MIPS64: VectorICs: keyed element loads were kicking out non-smi keys unnecessarily

Port 6689cc27ebe60685c025de9ae1f09919093f8213

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.

BUG=

Review URL: https://codereview.chromium.org/1025303005

Cr-Commit-Position: refs/heads/master@{#27383}

diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index 643ff5c..74477b5 100644 (file)
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -1380,12 +1380,8 @@ void LoadIndexedStringStub::Generate(MacroAssembler* masm) {
   Register result = v0;
   DCHECK(!scratch.is(receiver) && !scratch.is(index));
   DCHECK(!FLAG_vector_ics ||
-         (!scratch.is(VectorLoadICDescriptor::VectorRegister()) &&
-          result.is(VectorLoadICDescriptor::SlotRegister())));
+         !scratch.is(VectorLoadICDescriptor::VectorRegister()));
 
-  // StringCharAtGenerator doesn't use the result register until it's passed
-  // the different miss possibilities. If it did, we would have a conflict
-  // when FLAG_vector_ics is true.
   StringCharAtGenerator char_at_generator(receiver, index, scratch, result,
                                           &miss,  // When not a string.
                                           &miss,  // When not a number.
@@ -1396,7 +1392,7 @@ 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(
@@ -3089,7 +3085,7 @@ void CallICStub::GenerateMiss(MacroAssembler* masm) {
 
 
 void StringCharCodeAtGenerator::GenerateSlow(
-    MacroAssembler* masm,
+    MacroAssembler* masm, EmbedMode embed_mode,
     const RuntimeCallHelper& call_helper) {
   __ Abort(kUnexpectedFallthroughToCharCodeAtSlowCase);
 
@@ -3103,7 +3099,12 @@ void StringCharCodeAtGenerator::GenerateSlow(
               DONT_DO_SMI_CHECK);
   call_helper.BeforeCall(masm);
   // Consumed by runtime conversion function:
-  __ Push(object_, index_);
+  if (FLAG_vector_ics && embed_mode == PART_OF_IC_HANDLER) {
+    __ Push(VectorLoadICDescriptor::VectorRegister(),
+            VectorLoadICDescriptor::SlotRegister(), object_, index_);
+  } else {
+    __ Push(object_, index_);
+  }
   if (index_flags_ == STRING_INDEX_IS_NUMBER) {
     __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
   } else {
@@ -3116,7 +3117,12 @@ void StringCharCodeAtGenerator::GenerateSlow(
   // have a chance to overwrite it.
 
   __ Move(index_, v0);
-  __ pop(object_);
+  if (FLAG_vector_ics && embed_mode == PART_OF_IC_HANDLER) {
+    __ Pop(VectorLoadICDescriptor::SlotRegister(),
+           VectorLoadICDescriptor::VectorRegister(), object_);
+  } else {
+    __ pop(object_);
+  }
   // Reload the instance type.
   __ ld(result_, FieldMemOperand(object_, HeapObject::kMapOffset));
   __ lbu(result_, FieldMemOperand(result_, Map::kInstanceTypeOffset));

diff --git a/src/mips64/full-codegen-mips64.cc b/src/mips64/full-codegen-mips64.cc
index 7d1261f..0f157ec 100644 (file)
--- a/src/mips64/full-codegen-mips64.cc
+++ b/src/mips64/full-codegen-mips64.cc
@@ -4111,7 +4111,7 @@ void FullCodeGenerator::EmitStringCharCodeAt(CallRuntime* expr) {
   __ jmp(&done);
 
   NopRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm_, call_helper);
+  generator.GenerateSlow(masm_, NOT_PART_OF_IC_HANDLER, call_helper);
 
   __ bind(&done);
   context()->Plug(result);
@@ -4160,7 +4160,7 @@ void FullCodeGenerator::EmitStringCharAt(CallRuntime* expr) {
   __ jmp(&done);
 
   NopRuntimeCallHelper call_helper;
-  generator.GenerateSlow(masm_, call_helper);
+  generator.GenerateSlow(masm_, NOT_PART_OF_IC_HANDLER, call_helper);
 
   __ bind(&done);
   context()->Plug(result);