Commit 5bcebc25 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg-i386: Don't perform GETPC adjustment in TCG code 



Since we now perform it inside the helper, no need to do it here.
This also lets us perform a tail-call from the store slow path to
the helper.

Reviewed-by: default avatarAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent 0f842f8a

tcg/i386/tcg-target.c

+14 −19
Original line number Diff line number Diff line
@@ -1481,12 +1481,6 @@ static void add_qemu_ldst_label(TCGContext *s, 
    }

}



/* See the GETPC definition in include/exec/exec-all.h.  */

static inline uintptr_t do_getpc(uint8_t *raddr)

{

    return (uintptr_t)raddr - 1;

}



/*

 * Generate code for the slow path for a load at the end of block

 */
@@ -1520,14 +1514,14 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l) 
        tcg_out_sti(s, TCG_TYPE_I32, TCG_REG_ESP, ofs, l->mem_index);

        ofs += 4;



        tcg_out_sti(s, TCG_TYPE_I32, TCG_REG_ESP, ofs, do_getpc(l->raddr));

        tcg_out_sti(s, TCG_TYPE_I32, TCG_REG_ESP, ofs, (uintptr_t)l->raddr);

    } else {

        tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0);

        /* The second argument is already loaded with addrlo.  */

        tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[2],

                     l->mem_index);

        tcg_out_movi(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[3],

                     do_getpc(l->raddr));

                     (uintptr_t)l->raddr);

    }



    tcg_out_calli(s, (uintptr_t)qemu_ld_helpers[s_bits]);
@@ -1582,6 +1576,7 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) 
    int opc = l->opc;

    int s_bits = opc & 3;

    uint8_t **label_ptr = &l->label_ptr[0];

    TCGReg retaddr;



    /* resolve label address */

    *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4);
@@ -1614,10 +1609,10 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) 
        tcg_out_sti(s, TCG_TYPE_I32, TCG_REG_ESP, ofs, l->mem_index);

        ofs += 4;



        tcg_out_sti(s, TCG_TYPE_I32, TCG_REG_ESP, ofs, do_getpc(l->raddr));

        retaddr = TCG_REG_EAX;

        tcg_out_movi(s, TCG_TYPE_I32, retaddr, (uintptr_t)l->raddr);

        tcg_out_st(s, TCG_TYPE_I32, retaddr, TCG_REG_ESP, ofs);

    } else {

        uintptr_t pc;



        tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0);

        /* The second argument is already loaded with addrlo.  */

        tcg_out_mov(s, (opc == 3 ? TCG_TYPE_I64 : TCG_TYPE_I32),
@@ -1625,19 +1620,19 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) 
        tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3],

                     l->mem_index);



        pc = do_getpc(l->raddr);

        if (ARRAY_SIZE(tcg_target_call_iarg_regs) > 4) {

            tcg_out_movi(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[4], pc);

        } else if (pc == (int32_t)pc) {

            tcg_out_sti(s, TCG_TYPE_PTR, TCG_REG_ESP, 0, pc);

            retaddr = tcg_target_call_iarg_regs[4];

            tcg_out_movi(s, TCG_TYPE_PTR, retaddr, (uintptr_t)l->raddr);

        } else {

            tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_RAX, pc);

            tcg_out_st(s, TCG_TYPE_PTR, TCG_REG_RAX, TCG_REG_ESP, 0);

            retaddr = TCG_REG_RAX;

            tcg_out_movi(s, TCG_TYPE_PTR, retaddr, (uintptr_t)l->raddr);

            tcg_out_st(s, TCG_TYPE_PTR, retaddr, TCG_REG_ESP, 0);

        }

    }



    tcg_out_calli(s, (uintptr_t)qemu_st_helpers[s_bits]);

    tcg_out_jmp(s, (uintptr_t)l->raddr);

    /* "Tail call" to the helper, with the return address back inline.  */

    tcg_out_push(s, retaddr);

    tcg_out_jmp(s, (uintptr_t)qemu_st_helpers[s_bits]);

}



/*