tools/clang/blink_gc_plugin/RecordInfo.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file provides a wrapper for CXXRecordDecl that accumulates GC related
   6 // information about a class. Accumulated information is memoized and the info
   7 // objects are stored in a RecordCache.
   8
   9 #ifndef TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_
  10 #define TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_
  11
  12 #include <map>
  13 #include <vector>
  14
  15 #include "Edge.h"
  16
  17 #include "clang/AST/AST.h"
  18 #include "clang/AST/CXXInheritance.h"
  19
  20 class RecordCache;
  21
  22 // A potentially tracable and/or lifetime affecting point in the object graph.
  23 class GraphPoint {
  24  public:
  25   GraphPoint() : traced_(false) {}
  26   virtual ~GraphPoint() {}
  27   void MarkTraced() { traced_ = true; }
  28   bool IsProperlyTraced() { return traced_ || !NeedsTracing().IsNeeded(); }
  29   virtual const TracingStatus NeedsTracing() = 0;
  30
  31  private:
  32   bool traced_;
  33 };
  34
  35 class BasePoint : public GraphPoint {
  36  public:
  37   BasePoint(const clang::CXXBaseSpecifier& spec,
  38             RecordInfo* info,
  39             const TracingStatus& status)
  40       : spec_(spec), info_(info), status_(status) {}
  41   const TracingStatus NeedsTracing() { return status_; }
  42   const clang::CXXBaseSpecifier& spec() { return spec_; }
  43   RecordInfo* info() { return info_; }
  44
  45  private:
  46   const clang::CXXBaseSpecifier& spec_;
  47   RecordInfo* info_;
  48   TracingStatus status_;
  49 };
  50
  51 class FieldPoint : public GraphPoint {
  52  public:
  53   FieldPoint(clang::FieldDecl* field, Edge* edge)
  54       : field_(field), edge_(edge) {}
  55   const TracingStatus NeedsTracing() {
  56     return edge_->NeedsTracing(Edge::kRecursive);
  57   }
  58   clang::FieldDecl* field() { return field_; }
  59   Edge* edge() { return edge_; }
  60
  61  private:
  62   clang::FieldDecl* field_;
  63   Edge* edge_;
  64
  65   friend class RecordCache;
  66   void deleteEdge() { delete edge_; }
  67 };
  68
  69 // Wrapper class to lazily collect information about a C++ record.
  70 class RecordInfo {
  71  public:
  72   typedef std::map<clang::CXXRecordDecl*, BasePoint> Bases;
  73   typedef std::map<clang::FieldDecl*, FieldPoint> Fields;
  74   typedef std::vector<const clang::Type*> TemplateArgs;
  75
  76   ~RecordInfo();
  77
  78   clang::CXXRecordDecl* record() const { return record_; }
  79   const std::string& name() const { return name_; }
  80   Fields& GetFields();
  81   Bases& GetBases();
  82   clang::CXXMethodDecl* GetTraceMethod();
  83   clang::CXXMethodDecl* GetTraceDispatchMethod();
  84   clang::CXXMethodDecl* GetFinalizeDispatchMethod();
  85
  86   bool GetTemplateArgs(size_t count, TemplateArgs* output_args);
  87
  88   bool IsHeapAllocatedCollection();
  89   bool IsGCDerived();
  90   bool IsGCAllocated();
  91   bool IsGCFinalized();
  92   bool IsGCMixin();
  93   bool IsStackAllocated();
  94   bool IsNonNewable();
  95   bool IsOnlyPlacementNewable();
  96   bool IsGCMixinInstance();
  97   clang::CXXMethodDecl* DeclaresNewOperator();
  98
  99   bool RequiresTraceMethod();
 100   bool NeedsFinalization();
 101   bool DeclaresGCMixinMethods();
 102   bool DeclaresLocalTraceMethod();
 103   TracingStatus NeedsTracing(Edge::NeedsTracingOption);
 104   clang::CXXMethodDecl* InheritsNonVirtualTrace();
 105   bool IsConsideredAbstract();
 106
 107   static clang::CXXRecordDecl* GetDependentTemplatedDecl(const clang::Type&);
 108
 109  private:
 110   RecordInfo(clang::CXXRecordDecl* record, RecordCache* cache);
 111
 112   void walkBases();
 113
 114   Fields* CollectFields();
 115   Bases* CollectBases();
 116   void DetermineTracingMethods();
 117   bool InheritsTrace();
 118
 119   Edge* CreateEdge(const clang::Type* type);
 120
 121   RecordCache* cache_;
 122   clang::CXXRecordDecl* record_;
 123   const std::string name_;
 124   TracingStatus fields_need_tracing_;
 125   Bases* bases_;
 126   Fields* fields_;
 127
 128   enum CachedBool { kFalse = 0, kTrue = 1, kNotComputed = 2 };
 129   CachedBool is_stack_allocated_;
 130   CachedBool is_non_newable_;
 131   CachedBool is_only_placement_newable_;
 132   CachedBool does_need_finalization_;
 133   CachedBool has_gc_mixin_methods_;
 134   CachedBool is_declaring_local_trace_;
 135
 136   bool determined_trace_methods_;
 137   clang::CXXMethodDecl* trace_method_;
 138   clang::CXXMethodDecl* trace_dispatch_method_;
 139   clang::CXXMethodDecl* finalize_dispatch_method_;
 140
 141   bool is_gc_derived_;
 142
 143   std::vector<std::string> gc_base_names_;
 144
 145   friend class RecordCache;
 146 };
 147
 148 class RecordCache {
 149  public:
 150   RecordInfo* Lookup(clang::CXXRecordDecl* record);
 151
 152   RecordInfo* Lookup(const clang::CXXRecordDecl* record) {
 153     return Lookup(const_cast<clang::CXXRecordDecl*>(record));
 154   }
 155
 156   RecordInfo* Lookup(clang::DeclContext* decl) {
 157     return Lookup(clang::dyn_cast<clang::CXXRecordDecl>(decl));
 158   }
 159
 160   RecordInfo* Lookup(const clang::Type* type) {
 161     return Lookup(type->getAsCXXRecordDecl());
 162   }
 163
 164   RecordInfo* Lookup(const clang::QualType& type) {
 165     return Lookup(type.getTypePtr());
 166   }
 167
 168   ~RecordCache() {
 169     for (Cache::iterator it = cache_.begin(); it != cache_.end(); ++it) {
 170       if (!it->second.fields_)
 171         continue;
 172       for (RecordInfo::Fields::iterator fit = it->second.fields_->begin();
 173         fit != it->second.fields_->end();
 174         ++fit) {
 175         fit->second.deleteEdge();
 176       }
 177     }
 178   }
 179
 180  private:
 181   typedef std::map<clang::CXXRecordDecl*, RecordInfo> Cache;
 182   Cache cache_;
 183 };
 184
 185 #endif  // TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_