gecko-dev/js/js2/interpreter.cpp
2000-04-26 05:56:20 +00:00

434 lines
15 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the JavaScript 2 Prototype.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU Public License (the "GPL"), in which case the
* provisions of the GPL are applicable instead of those above.
* If you wish to allow use of your version of this file only
* under the terms of the GPL and not to allow others to use your
* version of this file under the NPL, indicate your decision by
* deleting the provisions above and replace them with the notice
* and other provisions required by the GPL. If you do not delete
* the provisions above, a recipient may use your version of this
* file under either the NPL or the GPL.
*/
#include "interpreter.h"
#include "world.h"
#include "vmtypes.h"
namespace JavaScript {
namespace Interpreter {
// operand access macros.
#define op1(i) (i->o1())
#define op2(i) (i->o2())
#define op3(i) (i->o3())
// mnemonic names for operands.
#define dst(i) op1(i)
#define src1(i) op2(i)
#define src2(i) op3(i)
#define ofs(i) (i->getOffset())
using namespace ICG;
using namespace JSTypes;
// These classes are private to the JS interpreter.
/**
* Represents the current function's invocation state.
*/
struct Activation : public gc_base {
JSValues mRegisters;
ICodeModule* mICode;
Activation(ICodeModule* iCode, const JSValues& args)
: mRegisters(iCode->itsMaxRegister + 1), mICode(iCode)
{
// copy arg list to initial registers.
JSValues::iterator dest = mRegisters.begin();
for (JSValues::const_iterator src = args.begin(),
end = args.end(); src != end; ++src, ++dest) {
*dest = *src;
}
}
Activation(ICodeModule* iCode, Activation* caller,
const RegisterList& list)
: mRegisters(iCode->itsMaxRegister + 1), mICode(iCode)
{
// copy caller's parameter list to initial registers.
JSValues::iterator dest = mRegisters.begin();
const JSValues& params = caller->mRegisters;
for (RegisterList::const_iterator src = list.begin(),
end = list.end(); src != end; ++src, ++dest) {
*dest = params[*src];
}
}
};
/**
* Stores saved state from the *previous* activation, the current
* activation is alive and well in locals of the interpreter loop.
*/
struct Linkage : public gc_base, public Context::Frame {
Linkage* mNext; // next linkage in linkage stack.
InstructionIterator mReturnPC;
InstructionIterator mBasePC;
Activation* mActivation; // caller's activation.
Register mResult; // the desired target register for the return value
Linkage(Linkage* linkage, InstructionIterator returnPC, InstructionIterator basePC,
Activation* activation, Register result)
: mNext(linkage), mReturnPC(returnPC), mBasePC(basePC),
mActivation(activation), mResult(result)
{
}
Context::Frame* getNext() { return mNext; }
void getState(InstructionIterator& pc, JSValues*& registers, ICodeModule*& iCode)
{
pc = mReturnPC;
registers = &mActivation->mRegisters;
iCode = mActivation->mICode;
}
};
JSValue Context::interpret(ICodeModule* iCode, const JSValues& args)
{
// initial activation.
Activation* activation = new Activation(iCode, args);
JSValues* registers = &activation->mRegisters;
InstructionIterator begin_pc = iCode->its_iCode->begin();
InstructionIterator pc = begin_pc;
std::vector<InstructionIterator> catchStack; // <-- later will need to restore scope, other 'global' values
while (true) {
try {
// tell any listeners about the current execution state.
// XXX should only do this if we're single stepping/tracing.
if (mListeners.size()) {
broadcast(pc, registers, activation->mICode);
}
Instruction* instruction = *pc;
switch (instruction->op()) {
case CALL:
{
Call* call = static_cast<Call*>(instruction);
mLinkage = new Linkage(mLinkage, ++pc, begin_pc, activation,
op1(call));
ICodeModule* target =
(*registers)[op2(call)].function->getICode();
activation = new Activation(target, activation, op3(call));
registers = &activation->mRegisters;
begin_pc = pc = target->its_iCode->begin();
}
continue;
case RETURN_VOID:
{
JSValue result(NotARegister);
Linkage *linkage = mLinkage;
if (!linkage)
return result;
mLinkage = linkage->mNext;
activation = linkage->mActivation;
registers = &activation->mRegisters;
(*registers)[linkage->mResult] = result;
pc = linkage->mReturnPC;
begin_pc = linkage->mBasePC;
}
continue;
case RETURN:
{
Return* ret = static_cast<Return*>(instruction);
JSValue result(NotARegister);
if (op1(ret) != NotARegister)
result = (*registers)[op1(ret)];
Linkage* linkage = mLinkage;
if (!linkage)
return result;
mLinkage = linkage->mNext;
activation = linkage->mActivation;
registers = &activation->mRegisters;
(*registers)[linkage->mResult] = result;
pc = linkage->mReturnPC;
begin_pc = linkage->mBasePC;
}
continue;
case MOVE:
{
Move* mov = static_cast<Move*>(instruction);
(*registers)[dst(mov)] = (*registers)[src1(mov)];
}
break;
case LOAD_NAME:
{
LoadName* ln = static_cast<LoadName*>(instruction);
(*registers)[dst(ln)] = (*mGlobal)[*src1(ln)];
}
break;
case SAVE_NAME:
{
SaveName* sn = static_cast<SaveName*>(instruction);
(*mGlobal)[*dst(sn)] = (*registers)[src1(sn)];
}
break;
case NEW_OBJECT:
{
NewObject* no = static_cast<NewObject*>(instruction);
(*registers)[dst(no)].object = new JSObject();
}
break;
case NEW_ARRAY:
{
NewArray* na = static_cast<NewArray*>(instruction);
(*registers)[dst(na)].array = new JSArray();
}
break;
case GET_PROP:
{
GetProp* gp = static_cast<GetProp*>(instruction);
JSObject* object = (*registers)[src1(gp)].object;
(*registers)[dst(gp)] = (*object)[*src2(gp)];
}
break;
case SET_PROP:
{
SetProp* sp = static_cast<SetProp*>(instruction);
JSObject* object = (*registers)[dst(sp)].object;
(*object)[*src1(sp)] = (*registers)[src2(sp)];
}
break;
case GET_ELEMENT:
{
GetElement* ge = static_cast<GetElement*>(instruction);
JSArray* array = (*registers)[src1(ge)].array;
(*registers)[dst(ge)] = (*array)[(*registers)[src2(ge)]];
}
break;
case SET_ELEMENT:
{
SetElement* se = static_cast<SetElement*>(instruction);
JSArray* array = (*registers)[dst(se)].array;
(*array)[(*registers)[src1(se)]] = (*registers)[src2(se)];
}
break;
case LOAD_IMMEDIATE:
{
LoadImmediate* li = static_cast<LoadImmediate*>(instruction);
(*registers)[dst(li)] = JSValue(src1(li));
}
break;
case BRANCH:
{
GenericBranch* bra =
static_cast<GenericBranch*>(instruction);
pc = begin_pc + ofs(bra);
continue;
}
break;
case BRANCH_LT:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 < 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case BRANCH_LE:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 <= 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case BRANCH_EQ:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 == 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case BRANCH_NE:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 != 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case BRANCH_GE:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 >= 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case BRANCH_GT:
{
GenericBranch* bc =
static_cast<GenericBranch*>(instruction);
if ((*registers)[src1(bc)].i32 > 0) {
pc = begin_pc + ofs(bc);
continue;
}
}
break;
case ADD:
{
// could get clever here with Functional forms.
Arithmetic* add = static_cast<Arithmetic*>(instruction);
(*registers)[dst(add)] =
JSValue((*registers)[src1(add)].f64 +
(*registers)[src2(add)].f64);
}
break;
case SUBTRACT:
{
Arithmetic* sub = static_cast<Arithmetic*>(instruction);
(*registers)[dst(sub)] =
JSValue((*registers)[src1(sub)].f64 -
(*registers)[src2(sub)].f64);
}
break;
case MULTIPLY:
{
Arithmetic* mul = static_cast<Arithmetic*>(instruction);
(*registers)[dst(mul)] =
JSValue((*registers)[src1(mul)].f64 *
(*registers)[src2(mul)].f64);
}
break;
case DIVIDE:
{
Arithmetic* div = static_cast<Arithmetic*>(instruction);
(*registers)[dst(div)] =
JSValue((*registers)[src1(div)].f64 /
(*registers)[src2(div)].f64);
}
break;
case COMPARE_LT:
case COMPARE_LE:
case COMPARE_EQ:
case COMPARE_NE:
case COMPARE_GT:
case COMPARE_GE:
{
Arithmetic* cmp = static_cast<Arithmetic*>(instruction);
float64 diff =
((*registers)[src1(cmp)].f64 -
(*registers)[src2(cmp)].f64);
(*registers)[dst(cmp)].i32 =
(diff == 0.0 ? 0 : (diff > 0.0 ? 1 : -1));
}
break;
case NOT:
{
Not* nt = static_cast<Not*>(instruction);
(*registers)[dst(nt)].i32 = !(*registers)[src1(nt)].i32;
}
break;
case THROW :
{
throw new JS_Exception();
}
case TRY:
{ // push the catch handler address onto the try stack
// why did Rhino interpreter also have a finally stack?
Try* tri = static_cast<Try*>(instruction);
catchStack.push_back(begin_pc + ofs(tri));
}
break;
case ENDTRY :
{
catchStack.pop_back();
}
break;
default:
NOT_REACHED("bad opcode");
break;
}
// increment the program counter.
++pc;
}
catch (JS_Exception ) {
ASSERT(!catchStack.empty());
pc = catchStack.back();
catchStack.pop_back();
}
}
} /* interpret */
void Context::addListener(Listener* listener)
{
mListeners.push_back(listener);
}
typedef std::vector<Context::Listener*>::iterator ListenerIterator;
void Context::removeListener(Listener* listener)
{
for (ListenerIterator i = mListeners.begin(), e = mListeners.end(); i != e; ++i) {
if (*i == listener) {
mListeners.erase(i);
break;
}
}
}
void Context::broadcast(InstructionIterator pc, JSValues* registers, ICodeModule* iCode)
{
for (ListenerIterator i = mListeners.begin(), e = mListeners.end(); i != e; ++i) {
Listener* listener = *i;
listener->listen(this, pc, registers, iCode);
}
}
Context::Frame* Context::getFrames()
{
return mLinkage;
}
} /* namespace Interpreter */
} /* namespace JavaScript */