Re: [PATCH v4 05/43] tcg: Move tcg prologue pointer out of TCGContext

[Philippe Mathieu-Daudé]

On 12/14/20 3:02 PM, Richard Henderson wrote:
> This value is constant across all thread-local copies of TCGContext,
> so we might as well move it out of thread-local storage.
> 
> Use the correct function pointer type, and name the variable
> tcg_qemu_tb_exec, which means that we are able to remove the
> macro that does the casting.
> 
> Replace HAVE_TCG_QEMU_TB_EXEC with CONFIG_TCG_INTERPRETER,
> as this is somewhat clearer in intent.
> 
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  include/tcg/tcg.h | 9 ++++-----
>  tcg/tcg.c         | 9 ++++++++-
>  tcg/tci.c         | 3 ++-
>  3 files changed, 14 insertions(+), 7 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> 
> diff --git a/include/tcg/tcg.h b/include/tcg/tcg.h
> index 8ff9dad4ef..9cc412f90c 100644
> --- a/include/tcg/tcg.h
> +++ b/include/tcg/tcg.h
> @@ -621,7 +621,6 @@ struct TCGContext {
>         here, because there's too much arithmetic throughout that relies
>         on addition and subtraction working on bytes.  Rely on the GCC
>         extension that allows arithmetic on void*.  */
> -    void *code_gen_prologue;
>      void *code_gen_epilogue;
>      void *code_gen_buffer;
>      size_t code_gen_buffer_size;
> @@ -1222,11 +1221,11 @@ static inline unsigned get_mmuidx(TCGMemOpIdx oi)
>  #define TB_EXIT_IDXMAX    1
>  #define TB_EXIT_REQUESTED 3
>  
> -#ifdef HAVE_TCG_QEMU_TB_EXEC
> -uintptr_t tcg_qemu_tb_exec(CPUArchState *env, uint8_t *tb_ptr);
> +#ifdef CONFIG_TCG_INTERPRETER
> +uintptr_t tcg_qemu_tb_exec(CPUArchState *env, void *tb_ptr);
>  #else
> -# define tcg_qemu_tb_exec(env, tb_ptr) \
> -    ((uintptr_t (*)(void *, void *))tcg_ctx->code_gen_prologue)(env, tb_ptr)
> +typedef uintptr_t tcg_prologue_fn(CPUArchState *env, void *tb_ptr);
> +extern tcg_prologue_fn *tcg_qemu_tb_exec;
>  #endif
>  
>  void tcg_register_jit(void *buf, size_t buf_size);
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index 675334e844..67065c2ede 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -162,6 +162,10 @@ static TCGContext **tcg_ctxs;
>  static unsigned int n_tcg_ctxs;
>  TCGv_env cpu_env = 0;
>  
> +#ifndef CONFIG_TCG_INTERPRETER
> +tcg_prologue_fn *tcg_qemu_tb_exec;
> +#endif
> +
>  struct tcg_region_tree {
>      QemuMutex lock;
>      GTree *tree;
> @@ -1055,7 +1059,10 @@ void tcg_prologue_init(TCGContext *s)
>      s->code_ptr = buf0;
>      s->code_buf = buf0;
>      s->data_gen_ptr = NULL;
> -    s->code_gen_prologue = buf0;
> +
> +#ifndef CONFIG_TCG_INTERPRETER
> +    tcg_qemu_tb_exec = (tcg_prologue_fn *)buf0;
> +#endif
>  
>      /* Compute a high-water mark, at which we voluntarily flush the buffer
>         and start over.  The size here is arbitrary, significantly larger
> diff --git a/tcg/tci.c b/tcg/tci.c
> index 82039fd163..d996eb7cf8 100644
> --- a/tcg/tci.c
> +++ b/tcg/tci.c
> @@ -475,8 +475,9 @@ static bool tci_compare64(uint64_t u0, uint64_t u1, 
> TCGCond condition)
>  #endif
>  
>  /* Interpret pseudo code in tb. */
> -uintptr_t tcg_qemu_tb_exec(CPUArchState *env, uint8_t *tb_ptr)
> +uintptr_t tcg_qemu_tb_exec(CPUArchState *env, void *v_tb_ptr)
>  {
> +    uint8_t *tb_ptr = v_tb_ptr;
>      tcg_target_ulong regs[TCG_TARGET_NB_REGS];
>      long tcg_temps[CPU_TEMP_BUF_NLONGS];
>      uintptr_t sp_value = (uintptr_t)(tcg_temps + CPU_TEMP_BUF_NLONGS);
>