Changeset 60075 in webkit for trunk/JavaScriptCore/interpreter/Interpreter.cpp

Timestamp:

May 24, 2010, 11:46:49 AM (15 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=39583
Move creation of 'this' object from caller to callee in construction.

Reviewed by Sam Weinig.

Presently the caller of a constructor is responsible for providing a this
object. Instead, move the object creation into a new op_create_this opcode,
planted in the head of the contructor bytecode for a function. Since the
prototype for the object is provided by performing a get_by_id on the callee,
also add a new get_callee opcode (this is used to get the callee JSFunction
into a register so that a normal get_by_id can be used).

Currently the caller is also responsible for detecting when op_construct is
performed on a JSFunction representing a host function, in which case an
exception is thrown – and this check currently takes place when constructing
the this object. Instead, mirroring the recent changes for non-host functions,
add a parallel code-path for native constructors to follow, with a thunk for
invoking native constructors provided by JITStubs, and a constructor-specific
NativeFunction on NativeExecutable. Provide an implementation of a host
constructor which will throw an exception.

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::dump):
(JSC::CodeBlock::getByIdExceptionInfoForBytecodeOffset):

• bytecode/CodeBlock.h:
• bytecode/Opcode.h:
• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::emitConstruct):

• bytecompiler/BytecodeGenerator.h:

(JSC::BytecodeGenerator::emitGetByIdExceptionInfo):

• interpreter/Interpreter.cpp:

(JSC::Interpreter::privateExecute):

• jit/JIT.cpp:

(JSC::JIT::privateCompileMainPass):

• jit/JIT.h:
• jit/JITCall.cpp:

(JSC::JIT::compileOpCall):
(JSC::JIT::compileOpCallSlowCase):

• jit/JITCall32_64.cpp:

(JSC::JIT::compileOpCall):
(JSC::JIT::compileOpCallSlowCase):

• jit/JITOpcodes.cpp:

(JSC::JIT::privateCompileCTIMachineTrampolines):
(JSC::JIT::privateCompileCTINativeCall):
(JSC::JIT::emit_op_neq_null):
(JSC::JIT::emit_op_convert_this):
(JSC::JIT::emit_op_get_callee):
(JSC::JIT::emit_op_create_this):

• jit/JITOpcodes32_64.cpp:

(JSC::JIT::privateCompileCTIMachineTrampolines):
(JSC::JIT::privateCompileCTINativeCall):
(JSC::JIT::emit_op_get_callee):
(JSC::JIT::emit_op_create_this):

• jit/JITStubs.cpp:

(JSC::DEFINE_STUB_FUNCTION):
(JSC::JITThunks::hostFunctionStub):

• jit/JITStubs.h:

(JSC::JITThunks::ctiNativeConstruct):
(JSC::):

• runtime/ExceptionHelpers.cpp:

(JSC::createNotAnObjectError):

• runtime/Executable.h:

(JSC::NativeExecutable::create):
(JSC::NativeExecutable::NativeExecutable):

• runtime/JSFunction.cpp:

(JSC::callHostFunctionAsConstructor):

• runtime/JSFunction.h:

File:

• trunk/JavaScriptCore/interpreter/Interpreter.cpp (modified) (6 diffs)

trunk/JavaScriptCore/interpreter/Interpreter.cpp

@@ -3840 +3840 @@
         vPC = callFrame->returnPC();
         callFrame = callFrame->callerFrame();
+        codeBlock = callFrame->codeBlock();
         
         if (callFrame->hasHostCallFrameFlag())
@@ -3884 +3885 @@
         vPC = callFrame->returnPC();
         callFrame = callFrame->callerFrame();
+        codeBlock = callFrame->codeBlock();
         
         if (callFrame->hasHostCallFrameFlag())
@@ -3929 +3931 @@
 
         vPC += OPCODE_LENGTH(op_enter_with_activation);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_get_callee) {
+        /* op_get_callee callee(r)
+
+           Move callee into a register.
+        */
+
+        callFrame->r(vPC[1].u.operand) = callFrame->callee();
+
+        vPC += OPCODE_LENGTH(op_get_callee);
+        NEXT_INSTRUCTION();
+    }
+    DEFINE_OPCODE(op_create_this) {
+        /* op_create_this this(r) proto(r)
+
+           Allocate an object as 'this', fr use in construction.
+
+           This opcode should only be used at the beginning of a code
+           block.
+        */
+
+        int thisRegister = vPC[1].u.operand;
+        int protoRegister = vPC[2].u.operand;
+
+        JSFunction* constructor = asFunction(callFrame->callee());
+#if !ASSERT_DISABLED
+        ConstructData constructData;
+        ASSERT(constructor->getConstructData(constructData) == ConstructTypeJS);
+#endif
+
+        Structure* structure;
+        JSValue proto = callFrame->r(protoRegister).jsValue();
+        if (proto.isObject())
+            structure = asObject(proto)->inheritorID();
+        else
+            structure = constructor->scope().node()->globalObject->emptyObjectStructure();
+        callFrame->r(thisRegister) = new (&callFrame->globalData()) JSObject(structure);
+
+        vPC += OPCODE_LENGTH(op_create_this);
         NEXT_INSTRUCTION();
     }
@@ -4001 +4043 @@
         int argCount = vPC[2].u.operand;
         int registerOffset = vPC[3].u.operand;
-        int proto = vPC[4].u.operand;
-        int thisRegister = vPC[5].u.operand;
 
         JSValue v = callFrame->r(func).jsValue();
@@ -4012 +4052 @@
             ScopeChainNode* callDataScopeChain = constructData.js.scopeChain;
             CodeBlock* newCodeBlock = &constructData.js.functionExecutable->bytecodeForConstruct(callFrame, callDataScopeChain);
-
-            Structure* structure;
-            JSValue prototype = callFrame->r(proto).jsValue();
-            if (prototype.isObject())
-                structure = asObject(prototype)->inheritorID();
-            else
-                structure = callDataScopeChain->globalObject->emptyObjectStructure();
-            JSObject* newObject = new (globalData) JSObject(structure);
-
-            callFrame->r(thisRegister) = JSValue(newObject); // "this" value
 
             CallFrame* previousCallFrame = callFrame;
@@ -4044 +4074 @@
 
         if (constructType == ConstructTypeHost) {
-            ArgList args(callFrame->registers() + thisRegister + 1, argCount - 1);
-
             ScopeChainNode* scopeChain = callFrame->scopeChain();
             CallFrame* newCallFrame = CallFrame::create(callFrame->registers() + registerOffset);
             newCallFrame->init(0, vPC + OPCODE_LENGTH(op_construct), scopeChain, callFrame, 0, argCount, 0);
+
+            Register* thisRegister = newCallFrame->registers() - RegisterFile::CallFrameHeaderSize - argCount;
+            ArgList args(thisRegister + 1, argCount - 1);
 
             JSValue returnValue;