[virglrenderer-devel] [PATCH] Implement invariant atrib for TGSI to GLSL

[Joe M. Kniss]

The 'invariant' output data attrib was not properly implemented in
mesa's TGSI serialization, and was ignored in virglrender's conversion
from TGSI text to GLSL text.   This patch adds 'invariant' support
and sets a new virgl cap to enable it since older versions of
virglrenderer will fail if invariant appears in the TGSI stream.

Tested: chromeos on qemu + virglrenderer
Signed-off-by: Joe M. Kniss <djmk at google.com>
---
 src/gallium/auxiliary/tgsi/tgsi_strings.c |  2 ++
 src/gallium/auxiliary/tgsi/tgsi_strings.h |  2 ++
 src/gallium/auxiliary/tgsi/tgsi_text.c    | 18 ++++++++++++++----
 src/virgl_hw.h                            |  1 +
 src/vrend_renderer.c                      |  2 ++
 src/vrend_shader.c                        |  8 +++++++-
 6 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.c b/src/gallium/auxiliary/tgsi/tgsi_strings.c
index fc29a23..b1995c0 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_strings.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_strings.c
@@ -166,6 +166,8 @@ const char *tgsi_interpolate_locations[TGSI_INTERPOLATE_LOC_COUNT] =
    "SAMPLE",
 };
 
+const char *tgsi_invariant_name = "INVARIANT";
+
 const char *tgsi_primitive_names[PIPE_PRIM_MAX] =
 {
    "POINTS",
diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.h b/src/gallium/auxiliary/tgsi/tgsi_strings.h
index 71e7437..1ecfcbc 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_strings.h
+++ b/src/gallium/auxiliary/tgsi/tgsi_strings.h
@@ -52,6 +52,8 @@ extern const char *tgsi_interpolate_names[TGSI_INTERPOLATE_COUNT];
 
 extern const char *tgsi_interpolate_locations[TGSI_INTERPOLATE_LOC_COUNT];
 
+extern const char *tgsi_invariant_name;
+
 extern const char *tgsi_primitive_names[PIPE_PRIM_MAX];
 
 extern const char *tgsi_fs_coord_origin_names[2];
diff --git a/src/gallium/auxiliary/tgsi/tgsi_text.c b/src/gallium/auxiliary/tgsi/tgsi_text.c
index 9d73668..3378148 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_text.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_text.c
@@ -1393,10 +1393,6 @@ static boolean parse_declaration( struct translate_ctx *ctx )
             break;
          }
       }
-      if (i == TGSI_INTERPOLATE_COUNT) {
-         report_error( ctx, "Expected semantic or interpolate attribute" );
-         return FALSE;
-      }
    }
 
    cur = ctx->cur;
@@ -1416,6 +1412,20 @@ static boolean parse_declaration( struct translate_ctx *ctx )
       }
    }
 
+   cur = ctx->cur;
+   eat_opt_white( &cur );
+   if (*cur == ',' && !is_vs_input) {
+      cur++;
+      eat_opt_white( &cur );
+      if (str_match_nocase_whole( &cur, tgsi_invariant_name )) {
+         decl.Declaration.Invariant = 1;
+         ctx->cur = cur;
+      } else {
+         report_error( ctx, "Expected semantic, interpolate attribute, or invariant \"%.10s...\" ", cur );
+         return FALSE;
+      }
+   }
+
    advance = tgsi_build_full_declaration(
       &decl,
       ctx->tokens_cur,
diff --git a/src/virgl_hw.h b/src/virgl_hw.h
index 7cbbeee..b27b698 100644
--- a/src/virgl_hw.h
+++ b/src/virgl_hw.h
@@ -290,6 +290,7 @@ struct virgl_caps_v2 {
         int32_t max_texture_gather_offset;
         uint32_t texture_buffer_offset_alignment;
         uint32_t uniform_buffer_offset_alignment;
+        uint32_t tgsi_invariant;
 };
 
 union virgl_caps {
diff --git a/src/vrend_renderer.c b/src/vrend_renderer.c
index 8e8f6f8..7483803 100644
--- a/src/vrend_renderer.c
+++ b/src/vrend_renderer.c
@@ -6870,6 +6870,8 @@ void vrend_renderer_fill_caps(uint32_t set, uint32_t version,
 
    if (gl_ver >= 43)
       glGetIntegerv(GL_TEXTURE_BUFFER_OFFSET_ALIGNMENT, &caps->v2.texture_buffer_offset_alignment);
+
+   caps->v2.tgsi_invariant = 1;
 }
 
 GLint64 vrend_renderer_get_timestamp(void)
diff --git a/src/vrend_shader.c b/src/vrend_shader.c
index 3f5fb22..bab603e 100644
--- a/src/vrend_shader.c
+++ b/src/vrend_shader.c
@@ -37,6 +37,7 @@ extern int vrend_dump_shaders;
 /* start convert of tgsi to glsl */
 
 #define INTERP_PREFIX "               "
+#define INVARI_PREFIX "invariant"
 
 struct vrend_shader_io {
    unsigned                name;
@@ -46,6 +47,7 @@ struct vrend_shader_io {
    unsigned                interpolate;
    unsigned first;
    bool                 centroid;
+   bool                    invariant;
    bool glsl_predefined_no_emit;
    bool glsl_no_index;
    bool glsl_gl_in;
@@ -468,6 +470,7 @@ iter_declaration(struct tgsi_iterate_context *iter,
       ctx->outputs[i].name = decl->Semantic.Name;
       ctx->outputs[i].sid = decl->Semantic.Index;
       ctx->outputs[i].interpolate = decl->Interp.Interpolate;
+      ctx->outputs[i].invariant = decl->Declaration.Invariant;
       ctx->outputs[i].first = decl->Range.First;
       ctx->outputs[i].glsl_predefined_no_emit = false;
       ctx->outputs[i].glsl_no_index = false;
@@ -2501,7 +2504,10 @@ static char *emit_ios(struct dump_ctx *ctx, char *glsl_hdr)
             } else
                prefix = "";
             /* ugly leave spaces to patch interp in later */
-            snprintf(buf, 255, "%sout vec4 %s;\n", prefix, ctx->outputs[i].glsl_name);
+            snprintf(buf, 255, "%s%sout vec4 %s;\n", prefix, ctx->outputs[i].invariant ? "invariant " : "", ctx->outputs[i].glsl_name);
+            STRCAT_WITH_RET(glsl_hdr, buf);
+         } else if (ctx->outputs[i].invariant) {
+            snprintf(buf, 255, "invariant %s;\n", ctx->outputs[i].glsl_name);
             STRCAT_WITH_RET(glsl_hdr, buf);
          }
       }
-- 
2.17.0.484.g0c8726318c-goog