* Re: Building on MSYS2 fails
2020-08-12 1:06 Building on MSYS2 fails Juanma Barranquero
@ 2020-08-12 1:40 ` Paul Eggert
2020-08-12 9:39 ` Andy Moreton
0 siblings, 1 reply; 3+ messages in thread
From: Paul Eggert @ 2020-08-12 1:40 UTC (permalink / raw)
To: Juanma Barranquero; +Cc: Emacs developers
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On 8/11/20 6:06 PM, Juanma Barranquero wrote:
> CC data.o
> pdumper.c: In function 'dump_read_all':
> pdumper.c:5078:60: error: conversion from 'size_t' {aka 'long long unsigned
> int'} to 'unsigned int' may change value [-Werror=conversion]
Thanks for reporting that. I've had my eye on those -Wconversion false alarms
for some time, and this prompted me to finally get rid of them by installing the
attached patch. Another fix would be to retain -Wconversion in pdumper.c and put
yet another pair of XXX_IMPLICIT_CONVERSION lines into the code, but the cost of
-Wconversion has been less than the benefit for some time, so it's time to omit
-Wconversion here.
[-- Attachment #2: 0001-Don-t-warn-about-integer-conversion-in-pdumper.c.patch --]
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From 38aeb169dbab779fecdda502552a54c90b5344c3 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 11 Aug 2020 18:35:44 -0700
Subject: [PATCH] =?UTF-8?q?Don=E2=80=99t=20warn=20about=20integer=20conver?=
=?UTF-8?q?sion=20in=20pdumper.c?=
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Problem reported by Juanma Barranquero in:
https://lists.gnu.org/r/emacs-devel/2020-08/msg00279.html
and a similar glitch was reported by Eli Zaretskii (Bug#36597#67).
* src/pdumper.c: Remove -Wconversion pragma.
(ALLOW_IMPLICIT_CONVERSION, DISALLOW_IMPLICIT_CONVERSION):
Remove. All uses removed. Although -Wconversion may have
been helpful when writing pdumper.c it is now causing more
trouble than it’s worth here (just as in the rest of Emacs).
(dump_read_all): Avoid no-longer-necessary use of ‘size_t’
rather than ‘int’.
---
src/pdumper.c | 39 +++------------------------------------
1 file changed, 3 insertions(+), 36 deletions(-)
diff --git a/src/pdumper.c b/src/pdumper.c
index 7708bc892f..bc41afc7c5 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -71,17 +71,7 @@
#ifdef HAVE_PDUMPER
#if GNUC_PREREQ (4, 7, 0)
-# pragma GCC diagnostic error "-Wconversion"
-# pragma GCC diagnostic ignored "-Wsign-conversion"
# pragma GCC diagnostic error "-Wshadow"
-# define ALLOW_IMPLICIT_CONVERSION \
- _Pragma ("GCC diagnostic push") \
- _Pragma ("GCC diagnostic ignored \"-Wconversion\"")
-# define DISALLOW_IMPLICIT_CONVERSION \
- _Pragma ("GCC diagnostic pop")
-#else
-# define ALLOW_IMPLICIT_CONVERSION ((void) 0)
-# define DISALLOW_IMPLICIT_CONVERSION ((void) 0)
#endif
#define VM_POSIX 1
@@ -316,9 +306,7 @@ dump_reloc_get_offset (struct dump_reloc reloc)
dump_reloc_set_offset (struct dump_reloc *reloc, dump_off offset)
{
eassert (offset >= 0);
- ALLOW_IMPLICIT_CONVERSION;
reloc->raw_offset = offset >> DUMP_RELOC_ALIGNMENT_BITS;
- DISALLOW_IMPLICIT_CONVERSION;
if (dump_reloc_get_offset (*reloc) != offset)
error ("dump relocation out of range");
}
@@ -744,10 +732,7 @@ dump_off_from_lisp (Lisp_Object value)
{
intmax_t n = intmax_t_from_lisp (value);
eassert (DUMP_OFF_MIN <= n && n <= DUMP_OFF_MAX);
- ALLOW_IMPLICIT_CONVERSION;
- dump_off converted = n;
- DISALLOW_IMPLICIT_CONVERSION;
- return converted;
+ return n;
}
static Lisp_Object
@@ -1994,11 +1979,7 @@ #define START_DUMP_PVEC(ctx, hdr, type, out) \
finish_dump_pvec (struct dump_context *ctx,
union vectorlike_header *out_hdr)
{
- ALLOW_IMPLICIT_CONVERSION;
- dump_off result = dump_object_finish (ctx, out_hdr,
- vectorlike_nbytes (out_hdr));
- DISALLOW_IMPLICIT_CONVERSION;
- return result;
+ return dump_object_finish (ctx, out_hdr, vectorlike_nbytes (out_hdr));
}
static void
@@ -2664,9 +2645,7 @@ hash_table_freeze (struct Lisp_Hash_Table *h)
hash_table_thaw (Lisp_Object hash)
{
struct Lisp_Hash_Table *h = XHASH_TABLE (hash);
- ALLOW_IMPLICIT_CONVERSION;
h->hash = make_nil_vector (XFIXNUM (h->hash));
- DISALLOW_IMPLICIT_CONVERSION;
h->next = Fmake_vector (h->next, make_fixnum (-1));
h->index = Fmake_vector (h->index, make_fixnum (-1));
@@ -3298,9 +3277,7 @@ dump_cold_string (struct dump_context *ctx, Lisp_Object string)
dump_cold_charset (struct dump_context *ctx, Lisp_Object data)
{
/* Dump charset lookup tables. */
- ALLOW_IMPLICIT_CONVERSION;
int cs_i = XFIXNUM (XCAR (data));
- DISALLOW_IMPLICIT_CONVERSION;
dump_off cs_dump_offset = dump_off_from_lisp (XCDR (data));
dump_remember_fixup_ptr_raw
(ctx,
@@ -3608,9 +3585,7 @@ dump_check_overlap_dump_reloc (Lisp_Object lreloc_a,
decode_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
{
struct emacs_reloc reloc = {0};
- ALLOW_IMPLICIT_CONVERSION;
int type = XFIXNUM (dump_pop (&lreloc));
- DISALLOW_IMPLICIT_CONVERSION;
reloc.emacs_offset = dump_off_from_lisp (dump_pop (&lreloc));
dump_check_emacs_off (reloc.emacs_offset);
switch (type)
@@ -3621,9 +3596,7 @@ decode_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
reloc.u.dump_offset = dump_off_from_lisp (dump_pop (&lreloc));
dump_check_dump_off (ctx, reloc.u.dump_offset);
dump_off length = dump_off_from_lisp (dump_pop (&lreloc));
- ALLOW_IMPLICIT_CONVERSION;
reloc.length = length;
- DISALLOW_IMPLICIT_CONVERSION;
if (reloc.length != length)
error ("relocation copy length too large");
}
@@ -3634,9 +3607,7 @@ decode_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
intmax_t value = intmax_t_from_lisp (dump_pop (&lreloc));
dump_off size = dump_off_from_lisp (dump_pop (&lreloc));
reloc.u.immediate = value;
- ALLOW_IMPLICIT_CONVERSION;
reloc.length = size;
- DISALLOW_IMPLICIT_CONVERSION;
eassert (reloc.length == size);
}
break;
@@ -3661,9 +3632,7 @@ decode_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
RELOC_EMACS_IMMEDIATE relocation instead. */
eassert (!dump_object_self_representing_p (target_value));
int tag_type = XTYPE (target_value);
- ALLOW_IMPLICIT_CONVERSION;
reloc.length = tag_type;
- DISALLOW_IMPLICIT_CONVERSION;
eassert (reloc.length == tag_type);
if (type == RELOC_EMACS_EMACS_LV)
@@ -3738,9 +3707,7 @@ dump_merge_emacs_relocs (Lisp_Object lreloc_a, Lisp_Object lreloc_b)
return Qnil;
dump_off new_length = reloc_a.length + reloc_b.length;
- ALLOW_IMPLICIT_CONVERSION;
reloc_a.length = new_length;
- DISALLOW_IMPLICIT_CONVERSION;
if (reloc_a.length != new_length)
return Qnil; /* Overflow */
@@ -5074,7 +5041,7 @@ dump_read_all (int fd, void *buf, size_t bytes_to_read)
/* Some platforms accept only int-sized values to read.
Round this down to a page size (see MAX_RW_COUNT in sysdep.c). */
int max_rw_count = INT_MAX >> 18 << 18;
- size_t chunk_to_read = min (bytes_to_read - bytes_read, max_rw_count);
+ int chunk_to_read = min (bytes_to_read - bytes_read, max_rw_count);
ssize_t chunk = read (fd, (char *) buf + bytes_read, chunk_to_read);
if (chunk < 0)
return chunk;
--
2.17.1
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