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                                 if (Annotations.GetAction (assembly) == AssemblyAction.Copy) {
  48                                         // Copy assemblies can still contain Type references with
  49                                         // type forwarders from Delete assemblies
  50                                         // thus try to resolve all the type references and see
  51                                         // if some changed the scope. if yes change the action to Save
  52                                         if (ResolveAllTypeReferences (assembly))
  53                                                 Annotations.SetAction (assembly, AssemblyAction.Save);
  54                                 }
  55                         }
  56                 }
  57
  58                 void SweepAssembly (AssemblyDefinition assembly)
  59                 {
  60                         if (Annotations.GetAction (assembly) != AssemblyAction.Link)
  61                                 return;
  62
  63                         if (!IsMarkedAssembly (assembly)) {
  64                                 RemoveAssembly (assembly);
  65                                 return;
  66                         }
  67
  68                         var types = new List<TypeDefinition> ();
  69
  70                         foreach (TypeDefinition type in assembly.MainModule.Types) {
  71                                 if (Annotations.IsMarked (type)) {
  72                                         SweepType (type);
  73                                         types.Add (type);
  74                                         continue;
  75                                 }
  76
  77                                 if (type.Name == "<Module>")
  78                                         types.Add (type);
  79                         }
  80
  81                         assembly.MainModule.Types.Clear ();
  82                         foreach (TypeDefinition type in types)
  83                                 assembly.MainModule.Types.Add (type);
  84                 }
  85
  86                 bool IsMarkedAssembly (AssemblyDefinition assembly)
  87                 {
  88                         return Annotations.IsMarked (assembly.MainModule);
  89                 }
  90
  91                 void RemoveAssembly (AssemblyDefinition assembly)
  92                 {
  93                         Annotations.SetAction (assembly, AssemblyAction.Delete);
  94
  95                         SweepReferences (assembly);
  96                 }
  97
  98                 void SweepReferences (AssemblyDefinition target)
  99                 {
 100                         foreach (var assembly in assemblies)
 101                                 SweepReferences (assembly, target);
 102                 }
 103
 104                 void SweepReferences (AssemblyDefinition assembly, AssemblyDefinition target)
 105                 {
 106                         if (assembly == target)
 107                                 return;
 108
 109                         var references = assembly.MainModule.AssemblyReferences;
 110                         for (int i = 0; i < references.Count; i++) {
 111                                 var reference = references [i];
 112                                 var r = Context.Resolver.Resolve (reference);
 113                                 if (!AreSameReference (r.Name, target.Name))
 114                                         continue;
 115
 116                                 references.RemoveAt (i);
 117                                 // Removing the reference does not mean it will be saved back to disk!
 118                                 // That depends on the AssemblyAction set for the `assembly`
 119                                 switch (Annotations.GetAction (assembly)) {
 120                                 case AssemblyAction.Copy:
 121                                         // Copy means even if "unlinked" we still want that assembly to be saved back
 122                                         // to disk (OutputStep) without the (removed) reference
 123                                         Annotations.SetAction (assembly, AssemblyAction.Save);
 124                                         ResolveAllTypeReferences (assembly);
 125                                         break;
 126
 127                                 case AssemblyAction.Save:
 128                                 case AssemblyAction.Link:
 129                                         ResolveAllTypeReferences (assembly);
 130                                         break;
 131                                 }
 132                                 return;
 133                         }
 134                 }
 135
 136                 bool ResolveAllTypeReferences (AssemblyDefinition assembly)
 137                 {
 138                         if (resolvedTypeReferences == null)
 139                                 resolvedTypeReferences = new HashSet<AssemblyDefinition> ();
 140                         if (resolvedTypeReferences.Contains (assembly))
 141                                 return false;
 142                         resolvedTypeReferences.Add (assembly);
 143
 144                         var hash = new Dictionary<TypeReference,IMetadataScope> ();
 145                         bool changes = false;
 146
 147                         foreach (TypeReference tr in assembly.MainModule.GetTypeReferences ()) {
 148                                 if (hash.ContainsKey (tr))
 149                                         continue;
 150                                 var td = tr.Resolve ();
 151                                 IMetadataScope scope = tr.Scope;
 152                                 // at this stage reference might include things that can't be resolved
 153                                 // and if it is (resolved) it needs to be kept only if marked (#16213)
 154                                 if ((td != null) && Annotations.IsMarked (td)) {
 155                                         scope = assembly.MainModule.ImportReference (td).Scope;
 156                                         if (tr.Scope != scope)
 157                                                 changes = true;
 158                                         hash.Add (tr, scope);
 159                                 }
 160                         }
 161                         if (assembly.MainModule.HasExportedTypes) {
 162                                 foreach (var et in assembly.MainModule.ExportedTypes) {
 163                                         var td = et.Resolve ();
 164                                         IMetadataScope scope = et.Scope;
 165                                         if ((td != null) && Annotations.IsMarked (td)) {
 166                                                 scope = assembly.MainModule.ImportReference (td).Scope;
 167                                                 hash.Add (td, scope);
 168                                         }
 169                                 }
 170                         }
 171
 172                         // Resolve everything first before updating scopes.
 173                         // If we set the scope to null, then calling Resolve() on any of its
 174                         // nested types would crash.
 175
 176                         foreach (var e in hash) {
 177                                 e.Key.Scope = e.Value;
 178                         }
 179
 180                         return changes;
 181                 }
 182
 183                 void SweepType (TypeDefinition type)
 184                 {
 185                         if (type.HasFields)
 186                                 SweepCollection (type.Fields);
 187
 188                         if (type.HasMethods)
 189                                 SweepCollection (type.Methods);
 190
 191                         if (type.HasNestedTypes)
 192                                 SweepNestedTypes (type);
 193                 }
 194
 195                 void SweepNestedTypes (TypeDefinition type)
 196                 {
 197                         for (int i = 0; i < type.NestedTypes.Count; i++) {
 198                                 var nested = type.NestedTypes [i];
 199                                 if (Annotations.IsMarked (nested)) {
 200                                         SweepType (nested);
 201                                 } else {
 202                                         type.NestedTypes.RemoveAt (i--);
 203                                 }
 204                         }
 205                 }
 206
 207                 void SweepCollection (IList list)
 208                 {
 209                         for (int i = 0; i < list.Count; i++)
 210                                 if (!Annotations.IsMarked ((IMetadataTokenProvider) list [i]))
 211                                         list.RemoveAt (i--);
 212                 }
 213
 214                 static bool AreSameReference (AssemblyNameReference a, AssemblyNameReference b)
 215                 {
 216                         if (a == b)
 217                                 return true;
 218
 219                         if (a.Name != b.Name)
 220                                 return false;
 221
 222                         if (a.Version > b.Version)
 223                                 return false;
 224
 225                         return true;
 226                 }
 227         }
 228 }