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tcg: Introduce tcg_out_movext2
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This is common code in most qemu_{ld,st} slow paths, moving two
registers when there may be overlap between sources and destinations.
At present, this is only used by 32-bit hosts for 64-bit data,
but will shortly be used for more than that.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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rth7680 committed May 2, 2023
1 parent 7f98ec2 commit bdc7fba
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Showing 3 changed files with 90 additions and 42 deletions.
44 changes: 18 additions & 26 deletions tcg/arm/tcg-target.c.inc
Original file line number Diff line number Diff line change
Expand Up @@ -1545,7 +1545,7 @@ static void add_qemu_ldst_label(TCGContext *s, bool is_ld, MemOpIdx oi,

static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
{
TCGReg argreg, datalo, datahi;
TCGReg argreg;
MemOpIdx oi = lb->oi;
MemOp opc = get_memop(oi);

Expand All @@ -1565,22 +1565,16 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
/* Use the canonical unsigned helpers and minimize icache usage. */
tcg_out_call_int(s, qemu_ld_helpers[opc & MO_SIZE]);

datalo = lb->datalo_reg;
datahi = lb->datahi_reg;
if ((opc & MO_SIZE) == MO_64) {
if (datalo != TCG_REG_R1) {
tcg_out_mov_reg(s, COND_AL, datalo, TCG_REG_R0);
tcg_out_mov_reg(s, COND_AL, datahi, TCG_REG_R1);
} else if (datahi != TCG_REG_R0) {
tcg_out_mov_reg(s, COND_AL, datahi, TCG_REG_R1);
tcg_out_mov_reg(s, COND_AL, datalo, TCG_REG_R0);
} else {
tcg_out_mov_reg(s, COND_AL, TCG_REG_TMP, TCG_REG_R0);
tcg_out_mov_reg(s, COND_AL, datahi, TCG_REG_R1);
tcg_out_mov_reg(s, COND_AL, datalo, TCG_REG_TMP);
}
TCGMovExtend ext[2] = {
{ .dst = lb->datalo_reg, .dst_type = TCG_TYPE_I32,
.src = TCG_REG_R0, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
{ .dst = lb->datahi_reg, .dst_type = TCG_TYPE_I32,
.src = TCG_REG_R1, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
};
tcg_out_movext2(s, &ext[0], &ext[1], TCG_REG_TMP);
} else {
tcg_out_movext(s, TCG_TYPE_I32, datalo,
tcg_out_movext(s, TCG_TYPE_I32, lb->datalo_reg,
TCG_TYPE_I32, opc & MO_SSIZE, TCG_REG_R0);
}

Expand Down Expand Up @@ -1663,17 +1657,15 @@ static bool tcg_out_fail_alignment(TCGContext *s, TCGLabelQemuLdst *l)

if (TARGET_LONG_BITS == 64) {
/* 64-bit target address is aligned into R2:R3. */
if (l->addrhi_reg != TCG_REG_R2) {
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R2, l->addrlo_reg);
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R3, l->addrhi_reg);
} else if (l->addrlo_reg != TCG_REG_R3) {
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R3, l->addrhi_reg);
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R2, l->addrlo_reg);
} else {
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R1, TCG_REG_R2);
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R2, TCG_REG_R3);
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R3, TCG_REG_R1);
}
TCGMovExtend ext[2] = {
{ .dst = TCG_REG_R2, .dst_type = TCG_TYPE_I32,
.src = l->addrlo_reg,
.src_type = TCG_TYPE_I32, .src_ext = MO_UL },
{ .dst = TCG_REG_R3, .dst_type = TCG_TYPE_I32,
.src = l->addrhi_reg,
.src_type = TCG_TYPE_I32, .src_ext = MO_UL },
};
tcg_out_movext2(s, &ext[0], &ext[1], TCG_REG_TMP);
} else {
tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R1, l->addrlo_reg);
}
Expand Down
19 changes: 8 additions & 11 deletions tcg/i386/tcg-target.c.inc
Original file line number Diff line number Diff line change
Expand Up @@ -1914,7 +1914,6 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
{
MemOpIdx oi = l->oi;
MemOp opc = get_memop(oi);
TCGReg data_reg;
tcg_insn_unit **label_ptr = &l->label_ptr[0];

/* resolve label address */
Expand Down Expand Up @@ -1951,18 +1950,16 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)

tcg_out_branch(s, 1, qemu_ld_helpers[opc & (MO_BSWAP | MO_SIZE)]);

data_reg = l->datalo_reg;
if (TCG_TARGET_REG_BITS == 32 && (opc & MO_SIZE) == MO_64) {
if (data_reg == TCG_REG_EDX) {
/* xchg %edx, %eax */
tcg_out_opc(s, OPC_XCHG_ax_r32 + TCG_REG_EDX, 0, 0, 0);
tcg_out_mov(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_EAX);
} else {
tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
tcg_out_mov(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_EDX);
}
TCGMovExtend ext[2] = {
{ .dst = l->datalo_reg, .dst_type = TCG_TYPE_I32,
.src = TCG_REG_EAX, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
{ .dst = l->datahi_reg, .dst_type = TCG_TYPE_I32,
.src = TCG_REG_EDX, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
};
tcg_out_movext2(s, &ext[0], &ext[1], -1);
} else {
tcg_out_movext(s, l->type, data_reg,
tcg_out_movext(s, l->type, l->datalo_reg,
TCG_TYPE_REG, opc & MO_SSIZE, TCG_REG_EAX);
}

Expand Down
69 changes: 64 additions & 5 deletions tcg/tcg.c
Original file line number Diff line number Diff line change
Expand Up @@ -115,8 +115,7 @@ static void tcg_out_exts_i32_i64(TCGContext *s, TCGReg ret, TCGReg arg);
static void tcg_out_extu_i32_i64(TCGContext *s, TCGReg ret, TCGReg arg);
static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg ret, TCGReg arg);
static void tcg_out_addi_ptr(TCGContext *s, TCGReg, TCGReg, tcg_target_long);
static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
__attribute__((unused));
static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2);
static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg);
static void tcg_out_goto_tb(TCGContext *s, int which);
static void tcg_out_op(TCGContext *s, TCGOpcode opc,
Expand Down Expand Up @@ -354,6 +353,14 @@ void tcg_raise_tb_overflow(TCGContext *s)
siglongjmp(s->jmp_trans, -2);
}

typedef struct TCGMovExtend {
TCGReg dst;
TCGReg src;
TCGType dst_type;
TCGType src_type;
MemOp src_ext;
} TCGMovExtend;

/**
* tcg_out_movext -- move and extend
* @s: tcg context
Expand All @@ -365,9 +372,8 @@ void tcg_raise_tb_overflow(TCGContext *s)
*
* Move or extend @src into @dst, depending on @src_ext and the types.
*/
static void __attribute__((unused))
tcg_out_movext(TCGContext *s, TCGType dst_type, TCGReg dst,
TCGType src_type, MemOp src_ext, TCGReg src)
static void tcg_out_movext(TCGContext *s, TCGType dst_type, TCGReg dst,
TCGType src_type, MemOp src_ext, TCGReg src)
{
switch (src_ext) {
case MO_UB:
Expand Down Expand Up @@ -417,6 +423,59 @@ tcg_out_movext(TCGContext *s, TCGType dst_type, TCGReg dst,
}
}

/* Minor variations on a theme, using a structure. */
static void tcg_out_movext1_new_src(TCGContext *s, const TCGMovExtend *i,
TCGReg src)
{
tcg_out_movext(s, i->dst_type, i->dst, i->src_type, i->src_ext, src);
}

static void tcg_out_movext1(TCGContext *s, const TCGMovExtend *i)
{
tcg_out_movext1_new_src(s, i, i->src);
}

/**
* tcg_out_movext2 -- move and extend two pair
* @s: tcg context
* @i1: first move description
* @i2: second move description
* @scratch: temporary register, or -1 for none
*
* As tcg_out_movext, for both @i1 and @i2, caring for overlap
* between the sources and destinations.
*/

static void __attribute__((unused))
tcg_out_movext2(TCGContext *s, const TCGMovExtend *i1,
const TCGMovExtend *i2, int scratch)
{
TCGReg src1 = i1->src;
TCGReg src2 = i2->src;

if (i1->dst != src2) {
tcg_out_movext1(s, i1);
tcg_out_movext1(s, i2);
return;
}
if (i2->dst == src1) {
TCGType src1_type = i1->src_type;
TCGType src2_type = i2->src_type;

if (tcg_out_xchg(s, MAX(src1_type, src2_type), src1, src2)) {
/* The data is now in the correct registers, now extend. */
src1 = i2->src;
src2 = i1->src;
} else {
tcg_debug_assert(scratch >= 0);
tcg_out_mov(s, src1_type, scratch, src1);
src1 = scratch;
}
}
tcg_out_movext1_new_src(s, i2, src2);
tcg_out_movext1_new_src(s, i1, src1);
}

#define C_PFX1(P, A) P##A
#define C_PFX2(P, A, B) P##A##_##B
#define C_PFX3(P, A, B, C) P##A##_##B##_##C
Expand Down

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