gallium: add PIPE_SHADER_CAP_SUBROUTINES

This fixes piglit/glsl-vs-main-return and glsl-fs-main-return for the drivers
which don't support RET (i915g, r300g, r600g, svga).

ir_to_mesa does not currently generate subroutines, but it's a matter of time
till it's added. It would then break all the drivers which don't implement
them, so this CAP makes sense.
Signed-off-by: Marek Olšák <maraeo@gmail.com>

src/gallium/auxiliary/tgsi/tgsi_exec.h

@@ -388,6 +388,8 @@ tgsi_exec_get_shader_param(enum pipe_shader_cap param)
    case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
    case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
       return 1;
+   case PIPE_SHADER_CAP_SUBROUTINES:
+      return 1;
    default:
       return 0;
    }

src/gallium/drivers/i915/i915_screen.c

@@ -189,6 +189,8 @@ i915_get_shader_param(struct pipe_screen *screen, unsigned shader, enum pipe_sha
       case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
          return 1;
+      case PIPE_SHADER_CAP_SUBROUTINES:
+         return 0;
       default:
          assert(0);
          return 0;

src/gallium/drivers/i965/brw_screen.c

@@ -240,6 +240,8 @@ brw_get_shader_param(struct pipe_screen *screen, unsigned shader, enum pipe_shad
       case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
           return 1;
+      case PIPE_SHADER_CAP_SUBROUTINES:
+          return 1;
       default:
          assert(0);
          return 0;

src/gallium/drivers/nv50/nv50_screen.c

@@ -176,6 +176,8 @@ nv50_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
 	case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
 	case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 		return 1;
+	case PIPE_SHADER_CAP_SUBROUTINES:
+		return 0;
 	default:
 		return 0;
 	}

src/gallium/drivers/nvfx/nvfx_screen.c

@@ -123,6 +123,8 @@ nvfx_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader, enum
 		case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
 		case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 			return 0;
+		case PIPE_SHADER_CAP_SUBROUTINES:
+			return screen->use_nv4x ? 1 : 0;
 		default:
 			break;
 		}
@@ -161,6 +163,8 @@ nvfx_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader, enum
 			return 0;
 		case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 			return 1;
+		case PIPE_SHADER_CAP_SUBROUTINES:
+			return 1;
 		default:
 			break;
 		}

src/gallium/drivers/r300/r300_screen.c

@@ -214,6 +214,8 @@ static int r300_get_shader_param(struct pipe_screen *pscreen, unsigned shader, e
         case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
         case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
             return 0;
+        case PIPE_SHADER_CAP_SUBROUTINES:
+            return 0;
         }
         break;
     case PIPE_SHADER_VERTEX:
@@ -251,6 +253,8 @@ static int r300_get_shader_param(struct pipe_screen *pscreen, unsigned shader, e
             return 0;
         case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
             return 1;
+        case PIPE_SHADER_CAP_SUBROUTINES:
+            return 0;
         default:
             break;
         }

src/gallium/drivers/r600/r600_pipe.c

@@ -375,6 +375,8 @@ static int r600_get_shader_param(struct pipe_screen* pscreen, unsigned shader, e
 	case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
 	case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 		return 1;
+	case PIPE_SHADER_CAP_SUBROUTINES:
+		return 0;
 	default:
 		return 0;
 	}

src/gallium/drivers/svga/svga_screen.c

@@ -237,6 +237,8 @@ static int svga_get_shader_param(struct pipe_screen *screen, unsigned shader, en
       case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
          return 0;
+      case PIPE_SHADER_CAP_SUBROUTINES:
+         return 0;
       }
       break;
    case PIPE_SHADER_VERTEX:
@@ -276,6 +278,8 @@ static int svga_get_shader_param(struct pipe_screen *screen, unsigned shader, en
          return 0;
       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
          return 1;
+      case PIPE_SHADER_CAP_SUBROUTINES:
+         return 0;
       default:
          break;
       }

src/gallium/include/pipe/p_defines.h

@@ -489,6 +489,7 @@ enum pipe_shader_cap
    PIPE_SHADER_CAP_INDIRECT_OUTPUT_ADDR,
    PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR,
    PIPE_SHADER_CAP_INDIRECT_CONST_ADDR,
+   PIPE_SHADER_CAP_SUBROUTINES, /* BGNSUB, ENDSUB, CAL, RET */
 };
 
 /**

src/mesa/state_tracker/st_extensions.c

@@ -169,9 +169,9 @@ void st_init_limits(struct st_context *st)
 
       /* TODO: make these more fine-grained if anyone needs it */
       options->EmitNoIfs = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH);
-      options->EmitNoFunctions = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH);
       options->EmitNoLoops = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH);
-      options->EmitNoMainReturn = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH);
+      options->EmitNoFunctions = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_SUBROUTINES);
+      options->EmitNoMainReturn = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_SUBROUTINES);
 
       options->EmitNoCont = !screen->get_shader_param(screen, i, PIPE_SHADER_CAP_TGSI_CONT_SUPPORTED);