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Make fingerprint handling compatible with LTO

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Tell the compiler that the fingerprint variable is modified unpredictably.

* lib/fingerprint.h (fingerprint): Remove const.
* lib/fingerprint.c (fingerprint): Likewise.
* src/pdumper.c (Fdump_emacs_portable): Cast fingerprint variable.
(pdumper_load): Likewise.
* lib-src/make-fingerprint.c (main): Likewise.
This commit is contained in:
Andreas Schwab 2019-07-09 21:12:14 +02:00
parent bff64115a0
commit fc41b0610e
4 changed files with 9 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

3
lib-src/make-fingerprint.c
View file

@ -144,7 +144,8 @@ main (int argc, char **argv)
for (char *finger = buf; for (char *finger = buf;
(finger = memmem (finger, buf + chunksz - finger, (finger = memmem (finger, buf + chunksz - finger,
fingerprint, sizeof fingerprint)); (unsigned char *) fingerprint,
sizeof fingerprint));
finger++) finger++)
{ {
if (! (fseeko (f, finger - buf, SEEK_SET) == 0 if (! (fseeko (f, finger - buf, SEEK_SET) == 0

2
lib/fingerprint.c
View file

@ -29,7 +29,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
by a fingerprint of the temporary Emacs executable that was built by a fingerprint of the temporary Emacs executable that was built
along the way. */ along the way. */
unsigned char const fingerprint[] = volatile unsigned char fingerprint[] =
{ {
0xDE, 0xDE,
0x86, 0x86,

2
lib/fingerprint.h
View file

@ -24,6 +24,6 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
Emacs. This way, we have a unique value that we can use to pair Emacs. This way, we have a unique value that we can use to pair
data files (like a portable dump image) with a specific build of data files (like a portable dump image) with a specific build of
Emacs. */ Emacs. */
extern unsigned char const fingerprint[32]; extern volatile unsigned char fingerprint[32];
#endif #endif

8
src/pdumper.c
View file

@ -4101,7 +4101,8 @@ types. */)
ctx->header.magic[0] = '!'; /* Note that dump is incomplete. */ ctx->header.magic[0] = '!'; /* Note that dump is incomplete. */
verify (sizeof (fingerprint) == sizeof (ctx->header.fingerprint)); verify (sizeof (fingerprint) == sizeof (ctx->header.fingerprint));
memcpy (ctx->header.fingerprint, fingerprint, sizeof (fingerprint)); memcpy (ctx->header.fingerprint, (unsigned char *) fingerprint,
sizeof (fingerprint));
const dump_off header_start = ctx->offset; const dump_off header_start = ctx->offset;
dump_fingerprint ("dumping fingerprint", ctx->header.fingerprint); dump_fingerprint ("dumping fingerprint", ctx->header.fingerprint);
@ -5359,9 +5360,10 @@ pdumper_load (const char *dump_filename)
err = PDUMPER_LOAD_VERSION_MISMATCH; err = PDUMPER_LOAD_VERSION_MISMATCH;
verify (sizeof (header->fingerprint) == sizeof (fingerprint)); verify (sizeof (header->fingerprint) == sizeof (fingerprint));
if (memcmp (header->fingerprint, fingerprint, sizeof (fingerprint)) != 0) if (memcmp (header->fingerprint, (unsigned char *) fingerprint,
sizeof (fingerprint)) != 0)
{ {
dump_fingerprint ("desired fingerprint", fingerprint); dump_fingerprint ("desired fingerprint", (unsigned char *) fingerprint);
dump_fingerprint ("found fingerprint", header->fingerprint); dump_fingerprint ("found fingerprint", header->fingerprint);
goto out; goto out;
} }