[strong] Disallow implicit conversions for comparison

src/arm/code-stubs-arm.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_ARM
 
 #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 cond);
+static void EmitIdenticalObjectComparison(MacroAssembler* masm, Label* slow,
+                                          Condition cond, bool strong);
 static void EmitSmiNonsmiComparison(MacroAssembler* masm,
                                     Register lhs,
                                     Register rhs,
                                     Label* lhs_not_nan,
                                     Label* slow,
                                     bool strict);
 static void EmitStrictTwoHeapObjectCompare(MacroAssembler* masm,
                                            Register lhs,
                                            Register rhs);
 
@@ skipping 122 matching lines @@
   __ bind(&done);
 
   __ Pop(scratch_high, scratch_low, scratch);
   __ 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 cond) {
+static void EmitIdenticalObjectComparison(MacroAssembler* masm, Label* slow,
+                                          Condition cond, bool strong) {
   Label not_identical;
   Label heap_number, return_equal;
   __ cmp(r0, r1);
   __ b(ne, &not_identical);
 
   // 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.
   if (cond == lt || cond == gt) {
+    // Call runtime on identical JSObjects.
     __ CompareObjectType(r0, r4, r4, FIRST_SPEC_OBJECT_TYPE);
     __ b(ge, slow);
+    // Call runtime on identical symbols since we need to throw a TypeError.
     __ cmp(r4, Operand(SYMBOL_TYPE));
     __ b(eq, slow);
+    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.
+      __ cmp(r4, Operand(HEAP_NUMBER_TYPE));
+      __ b(eq, &return_equal);
+      __ tst(r4, Operand(kIsNotStringMask));
+      __ b(ne, slow);
+    }
   } else {
     __ CompareObjectType(r0, r4, r4, HEAP_NUMBER_TYPE);
     __ b(eq, &heap_number);
     // Comparing JS objects with <=, >= is complicated.
     if (cond != eq) {
       __ cmp(r4, Operand(FIRST_SPEC_OBJECT_TYPE));
       __ b(ge, slow);
+      // Call runtime on identical symbols since we need to throw a TypeError.
       __ cmp(r4, Operand(SYMBOL_TYPE));
       __ b(eq, slow);
+      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.
+        __ tst(r4, Operand(kIsNotStringMask));
+        __ b(ne, slow);
+      }
       // 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 (cond == le || cond == ge) {
         __ cmp(r4, Operand(ODDBALL_TYPE));
         __ b(ne, &return_equal);
         __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
         __ cmp(r0, r2);
         __ b(ne, &return_equal);
         if (cond == le) {
@@ skipping 277 matching lines @@
   __ mov(r1, Operand(r1, ASR, 1));
   __ sub(r0, r1, Operand(r0, ASR, 1));
   __ Ret();
   __ 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_(r2, lhs, Operand(rhs));
   __ JumpIfNotSmi(r2, &not_smis);
   // One operand is a smi.  EmitSmiNonsmiComparison generates code that can:
   // 1) Return the answer.
   // 2) Go to slow.
@@ skipping 81 matching lines @@
   // Never falls through to here.
 
   __ bind(&slow);
 
   __ 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;
     }
     __ mov(r0, Operand(Smi::FromInt(ncr)));
     __ push(r0);
   }
@@ skipping 2883 matching lines @@
   __ b(vs, &unordered);
 
   // Return a result of -1, 0, or 1, based on status bits.
   __ mov(r0, Operand(EQUAL), LeaveCC, eq);
   __ mov(r0, Operand(LESS), LeaveCC, lt);
   __ mov(r0, Operand(GREATER), LeaveCC, gt);
   __ Ret();
 
   __ 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())) {
     __ CompareRoot(r0, Heap::kUndefinedValueRootIndex);
     __ b(ne, &miss);
     __ JumpIfSmi(r1, &unordered);
     __ CompareObjectType(r1, r2, r2, HEAP_NUMBER_TYPE);
     __ b(ne, &maybe_undefined2);
@@ skipping 1712 matching lines @@
                            kStackUnwindSpace, NULL,
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM