[strong] Disallow implicit conversions for comparison

src/mips/code-stubs-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
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 75 matching lines @@
 
 void InternalArrayNArgumentsConstructorStub::InitializeDescriptor(
     CodeStubDescriptor* descriptor) {
   InitializeInternalArrayConstructorDescriptor(isolate(), descriptor, -1);
 }
 
 
 #define __ ACCESS_MASM(masm)
 
 
-static void EmitIdenticalObjectComparison(MacroAssembler* masm,
-                                          Label* slow,
-                                          Condition cc);
+static void EmitIdenticalObjectComparison(MacroAssembler* masm, Label* slow,
+                                          Condition cc, bool strong);
 static void EmitSmiNonsmiComparison(MacroAssembler* masm,
                                     Register lhs,
                                     Register rhs,
                                     Label* rhs_not_nan,
                                     Label* slow,
                                     bool strict);
 static void EmitStrictTwoHeapObjectCompare(MacroAssembler* masm,
                                            Register lhs,
                                            Register rhs);
 
@@ skipping 160 matching lines @@
   __ bind(&done);
 
   __ Pop(scratch, scratch2, scratch3);
   __ Ret();
 }
 
 
 // Handle the case where the lhs and rhs are the same object.
 // Equality is almost reflexive (everything but NaN), so this is a test
 // for "identity and not NaN".
-static void EmitIdenticalObjectComparison(MacroAssembler* masm,
-                                          Label* slow,
-                                          Condition cc) {
+static void EmitIdenticalObjectComparison(MacroAssembler* masm, Label* slow,
+                                          Condition cc, bool strong) {
   Label not_identical;
   Label heap_number, return_equal;
   Register exp_mask_reg = t5;
 
   __ Branch(&not_identical, ne, a0, Operand(a1));
 
   __ li(exp_mask_reg, Operand(HeapNumber::kExponentMask));
 
   // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
   // so we do the second best thing - test it ourselves.
   // They are both equal and they are not both Smis so both of them are not
   // Smis. If it's not a heap number, then return equal.
   __ GetObjectType(a0, t4, t4);
   if (cc == less || cc == greater) {
+    // Call runtime on identical JSObjects.
     __ Branch(slow, greater, t4, Operand(FIRST_SPEC_OBJECT_TYPE));
+    // Call runtime on identical symbols since we need to throw a TypeError.
     __ Branch(slow, eq, t4, Operand(SYMBOL_TYPE));
+    if (strong) {
+      // Call the runtime on anything that is converted in the semantics, since
+      // we need to throw a TypeError. Smis have already been ruled out.
+      __ Branch(&return_equal, eq, t4, Operand(HEAP_NUMBER_TYPE));
+      __ And(t4, t4, Operand(kIsNotStringMask));
+      __ Branch(slow, ne, t4, Operand(zero_reg));
+    }
   } else {
     __ Branch(&heap_number, eq, t4, Operand(HEAP_NUMBER_TYPE));
     // Comparing JS objects with <=, >= is complicated.
     if (cc != eq) {
     __ Branch(slow, greater, t4, Operand(FIRST_SPEC_OBJECT_TYPE));
+    // Call runtime on identical symbols since we need to throw a TypeError.
     __ Branch(slow, eq, t4, Operand(SYMBOL_TYPE));
+    if (strong) {
+      // Call the runtime on anything that is converted in the semantics,
+      // since we need to throw a TypeError. Smis and heap numbers have
+      // already been ruled out.
+      __ And(t4, t4, Operand(kIsNotStringMask));
+      __ Branch(slow, ne, t4, Operand(zero_reg));
+    }
       // Normally here we fall through to return_equal, but undefined is
       // special: (undefined == undefined) == true, but
       // (undefined <= undefined) == false!  See ECMAScript 11.8.5.
       if (cc == less_equal || cc == greater_equal) {
         __ Branch(&return_equal, ne, t4, Operand(ODDBALL_TYPE));
         __ LoadRoot(t2, Heap::kUndefinedValueRootIndex);
         __ Branch(&return_equal, ne, a0, Operand(t2));
         DCHECK(is_int16(GREATER) && is_int16(LESS));
         __ Ret(USE_DELAY_SLOT);
         if (cc == le) {
@@ skipping 264 matching lines @@
   __ sra(a0, a0, 1);
   __ Ret(USE_DELAY_SLOT);
   __ subu(v0, a1, a0);
   __ bind(&not_two_smis);
 
   // NOTICE! This code is only reached after a smi-fast-case check, so
   // it is certain that at least one operand isn't a smi.
 
   // Handle the case where the objects are identical.  Either returns the answer
   // or goes to slow.  Only falls through if the objects were not identical.
-  EmitIdenticalObjectComparison(masm, &slow, cc);
+  EmitIdenticalObjectComparison(masm, &slow, cc, strong());
 
   // If either is a Smi (we know that not both are), then they can only
   // be strictly equal if the other is a HeapNumber.
   STATIC_ASSERT(kSmiTag == 0);
   DCHECK_EQ(static_cast<Smi*>(0), Smi::FromInt(0));
   __ And(t2, lhs, Operand(rhs));
   __ JumpIfNotSmi(t2, &not_smis, t0);
   // One operand is a smi. EmitSmiNonsmiComparison generates code that can:
   // 1) Return the answer.
   // 2) Go to slow.
@@ skipping 107 matching lines @@
 
   __ bind(&slow);
   // Prepare for call to builtin. Push object pointers, a0 (lhs) first,
   // a1 (rhs) second.
   __ Push(lhs, rhs);
   // Figure out which native to call and setup the arguments.
   Builtins::JavaScript native;
   if (cc == eq) {
     native = strict() ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
   } else {
-    native = Builtins::COMPARE;
+    native = strong() ? Builtins::COMPARE_STRONG : Builtins::COMPARE;
     int ncr;  // NaN compare result.
     if (cc == lt || cc == le) {
       ncr = GREATER;
     } else {
       DCHECK(cc == gt || cc == ge);  // Remaining cases.
       ncr = LESS;
     }
     __ li(a0, Operand(Smi::FromInt(ncr)));
     __ push(a0);
   }
@@ skipping 3009 matching lines @@
   __ bind(&fpu_eq);
   __ Ret(USE_DELAY_SLOT);
   __ li(v0, Operand(EQUAL));
 
   __ bind(&fpu_lt);
   __ Ret(USE_DELAY_SLOT);
   __ li(v0, Operand(LESS));
 
   __ bind(&unordered);
   __ bind(&generic_stub);
-  CompareICStub stub(isolate(), op(), CompareICState::GENERIC,
+  CompareICStub stub(isolate(), op(), strong(), CompareICState::GENERIC,
                      CompareICState::GENERIC, CompareICState::GENERIC);
   __ Jump(stub.GetCode(), RelocInfo::CODE_TARGET);
 
   __ bind(&maybe_undefined1);
   if (Token::IsOrderedRelationalCompareOp(op())) {
     __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
     __ Branch(&miss, ne, a0, Operand(at));
     __ JumpIfSmi(a1, &unordered);
     __ GetObjectType(a1, a2, a2);
     __ Branch(&maybe_undefined2, ne, a2, Operand(HEAP_NUMBER_TYPE));
@@ skipping 1743 matching lines @@
                            kStackUnwindSpace, kInvalidStackOffset,
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS