[Mesa-dev] [PATCH 2/2] glsl: update default precision qualifiers when they are set in the shader

[Timothy Arceri]

On Thu, 2016-10-20 at 12:39 +0200, Samuel Iglesias Gonsálvez wrote:
> For that, we use gls_symbol_table::set_default_precision_qualifier()
> that
> can update an existing definition or add a new one if it doesn't
> exist.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97804
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>

Hi Samuel,

It looks like the parser pushes and pops scope of the symbol table so
these changes should work. However it would be nice to see some piglit
tests for this before landing these patches.

> ---
>  src/compiler/glsl/ast_to_hir.cpp        |  2 +-
>  src/compiler/glsl/glsl_symbol_table.cpp | 15 +++++++++++++++
>  src/compiler/glsl/glsl_symbol_table.h   |  2 ++
>  3 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/src/compiler/glsl/ast_to_hir.cpp
> b/src/compiler/glsl/ast_to_hir.cpp
> index 6e2f253..cc50ff8 100644
> --- a/src/compiler/glsl/ast_to_hir.cpp
> +++ b/src/compiler/glsl/ast_to_hir.cpp
> @@ -6559,7 +6559,7 @@ ast_type_specifier::hir(exec_list
> *instructions,
>            * is a slight abuse of the symbol table, but it has the
> semantics
>            * that we want.
>            */
> -         state->symbols->add_default_precision_qualifier(this-
> >type_name,
> +         state->symbols->set_default_precision_qualifier(this-
> >type_name,
>                                                           this-
> >default_precision);
>        }
>  
> diff --git a/src/compiler/glsl/glsl_symbol_table.cpp
> b/src/compiler/glsl/glsl_symbol_table.cpp
> index 6d7baad..11e5c00 100644
> --- a/src/compiler/glsl/glsl_symbol_table.cpp
> +++ b/src/compiler/glsl/glsl_symbol_table.cpp
> @@ -258,6 +258,21 @@ int
> glsl_symbol_table::get_default_precision_qualifier(const char
> *type_name)
>     return entry->a->default_precision;
>  }
>  
> +bool glsl_symbol_table::set_default_precision_qualifier(const char
> *type_name,
> +                                                        int
> precision)
> +{
> +   char *name = ralloc_asprintf(mem_ctx, "#default_precision_%s",
> type_name);
> +   symbol_table_entry *entry = get_entry(name);
> +   if (!entry)
> +      return add_default_precision_qualifier(type_name, precision);

I think I would rather just see this completely
replace add_default_precision_qualifier() rather than duplicating a
bunch of code. What do you think? I don't think avoiding
the get_entry() call saves us much.

> +
> +   ast_type_specifier *default_specifier = new(mem_ctx)
> ast_type_specifier(name);
> +   default_specifier->default_precision = precision;
> +
> +   entry = new(mem_ctx) symbol_table_entry(default_specifier);
> +   return _mesa_symbol_table_replace_symbol(table, -1, name, entry)
> == 0;
> +}
> +
>  symbol_table_entry *glsl_symbol_table::get_entry(const char *name)
>  {
>     return (symbol_table_entry *)
> diff --git a/src/compiler/glsl/glsl_symbol_table.h
> b/src/compiler/glsl/glsl_symbol_table.h
> index 2f94d4c..69a6912 100644
> --- a/src/compiler/glsl/glsl_symbol_table.h
> +++ b/src/compiler/glsl/glsl_symbol_table.h
> @@ -90,6 +90,8 @@ struct glsl_symbol_table {
>     const glsl_type *get_interface(const char *name,
>                                    enum ir_variable_mode mode);
>     int get_default_precision_qualifier(const char *type_name);
> +   bool set_default_precision_qualifier(const char *type_name, int
> precision);
> +
>     /*@}*/
>  
>     /**