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authorAlan Modra <amodra@gmail.com>2018-01-31 13:34:18 +1030
committerAlan Modra <amodra@gmail.com>2018-01-31 16:58:26 +1030
commitab1fadc6b2f057b817e1fc093650b63d9f6dd6c5 (patch)
treee55f2c97682850714204488b0b4bcd859f416ac6 /gas/app.c
parent29236ca20ad953ead58ab791ec376ee7921624b8 (diff)
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PR22714, Assembler preprocessor loses track of \@
The PR22714 testcase is such that the input buffer processed by do_scrub_chars ends on this line 1: bug "Returning to usermode but unexpected PSR bits set?", \@ right at the backslash. (The line is part of a macro definition.) The next input buffer then starts with '@' which starts a comment on ARM, and the check for \@ fails due to to == tostart. Now it would be possible to simply access to[-1] in this particular case, but that's ugly, and to be absolutely safe from people deliberately trying to crash gas we'd need the read.c:read_a_source_file buffer passed to do_scrub_chars to have a single byte pad at the start. PR 22714 * app.c (last_char): New static var. (struct app_save): Add last_char field. (app_push, app_pop): Handle it. (do_scrub_chars): Use last_char in test for "\@". Set last_char.
Diffstat (limited to 'gas/app.c')
-rw-r--r--gas/app.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/gas/app.c b/gas/app.c
index da39421..9cafff0 100644
--- a/gas/app.c
+++ b/gas/app.c
@@ -55,6 +55,9 @@ static const char mri_pseudo[] = ".mri 0";
static const char symver_pseudo[] = ".symver";
static const char * symver_state;
#endif
+#ifdef TC_ARM
+static char last_char;
+#endif
static char lex[256];
static const char symbol_chars[] =
@@ -242,6 +245,9 @@ struct app_save
#if defined TC_ARM && defined OBJ_ELF
const char * symver_state;
#endif
+#ifdef TC_ARM
+ char last_char;
+#endif
};
char *
@@ -271,6 +277,9 @@ app_push (void)
#if defined TC_ARM && defined OBJ_ELF
saved->symver_state = symver_state;
#endif
+#ifdef TC_ARM
+ saved->last_char = last_char;
+#endif
/* do_scrub_begin() is not useful, just wastes time. */
@@ -310,6 +319,9 @@ app_pop (char *arg)
#if defined TC_ARM && defined OBJ_ELF
symver_state = saved->symver_state;
#endif
+#ifdef TC_ARM
+ last_char = saved->last_char;
+#endif
free (arg);
}
@@ -1285,7 +1297,7 @@ do_scrub_chars (size_t (*get) (char *, size_t), char *tostart, size_t tolen)
#ifdef TC_ARM
/* For the ARM, care is needed not to damage occurrences of \@
by stripping the @ onwards. Yuck. */
- if (to > tostart && *(to - 1) == '\\')
+ if ((to > tostart ? to[-1] : last_char) == '\\')
/* Do not treat the @ as a start-of-comment. */
goto de_fault;
#endif
@@ -1465,6 +1477,10 @@ do_scrub_chars (size_t (*get) (char *, size_t), char *tostart, size_t tolen)
fromeof:
/* We have reached the end of the input. */
+#ifdef TC_ARM
+ if (to > tostart)
+ last_char = to[-1];
+#endif
return to - tostart;
tofull:
@@ -1478,5 +1494,9 @@ do_scrub_chars (size_t (*get) (char *, size_t), char *tostart, size_t tolen)
else
saved_input = NULL;
+#ifdef TC_ARM
+ if (to > tostart)
+ last_char = to[-1];
+#endif
return to - tostart;
}