forked from OSchip/llvm-project
341e825eae
Summary: This attribute specifies expectations about the initialization of static and thread local variables. Specifically that the variable has a [constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization) according to the rules of [basic.start.static]. Failure to meet this expectation will result in an error. Static objects with constant initializers avoid hard-to-find bugs caused by the indeterminate order of dynamic initialization. They can also be safely used by other static constructors across translation units. This attribute acts as a compile time assertion that the requirements for constant initialization have been met. Since these requirements change between dialects and have subtle pitfalls it's important to fail fast instead of silently falling back on dynamic initialization. ```c++ // -std=c++14 #define SAFE_STATIC __attribute__((require_constant_initialization)) static struct T { constexpr T(int) {} ~T(); }; SAFE_STATIC T x = {42}; // OK. SAFE_STATIC T y = 42; // error: variable does not have a constant initializer // copy initialization is not a constant expression on a non-literal type. ``` This attribute can only be applied to objects with static or thread-local storage duration. Reviewers: majnemer, rsmith, aaron.ballman Subscribers: jroelofs, cfe-commits Differential Revision: https://reviews.llvm.org/D23385 llvm-svn: 280525 |
||
|---|---|---|
| .. | ||
| INPUTS | ||
| bindings | ||
| cmake | ||
| docs | ||
| examples | ||
| include | ||
| lib | ||
| runtime | ||
| test | ||
| tools | ||
| unittests | ||
| utils | ||
| www | ||
| .arcconfig | ||
| .clang-format | ||
| .clang-tidy | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| INSTALL.txt | ||
| LICENSE.TXT | ||
| ModuleInfo.txt | ||
| NOTES.txt | ||
| README.txt | ||
README.txt
//===----------------------------------------------------------------------===// // C Language Family Front-end //===----------------------------------------------------------------------===// Welcome to Clang. This is a compiler front-end for the C family of languages (C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM compiler infrastructure project. Unlike many other compiler frontends, Clang is useful for a number of things beyond just compiling code: we intend for Clang to be host to a number of different source-level tools. One example of this is the Clang Static Analyzer. If you're interested in more (including how to build Clang) it is best to read the relevant web sites. Here are some pointers: Information on Clang: http://clang.llvm.org/ Building and using Clang: http://clang.llvm.org/get_started.html Clang Static Analyzer: http://clang-analyzer.llvm.org/ Information on the LLVM project: http://llvm.org/ If you have questions or comments about Clang, a great place to discuss them is on the Clang development mailing list: http://lists.llvm.org/mailman/listinfo/cfe-dev If you find a bug in Clang, please file it in the LLVM bug tracker: http://llvm.org/bugs/