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1 // Copyright (c) 2010 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 // Clang plugin which finds types that are affected if the types listed in the
6 // plugin parameters are changed.  This is for use in determining what PPAPI
7 // C-level interfaces are affected if one or more PPAPI C structs are changed.
8 
9 #include <algorithm>
10 #include <cstdio>
11 #include <map>
12 #include <sstream>
13 #include <string>
14 #include <vector>
15 
16 #include "clang/AST/AST.h"
17 #include "clang/AST/ASTConsumer.h"
18 #include "clang/AST/CharUnits.h"
19 #include "clang/Basic/SourceManager.h"
20 #include "clang/Basic/TargetInfo.h"
21 #include "clang/Frontend/CompilerInstance.h"
22 #include "clang/Frontend/FrontendPluginRegistry.h"
23 
24 namespace {
25 
26 typedef std::vector<std::string> StringVec;
27 
28 class FindAffectedInterfacesConsumer : public clang::ASTConsumer {
29  public:
FindAffectedInterfacesConsumer(const StringVec & changed_classes)30   explicit FindAffectedInterfacesConsumer(const StringVec& changed_classes) {
31     StringVec::const_iterator iter(changed_classes.begin());
32     StringVec::const_iterator the_end(changed_classes.end());
33     for (; iter != the_end; ++iter) {
34       class_is_affected_map_[*iter] = true;
35     }
36   }
37 
38  private:
39   typedef std::map<std::string, bool> StringBoolMap;
40   StringBoolMap class_is_affected_map_;
41 
IsAffected(const clang::Type & type_to_check)42   bool IsAffected(const clang::Type& type_to_check) {
43     std::string type_string(
44       type_to_check.getCanonicalTypeInternal().getAsString());
45     std::pair<StringBoolMap::iterator, bool> iter_success_pair =
46         class_is_affected_map_.insert(
47             StringBoolMap::value_type(type_string, false));
48     StringBoolMap::iterator iter(iter_success_pair.first);
49     bool successfully_inserted(iter_success_pair.second);
50     // If we were able to insert, then we haven't yet seen this type.  Compute
51     // IsAffected and put it at the newly inserted location in the map.
52     if (successfully_inserted) {
53       if (type_to_check.isPointerType()) {
54         const clang::PointerType* pointer_type =
55             dyn_cast<clang::PointerType>(&type_to_check);
56         // Recurse to the pointee type.
57         iter->second = IsAffected(*pointer_type->getPointeeType().getTypePtr());
58       } else if (type_to_check.isFunctionProtoType()) {
59         const clang::FunctionProtoType* func_type =
60             dyn_cast<clang::FunctionProtoType>(&type_to_check);
61         // Recurse to the return type and parameter types.
62         iter->second = IsAffected(*func_type->getResultType().getTypePtr());
63         if (!iter->second) {
64           clang::FunctionProtoType::arg_type_iterator arg_iter =
65               func_type->arg_type_begin();
66           clang::FunctionProtoType::arg_type_iterator arg_end =
67               func_type->arg_type_end();
68           for (; (arg_iter != arg_end) && (!iter->second); ++arg_iter) {
69             iter->second = IsAffected(*(arg_iter->getTypePtr()));
70           }
71         }
72       } else if (type_to_check.isRecordType()) {
73         // For records (unions, structs), recurse to the fields.
74         const clang::RecordType* record =
75             dyn_cast<clang::RecordType>(&type_to_check);
76         const clang::RecordDecl* decl = record->getDecl();
77         clang::RecordDecl::field_iterator field_iter(decl->field_begin());
78         clang::RecordDecl::field_iterator field_end(decl->field_end());
79         for (; (field_iter != field_end) && (!iter->second); ++field_iter) {
80           iter->second = IsAffected(*(field_iter->getType().getTypePtr()));
81         }
82       }
83     }
84     // By this point, the bool in the map at the location referenced by iter has
85     // the correct value.  Either it was cached, or we computed & inserted it.
86     return iter->second;
87   }
88 
89   // Virtual function to consume top-level declarations.  For each one, we check
90   // to see if it is a type definition.  If it is, we print information about
91   // it.
HandleTopLevelDecl(clang::DeclGroupRef decl_group)92   virtual void HandleTopLevelDecl(clang::DeclGroupRef decl_group) {
93     clang::DeclGroupRef::iterator iter(decl_group.begin());
94     clang::DeclGroupRef::iterator the_end(decl_group.end());
95     for (; iter != the_end; ++iter) {
96       const clang::Decl *decl = *iter;
97       if (const clang::TypeDecl* type_decl = dyn_cast<clang::TypeDecl>(decl)) {
98         std::string name(type_decl->getNameAsString());
99         // TagDecl covers structs, enums, unions, and classes.
100         if (const clang::TagDecl* tag = dyn_cast<clang::TagDecl>(type_decl)) {
101           // Only print out info when we find the definition;  ignore forward
102           // references.
103           if (tag->isDefinition()) {
104             clang::Type* type = type_decl->getTypeForDecl();
105             if (IsAffected(*type)) {
106               std::printf("%s\n", name.c_str());
107             }
108           }
109         } else if (const clang::TypedefDecl* td =
110                    dyn_cast<clang::TypedefDecl>(type_decl)) {
111           clang::Type* type = td->getUnderlyingType().getTypePtr();
112           if (IsAffected(*type)) {
113             std::printf("%s\n", name.c_str());
114           }
115         }
116       }
117     }
118   }
119 };
120 
121 class FindAffectedInterfacesAction : public clang::PluginASTAction {
122  public:
FindAffectedInterfacesAction()123   FindAffectedInterfacesAction() {}
124 
125  private:
126   StringVec types_;
127 
CreateASTConsumer(clang::CompilerInstance & instance,llvm::StringRef)128   virtual clang::ASTConsumer *CreateASTConsumer(
129       clang::CompilerInstance &instance, llvm::StringRef /*input_file*/) {
130     return new FindAffectedInterfacesConsumer(types_);
131   }
132 
ParseArgs(const clang::CompilerInstance &,const std::vector<std::string> & args)133   virtual bool ParseArgs(const clang::CompilerInstance& /*instance*/,
134                          const std::vector<std::string>& args) {
135     // Every argument is interpreted as a comma-delimited list of names of types
136     // that have been changed.
137     StringVec::const_iterator iter(args.begin()), end(args.end());
138     for (; iter != end; ++iter) {
139       std::stringstream stream(*iter);
140       std::string type_name;
141       while (std::getline(stream, type_name, ',')) {
142         types_.push_back(type_name);
143       }
144     }
145     return true;
146   }
147 };
148 
149 }  // namespace
150 
151 static clang::FrontendPluginRegistry::Add<FindAffectedInterfacesAction>
152 X("FindAffectedInterfaces",
153   "Find interfaces affected by changes to the passes classes.");
154 
155