add a bunch of msvc variants

Author: JacobSzwejbka

runtime/platform/compiler.h

@@ -13,140 +13,139 @@
 
 #pragma once
 
-/*
- * Compiler support checks. Follows the logic used by pytorch/c10/util/C++17.h
- * but may support older versions.
- */
+// -----------------------------------------------------------------------------
+// Compiler version checks
+// -----------------------------------------------------------------------------
 
-// https://gcc.gnu.org/projects/cxx-status.html#cxx17
-#if !defined(__clang__) && !defined(_MSC_VER) && defined(__GNUC__) && \
-    __GNUC__ < 7
-#error \
-    "You're trying to build ExecuTorch with a too old version of GCC. We need GCC 7 or later."
+// GCC version check
+#if !defined(__clang__) && !defined(_MSC_VER) && defined(__GNUC__) && __GNUC__ < 7
+#error "You're trying to build ExecuTorch with a too old version of GCC. We need GCC 7 or later."
 #endif
 
-// https://clang.llvm.org/cxx_status.html#cxx17
+// Clang version check
 #if defined(__clang__) && __clang_major__ < 5
-#error \
-    "You're trying to build ExecuTorch with a too old version of Clang. We need Clang 5 or later."
+#error "You're trying to build ExecuTorch with a too old version of Clang. We need Clang 5 or later."
 #endif
 
+// C++17 check
 #if (defined(_MSC_VER) && (!defined(_MSVC_LANG) || _MSVC_LANG < 201703L)) || \
     (!defined(_MSC_VER) && __cplusplus < 201703L)
 #error "You need C++17 to compile ExecuTorch"
 #endif
 
+// Windows min/max macro clash
 #if defined(_MSC_VER) && (defined(min) || defined(max))
-#error \
-    "Macro clash with min and max -- define NOMINMAX when compiling your program on Windows"
+#error "Macro clash with min and max -- define NOMINMAX when compiling your program on Windows"
 #endif
 
-/*
- * Define annotations aliasing C++ declaration attributes.
- * See all C++ declaration attributes here:
- *   https://en.cppreference.com/w/cpp/language/attributes
- *
- * Note that ExecuTorch supports a lower C++ standard version than all standard
- * attributes. Therefore, some annotations are defined using their Clang/GNU
- * counterparts.
- *
- * GNU attribute definitions:
- *   https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html
- */
+// -----------------------------------------------------------------------------
+// Attribute macros
+// -----------------------------------------------------------------------------
 
+// [[noreturn]]
 #define ET_NORETURN [[noreturn]]
+
+// [[deprecated]]
+#define ET_DEPRECATED [[deprecated]]
+#define ET_EXPERIMENTAL [[deprecated("This API is experimental and may change without notice.")]]
+
+// [[fallthrough]]
+#if defined(__clang__) || (defined(__GNUC__) && __GNUC__ >= 7)
+#define ET_FALLTHROUGH [[fallthrough]]
+#else
+#define ET_FALLTHROUGH
+#endif
+
+// [[nodiscard]]
+#define ET_NODISCARD [[nodiscard]]
+
+// [[maybe_unused]]
+#define ET_UNUSED [[maybe_unused]]
+
+// Inline/NoInline
+#if defined(_MSC_VER)
+#define ET_NOINLINE __declspec(noinline)
+#define ET_INLINE __forceinline
+#define ET_INLINE_ATTRIBUTE __forceinline
+#elif defined(__GNUC__) || defined(__clang__)
 #define ET_NOINLINE __attribute__((noinline))
 #define ET_INLINE __attribute__((always_inline)) inline
 #define ET_INLINE_ATTRIBUTE __attribute__((always_inline))
+#else
+#define ET_NOINLINE
+#define ET_INLINE inline
+#define ET_INLINE_ATTRIBUTE
+#endif
 
-#if defined(__GNUC__)
-
+// Unreachable
+#if defined(__GNUC__) || defined(__clang__)
 #define ET_UNREACHABLE() __builtin_unreachable()
-
 #elif defined(_MSC_VER)
-
 #define ET_UNREACHABLE() __assume(0)
+#else
+#define ET_UNREACHABLE() do {} while (1)
+#endif
 
-#else // defined(__GNUC__)
-
-#define ET_UNREACHABLE() \
-  while (1)              \
-    ;
-
-#endif // defined(__GNUC__)
-
-#define ET_DEPRECATED [[deprecated]]
-#define ET_EXPERIMENTAL \
-  [[deprecated("This API is experimental and may change without notice.")]]
-#define ET_FALLTHROUGH [[fallthrough]]
-#define ET_NODISCARD [[nodiscard]]
-#define ET_UNUSED [[maybe_unused]]
-
-// UNLIKELY Macro
-// example
-// if ET_UNLIKELY(a > 10 && b < 5) {
-//   do something
-// }
+// Likely/Unlikely
 #if (__cplusplus) >= 202002L
-
 #define ET_LIKELY(expr) (expr) [[likely]]
 #define ET_UNLIKELY(expr) (expr) [[unlikely]]
-
 #else
-
 #define ET_LIKELY(expr) (expr)
 #define ET_UNLIKELY(expr) (expr)
+#endif
 
-#endif // (__cplusplus) >= 202002L
-
-/// Define a C symbol with weak linkage.
-#ifdef _MSC_VER
-// There currently doesn't seem to be a great way to do this in Windows and
-// given that weak linkage is not really critical on Windows, we'll just leave
-// it as a stub.
+// Weak linkage
+#if defined(_MSC_VER)
+// No weak linkage in MSVC
 #define ET_WEAK
-#else
+#elif defined(__GNUC__) || defined(__clang__)
 #define ET_WEAK __attribute__((weak))
+#else
+#define ET_WEAK
 #endif
 
-/**
- * Annotation marking a function as printf-like, providing compiler support
- * for format string argument checking.
- */
-#ifdef _MSC_VER
+// Printf-like format checking
+#if defined(_MSC_VER)
 #include <sal.h>
 #define ET_PRINTFLIKE(_string_index, _va_index) _Printf_format_string_
-#else
+#elif defined(__GNUC__) || defined(__clang__)
 #define ET_PRINTFLIKE(_string_index, _va_index) \
   __attribute__((format(printf, _string_index, _va_index)))
+#else
+#define ET_PRINTFLIKE(_string_index, _va_index)
 #endif
 
+// -----------------------------------------------------------------------------
+// Builtin/Source location helpers
+// -----------------------------------------------------------------------------
+
 #ifndef __has_builtin
-#define __has_builtin(x) (0)
+#define __has_builtin(x) 0
 #endif
 
 #if __has_builtin(__builtin_strrchr)
-/// Name of the source file without a directory string.
 #define ET_SHORT_FILENAME (__builtin_strrchr("/" __FILE__, '/') + 1)
 #else
 #define ET_SHORT_FILENAME __FILE__
 #endif
 
 #if __has_builtin(__builtin_LINE)
-/// Current line as an integer.
 #define ET_LINE __builtin_LINE()
 #else
 #define ET_LINE __LINE__
-#endif // __has_builtin(__builtin_LINE)
+#endif
 
 #if __has_builtin(__builtin_FUNCTION)
-/// Name of the current function as a const char[].
 #define ET_FUNCTION __builtin_FUNCTION()
 #else
 #define ET_FUNCTION __FUNCTION__
-#endif // __has_builtin(__builtin_FUNCTION)
+#endif
+
+// -----------------------------------------------------------------------------
+// Format specifiers for size_t/ssize_t
+// -----------------------------------------------------------------------------
 
-// As of G3 RJ-2024.3 toolchain, zu format specifier is not supported for Xtensa
 #if defined(__XTENSA__)
 #define ET_PRIsize_t "lu"
 #define ET_PRIssize_t "ld"
@@ -155,24 +154,33 @@
 #define ET_PRIssize_t "zd"
 #endif
 
-// Whether the compiler supports GNU statement expressions.
-// https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
+// -----------------------------------------------------------------------------
+// GNU statement expressions
+// -----------------------------------------------------------------------------
+
 #ifndef ET_HAVE_GNU_STATEMENT_EXPRESSIONS
 #if (defined(__GNUC__) && __GNUC__ >= 3) || defined(__clang__)
 #define ET_HAVE_GNU_STATEMENT_EXPRESSIONS 1
 #else
 #define ET_HAVE_GNU_STATEMENT_EXPRESSIONS 0
 #endif
-#endif // ifndef
+#endif
+
+// -----------------------------------------------------------------------------
+// ssize_t definition
+// -----------------------------------------------------------------------------
 
-// Define size_t and ssize_t.
 #ifndef _MSC_VER
 #include <sys/types.h>
 #else
 #include <stddef.h>
 using ssize_t = ptrdiff_t;
 #endif
 
+// -----------------------------------------------------------------------------
+// Exception support
+// -----------------------------------------------------------------------------
+
 #ifdef __EXCEPTIONS
 #define ET_HAS_EXCEPTIONS 1
 #elif defined(_MSC_VER) && defined(_HAS_EXCEPTIONS) && _HAS_EXCEPTIONS
@@ -181,8 +189,10 @@ using ssize_t = ptrdiff_t;
 #define ET_HAS_EXCEPTIONS 0
 #endif
 
-// DEPRECATED: Use the non-underscore-prefixed versions instead.
-// TODO(T199005537): Remove these once all users have stopped using them.
+// -----------------------------------------------------------------------------
+// Deprecated legacy macros (to be removed)
+// -----------------------------------------------------------------------------
+
 #define __ET_DEPRECATED ET_DEPRECATED
 #define __ET_FALLTHROUGH ET_FALLTHROUGH
 #define __ET_FUNCTION ET_FUNCTION