emit precise keyword

TGSI has a different model for precise than GLSL, so we have to mark
all outputs that has gotten an precise operation output to it as
precise.

This only implements part of the 'precise' keyword (still lacking
support on individual operations), but it's enough to pass some dEQP
tests, in particular:

- dEQP-GLES31.functional.tessellation.common_edge.triangles_equal_spacing_precise
- dEQP-GLES31.functional.tessellation.common_edge.triangles_fractional_odd_spacing_precise
- dEQP-GLES31.functional.tessellation.common_edge.triangles_fractional_even_spacing_precise
- dEQP-GLES31.functional.tessellation.common_edge.quads_equal_spacing_precise
- dEQP-GLES31.functional.tessellation.common_edge.quads_fractional_odd_spacing_precise
- dEQP-GLES31.functional.tessellation.common_edge.quads_fractional_even_spacing_precise

v2: flipped ordering of "invariant" and "precise", to avoid compiler
errors if both are emitted.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_shader.c

@@ -66,6 +66,7 @@ struct vrend_shader_io {
    int first;
    unsigned                location;
    bool                    invariant;
+   bool                    precise;
    bool glsl_predefined_no_emit;
    bool glsl_no_index;
    bool glsl_gl_block;
@@ -808,6 +809,7 @@ iter_declaration(struct tgsi_iterate_context *iter,
       ctx->outputs[i].sid = decl->Semantic.Index;
       ctx->outputs[i].interpolate = decl->Interp.Interpolate;
       ctx->outputs[i].invariant = decl->Declaration.Invariant;
+      ctx->outputs[i].precise = false;
       ctx->outputs[i].first = decl->Range.First;
       ctx->outputs[i].glsl_predefined_no_emit = false;
       ctx->outputs[i].glsl_no_index = false;
@@ -2390,6 +2392,12 @@ get_destination_info(struct dump_ctx *ctx,
       if (dst_reg->Register.File == TGSI_FILE_OUTPUT) {
          for (uint32_t j = 0; j < ctx->num_outputs; j++) {
             if (ctx->outputs[j].first == dst_reg->Register.Index) {
+
+               if (inst->Instruction.Precise) {
+                  ctx->outputs[j].precise = true;
+                  ctx->shader_req_bits |= SHADER_REQ_GPU_SHADER5;
+               }
+
                if (ctx->glsl_ver_required >= 140 && ctx->outputs[j].name == TGSI_SEMANTIC_CLIPVERTEX) {
                   snprintf(dsts[i], 255, "clipv_tmp");
                } else if (ctx->outputs[j].name == TGSI_SEMANTIC_CLIPDIST) {
@@ -3871,12 +3879,21 @@ static char *emit_ios(struct dump_ctx *ctx, char *glsl_hdr)
                else
                   snprintf(buf, 255, "%sout vec4 %s[];\n", prefix, ctx->outputs[i].glsl_name);
             } else if (ctx->prog_type == TGSI_PROCESSOR_GEOMETRY && ctx->outputs[i].stream)
-               snprintf(buf, 255, "layout (stream = %d) %s%sout vec4 %s;\n", ctx->outputs[i].stream, prefix, ctx->outputs[i].invariant ? "invariant " : "", ctx->outputs[i].glsl_name);
+               snprintf(buf, 255, "layout (stream = %d) %s%s%sout vec4 %s;\n", ctx->outputs[i].stream, prefix,
+                        ctx->outputs[i].precise ? "precise " : "",
+                        ctx->outputs[i].invariant ? "invariant " : "",
+                        ctx->outputs[i].glsl_name);
             else
-               snprintf(buf, 255, "%s%sout vec4 %s;\n", prefix, ctx->outputs[i].invariant ? "invariant " : "", ctx->outputs[i].glsl_name);
+               snprintf(buf, 255, "%s%s%sout vec4 %s;\n", prefix,
+                        ctx->outputs[i].precise ? "precise " : "",
+                        ctx->outputs[i].invariant ? "invariant " : "",
+                        ctx->outputs[i].glsl_name);
             STRCAT_WITH_RET(glsl_hdr, buf);
-         } else if (ctx->outputs[i].invariant) {
+         } else if (ctx->outputs[i].invariant || ctx->outputs[i].precise) {
-            snprintf(buf, 255, "invariant %s;\n", ctx->outputs[i].glsl_name);
+            snprintf(buf, 255, "%s%s %s;\n",
+               ctx->outputs[i].precise ? "precise " : "",
+               ctx->outputs[i].invariant ? "invariant " : "",
+               ctx->outputs[i].glsl_name);
             STRCAT_WITH_RET(glsl_hdr, buf);
          }
       }