Bug 1317943 - Fix ThrowReadOnlyError to pass the index instead of the object to the error reporter. r=nbp

js/src/jit-test/tests/ion/bug1317943.js

@@ -0,0 +1,14 @@
+"use strict";
+function test() {
+    for (var i=0; i<10; i++) {
+        try {
+            var arr = [];
+            arr[0] = 1;
+            Object.freeze(arr);
+            arr[0] = 2;
+        } catch (e) {
+            assertEq(e.toString().includes("TypeError: 0 is read-only"), true);
+        }
+    }
+}
+test();

js/src/jit/CodeGenerator.cpp

@@ -8306,7 +8306,7 @@ CodeGenerator::visitStoreElementHoleV(LStoreElementHoleV* lir)
     emitStoreElementHoleV(lir);
 }
 
-typedef bool (*ThrowReadOnlyFn)(JSContext*, HandleObject);
+typedef bool (*ThrowReadOnlyFn)(JSContext*, int32_t);
 static const VMFunction ThrowReadOnlyInfo =
     FunctionInfo<ThrowReadOnlyFn>(ThrowReadOnlyError, "ThrowReadOnlyError");
 
@@ -8321,9 +8321,12 @@ CodeGenerator::visitFallibleStoreElementT(LFallibleStoreElementT* lir)
     if (!lir->mir()->strict()) {
         masm.branchTest32(Assembler::NonZero, flags, Imm32(ObjectElements::FROZEN), &isFrozen);
     } else {
-        Register object = ToRegister(lir->object());
-        OutOfLineCode* ool = oolCallVM(ThrowReadOnlyInfo, lir,
-                ArgList(object), StoreNothing());
+        const LAllocation* index = lir->index();
+        OutOfLineCode* ool;
+        if (index->isConstant())
+            ool = oolCallVM(ThrowReadOnlyInfo, lir, ArgList(Imm32(ToInt32(index))), StoreNothing());
+        else
+            ool = oolCallVM(ThrowReadOnlyInfo, lir, ArgList(ToRegister(index)), StoreNothing());
         masm.branchTest32(Assembler::NonZero, flags, Imm32(ObjectElements::FROZEN), ool->entry());
         // This OOL code should have thrown an exception, so will never return.
         // So, do not bind ool->rejoin() anywhere, so that it implicitly (and without the cost
@@ -8346,9 +8349,12 @@ CodeGenerator::visitFallibleStoreElementV(LFallibleStoreElementV* lir)
     if (!lir->mir()->strict()) {
         masm.branchTest32(Assembler::NonZero, flags, Imm32(ObjectElements::FROZEN), &isFrozen);
     } else {
-        Register object = ToRegister(lir->object());
-        OutOfLineCode* ool = oolCallVM(ThrowReadOnlyInfo, lir,
-                ArgList(object), StoreNothing());
+        const LAllocation* index = lir->index();
+        OutOfLineCode* ool;
+        if (index->isConstant())
+            ool = oolCallVM(ThrowReadOnlyInfo, lir, ArgList(Imm32(ToInt32(index))), StoreNothing());
+        else
+            ool = oolCallVM(ThrowReadOnlyInfo, lir, ArgList(ToRegister(index)), StoreNothing());
         masm.branchTest32(Assembler::NonZero, flags, Imm32(ObjectElements::FROZEN), ool->entry());
         // This OOL code should have thrown an exception, so will never return.
         // So, do not bind ool->rejoin() anywhere, so that it implicitly (and without the cost

js/src/jit/VMFunctions.cpp

@@ -1316,10 +1316,9 @@ ThrowRuntimeLexicalError(JSContext* cx, unsigned errorNumber)
 }
 
 bool
-ThrowReadOnlyError(JSContext* cx, HandleObject handle)
+ThrowReadOnlyError(JSContext* cx, int32_t index)
 {
-    HandleNativeObject obj = handle.as<NativeObject>();
-    RootedValue val(cx, ObjectValue(*obj));
+    RootedValue val(cx, Int32Value(index));
     ReportValueError(cx, JSMSG_READ_ONLY, JSDVG_IGNORE_STACK, val, nullptr);
     return false;
 }

js/src/jit/VMFunctions.h

@@ -786,10 +786,13 @@ bool ObjectIsConstructor(JSObject* obj);
 
 MOZ_MUST_USE bool
 ThrowRuntimeLexicalError(JSContext* cx, unsigned errorNumber);
+
 MOZ_MUST_USE bool
-ThrowReadOnlyError(JSContext* cx, HandleObject obj);
+ThrowReadOnlyError(JSContext* cx, int32_t index);
+
 MOZ_MUST_USE bool
 BaselineThrowUninitializedThis(JSContext* cx, BaselineFrame* frame);
+
 MOZ_MUST_USE bool
 ThrowBadDerivedReturn(JSContext* cx, HandleValue v);