X87: Correctify instanceof and make it optimizable.

src/x87/code-stubs-x87.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.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2412 matching lines @@
   __ pop(esi);
   __ pop(edi);
   __ add(esp, Immediate(2 * kPointerSize));  // remove markers
 
   // Restore frame pointer and return.
   __ pop(ebp);
   __ ret(0);
 }
 
 
-// Generate stub code for instanceof.
-// This code can patch a call site inlined cache of the instance of check,
-// which looks like this.
-//
-//   81 ff XX XX XX XX   cmp    edi, <the hole, patched to a map>
-//   75 0a               jne    <some near label>
-//   b8 XX XX XX XX      mov    eax, <the hole, patched to either true or false>
-//
-// If call site patching is requested the stack will have the delta from the
-// return address to the cmp instruction just below the return address. This
-// also means that call site patching can only take place with arguments in
-// registers. TOS looks like this when call site patching is requested
-//
-//   esp[0] : return address
-//   esp[4] : delta from return address to cmp instruction
-//
-void InstanceofStub::Generate(MacroAssembler* masm) {
-  // Call site inlining and patching implies arguments in registers.
-  DCHECK(HasArgsInRegisters() || !HasCallSiteInlineCheck());
+void InstanceOfStub::Generate(MacroAssembler* masm) {
+  Register const object = edx;                       // Object (lhs).
+  Register const function = eax;                     // Function (rhs).
+  Register const object_map = ecx;                   // Map of {object}.
+  Register const function_map = ebx;                 // Map of {function}.
+  Register const function_prototype = function_map;  // Prototype of {function}.
+  Register const scratch = edi;
 
-  // Fixed register usage throughout the stub.
-  Register object = eax;  // Object (lhs).
-  Register map = ebx;  // Map of the object.
-  Register function = edx;  // Function (rhs).
-  Register prototype = edi;  // Prototype of the function.
-  Register scratch = ecx;
+  DCHECK(object.is(InstanceOfDescriptor::LeftRegister()));
+  DCHECK(function.is(InstanceOfDescriptor::RightRegister()));
 
-  // Constants describing the call site code to patch.
-  static const int kDeltaToCmpImmediate = 2;
-  static const int kDeltaToMov = 8;
-  static const int kDeltaToMovImmediate = 9;
-  static const int8_t kCmpEdiOperandByte1 = bit_cast<int8_t, uint8_t>(0x3b);
-  static const int8_t kCmpEdiOperandByte2 = bit_cast<int8_t, uint8_t>(0x3d);
-  static const int8_t kMovEaxImmediateByte = bit_cast<int8_t, uint8_t>(0xb8);
+  // Check if {object} is a smi.
+  Label object_is_smi;
+  __ JumpIfSmi(object, &object_is_smi, Label::kNear);
 
-  DCHECK_EQ(object.code(), InstanceofStub::left().code());
-  DCHECK_EQ(function.code(), InstanceofStub::right().code());
+  // Lookup the {function} and the {object} map in the global instanceof cache.
+  // Note: This is safe because we clear the global instanceof cache whenever
+  // we change the prototype of any object.
+  Label fast_case, slow_case;
+  __ mov(object_map, FieldOperand(object, HeapObject::kMapOffset));
+  __ CompareRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
+  __ j(not_equal, &fast_case, Label::kNear);
+  __ CompareRoot(object_map, scratch, Heap::kInstanceofCacheMapRootIndex);
+  __ j(not_equal, &fast_case, Label::kNear);
+  __ LoadRoot(eax, Heap::kInstanceofCacheAnswerRootIndex);
+  __ ret(0);
 
-  // Get the object and function - they are always both needed.
-  Label slow, not_js_object;
-  if (!HasArgsInRegisters()) {
-    __ mov(object, Operand(esp, 2 * kPointerSize));
-    __ mov(function, Operand(esp, 1 * kPointerSize));
-  }
+  // If {object} is a smi we can safely return false if {function} is a JS
+  // function, otherwise we have to miss to the runtime and throw an exception.
+  __ bind(&object_is_smi);
+  __ JumpIfSmi(function, &slow_case);
+  __ CmpObjectType(function, JS_FUNCTION_TYPE, function_map);
+  __ j(not_equal, &slow_case);
+  __ LoadRoot(eax, Heap::kFalseValueRootIndex);
+  __ ret(0);
 
-  // Check that the left hand is a JS object.
-  __ JumpIfSmi(object, &not_js_object);
-  __ IsObjectJSObjectType(object, map, scratch, &not_js_object);
+  // Fast-case: The {function} must be a valid JSFunction.
+  __ bind(&fast_case);
+  __ JumpIfSmi(function, &slow_case);
+  __ CmpObjectType(function, JS_FUNCTION_TYPE, function_map);
+  __ j(not_equal, &slow_case);
 
-  // If there is a call site cache don't look in the global cache, but do the
-  // real lookup and update the call site cache.
-  if (!HasCallSiteInlineCheck() && !ReturnTrueFalseObject()) {
-    // Look up the function and the map in the instanceof cache.
-    Label miss;
-    __ CompareRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
-    __ j(not_equal, &miss, Label::kNear);
-    __ CompareRoot(map, scratch, Heap::kInstanceofCacheMapRootIndex);
-    __ j(not_equal, &miss, Label::kNear);
-    __ LoadRoot(eax, Heap::kInstanceofCacheAnswerRootIndex);
-    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-    __ bind(&miss);
-  }
+  // Ensure that {function} has an instance prototype.
+  __ test_b(FieldOperand(function_map, Map::kBitFieldOffset),
+            static_cast<uint8_t>(1 << Map::kHasNonInstancePrototype));
+  __ j(not_zero, &slow_case);
 
-  // Get the prototype of the function.
-  __ TryGetFunctionPrototype(function, prototype, scratch, &slow, true);
+  // Ensure that {function} is not bound.
+  Register const shared_info = scratch;
+  __ mov(shared_info,
+         FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
+  __ BooleanBitTest(shared_info, SharedFunctionInfo::kCompilerHintsOffset,
+                    SharedFunctionInfo::kBoundFunction);
+  __ j(not_zero, &slow_case);
 
-  // Check that the function prototype is a JS object.
-  __ JumpIfSmi(prototype, &slow);
-  __ IsObjectJSObjectType(prototype, scratch, scratch, &slow);
+  // Get the "prototype" (or initial map) of the {function}.
+  __ mov(function_prototype,
+         FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+  __ AssertNotSmi(function_prototype);
 
-  // Update the global instanceof or call site inlined cache with the current
-  // map and function. The cached answer will be set when it is known below.
-  if (!HasCallSiteInlineCheck()) {
-    __ StoreRoot(map, scratch, Heap::kInstanceofCacheMapRootIndex);
-    __ StoreRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
-  } else {
-    // The constants for the code patching are based on no push instructions
-    // at the call site.
-    DCHECK(HasArgsInRegisters());
-    // Get return address and delta to inlined map check.
-    __ mov(scratch, Operand(esp, 0 * kPointerSize));
-    __ sub(scratch, Operand(esp, 1 * kPointerSize));
-    if (FLAG_debug_code) {
-      __ cmpb(Operand(scratch, 0), kCmpEdiOperandByte1);
-      __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheCmp1);
-      __ cmpb(Operand(scratch, 1), kCmpEdiOperandByte2);
-      __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheCmp2);
-    }
-    __ mov(scratch, Operand(scratch, kDeltaToCmpImmediate));
-    __ mov(Operand(scratch, 0), map);
-    __ push(map);
-    // Scratch points at the cell payload. Calculate the start of the object.
-    __ sub(scratch, Immediate(Cell::kValueOffset - 1));
-    __ RecordWriteField(scratch, Cell::kValueOffset, map, function,
-                        kDontSaveFPRegs, OMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
-    __ pop(map);
-  }
+  // Resolve the prototype if the {function} has an initial map.  Afterwards the
+  // {function_prototype} will be either the JSReceiver prototype object or the
+  // hole value, which means that no instances of the {function} were created so
+  // far and hence we should return false.
+  Label function_prototype_valid;
+  Register const function_prototype_map = scratch;
+  __ CmpObjectType(function_prototype, MAP_TYPE, function_prototype_map);
+  __ j(not_equal, &function_prototype_valid, Label::kNear);
+  __ mov(function_prototype,
+         FieldOperand(function_prototype, Map::kPrototypeOffset));
+  __ bind(&function_prototype_valid);
+  __ AssertNotSmi(function_prototype);
 
-  // Loop through the prototype chain of the object looking for the function
-  // prototype.
-  __ mov(scratch, FieldOperand(map, Map::kPrototypeOffset));
-  Label loop, is_instance, is_not_instance;
+  // Update the global instanceof cache with the current {object} map and
+  // {function}.  The cached answer will be set when it is known below.
+  __ StoreRoot(function, scratch, Heap::kInstanceofCacheFunctionRootIndex);
+  __ StoreRoot(object_map, scratch, Heap::kInstanceofCacheMapRootIndex);
+
+  // Loop through the prototype chain looking for the {function} prototype.
+  // Assume true, and change to false if not found.
+  Register const object_prototype = object_map;
+  Label done, loop;
+  __ mov(eax, isolate()->factory()->true_value());
   __ bind(&loop);
-  __ cmp(scratch, prototype);
-  __ j(equal, &is_instance, Label::kNear);
-  Factory* factory = isolate()->factory();
-  __ cmp(scratch, Immediate(factory->null_value()));
-  __ j(equal, &is_not_instance, Label::kNear);
-  __ mov(scratch, FieldOperand(scratch, HeapObject::kMapOffset));
-  __ mov(scratch, FieldOperand(scratch, Map::kPrototypeOffset));
-  __ jmp(&loop);
+  __ mov(object_prototype, FieldOperand(object_map, Map::kPrototypeOffset));
+  __ cmp(object_prototype, function_prototype);
+  __ j(equal, &done, Label::kNear);
+  __ cmp(object_prototype, isolate()->factory()->null_value());
+  __ mov(object_map, FieldOperand(object_prototype, HeapObject::kMapOffset));
+  __ j(not_equal, &loop);
+  __ mov(eax, isolate()->factory()->false_value());
+  __ bind(&done);
+  __ StoreRoot(eax, scratch, Heap::kInstanceofCacheAnswerRootIndex);
+  __ ret(0);
 
-  __ bind(&is_instance);
-  if (!HasCallSiteInlineCheck()) {
-    __ mov(eax, Immediate(0));
-    __ StoreRoot(eax, scratch, Heap::kInstanceofCacheAnswerRootIndex);
-    if (ReturnTrueFalseObject()) {
-      __ mov(eax, factory->true_value());
-    }
-  } else {
-    // Get return address and delta to inlined map check.
-    __ mov(eax, factory->true_value());
-    __ mov(scratch, Operand(esp, 0 * kPointerSize));
-    __ sub(scratch, Operand(esp, 1 * kPointerSize));
-    if (FLAG_debug_code) {
-      __ cmpb(Operand(scratch, kDeltaToMov), kMovEaxImmediateByte);
-      __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheMov);
-    }
-    __ mov(Operand(scratch, kDeltaToMovImmediate), eax);
-    if (!ReturnTrueFalseObject()) {
-      __ Move(eax, Immediate(0));
-    }
-  }
-  __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-
-  __ bind(&is_not_instance);
-  if (!HasCallSiteInlineCheck()) {
-    __ mov(eax, Immediate(Smi::FromInt(1)));
-    __ StoreRoot(eax, scratch, Heap::kInstanceofCacheAnswerRootIndex);
-    if (ReturnTrueFalseObject()) {
-      __ mov(eax, factory->false_value());
-    }
-  } else {
-    // Get return address and delta to inlined map check.
-    __ mov(eax, factory->false_value());
-    __ mov(scratch, Operand(esp, 0 * kPointerSize));
-    __ sub(scratch, Operand(esp, 1 * kPointerSize));
-    if (FLAG_debug_code) {
-      __ cmpb(Operand(scratch, kDeltaToMov), kMovEaxImmediateByte);
-      __ Assert(equal, kInstanceofStubUnexpectedCallSiteCacheMov);
-    }
-    __ mov(Operand(scratch, kDeltaToMovImmediate), eax);
-    if (!ReturnTrueFalseObject()) {
-      __ Move(eax, Immediate(Smi::FromInt(1)));
-    }
-  }
-  __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-
-  Label object_not_null, object_not_null_or_smi;
-  __ bind(&not_js_object);
-  // Before null, smi and string value checks, check that the rhs is a function
-  // as for a non-function rhs an exception needs to be thrown.
-  __ JumpIfSmi(function, &slow, Label::kNear);
-  __ CmpObjectType(function, JS_FUNCTION_TYPE, scratch);
-  __ j(not_equal, &slow, Label::kNear);
-
-  // Null is not instance of anything.
-  __ cmp(object, factory->null_value());
-  __ j(not_equal, &object_not_null, Label::kNear);
-  if (ReturnTrueFalseObject()) {
-    __ mov(eax, factory->false_value());
-  } else {
-    __ Move(eax, Immediate(Smi::FromInt(1)));
-  }
-  __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-
-  __ bind(&object_not_null);
-  // Smi values is not instance of anything.
-  __ JumpIfNotSmi(object, &object_not_null_or_smi, Label::kNear);
-  if (ReturnTrueFalseObject()) {
-    __ mov(eax, factory->false_value());
-  } else {
-    __ Move(eax, Immediate(Smi::FromInt(1)));
-  }
-  __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-
-  __ bind(&object_not_null_or_smi);
-  // String values is not instance of anything.
-  Condition is_string = masm->IsObjectStringType(object, scratch, scratch);
-  __ j(NegateCondition(is_string), &slow, Label::kNear);
-  if (ReturnTrueFalseObject()) {
-    __ mov(eax, factory->false_value());
-  } else {
-    __ Move(eax, Immediate(Smi::FromInt(1)));
-  }
-  __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-
-  // Slow-case: Go through the JavaScript implementation.
-  __ bind(&slow);
-  if (!ReturnTrueFalseObject()) {
-    // Tail call the builtin which returns 0 or 1.
-    if (HasArgsInRegisters()) {
-      // Push arguments below return address.
-      __ pop(scratch);
-      __ push(object);
-      __ push(function);
-      __ push(scratch);
-    }
-    __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
-  } else {
-    // Call the builtin and convert 0/1 to true/false.
-    {
-      FrameScope scope(masm, StackFrame::INTERNAL);
-      __ push(object);
-      __ push(function);
-      __ InvokeBuiltin(Builtins::INSTANCE_OF, CALL_FUNCTION);
-    }
-    Label true_value, done;
-    __ test(eax, eax);
-    __ j(zero, &true_value, Label::kNear);
-    __ mov(eax, factory->false_value());
-    __ jmp(&done, Label::kNear);
-    __ bind(&true_value);
-    __ mov(eax, factory->true_value());
-    __ bind(&done);
-    __ ret((HasArgsInRegisters() ? 0 : 2) * kPointerSize);
-  }
+  // Slow-case: Call the runtime function.
+  __ bind(&slow_case);
+  __ pop(scratch);    // Pop return address.
+  __ push(object);    // Push {object}.
+  __ push(function);  // Push {function}.
+  __ push(scratch);   // Push return address.
+  __ TailCallRuntime(Runtime::kInstanceOf, 2, 1);
 }
 
 
 // -------------------------------------------------------------------------
 // StringCharCodeAtGenerator
 
 void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // If the receiver is a smi trigger the non-string case.
   if (check_mode_ == RECEIVER_IS_UNKNOWN) {
     __ JumpIfSmi(object_, receiver_not_string_);
@@ skipping 2668 matching lines @@
                            Operand(ebp, 7 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87