[Mesa-dev] [PATCH] glsl: Allow compatibility shaders with MESA_GL_VERSION_OVERRIDE=...

[Ilia Mirkin]

I wonder if it'd be beneficial to adjust the
_mesa_glsl_process_extension logic to force api = API_OPENGL_COMPAT
when compat_shader is set. For now, ctx->API has to match, so it
should never matter, but perhaps in the future, this would be a tricky
little bug to track down.

On Tue, Jan 31, 2017 at 7:20 PM, Matt Turner <mattst88 at gmail.com> wrote:
> Previously if you used MESA_GL_VERSION_OVERRIDE=3.3COMPAT, Mesa exposed
> an OpenGL 3.3 compatibility profile context (with various unimplemented
> features and bugs), but still refused to compile shaders with
>
>    #version 330 compatibility
>
> This patch simply adds a small bit of plumbing to let that through.
>
> Of course the same caveats apply: compatibility profile is still not
> supported (and will not be supported), so there are no guarantees that
> anything will work.
> ---
>  src/compiler/glsl/builtin_types.cpp      |  2 +-
>  src/compiler/glsl/builtin_variables.cpp  |  2 +-
>  src/compiler/glsl/glsl_parser_extras.cpp | 13 +++++++++++--
>  src/compiler/glsl/glsl_parser_extras.h   |  1 +
>  4 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/src/compiler/glsl/builtin_types.cpp b/src/compiler/glsl/builtin_types.cpp
> index a63d736..cae972b 100644
> --- a/src/compiler/glsl/builtin_types.cpp
> +++ b/src/compiler/glsl/builtin_types.cpp
> @@ -288,7 +288,7 @@ _mesa_glsl_initialize_types(struct _mesa_glsl_parse_state *state)
>     /* Add deprecated structure types.  While these were deprecated in 1.30,
>      * they're still present.  We've removed them in 1.40+ (OpenGL 3.1+).
>      */
> -   if (!state->es_shader && state->language_version < 140) {
> +   if (state->compat_shader) {
>        for (unsigned i = 0; i < ARRAY_SIZE(deprecated_types); i++) {
>           add_type(symbols, deprecated_types[i]);
>        }
> diff --git a/src/compiler/glsl/builtin_variables.cpp b/src/compiler/glsl/builtin_variables.cpp
> index 4eb275e..be593e9 100644
> --- a/src/compiler/glsl/builtin_variables.cpp
> +++ b/src/compiler/glsl/builtin_variables.cpp
> @@ -444,7 +444,7 @@ private:
>  builtin_variable_generator::builtin_variable_generator(
>     exec_list *instructions, struct _mesa_glsl_parse_state *state)
>     : instructions(instructions), state(state), symtab(state->symbols),
> -     compatibility(!state->is_version(140, 100)),
> +     compatibility(state->compat_shader || !state->is_version(140, 100)),
>       bool_t(glsl_type::bool_type), int_t(glsl_type::int_type),
>       uint_t(glsl_type::uint_type),
>       float_t(glsl_type::float_type), vec2_t(glsl_type::vec2_type),
> diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
> index e888090..1e47d8c 100644
> --- a/src/compiler/glsl/glsl_parser_extras.cpp
> +++ b/src/compiler/glsl/glsl_parser_extras.cpp
> @@ -82,6 +82,7 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct gl_context *_ctx,
>     this->forced_language_version = ctx->Const.ForceGLSLVersion;
>     this->zero_init = ctx->Const.GLSLZeroInit;
>     this->gl_version = 20;
> +   this->compat_shader = true;
>     this->es_shader = false;
>     this->ARB_texture_rectangle_enable = true;
>
> @@ -369,6 +370,7 @@ _mesa_glsl_parse_state::process_version_directive(YYLTYPE *locp, int version,
>                                                    const char *ident)
>  {
>     bool es_token_present = false;
> +   bool compat_token_present = false;
>     if (ident) {
>        if (strcmp(ident, "es") == 0) {
>           es_token_present = true;
> @@ -378,8 +380,12 @@ _mesa_glsl_parse_state::process_version_directive(YYLTYPE *locp, int version,
>               * a core profile shader since that's the only profile we support.
>               */
>           } else if (strcmp(ident, "compatibility") == 0) {
> -            _mesa_glsl_error(locp, this,
> -                             "the compatibility profile is not supported");
> +            compat_token_present = true;
> +
> +            if (this->ctx->API != API_OPENGL_COMPAT) {
> +               _mesa_glsl_error(locp, this,
> +                                "the compatibility profile is not supported");
> +            }
>           } else {
>              _mesa_glsl_error(locp, this,
>                               "\"%s\" is not a valid shading language profile; "
> @@ -411,6 +417,9 @@ _mesa_glsl_parse_state::process_version_directive(YYLTYPE *locp, int version,
>     else
>        this->language_version = version;
>
> +   this->compat_shader = compat_token_present ||
> +                         (!this->es_shader && this->language_version < 140);
> +
>     bool supported = false;
>     for (unsigned i = 0; i < this->num_supported_versions; i++) {
>        if (this->supported_versions[i].ver == this->language_version
> diff --git a/src/compiler/glsl/glsl_parser_extras.h b/src/compiler/glsl/glsl_parser_extras.h
> index 424cab5..66a954f 100644
> --- a/src/compiler/glsl/glsl_parser_extras.h
> +++ b/src/compiler/glsl/glsl_parser_extras.h
> @@ -348,6 +348,7 @@ struct _mesa_glsl_parse_state {
>     } supported_versions[16];
>
>     bool es_shader;
> +   bool compat_shader;
>     unsigned language_version;
>     unsigned forced_language_version;
>     bool zero_init;
> --
> 2.10.2
>
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