internal override void Generate(CodeGenContext context, CodeEmitter ilgen)
{
ilgen.BeginExceptionBlock();
@try.Generate(context, ilgen);
if (@catch != null)
{
Type type;
if (@catch.type != null)
{
type = StaticCompiler.GetTypeForMapXml(context.ClassLoader, @catch.type);
}
else
{
type = context.ClassLoader.LoadClassByDottedName(@catch.Class).TypeAsExceptionType;
}
ilgen.BeginCatchBlock(type);
@catch.Generate(context, ilgen);
}
if (@finally != null)
{
ilgen.BeginFinallyBlock();
@finally.Generate(context, ilgen);
}
ilgen.EndExceptionBlock();
}
/**
* Emit bytecode for the guardWithCatch idiom.
*
* The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
* <blockquote><pre>{@code
* guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
* t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
* t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
* t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
* }</pre></blockquote>
*
* It is compiled into bytecode equivalent of the following code:
* <blockquote><pre>{@code
* try {
* return a1.invokeBasic(a6, a7);
* } catch (Throwable e) {
* if (!a2.isInstance(e)) throw e;
* return a3.invokeBasic(ex, a6, a7);
* }}</pre></blockquote>
*/
private Name emitGuardWithCatch(int pos)
{
Name args = lambdaForm.names[pos];
Name invoker = lambdaForm.names[pos + 1];
Name result = lambdaForm.names[pos + 2];
CodeEmitterLabel L_handler = ilgen.DefineLabel();
CodeEmitterLabel L_done = ilgen.DefineLabel();
Class returnType = result.function._resolvedHandle().type().returnType();
MethodType type = args.function._resolvedHandle().type()
.dropParameterTypes(0, 1)
.changeReturnType(returnType);
// Normal case
ilgen.BeginExceptionBlock();
// load target
emitPushArgument(invoker, 0);
emitPushArguments(args, 1); // skip 1st argument: method handle
EmitInvokeBasic(type.basicType());
CodeEmitterLocal returnValue = null;
if (returnType != java.lang.Void.TYPE)
{
returnValue = ilgen.DeclareLocal(TypeWrapper.FromClass(returnType).TypeAsLocalOrStackType);
ilgen.Emit(OpCodes.Stloc, returnValue);
}
ilgen.EmitLeave(L_done);
// Exceptional case
ilgen.BeginCatchBlock(typeof(Exception));
// [IKVM] map the exception and store it in a local and exit the handler
ilgen.EmitLdc_I4(0);
ilgen.Emit(OpCodes.Call, ByteCodeHelperMethods.mapException.MakeGenericMethod(typeof(Exception)));
CodeEmitterLocal exception = ilgen.DeclareLocal(typeof(Exception));
ilgen.Emit(OpCodes.Stloc, exception);
ilgen.EmitLeave(L_handler);
ilgen.EndExceptionBlock();
// Check exception's type
ilgen.MarkLabel(L_handler);
// load exception class
emitPushArgument(invoker, 1);
ilgen.Emit(OpCodes.Ldloc, exception);
CoreClasses.java.lang.Class.Wrapper.GetMethodWrapper("isInstance", "(Ljava.lang.Object;)Z", false).EmitCall(ilgen);
CodeEmitterLabel L_rethrow = ilgen.DefineLabel();
ilgen.EmitBrfalse(L_rethrow);
// Invoke catcher
// load catcher
emitPushArgument(invoker, 2);
ilgen.Emit(OpCodes.Ldloc, exception);
emitPushArguments(args, 1); // skip 1st argument: method handle
MethodType catcherType = type.insertParameterTypes(0, CoreClasses.java.lang.Throwable.Wrapper.ClassObject);
EmitInvokeBasic(catcherType.basicType());
if (returnValue != null)
{
ilgen.Emit(OpCodes.Stloc, returnValue);
}
ilgen.EmitBr(L_done);
ilgen.MarkLabel(L_rethrow);
ilgen.Emit(OpCodes.Ldloc, exception);
ilgen.Emit(OpCodes.Call, Compiler.unmapExceptionMethod);
ilgen.Emit(OpCodes.Throw);
ilgen.MarkLabel(L_done);
if (returnValue != null)
{
ilgen.Emit(OpCodes.Ldloc, returnValue);
}
return(result);
}
