68 lines
2.8 KiB
ReStructuredText
68 lines
2.8 KiB
ReStructuredText
.. _code_style:
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===================
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The libc code style
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===================
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Naming style
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============
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For the large part, the libc project follows the general `coding standards of
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the LLVM project <https://llvm.org/docs/CodingStandards.html>`_. The libc
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project differs from that standard with respect to the naming style. The
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differences are as follows:
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#. **Non-const variables** - This includes function arguments, struct and
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class data members, non-const globals and local variables. They all use the
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``snake_case`` style.
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#. **const and constexpr variables** - They use the capitlized
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``SNAKE_CASE`` irrespective of whether they are local or global.
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#. **Function and methods** - They use the ``snake_case`` style like the
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non-const variables.
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#. **Internal type names** - These are types which are interal to the libc
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implementation. They use the ``CaptilizedCamelCase`` style.
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#. **Public names** - These are the names as prescribed by the standards and
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will follow the style as prescribed by the standards.
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Macro style
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===========
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We define two kinds of macros: **code defined** and **build defined** macros.
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#. **Build defined** macros are generated by `CMake` or `Bazel` and are passed
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down to the compiler with the ``-D`` command line flag. They start with the
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``LIBC_COPT_`` prefix. They are used to tune the behavior of the libc.
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They either denote an action or define a constant.
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#. **Code defined** macros are defined within the ``src/__support/macros``
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folder. They all start with the ``LIBC_`` prefix. They are of two kinds
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* **Properties** - Build related properties like used compiler, target
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architecture or enabled CPU features defined by introspecting compiler
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defined preprocessor defininitions. e.g., ``LIBC_TARGET_ARCH_IS_ARM``,
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``LIBC_TARGET_CPU_HAS_AVX2``, ``LIBC_COMPILER_IS_CLANG``, ...
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* **Attributes** - Compiler agnostic attributes or functions to handle
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specific operations. e.g., ``LIBC_INLINE``, ``LIBC_NO_LOOP_UNROLL``,
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``LIBC_LIKELY``, ``LIBC_INLINE_ASM``.
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Inline functions defined in header files
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========================================
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When defining functions inline in header files, we follow certain rules:
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#. The functions should not be given file-static linkage. There can be class
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static methods defined inline however.
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#. Instead of using the ``inline`` keyword, they should be tagged with the
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``LIBC_INLINE`` macro defined in ``src/__support/common.h``. For example:
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.. code-block:: c++
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LIBC_INLINE ReturnType function_defined_inline(ArgType arg) {
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...
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}
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#. The ``LIBC_INLINE`` tag should also be added to functions which have
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definitions that are implicitly inline. Examples of such functions are
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class methods (static and non-static) defined inline and ``constexpr``
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functions.
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