Re: [Qemu-devel] [PATCH v3 13/26] tcg-aarch64: Implement tcg_register_jit

[Claudio Fontana <claudio.fontana@huawei.com>]

On 03.04.2014 21:56, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 84 +++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 69 insertions(+), 15 deletions(-)
> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index 5cffe50..4414bd1 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -1848,24 +1848,29 @@ static void tcg_target_init(TCGContext *s)
>      tcg_add_target_add_op_defs(aarch64_op_defs);
>  }
>  
> +/* Saving pairs: (X19, X20) .. (X27, X28), (X29(fp), X30(lr)).  */
> +#define PUSH_SIZE  ((30 - 19 + 1) * 8)
> +
> +#define FRAME_SIZE \
> +    ((PUSH_SIZE \
> +      + TCG_STATIC_CALL_ARGS_SIZE \
> +      + CPU_TEMP_BUF_NLONGS * sizeof(long) \
> +      + TCG_TARGET_STACK_ALIGN - 1) \
> +     & ~(TCG_TARGET_STACK_ALIGN - 1))
> +
> +/* We're expecting a 2 byte uleb128 encoded value.  */
> +QEMU_BUILD_BUG_ON(FRAME_SIZE >= (1 << 14));
> +
> +/* We're expecting to use a single ADDI insn.  */
> +QEMU_BUILD_BUG_ON(FRAME_SIZE - PUSH_SIZE > 0xfff);
> +
>  static void tcg_target_qemu_prologue(TCGContext *s)
>  {
> -    /* NB: frame sizes are in 16 byte stack units! */
> -    int frame_size_callee_saved, frame_size_tcg_locals;
>      TCGReg r;
>  
> -    /* save pairs             (FP, LR) and (X19, X20) .. (X27, X28) */
> -    frame_size_callee_saved = 16 + (TCG_REG_X28 - TCG_REG_X19 + 1) * 8;
> -
> -    /* frame size requirement for TCG local variables */
> -    frame_size_tcg_locals = TCG_STATIC_CALL_ARGS_SIZE
> -        + CPU_TEMP_BUF_NLONGS * sizeof(long)
> -        + (TCG_TARGET_STACK_ALIGN - 1);
> -    frame_size_tcg_locals &= ~(TCG_TARGET_STACK_ALIGN - 1);
> -
>      /* Push (FP, LR) and allocate space for all saved registers.  */
>      tcg_out_insn(s, 3314, STP, TCG_REG_FP, TCG_REG_LR,
> -                 TCG_REG_SP, -frame_size_callee_saved, 1, 1);
> +                 TCG_REG_SP, -PUSH_SIZE, 1, 1);
>  
>      /* Set up frame pointer for canonical unwinding.  */
>      tcg_out_movr_sp(s, TCG_TYPE_I64, TCG_REG_FP, TCG_REG_SP);
> @@ -1878,7 +1883,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
>  
>      /* Make stack space for TCG locals.  */
>      tcg_out_insn(s, 3401, SUBI, TCG_TYPE_I64, TCG_REG_SP, TCG_REG_SP,
> -                 frame_size_tcg_locals);
> +                 FRAME_SIZE - PUSH_SIZE);
>  
>      /* Inform TCG about how to find TCG locals with register, offset, size.  */
>      tcg_set_frame(s, TCG_REG_SP, TCG_STATIC_CALL_ARGS_SIZE,
> @@ -1898,7 +1903,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
>  
>      /* Remove TCG locals stack space.  */
>      tcg_out_insn(s, 3401, ADDI, TCG_TYPE_I64, TCG_REG_SP, TCG_REG_SP,
> -                 frame_size_tcg_locals);
> +                 FRAME_SIZE - PUSH_SIZE);
>  
>      /* Restore registers x19..x28.  */
>      for (r = TCG_REG_X19; r <= TCG_REG_X27; r += 2) {
> @@ -1908,6 +1913,55 @@ static void tcg_target_qemu_prologue(TCGContext *s)
>  
>      /* Pop (FP, LR), restore SP to previous frame.  */
>      tcg_out_insn(s, 3314, LDP, TCG_REG_FP, TCG_REG_LR,
> -                 TCG_REG_SP, frame_size_callee_saved, 0, 1);
> +                 TCG_REG_SP, PUSH_SIZE, 0, 1);
>      tcg_out_insn(s, 3207, RET, TCG_REG_LR);
>  }
> +
> +typedef struct {
> +    DebugFrameCIE cie;
> +    DebugFrameFDEHeader fde;
> +    uint8_t fde_def_cfa[4];
> +    uint8_t fde_reg_ofs[24];
> +} DebugFrame;
> +
> +#define ELF_HOST_MACHINE EM_AARCH64
> +
> +static DebugFrame debug_frame = {
> +    .cie.len = sizeof(DebugFrameCIE)-4, /* length after .len member */
> +    .cie.id = -1,
> +    .cie.version = 1,
> +    .cie.code_align = 1,
> +    .cie.data_align = 0x78,             /* sleb128 -8 */
> +    .cie.return_column = TCG_REG_LR,
> +
> +    /* Total FDE size does not include the "len" member.  */
> +    .fde.len = sizeof(DebugFrame) - offsetof(DebugFrame, fde.cie_offset),
> +
> +    .fde_def_cfa = {
> +        12, TCG_REG_SP,                 /* DW_CFA_def_cfa sp, ... */
> +        (FRAME_SIZE & 0x7f) | 0x80,     /* ... uleb128 FRAME_SIZE */
> +        (FRAME_SIZE >> 7)
> +    },
> +    .fde_reg_ofs = {
> +        0x80 + 28, 1,                   /* DW_CFA_offset, x28,  -8 */
> +        0x80 + 27, 2,                   /* DW_CFA_offset, x27, -16 */
> +        0x80 + 26, 3,                   /* DW_CFA_offset, x26, -24 */
> +        0x80 + 25, 4,                   /* DW_CFA_offset, x25, -32 */
> +        0x80 + 24, 5,                   /* DW_CFA_offset, x24, -40 */
> +        0x80 + 23, 6,                   /* DW_CFA_offset, x23, -48 */
> +        0x80 + 22, 7,                   /* DW_CFA_offset, x22, -56 */
> +        0x80 + 21, 8,                   /* DW_CFA_offset, x21, -64 */
> +        0x80 + 20, 9,                   /* DW_CFA_offset, x20, -72 */
> +        0x80 + 19, 10,                  /* DW_CFA_offset, x1p, -80 */
> +        0x80 + 30, 11,                  /* DW_CFA_offset,  lr, -88 */
> +        0x80 + 29, 12,                  /* DW_CFA_offset,  fp, -96 */
> +    }
> +};
> +
> +void tcg_register_jit(void *buf, size_t buf_size)
> +{
> +    debug_frame.fde.func_start = (intptr_t)buf;
> +    debug_frame.fde.func_len = buf_size;
> +
> +    tcg_register_jit_int(buf, buf_size, &debug_frame, sizeof(debug_frame));
> +}
> 

Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>