[clang-tidy] Implement type-based check for `gsl::owner`

This check implements the typebased semantic of `gsl::owner`.
Meaning, that 
- only `gsl::owner` is allowed to get `delete`d
- `new` expression must be assigned to `gsl::owner`
- function calls that expect `gsl::owner` as argument, must get either an owner
  or a newly created and recognized resource (in the moment only `new`ed memory)
- assignment to `gsl::owner` must be either a resource or another owner
- functions returning an `gsl::owner` are considered as factories, and their result
  must be assigned to an `gsl::owner`
- classes that have an `gsl::owner`-member must declare a non-default destructor

There are some problems that occur when typededuction is in place.
For example `auto Var = function_that_returns_owner();` the type of `Var` will not be
an `gsl::owner`. This case is catched, and explicitly noted.

But cases like fully templated functions
```
template <typename T> 
void f(T t) { delete t; }
// ...
f(gsl::owner<int*>(new int(42)));
```
Will created false positive (the deletion is problematic), since the type deduction
removes the wrapping `typeAlias`.

Codereview in D36354

llvm-svn: 313067

1 files changed, 44 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h
new file mode 100644
index 00000000000..60c40bc710b
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h
@@ -0,0 +1,44 @@
+//===--- OwningMemoryCheck.h - clang-tidy------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_OWNING_MEMORY_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_OWNING_MEMORY_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+/// Checks for common use cases for gsl::owner and enforces the unique owner
+/// nature of it whenever possible.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-owning-memory.html
+class OwningMemoryCheck : public ClangTidyCheck {
+public:
+  OwningMemoryCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  bool handleDeletion(const ast_matchers::BoundNodes &Nodes);
+  bool handleExpectedOwner(const ast_matchers::BoundNodes &Nodes);
+  bool handleAssignmentAndInit(const ast_matchers::BoundNodes &Nodes);
+  bool handleAssignmentFromNewOwner(const ast_matchers::BoundNodes &Nodes);
+  bool handleReturnValues(const ast_matchers::BoundNodes &Nodes);
+  bool handleOwnerMembers(const ast_matchers::BoundNodes &Nodes);
+};
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_OWNING_MEMORY_H