InstanceOfStub incorrectly interprets the hole as a prototype.

ripsawridge · Commit bot · commit 2aa070be4fd2 · 2016-03-17T14:32:23.000Z
Repair this to match what the runtime correctly does, by first checking if the function is a constructor before we access the prototype. R=verwaest@chromium.org BUG= Review URL: https://codereview.chromium.org/1810953002 Cr-Commit-Position: refs/heads/master@{#34863}
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
@@ -1371,8 +1371,12 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ CompareObjectType(function, function_map, scratch, JS_FUNCTION_TYPE);
   __ b(ne, &slow_case);
 
-  // Ensure that {function} has an instance prototype.
+  // Go to the runtime if the function is not a constructor.
   __ ldrb(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
+  __ tst(scratch, Operand(1 << Map::kIsConstructor));
+  __ b(eq, &slow_case);
+
+  // Ensure that {function} has an instance prototype.
   __ tst(scratch, Operand(1 << Map::kHasNonInstancePrototype));
   __ b(ne, &slow_case);
 
diff --git a/src/arm64/code-stubs-arm64.cc b/src/arm64/code-stubs-arm64.cc
@@ -1557,8 +1557,11 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ JumpIfNotObjectType(function, function_map, scratch, JS_FUNCTION_TYPE,
                          &slow_case);
 
-  // Ensure that {function} has an instance prototype.
+  // Go to the runtime if the function is not a constructor.
   __ Ldrb(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
+  __ Tbz(scratch, Map::kIsConstructor, &slow_case);
+
+  // Ensure that {function} has an instance prototype.
   __ Tbnz(scratch, Map::kHasNonInstancePrototype, &slow_case);
 
   // Get the "prototype" (or initial map) of the {function}.
diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
@@ -2137,6 +2137,11 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ CmpObjectType(function, JS_FUNCTION_TYPE, function_map);
   __ j(not_equal, &slow_case);
 
+  // Go to the runtime if the function is not a constructor.
+  __ test_b(FieldOperand(function_map, Map::kBitFieldOffset),
+            static_cast<uint8_t>(1 << Map::kIsConstructor));
+  __ j(zero, &slow_case);
+
   // Ensure that {function} has an instance prototype.
   __ test_b(FieldOperand(function_map, Map::kBitFieldOffset),
             static_cast<uint8_t>(1 << Map::kHasNonInstancePrototype));
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
@@ -1503,8 +1503,12 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ GetObjectType(function, function_map, scratch);
   __ Branch(&slow_case, ne, scratch, Operand(JS_FUNCTION_TYPE));
 
-  // Ensure that {function} has an instance prototype.
+  // Go to the runtime if the function is not a constructor.
   __ lbu(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
+  __ And(at, scratch, Operand(1 << Map::kIsConstructor));
+  __ Branch(&slow_case, eq, at, Operand(zero_reg));
+
+  // Ensure that {function} has an instance prototype.
   __ And(at, scratch, Operand(1 << Map::kHasNonInstancePrototype));
   __ Branch(&slow_case, ne, at, Operand(zero_reg));
 
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
@@ -1499,8 +1499,12 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ GetObjectType(function, function_map, scratch);
   __ Branch(&slow_case, ne, scratch, Operand(JS_FUNCTION_TYPE));
 
-  // Ensure that {function} has an instance prototype.
+  // Go to the runtime if the function is not a constructor.
   __ lbu(scratch, FieldMemOperand(function_map, Map::kBitFieldOffset));
+  __ And(at, scratch, Operand(1 << Map::kIsConstructor));
+  __ Branch(&slow_case, eq, at, Operand(zero_reg));
+
+  // Ensure that {function} has an instance prototype.
   __ And(at, scratch, Operand(1 << Map::kHasNonInstancePrototype));
   __ Branch(&slow_case, ne, at, Operand(zero_reg));
 
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
@@ -2092,6 +2092,11 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   __ CmpObjectType(function, JS_FUNCTION_TYPE, function_map);
   __ j(not_equal, &slow_case);
 
+  // Go to the runtime if the function is not a constructor.
+  __ testb(FieldOperand(function_map, Map::kBitFieldOffset),
+           Immediate(1 << Map::kIsConstructor));
+  __ j(zero, &slow_case);
+
   // Ensure that {function} has an instance prototype.
   __ testb(FieldOperand(function_map, Map::kBitFieldOffset),
            Immediate(1 << Map::kHasNonInstancePrototype));
diff --git a/test/mjsunit/regress/regress-crbug-573858.js b/test/mjsunit/regress/regress-crbug-573858.js
@@ -9,7 +9,7 @@ var throw_type_error = Object.getOwnPropertyDescriptor(
 
 function create_initial_map() { this instanceof throw_type_error }
 %OptimizeFunctionOnNextCall(create_initial_map);
-create_initial_map();
+assertThrows(create_initial_map);
 
 function test() { new throw_type_error }
 %OptimizeFunctionOnNextCall(test);
