C# CodeGen.PushExceptionBlock方法代码示例

        private void EmitWithCatchBlock(CodeGen cg, Slot exc, Slot exit)
        {
            cg.BeginCatchBlock(typeof(Exception));
            // Extract state from the carrier exception
            cg.EmitCallerContext();
            cg.EmitCall(typeof(Ops), "ExtractException",
                new Type[] { typeof(Exception), typeof(ICallerContext) });
            cg.Emit(OpCodes.Pop);

            // except body
            cg.PushExceptionBlock(Targets.TargetBlockType.Catch, null, null);
            cg.EmitConstantBoxed(false);
            exc.EmitSet(cg);

            cg.EmitCallerContext();
            exit.EmitGet(cg);
            cg.EmitObjectArray(new Expression[0]);
            cg.EmitCallerContext();
            cg.EmitCall(typeof(Ops), "ExtractSysExcInfo");
            cg.EmitCall(typeof(Ops), "CallWithArgsTupleAndContext", new Type[] { typeof(ICallerContext), typeof(object), typeof(object[]), typeof(object) });

            Label afterRaise = cg.DefineLabel();

            cg.EmitTestTrue();
            cg.Emit(OpCodes.Brtrue, afterRaise);
            cg.EmitCall(typeof(Ops), "Raise", new Type[0]); //, new Type[] { typeof(object), typeof(SymbolId) });
            cg.MarkLabel(afterRaise);
            cg.EmitCallerContext();
            cg.EmitCall(typeof(Ops), "ClearException", new Type[] { typeof(ICallerContext) });
            cg.PopTargets();
        }

        private void EmitSimpleTry(CodeGen cg, TryFlowResult flow)
        {
            //
            // Initialize the flow control flag
            //
            Slot flowControlFlag = null;
            if (flow.Any) {
                Debug.Assert(_finally != null);

                flowControlFlag = cg.GetLocalTmp(typeof(int));
                cg.EmitInt(CodeGen.FinallyExitsNormally);
                flowControlFlag.EmitSet(cg);

                //  If there is a control flow in finally, emit outer:
                //  try {
                //      // try block body and all catch handling
                //  } catch (Exception all) {
                //      saved = all;
                //  } finally {
                //      finally_body
                //      if (saved != null) {
                //          throw saved;
                //      }
                //  }

                if (HaveHandlers()) {
                    cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
                    cg.BeginExceptionBlock();
                }
            }

            //******************************************************************
            // 1. ENTERING TRY
            //******************************************************************

            cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
            cg.BeginExceptionBlock();

            //******************************************************************
            // 2. Emit the try statement body
            //******************************************************************

            _body.Emit(cg);
            //cg.EmitSequencePointNone();

            //******************************************************************
            // 3. Emit the catch blocks
            //******************************************************************

            if (HaveHandlers()) {
                cg.PushExceptionBlock(TargetBlockType.Catch, flowControlFlag);

                foreach (CatchBlock cb in _handlers) {
                    // Begin the strongly typed exception block
                    cg.BeginCatchBlock(cb.Test);

                    // Save the exception (if the catch block asked for it) or pop
                    EmitSaveExceptionOrPop(cg, cb);

                    //
                    // Emit the catch block body
                    //
                    cb.Body.Emit(cg);
                }

                cg.PopTargets(TargetBlockType.Catch);
            }

            //******************************************************************
            // 4. Emit the finally block
            //******************************************************************

            if (_finally != null) {
                Slot rethrow = null;
                if (flow.Any) {
                    // If there is a control flow in finally, end the catch
                    // statement and emit the catch-all and finally clause
                    // with rethrow at the end.

                    if (HaveHandlers()) {
                        cg.EndExceptionBlock();
                        cg.PopTargets(TargetBlockType.Try);
                    }

                    cg.PushExceptionBlock(TargetBlockType.Catch, flowControlFlag);
                    cg.BeginCatchBlock(typeof(Exception));

                    rethrow = cg.GetLocalTmp(typeof(Exception));
                    rethrow.EmitSet(cg);

                    cg.PopTargets(TargetBlockType.Catch);
                }

                cg.PushExceptionBlock(TargetBlockType.Finally, flowControlFlag);
                cg.BeginFinallyBlock();

                //
                // Emit the finally block body
                //
                _finally.Emit(cg);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
                isElseYielded.EmitSet(cg);
            }

            if (elseStmt != null) {
                isElseBlock = cg.GetLocalTmp(typeof(bool));
                cg.EmitInt(0);
                isElseBlock.EmitSet(cg);
            }

            Slot exception = null;
            bool foundLoopControl;
            bool returnInFinally = ControlFlowFinder.FindControlFlow(FinallyStatement, out foundLoopControl);

            if (IsBlockYieldable(finallyYieldTargets)) {
                exception = cg.Names.GetTempSlot("exception", typeof(Exception));
                cg.Emit(OpCodes.Ldnull);
                exception.EmitSet(cg);
            } else if (returnInFinally) {
                exception = cg.GetLocalTmp(typeof(Exception));
                cg.Emit(OpCodes.Ldnull);
                exception.EmitSet(cg);
            }

            EmitTopYieldTargetLabels(tryYieldTargets, tryChoiceVar, cg);
            EmitTopYieldTargetLabels(catchYieldTargets, catchChoiceVar, cg);
            EmitTopYieldTargetLabels(elseYieldTargets, elseChoiceVar, cg);
            EmitTopYieldTargetLabels(finallyYieldTargets, finallyChoiceVar, cg);

            cg.EmitInt(CodeGen.FinallyExitsNormally);
            flowControlVar.EmitSet(cg);

            Label afterFinally = cg.DefineLabel();

            cg.PushExceptionBlock(Targets.TargetBlockType.Try, flowControlVar, isTryYielded);
            cg.BeginExceptionBlock();

            // if catch yielded, rethow the storedException to be handled by Catch block
            if (IsBlockYieldable(catchYieldTargets)) {
                Label testFinally = cg.DefineLabel();
                isCatchYielded.EmitGet(cg);
                cg.EmitUnbox(typeof(bool));
                cg.Emit(OpCodes.Brfalse, testFinally);
                storedException.EmitGet(cg);
                cg.EmitCall(typeof(Ops), "Raise", new Type[] { typeof(object) });
                cg.MarkLabel(testFinally);
            }

            // if Finally yielded, Branch to the end of Try block
            Label endOfTry = cg.DefineLabel();
            EmitOnYieldBranchToLabel(finallyYieldTargets, isFinallyYielded, endOfTry, cg);

            Label beginElseBlock = cg.DefineLabel();
            if (IsBlockYieldable(elseYieldTargets)) {
                // isElseYielded ?
                Debug.Assert(isElseYielded != null);
                isElseYielded.EmitGet(cg);
                cg.EmitUnbox(typeof(bool));
                cg.Emit(OpCodes.Brtrue, beginElseBlock);
            }

            EmitYieldDispatch(tryYieldTargets, isTryYielded, tryChoiceVar, cg);

            // if finally block presents, but no exception handler, we add try-fault
            // to update traceback; otherwise, we update the traceback inside exception handler.
            if (finallyStmt != null && handlers == null) {
                Slot dummySlot = cg.GetLocalTmp(typeof(object));

        private void EmitGeneratorTry(CodeGen cg, TryFlowResult flow)
        {
            //
            // Initialize the flow control flag
            //
            Slot flowControlFlag = null;

            if (flow.Any) {
                flowControlFlag = cg.GetLocalTmp(typeof(int));
                cg.EmitInt(CodeGen.FinallyExitsNormally);
                flowControlFlag.EmitSet(cg);
            }

            Slot exception = null;
            if (_finally != null) {
                exception = cg.GetTemporarySlot(typeof(Exception));
                cg.EmitNull();
                exception.EmitSet(cg);
            }

            //******************************************************************
            // Entering the try block
            //******************************************************************

            if (_target != null) {
                cg.MarkLabel(_target.EnsureLabel(cg));
            }

            //******************************************************************
            // If we have a 'finally', transform it into try..catch..finally
            // and rethrow
            //******************************************************************
            Label endFinallyBlock = new Label();
            if (_finally != null) {
                cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
                cg.BeginExceptionBlock();
                endFinallyBlock = cg.DefineLabel();

                //**************************************************************
                // If there is a yield in any catch, that catch will be hoisted
                // and we need to dispatch to it from here
                //**************************************************************
                if (_yieldInCatch) {
                    EmitYieldDispatch(_catchYields, cg);
                }

                if (YieldInBlock(_finallyYields)) {
                    foreach (YieldTarget yt in _finallyYields) {
                        cg.GotoRouter.EmitGet(cg);
                        cg.EmitInt(yt.Index);
                        cg.Emit(OpCodes.Beq, endFinallyBlock);
                    }
                }
            }

            //******************************************************************
            // If we have a 'catch', start a try block to handle all the catches
            //******************************************************************

            Label endCatchBlock = new Label();
            if (HaveHandlers()) {
                cg.PushExceptionBlock(TargetBlockType.Try, flowControlFlag);
                endCatchBlock = cg.BeginExceptionBlock();
            }

            //******************************************************************
            // Emit the try block body
            //******************************************************************

            // First, emit the dispatch within the try block
            EmitYieldDispatch(_tryYields, cg);

            // Then, emit the actual body
            _body.Emit(cg);
            //cg.EmitSequencePointNone();

            //******************************************************************
            // Emit the catch blocks
            //******************************************************************

            if (HaveHandlers()) {
                List<CatchRecord> catches = new List<CatchRecord>();
                cg.PushExceptionBlock(TargetBlockType.Catch, flowControlFlag);

                foreach (CatchBlock cb in _handlers) {
                    cg.BeginCatchBlock(cb.Test);

                    if (cb.Yield) {
                        // The catch block body contains yield, therefore
                        // delay the body emit till after the try block.
                        Slot slot = cg.GetLocalTmp(cb.Test);
                        slot.EmitSet(cg);
                        catches.Add(new CatchRecord(slot, cb));
                    } else {
                        // Save the exception (if the catch block asked for it) or pop
                        EmitSaveExceptionOrPop(cg, cb);
                        // Emit the body right now, since it doesn't contain yield
                        cb.Body.Emit(cg);
                    }
                }
//.........这里部分代码省略.........