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Unified Diff: src/mips/code-stubs-mips.cc

Issue 1683643002: Mark null and undefined as undetectable, and use it to handle abstract equality comparison in the g… (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Created 4 years, 10 months ago
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Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index b66dbbc96b7513c9fdc75482f889b35fff5c517a..cb269db4c51e81aca42ea519b10196e2da79504e 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -514,45 +514,55 @@ static void EmitCheckForTwoHeapNumbers(MacroAssembler* masm,
// Fast negative check for internalized-to-internalized equality.
static void EmitCheckForInternalizedStringsOrObjects(MacroAssembler* masm,
- Register lhs,
- Register rhs,
+ Register lhs, Register rhs,
Label* possible_strings,
- Label* not_both_strings) {
+ Label* runtime_call) {
DCHECK((lhs.is(a0) && rhs.is(a1)) ||
(lhs.is(a1) && rhs.is(a0)));
// a2 is object type of rhs.
- Label object_test;
+ Label object_test, return_unequal, undetectable;
STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
__ And(at, a2, Operand(kIsNotStringMask));
__ Branch(&object_test, ne, at, Operand(zero_reg));
__ And(at, a2, Operand(kIsNotInternalizedMask));
__ Branch(possible_strings, ne, at, Operand(zero_reg));
__ GetObjectType(rhs, a3, a3);
- __ Branch(not_both_strings, ge, a3, Operand(FIRST_NONSTRING_TYPE));
+ __ Branch(runtime_call, ge, a3, Operand(FIRST_NONSTRING_TYPE));
__ And(at, a3, Operand(kIsNotInternalizedMask));
__ Branch(possible_strings, ne, at, Operand(zero_reg));
- // Both are internalized strings. We already checked they weren't the same
- // pointer so they are not equal.
+ // Both are internalized. We already checked they weren't the same pointer so
+ // they are not equal. Return non-equal by returning the non-zero object
+ // pointer in v0.
__ Ret(USE_DELAY_SLOT);
- __ li(v0, Operand(1)); // Non-zero indicates not equal.
+ __ mov(v0, a0); // In delay slot.
__ bind(&object_test);
- __ Branch(not_both_strings, lt, a2, Operand(FIRST_JS_RECEIVER_TYPE));
- __ GetObjectType(rhs, a2, a3);
- __ Branch(not_both_strings, lt, a3, Operand(FIRST_JS_RECEIVER_TYPE));
-
- // If both objects are undetectable, they are equal. Otherwise, they
- // are not equal, since they are different objects and an object is not
- // equal to undefined.
- __ lw(a3, FieldMemOperand(lhs, HeapObject::kMapOffset));
- __ lbu(a2, FieldMemOperand(a2, Map::kBitFieldOffset));
- __ lbu(a3, FieldMemOperand(a3, Map::kBitFieldOffset));
- __ and_(a0, a2, a3);
- __ And(a0, a0, Operand(1 << Map::kIsUndetectable));
+ __ lw(a2, FieldMemOperand(lhs, HeapObject::kMapOffset));
+ __ lw(a3, FieldMemOperand(rhs, HeapObject::kMapOffset));
+ __ lbu(t0, FieldMemOperand(a2, Map::kBitFieldOffset));
+ __ lbu(t1, FieldMemOperand(a3, Map::kBitFieldOffset));
+ __ And(at, t0, Operand(1 << Map::kIsUndetectable));
+ __ Branch(&undetectable, ne, at, Operand(zero_reg));
+ __ And(at, t1, Operand(1 << Map::kIsUndetectable));
+ __ Branch(&return_unequal, ne, at, Operand(zero_reg));
+
+ __ GetInstanceType(a2, a2);
+ __ Branch(runtime_call, lt, a2, Operand(FIRST_JS_RECEIVER_TYPE));
+ __ GetInstanceType(a3, a3);
+ __ Branch(runtime_call, lt, a3, Operand(FIRST_JS_RECEIVER_TYPE));
+
+ __ bind(&return_unequal);
+ // Return non-equal by returning the non-zero object pointer in v0.
__ Ret(USE_DELAY_SLOT);
- __ xori(v0, a0, 1 << Map::kIsUndetectable);
+ __ mov(v0, a0); // In delay slot.
+
+ __ bind(&undetectable);
+ __ And(at, t1, Operand(1 << Map::kIsUndetectable));
+ __ Branch(&return_unequal, eq, at, Operand(zero_reg));
+ __ Ret(USE_DELAY_SLOT);
+ __ li(v0, Operand(EQUAL)); // In delay slot.
}
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