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| author | Jan Beulich <jbeulich@suse.com> | 2023-12-01 08:29:11 +0100 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2023-12-01 08:29:11 +0100 |
| commit | 0aa5d0c9e90a2bf26a99a0354ef500e971341de8 (patch) | |
| tree | 85d433719adc8ac8bfabd386e6c83db834103890 | |
| parent | ce69d08114bbd64ba0bec60ba1e51438abbd45d6 (diff) | |
| download | gdb-0aa5d0c9e90a2bf26a99a0354ef500e971341de8.zip gdb-0aa5d0c9e90a2bf26a99a0354ef500e971341de8.tar.gz gdb-0aa5d0c9e90a2bf26a99a0354ef500e971341de8.tar.bz2 | |
x86: adjust NOP generation after potential non-insn
Just like avoiding to do certain transformations potentially affected by
stand-alone prefixes or direct data emission, also avoid emitting
optimized NOPs right afterwards; insert a plain old NOP first in such
cases.
| -rw-r--r-- | gas/config/tc-i386.c | 8 | ||||
| -rw-r--r-- | gas/config/tc-i386.h | 6 |
2 files changed, 13 insertions, 1 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index e984923..4f3864f 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -1529,6 +1529,14 @@ i386_generate_nops (fragS *fragP, char *where, offsetT count, int limit) else if (fragP->fr_type != rs_machine_dependent) fragP->fr_var = count; + /* Emit a plain NOP first when the last thing we saw may not have been + a proper instruction (e.g. a stand-alone prefix or .byte). */ + if (!fragP->tc_frag_data.last_insn_normal) + { + *where++ = 0x90; + --count; + } + if ((count / max_single_nop_size) > max_number_of_nops) { /* Generate jump over NOPs. */ diff --git a/gas/config/tc-i386.h b/gas/config/tc-i386.h index c302214..6d6f0b9 100644 --- a/gas/config/tc-i386.h +++ b/gas/config/tc-i386.h @@ -321,6 +321,7 @@ struct i386_tc_frag_data unsigned int branch_type : 3; unsigned int cpunop : 1; unsigned int isanop : 1; + unsigned int last_insn_normal : 1; }; /* We need to emit the right NOP pattern in .align frags. This is @@ -347,7 +348,10 @@ struct i386_tc_frag_data (FRAGP)->tc_frag_data.cmp_size = 0; \ (FRAGP)->tc_frag_data.classified = 0; \ (FRAGP)->tc_frag_data.branch_type = 0; \ - (FRAGP)->tc_frag_data.mf_type = 0; \ + (FRAGP)->tc_frag_data.mf_type = 0; \ + (FRAGP)->tc_frag_data.last_insn_normal \ + = (seg_info(now_seg)->tc_segment_info_data.last_insn.kind \ + == last_insn_other); \ } \ while (0) |