glsl: Slightly change the semantic of _LinkedShaders

Previously _LinkedShaders was a compact array of the linked shaders
for each shader stage.  Now it is arranged such that each slot,
indexed by the MESA_SHADER_* defines, refers to a specific shader
stage.  As a result, some slots will be NULL.  This makes things a
little more complex in the linker, but it simplifies things in other
places.

As a side effect _NumLinkedShaders is removed.

NOTE: This may be a candidate for the 7.9 branch.  If there are other
patches that get backported to 7.9 that use _LinkedShader, this patch
should be cherry picked also.

3 files changed, 20 insertions, 19 deletions

diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 10166ae5a2b..1625e4c5019 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -1702,10 +1702,10 @@ _mesa_valid_to_render(struct gl_context *ctx, const char *where)
       _mesa_update_state(ctx);
 
    if (ctx->Shader.CurrentProgram) {
-      unsigned i;
+      struct gl_shader_program *const prog = ctx->Shader.CurrentProgram;
 
       /* using shaders */
-      if (!ctx->Shader.CurrentProgram->LinkStatus) {
+      if (!prog->LinkStatus) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "%s(shader not linked)", where);
          return GL_FALSE;
@@ -1713,10 +1713,9 @@ _mesa_valid_to_render(struct gl_context *ctx, const char *where)
 #if 0 /* not normally enabled */
       {
          char errMsg[100];
-         if (!_mesa_validate_shader_program(ctx, ctx->Shader.CurrentProgram,
-                                            errMsg)) {
+         if (!_mesa_validate_shader_program(ctx, prog, errMsg)) {
             _mesa_warning(ctx, "Shader program %u is invalid: %s",
-                          ctx->Shader.CurrentProgram->Name, errMsg);
+                          prog->Name, errMsg);
          }
       }
 #endif
@@ -1725,13 +1724,12 @@ _mesa_valid_to_render(struct gl_context *ctx, const char *where)
        * any stages that are not provided, the corresponding assembly shader
        * target will be validated below.
        */
-      for (i = 0; i < ctx->Shader.CurrentProgram->_NumLinkedShaders; i++) {
-	 switch (ctx->Shader.CurrentProgram->_LinkedShaders[i]->Type) {
-	 case GL_VERTEX_SHADER: vert_from_glsl_shader = true; break;
-	 case GL_GEOMETRY_SHADER_ARB: geom_from_glsl_shader = true; break;
-	 case GL_FRAGMENT_SHADER: frag_from_glsl_shader = true; break;
-	 }
-      }
+      vert_from_glsl_shader =
+	 prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL;
+      geom_from_glsl_shader =
+	 prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL;
+      frag_from_glsl_shader =
+	 prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL;
    }
 
 
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 6702032679b..13aa66fc1e8 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2117,11 +2117,12 @@ struct gl_shader_program
 
    /**
     * Per-stage shaders resulting from the first stage of linking.
+    *
+    * Set of linked shaders for this program.  The array is accessed using the
+    * \c MESA_SHADER_* defines.  Entries for non-existent stages will be
+    * \c NULL.
     */
-   /*@{*/
-   GLuint _NumLinkedShaders;
-   struct gl_shader *_LinkedShaders[2];
-   /*@}*/
+   struct gl_shader *_LinkedShaders[MESA_SHADER_TYPES];
 };   
 
 
diff --git a/src/mesa/main/shaderobj.c b/src/mesa/main/shaderobj.c
index e0ffa2f289d..b6594cbe6f0 100644
--- a/src/mesa/main/shaderobj.c
+++ b/src/mesa/main/shaderobj.c
@@ -326,10 +326,12 @@ _mesa_free_shader_program_data(struct gl_context *ctx,
    shProg->TransformFeedback.NumVarying = 0;
 
 
-   for (i = 0; i < shProg->_NumLinkedShaders; i++) {
-      ctx->Driver.DeleteShader(ctx, shProg->_LinkedShaders[i]);
+   for (i = 0; i < MESA_SHADER_TYPES; i++) {
+      if (shProg->_LinkedShaders[i] != NULL) {
+	 ctx->Driver.DeleteShader(ctx, shProg->_LinkedShaders[i]);
+	 shProg->_LinkedShaders[i] = NULL;
+      }
    }
-   shProg->_NumLinkedShaders = 0;
 }