Cache the Thread Local Base pointer type in the gdbarch

  gdb/ChangeLog:

2020-02-09  Hannes Domani  <ssbssa@yahoo.de>

	* windows-tdep.c (struct windows_gdbarch_data): Add tib_ptr_type.
	(windows_get_tlb_type): Use windows_gdbarch_data->tib_ptr_type.
---
 gdb/windows-tdep.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)
  

Hi,

On 2/9/20 1:41 PM, Hannes Domani via gdb-patches wrote:
> gdb/ChangeLog:
> 
> 2020-02-09  Hannes Domani  <ssbssa@yahoo.de>
> 
> 	* windows-tdep.c (struct windows_gdbarch_data): Add tib_ptr_type.
> 	(windows_get_tlb_type): Use windows_gdbarch_data->tib_ptr_type.
> ---
>   gdb/windows-tdep.c | 15 +++++++--------
>   1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/gdb/windows-tdep.c b/gdb/windows-tdep.c
> index 6eef476fb5..2efd2f0d7e 100644
> --- a/gdb/windows-tdep.c
> +++ b/gdb/windows-tdep.c
> @@ -162,6 +162,7 @@ static struct gdbarch_data *windows_gdbarch_data_handle;
>   struct windows_gdbarch_data
>   {
>     struct type *siginfo_type;
> +  struct type *tib_ptr_type;
>   };
>   
>   /* Allocate windows_gdbarch_data for an arch.  */

 From someone that doesn't know the inner workings of Windows, i was 
slightly confused with the change from tlb to tib. But i see what it is 
now. Maybe worth adding a comment mentioning what it is that you're caching.

> @@ -186,8 +187,7 @@ get_windows_gdbarch_data (struct gdbarch *gdbarch)
>   static struct type *
>   windows_get_tlb_type (struct gdbarch *gdbarch)
>   {
> -  static struct gdbarch *last_gdbarch = NULL;
> -  static struct type *last_tlb_type = NULL;
> +  struct windows_gdbarch_data *windows_gdbarch_data;
>     struct type *dword_ptr_type, *dword32_type, *void_ptr_type;
>     struct type *peb_ldr_type, *peb_ldr_ptr_type;
>     struct type *peb_type, *peb_ptr_type, *list_type;
> @@ -196,10 +196,10 @@ windows_get_tlb_type (struct gdbarch *gdbarch)
>     struct type *word_type, *wchar_type, *wchar_ptr_type;
>     struct type *uni_str_type, *rupp_type, *rupp_ptr_type;
>   
> -  /* Do not rebuild type if same gdbarch as last time.  */
> -  if (last_tlb_type && last_gdbarch == gdbarch)
> -    return last_tlb_type;
> -
> +  windows_gdbarch_data = get_windows_gdbarch_data (gdbarch);
> +  if (windows_gdbarch_data->tib_ptr_type != NULL)
> +    return windows_gdbarch_data->tib_ptr_type;
> +

NULL should be nullptr now that we've switched to C++, since we're 
patching this code up.

>     dword_ptr_type = arch_integer_type (gdbarch, gdbarch_ptr_bit (gdbarch),
>   				 1, "DWORD_PTR");
>     dword32_type = arch_integer_type (gdbarch, 32,
> @@ -369,8 +369,7 @@ windows_get_tlb_type (struct gdbarch *gdbarch)
>   			    NULL);
>     TYPE_TARGET_TYPE (tib_ptr_type) = tib_type;
>   
> -  last_tlb_type = tib_ptr_type;
> -  last_gdbarch = gdbarch;
> +  windows_gdbarch_data->tib_ptr_type = tib_ptr_type;
>   
>     return tib_ptr_type;
>   }
>