mesa: Add GL and GLSL plumbing for ARB_post_depth_coverage for i965 (gen9+).

This extension allows the fragment shader to control whether values in
gl_SampleMaskIn[] reflect the coverage after application of the early
depth and stencil tests.

Signed-off-by: Plamena Manolova <[email protected]>
Reviewed-by: Chris Forbes <[email protected]>

7 files changed, 48 insertions, 1 deletions

diff --git a/src/compiler/glsl/ast.h b/src/compiler/glsl/ast.h
index afe91ea6d32..df3a744de9c 100644
--- a/src/compiler/glsl/ast.h
+++ b/src/compiler/glsl/ast.h
@@ -605,6 +605,11 @@ struct ast_type_qualifier {
          /** \{ */
          unsigned blend_support:1; /**< Are there any blend_support_ qualifiers */
          /** \} */
+
+         /**
+          * Flag set if GL_ARB_post_depth_coverage layout qualifier is used.
+          */
+         unsigned post_depth_coverage:1;
       }
       /** \brief Set of flags, accessed by name. */
       q;
diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index c2ce389713b..2434ce57505 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -3632,6 +3632,11 @@ apply_layout_qualifier_to_variable(const struct ast_type_qualifier *qual,
       _mesa_glsl_error(loc, state, "early_fragment_tests layout qualifier only "
                        "valid in fragment shader input layout declaration.");
    }
+
+   if (qual->flags.q.post_depth_coverage) {
+      _mesa_glsl_error(loc, state, "post_depth_coverage layout qualifier only "
+                       "valid in fragment shader input layout declaration.");
+   }
 }
 
 static void
diff --git a/src/compiler/glsl/ast_type.cpp b/src/compiler/glsl/ast_type.cpp
index 3431e242811..aa1ae7e4849 100644
--- a/src/compiler/glsl/ast_type.cpp
+++ b/src/compiler/glsl/ast_type.cpp
@@ -579,6 +579,7 @@ ast_type_qualifier::validate_in_qualifier(YYLTYPE *loc,
       break;
    case MESA_SHADER_FRAGMENT:
       valid_in_mask.flags.q.early_fragment_tests = 1;
+      valid_in_mask.flags.q.post_depth_coverage = 1;
       break;
    case MESA_SHADER_COMPUTE:
       valid_in_mask.flags.q.local_size = 7;
@@ -633,6 +634,11 @@ ast_type_qualifier::merge_into_in_qualifier(YYLTYPE *loc,
       state->in_qualifier->flags.q.early_fragment_tests = false;
    }
 
+   if (state->in_qualifier->flags.q.post_depth_coverage) {
+      state->fs_post_depth_coverage = true;
+      state->in_qualifier->flags.q.post_depth_coverage = false;
+   }
+
    /* We allow the creation of multiple cs_input_layout nodes. Coherence among
     * all existing nodes is checked later, when the AST node is transformed
     * into HIR.
@@ -761,7 +767,8 @@ ast_type_qualifier::validate_flags(YYLTYPE *loc,
                     bad.flags.q.point_mode ? " point_mode" : "",
                     bad.flags.q.vertices ? " vertices" : "",
                     bad.flags.q.subroutine ? " subroutine" : "",
-                    bad.flags.q.subroutine_def ? " subroutine_def" : "");
+                    bad.flags.q.subroutine_def ? " subroutine_def" : "",
+                    bad.flags.q.post_depth_coverage ? " post_depth_coverage" : "");
    return false;
 }
 
diff --git a/src/compiler/glsl/glsl_parser.yy b/src/compiler/glsl/glsl_parser.yy
index 0c3781c3361..09b7e79c40b 100644
--- a/src/compiler/glsl/glsl_parser.yy
+++ b/src/compiler/glsl/glsl_parser.yy
@@ -1392,6 +1392,24 @@ layout_qualifier_id:
 
             $$.flags.q.early_fragment_tests = 1;
          }
+
+         if (!$$.flags.i &&
+             match_layout_qualifier($1, "post_depth_coverage", state) == 0) {
+            if (state->stage != MESA_SHADER_FRAGMENT) {
+               _mesa_glsl_error(& @1, state,
+                                "post_depth_coverage layout qualifier only "
+                                "valid in fragment shaders");
+            }
+
+            if (state->ARB_post_depth_coverage_enable) {
+               $$.flags.q.post_depth_coverage = 1;
+            } else {
+               _mesa_glsl_error(& @1, state,
+                                "post_depth_coverage layout qualifier present, "
+                                "but the GL_ARB_post_depth_coverage extension "
+                                "is not enabled.");
+            }
+         }
       }
 
       /* Layout qualifiers for tessellation evaluation shaders. */
diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index 1e0298eb84e..d1fc98dd14e 100644
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -293,6 +293,7 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct gl_context *_ctx,
    this->in_qualifier = new(this) ast_type_qualifier();
    this->out_qualifier = new(this) ast_type_qualifier();
    this->fs_early_fragment_tests = false;
+   this->fs_post_depth_coverage = false;
    this->fs_blend_support = 0;
    memset(this->atomic_counter_offsets, 0,
           sizeof(this->atomic_counter_offsets));
@@ -606,6 +607,7 @@ static const _mesa_glsl_extension _mesa_glsl_supported_extensions[] = {
    EXT(ARB_fragment_layer_viewport),
    EXT(ARB_gpu_shader5),
    EXT(ARB_gpu_shader_fp64),
+   EXT(ARB_post_depth_coverage),
    EXT(ARB_sample_shading),
    EXT(ARB_separate_shader_objects),
    EXT(ARB_shader_atomic_counter_ops),
@@ -1690,6 +1692,7 @@ set_shader_inout_layout(struct gl_shader *shader,
       assert(!state->fs_pixel_center_integer);
       assert(!state->fs_origin_upper_left);
       assert(!state->fs_early_fragment_tests);
+      assert(!state->fs_post_depth_coverage);
    }
 
    for (unsigned i = 0; i < MAX_FEEDBACK_BUFFERS; i++) {
@@ -1810,6 +1813,7 @@ set_shader_inout_layout(struct gl_shader *shader,
       shader->info.ARB_fragment_coord_conventions_enable =
          state->ARB_fragment_coord_conventions_enable;
       shader->info.EarlyFragmentTests = state->fs_early_fragment_tests;
+      shader->info.PostDepthCoverage = state->fs_post_depth_coverage;
       shader->info.BlendSupport = state->fs_blend_support;
       break;
 
diff --git a/src/compiler/glsl/glsl_parser_extras.h b/src/compiler/glsl/glsl_parser_extras.h
index d757c1d76b2..4277d43aa72 100644
--- a/src/compiler/glsl/glsl_parser_extras.h
+++ b/src/compiler/glsl/glsl_parser_extras.h
@@ -610,6 +610,8 @@ struct _mesa_glsl_parse_state {
    bool ARB_gpu_shader5_warn;
    bool ARB_gpu_shader_fp64_enable;
    bool ARB_gpu_shader_fp64_warn;
+   bool ARB_post_depth_coverage_enable;
+   bool ARB_post_depth_coverage_warn;
    bool ARB_sample_shading_enable;
    bool ARB_sample_shading_warn;
    bool ARB_separate_shader_objects_enable;
@@ -786,6 +788,8 @@ struct _mesa_glsl_parse_state {
 
    bool fs_early_fragment_tests;
 
+   bool fs_post_depth_coverage;
+
    unsigned fs_blend_support;
 
    /**
diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
index 1aff5c7ffda..f650752fad4 100644
--- a/src/compiler/glsl/linker.cpp
+++ b/src/compiler/glsl/linker.cpp
@@ -1889,6 +1889,10 @@ link_fs_inout_layout_qualifiers(struct gl_shader_program *prog,
 
       linked_shader->info.EarlyFragmentTests |=
          shader->info.EarlyFragmentTests;
+
+      linked_shader->Program->info.fs.post_depth_coverage |=
+         shader->info.PostDepthCoverage;
+
       linked_shader->info.BlendSupport |= shader->info.BlendSupport;
    }
 }