On 3/2/21 7:09 PM, Bruno Haible wrote:
+ /* On TinyCC, make sure that the macros that indicate the special invocation
+ convention get undefined. */
+# ifdef __TINYC__
+# undef __need_wchar_t
+# undef __need_size_t
Would it be more robust to omit the "#ifdef __TINYC__" line, and
unconditionally undef those macros? That won't hurt GCC, and it should
help with any compiler (not just tcc) that is incompatible with GCC in
this respect.
Also, test-stdalign failed on Ubuntu 20.10 with tcc, since tcc's
<stdalign.h> has a broken alignof when glibc headers like <stdint.h> are
used. Glibc <stdint.h> defines __attribute__(x) to empty for compilers
like tcc that do not define __GNUC__, but tcc's alignof relies on
__attribute__. I installed the attached patch to try to work around that
problem.
From 7955dc93ef02c0cb90a8c4966abf142a3813ff48 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Thu, 4 Mar 2021 00:47:19 -0800
Subject: [PATCH] stdalign: port to tcc + glibc
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
* lib/stdalign.in.h (_Alignas): Do not define using __attribute__
if __attribute__ is defined as a macro, as __attribute__ surely a
no-op in that case and this is an area where __attribute__ cannot
simply be ignored.
* m4/stdalign.m4 (gl_STDALIGN_H): Include <stdint.h> so that
it #defines __attribute__(x) to nothing on glibc-based systems
when non-GNU-C-compatible compilers are used.
This exposes a bug in Tiny C Compiler 0.9.27’s implementation
of _Alignas on glibc platforms.
---
ChangeLog | 13 +++++++++++++
lib/stdalign.in.h | 13 +++++++------
m4/stdalign.m4 | 4 +++-
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 9f6818c17..50d247fac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2021-03-04 Paul Eggert <egg...@cs.ucla.edu>
+
+ stdalign: port to tcc + glibc
+ * lib/stdalign.in.h (_Alignas): Do not define using __attribute__
+ if __attribute__ is defined as a macro, as __attribute__ surely a
+ no-op in that case and this is an area where __attribute__ cannot
+ simply be ignored.
+ * m4/stdalign.m4 (gl_STDALIGN_H): Include <stdint.h> so that
+ it #defines __attribute__(x) to nothing on glibc-based systems
+ when non-GNU-C-compatible compilers are used.
+ This exposes a bug in Tiny C Compiler 0.9.27’s implementation
+ of _Alignas on glibc platforms.
+
2021-03-03 Bruno Haible <br...@clisp.org>
asyncsafe-spin, simple-atomic: Add support for tcc/x86.
diff --git a/lib/stdalign.in.h b/lib/stdalign.in.h
index e7a7402ee..52a4a7b6e 100644
--- a/lib/stdalign.in.h
+++ b/lib/stdalign.in.h
@@ -104,12 +104,13 @@
#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
# if defined __cplusplus && 201103 <= __cplusplus
# define _Alignas(a) alignas (a)
-# elif ((defined __APPLE__ && defined __MACH__ \
- ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
- : __GNUC__ && !defined __ibmxl__) \
- || (4 <= __clang_major__) \
- || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
- || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__)
+# elif (!defined __attribute__ \
+ && ((defined __APPLE__ && defined __MACH__ \
+ ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+ : __GNUC__ && !defined __ibmxl__) \
+ || (4 <= __clang_major__) \
+ || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+ || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__))
# define _Alignas(a) __attribute__ ((__aligned__ (a)))
# elif 1300 <= _MSC_VER
# define _Alignas(a) __declspec (align (a))
diff --git a/m4/stdalign.m4 b/m4/stdalign.m4
index 8dcb634d5..e22d7f78c 100644
--- a/m4/stdalign.m4
+++ b/m4/stdalign.m4
@@ -13,7 +13,8 @@ AC_DEFUN([gl_STDALIGN_H],
[gl_cv_header_working_stdalign_h],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
- [[#include <stdalign.h>
+ [[#include <stdint.h>
+ #include <stdalign.h>
#include <stddef.h>
/* Test that alignof yields a result consistent with offsetof.
@@ -32,6 +33,7 @@ AC_DEFUN([gl_STDALIGN_H],
/* Test _Alignas only on platforms where gnulib can help. */
#if \
((defined __cplusplus && 201103 <= __cplusplus) \
+ || (__TINYC__ && defined __attribute__) \
|| (defined __APPLE__ && defined __MACH__ \
? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
: __GNUC__) \
--
2.27.0
