From: Jan Beulich <jbeulich@suse.com>
To: Binutils <binutils@sourceware.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Subject: [PATCH 3/8] x86: re-use insn mnemonic strings as much as possible
Date: Fri, 13 Jan 2023 12:07:24 +0100 [thread overview]
Message-ID: <d87c0ed5-4678-d8ea-9744-7447ff82a843@suse.com> (raw)
In-Reply-To: <beeaf9c6-7d1e-bcc6-624a-918c4a6c293e@suse.com>
Compact the mnemonic string table such that the tails of longer
mnemonics are re-used for shorter ones, going beyond what compilers
would typically do, but matching what ELF linkers may do when processing
SHF_MERGE|SHF_STRINGS sections. This reduces table size by about 12.5%.
--- a/opcodes/i386-gen.c
+++ b/opcodes/i386-gen.c
@@ -1576,12 +1576,29 @@ expand_templates (char *name, const char
return idx;
}
+static int mnemonic_cmp(const void *p1, const void *p2)
+{
+ const struct opcode_hash_entry *const *e1 = p1, *const *e2 = p2;
+ const char *s1 = (*e1)->name, *s2 = (*e2)->name;
+ unsigned int i;
+ size_t l1 = strlen (s1), l2 = strlen (s2);
+
+ for (i = 1; i <= l1 && i <= l2; ++i)
+ {
+ if (s1[l1 - i] != s2[l2 - i])
+ return (unsigned char)s1[l1 - i] - (unsigned char)s2[l2 - i];
+ }
+
+ return (int)(l1 - l2);
+}
+
static void
process_i386_opcodes (FILE *table)
{
FILE *fp;
char buf[2048];
unsigned int i, j, nr, offs;
+ size_t l;
char *str, *p, *last, *name;
htab_t opcode_hash_table;
struct opcode_hash_entry **opcode_array = NULL;
@@ -1720,6 +1737,8 @@ process_i386_opcodes (FILE *table)
fprintf (table, "};\n");
/* Emit mnemonics and associated #define-s. */
+ qsort (opcode_array, i, sizeof (*opcode_array), mnemonic_cmp);
+
fp = fopen ("i386-mnem.h", "w");
if (fp == NULL)
fail (_("can't create i386-mnem.h, errno = %s\n"),
@@ -1731,14 +1750,28 @@ process_i386_opcodes (FILE *table)
fprintf (table, "const char i386_mnemonics[] =\n");
fprintf (fp, "\nextern const char i386_mnemonics[];\n\n");
- for (offs = j = 0; j < i; j++)
+ for (l = strlen (opcode_array[offs = j = 0]->name); j < i; j++)
{
+ const char *next = NULL;
+ size_t l1 = j + 1 < i ? strlen(next = opcode_array[j + 1]->name) : 0;
+
name = opcode_array[j]->name;
- fprintf (table, " \"\\0\"\"%s\"\n", name);
str = mkident (name);
- fprintf (fp, "#define MN_%s %#x\n", str, offs + 1);
+ if (l < l1 && !strcmp(name, next + l1 - l))
+ {
+ fprintf (fp, "#define MN_%s ", str);
+ free (str);
+ str = mkident (next);
+ fprintf (fp, "(MN_%s + %u)\n", str, l1 - l);
+ }
+ else
+ {
+ fprintf (table, " \"\\0\"\"%s\"\n", name);
+ fprintf (fp, "#define MN_%s %#x\n", str, offs + 1);
+ offs += strlen (name) + 1;
+ }
free (str);
- offs += strlen (name) + 1;
+ l = l1;
}
fprintf (table, ";\n");
next prev parent reply other threads:[~2023-01-13 11:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 11:04 [PATCH 0/8] x86: mnemonic and register string literals Jan Beulich
2023-01-13 11:05 ` [PATCH 1/8] x86: abstract out obtaining of a template's mnemonic Jan Beulich
2023-01-13 11:06 ` [PATCH 1/8] x86: move insn mnemonics to a separate table Jan Beulich
2023-01-13 11:12 ` Jan Beulich
2023-01-13 11:07 ` Jan Beulich [this message]
2023-01-13 11:07 ` [PATCH 4/8] x86: absorb allocation in i386-gen Jan Beulich
2023-01-13 11:08 ` [PATCH 5/8] x86: avoid strcmp() in a few places Jan Beulich
2023-01-13 11:10 ` [PATCH 6/8] x86: embed register names in reg_entry Jan Beulich
2023-01-13 11:11 ` [PATCH 7/8] x86: embed register and alike names in disassembler Jan Beulich
2023-01-13 11:11 ` [PATCH 8/8] x86: split i386-gen's opcode hash entry struct Jan Beulich
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