[clang-tidy] introduce legacy resource functions to 'cppcoreguidelines-owning-memory'

Summary:
This patch introduces support for legacy C-style resource functions that must obey
the 'owner<>' semantics.

- added legacy creators like malloc,fopen,...
- added legacy consumers like free,fclose,...

This helps codes that mostly benefit from owner:
Legacy, C-Style code that isn't feasable to port directly to RAII but needs a step in between
to identify actual resource management and just using the resources.

Reviewers: aaron.ballman, alexfh, hokein

Reviewed By: aaron.ballman

Subscribers: nemanjai, JDevlieghere, xazax.hun, kbarton

Differential Revision: https://reviews.llvm.org/D38396

llvm-svn: 316092

1 files changed, 61 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/cppcoreguidelines-owning-memory-containers.cpp b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-owning-memory-containers.cpp
new file mode 100644
index 00000000000..929b33d9987
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-owning-memory-containers.cpp
@@ -0,0 +1,61 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-owning-memory %t
+
+namespace gsl {
+template <typename T>
+using owner = T;
+}
+
+namespace std {
+
+// Not actually a vector, but more a dynamic, fixed size array. Just to demonstrate
+// functionality or the lack of the same.
+template <typename T>
+class vector {
+public:
+  vector(unsigned long size, T val) : data{new T[size]}, size{size} {
+    for (unsigned long i = 0ul; i < size; ++i) {
+      data[i] = val;
+    }
+  }
+
+  T *begin() { return data; }
+  T *end() { return &data[size]; }
+  T &operator[](unsigned long index) { return data[index]; }
+
+private:
+  T *data;
+  unsigned long size;
+};
+
+} // namespace std
+
+// All of the following codesnippets should be valid with appropriate 'owner<>' anaylsis,
+// but currently the type information of 'gsl::owner<>' gets lost in typededuction.
+int main() {
+  std::vector<gsl::owner<int *>> OwnerStdVector(100, nullptr);
+
+  // Rangebased looping in resource vector.
+  for (auto *Element : OwnerStdVector) {
+    Element = new int(42);
+    // CHECK-MESSAGES: [[@LINE-1]]:5: warning: assigning newly created 'gsl::owner<>' to non-owner 'int *'
+  }
+  for (auto *Element : OwnerStdVector) {
+    delete Element;
+    // CHECK-MESSAGES: [[@LINE-1]]:5: warning: deleting a pointer through a type that is not marked 'gsl::owner<>'; consider using a smart pointer instead
+    // CHECK-MESSAGES: [[@LINE-3]]:8: note: variable declared here
+  }
+
+  // Indexbased looping in resource vector.
+  for (int i = 0; i < 100; ++i) {
+    OwnerStdVector[i] = new int(42);
+    // CHECK-MESSAGES: [[@LINE-1]]:5: warning: assigning newly created 'gsl::owner<>' to non-owner 'int *'
+  }
+  for (int i = 0; i < 100; ++i) {
+    delete OwnerStdVector[i];
+    // CHECK-MESSAGES: [[@LINE-1]]:5: warning: deleting a pointer through a type that is not marked 'gsl::owner<>'; consider using a smart pointer instead
+    // A note gets emitted here pointing to the return value of the operator[] from the
+    // vector implementation. Maybe this is considered misleading.
+  }
+
+  return 0;
+}