build/clang-plugin/MemMoveAnnotation.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef MemMoveAnnotation_h__
   6 #define MemMoveAnnotation_h__
   7
   8 #include "CustomMatchers.h"
   9 #include "CustomTypeAnnotation.h"
  10 #include "Utils.h"
  11
  12 #include <unordered_set>
  13
  14 class MemMoveAnnotation final : public CustomTypeAnnotation {
  15 public:
  16   MemMoveAnnotation()
  17       : CustomTypeAnnotation(moz_non_memmovable, "non-memmove()able") {}
  18
  19   virtual ~MemMoveAnnotation() {}
  20
  21 protected:
  22   std::string getImplicitReason(const TagDecl *D,
  23                                 VisitFlags &ToVisit) const override {
  24     // Annotate everything in ::std, with a few exceptions; see bug
  25     // 1201314 for discussion.
  26     if (getDeclarationNamespace(D) != "std") {
  27       return "";
  28     }
  29
  30     StringRef Name = getNameChecked(D);
  31
  32     // If the type has a trivial move constructor and destructor, it is safe to
  33     // memmove, and we don't need to visit any fields.
  34     auto RD = dyn_cast<CXXRecordDecl>(D);
  35     if (RD && RD->isCompleteDefinition() &&
  36         (RD->hasTrivialMoveConstructor() ||
  37          (!RD->hasMoveConstructor() && RD->hasTrivialCopyConstructor())) &&
  38         RD->hasTrivialDestructor()) {
  39       ToVisit = VISIT_NONE;
  40       return "";
  41     }
  42
  43     // This doesn't check that it's really ::std::pair and not
  44     // ::std::something_else::pair, but should be good enough.
  45     if (isNameExcepted(Name.data())) {
  46       // If we're an excepted name, stop traversing within the type further,
  47       // and only check template arguments for foreign types.
  48       ToVisit = VISIT_TMPL_ARGS;
  49       return "";
  50     }
  51     return "it is an stl-provided type not guaranteed to be memmove-able";
  52   }
  53
  54 private:
  55   bool isNameExcepted(StringRef Name) const {
  56     return Name == "pair" || Name == "atomic" || Name == "tuple";
  57   }
  58 };
  59
  60 extern MemMoveAnnotation NonMemMovable;
  61
  62 #endif