llvmpipe: overhaul fs/cs variant keys to be simpler.

These currently always had one sampler state embedded, but got messy
when images was 1 and samplers was 0.

This should fix some undefined reads seen

Fixes: e639e311a1 ("llvmpipe/cs: overhaul cs variant key state.")
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13012>

src/gallium/drivers/llvmpipe/lp_linear.c

@@ -175,7 +175,7 @@ lp_fs_linear_run(const struct lp_rast_state *state,
 
       if (!lp_linear_init_sampler(&samp[i],
                                   tex_info,
-                                  &variant->key.samplers[unit],
+                                  lp_fs_variant_key_sampler_idx(&variant->key, unit),
                                   &state->jit_context.textures[unit],
                                   x, y, width, height,
                                   a0, dadx, dady)) {
@@ -315,7 +315,8 @@ lp_linear_check_variant(struct lp_fragment_shader_variant *variant)
          goto fail;
       }
 
-      if (!lp_linear_check_sampler(&key->samplers[unit], tex_info)) {
+      struct lp_sampler_static_state *samp = lp_fs_variant_key_sampler_idx(key, unit);
+      if (!lp_linear_check_sampler(samp, tex_info)) {
          if (LP_DEBUG & DEBUG_LINEAR)
             debug_printf(" -- samp[%d]: check_sampler failed\n", i);
          goto fail;

src/gallium/drivers/llvmpipe/lp_linear_fastpath.c

@@ -199,11 +199,15 @@ lp_linear_purple(const struct lp_rast_state *state,
 boolean
 lp_linear_check_fastpath(struct lp_fragment_shader_variant *variant)
 {
-   enum pipe_format tex_format = variant->key.samplers[0].texture_state.format;
+   struct lp_sampler_static_state *samp0 = lp_fs_variant_key_sampler_idx(&variant->key, 0);
 
+   if (!samp0)
+      return false;
+
+   enum pipe_format tex_format = samp0->texture_state.format;
    if (variant->shader->kind == LP_FS_KIND_BLIT_RGBA &&
        tex_format == PIPE_FORMAT_B8G8R8A8_UNORM &&
-       is_nearest_clamp_sampler(&variant->key.samplers[0]) &&
+       is_nearest_clamp_sampler(samp0) &&
        variant->opaque) {
       variant->jit_linear_blit             = lp_linear_blit_rgba_blit;
    }
@@ -212,7 +216,7 @@ lp_linear_check_fastpath(struct lp_fragment_shader_variant *variant)
        variant->opaque &&
        (tex_format == PIPE_FORMAT_B8G8R8A8_UNORM ||
         tex_format == PIPE_FORMAT_B8G8R8X8_UNORM) &&
-       is_nearest_clamp_sampler(&variant->key.samplers[0])) {
+       is_nearest_clamp_sampler(samp0)) {
       variant->jit_linear_blit             = lp_linear_blit_rgb1_blit;
    }
 

src/gallium/drivers/llvmpipe/lp_setup_rect.c

@@ -173,8 +173,10 @@ lp_setup_is_blit(const struct lp_setup_context *setup,
        * texture filtering.
        */
 
-      assert(variant->key.samplers[0].sampler_state.min_img_filter == PIPE_TEX_FILTER_NEAREST);
+      ASSERTED struct lp_sampler_static_state *samp0 = lp_fs_variant_key_sampler_idx(&variant->key, 0);
-      assert(variant->key.samplers[0].sampler_state.mag_img_filter == PIPE_TEX_FILTER_NEAREST);
+      assert(samp0);
+      assert(samp0->sampler_state.min_img_filter == PIPE_TEX_FILTER_NEAREST);
+      assert(samp0->sampler_state.mag_img_filter == PIPE_TEX_FILTER_NEAREST);
 
       /*
        * Check for 1:1 match of texels to dest pixels

src/gallium/drivers/llvmpipe/lp_state_cs.c

@@ -179,7 +179,7 @@ generate_compute(struct llvmpipe_context *lp,
    builder = gallivm->builder;
    assert(builder);
    LLVMPositionBuilderAtEnd(builder, block);
-   sampler = lp_llvm_sampler_soa_create(key->samplers, key->nr_samplers);
+   sampler = lp_llvm_sampler_soa_create(lp_cs_variant_key_samplers(key), key->nr_samplers);
    image = lp_llvm_image_soa_create(lp_cs_variant_key_images(key), key->nr_images);
 
    struct lp_build_loop_state loop_state[4];
@@ -578,7 +578,7 @@ make_variant_key(struct llvmpipe_context *lp,
    int i;
    struct lp_compute_shader_variant_key *key;
    key = (struct lp_compute_shader_variant_key *)store;
-   memset(key, 0, offsetof(struct lp_compute_shader_variant_key, samplers[1]));
+   memset(key, 0, sizeof(*key));
 
    /* This value will be the same for all the variants of a given shader:
     */
@@ -586,7 +586,9 @@ make_variant_key(struct llvmpipe_context *lp,
 
    struct lp_sampler_static_state *cs_sampler;
 
-   cs_sampler = key->samplers;
+   cs_sampler = lp_cs_variant_key_samplers(key);
+
+   memset(cs_sampler, 0, MAX2(key->nr_samplers, key->nr_sampler_views) * sizeof *cs_sampler);
    for(i = 0; i < key->nr_samplers; ++i) {
       if(shader->info.base.file_mask[TGSI_FILE_SAMPLER] & (1 << i)) {
          lp_sampler_static_sampler_state(&cs_sampler[i].sampler_state,
@@ -642,7 +644,8 @@ dump_cs_variant_key(const struct lp_compute_shader_variant_key *key)
    debug_printf("cs variant %p:\n", (void *) key);
 
    for (i = 0; i < key->nr_samplers; ++i) {
-      const struct lp_static_sampler_state *sampler = &key->samplers[i].sampler_state;
+      const struct lp_sampler_static_state *samplers = lp_cs_variant_key_samplers(key);
+      const struct lp_static_sampler_state *sampler = &samplers[i].sampler_state;
       debug_printf("sampler[%u] = \n", i);
       debug_printf("  .wrap = %s %s %s\n",
                    util_str_tex_wrap(sampler->wrap_s, TRUE),
@@ -664,7 +667,8 @@ dump_cs_variant_key(const struct lp_compute_shader_variant_key *key)
       debug_printf("  .aniso = %u\n", sampler->aniso);
    }
    for (i = 0; i < key->nr_sampler_views; ++i) {
-      const struct lp_static_texture_state *texture = &key->samplers[i].texture_state;
+      const struct lp_sampler_static_state *samplers = lp_cs_variant_key_samplers(key);
+      const struct lp_static_texture_state *texture = &samplers[i].texture_state;
       debug_printf("texture[%u] = \n", i);
       debug_printf("  .format = %s\n",
                    util_format_name(texture->format));

src/gallium/drivers/llvmpipe/lp_state_cs.h

@@ -42,8 +42,6 @@ struct lp_compute_shader_variant_key
    unsigned nr_samplers:8;
    unsigned nr_sampler_views:8;
    unsigned nr_images:8;
-   /* followed by variable number of images */
-   struct lp_sampler_static_state samplers[1];
 };
 
 #define LP_CS_MAX_VARIANT_KEY_SIZE                                      \
@@ -54,17 +52,22 @@ struct lp_compute_shader_variant_key
 static inline size_t
 lp_cs_variant_key_size(unsigned nr_samplers, unsigned nr_images)
 {
-   unsigned samplers = nr_samplers > 1 ? (nr_samplers - 1) : 0;
    return (sizeof(struct lp_compute_shader_variant_key) +
-           samplers * sizeof(struct lp_sampler_static_state) +
+           nr_samplers * sizeof(struct lp_sampler_static_state) +
            nr_images * sizeof(struct lp_image_static_state));
 }
 
+static inline struct lp_sampler_static_state *
+lp_cs_variant_key_samplers(const struct lp_compute_shader_variant_key *key)
+{
+   return (struct lp_sampler_static_state *)&(key[1]);
+}
+
 static inline struct lp_image_static_state *
 lp_cs_variant_key_images(const struct lp_compute_shader_variant_key *key)
 {
    return (struct lp_image_static_state *)
-      &key->samplers[key->nr_samplers];
+      &(lp_cs_variant_key_samplers(key)[key->nr_samplers]);
 }
 
 struct lp_cs_variant_list_item

src/gallium/drivers/llvmpipe/lp_state_fs.c

@@ -3158,7 +3158,7 @@ generate_fragment(struct llvmpipe_context *lp,
    }
 
    /* code generated texture sampling */
-   sampler = lp_llvm_sampler_soa_create(key->samplers, key->nr_samplers);
+   sampler = lp_llvm_sampler_soa_create(lp_fs_variant_key_samplers(key), key->nr_samplers);
    image = lp_llvm_image_soa_create(lp_fs_variant_key_images(key), key->nr_images);
 
    num_fs = 16 / fs_type.length; /* number of loops per 4x4 stamp */
@@ -3432,7 +3432,8 @@ dump_fs_variant_key(struct lp_fragment_shader_variant_key *key)
       debug_printf("blend.alpha_to_coverage is enabled\n");
    }
    for (i = 0; i < key->nr_samplers; ++i) {
-      const struct lp_static_sampler_state *sampler = &key->samplers[i].sampler_state;
+      const struct lp_sampler_static_state *samplers = lp_fs_variant_key_samplers(key);
+      const struct lp_static_sampler_state *sampler = &samplers[i].sampler_state;
       debug_printf("sampler[%u] = \n", i);
       debug_printf("  .wrap = %s %s %s\n",
                    util_str_tex_wrap(sampler->wrap_s, TRUE),
@@ -3455,7 +3456,8 @@ dump_fs_variant_key(struct lp_fragment_shader_variant_key *key)
       debug_printf("  .aniso = %u\n", sampler->aniso);
    }
    for (i = 0; i < key->nr_sampler_views; ++i) {
-      const struct lp_static_texture_state *texture = &key->samplers[i].texture_state;
+      const struct lp_sampler_static_state *samplers = lp_fs_variant_key_samplers(key);
+      const struct lp_static_texture_state *texture = &samplers[i].texture_state;
       debug_printf("texture[%u] = \n", i);
       debug_printf("  .format = %s\n",
                    util_format_name(texture->format));
@@ -3645,15 +3647,16 @@ generate_variant(struct llvmpipe_context *lp,
         shader->kind == LP_FS_KIND_BLIT_RGB1)) {
       unsigned target, min_img_filter, mag_img_filter, min_mip_filter;
       enum pipe_format texture_format;
-
+      struct lp_sampler_static_state *samp0 = lp_fs_variant_key_sampler_idx(key, 0);
-      texture_format = key->samplers[0].texture_state.format;
+      assert(samp0);
-      target = key->samplers[0].texture_state.target;
+      texture_format = samp0->texture_state.format;
-      min_img_filter = key->samplers[0].sampler_state.min_img_filter;
+      target = samp0->texture_state.target;
-      mag_img_filter = key->samplers[0].sampler_state.mag_img_filter;
+      min_img_filter = samp0->sampler_state.min_img_filter;
-      if (key->samplers[0].texture_state.level_zero_only) {
+      mag_img_filter = samp0->sampler_state.mag_img_filter;
+      if (samp0->texture_state.level_zero_only) {
          min_mip_filter = PIPE_TEX_MIPFILTER_NONE;
       } else {
-         min_mip_filter = key->samplers[0].sampler_state.min_mip_filter;
+         min_mip_filter = samp0->sampler_state.min_mip_filter;
       }
 
       if (target == PIPE_TEXTURE_2D &&
@@ -4138,7 +4141,7 @@ make_variant_key(struct llvmpipe_context *lp,
 
    key = (struct lp_fragment_shader_variant_key *)store;
 
-   memset(key, 0, offsetof(struct lp_fragment_shader_variant_key, samplers[1]));
+   memset(key, 0, sizeof(*key));
 
    if (lp->framebuffer.zsbuf) {
       enum pipe_format zsbuf_format = lp->framebuffer.zsbuf->format;
@@ -4283,7 +4286,7 @@ make_variant_key(struct llvmpipe_context *lp,
 
    struct lp_sampler_static_state *fs_sampler;
 
-   fs_sampler = key->samplers;
+   fs_sampler = lp_fs_variant_key_samplers(key);
 
    memset(fs_sampler, 0, MAX2(key->nr_samplers, key->nr_sampler_views) * sizeof *fs_sampler);
 
@@ -4334,8 +4337,10 @@ make_variant_key(struct llvmpipe_context *lp,
    }
 
    if (shader->kind == LP_FS_KIND_AERO_MINIFICATION) {
-      key->samplers[0].sampler_state.min_img_filter = PIPE_TEX_FILTER_NEAREST;
+      struct lp_sampler_static_state *samp0 = lp_fs_variant_key_sampler_idx(key, 0);
-      key->samplers[0].sampler_state.mag_img_filter = PIPE_TEX_FILTER_NEAREST;
+      assert(samp0);
+      samp0->sampler_state.min_img_filter = PIPE_TEX_FILTER_NEAREST;
+      samp0->sampler_state.mag_img_filter = PIPE_TEX_FILTER_NEAREST;
    }
 
    return key;

src/gallium/drivers/llvmpipe/lp_state_fs.h

@@ -111,9 +111,7 @@ struct lp_fragment_shader_variant_key
    uint8_t zsbuf_nr_samples;
    uint8_t coverage_samples;
    uint8_t min_samples;
-
+   /* followed by variable number of samplers + images */
-   struct lp_sampler_static_state samplers[1];
-   /* followed by variable number of images */
 };
 
 #define LP_FS_MAX_VARIANT_KEY_SIZE                                      \
@@ -124,17 +122,30 @@ struct lp_fragment_shader_variant_key
 static inline size_t
 lp_fs_variant_key_size(unsigned nr_samplers, unsigned nr_images)
 {
-   unsigned samplers = nr_samplers > 1 ? (nr_samplers - 1) : 0;
    return (sizeof(struct lp_fragment_shader_variant_key) +
-           samplers * sizeof(struct lp_sampler_static_state) +
+           nr_samplers * sizeof(struct lp_sampler_static_state) +
            nr_images * sizeof(struct lp_image_static_state));
 }
 
+static inline struct lp_sampler_static_state *
+lp_fs_variant_key_samplers(const struct lp_fragment_shader_variant_key *key)
+{
+   return (struct lp_sampler_static_state *)&(key[1]);
+}
+
+static inline struct lp_sampler_static_state *
+lp_fs_variant_key_sampler_idx(const struct lp_fragment_shader_variant_key *key, int idx)
+{
+   if (idx >= key->nr_samplers)
+      return NULL;
+   return &lp_fs_variant_key_samplers(key)[idx];
+}
+
 static inline struct lp_image_static_state *
 lp_fs_variant_key_images(struct lp_fragment_shader_variant_key *key)
 {
    return (struct lp_image_static_state *)
-      &key->samplers[key->nr_samplers];
+      &(lp_fs_variant_key_samplers(key)[key->nr_samplers]);
 }
 
 /** doubly-linked list item */

src/gallium/drivers/llvmpipe/lp_state_fs_linear.c

@@ -667,16 +667,20 @@ is_one_inv_src_alpha_blend(const struct lp_fragment_shader_variant *variant)
 void
 llvmpipe_fs_variant_linear_fastpath(struct lp_fragment_shader_variant *variant)
 {
-   enum pipe_format tex_format = variant->key.samplers[0].texture_state.format;
+   struct lp_sampler_static_state *samp0 = lp_fs_variant_key_sampler_idx(&variant->key, 0);
 
    if (LP_PERF & PERF_NO_SHADE) {
       variant->jit_linear                   = linear_red;
       return;
    }
 
+   if (!samp0)
+      return;
+
+   enum pipe_format tex_format = samp0->texture_state.format;
    if (variant->shader->kind == LP_FS_KIND_BLIT_RGBA &&
        tex_format == PIPE_FORMAT_B8G8R8A8_UNORM &&
-       is_nearest_clamp_sampler(&variant->key.samplers[0])) {
+       is_nearest_clamp_sampler(samp0)) {
       if (variant->opaque) {
          variant->jit_linear_blit             = blit_rgba_blit;
          variant->jit_linear                  = blit_rgba;
@@ -692,7 +696,7 @@ llvmpipe_fs_variant_linear_fastpath(struct lp_fragment_shader_variant *variant)
        variant->opaque &&
        (tex_format == PIPE_FORMAT_B8G8R8A8_UNORM ||
         tex_format == PIPE_FORMAT_B8G8R8X8_UNORM) &&
-       is_nearest_clamp_sampler(&variant->key.samplers[0])) {
+       is_nearest_clamp_sampler(samp0)) {
       variant->jit_linear_blit             = blit_rgb1_blit;
       variant->jit_linear                  = blit_rgb1;
       return;