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   void MarkTraced() { traced_ = true; }
  27   bool IsProperlyTraced() { return traced_ || !NeedsTracing().IsNeeded(); }
  28   virtual const TracingStatus NeedsTracing() = 0;
  29
  30  private:
  31   bool traced_;
  32 };
  33
  34 class BasePoint : public GraphPoint {
  35  public:
  36   BasePoint(const clang::CXXBaseSpecifier& spec,
  37             RecordInfo* info,
  38             const TracingStatus& status)
  39       : spec_(spec), info_(info), status_(status) {}
  40   const TracingStatus NeedsTracing() { return status_; }
  41   const clang::CXXBaseSpecifier& spec() { return spec_; }
  42   RecordInfo* info() { return info_; }
  43
  44  private:
  45   const clang::CXXBaseSpecifier& spec_;
  46   RecordInfo* info_;
  47   TracingStatus status_;
  48 };
  49
  50 class FieldPoint : public GraphPoint {
  51  public:
  52   FieldPoint(clang::FieldDecl* field, Edge* edge)
  53       : field_(field), edge_(edge) {}
  54   const TracingStatus NeedsTracing() {
  55     return edge_->NeedsTracing(Edge::kRecursive);
  56   }
  57   clang::FieldDecl* field() { return field_; }
  58   Edge* edge() { return edge_; }
  59
  60  private:
  61   clang::FieldDecl* field_;
  62   Edge* edge_;
  63
  64   friend class RecordCache;
  65   void deleteEdge() { delete edge_; }
  66 };
  67
  68 // Wrapper class to lazily collect information about a C++ record.
  69 class RecordInfo {
  70  public:
  71   typedef std::map<clang::CXXRecordDecl*, BasePoint> Bases;
  72   typedef std::map<clang::FieldDecl*, FieldPoint> Fields;
  73   typedef std::vector<const clang::Type*> TemplateArgs;
  74
  75   ~RecordInfo();
  76
  77   clang::CXXRecordDecl* record() const { return record_; }
  78   const std::string& name() const { return name_; }
  79   Fields& GetFields();
  80   Bases& GetBases();
  81   clang::CXXMethodDecl* GetTraceMethod();
  82   clang::CXXMethodDecl* GetTraceDispatchMethod();
  83   clang::CXXMethodDecl* GetFinalizeDispatchMethod();
  84
  85   bool GetTemplateArgs(size_t count, TemplateArgs* output_args);
  86
  87   bool IsHeapAllocatedCollection();
  88   bool IsGCDerived();
  89   bool IsGCAllocated();
  90   bool IsGCFinalized();
  91   bool IsGCMixin();
  92   bool IsStackAllocated();
  93   bool IsNonNewable();
  94   bool IsOnlyPlacementNewable();
  95   bool IsGCMixinInstance();
  96   clang::CXXMethodDecl* DeclaresNewOperator();
  97
  98   bool RequiresTraceMethod();
  99   bool NeedsFinalization();
 100   bool DeclaresGCMixinMethods();
 101   bool DeclaresLocalTraceMethod();
 102   TracingStatus NeedsTracing(Edge::NeedsTracingOption);
 103   clang::CXXMethodDecl* InheritsNonVirtualTrace();
 104   bool IsConsideredAbstract();
 105
 106   static clang::CXXRecordDecl* GetDependentTemplatedDecl(const clang::Type&);
 107
 108  private:
 109   RecordInfo(clang::CXXRecordDecl* record, RecordCache* cache);
 110
 111   void walkBases();
 112
 113   Fields* CollectFields();
 114   Bases* CollectBases();
 115   void DetermineTracingMethods();
 116   bool InheritsTrace();
 117
 118   Edge* CreateEdge(const clang::Type* type);
 119
 120   RecordCache* cache_;
 121   clang::CXXRecordDecl* record_;
 122   const std::string name_;
 123   TracingStatus fields_need_tracing_;
 124   Bases* bases_;
 125   Fields* fields_;
 126
 127   enum CachedBool { kFalse = 0, kTrue = 1, kNotComputed = 2 };
 128   CachedBool is_stack_allocated_;
 129   CachedBool is_non_newable_;
 130   CachedBool is_only_placement_newable_;
 131   CachedBool does_need_finalization_;
 132   CachedBool has_gc_mixin_methods_;
 133   CachedBool is_declaring_local_trace_;
 134
 135   bool determined_trace_methods_;
 136   clang::CXXMethodDecl* trace_method_;
 137   clang::CXXMethodDecl* trace_dispatch_method_;
 138   clang::CXXMethodDecl* finalize_dispatch_method_;
 139
 140   bool is_gc_derived_;
 141
 142   std::vector<std::string> gc_base_names_;
 143
 144   friend class RecordCache;
 145 };
 146
 147 class RecordCache {
 148  public:
 149   RecordInfo* Lookup(clang::CXXRecordDecl* record);
 150
 151   RecordInfo* Lookup(const clang::CXXRecordDecl* record) {
 152     return Lookup(const_cast<clang::CXXRecordDecl*>(record));
 153   }
 154
 155   RecordInfo* Lookup(clang::DeclContext* decl) {
 156     return Lookup(clang::dyn_cast<clang::CXXRecordDecl>(decl));
 157   }
 158
 159   RecordInfo* Lookup(const clang::Type* type) {
 160     return Lookup(type->getAsCXXRecordDecl());
 161   }
 162
 163   RecordInfo* Lookup(const clang::QualType& type) {
 164     return Lookup(type.getTypePtr());
 165   }
 166
 167   ~RecordCache() {
 168     for (Cache::iterator it = cache_.begin(); it != cache_.end(); ++it) {
 169       if (!it->second.fields_)
 170         continue;
 171       for (RecordInfo::Fields::iterator fit = it->second.fields_->begin();
 172         fit != it->second.fields_->end();
 173         ++fit) {
 174         fit->second.deleteEdge();
 175       }
 176     }
 177   }
 178
 179  private:
 180   typedef std::map<clang::CXXRecordDecl*, RecordInfo> Cache;
 181   Cache cache_;
 182 };
 183
 184 #endif  // TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_