[libc] Introduce a config macro file

libc/src/__support/CPP/bit.h

@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SUPPORT_CPP_BIT_H
 #define LLVM_LIBC_SUPPORT_CPP_BIT_H
 
-#include "src/__support/macros/properties/compiler.h"
+#include "src/__support/macros/config.h" // LIBC_HAS_BUILTIN
 
 namespace __llvm_libc::cpp {
 

libc/src/__support/builtin_wrappers.h

@@ -13,7 +13,7 @@
 #include "named_pair.h"
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/attributes.h"          // LIBC_INLINE
-#include "src/__support/macros/properties/compiler.h" // LIBC_HAS_BUILTIN
+#include "src/__support/macros/config.h"              // LIBC_HAS_BUILTIN
 
 namespace __llvm_libc {
 

libc/src/__support/macros/CMakeLists.txt

@@ -1,5 +1,11 @@
 add_subdirectory(properties)
 
+add_header_library(
+  config
+  HDRS
+    config.h
+)
+
 add_header_library(
   attributes
   HDRS

libc/src/__support/macros/config.h

@@ -0,0 +1,43 @@
+//===-- Portable attributes -------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// This header file defines a set of macros for checking the presence of
+// important compiler and platform features. Such macros can be used to
+// produce portable code by parameterizing compilation based on the presence or
+// lack of a given feature.
+
+#ifndef LLVM_LIBC_SUPPORT_MACROS_CONFIG_H
+#define LLVM_LIBC_SUPPORT_MACROS_CONFIG_H
+
+// LIBC_HAS_BUILTIN()
+//
+// Checks whether the compiler supports a Clang Feature Checking Macro, and if
+// so, checks whether it supports the provided builtin function "x" where x
+// is one of the functions noted in
+// https://clang.llvm.org/docs/LanguageExtensions.html
+//
+// Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
+// http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
+
+
+// Compiler builtin-detection.
+// clang.llvm.org/docs/LanguageExtensions.html#has-builtin
+#ifdef __has_builtin
+#define LIBC_HAS_BUILTIN(x) __has_builtin(x)
+#else
+#define LIBC_HAS_BUILTIN(x) 0
+#endif
+
+// Compiler feature-detection.
+// clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension
+#ifdef __has_feature
+#define LIBC_HAS_FEATURE(f) __has_feature(f)
+#else
+#define LIBC_HAS_FEATURE(f) 0
+#endif
+
+#endif // LLVM_LIBC_SUPPORT_MACROS_CONFIG_H

libc/src/__support/macros/properties/compiler.h

@@ -21,21 +21,4 @@
 #define LIBC_COMPILER_IS_MSC
 #endif
 
-// Compiler builtin-detection.
-// clang.llvm.org/docs/LanguageExtensions.html#has-builtin
-#if defined(LIBC_COMPILER_IS_CLANG) ||                                         \
-    (defined(LIBC_COMPILER_IS_GCC) && (__GNUC__ >= 10))
-#define LIBC_HAS_BUILTIN(BUILTIN) __has_builtin(BUILTIN)
-#else
-#define LIBC_HAS_BUILTIN(BUILTIN) 0
-#endif
-
-// Compiler feature-detection.
-// clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension
-#if defined(LIBC_COMPILER_IS_CLANG)
-#define LIBC_HAS_FEATURE(FEATURE) __has_feature(FEATURE)
-#else
-#define LIBC_HAS_FEATURE(FEATURE) 0
-#endif
-
 #endif // LLVM_LIBC_SUPPORT_MACROS_PROPERTIES_COMPILER_H

libc/src/__support/macros/sanitizer.h

@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_MACROS_SANITIZER_H
 #define LLVM_LIBC_SRC_SUPPORT_MACROS_SANITIZER_H
 
-#include "src/__support/macros/properties/compiler.h"
+#include "src/__support/macros/config.h" //LIBC_HAS_FEATURE
 
 //-----------------------------------------------------------------------------
 // Properties to check the presence or absence or sanitizers

libc/src/string/memory_utils/utils.h

@@ -13,7 +13,7 @@
 #include "src/__support/CPP/cstddef.h"
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/attributes.h"          //LIBC_INLINE
-#include "src/__support/macros/properties/compiler.h" // LIBC_HAS_BUILTIN
+#include "src/__support/macros/config.h"              // LIBC_HAS_BUILTIN
 
 #include <stddef.h> // size_t
 #include <stdint.h> // intptr_t / uintptr_t

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -78,6 +78,12 @@ libc_support_library(
     deps = [":libc_root"],
 )
 
+libc_support_library(
+    name = "__support_macros_config",
+    hdrs = ["src/__support/macros/config.h"],
+    deps = [":libc_root"],
+)
+
 libc_support_library(
     name = "__support_macros_attributes",
     hdrs = ["src/__support/macros/attributes.h"],
@@ -122,7 +128,7 @@ libc_support_library(
     name = "__support_cpp_bit",
     hdrs = ["src/__support/CPP/bit.h"],
     deps = [
-        ":__support_macros_properties_compiler",
+        ":__support_macros_config",
         ":libc_root",
     ],
 )
@@ -303,7 +309,7 @@ libc_support_library(
     deps = [
         ":__support_cpp_type_traits",
         ":__support_macros_attributes",
-        ":__support_macros_properties_compiler",
+        ":__support_macros_config",
         ":__support_named_pair",
         ":libc_root",
     ],