tgsi: handle parsing vertex streams

These are needed for ARB_gpu_shader5

Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>

src/gallium/auxiliary/tgsi/tgsi_build.c

@@ -233,7 +233,10 @@ tgsi_default_declaration_semantic( void )
 
    ds.Name = TGSI_SEMANTIC_POSITION;
    ds.Index = 0;
-   ds.Padding = 0;
+   ds.StreamX = 0;
+   ds.StreamY = 0;
+   ds.StreamZ = 0;
+   ds.StreamW = 0;
 
    return ds;
 }
@@ -242,6 +245,10 @@ static struct tgsi_declaration_semantic
 tgsi_build_declaration_semantic(
    unsigned semantic_name,
    unsigned semantic_index,
+   unsigned streamx,
+   unsigned streamy,
+   unsigned streamz,
+   unsigned streamw,
    struct tgsi_declaration *declaration,
    struct tgsi_header *header )
 {
@@ -252,7 +259,10 @@ tgsi_build_declaration_semantic(
 
    ds.Name = semantic_name;
    ds.Index = semantic_index;
-   ds.Padding = 0;
+   ds.StreamX = streamx;
+   ds.StreamY = streamy;
+   ds.StreamZ = streamz;
+   ds.StreamW = streamw;
 
    declaration_grow( declaration, header );
 
@@ -450,6 +460,10 @@ tgsi_build_full_declaration(
       *ds = tgsi_build_declaration_semantic(
          full_decl->Semantic.Name,
          full_decl->Semantic.Index,
+         full_decl->Semantic.StreamX,
+         full_decl->Semantic.StreamY,
+         full_decl->Semantic.StreamZ,
+         full_decl->Semantic.StreamW,
          declaration,
          header );
    }

src/gallium/auxiliary/tgsi/tgsi_text.c

@@ -1377,6 +1377,54 @@ static boolean parse_declaration( struct translate_ctx *ctx )
       }
    }
 
+   cur = ctx->cur;
+   eat_opt_white( &cur );
+   if (*cur == ',' &&
+       file == TGSI_FILE_OUTPUT && ctx->processor == PIPE_SHADER_GEOMETRY) {
+      cur++;
+      eat_opt_white(&cur);
+      if (str_match_nocase_whole(&cur, "STREAM")) {
+         uint stream[4];
+
+         eat_opt_white(&cur);
+         if (*cur != '(') {
+            report_error(ctx, "Expected '('");
+            return FALSE;
+         }
+         cur++;
+
+         for (int i = 0; i < 4; ++i) {
+            eat_opt_white(&cur);
+            if (!parse_uint(&cur, &stream[i])) {
+               report_error(ctx, "Expected literal integer");
+               return FALSE;
+            }
+
+            eat_opt_white(&cur);
+            if (i < 3) {
+               if (*cur != ',') {
+                  report_error(ctx, "Expected ','");
+                  return FALSE;
+               }
+               cur++;
+            }
+         }
+
+         if (*cur != ')') {
+            report_error(ctx, "Expected ')'");
+            return FALSE;
+         }
+         cur++;
+
+         decl.Semantic.StreamX = stream[0];
+         decl.Semantic.StreamY = stream[1];
+         decl.Semantic.StreamZ = stream[2];
+         decl.Semantic.StreamW = stream[3];
+
+         ctx->cur = cur;
+      }
+   }
+
    cur = ctx->cur;
    eat_opt_white( &cur );
    if (*cur == ',' && !is_vs_input) {

src/gallium/include/pipe/p_shader_tokens.h

@@ -192,7 +192,10 @@ struct tgsi_declaration_semantic
 {
    unsigned Name           : 8;  /**< one of TGSI_SEMANTIC_x */
    unsigned Index          : 16; /**< UINT */
-   unsigned Padding        : 8;
+   unsigned StreamX        : 2; /**< vertex stream (for GS output) */
+   unsigned StreamY        : 2;
+   unsigned StreamZ        : 2;
+   unsigned StreamW        : 2;
 };
 
 struct tgsi_declaration_resource {