[libc-commits] [libc] [libc] implement endian related macros (PR #126368)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: None (c8ef)

<details>
<summary>Changes</summary>

Follow up of #<!-- -->125168.

This patch adds endian-related macros to `endian.h`. We utilize compiler built-ins for byte swap functions, which are already included in our minimal supported compiler version.

---
Full diff: https://github.com/llvm/llvm-project/pull/126368.diff


2 Files Affected:

- (modified) libc/include/llvm-libc-macros/CMakeLists.txt (+2) 
- (modified) libc/include/llvm-libc-macros/endian-macros.h (+34) 


``````````diff
diff --git a/libc/include/llvm-libc-macros/CMakeLists.txt b/libc/include/llvm-libc-macros/CMakeLists.txt
index ea892a87dbe7ab9..6124fd136ce6d0c 100644
--- a/libc/include/llvm-libc-macros/CMakeLists.txt
+++ b/libc/include/llvm-libc-macros/CMakeLists.txt
@@ -314,6 +314,8 @@ add_macro_header(
   endian_macros
   HDR
     endian-macros.h
+  DEPENDS
+    .stdint_macros
 )
 
 add_macro_header(
diff --git a/libc/include/llvm-libc-macros/endian-macros.h b/libc/include/llvm-libc-macros/endian-macros.h
index 94e1d60f8ff404f..e1e105d50c1c68a 100644
--- a/libc/include/llvm-libc-macros/endian-macros.h
+++ b/libc/include/llvm-libc-macros/endian-macros.h
@@ -9,8 +9,42 @@
 #ifndef LLVM_LIBC_MACROS_ENDIAN_MACROS_H
 #define LLVM_LIBC_MACROS_ENDIAN_MACROS_H
 
+#include "stdint-macros.h"
+
 #define LITTLE_ENDIAN __ORDER_LITTLE_ENDIAN__
 #define BIG_ENDIAN __ORDER_BIG_ENDIAN__
 #define BYTE_ORDER __BYTE_ORDER__
 
+#if BYTE_ORDER == LITTLE_ENDIAN
+
+#define htobe16(x) __builtin_bswap16((x))
+#define htobe32(x) __builtin_bswap32((x))
+#define htobe64(x) __builtin_bswap64((x))
+#define htole16(x) ((uint16_t)(x))
+#define htole32(x) ((uint32_t)(x))
+#define htole64(x) ((uint64_t)(x))
+#define be16toh(x) __builtin_bswap16((x))
+#define be32toh(x) __builtin_bswap32((x))
+#define be64toh(x) __builtin_bswap64((x))
+#define le16toh(x) ((uint16_t)(x))
+#define le32toh(x) ((uint32_t)(x))
+#define le64toh(x) ((uint64_t)(x))
+
+#else
+
+#define htobe16(x) ((uint16_t)(x))
+#define htobe32(x) ((uint32_t)(x))
+#define htobe64(x) ((uint64_t)(x))
+#define htole16(x) __builtin_bswap16((x))
+#define htole32(x) __builtin_bswap32((x))
+#define htole64(x) __builtin_bswap64((x))
+#define be16toh(x) ((uint16_t)(x))
+#define be32toh(x) ((uint32_t)(x))
+#define be64toh(x) ((uint64_t)(x))
+#define le16toh(x) __builtin_bswap16((x))
+#define le32toh(x) __builtin_bswap32((x))
+#define le64toh(x) __builtin_bswap64((x))
+
+#endif
+
 #endif // LLVM_LIBC_MACROS_ENDIAN_MACROS_H

``````````

</details>


https://github.com/llvm/llvm-project/pull/126368