[strong] Disallow implicit conversions for comparison

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index 5b5e050f511f0fc108e4f5993664febef7439e7e..47e8e8d45a92ceca266fdbfec0fbf8915dc8ede3 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -93,9 +93,8 @@ void InternalArrayNArgumentsConstructorStub::InitializeDescriptor(
 #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,
@@ -276,9 +275,8 @@ void DoubleToIStub::Generate(MacroAssembler* masm) {
 // 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;
@@ -293,14 +291,31 @@ static void EmitIdenticalObjectComparison(MacroAssembler* masm,
   // 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.
@@ -585,7 +600,7 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
 
   // 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.
@@ -713,7 +728,7 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
   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;
@@ -3743,7 +3758,7 @@ void CompareICStub::GenerateNumbers(MacroAssembler* masm) {
 
   __ 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);