[Mesa-dev] [PATCH V2 3/3] st/mesa: don't mark the program as in cache_fallback when there is cache miss

[Timothy Arceri]

When we fallback currently the gl_program objects are re-allocated.

This is likely to change when the i965 cache lands, but for now
this fixes a crash when using MESA_GLSL=cache_fb. This env var
simulates the fallback path taken when a tgsi cache item doesn't
exist due to being evicted previously or some kind of error.

Unlike i965 we are always falling back at link time so it's safe to
just re-allocate everything. We will be unnecessarily freeing and
re-allocate a bunch of things here but it's probably not a huge deal,
and can be changed when the i965 code lands.

Fixes: 0e9991f957e2 ("glsl: don't reference shader prog data during cache fallback")

---
 src/compiler/glsl/shader_cache.cpp       | 2 +-
 src/mesa/main/mtypes.h                   | 2 ++
 src/mesa/state_tracker/st_shader_cache.c | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/compiler/glsl/shader_cache.cpp b/src/compiler/glsl/shader_cache.cpp
index 800d3a2..dd56501 100644
--- a/src/compiler/glsl/shader_cache.cpp
+++ b/src/compiler/glsl/shader_cache.cpp
@@ -1285,21 +1285,21 @@ bool
 shader_cache_read_program_metadata(struct gl_context *ctx,
                                    struct gl_shader_program *prog)
 {
    /* Fixed function programs generated by Mesa are not cached. So don't
     * try to read metadata for them from the cache.
     */
    if (prog->Name == 0)
       return false;
 
    struct disk_cache *cache = ctx->Cache;
-   if (!cache || prog->data->cache_fallback)
+   if (!cache || prog->data->cache_fallback || prog->data->skip_cache)
       return false;
 
    /* Include bindings when creating sha1. These bindings change the resulting
     * binary so they are just as important as the shader source.
     */
    char *buf = ralloc_strdup(NULL, "vb: ");
    prog->AttributeBindings->iterate(create_binding_str, &buf);
    ralloc_strcat(&buf, "fb: ");
    prog->FragDataBindings->iterate(create_binding_str, &buf);
    ralloc_strcat(&buf, "fbi: ");
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 941311b..9ca4bb8 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2807,20 +2807,22 @@ struct gl_shader_program_data
 
    struct gl_active_atomic_buffer *AtomicBuffers;
    unsigned NumAtomicBuffers;
 
    /* Shader cache variables used during restore */
    unsigned NumUniformDataSlots;
    union gl_constant_value *UniformDataSlots;
 
    bool cache_fallback;
 
+   bool skip_cache;
+
    /** List of all active resources after linking. */
    struct gl_program_resource *ProgramResourceList;
    unsigned NumProgramResourceList;
 
    enum gl_link_status LinkStatus;   /**< GL_LINK_STATUS */
    GLboolean Validated;
    GLchar *InfoLog;
 
    unsigned Version;       /**< GLSL version used for linking */
 
diff --git a/src/mesa/state_tracker/st_shader_cache.c b/src/mesa/state_tracker/st_shader_cache.c
index 45438e5..31c3430 100644
--- a/src/mesa/state_tracker/st_shader_cache.c
+++ b/src/mesa/state_tracker/st_shader_cache.c
@@ -384,15 +384,15 @@ st_load_tgsi_from_disk_cache(struct gl_context *ctx,
 fallback_recompile:
    free(buffer);
 
    if (ctx->_Shader->Flags & GLSL_CACHE_INFO)
       fprintf(stderr, "TGSI cache falling back to recompile.\n");
 
    for (unsigned i = 0; i < prog->NumShaders; i++) {
       _mesa_glsl_compile_shader(ctx, prog->Shaders[i], false, false, true);
    }
 
-   prog->data->cache_fallback = true;
+   prog->data->skip_cache = true;
    _mesa_glsl_link_shader(ctx, prog);
 
    return true;
 }
-- 
2.9.4