mcs/tools/cil-strip/Mono.Cecil.Cil/CodeReader.cs

   1 //
   2 // CodeReader.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@gmail.com)
   6 //
   7 // (C) 2005 - 2007 Jb Evain
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 namespace Mono.Cecil.Cil {
  30
  31         using System;
  32         using System.Collections;
  33         using System.IO;
  34
  35         using Mono.Cecil;
  36         using Mono.Cecil.Metadata;
  37         using Mono.Cecil.Signatures;
  38
  39         sealed class CodeReader : BaseCodeVisitor {
  40
  41                 ReflectionReader m_reflectReader;
  42                 MetadataRoot m_root;
  43                 IDictionary m_instructions;
  44
  45                 public CodeReader (ReflectionReader reflectReader)
  46                 {
  47                         m_reflectReader = reflectReader;
  48                         m_root = m_reflectReader.MetadataRoot;
  49                         m_instructions = new Hashtable ();
  50                 }
  51
  52                 public override void VisitMethodBody (MethodBody body)
  53                 {
  54                         MethodDefinition meth = body.Method;
  55                         MethodBody methBody = body;
  56                         BinaryReader br = m_reflectReader.Module.ImageReader.MetadataReader.GetDataReader (meth.RVA);
  57
  58                         // lets read the method
  59                         int flags = br.ReadByte ();
  60                         switch (flags & 0x3) {
  61                         case (int) MethodHeader.TinyFormat :
  62                                 methBody.CodeSize = flags >> 2;
  63                                 methBody.MaxStack = 8;
  64                                 ReadCilBody (methBody, br);
  65                                 break;
  66                         case (int) MethodHeader.FatFormat :
  67                                 br.BaseStream.Position--;
  68                                 int fatflags = br.ReadUInt16 ();
  69                                 //int headersize = (fatflags >> 12) & 0xf;
  70                                 methBody.MaxStack = br.ReadUInt16 ();
  71                                 methBody.CodeSize = br.ReadInt32 ();
  72                                 methBody.LocalVarToken = br.ReadInt32 ();
  73                                 body.InitLocals = (fatflags & (int) MethodHeader.InitLocals) != 0;
  74                                 if (methBody.LocalVarToken != 0)
  75                                         VisitVariableDefinitionCollection (methBody.Variables);
  76                                 ReadCilBody (methBody, br);
  77                                 if ((fatflags & (int) MethodHeader.MoreSects) != 0)
  78                                         ReadSection (methBody, br);
  79                                 break;
  80                         }
  81                 }
  82
  83                 public static uint GetRid (int token)
  84                 {
  85                         return (uint) token & 0x00ffffff;
  86                 }
  87
  88                 public static ParameterDefinition GetParameter (MethodBody body, int index)
  89                 {
  90                         if (body.Method.HasThis) {
  91                                 if (index == 0)
  92                                         return body.Method.This;
  93                                 index--;
  94                         }
  95
  96                         return body.Method.Parameters [index];
  97                 }
  98
  99                 public static VariableDefinition GetVariable (MethodBody body, int index)
 100                 {
 101                         // bug 15727 - newer cecil does the same (in MethodDefinition.GetVariable)
 102                         var variables = body.Variables;
 103                         if (index < 0 || index >= variables.Count)
 104                                 return null;
 105                         return variables [index];
 106                 }
 107
 108                 void ReadCilBody (MethodBody body, BinaryReader br)
 109                 {
 110                         long start = br.BaseStream.Position;
 111                         Instruction last = null;
 112                         m_instructions.Clear();
 113                         InstructionCollection code = body.Instructions;
 114                         GenericContext context = new GenericContext (body.Method);
 115
 116                         while (br.BaseStream.Position < start + body.CodeSize) {
 117                                 OpCode op;
 118                                 long offset = br.BaseStream.Position - start;
 119                                 int cursor = br.ReadByte ();
 120                                 if (cursor == 0xfe)
 121                                         op = OpCodes.TwoBytesOpCode [br.ReadByte ()];
 122                                 else
 123                                         op = OpCodes.OneByteOpCode [cursor];
 124
 125                                 Instruction instr = new Instruction ((int) offset, op);
 126                                 switch (op.OperandType) {
 127                                 case OperandType.InlineNone :
 128                                         break;
 129                                 case OperandType.InlineSwitch :
 130                                         uint length = br.ReadUInt32 ();
 131                                         int [] branches = new int [length];
 132                                         int [] buf = new int [length];
 133                                         for (int i = 0; i < length; i++)
 134                                                 buf [i] = br.ReadInt32 ();
 135                                         for (int i = 0; i < length; i++)
 136                                                 branches [i] = Convert.ToInt32 (br.BaseStream.Position - start + buf [i]);
 137                                         instr.Operand = branches;
 138                                         break;
 139                                 case OperandType.ShortInlineBrTarget :
 140                                         sbyte sbrtgt = br.ReadSByte ();
 141                                         instr.Operand = Convert.ToInt32 (br.BaseStream.Position - start + sbrtgt);
 142                                         break;
 143                                 case OperandType.InlineBrTarget :
 144                                         int brtgt = br.ReadInt32 ();
 145                                         instr.Operand = Convert.ToInt32 (br.BaseStream.Position - start + brtgt);
 146                                         break;
 147                                 case OperandType.ShortInlineI :
 148                                         if (op == OpCodes.Ldc_I4_S)
 149                                                 instr.Operand = br.ReadSByte ();
 150                                         else
 151                                                 instr.Operand = br.ReadByte ();
 152                                         break;
 153                                 case OperandType.ShortInlineVar :
 154                                         instr.Operand = GetVariable (body, br.ReadByte ());
 155                                         break;
 156                                 case OperandType.ShortInlineParam :
 157                                         instr.Operand = GetParameter (body, br.ReadByte ());
 158                                         break;
 159                                 case OperandType.InlineSig :
 160                                         instr.Operand = GetCallSiteAt (br.ReadInt32 (), context);
 161                                         break;
 162                                 case OperandType.InlineI :
 163                                         instr.Operand = br.ReadInt32 ();
 164                                         break;
 165                                 case OperandType.InlineVar :
 166                                         instr.Operand = GetVariable (body, br.ReadInt16 ());
 167                                         break;
 168                                 case OperandType.InlineParam :
 169                                         instr.Operand = GetParameter (body, br.ReadInt16 ());
 170                                         break;
 171                                 case OperandType.InlineI8 :
 172                                         instr.Operand = br.ReadInt64 ();
 173                                         break;
 174                                 case OperandType.ShortInlineR :
 175                                         instr.Operand = br.ReadSingle ();
 176                                         break;
 177                                 case OperandType.InlineR :
 178                                         instr.Operand = br.ReadDouble ();
 179                                         break;
 180                                 case OperandType.InlineString :
 181                                         instr.Operand = m_root.Streams.UserStringsHeap [GetRid (br.ReadInt32 ())];
 182                                         break;
 183                                 case OperandType.InlineField :
 184                                 case OperandType.InlineMethod :
 185                                 case OperandType.InlineType :
 186                                 case OperandType.InlineTok :
 187                                         MetadataToken token = new MetadataToken (br.ReadInt32 ());
 188                                         switch (token.TokenType) {
 189                                         case TokenType.TypeDef:
 190                                                 instr.Operand = m_reflectReader.GetTypeDefAt (token.RID);
 191                                                 break;
 192                                         case TokenType.TypeRef:
 193                                                 instr.Operand = m_reflectReader.GetTypeRefAt (token.RID);
 194                                                 break;
 195                                         case TokenType.TypeSpec:
 196                                                 instr.Operand = m_reflectReader.GetTypeSpecAt (token.RID, context);
 197                                                 break;
 198                                         case TokenType.Field:
 199                                                 instr.Operand = m_reflectReader.GetFieldDefAt (token.RID);
 200                                                 break;
 201                                         case TokenType.Method:
 202                                                 instr.Operand = m_reflectReader.GetMethodDefAt (token.RID);
 203                                                 break;
 204                                         case TokenType.MethodSpec:
 205                                                 instr.Operand = m_reflectReader.GetMethodSpecAt (token.RID, context);
 206                                                 break;
 207                                         case TokenType.MemberRef:
 208                                                 instr.Operand = m_reflectReader.GetMemberRefAt (token.RID, context);
 209                                                 break;
 210                                         default:
 211                                                 throw new ReflectionException ("Wrong token: " + token);
 212                                         }
 213                                         break;
 214                                 }
 215
 216                                 m_instructions.Add (instr.Offset, instr);
 217
 218                                 if (last != null) {
 219                                         last.Next = instr;
 220                                         instr.Previous = last;
 221                                 }
 222
 223                                 last = instr;
 224
 225                                 code.Add (instr);
 226                         }
 227
 228                         // resolve branches
 229                         foreach (Instruction i in code) {
 230                                 switch (i.OpCode.OperandType) {
 231                                 case OperandType.ShortInlineBrTarget:
 232                                 case OperandType.InlineBrTarget:
 233                                         i.Operand = GetInstruction (body, (int) i.Operand);
 234                                         break;
 235                                 case OperandType.InlineSwitch:
 236                                         int [] lbls = (int []) i.Operand;
 237                                         Instruction [] instrs = new Instruction [lbls.Length];
 238                                         for (int j = 0; j < lbls.Length; j++)
 239                                                 instrs [j] = GetInstruction (body, lbls [j]);
 240                                         i.Operand = instrs;
 241                                         break;
 242                                 }
 243                         }
 244
 245                         if (m_reflectReader.SymbolReader != null)
 246                                 m_reflectReader.SymbolReader.Read (body, m_instructions);
 247                 }
 248
 249                 Instruction GetInstruction (MethodBody body, int offset)
 250                 {
 251                         Instruction instruction = m_instructions [offset] as Instruction;
 252                         if (instruction != null)
 253                                 return instruction;
 254
 255                         return body.Instructions.Outside;
 256                 }
 257
 258                 void ReadSection (MethodBody body, BinaryReader br)
 259                 {
 260                         br.BaseStream.Position += 3;
 261                         br.BaseStream.Position &= ~3;
 262
 263                         byte flags = br.ReadByte ();
 264                         if ((flags & (byte) MethodDataSection.FatFormat) == 0) {
 265                                 int length = br.ReadByte () / 12;
 266                                 br.ReadBytes (2);
 267
 268                                 for (int i = 0; i < length; i++) {
 269                                         ExceptionHandler eh = new ExceptionHandler (
 270                                                 (ExceptionHandlerType) (br.ReadInt16 () & 0x7));
 271                                         eh.TryStart = GetInstruction (body, Convert.ToInt32 (br.ReadInt16 ()));
 272                                         eh.TryEnd = GetInstruction (body, eh.TryStart.Offset + Convert.ToInt32 (br.ReadByte ()));
 273                                         eh.HandlerStart = GetInstruction (body, Convert.ToInt32 (br.ReadInt16 ()));
 274                                         eh.HandlerEnd = GetInstruction (body, eh.HandlerStart.Offset + Convert.ToInt32 (br.ReadByte ()));
 275                                         ReadExceptionHandlerEnd (eh, br, body);
 276                                         body.ExceptionHandlers.Add (eh);
 277                                 }
 278                         } else {
 279                                 br.BaseStream.Position--;
 280                                 int length = (br.ReadInt32 () >> 8) / 24;
 281                                 if ((flags & (int) MethodDataSection.EHTable) == 0)
 282                                         br.ReadBytes (length * 24);
 283                                 for (int i = 0; i < length; i++) {
 284                                         ExceptionHandler eh = new ExceptionHandler (
 285                                                 (ExceptionHandlerType) (br.ReadInt32 () & 0x7));
 286                                         eh.TryStart = GetInstruction (body, br.ReadInt32 ());
 287                                         eh.TryEnd = GetInstruction (body, eh.TryStart.Offset + br.ReadInt32 ());
 288                                         eh.HandlerStart = GetInstruction (body, br.ReadInt32 ());
 289                                         eh.HandlerEnd = GetInstruction (body, eh.HandlerStart.Offset + br.ReadInt32 ());
 290                                         ReadExceptionHandlerEnd (eh, br, body);
 291                                         body.ExceptionHandlers.Add (eh);
 292                                 }
 293                         }
 294
 295                         if ((flags & (byte) MethodDataSection.MoreSects) != 0)
 296                                 ReadSection (body, br);
 297                 }
 298
 299                 void ReadExceptionHandlerEnd (ExceptionHandler eh, BinaryReader br, MethodBody body)
 300                 {
 301                         switch (eh.Type) {
 302                         case ExceptionHandlerType.Catch :
 303                                 MetadataToken token = new MetadataToken (br.ReadInt32 ());
 304                                 eh.CatchType = m_reflectReader.GetTypeDefOrRef (token, new GenericContext (body.Method));
 305                                 break;
 306                         case ExceptionHandlerType.Filter :
 307                                 eh.FilterStart = GetInstruction (body, br.ReadInt32 ());
 308                                 eh.FilterEnd = GetInstruction (body, eh.HandlerStart.Previous.Offset);
 309                                 break;
 310                         default :
 311                                 br.ReadInt32 ();
 312                                 break;
 313                         }
 314                 }
 315
 316                 CallSite GetCallSiteAt (int token, GenericContext context)
 317                 {
 318                         StandAloneSigTable sasTable = m_reflectReader.TableReader.GetStandAloneSigTable ();
 319                         MethodSig ms = m_reflectReader.SigReader.GetStandAloneMethodSig (
 320                                 sasTable [(int) GetRid (token) - 1].Signature);
 321                         CallSite cs = new CallSite (ms.HasThis, ms.ExplicitThis,
 322                                 ms.MethCallConv, m_reflectReader.GetMethodReturnType (ms, context));
 323                         cs.MetadataToken = new MetadataToken (token);
 324
 325                         for (int i = 0; i < ms.ParamCount; i++) {
 326                                 Param p = ms.Parameters [i];
 327                                 cs.Parameters.Add (m_reflectReader.BuildParameterDefinition (i, p, context));
 328                         }
 329
 330                         ReflectionReader.CreateSentinelIfNeeded (cs, ms);
 331
 332                         return cs;
 333                 }
 334
 335                 public override void VisitVariableDefinitionCollection (VariableDefinitionCollection variables)
 336                 {
 337                         MethodBody body = variables.Container as MethodBody;
 338                         if (body == null || body.LocalVarToken == 0)
 339                                 return;
 340
 341                         StandAloneSigTable sasTable = m_reflectReader.TableReader.GetStandAloneSigTable ();
 342                         StandAloneSigRow sasRow = sasTable [(int) GetRid (body.LocalVarToken) - 1];
 343                         LocalVarSig sig = m_reflectReader.SigReader.GetLocalVarSig (sasRow.Signature);
 344                         for (int i = 0; i < sig.Count; i++) {
 345                                 LocalVarSig.LocalVariable lv = sig.LocalVariables [i];
 346                                 TypeReference varType = m_reflectReader.GetTypeRefFromSig (
 347                                         lv.Type, new GenericContext (body.Method));
 348
 349                                 if (lv.ByRef)
 350                                         varType = new ReferenceType (varType);
 351                                 if ((lv.Constraint & Constraint.Pinned) != 0)
 352                                         varType = new PinnedType (varType);
 353
 354                                 varType = m_reflectReader.GetModifierType (lv.CustomMods, varType);
 355
 356                                 body.Variables.Add (new VariableDefinition (
 357                                                 string.Concat ("V_", i), i, body.Method, varType));
 358                         }
 359                 }
 360         }
 361 }