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tcg: Introduce INDEX_op_qemu_st8_i32

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Enable this on i386 to restrict the set of input registers
for an 8-bit store, as required by the architecture.  This
removes the last use of scratch registers for user-only mode.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2020-12-09 13:58:39 -06:00
parent d2ef1b83a7
commit 07ce0b0530
15 changed files with 49 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

29
tcg/i386/tcg-target.c.inc
View file

@ -245,11 +245,21 @@ static const char *target_parse_constraint(TCGArgConstraint *ct,
ct->regs |= ALL_VECTOR_REGS;
break;
/* qemu_ld/st address constraint */
case 'L':
/* qemu_ld/st data+address constraint */
ct->regs = TCG_TARGET_REG_BITS == 64 ? 0xffff : 0xff;
#ifdef CONFIG_SOFTMMU
tcg_regset_reset_reg(ct->regs, TCG_REG_L0);
tcg_regset_reset_reg(ct->regs, TCG_REG_L1);
#endif
break;
case 's':
/* qemu_st8_i32 data constraint */
ct->regs = 0xf;
#ifdef CONFIG_SOFTMMU
tcg_regset_reset_reg(ct->regs, TCG_REG_L0);
tcg_regset_reset_reg(ct->regs, TCG_REG_L1);
#endif
break;
case 'e':
@ -2120,7 +2130,6 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi,
TCGReg base, int index, intptr_t ofs,
int seg, MemOp memop)
{
const TCGReg scratch = TCG_REG_L0;
bool use_movbe = false;
int movop = OPC_MOVL_EvGv;
@ -2136,15 +2145,8 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi,
switch (memop & MO_SIZE) {
case MO_8:
/*
* In 32-bit mode, 8-bit stores can only happen from [abcd]x.
* TODO: Adjust constraints such that this is is forced,
* then we won't need a scratch at all for user-only.
*/
if (TCG_TARGET_REG_BITS == 32 && datalo >= 4) {
tcg_out_mov(s, TCG_TYPE_I32, scratch, datalo);
datalo = scratch;
}
/* This is handled with constraints on INDEX_op_qemu_st8_i32. */
tcg_debug_assert(TCG_TARGET_REG_BITS == 64 || datalo < 4);
tcg_out_modrm_sib_offset(s, OPC_MOVB_EvGv + P_REXB_R + seg,
datalo, base, index, 0, ofs);
break;
@ -2491,6 +2493,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
tcg_out_qemu_ld(s, args, 1);
break;
case INDEX_op_qemu_st_i32:
case INDEX_op_qemu_st8_i32:
tcg_out_qemu_st(s, args, 0);
break;
case INDEX_op_qemu_st_i64:
@ -2949,9 +2952,11 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op)
static const TCGTargetOpDef r_0_ci = { .args_ct_str = { "r", "0", "ci" } };
static const TCGTargetOpDef r_L = { .args_ct_str = { "r", "L" } };
static const TCGTargetOpDef L_L = { .args_ct_str = { "L", "L" } };
static const TCGTargetOpDef s_L = { .args_ct_str = { "s", "L" } };
static const TCGTargetOpDef r_L_L = { .args_ct_str = { "r", "L", "L" } };
static const TCGTargetOpDef r_r_L = { .args_ct_str = { "r", "r", "L" } };
static const TCGTargetOpDef L_L_L = { .args_ct_str = { "L", "L", "L" } };
static const TCGTargetOpDef s_L_L = { .args_ct_str = { "s", "L", "L" } };
static const TCGTargetOpDef r_r_L_L
= { .args_ct_str = { "r", "r", "L", "L" } };
static const TCGTargetOpDef L_L_L_L
@ -3145,6 +3150,8 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op)
return TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? &r_L : &r_L_L;
case INDEX_op_qemu_st_i32:
return TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? &L_L : &L_L_L;
case INDEX_op_qemu_st8_i32:
return TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? &s_L : &s_L_L;
case INDEX_op_qemu_ld_i64:
return (TCG_TARGET_REG_BITS == 64 ? &r_L
: TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? &r_r_L

3
tcg/i386/tcg-target.h
View file

@ -172,6 +172,9 @@ extern bool have_movbe;
#define TCG_TARGET_HAS_muls2_i64 1
#define TCG_TARGET_HAS_muluh_i64 0
#define TCG_TARGET_HAS_mulsh_i64 0
#define TCG_TARGET_HAS_qemu_st8_i32 0
#else
#define TCG_TARGET_HAS_qemu_st8_i32 1
#endif
/* We do not support older SSE systems, only beginning with AVX1. */