Fix regcomp.c build for 32-bit with GCC mainline

[Paul Eggert]

On 11/20/2017 03:18 PM, Joseph Myers wrote:
> On Mon, 20 Nov 2017, Adhemerval Zanella wrote:
>
>> Why not use the already upstream fix from gnulib
>> (252b52457da7887667c036d18cc5169777615bb0) ?
> That change would not apply cleanly to current sources,

That should be easy enough to fix. Proposed patch attached.

> and if we have
> over five years of regex changes out of sync with gnulib, it doesn't seem
> a good idea to try to tie any possible resync with gnulib (in both
> directions) to fixing build failures to make it possible to detect build
> regressions when they occur (rather than piling one failure on top of
> another that isn't yet fixed, so making it hard to determine the
> problematic patch, which is the current state).

Although I didn't quite follow all that, I vaguely took it to mean "it's 
too much trouble to try to keep glibc regex code close to Gnulib". But 
if someone has taken the trouble to keep them closer (as in the attached 
patch) then we might as well keep them as close as we reasonably can. On 
the Gnulib side I've been trying to do that by merging glibc's changes, 
as in the patch I installed into Gnulib today:

https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=6dc8556f97cf3e7953249190b46465ad845761cf
-------------- next part --------------
From 99a25c4defd9ff20c9592d999c5ff2e932c22008 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 20 Nov 2017 16:25:49 -0800
Subject: [PATCH] regex: don't assume uint64_t or uint32_t

This avoids -Werror=overflow errors for 32-bit systems in
the 64-bit case.  Problem reported by Joseph Myers in:
https://sourceware.org/ml/libc-alpha/2017-11/msg00694.html
Also, when this code is used in Gnulib it ports to platforms
that lack uint64_t and uint32_t.  The C standard doesn't guarantee
them, and on some 32-bit compilers there is no uint64_t.
Problem reported by Gianluigi Tiesi in:
http://lists.gnu.org/archive/html/bug-gnulib/2012-03/msg00154.html
* posix/regcomp.c (init_word_char): Don't assume that the types
uint64_t and uint32_t exist.  Adapted from Gnulib patch
2012-05-27T06:40:00!eggert@cs.ucla.edu.  See:
https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=252b52457da7887667c036d18cc5169777615bb0
---
 ChangeLog       | 16 ++++++++++++++++
 posix/regcomp.c | 29 +++++++++++++++--------------
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3688c7f624..50da3df0b9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2017-11-20  Paul Eggert  <eggert@cs.ucla.edu>
+
+	regex: don't assume uint64_t or uint32_t
+	This avoids -Werror=overflow errors for 32-bit systems in
+	the 64-bit case.  Problem reported by Joseph Myers in:
+	https://sourceware.org/ml/libc-alpha/2017-11/msg00694.html
+	Also, when this code is used in Gnulib it ports to platforms
+	that lack uint64_t and uint32_t.  The C standard doesn't guarantee
+	them, and on some 32-bit compilers there is no uint64_t.
+	Problem reported by Gianluigi Tiesi in:
+	http://lists.gnu.org/archive/html/bug-gnulib/2012-03/msg00154.html
+	* posix/regcomp.c (init_word_char): Don't assume that the types
+	uint64_t and uint32_t exist.  Adapted from Gnulib patch
+	2012-05-27T06:40:00!eggert@cs.ucla.edu.  See:
+	https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=252b52457da7887667c036d18cc5169777615bb0
+
 2017-11-20  Siddhesh Poyarekar  <siddhesh@sourceware.org>
 
 	* sysdeps/aarch64/memset-reg.h: New file.
diff --git a/posix/regcomp.c b/posix/regcomp.c
index 871ae2ffab..520596b51b 100644
--- a/posix/regcomp.c
+++ b/posix/regcomp.c
@@ -925,26 +925,26 @@ init_word_char (re_dfa_t *dfa)
   int ch = 0;
   if (BE (dfa->map_notascii == 0, 1))
     {
-      if (sizeof (dfa->word_char[0]) == 8)
-	{
-          /* The extra temporaries here avoid "implicitly truncated"
-             warnings in the case when this is dead code, i.e. 32-bit.  */
-          const uint64_t wc0 = UINT64_C (0x03ff000000000000);
-          const uint64_t wc1 = UINT64_C (0x07fffffe87fffffe);
-	  dfa->word_char[0] = wc0;
-	  dfa->word_char[1] = wc1;
+      bitset_word_t bits0 = 0x00000000;
+      bitset_word_t bits1 = 0x03ff0000;
+      bitset_word_t bits2 = 0x87fffffe;
+      bitset_word_t bits3 = 0x07fffffe;
+      if (BITSET_WORD_BITS == 64)
+	{
+	  dfa->word_char[0] = bits1 << 31 << 1 | bits0;
+	  dfa->word_char[1] = bits3 << 31 << 1 | bits2;
 	  i = 2;
 	}
-      else if (sizeof (dfa->word_char[0]) == 4)
+      else if (BITSET_WORD_BITS == 32)
 	{
-	  dfa->word_char[0] = UINT32_C (0x00000000);
-	  dfa->word_char[1] = UINT32_C (0x03ff0000);
-	  dfa->word_char[2] = UINT32_C (0x87fffffe);
-	  dfa->word_char[3] = UINT32_C (0x07fffffe);
+	  dfa->word_char[0] = bits0;
+	  dfa->word_char[1] = bits1;
+	  dfa->word_char[2] = bits2;
+	  dfa->word_char[3] = bits3;
 	  i = 4;
 	}
       else
-	abort ();
+        goto general_case;
       ch = 128;
 
       if (BE (dfa->is_utf8, 1))
@@ -954,6 +954,7 @@ init_word_char (re_dfa_t *dfa)
 	}
     }
 
+ general_case:
   for (; i < BITSET_WORDS; ++i)
     for (int j = 0; j < BITSET_WORD_BITS; ++j, ++ch)
       if (isalnum (ch) || ch == '_')
-- 
2.14.3