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station_obscurum_unity/Assets/FishNet/CodeGenerating/cecil-0.11.4/Mono.Cecil.Cil/CodeWriter.cs

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2023-05-31 17:32:21 +02:00
//
// Author:
// Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//
using MonoFN.Cecil.Metadata;
using MonoFN.Cecil.PE;
using MonoFN.Collections.Generic;
using System;
using System.Collections.Generic;
using RVA = System.UInt32;
namespace MonoFN.Cecil.Cil {
sealed class CodeWriter : ByteBuffer {
readonly RVA code_base;
internal readonly MetadataBuilder metadata;
readonly Dictionary<uint, MetadataToken> standalone_signatures;
readonly Dictionary<ByteBuffer, RVA> tiny_method_bodies;
MethodBody body;
public CodeWriter (MetadataBuilder metadata)
: base (0)
{
this.code_base = metadata.text_map.GetNextRVA (TextSegment.CLIHeader);
this.metadata = metadata;
this.standalone_signatures = new Dictionary<uint, MetadataToken> ();
this.tiny_method_bodies = new Dictionary<ByteBuffer, RVA> (new ByteBufferEqualityComparer ());
}
public RVA WriteMethodBody (MethodDefinition method)
{
RVA rva;
if (IsUnresolved (method)) {
if (method.rva == 0)
return 0;
rva = WriteUnresolvedMethodBody (method);
} else {
if (IsEmptyMethodBody (method.Body))
return 0;
rva = WriteResolvedMethodBody (method);
}
return rva;
}
static bool IsEmptyMethodBody (MethodBody body)
{
return body.instructions.IsNullOrEmpty ()
&& body.variables.IsNullOrEmpty ();
}
static bool IsUnresolved (MethodDefinition method)
{
return method.HasBody && method.HasImage && method.body == null;
}
RVA WriteUnresolvedMethodBody (MethodDefinition method)
{
var code_reader = metadata.module.reader.code;
int code_size;
MetadataToken local_var_token;
var raw_body = code_reader.PatchRawMethodBody (method, this, out code_size, out local_var_token);
var fat_header = (raw_body.buffer [0] & 0x3) == 0x3;
if (fat_header)
Align (4);
var rva = BeginMethod ();
if (fat_header || !GetOrMapTinyMethodBody (raw_body, ref rva)) {
WriteBytes (raw_body);
}
if (method.debug_info == null)
return rva;
var symbol_writer = metadata.symbol_writer;
if (symbol_writer != null) {
method.debug_info.code_size = code_size;
method.debug_info.local_var_token = local_var_token;
symbol_writer.Write (method.debug_info);
}
return rva;
}
RVA WriteResolvedMethodBody (MethodDefinition method)
{
RVA rva;
body = method.Body;
ComputeHeader ();
if (RequiresFatHeader ()) {
Align (4);
rva = BeginMethod ();
WriteFatHeader ();
WriteInstructions ();
if (body.HasExceptionHandlers)
WriteExceptionHandlers ();
} else {
rva = BeginMethod ();
WriteByte ((byte)(0x2 | (body.CodeSize << 2))); // tiny
WriteInstructions ();
var start_position = (int)(rva - code_base);
var body_size = position - start_position;
var body_bytes = new byte [body_size];
Array.Copy (buffer, start_position, body_bytes, 0, body_size);
if (GetOrMapTinyMethodBody (new ByteBuffer (body_bytes), ref rva))
position = start_position;
}
var symbol_writer = metadata.symbol_writer;
if (symbol_writer != null && method.debug_info != null) {
method.debug_info.code_size = body.CodeSize;
method.debug_info.local_var_token = body.local_var_token;
symbol_writer.Write (method.debug_info);
}
return rva;
}
bool GetOrMapTinyMethodBody (ByteBuffer body, ref RVA rva)
{
RVA existing_rva;
if (tiny_method_bodies.TryGetValue (body, out existing_rva)) {
rva = existing_rva;
return true;
}
tiny_method_bodies.Add (body, rva);
return false;
}
void WriteFatHeader ()
{
var body = this.body;
byte flags = 0x3; // fat
if (body.InitLocals)
flags |= 0x10; // init locals
if (body.HasExceptionHandlers)
flags |= 0x8; // more sections
WriteByte (flags);
WriteByte (0x30);
WriteInt16 ((short)body.max_stack_size);
WriteInt32 (body.code_size);
body.local_var_token = body.HasVariables
? GetStandAloneSignature (body.Variables)
: MetadataToken.Zero;
WriteMetadataToken (body.local_var_token);
}
void WriteInstructions ()
{
var instructions = body.Instructions;
var items = instructions.items;
var size = instructions.size;
for (int i = 0; i < size; i++) {
var instruction = items [i];
WriteOpCode (instruction.opcode);
WriteOperand (instruction);
}
}
void WriteOpCode (OpCode opcode)
{
if (opcode.Size == 1) {
WriteByte (opcode.Op2);
} else {
WriteByte (opcode.Op1);
WriteByte (opcode.Op2);
}
}
void WriteOperand (Instruction instruction)
{
var opcode = instruction.opcode;
var operand_type = opcode.OperandType;
if (operand_type == OperandType.InlineNone)
return;
var operand = instruction.operand;
if (operand == null && !(operand_type == OperandType.InlineBrTarget || operand_type == OperandType.ShortInlineBrTarget)) {
throw new ArgumentException ();
}
switch (operand_type) {
case OperandType.InlineSwitch: {
var targets = (Instruction [])operand;
WriteInt32 (targets.Length);
var diff = instruction.Offset + opcode.Size + (4 * (targets.Length + 1));
for (int i = 0; i < targets.Length; i++)
WriteInt32 (GetTargetOffset (targets [i]) - diff);
break;
}
case OperandType.ShortInlineBrTarget: {
var target = (Instruction)operand;
var offset = target != null ? GetTargetOffset (target) : body.code_size;
WriteSByte ((sbyte)(offset - (instruction.Offset + opcode.Size + 1)));
break;
}
case OperandType.InlineBrTarget: {
var target = (Instruction)operand;
var offset = target != null ? GetTargetOffset (target) : body.code_size;
WriteInt32 (offset - (instruction.Offset + opcode.Size + 4));
break;
}
case OperandType.ShortInlineVar:
WriteByte ((byte)GetVariableIndex ((VariableDefinition)operand));
break;
case OperandType.ShortInlineArg:
WriteByte ((byte)GetParameterIndex ((ParameterDefinition)operand));
break;
case OperandType.InlineVar:
WriteInt16 ((short)GetVariableIndex ((VariableDefinition)operand));
break;
case OperandType.InlineArg:
WriteInt16 ((short)GetParameterIndex ((ParameterDefinition)operand));
break;
case OperandType.InlineSig:
WriteMetadataToken (GetStandAloneSignature ((CallSite)operand));
break;
case OperandType.ShortInlineI:
if (opcode == OpCodes.Ldc_I4_S)
WriteSByte ((sbyte)operand);
else
WriteByte ((byte)operand);
break;
case OperandType.InlineI:
WriteInt32 ((int)operand);
break;
case OperandType.InlineI8:
WriteInt64 ((long)operand);
break;
case OperandType.ShortInlineR:
WriteSingle ((float)operand);
break;
case OperandType.InlineR:
WriteDouble ((double)operand);
break;
case OperandType.InlineString:
WriteMetadataToken (
new MetadataToken (
TokenType.String,
GetUserStringIndex ((string)operand)));
break;
case OperandType.InlineType:
case OperandType.InlineField:
case OperandType.InlineMethod:
case OperandType.InlineTok:
WriteMetadataToken (metadata.LookupToken ((IMetadataTokenProvider)operand));
break;
default:
throw new ArgumentException ();
}
}
int GetTargetOffset (Instruction instruction)
{
if (instruction == null) {
var last = body.instructions [body.instructions.size - 1];
return last.offset + last.GetSize ();
}
return instruction.offset;
}
uint GetUserStringIndex (string @string)
{
if (@string == null)
return 0;
return metadata.user_string_heap.GetStringIndex (@string);
}
static int GetVariableIndex (VariableDefinition variable)
{
return variable.Index;
}
int GetParameterIndex (ParameterDefinition parameter)
{
if (body.method.HasThis) {
if (parameter == body.this_parameter)
return 0;
return parameter.Index + 1;
}
return parameter.Index;
}
bool RequiresFatHeader ()
{
var body = this.body;
return body.CodeSize >= 64
|| body.InitLocals
|| body.HasVariables
|| body.HasExceptionHandlers
|| body.MaxStackSize > 8;
}
void ComputeHeader ()
{
int offset = 0;
var instructions = body.instructions;
var items = instructions.items;
var count = instructions.size;
var stack_size = 0;
var max_stack = 0;
Dictionary<Instruction, int> stack_sizes = null;
if (body.HasExceptionHandlers)
ComputeExceptionHandlerStackSize (ref stack_sizes);
for (int i = 0; i < count; i++) {
var instruction = items [i];
instruction.offset = offset;
offset += instruction.GetSize ();
ComputeStackSize (instruction, ref stack_sizes, ref stack_size, ref max_stack);
}
body.code_size = offset;
body.max_stack_size = max_stack;
}
void ComputeExceptionHandlerStackSize (ref Dictionary<Instruction, int> stack_sizes)
{
var exception_handlers = body.ExceptionHandlers;
for (int i = 0; i < exception_handlers.Count; i++) {
var exception_handler = exception_handlers [i];
switch (exception_handler.HandlerType) {
case ExceptionHandlerType.Catch:
AddExceptionStackSize (exception_handler.HandlerStart, ref stack_sizes);
break;
case ExceptionHandlerType.Filter:
AddExceptionStackSize (exception_handler.FilterStart, ref stack_sizes);
AddExceptionStackSize (exception_handler.HandlerStart, ref stack_sizes);
break;
}
}
}
static void AddExceptionStackSize (Instruction handler_start, ref Dictionary<Instruction, int> stack_sizes)
{
if (handler_start == null)
return;
if (stack_sizes == null)
stack_sizes = new Dictionary<Instruction, int> ();
stack_sizes [handler_start] = 1;
}
static void ComputeStackSize (Instruction instruction, ref Dictionary<Instruction, int> stack_sizes, ref int stack_size, ref int max_stack)
{
int computed_size;
if (stack_sizes != null && stack_sizes.TryGetValue (instruction, out computed_size))
stack_size = computed_size;
max_stack = System.Math.Max (max_stack, stack_size);
ComputeStackDelta (instruction, ref stack_size);
max_stack = System.Math.Max (max_stack, stack_size);
CopyBranchStackSize (instruction, ref stack_sizes, stack_size);
ComputeStackSize (instruction, ref stack_size);
}
static void CopyBranchStackSize (Instruction instruction, ref Dictionary<Instruction, int> stack_sizes, int stack_size)
{
if (stack_size == 0)
return;
switch (instruction.opcode.OperandType) {
case OperandType.ShortInlineBrTarget:
case OperandType.InlineBrTarget:
CopyBranchStackSize (ref stack_sizes, (Instruction)instruction.operand, stack_size);
break;
case OperandType.InlineSwitch:
var targets = (Instruction [])instruction.operand;
for (int i = 0; i < targets.Length; i++)
CopyBranchStackSize (ref stack_sizes, targets [i], stack_size);
break;
}
}
static void CopyBranchStackSize (ref Dictionary<Instruction, int> stack_sizes, Instruction target, int stack_size)
{
if (stack_sizes == null)
stack_sizes = new Dictionary<Instruction, int> ();
int branch_stack_size = stack_size;
int computed_size;
if (stack_sizes.TryGetValue (target, out computed_size))
branch_stack_size = System.Math.Max (branch_stack_size, computed_size);
stack_sizes [target] = branch_stack_size;
}
static void ComputeStackSize (Instruction instruction, ref int stack_size)
{
switch (instruction.opcode.FlowControl) {
case FlowControl.Branch:
case FlowControl.Throw:
case FlowControl.Return:
stack_size = 0;
break;
}
}
static void ComputeStackDelta (Instruction instruction, ref int stack_size)
{
switch (instruction.opcode.FlowControl) {
case FlowControl.Call: {
var method = (IMethodSignature)instruction.operand;
// pop 'this' argument
if (method.HasImplicitThis () && instruction.opcode.Code != Code.Newobj)
stack_size--;
// pop normal arguments
if (method.HasParameters)
stack_size -= method.Parameters.Count;
// pop function pointer
if (instruction.opcode.Code == Code.Calli)
stack_size--;
// push return value
if (method.ReturnType.etype != ElementType.Void || instruction.opcode.Code == Code.Newobj)
stack_size++;
break;
}
default:
ComputePopDelta (instruction.opcode.StackBehaviourPop, ref stack_size);
ComputePushDelta (instruction.opcode.StackBehaviourPush, ref stack_size);
break;
}
}
static void ComputePopDelta (StackBehaviour pop_behavior, ref int stack_size)
{
switch (pop_behavior) {
case StackBehaviour.Popi:
case StackBehaviour.Popref:
case StackBehaviour.Pop1:
stack_size--;
break;
case StackBehaviour.Pop1_pop1:
case StackBehaviour.Popi_pop1:
case StackBehaviour.Popi_popi:
case StackBehaviour.Popi_popi8:
case StackBehaviour.Popi_popr4:
case StackBehaviour.Popi_popr8:
case StackBehaviour.Popref_pop1:
case StackBehaviour.Popref_popi:
stack_size -= 2;
break;
case StackBehaviour.Popi_popi_popi:
case StackBehaviour.Popref_popi_popi:
case StackBehaviour.Popref_popi_popi8:
case StackBehaviour.Popref_popi_popr4:
case StackBehaviour.Popref_popi_popr8:
case StackBehaviour.Popref_popi_popref:
stack_size -= 3;
break;
case StackBehaviour.PopAll:
stack_size = 0;
break;
}
}
static void ComputePushDelta (StackBehaviour push_behaviour, ref int stack_size)
{
switch (push_behaviour) {
case StackBehaviour.Push1:
case StackBehaviour.Pushi:
case StackBehaviour.Pushi8:
case StackBehaviour.Pushr4:
case StackBehaviour.Pushr8:
case StackBehaviour.Pushref:
stack_size++;
break;
case StackBehaviour.Push1_push1:
stack_size += 2;
break;
}
}
void WriteExceptionHandlers ()
{
Align (4);
var handlers = body.ExceptionHandlers;
if (handlers.Count < 0x15 && !RequiresFatSection (handlers))
WriteSmallSection (handlers);
else
WriteFatSection (handlers);
}
static bool RequiresFatSection (Collection<ExceptionHandler> handlers)
{
for (int i = 0; i < handlers.Count; i++) {
var handler = handlers [i];
if (IsFatRange (handler.TryStart, handler.TryEnd))
return true;
if (IsFatRange (handler.HandlerStart, handler.HandlerEnd))
return true;
if (handler.HandlerType == ExceptionHandlerType.Filter
&& IsFatRange (handler.FilterStart, handler.HandlerStart))
return true;
}
return false;
}
static bool IsFatRange (Instruction start, Instruction end)
{
if (start == null)
throw new ArgumentException ();
if (end == null)
return true;
return end.Offset - start.Offset > 255 || start.Offset > 65535;
}
void WriteSmallSection (Collection<ExceptionHandler> handlers)
{
const byte eh_table = 0x1;
WriteByte (eh_table);
WriteByte ((byte)(handlers.Count * 12 + 4));
WriteBytes (2);
WriteExceptionHandlers (
handlers,
i => WriteUInt16 ((ushort)i),
i => WriteByte ((byte)i));
}
void WriteFatSection (Collection<ExceptionHandler> handlers)
{
const byte eh_table = 0x1;
const byte fat_format = 0x40;
WriteByte (eh_table | fat_format);
int size = handlers.Count * 24 + 4;
WriteByte ((byte)(size & 0xff));
WriteByte ((byte)((size >> 8) & 0xff));
WriteByte ((byte)((size >> 16) & 0xff));
WriteExceptionHandlers (handlers, WriteInt32, WriteInt32);
}
void WriteExceptionHandlers (Collection<ExceptionHandler> handlers, Action<int> write_entry, Action<int> write_length)
{
for (int i = 0; i < handlers.Count; i++) {
var handler = handlers [i];
write_entry ((int)handler.HandlerType);
write_entry (handler.TryStart.Offset);
write_length (GetTargetOffset (handler.TryEnd) - handler.TryStart.Offset);
write_entry (handler.HandlerStart.Offset);
write_length (GetTargetOffset (handler.HandlerEnd) - handler.HandlerStart.Offset);
WriteExceptionHandlerSpecific (handler);
}
}
void WriteExceptionHandlerSpecific (ExceptionHandler handler)
{
switch (handler.HandlerType) {
case ExceptionHandlerType.Catch:
WriteMetadataToken (metadata.LookupToken (handler.CatchType));
break;
case ExceptionHandlerType.Filter:
WriteInt32 (handler.FilterStart.Offset);
break;
default:
WriteInt32 (0);
break;
}
}
public MetadataToken GetStandAloneSignature (Collection<VariableDefinition> variables)
{
var signature = metadata.GetLocalVariableBlobIndex (variables);
return GetStandAloneSignatureToken (signature);
}
public MetadataToken GetStandAloneSignature (CallSite call_site)
{
var signature = metadata.GetCallSiteBlobIndex (call_site);
var token = GetStandAloneSignatureToken (signature);
call_site.MetadataToken = token;
return token;
}
MetadataToken GetStandAloneSignatureToken (uint signature)
{
MetadataToken token;
if (standalone_signatures.TryGetValue (signature, out token))
return token;
token = new MetadataToken (TokenType.Signature, metadata.AddStandAloneSignature (signature));
standalone_signatures.Add (signature, token);
return token;
}
RVA BeginMethod ()
{
return (RVA)(code_base + position);
}
void WriteMetadataToken (MetadataToken token)
{
WriteUInt32 (token.ToUInt32 ());
}
void Align (int align)
{
align--;
WriteBytes (((position + align) & ~align) - position);
}
}
}