| public AddTableSwitch ( int low, int high ) : int | ||
| low | int | |
| high | int | |
| Результат | int | |
private void GenerateNativeFunctionOverrides(ClassFileWriter cfw, string encodedSource)
{
// Override NativeFunction.getLanguageVersion() with
// public int getLanguageVersion() { return <version-constant>; }
cfw.StartMethod("getLanguageVersion", "()I", ClassFileWriter.ACC_PUBLIC);
cfw.AddPush(compilerEnv.GetLanguageVersion());
cfw.Add(ByteCode.IRETURN);
// 1: this and no argument or locals
cfw.StopMethod((short)1);
// The rest of NativeFunction overrides require specific code for each
// script/function id
int Do_getFunctionName = 0;
int Do_getParamCount = 1;
int Do_getParamAndVarCount = 2;
int Do_getParamOrVarName = 3;
int Do_getEncodedSource = 4;
int Do_getParamOrVarConst = 5;
int SWITCH_COUNT = 6;
for (int methodIndex = 0; methodIndex != SWITCH_COUNT; ++methodIndex)
{
if (methodIndex == Do_getEncodedSource && encodedSource == null)
{
continue;
}
// Generate:
// prologue;
// switch over function id to implement function-specific action
// epilogue
short methodLocals;
switch (methodIndex)
{
case Do_getFunctionName:
{
methodLocals = 1;
// Only this
cfw.StartMethod("getFunctionName", "()Ljava/lang/String;", ClassFileWriter.ACC_PUBLIC);
break;
}
case Do_getParamCount:
{
methodLocals = 1;
// Only this
cfw.StartMethod("getParamCount", "()I", ClassFileWriter.ACC_PUBLIC);
break;
}
case Do_getParamAndVarCount:
{
methodLocals = 1;
// Only this
cfw.StartMethod("getParamAndVarCount", "()I", ClassFileWriter.ACC_PUBLIC);
break;
}
case Do_getParamOrVarName:
{
methodLocals = 1 + 1;
// this + paramOrVarIndex
cfw.StartMethod("getParamOrVarName", "(I)Ljava/lang/String;", ClassFileWriter.ACC_PUBLIC);
break;
}
case Do_getParamOrVarConst:
{
methodLocals = 1 + 1 + 1;
// this + paramOrVarName
cfw.StartMethod("getParamOrVarConst", "(I)Z", ClassFileWriter.ACC_PUBLIC);
break;
}
case Do_getEncodedSource:
{
methodLocals = 1;
// Only this
cfw.StartMethod("getEncodedSource", "()Ljava/lang/String;", ClassFileWriter.ACC_PUBLIC);
cfw.AddPush(encodedSource);
break;
}
default:
{
throw Kit.CodeBug();
}
}
int count = scriptOrFnNodes.Length;
int switchStart = 0;
int switchStackTop = 0;
if (count > 1)
{
// Generate switch but only if there is more then one
// script/function
cfw.AddLoadThis();
cfw.Add(ByteCode.GETFIELD, cfw.GetClassName(), ID_FIELD_NAME, "I");
// do switch from 1 .. count - 1 mapping 0 to the default case
switchStart = cfw.AddTableSwitch(1, count - 1);
}
for (int i = 0; i != count; ++i)
{
ScriptNode n = scriptOrFnNodes[i];
if (i == 0)
{
if (count > 1)
{
cfw.MarkTableSwitchDefault(switchStart);
switchStackTop = cfw.GetStackTop();
}
}
else
{
cfw.MarkTableSwitchCase(switchStart, i - 1, switchStackTop);
}
switch (methodIndex)
{
case Do_getFunctionName:
{
// Impelemnet method-specific switch code
// Push function name
if (n.GetType() == Token.SCRIPT)
{
cfw.AddPush(string.Empty);
}
else
{
string name = ((FunctionNode)n).GetName();
cfw.AddPush(name);
}
cfw.Add(ByteCode.ARETURN);
break;
}
case Do_getParamCount:
{
// Push number of defined parameters
cfw.AddPush(n.GetParamCount());
cfw.Add(ByteCode.IRETURN);
break;
}
case Do_getParamAndVarCount:
{
// Push number of defined parameters and declared variables
cfw.AddPush(n.GetParamAndVarCount());
cfw.Add(ByteCode.IRETURN);
break;
}
case Do_getParamOrVarName:
{
// Push name of parameter using another switch
// over paramAndVarCount
int paramAndVarCount = n.GetParamAndVarCount();
if (paramAndVarCount == 0)
{
// The runtime should never call the method in this
// case but to make bytecode verifier happy return null
// as throwing execption takes more code
cfw.Add(ByteCode.ACONST_NULL);
cfw.Add(ByteCode.ARETURN);
}
else
{
if (paramAndVarCount == 1)
{
// As above do not check for valid index but always
// return the name of the first param
cfw.AddPush(n.GetParamOrVarName(0));
cfw.Add(ByteCode.ARETURN);
}
else
{
// Do switch over getParamOrVarName
cfw.AddILoad(1);
// param or var index
// do switch from 1 .. paramAndVarCount - 1 mapping 0
// to the default case
int paramSwitchStart = cfw.AddTableSwitch(1, paramAndVarCount - 1);
for (int j = 0; j != paramAndVarCount; ++j)
{
if (cfw.GetStackTop() != 0)
{
Kit.CodeBug();
}
string s = n.GetParamOrVarName(j);
if (j == 0)
{
cfw.MarkTableSwitchDefault(paramSwitchStart);
}
else
{
cfw.MarkTableSwitchCase(paramSwitchStart, j - 1, 0);
}
cfw.AddPush(s);
cfw.Add(ByteCode.ARETURN);
}
}
}
break;
}
case Do_getParamOrVarConst:
{
// Push name of parameter using another switch
// over paramAndVarCount
paramAndVarCount = n.GetParamAndVarCount();
bool[] constness = n.GetParamAndVarConst();
if (paramAndVarCount == 0)
{
// The runtime should never call the method in this
// case but to make bytecode verifier happy return null
// as throwing execption takes more code
cfw.Add(ByteCode.ICONST_0);
cfw.Add(ByteCode.IRETURN);
}
else
{
if (paramAndVarCount == 1)
{
// As above do not check for valid index but always
// return the name of the first param
cfw.AddPush(constness[0]);
cfw.Add(ByteCode.IRETURN);
}
else
{
// Do switch over getParamOrVarName
cfw.AddILoad(1);
// param or var index
// do switch from 1 .. paramAndVarCount - 1 mapping 0
// to the default case
int paramSwitchStart = cfw.AddTableSwitch(1, paramAndVarCount - 1);
for (int j = 0; j != paramAndVarCount; ++j)
{
if (cfw.GetStackTop() != 0)
{
Kit.CodeBug();
}
if (j == 0)
{
cfw.MarkTableSwitchDefault(paramSwitchStart);
}
else
{
cfw.MarkTableSwitchCase(paramSwitchStart, j - 1, 0);
}
cfw.AddPush(constness[j]);
cfw.Add(ByteCode.IRETURN);
}
}
}
break;
}
case Do_getEncodedSource:
{
// Push number encoded source start and end
// to prepare for encodedSource.substring(start, end)
cfw.AddPush(n.GetEncodedSourceStart());
cfw.AddPush(n.GetEncodedSourceEnd());
cfw.AddInvoke(ByteCode.INVOKEVIRTUAL, "java/lang/String", "substring", "(II)Ljava/lang/String;");
cfw.Add(ByteCode.ARETURN);
break;
}
default:
{
throw Kit.CodeBug();
}
}
}
cfw.StopMethod(methodLocals);
}
}
private void GenerateCallMethod(ClassFileWriter cfw)
{
cfw.StartMethod("call", "(Lorg/mozilla/javascript/Context;" + "Lorg/mozilla/javascript/Scriptable;" + "Lorg/mozilla/javascript/Scriptable;" + "[Ljava/lang/Object;)Ljava/lang/Object;", (short)(ClassFileWriter.ACC_PUBLIC | ClassFileWriter.ACC_FINAL));
// Generate code for:
// if (!ScriptRuntime.hasTopCall(cx)) {
// return ScriptRuntime.doTopCall(this, cx, scope, thisObj, args);
// }
int nonTopCallLabel = cfw.AcquireLabel();
cfw.AddALoad(1);
//cx
cfw.AddInvoke(ByteCode.INVOKESTATIC, "org/mozilla/javascript/ScriptRuntime", "hasTopCall", "(Lorg/mozilla/javascript/Context;" + ")Z");
cfw.Add(ByteCode.IFNE, nonTopCallLabel);
cfw.AddALoad(0);
cfw.AddALoad(1);
cfw.AddALoad(2);
cfw.AddALoad(3);
cfw.AddALoad(4);
cfw.AddInvoke(ByteCode.INVOKESTATIC, "org/mozilla/javascript/ScriptRuntime", "doTopCall", "(Lorg/mozilla/javascript/Callable;" + "Lorg/mozilla/javascript/Context;" + "Lorg/mozilla/javascript/Scriptable;" + "Lorg/mozilla/javascript/Scriptable;" + "[Ljava/lang/Object;" + ")Ljava/lang/Object;");
cfw.Add(ByteCode.ARETURN);
cfw.MarkLabel(nonTopCallLabel);
// Now generate switch to call the real methods
cfw.AddALoad(0);
cfw.AddALoad(1);
cfw.AddALoad(2);
cfw.AddALoad(3);
cfw.AddALoad(4);
int end = scriptOrFnNodes.Length;
bool generateSwitch = (2 <= end);
int switchStart = 0;
int switchStackTop = 0;
if (generateSwitch)
{
cfw.AddLoadThis();
cfw.Add(ByteCode.GETFIELD, cfw.GetClassName(), ID_FIELD_NAME, "I");
// do switch from (1, end - 1) mapping 0 to
// the default case
switchStart = cfw.AddTableSwitch(1, end - 1);
}
for (int i = 0; i != end; ++i)
{
ScriptNode n = scriptOrFnNodes[i];
if (generateSwitch)
{
if (i == 0)
{
cfw.MarkTableSwitchDefault(switchStart);
switchStackTop = cfw.GetStackTop();
}
else
{
cfw.MarkTableSwitchCase(switchStart, i - 1, switchStackTop);
}
}
if (n.GetType() == Token.FUNCTION)
{
OptFunctionNode ofn = OptFunctionNode.Get(n);
if (ofn.IsTargetOfDirectCall())
{
int pcount = ofn.fnode.GetParamCount();
if (pcount != 0)
{
// loop invariant:
// stack top == arguments array from addALoad4()
for (int p = 0; p != pcount; ++p)
{
cfw.Add(ByteCode.ARRAYLENGTH);
cfw.AddPush(p);
int undefArg = cfw.AcquireLabel();
int beyond = cfw.AcquireLabel();
cfw.Add(ByteCode.IF_ICMPLE, undefArg);
// get array[p]
cfw.AddALoad(4);
cfw.AddPush(p);
cfw.Add(ByteCode.AALOAD);
cfw.Add(ByteCode.GOTO, beyond);
cfw.MarkLabel(undefArg);
PushUndefined(cfw);
cfw.MarkLabel(beyond);
// Only one push
cfw.AdjustStackTop(-1);
cfw.AddPush(0.0);
// restore invariant
cfw.AddALoad(4);
}
}
}
}
cfw.AddInvoke(ByteCode.INVOKESTATIC, mainClassName, GetBodyMethodName(n), GetBodyMethodSignature(n));
cfw.Add(ByteCode.ARETURN);
}
cfw.StopMethod((short)5);
}
private void GenerateFunctionConstructor(ClassFileWriter cfw)
{
int SCOPE_ARG = 1;
int CONTEXT_ARG = 2;
int ID_ARG = 3;
cfw.StartMethod("<init>", FUNCTION_CONSTRUCTOR_SIGNATURE, ClassFileWriter.ACC_PUBLIC);
cfw.AddALoad(0);
cfw.AddInvoke(ByteCode.INVOKESPECIAL, SUPER_CLASS_NAME, "<init>", "()V");
cfw.AddLoadThis();
cfw.AddILoad(ID_ARG);
cfw.Add(ByteCode.PUTFIELD, cfw.GetClassName(), ID_FIELD_NAME, "I");
cfw.AddLoadThis();
cfw.AddALoad(CONTEXT_ARG);
cfw.AddALoad(SCOPE_ARG);
int start = (scriptOrFnNodes[0].GetType() == Token.SCRIPT) ? 1 : 0;
int end = scriptOrFnNodes.Length;
if (start == end)
{
throw BadTree();
}
bool generateSwitch = (2 <= end - start);
int switchStart = 0;
int switchStackTop = 0;
if (generateSwitch)
{
cfw.AddILoad(ID_ARG);
// do switch from (start + 1, end - 1) mapping start to
// the default case
switchStart = cfw.AddTableSwitch(start + 1, end - 1);
}
for (int i = start; i != end; ++i)
{
if (generateSwitch)
{
if (i == start)
{
cfw.MarkTableSwitchDefault(switchStart);
switchStackTop = cfw.GetStackTop();
}
else
{
cfw.MarkTableSwitchCase(switchStart, i - 1 - start, switchStackTop);
}
}
OptFunctionNode ofn = OptFunctionNode.Get(scriptOrFnNodes[i]);
cfw.AddInvoke(ByteCode.INVOKESPECIAL, mainClassName, GetFunctionInitMethodName(ofn), FUNCTION_INIT_SIGNATURE);
cfw.Add(ByteCode.RETURN);
}
// 4 = this + scope + context + id
cfw.StopMethod((short)4);
}
// How dispatch to generators works:
// Two methods are generated corresponding to a user-written generator.
// One of these creates a generator object (NativeGenerator), which is
// returned to the user. The other method contains all of the body code
// of the generator.
// When a user calls a generator, the call() method dispatches control to
// to the method that creates the NativeGenerator object. Subsequently when
// the user invokes .next(), .send() or any such method on the generator
// object, the resumeGenerator() below dispatches the call to the
// method corresponding to the generator body. As a matter of convention
// the generator body is given the name of the generator activation function
// appended by "_gen".
private void GenerateResumeGenerator(ClassFileWriter cfw)
{
bool hasGenerators = false;
for (int i = 0; i < scriptOrFnNodes.Length; i++)
{
if (IsGenerator(scriptOrFnNodes[i]))
{
hasGenerators = true;
}
}
// if there are no generators defined, we don't implement a
// resumeGenerator(). The base class provides a default implementation.
if (!hasGenerators)
{
return;
}
cfw.StartMethod("resumeGenerator", "(Lorg/mozilla/javascript/Context;" + "Lorg/mozilla/javascript/Scriptable;" + "ILjava/lang/Object;" + "Ljava/lang/Object;)Ljava/lang/Object;", (short)(ClassFileWriter.ACC_PUBLIC | ClassFileWriter.ACC_FINAL));
// load arguments for dispatch to the corresponding *_gen method
cfw.AddALoad(0);
cfw.AddALoad(1);
cfw.AddALoad(2);
cfw.AddALoad(4);
cfw.AddALoad(5);
cfw.AddILoad(3);
cfw.AddLoadThis();
cfw.Add(ByteCode.GETFIELD, cfw.GetClassName(), ID_FIELD_NAME, "I");
int startSwitch = cfw.AddTableSwitch(0, scriptOrFnNodes.Length - 1);
cfw.MarkTableSwitchDefault(startSwitch);
int endlabel = cfw.AcquireLabel();
for (int i_1 = 0; i_1 < scriptOrFnNodes.Length; i_1++)
{
ScriptNode n = scriptOrFnNodes[i_1];
cfw.MarkTableSwitchCase(startSwitch, i_1, (short)6);
if (IsGenerator(n))
{
string type = "(" + mainClassSignature + "Lorg/mozilla/javascript/Context;" + "Lorg/mozilla/javascript/Scriptable;" + "Ljava/lang/Object;" + "Ljava/lang/Object;I)Ljava/lang/Object;";
cfw.AddInvoke(ByteCode.INVOKESTATIC, mainClassName, GetBodyMethodName(n) + "_gen", type);
cfw.Add(ByteCode.ARETURN);
}
else
{
cfw.Add(ByteCode.GOTO, endlabel);
}
}
cfw.MarkLabel(endlabel);
PushUndefined(cfw);
cfw.Add(ByteCode.ARETURN);
// this method uses as many locals as there are arguments (hence 6)
cfw.StopMethod((short)6);
}