* src/buffer.c (Fgenerate_new_buffer_name): Pacify GCC 7.2.1
20170915 (Red Hat 7.2.1-2) on i686 with -Wformat-overflow -O2 by
using XINT rather than XFASTINT and by adding an eassume. This
works around GCC bug 80776.
* src/fileio.c (Fcopy_file, Frename_file): Tweak the recent change
slightly, as NEWNAME is treated as a directory name depending only
on the contents of the NEWNAME string, and independently of
whether NEWNAME names a directory (i.e., whether the directory
exists) (Bug#29362).
* src/xterm.c (x_draw_window_divider):
* src/w32term.c (w32_draw_window_divider): Fix misbehavior when
drawing three-pixel high horizontal dividers (Bug#29353).
The misbehavior was noted by Keith David Bershatsky and analyzed by Alan
Third.
* src/indent.c (line_number_display_width): Avoid assertion
violations in init_iterator when the window's buffer was
temporarily switched without updating window-start. (Bug#29326)
* configure.ac (HAVE_STRUCT_ATTRIBUTE_ALIGNED): Remove. No longer
needed, since we no longer rely on __attribute__ ((aligned (8))).
All uses removed.
* src/emacs-module.c (HAVE_STRUCT_ATTRIBUTE_ALIGNED): Remove.
(lisp_to_value): Simplify now that we no longer need to worry
whether HAVE_STRUCT_ATTRIBUTE_ALIGNED is false.
Use alignas and unions to specify alignments of objects needing
addresses that are at least a multiple of GCALIGNMENT. Using
these standard C facilities should be safer than relying on ad hoc
and poorly-understood features like GCC’s __attribute__
((aligned (N))), the root cause for recent porting bugs like
Bug#29040. The alignas macro was standardized by C11 and Gnulib
supports alignas for pre-C11 platforms. I have tested this on Sun
Studio 12 sparc (2007) and GCC 4.4.7 x86-64 (2012) as well as on
more recent platforms like GCC 7.2.1 (2017) on Fedora 26 (both
x86-64 and x86).
* lib-src/make-docfile.c (close_emacs_globals): lispsym is now
just an array of struct Lisp_Symbol, since struct Lisp_Symbol is
now properly aligned. All uses changed.
* src/alloc.c (NEXT_FREE_LISP_STRING): Just use the new u.next
member; this is simpler and safer than casting a pointer that
might not be aligned properly.
(aligned_Lisp_Symbol): Remove. No longer needed, now that struct
Lisp_Symbol is aligned properly. All uses replaced with struct
Lisp_Symbol.
* src/lisp.h (GCALIGNED): Remove, as it does not work as expected:
it can cause the natural alignment to be ignored. All uses
replaced by unions with a ‘char alignas (GCALIGNMENT)’ member as
described below.
(struct Lisp_Symbol, struct Lisp_Cons, struct Lisp_String):
Change definition from ‘struct TAG { MEMBERS };’ to
‘struct TAG { union { struct { MEMBERS } s; char alignas
(GCALIGNMENT) gcaligned; } u; };’. This guarantees ‘struct TAG’
to have an alignment that at least max (GCALIGNMENT, N) where N is
its old alignment. All uses like ‘PTR->MEMBER’ changed to
‘PTR->u.s.MEMBER’; these uses were supposed to be mostly private
anyway. Verify that the resulting ‘struct TAG’ is properly
aligned for Emacs.
(union vectorlike_header): New member ‘gcaligned’ to guarantee
that this type, and its containing types like ‘struct Lisp_Subr’,
‘struct buffer’ and ‘struct thread_state’, are all properly
aligned for Emacs.
(struct Lisp_String): New union member ‘next’, for the benefit
of NEXT_FREE_LISP_STRING.
(union Aligned_Cons, union Aligned_String): Remove. All uses
replaced by struct Lisp_Cons and struct Lisp_String, since they
are now properly aligned.
(USE_STACK_CONS, USE_STACK_STRING): Simplify now that we can
assume struct Lisp_Cons and struct Lisp_String are properly
aligned.
* src/lisp.h (vectorlike_headed): Change from struct to union.
All uses changed. Since it has only one member, this does not
change semantics. This is designed to simplify future changes
needed to fix bugs like Bug#29040. All uses changed.
Without these changes, Emacs does not build on Fedora 26 x86-64
when configured --with-x-toolkit=no --enable-gcc-warnings.
* oldXMenu/Activate.c (XMenuActivate): Add FALLTHROUGH.
* src/xterm.c (x_dispatch_event): Define only if
USE_X_TOOLKIT || USE_MOTIF || USE_GTK.
Evidently nobody builds Emacs with --enable-checking=all,
which is no surprise as it is so slow as to be unusable nowadays.
Perhaps we should remove the slowest checks, or move them into
another category, or speed them up, or something.
* src/alloc.c (SDATA_SIZE) [GC_CHECK_STRING_BYTES]: Fix off-by-one
error in size calculation, which caused a failure when
--enable-checking=stringbytes was used. I introduced this bug in
2016-09-08T01:08:45!eggert@cs.ucla.edu "Port flexible array
members to GCC + valgrind".
* src/xdisp.c (should_produce_line_number) [USE_GTK]: Make sure
tip_frame is indeed a tooltip frame, before disabling line numbers
on it. (Bug#27647)
* src/dispextern.h (tip_frame): Add commentary describing the
kludgey usage of this variable in GTK builds.
* src/xdisp.c (try_window_reusing_current_matrix)
(try_cursor_movement): Disallow these optimizations if the buffer
has overlay arrow(s) shown on the fringe(s). (Bug#29198)
Apparently GCC requires that ‘__attribute__ ((aligned (8)))’ must
immediately follow the ‘struct’ keyword when aligning a structure.
The attribute silently does not work if it follows a tag after the
‘struct’ keyword. Who knew? Anyway, this patch is designed to
fix a SIGSEGV problem reported by John Mastro (Bug#29183).
* lib-src/make-docfile.c (close_emacs_globals):
* src/buffer.c (buffer_defaults, buffer_local_symbols):
* src/lisp.h (DEFUN):
* src/thread.c (main_thread):
Put 'GCALIGNED' immediately after 'struct'.
* doc/misc/emacs-gnutls.texi (Help For Users): Update the
documentation of 'gnutls-available-p'.
* etc/NEWS (GnuTLS): Mention the change in the value returned by
'gnutls-available-p'.
* src/gnutls.c (Fgnutls_available_p): Return non-nil when GnuTLS
2.x is available. (Bug#29147)
FreeBSD aarch64 does not provide sbrk, so gmalloc cannot be used; when
using system malloc dumping does not work correctly (allocated data is
invalid after dumping).
* configure.ac: Set hybrid_malloc for freebsd.
* src/gmalloc.c (gdefault_morecore) [!HAVE_SBRK]: Don't call sbrk.
* src/lisp.h (GCALIGNMENT): Change it back to a macro
that expands to a literal integer constant, for older GCC.
I had mistakenly thought that only MSVC had the problem.
Problem repored by Eli Zaretskii (Bug#29040#69).
Do not assume that the natural alignment of Lisp objects is a
multiple of GCALIGNMENT. This improves on the portability of the
recent fix for Bug#29040.
* lib-src/make-docfile.c (close_emacs_globals):
* src/buffer.c (buffer_defaults, buffer_local_symbols):
* src/lisp.h (DEFUN):
* src/thread.c (main_thread):
Use GCALIGNED, not alignas (GCALIGNMENT).
* src/alloc.c (COMMON_MULTIPLE):
Move back here from lisp.h, since it is no longer used elsewhere.
* src/lisp.h (GCALIGNMENT): No longer a macro, since we need not
worry about MSVC. Omit no-longer-needed consistency check.
* src/thread.c (THREAD_ALIGNMENT): Remove.
