap::kWeakCellMapRootIndex);
   __ bne(&try_array);
-  __ JumpIfNotSmi(key, &miss);
   HandleMonomorphicCase(masm, receiver, key, vector, slot, feedback, scratch1,
                         &miss);
 
@@ -4786,9 +4796,8 @@ void VectorRawKeyedLoadStub::GenerateImpl(MacroAssembler* masm, bool in_frame) {
   // Is it a fixed array?
   __ CompareRoot(scratch1, Heap::kFixedArrayMapRootIndex);
   __ bne(&not_array);
-  // We have a polymorphic element handler.
-  __ JumpIfNotSmi(key, &miss);
 
+  // We have a polymorphic element handler.
   Label polymorphic, try_poly_name;
   __ bind(&polymorphic);
   HandleArrayCases(masm, receiver, key, vector, slot, feedback, scratch1, r9,

src/ppc/full-codegen-ppc.cc

@@ -4105,7 +4105,7 @@ void FullCodeGenerator::EmitStringCharCodeAt(CallRuntime* expr) {
   __ b(&done);
 
   NopRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm_, call_helper);
+  generator.GenerateSlow(masm_, NOT_PART_OF_IC_HANDLER, call_helper);
 
   __ bind(&done);
   context()->Plug(result);
@@ -4147,7 +4147,7 @@ void FullCodeGenerator::EmitStringCharAt(CallRuntime* expr) {
   __ b(&done);
 
   NopRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm_, call_helper);
+  generator.GenerateSlow(masm_, NOT_PART_OF_IC_HANDLER, call_helper);
 
   __ bind(&done);
   context()->Plug(result);