diff options
Diffstat (limited to 'gas/config/tc-arm.c')
| -rw-r--r-- | gas/config/tc-arm.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c index bc8f775..2f6fea6 100644 --- a/gas/config/tc-arm.c +++ b/gas/config/tc-arm.c @@ -21623,6 +21623,8 @@ md_pcrel_from_section (fixS * fixP, segT seg) } } +static bfd_boolean flag_warn_syms = TRUE; + /* Under ELF we need to default _GLOBAL_OFFSET_TABLE. Otherwise we have no need to default values of symbols. */ @@ -21646,6 +21648,52 @@ md_undefined_symbol (char * name ATTRIBUTE_UNUSED) } #endif + /* PR 18347 - Warn if the user attempts to create a symbol with the same + name as an ARM instruction. Whilst strictly speaking it is allowed, it + does mean that the resulting code might be very confusing to the reader. + Also this warning can be triggered if the user omits an operand before + an immediate address, eg: + + LDR =foo + + GAS treats this as an assignment of the value of the symbol foo to a + symbol LDR, and so (without this code) it will not issue any kind of + warning or error message. + + Note - ARM instructions are case-insensitive but the strings in the hash + table are all stored in lower case, so we must first ensure that name is + lower case too. + + Some names are problematical. Several gas tests for example use: + + b: + + as a label, but of course this matches the branch instruction. For now + we punt and only check names longer than 1. + + FIXME: Should this be made into generic code for all targets ? */ + if (flag_warn_syms && arm_ops_hsh && strlen (name) > 1) + { + char * nbuf = strdup (name); + char * p; + + for (p = nbuf; *p; p++) + *p = TOLOWER (*p); + if (hash_find (arm_ops_hsh, nbuf) != NULL) + { + static struct hash_control * already_warned = NULL; + + if (already_warned == NULL) + already_warned = hash_new (); + /* Only warn about the symbol once. To keep the code + simple we let hash_insert do the lookup for us. */ + if (hash_insert (already_warned, name, NULL) == NULL) + as_warn (_("[-mwarn-syms]: Symbol '%s' matches an ARM instruction - is this intentional ?"), name); + } + else + free (nbuf); + } + return NULL; } @@ -24116,6 +24164,7 @@ md_begin (void) -mthumb-interwork Code supports ARM/Thumb interworking -m[no-]warn-deprecated Warn about deprecated features + -m[no-]warn-syms Warn when symbols match instructions For now we will also provide support for: @@ -24184,6 +24233,7 @@ struct option md_longopts[] = {NULL, no_argument, NULL, 0} }; + size_t md_longopts_size = sizeof (md_longopts); struct arm_option_table @@ -24218,6 +24268,8 @@ struct arm_option_table arm_opts[] = {"mwarn-deprecated", NULL, &warn_on_deprecated, 1, NULL}, {"mno-warn-deprecated", N_("do not warn on use of deprecated feature"), &warn_on_deprecated, 0, NULL}, + {"mwarn-syms", N_("warn about symbols that match instruction names [default]"), (int *) (& flag_warn_syms), TRUE, NULL}, + {"mno-warn-syms", N_("disable warnings about symobls that match instructions"), (int *) (& flag_warn_syms), FALSE, NULL}, {NULL, NULL, NULL, 0, NULL} }; |