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                 HashSet<AssemblyDefinition> resolvedTypeReferences;
  41
  42                 protected override void Process ()
  43                 {
  44                         assemblies = Context.GetAssemblies ();
  45                         foreach (var assembly in assemblies)
  46                                 SweepAssembly (assembly);
  47                 }
  48
  49                 void SweepAssembly (AssemblyDefinition assembly)
  50                 {
  51                         if (Annotations.GetAction (assembly) != AssemblyAction.Link)
  52                                 return;
  53
  54                         if (!IsMarkedAssembly (assembly)) {
  55                                 RemoveAssembly (assembly);
  56                                 return;
  57                         }
  58
  59                         var types = new List<TypeDefinition> ();
  60
  61                         foreach (TypeDefinition type in assembly.MainModule.Types) {
  62                                 if (Annotations.IsMarked (type)) {
  63                                         SweepType (type);
  64                                         types.Add (type);
  65                                         continue;
  66                                 }
  67
  68                                 if (type.Name == "<Module>")
  69                                         types.Add (type);
  70                         }
  71
  72                         assembly.MainModule.Types.Clear ();
  73                         foreach (TypeDefinition type in types)
  74                                 assembly.MainModule.Types.Add (type);
  75                 }
  76
  77                 bool IsMarkedAssembly (AssemblyDefinition assembly)
  78                 {
  79                         return Annotations.IsMarked (assembly.MainModule);
  80                 }
  81
  82                 void RemoveAssembly (AssemblyDefinition assembly)
  83                 {
  84                         Annotations.SetAction (assembly, AssemblyAction.Delete);
  85
  86                         SweepReferences (assembly);
  87                 }
  88
  89                 void SweepReferences (AssemblyDefinition target)
  90                 {
  91                         foreach (var assembly in assemblies)
  92                                 SweepReferences (assembly, target);
  93                 }
  94
  95                 void SweepReferences (AssemblyDefinition assembly, AssemblyDefinition target)
  96                 {
  97                         if (assembly == target)
  98                                 return;
  99
 100                         var references = assembly.MainModule.AssemblyReferences;
 101                         for (int i = 0; i < references.Count; i++) {
 102                                 var reference = references [i];
 103                                 var r = Context.Resolver.Resolve (reference);
 104                                 if (!AreSameReference (r.Name, target.Name))
 105                                         continue;
 106
 107                                 references.RemoveAt (i);
 108                                 // Removing the reference does not mean it will be saved back to disk!
 109                                 // That depends on the AssemblyAction set for the `assembly`
 110                                 switch (Annotations.GetAction (assembly)) {
 111                                 case AssemblyAction.Copy:
 112                                         // Copy means even if "unlinked" we still want that assembly to be saved back
 113                                         // to disk (OutputStep) without the (removed) reference
 114                                         Annotations.SetAction (assembly, AssemblyAction.Save);
 115                                         ResolveAllTypeReferences (assembly);
 116                                         break;
 117
 118                                 case AssemblyAction.Save:
 119                                 case AssemblyAction.Link:
 120                                         ResolveAllTypeReferences (assembly);
 121                                         break;
 122                                 }
 123                                 return;
 124                         }
 125                 }
 126
 127                 void ResolveAllTypeReferences (AssemblyDefinition assembly)
 128                 {
 129                         if (resolvedTypeReferences == null)
 130                                 resolvedTypeReferences = new HashSet<AssemblyDefinition> ();
 131                         if (resolvedTypeReferences.Contains (assembly))
 132                                 return;
 133                         resolvedTypeReferences.Add (assembly);
 134
 135                         var hash = new Dictionary<TypeReference,IMetadataScope> ();
 136
 137                         foreach (TypeReference tr in assembly.MainModule.GetTypeReferences ()) {
 138                                 if (hash.ContainsKey (tr))
 139                                         continue;
 140                                 var td = tr.Resolve ();
 141                                 IMetadataScope scope = tr.Scope;
 142                                 // at this stage reference might include things that can't be resolved
 143                                 // and if it is (resolved) it needs to be kept only if marked (#16213)
 144                                 if ((td != null) && Annotations.IsMarked (td))
 145                                         scope = assembly.MainModule.Import (td).Scope;
 146                                 hash.Add (tr, scope);
 147                         }
 148                         if (assembly.MainModule.HasExportedTypes) {
 149                                 foreach (var et in assembly.MainModule.ExportedTypes) {
 150                                         var td = et.Resolve ();
 151                                         IMetadataScope scope = et.Scope;
 152                                         if ((td != null) && Annotations.IsMarked (td)) {
 153                                                 scope = assembly.MainModule.Import (td).Scope;
 154                                                 hash.Add (td, scope);
 155                                         }
 156                                 }
 157                         }
 158
 159                         // Resolve everything first before updating scopes.
 160                         // If we set the scope to null, then calling Resolve() on any of its
 161                         // nested types would crash.
 162
 163                         foreach (var e in hash) {
 164                                 e.Key.Scope = e.Value;
 165                         }
 166                 }
 167
 168                 void SweepType (TypeDefinition type)
 169                 {
 170                         if (type.HasFields)
 171                                 SweepCollection (type.Fields);
 172
 173                         if (type.HasMethods)
 174                                 SweepCollection (type.Methods);
 175
 176                         if (type.HasNestedTypes)
 177                                 SweepNestedTypes (type);
 178                 }
 179
 180                 void SweepNestedTypes (TypeDefinition type)
 181                 {
 182                         for (int i = 0; i < type.NestedTypes.Count; i++) {
 183                                 var nested = type.NestedTypes [i];
 184                                 if (Annotations.IsMarked (nested)) {
 185                                         SweepType (nested);
 186                                 } else {
 187                                         type.NestedTypes.RemoveAt (i--);
 188                                 }
 189                         }
 190                 }
 191
 192                 void SweepCollection (IList list)
 193                 {
 194                         for (int i = 0; i < list.Count; i++)
 195                                 if (!Annotations.IsMarked ((IMetadataTokenProvider) list [i]))
 196                                         list.RemoveAt (i--);
 197                 }
 198
 199                 static bool AreSameReference (AssemblyNameReference a, AssemblyNameReference b)
 200                 {
 201                         if (a == b)
 202                                 return true;
 203
 204                         if (a.Name != b.Name)
 205                                 return false;
 206
 207                         if (a.Version > b.Version)
 208                                 return false;
 209
 210                         return true;
 211                 }
 212         }
 213 }