From: Jan Beulich <jbeulich@suse.com>
To: Binutils <binutils@sourceware.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Subject: [PATCH 7/8] x86: embed register and alike names in disassembler
Date: Fri, 13 Jan 2023 12:11:01 +0100 [thread overview]
Message-ID: <8a6f1fce-435a-b8fa-44a3-c7ae2c621968@suse.com> (raw)
In-Reply-To: <beeaf9c6-7d1e-bcc6-624a-918c4a6c293e@suse.com>
Register names are (including their nul terminators) on average almost 4
bytes long. Otoh no register name is longer than 8 bytes. Hence even for
32-bit builds using a pointer is only slightly more space efficient than
embedding the strings. A level of indirection can be also avoided by
embedding the names as an array of 8 characters directly in the arrays,
and the number of base relocations in libopcodes.so (or PIE builds of
statically linked executables) goes down as well.
To amortize for the otherwise reduced folding of string literals by the
linker, use att_names_seg[] in place of string literals in append_seg()
and OP_ESreg().
--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -2462,48 +2462,48 @@ struct op
need to update onebyte_has_modrm or twobyte_has_modrm. */
#define MODRM_CHECK if (!ins->need_modrm) abort ()
-static const char *const intel_index16[] = {
+static const char intel_index16[][6] = {
"bx+si", "bx+di", "bp+si", "bp+di", "si", "di", "bp", "bx"
};
-static const char *const att_names64[] = {
+static const char att_names64[][8] = {
"%rax", "%rcx", "%rdx", "%rbx", "%rsp", "%rbp", "%rsi", "%rdi",
"%r8", "%r9", "%r10", "%r11", "%r12", "%r13", "%r14", "%r15"
};
-static const char *const att_names32[] = {
+static const char att_names32[][8] = {
"%eax", "%ecx", "%edx", "%ebx", "%esp", "%ebp", "%esi", "%edi",
"%r8d", "%r9d", "%r10d", "%r11d", "%r12d", "%r13d", "%r14d", "%r15d"
};
-static const char *const att_names16[] = {
+static const char att_names16[][8] = {
"%ax", "%cx", "%dx", "%bx", "%sp", "%bp", "%si", "%di",
"%r8w", "%r9w", "%r10w", "%r11w", "%r12w", "%r13w", "%r14w", "%r15w"
};
-static const char *const att_names8[] = {
+static const char att_names8[][8] = {
"%al", "%cl", "%dl", "%bl", "%ah", "%ch", "%dh", "%bh",
};
-static const char *const att_names8rex[] = {
+static const char att_names8rex[][8] = {
"%al", "%cl", "%dl", "%bl", "%spl", "%bpl", "%sil", "%dil",
"%r8b", "%r9b", "%r10b", "%r11b", "%r12b", "%r13b", "%r14b", "%r15b"
};
-static const char *const att_names_seg[] = {
+static const char att_names_seg[][4] = {
"%es", "%cs", "%ss", "%ds", "%fs", "%gs", "%?", "%?",
};
static const char att_index64[] = "%riz";
static const char att_index32[] = "%eiz";
-static const char *const att_index16[] = {
+static const char att_index16[][8] = {
"%bx,%si", "%bx,%di", "%bp,%si", "%bp,%di", "%si", "%di", "%bp", "%bx"
};
-static const char *const att_names_mm[] = {
+static const char att_names_mm[][8] = {
"%mm0", "%mm1", "%mm2", "%mm3",
"%mm4", "%mm5", "%mm6", "%mm7"
};
-static const char *const att_names_bnd[] = {
+static const char att_names_bnd[][8] = {
"%bnd0", "%bnd1", "%bnd2", "%bnd3"
};
-static const char *const att_names_xmm[] = {
+static const char att_names_xmm[][8] = {
"%xmm0", "%xmm1", "%xmm2", "%xmm3",
"%xmm4", "%xmm5", "%xmm6", "%xmm7",
"%xmm8", "%xmm9", "%xmm10", "%xmm11",
@@ -2514,7 +2514,7 @@ static const char *const att_names_xmm[]
"%xmm28", "%xmm29", "%xmm30", "%xmm31"
};
-static const char *const att_names_ymm[] = {
+static const char att_names_ymm[][8] = {
"%ymm0", "%ymm1", "%ymm2", "%ymm3",
"%ymm4", "%ymm5", "%ymm6", "%ymm7",
"%ymm8", "%ymm9", "%ymm10", "%ymm11",
@@ -2525,7 +2525,7 @@ static const char *const att_names_ymm[]
"%ymm28", "%ymm29", "%ymm30", "%ymm31"
};
-static const char *const att_names_zmm[] = {
+static const char att_names_zmm[][8] = {
"%zmm0", "%zmm1", "%zmm2", "%zmm3",
"%zmm4", "%zmm5", "%zmm6", "%zmm7",
"%zmm8", "%zmm9", "%zmm10", "%zmm11",
@@ -2536,12 +2536,12 @@ static const char *const att_names_zmm[]
"%zmm28", "%zmm29", "%zmm30", "%zmm31"
};
-static const char *const att_names_tmm[] = {
+static const char att_names_tmm[][8] = {
"%tmm0", "%tmm1", "%tmm2", "%tmm3",
"%tmm4", "%tmm5", "%tmm6", "%tmm7"
};
-static const char *const att_names_mask[] = {
+static const char att_names_mask[][8] = {
"%k0", "%k1", "%k2", "%k3", "%k4", "%k5", "%k6", "%k7"
};
@@ -11291,22 +11291,22 @@ append_seg (instr_info *ins)
switch (ins->active_seg_prefix)
{
case PREFIX_CS:
- oappend_register (ins, "%cs");
+ oappend_register (ins, att_names_seg[1]);
break;
case PREFIX_DS:
- oappend_register (ins, "%ds");
+ oappend_register (ins, att_names_seg[3]);
break;
case PREFIX_SS:
- oappend_register (ins, "%ss");
+ oappend_register (ins, att_names_seg[2]);
break;
case PREFIX_ES:
- oappend_register (ins, "%es");
+ oappend_register (ins, att_names_seg[0]);
break;
case PREFIX_FS:
- oappend_register (ins, "%fs");
+ oappend_register (ins, att_names_seg[4]);
break;
case PREFIX_GS:
- oappend_register (ins, "%gs");
+ oappend_register (ins, att_names_seg[5]);
break;
default:
break;
@@ -11649,7 +11649,7 @@ static void
print_register (instr_info *ins, unsigned int reg, unsigned int rexmask,
int bytemode, int sizeflag)
{
- const char *const *names;
+ const char (*names)[8];
USED_REX (rexmask);
if (ins->rex & rexmask)
@@ -11888,7 +11888,7 @@ OP_E_memory (instr_info *ins, int bytemo
|| bytemode == bnd_mode
|| bytemode == bnd_swap_mode);
bool check_gather = false;
- const char *const *indexes = NULL;
+ const char (*indexes)[8] = NULL;
havebase = 1;
base = ins->modrm.rm;
@@ -12177,8 +12177,8 @@ OP_E_memory (instr_info *ins, int bytemo
if (ins->modrm.mod != 0 || ins->modrm.rm != 6)
{
oappend_char (ins, ins->open_char);
- oappend (ins, (ins->intel_syntax ? intel_index16
- : att_index16)[ins->modrm.rm]);
+ oappend (ins, ins->intel_syntax ? intel_index16[ins->modrm.rm]
+ : att_index16[ins->modrm.rm]);
if (ins->intel_syntax
&& (disp || ins->modrm.mod != 0 || ins->modrm.rm == 6))
{
@@ -12801,7 +12801,7 @@ OP_ESreg (instr_info *ins, int code, int
intel_operand_size (ins, b_mode, sizeflag);
}
}
- oappend_register (ins, "%es");
+ oappend_register (ins, att_names_seg[0]);
oappend_char (ins, ':');
ptr_reg (ins, code, sizeflag);
}
@@ -12898,7 +12898,7 @@ OP_MMX (instr_info *ins, int bytemode AT
int sizeflag ATTRIBUTE_UNUSED)
{
int reg = ins->modrm.reg;
- const char *const *names;
+ const char (*names)[8];
ins->used_prefixes |= (ins->prefixes & PREFIX_DATA);
if (ins->prefixes & PREFIX_DATA)
@@ -12916,7 +12916,7 @@ OP_MMX (instr_info *ins, int bytemode AT
static void
print_vector_reg (instr_info *ins, unsigned int reg, int bytemode)
{
- const char *const *names;
+ const char (*names)[8];
if (bytemode == xmmq_mode
|| bytemode == evex_half_bcst_xmmqh_mode
@@ -13014,7 +13014,7 @@ static void
OP_EM (instr_info *ins, int bytemode, int sizeflag)
{
int reg;
- const char *const *names;
+ const char (*names)[8];
if (ins->modrm.mod != 3)
{
@@ -13370,8 +13370,8 @@ OP_Monitor (instr_info *ins, int bytemod
/* monitor %{e,r,}ax,%ecx,%edx" */
if (!ins->intel_syntax)
{
- const char *const *names = (ins->address_mode == mode_64bit
- ? att_names64 : att_names32);
+ const char (*names)[8] = (ins->address_mode == mode_64bit
+ ? att_names64 : att_names32);
if (ins->prefixes & PREFIX_ADDR)
{
@@ -13547,7 +13547,7 @@ CMPXCHG8B_Fixup (instr_info *ins, int by
static void
XMM_Fixup (instr_info *ins, int reg, int sizeflag ATTRIBUTE_UNUSED)
{
- const char *const *names = att_names_xmm;
+ const char (*names)[8] = att_names_xmm;
if (ins->need_vex)
{
@@ -13588,7 +13588,7 @@ static void
OP_VEX (instr_info *ins, int bytemode, int sizeflag ATTRIBUTE_UNUSED)
{
int reg, modrm_reg, sib_index = -1;
- const char *const *names;
+ const char (*names)[8];
if (!ins->need_vex)
abort ();
@@ -13763,7 +13763,7 @@ static void
OP_REG_VexI4 (instr_info *ins, int bytemode, int sizeflag ATTRIBUTE_UNUSED)
{
int reg;
- const char *const *names = att_names_xmm;
+ const char (*names)[8] = att_names_xmm;
FETCH_DATA (ins->info, ins->codep + 1);
reg = *ins->codep++;
next prev parent reply other threads:[~2023-01-13 11:11 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 ` [PATCH 3/8] x86: re-use insn mnemonic strings as much as possible Jan Beulich
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 ` Jan Beulich [this message]
2023-01-13 11:11 ` [PATCH 8/8] x86: split i386-gen's opcode hash entry struct Jan Beulich
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