On 3/24/20 10:18 AM, Jakub Jelinek wrote:
Hi!
So, assuming I'm on glibc with GCC 4.5 on powerpc64-linux.
On Tue, Mar 24, 2020 at 09:49:42AM +0100, Martin Liška wrote:
+/* Detect endianess based on __BYTE_ORDER__ macro. */
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
+ defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_PDP_ENDIAN__)
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define PLUGIN_LITTLE_ENDIAN 1
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define PLUGIN_BIG_ENDIAN 1
+#elif __BYTE_ORDER__ == __ORDER_PDP_ENDIAN__
+#define PLUGIN_PDP_ENDIAN 1
+#endif
+#else
+/* Older GCC releases (<4.6.0) can make detection from glibc macros. */
+#if defined(__GLIBC__) || defined(__GNU_LIBRARY__) || defined(__ANDROID__)
+#include <endian.h>
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define PLUGIN_LITTLE_ENDIAN 1
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define PLUGIN_BIG_ENDIAN 1
+#endif
This will definePLUGIN_BIG_ENDIAN.
+#endif
+/* Include all necessary header files based on target. */
+#if defined(__SVR4) && defined(__sun)
+#include <sys/byteorder.h>
+#endif
+#if defined(__FreeBSD__) || defined(__NetBSD__) || \
+ defined(__DragonFly__) || defined(__minix)
+#include <sys/endian.h>
+#endif
+#if defined(__OpenBSD__)
+#include <machine/endian.h>
+#endif
The above headers will not be included.
+/* Detect endianess based on _BYTE_ORDER. */
+#if _BYTE_ORDER == _LITTLE_ENDIAN
So most likely _BYTE_ORDER and _LITTLE_ENDIAN macros will not be defined.
Which means this will be handled as #if 0 == 0 and override the
+#define PLUGIN_LITTLE_ENDIAN 1
will define also PLUGIN_LITTLE_ENDIAN.
Ok, for being sure, I've wrapped all equality comparison with corresponding
check of the LHS is defined.
+#elif _BYTE_ORDER == _BIG_ENDIAN
+#define PLUGIN_BIG_ENDIAN 1
+#endif
+/* Detect based on _WIN32. */
+#if defined(_WIN32)
+#define PLUGIN_LITTLE_ENDIAN 1
+#endif
+/* Fallback to __BIG_ENDIAN__ and __LITTLE_ENDIAN__ */
+#ifdef __LITTLE_ENDIAN__
+#define PLUGIN_LITTLE_ENDIAN 1
+#endif
+#ifdef __BIG_ENDIAN__
+#define PLUGIN_BIG_ENDIAN 1
+#endif
+#endif
and the above isn't really a fallback, because it isn't guarded with
PLUGIN_*_ENDIAN not being defined yet.
This comment has been also updated.
Martin
Jakub
>From 82b8731f304c734353c34ddaf1b1265341a90882 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Tue, 24 Mar 2020 09:12:50 +0100
Subject: [PATCH] Improve endianess detection.
include/ChangeLog:
2020-03-24 Martin Liska <mli...@suse.cz>
PR lto/94249
* plugin-api.h: Add more robust endianess detection.
---
include/plugin-api.h | 65 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 63 insertions(+), 2 deletions(-)
diff --git a/include/plugin-api.h b/include/plugin-api.h
index 673f136ce68..864d2bf91ac 100644
--- a/include/plugin-api.h
+++ b/include/plugin-api.h
@@ -37,6 +37,60 @@
#error cannot find uint64_t type
#endif
+/* Detect endianess based on __BYTE_ORDER__ macro. */
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
+ defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_PDP_ENDIAN__)
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define PLUGIN_LITTLE_ENDIAN 1
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define PLUGIN_BIG_ENDIAN 1
+#elif __BYTE_ORDER__ == __ORDER_PDP_ENDIAN__
+#define PLUGIN_PDP_ENDIAN 1
+#endif
+#else
+/* Older GCC releases (<4.6.0) can make detection from glibc macros. */
+#if defined(__GLIBC__) || defined(__GNU_LIBRARY__) || defined(__ANDROID__)
+#include <endian.h>
+#ifdef _BYTE_ORDER
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define PLUGIN_LITTLE_ENDIAN 1
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define PLUGIN_BIG_ENDIAN 1
+#endif
+#endif
+#endif
+/* Include all necessary header files based on target. */
+#if defined(__SVR4) && defined(__sun)
+#include <sys/byteorder.h>
+#endif
+#if defined(__FreeBSD__) || defined(__NetBSD__) || \
+ defined(__DragonFly__) || defined(__minix)
+#include <sys/endian.h>
+#endif
+#if defined(__OpenBSD__)
+#include <machine/endian.h>
+#endif
+/* Detect endianess based on _BYTE_ORDER. */
+#ifdef _BYTE_ORDER
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+#define PLUGIN_LITTLE_ENDIAN 1
+#elif _BYTE_ORDER == _BIG_ENDIAN
+#define PLUGIN_BIG_ENDIAN 1
+#endif
+#endif
+/* Detect based on _WIN32. */
+#if defined(_WIN32)
+#define PLUGIN_LITTLE_ENDIAN 1
+#endif
+/* Detect based on __BIG_ENDIAN__ and __LITTLE_ENDIAN__ */
+#ifdef __LITTLE_ENDIAN__
+#define PLUGIN_LITTLE_ENDIAN 1
+#endif
+#ifdef __BIG_ENDIAN__
+#define PLUGIN_BIG_ENDIAN 1
+#endif
+#endif
+
#ifdef __cplusplus
extern "C"
{
@@ -89,16 +143,23 @@ struct ld_plugin_symbol
char *version;
/* This is for compatibility with older ABIs. The older ABI defined
only 'def' field. */
-#ifdef __BIG_ENDIAN__
+#if PLUGIN_BIG_ENDIAN == 1
char unused;
char section_kind;
char symbol_type;
char def;
-#else
+#elif PLUGIN_LITTLE_ENDIAN == 1
char def;
char symbol_type;
char section_kind;
char unused;
+#elif PLUGIN_PDP_ENDIAN == 1
+ char symbol_type;
+ char def;
+ char unused;
+ char section_kind;
+#else
+#error "Could not detect architecture endianess"
#endif
int visibility;
uint64_t size;
--
2.25.1
