[for-next,3/8] tcg-i386: Tidy qemu_ld/st slow path

Use existing stack space for arguments; don't push/pop.
Use less ifdefs and more C ifs.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/i386/tcg-target.c | 159 +++++++++++++++++++++-----------------------------
 1 file changed, 68 insertions(+), 91 deletions(-)

On Mon, Aug 05, 2013 at 08:07:20AM -1000, Richard Henderson wrote:
> Use existing stack space for arguments; don't push/pop.
> Use less ifdefs and more C ifs.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/i386/tcg-target.c | 159 +++++++++++++++++++++-----------------------------
>  1 file changed, 68 insertions(+), 91 deletions(-)
> 
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index 456bd9e..8addfa1 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -1461,22 +1461,12 @@ static void add_qemu_ldst_label(TCGContext *s,
>  /*
>   * Generate code for the slow path for a load at the end of block
>   */
> -static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
> +static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
>  {
> -    int s_bits;
> -    int opc = label->opc;
> -    int mem_index = label->mem_index;
> -#if TCG_TARGET_REG_BITS == 32
> -    int stack_adjust;
> -    int addrlo_reg = label->addrlo_reg;
> -    int addrhi_reg = label->addrhi_reg;
> -#endif
> -    int data_reg = label->datalo_reg;
> -    int data_reg2 = label->datahi_reg;
> -    uint8_t *raddr = label->raddr;
> -    uint8_t **label_ptr = &label->label_ptr[0];
> -
> -    s_bits = opc & 3;
> +    int opc = l->opc;
> +    int s_bits = opc & 3;
> +    TCGReg data_reg;
> +    uint8_t **label_ptr = &l->label_ptr[0];
>  
>      /* resolve label address */
>      *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4);
> @@ -1484,22 +1474,28 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>          *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4);
>      }
>  
> -#if TCG_TARGET_REG_BITS == 32
> -    tcg_out_pushi(s, mem_index);
> -    stack_adjust = 4;
> -    if (TARGET_LONG_BITS == 64) {
> -        tcg_out_push(s, addrhi_reg);
> -        stack_adjust += 4;
> +    if (TCG_TARGET_REG_BITS == 32) {
> +        int ofs = 0;
> +
> +        tcg_out_st(s, TCG_TYPE_PTR, TCG_AREG0, TCG_REG_ESP, ofs);
> +        ofs += 4;
> +
> +        tcg_out_st(s, TCG_TYPE_I32, l->addrlo_reg, TCG_REG_ESP, ofs);
> +        ofs += 4;
> +
> +        if (TARGET_LONG_BITS == 64) {
> +            tcg_out_st(s, TCG_TYPE_I32, l->addrhi_reg, TCG_REG_ESP, ofs);
> +            ofs += 4;
> +        }
> +
> +        tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_EAX, l->mem_index);
> +        tcg_out_st(s, TCG_TYPE_I32, TCG_REG_EAX, TCG_REG_ESP, ofs);

The same way the previous code was able to push an immediate, it should
be possible to directly store an immediate value here:

            tcg_out_modrm_offset(s, OPC_MOVL_EvIz, 0, TCG_REG_ESP, ofs);
            tcg_out32(s, l->mem_index);

> +    } else {
> +        tcg_out_mov(s, TCG_TYPE_I64, 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_push(s, addrlo_reg);
> -    stack_adjust += 4;
> -    tcg_out_push(s, TCG_AREG0);
> -    stack_adjust += 4;
> -#else
> -    tcg_out_mov(s, TCG_TYPE_I64, 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], mem_index);
> -#endif
>  
>      /* Code generation of qemu_ld/st's slow path calling MMU helper
>  
> @@ -1518,18 +1514,10 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>      tcg_out8(s, 5);
>      /* Dummy backward jump having information of fast path'pc for MMU helpers */
>      tcg_out8(s, OPC_JMP_long);
> -    *(int32_t *)s->code_ptr = (int32_t)(raddr - s->code_ptr - 4);
> +    *(int32_t *)s->code_ptr = (int32_t)(l->raddr - s->code_ptr - 4);
>      s->code_ptr += 4;
>  
> -#if TCG_TARGET_REG_BITS == 32
> -    if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
> -        /* Pop and discard.  This is 2 bytes smaller than the add.  */
> -        tcg_out_pop(s, TCG_REG_ECX);
> -    } else if (stack_adjust != 0) {
> -        tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
> -    }
> -#endif
> -
> +    data_reg = l->datalo_reg;
>      switch(opc) {
>      case 0 | 4:
>          tcg_out_ext8s(s, data_reg, TCG_REG_EAX, P_REXW);
> @@ -1557,10 +1545,10 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>          } else 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, data_reg2, TCG_REG_EAX);
> +            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, data_reg2, TCG_REG_EDX);
> +            tcg_out_mov(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_EDX);
>          }
>          break;
>      default:
> @@ -1568,28 +1556,17 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>      }
>  
>      /* Jump to the code corresponding to next IR of qemu_st */
> -    tcg_out_jmp(s, (tcg_target_long)raddr);
> +    tcg_out_jmp(s, (tcg_target_long)l->raddr);
>  }
>  
>  /*
>   * Generate code for the slow path for a store at the end of block
>   */
> -static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
> +static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
>  {
> -    int s_bits;
> -    int stack_adjust;
> -    int opc = label->opc;
> -    int mem_index = label->mem_index;
> -    int data_reg = label->datalo_reg;
> -#if TCG_TARGET_REG_BITS == 32
> -    int data_reg2 = label->datahi_reg;
> -    int addrlo_reg = label->addrlo_reg;
> -    int addrhi_reg = label->addrhi_reg;
> -#endif
> -    uint8_t *raddr = label->raddr;
> -    uint8_t **label_ptr = &label->label_ptr[0];
> -
> -    s_bits = opc & 3;
> +    int opc = l->opc;
> +    int s_bits = opc & 3;
> +    uint8_t **label_ptr = &l->label_ptr[0];
>  
>      /* resolve label address */
>      *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4);
> @@ -1597,31 +1574,38 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>          *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4);
>      }
>  
> -#if TCG_TARGET_REG_BITS == 32
> -    tcg_out_pushi(s, mem_index);
> -    stack_adjust = 4;
> -    if (opc == 3) {
> -        tcg_out_push(s, data_reg2);
> -        stack_adjust += 4;
> -    }
> -    tcg_out_push(s, data_reg);
> -    stack_adjust += 4;
> -    if (TARGET_LONG_BITS == 64) {
> -        tcg_out_push(s, addrhi_reg);
> -        stack_adjust += 4;
> +    if (TCG_TARGET_REG_BITS == 32) {
> +        int ofs = 0;
> +
> +        tcg_out_st(s, TCG_TYPE_PTR, TCG_AREG0, TCG_REG_ESP, ofs);
> +        ofs += 4;
> +
> +        tcg_out_st(s, TCG_TYPE_I32, l->addrlo_reg, TCG_REG_ESP, ofs);
> +        ofs += 4;
> +
> +        if (TARGET_LONG_BITS == 64) {
> +            tcg_out_st(s, TCG_TYPE_I32, l->addrhi_reg, TCG_REG_ESP, ofs);
> +            ofs += 4;
> +        }
> +
> +        tcg_out_st(s, TCG_TYPE_I32, l->datalo_reg, TCG_REG_ESP, ofs);
> +        ofs += 4;
> +
> +        if (opc == 3) {
> +            tcg_out_st(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_ESP, ofs);
> +            ofs += 4;
> +        }
> +
> +        tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_EAX, l->mem_index);
> +        tcg_out_st(s, TCG_TYPE_I32, TCG_REG_EAX, TCG_REG_ESP, ofs);

Same there.

> +    } else {
> +        tcg_out_mov(s, TCG_TYPE_I64, 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),
> +                    tcg_target_call_iarg_regs[2], l->datalo_reg);
> +        tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3],
> +                     l->mem_index);
>      }
> -    tcg_out_push(s, addrlo_reg);
> -    stack_adjust += 4;
> -    tcg_out_push(s, TCG_AREG0);
> -    stack_adjust += 4;
> -#else
> -    tcg_out_mov(s, TCG_TYPE_I64, 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),
> -                tcg_target_call_iarg_regs[2], data_reg);
> -    tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3], mem_index);
> -    stack_adjust = 0;
> -#endif
>  
>      /* Code generation of qemu_ld/st's slow path calling MMU helper
>  
> @@ -1640,18 +1624,11 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
>      tcg_out8(s, 5);
>      /* Dummy backward jump having information of fast path'pc for MMU helpers */
>      tcg_out8(s, OPC_JMP_long);
> -    *(int32_t *)s->code_ptr = (int32_t)(raddr - s->code_ptr - 4);
> +    *(int32_t *)s->code_ptr = (int32_t)(l->raddr - s->code_ptr - 4);
>      s->code_ptr += 4;
>  
> -    if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
> -        /* Pop and discard.  This is 2 bytes smaller than the add.  */
> -        tcg_out_pop(s, TCG_REG_ECX);
> -    } else if (stack_adjust != 0) {
> -        tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
> -    }
> -
>      /* Jump to the code corresponding to next IR of qemu_st */
> -    tcg_out_jmp(s, (tcg_target_long)raddr);
> +    tcg_out_jmp(s, (tcg_target_long)l->raddr);
>  }
>  

The remaining looks fine to me.