gallium: add PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER

It's required by the latest IO refactoring.

screen.rst explains it and it's not pretty. It can be argued that
finalize_nir shouldn't exist.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32175>

docs/gallium/screen.rst

@@ -653,6 +653,7 @@ The integer capabilities:
 * ``PIPE_CAP_SHADER_SUBGROUP_SUPPORTED_FEATURES``: Bitmask of shader subgroup features listed in :ext:`GL_KHR_shader_subgroup`.
 * ``PIPE_CAP_SHADER_SUBGROUP_QUAD_ALL_STAGES``: Whether shader subgroup quad operations are supported by shader stages other than fragment shader.
 * ``PIPE_CAP_MULTIVIEW``: Whether multiview rendering of array textures is supported. A return of ``1`` indicates support for OVR_multiview, and ``2`` additionally supports OVR_multiview2. 
+* ``PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER``: Whether `pipe_screen::finalize_nir` can be called in the GLSL linker before the NIR is stored in the shader cache. It's always called again after st/mesa adds code for shader variants. It must be 1 if the driver wants to report compile failures to the GLSL linker. It must be 0 if two consecutive `finalize_nir` calls on the same shader can break it, or if `finalize_nir` can't handle NIR that isn't fully lowered for the driver, or if `finalize_nir` breaks passes that st/mesa runs after it. Setting it to 1 is generally safe for drivers that expose nir_io_has_intrinsics and that don't enable any optional shader variants in st/mesa. Since it's difficult to support, any future refactoring can change it to 0.
 
 
 .. _pipe_capf:

src/gallium/auxiliary/util/u_screen.c

@@ -565,6 +565,7 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_SHADER_SUBGROUP_SUPPORTED_STAGES:
    case PIPE_CAP_SHADER_SUBGROUP_SUPPORTED_FEATURES:
    case PIPE_CAP_SHADER_SUBGROUP_QUAD_ALL_STAGES:
+   case PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER:
       return 0;
 
    default:

src/gallium/drivers/i915/i915_screen.c

@@ -413,6 +413,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_USER_VERTEX_BUFFERS:
    case PIPE_CAP_MIXED_COLOR_DEPTH_BITS:
    case PIPE_CAP_TGSI_TEXCOORD:
+   case PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER:
       return 1;
 
    case PIPE_CAP_TEXTURE_TRANSFER_MODES:

src/gallium/drivers/r300/r300_screen.c

@@ -130,6 +130,7 @@ static int r300_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
         case PIPE_CAP_ALLOW_MAPPED_BUFFERS_DURING_EXECUTION:
         case PIPE_CAP_LEGACY_MATH_RULES:
         case PIPE_CAP_TGSI_TEXCOORD:
+        case PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER:
             return 1;
 
         case PIPE_CAP_TEXTURE_TRANSFER_MODES:

src/gallium/drivers/radeonsi/si_get.c

@@ -178,6 +178,7 @@ static int si_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_NULL_TEXTURES:
    case PIPE_CAP_HAS_CONST_BW:
    case PIPE_CAP_CL_GL_SHARING:
+   case PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER:
       return 1;
 
    /* Tahiti and Verde only: reduction mode is unsupported due to a bug

src/gallium/drivers/zink/zink_screen.c

@@ -645,6 +645,7 @@ zink_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_MULTISAMPLE_Z_RESOLVE:
    case PIPE_CAP_ALLOW_GLTHREAD_BUFFER_SUBDATA_OPT:
    case PIPE_CAP_NIR_SAMPLERS_AS_DEREF:
+   case PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER:
       return 1;
 
    case PIPE_CAP_DRAW_VERTEX_STATE:

src/gallium/include/pipe/p_defines.h

@@ -987,6 +987,7 @@ enum pipe_cap
    PIPE_CAP_SHADER_SUBGROUP_SUPPORTED_FEATURES,
    PIPE_CAP_SHADER_SUBGROUP_QUAD_ALL_STAGES,
    PIPE_CAP_MULTIVIEW,
+   PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER,
    PIPE_CAP_LAST,
    /* XXX do not add caps after PIPE_CAP_LAST! */
 };

src/mesa/state_tracker/st_context.c

@@ -625,7 +625,8 @@ st_create_context_priv(struct gl_context *ctx, struct pipe_context *pipe,
       screen->get_param(screen, PIPE_CAP_CONDITIONAL_RENDER);
    st->lower_rect_tex =
       !screen->get_param(screen, PIPE_CAP_TEXRECT);
-   st->allow_st_finalize_nir_twice = screen->finalize_nir != NULL;
+   st->allow_st_finalize_nir_twice =
+      screen->get_param(screen, PIPE_CAP_CALL_FINALIZE_NIR_IN_LINKER);
 
    st->has_hw_atomics =
       screen->get_shader_param(screen, PIPE_SHADER_FRAGMENT,