mcs/tools/linker/Mono.Linker.Steps/SweepStep.cs

   1 //
   2 // SweepStep.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@gmail.com)
   6 //
   7 // (C) 2006 Jb Evain
   8 // (C) 2007 Novell, Inc.
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System.Collections;
  31 using System.Collections.Generic;
  32 using Mono.Cecil;
  33 using Mono.Collections.Generic;
  34
  35 namespace Mono.Linker.Steps {
  36
  37         public class SweepStep : BaseStep {
  38
  39                 AssemblyDefinition [] assemblies;
  40
  41                 protected override void Process ()
  42                 {
  43                         assemblies = Context.GetAssemblies ();
  44                         foreach (var assembly in assemblies)
  45                                 SweepAssembly (assembly);
  46                 }
  47
  48                 void SweepAssembly (AssemblyDefinition assembly)
  49                 {
  50                         if (Annotations.GetAction (assembly) != AssemblyAction.Link)
  51                                 return;
  52
  53                         if (!IsMarkedAssembly (assembly)) {
  54                                 RemoveAssembly (assembly);
  55                                 return;
  56                         }
  57
  58                         var types = new List<TypeDefinition> ();
  59
  60                         foreach (TypeDefinition type in assembly.MainModule.Types) {
  61                                 if (Annotations.IsMarked (type)) {
  62                                         SweepType (type);
  63                                         types.Add (type);
  64                                         continue;
  65                                 }
  66
  67                                 if (type.Name == "<Module>")
  68                                         types.Add (type);
  69                         }
  70
  71                         assembly.MainModule.Types.Clear ();
  72                         foreach (TypeDefinition type in types)
  73                                 assembly.MainModule.Types.Add (type);
  74                 }
  75
  76                 bool IsMarkedAssembly (AssemblyDefinition assembly)
  77                 {
  78                         return Annotations.IsMarked (assembly.MainModule);
  79                 }
  80
  81                 void RemoveAssembly (AssemblyDefinition assembly)
  82                 {
  83                         Annotations.SetAction (assembly, AssemblyAction.Delete);
  84
  85                         SweepReferences (assembly);
  86                 }
  87
  88                 void SweepReferences (AssemblyDefinition target)
  89                 {
  90                         foreach (var assembly in assemblies)
  91                                 SweepReferences (assembly, target);
  92                 }
  93
  94                 void SweepReferences (AssemblyDefinition assembly, AssemblyDefinition target)
  95                 {
  96                         var references = assembly.MainModule.AssemblyReferences;
  97                         for (int i = 0; i < references.Count; i++) {
  98                                 var reference = references [i];
  99                                 if (!AreSameReference (reference, target.Name))
 100                                         continue;
 101
 102                                 references.RemoveAt (i);
 103                                 // Removing the reference does not mean it will be saved back to disk!
 104                                 // That depends on the AssemblyAction set for the `assembly`
 105                                 if (Annotations.GetAction (assembly) == AssemblyAction.Copy) {
 106                                         // Copy means even if "unlinked" we still want that assembly to be saved back
 107                                         // to disk (OutputStep) without the (removed) reference
 108                                         Annotations.SetAction (assembly, AssemblyAction.Save);
 109                                         // note: we only enter here (Copy->Save once) so we nned to do the complete job
 110                                         foreach (TypeReference tr in assembly.MainModule.GetTypeReferences ()) {
 111                                                 var td = tr.Resolve ();
 112                                                 // at this stage reference might include things that can't be resolved
 113                                                 tr.Scope = td == null ? null : assembly.MainModule.Import (td).Scope;
 114                                         }
 115                                 }
 116                                 return;
 117                         }
 118                 }
 119
 120                 void SweepType (TypeDefinition type)
 121                 {
 122                         if (type.HasFields)
 123                                 SweepCollection (type.Fields);
 124
 125                         if (type.HasMethods)
 126                                 SweepCollection (type.Methods);
 127
 128                         if (type.HasNestedTypes)
 129                                 SweepNestedTypes (type);
 130                 }
 131
 132                 void SweepNestedTypes (TypeDefinition type)
 133                 {
 134                         for (int i = 0; i < type.NestedTypes.Count; i++) {
 135                                 var nested = type.NestedTypes [i];
 136                                 if (Annotations.IsMarked (nested)) {
 137                                         SweepType (nested);
 138                                 } else {
 139                                         type.NestedTypes.RemoveAt (i--);
 140                                 }
 141                         }
 142                 }
 143
 144                 void SweepCollection (IList list)
 145                 {
 146                         for (int i = 0; i < list.Count; i++)
 147                                 if (!Annotations.IsMarked ((IMetadataTokenProvider) list [i]))
 148                                         list.RemoveAt (i--);
 149                 }
 150
 151                 static bool AreSameReference (AssemblyNameReference a, AssemblyNameReference b)
 152                 {
 153                         if (a == b)
 154                                 return true;
 155
 156                         if (a.Name != b.Name)
 157                                 return false;
 158
 159                         if (a.Version > b.Version)
 160                                 return false;
 161
 162                         return true;
 163                 }
 164         }
 165 }