[strong] Implement strong mode semantics for the count operation.

src/mips/full-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
@@ skipping 5021 matching lines @@
     Register scratch1 = a1;
     Register scratch2 = t0;
     __ li(scratch1, Operand(Smi::FromInt(count_value)));
     __ AdduAndCheckForOverflow(v0, v0, scratch1, scratch2);
     __ BranchOnNoOverflow(&done, scratch2);
     // Call stub. Undo operation first.
     __ Move(v0, a0);
     __ jmp(&stub_call);
     __ bind(&slow);
   }
-  ToNumberStub convert_stub(isolate());
-  __ CallStub(&convert_stub);
-  PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
+  if (!is_strong(language_mode())) {
+    ToNumberStub convert_stub(isolate());
+    __ CallStub(&convert_stub);
+    PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
+  }
 
   // Save result for postfix expressions.
   if (expr->is_postfix()) {
     if (!context()->IsEffect()) {
       // Save the result on the stack. If we have a named or keyed property
       // we store the result under the receiver that is currently on top
       // of the stack.
       switch (assign_type) {
         case VARIABLE:
           __ push(v0);
@@ skipping 20 matching lines @@
 
   // Record position before stub call.
   SetSourcePosition(expr->position());
 
   Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), Token::ADD,
                                               strength(language_mode())).code();
   CallIC(code, expr->CountBinOpFeedbackId());
   patch_site.EmitPatchInfo();
   __ bind(&done);
 
+  if (is_strong(language_mode())) {
+    PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
+  }
   // Store the value returned in v0.
   switch (assign_type) {
     case VARIABLE:
       if (expr->is_postfix()) {
         { EffectContext context(this);
           EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
                                  Token::ASSIGN, expr->CountSlot());
           PrepareForBailoutForId(expr->AssignmentId(), TOS_REG);
           context.Plug(v0);
         }
@@ skipping 478 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS