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Bug 983817 - Pad heap allocations passed to flag_qsort() on x86 Linux to work around gcc bug affecting Ubuntu packages. r=froydnj

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My biggest concern for review of this patch is whether the #ifdef will
correctly catch what Ubuntu is using to compile Firefox.  Does anybody
know how to confirm that Ubuntu is compiling with gcc, and that these
#ifdefs are correct?

--HG--
extra : transplant_source : %CB%A0%0A%F6Y%93%0Cp%EBY%40%E20%95%0E%3E%AD%0F%9E%12
This commit is contained in:
L. David Baron 2015-02-10 10:10:49 +11:00
parent abb4bb800d
commit ace9185d6f
1 changed files with 24 additions and 6 deletions
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30
extensions/spellcheck/hunspell/src/hashmgr.cxx
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@ -11,6 +11,20 @@
#include "csutil.hxx"
#include "atypes.hxx"
// The gcc used to build 32-bit builds of Firefox on Ubuntu
// miscompiles flag_qsort, using a 32-bit read instead of a 16-bit
// read while quicksorting an array of 16-bit units. This causes
// one of the top Firefox crashes.
// Given that I haven't been able to produce a reduced testcase to give
// to gcc developers, just work around the bug by allocating an extra 2
// bytes on the heap arrays passed to flag_qsort().
// See https://bugzilla.mozilla.org/show_bug.cgi?id=983817 .
#if defined(__linux__) && defined(__i386__) && defined(__GNUC__)
#define EXTRA_QSORT_ALLOC_SIZE 1
#else
#define EXTRA_QSORT_ALLOC_SIZE 0
#endif
// build a hash table from a munched word list
HashMgr::HashMgr(const char * tpath, const char * apath, const char * key)
@ -265,8 +279,8 @@ int HashMgr::remove(const char * word)
struct hentry * dp = lookup(word);
while (dp) {
if (dp->alen == 0 || !TESTAFF(dp->astr, forbiddenword, dp->alen)) {
unsigned short * flags =
(unsigned short *) malloc(sizeof(short) * (dp->alen + 1));
unsigned short * flags = (unsigned short *)
malloc(sizeof(short) * (dp->alen + 1 + EXTRA_QSORT_ALLOC_SIZE));
if (!flags) return 1;
for (int i = 0; i < dp->alen; i++) flags[i] = dp->astr[i];
flags[dp->alen] = forbiddenword;
@ -508,7 +522,8 @@ int HashMgr::decode_flags(unsigned short ** result, char * flags, FileMgr * af)
len = strlen(flags);
if (len%2 == 1) HUNSPELL_WARNING(stderr, "error: line %d: bad flagvector\n", af->getlinenum());
len /= 2;
*result = (unsigned short *) malloc(len * sizeof(short));
*result = (unsigned short *)
malloc((len + EXTRA_QSORT_ALLOC_SIZE) * sizeof(short));
if (!*result) return -1;
for (int i = 0; i < len; i++) {
(*result)[i] = (((unsigned short) flags[i * 2]) << 8) + (unsigned short) flags[i * 2 + 1];
@ -524,7 +539,8 @@ int HashMgr::decode_flags(unsigned short ** result, char * flags, FileMgr * af)
for (p = flags; *p; p++) {
if (*p == ',') len++;
}
*result = (unsigned short *) malloc(len * sizeof(short));
*result = (unsigned short *)
malloc((len + EXTRA_QSORT_ALLOC_SIZE) * sizeof(short));
if (!*result) return -1;
dest = *result;
for (p = flags; *p; p++) {
@ -548,7 +564,8 @@ int HashMgr::decode_flags(unsigned short ** result, char * flags, FileMgr * af)
case FLAG_UNI: { // UTF-8 characters
w_char w[BUFSIZE/2];
len = u8_u16(w, BUFSIZE/2, flags);
*result = (unsigned short *) malloc(len * sizeof(short));
*result =
(unsigned short *) malloc((len + EXTRA_QSORT_ALLOC_SIZE) * sizeof(short));
if (!*result) return -1;
memcpy(*result, w, len * sizeof(short));
break;
@ -556,7 +573,8 @@ int HashMgr::decode_flags(unsigned short ** result, char * flags, FileMgr * af)
default: { // Ispell's one-character flags (erfg -> e r f g)
unsigned short * dest;
len = strlen(flags);
*result = (unsigned short *) malloc(len * sizeof(short));
*result = (unsigned short *)
malloc((len + EXTRA_QSORT_ALLOC_SIZE) * sizeof(short));
if (!*result) return -1;
dest = *result;
for (unsigned char * p = (unsigned char *) flags; *p; p++) {