Exemplo n.º 1
0
        /// <summary>Pops a labelled block from the stack.</summary>
        public LabelledBlock PopBlock()
        {
            // Pop it:
            LabelledBlock block            = BlockStack.Pop();
            Instruction   blockInstruction = block.Instruction;

            // Transfer all instructions on the FunctionBody.Root stack
            // into blockInstruction up to but not
            // including a match on blockInstruction.

            CompilerStack <Instruction> stack = FunctionBody.Root;

            for (int i = 0; i < stack.Count; i++)
            {
                if (stack.Peek() == blockInstruction)
                {
                    break;
                }

                // Push it into the block:
                blockInstruction.PrependInput(stack.Pop());
            }

            return(block);
        }
Exemplo n.º 2
0
        public FunctionBody(Reader reader, int index)
        {
            // Apply current body:
            reader.FunctionBody = this;

            // Clear the block stack:
            reader.BlockStack.Count = 0;

            // Get the sig:
            Signature = reader.Module.FunctionSection.Types[index];

            // Sizes:
            int bodySize = (int)reader.VarUInt32();

            // Max (bodySize includes locals); -1 to exclude the final byte:
            long max = reader.Position + bodySize - 1;

            // Locals:
            int localCount = (int)reader.VarUInt32();

            List <FunctionLocal> ilLocal = new List <FunctionLocal>(localCount);

            Locals = ilLocal;

            for (int i = 0; i < localCount; i++)
            {
                // # of this and its type:
                int  count = (int)reader.VarUInt32();
                Type type  = reader.ValueTypeConverted();

                for (int c = 0; c < count; c++)
                {
                    // Define it:
                    ilLocal.Add(new FunctionLocal(type));
                }
            }

            // Create the root block instruction (no opcode):
            Root = new CompilerStack <Instruction>();

            // While there is more code..
            while (reader.Position < max)
            {
                // Opcode:
                OpCode opcode = OpCodes.Get(reader.ReadByte());

                if (opcode == null || opcode.OnOutputIL == null)
                {
                    throw new Exception("WebAssembly function body went out of alignment (Function " + Signature.Index + ")");
                }

                if (opcode.Ignored)
                {
                    // Don't create - just load immediates:
                    if (opcode.HasImmediates)
                    {
                        opcode.ReadImmediates(reader);
                    }
                }
                else
                {
                    // Create an instruction:
                    Instruction instruction = new Instruction();
                    instruction.OpCode = opcode;

                    // Apply default in/out:
                    instruction.InputCount = opcode.InputCount;
                    instruction.ReturnType = opcode.ReturnType;
                    reader.Instruction     = instruction;

                    // Add all of its immediates:
                    if (opcode.HasImmediates)
                    {
                        // Load the immediates now:
                        instruction.Immediates = opcode.ReadImmediates(reader);
                    }

                    // Manage the stack now - if it has a fixed number of inputs
                    // we pop those from the stack and add them to the instruction:
                    for (int i = 0; i < instruction.InputCount; i++)
                    {
                        // Add the input to the front of the input set:
                        instruction.PrependInput(Root.Pop());
                    }

                    if (instruction.ReturnType != typeof(void))
                    {
                        // Push to Root:
                        Root.Push(instruction);
                    }
                }
            }

            if (reader.ReadByte() != 0x0b)
            {
                throw new Exception("A function body did not end correctly.");
            }
        }