glsl: implement compiling/linking of separate compilation units

A shader program may consist of multiple shaders (source code units).
If we find there are unresolved functions after compiling the unit that
defines main(), we'll concatenate all the respective vertex or fragment
shaders then recompile.

This isn't foolproof but should work in most cases.

1 files changed, 115 insertions, 17 deletions

diff --git a/src/mesa/shader/slang/slang_link.c b/src/mesa/shader/slang/slang_link.c
index f98434892b6..e2daf72e7de 100644
--- a/src/mesa/shader/slang/slang_link.c
+++ b/src/mesa/shader/slang/slang_link.c
@@ -534,6 +534,106 @@ _slang_update_inputs_outputs(struct gl_program *prog)
 }
 
 
+
+
+
+/**
+ * Return a new shader whose source code is the concatenation of
+ * all the shader sources of the given type.
+ */
+static struct gl_shader *
+concat_shaders(struct gl_shader_program *shProg, GLenum shaderType)
+{
+   struct gl_shader *newShader;
+   const struct gl_shader *firstShader = NULL;
+   GLuint shaderLengths[100];
+   GLchar *source;
+   GLuint totalLen = 0, len = 0;
+   GLuint i;
+
+   /* compute total size of new shader source code */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      const struct gl_shader *shader = shProg->Shaders[i];
+      if (shader->Type == shaderType) {
+         shaderLengths[i] = _mesa_strlen(shader->Source);
+         totalLen += shaderLengths[i];
+         if (!firstShader)
+            firstShader = shader;
+      }
+   }
+
+   source = (GLchar *) _mesa_malloc(totalLen + 1);
+   if (!source)
+      return NULL;
+
+   /* concatenate shaders */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      const struct gl_shader *shader = shProg->Shaders[i];
+      if (shader->Type == shaderType) {
+         _mesa_memcpy(source + len, shader->Source, shaderLengths[i]);
+         len += shaderLengths[i];
+      }
+   }
+   source[len] = '\0';
+   /*
+   _mesa_printf("---NEW CONCATENATED SHADER---:\n%s\n------------\n", source);
+   */
+
+   newShader = CALLOC_STRUCT(gl_shader);
+   newShader->Type = shaderType;
+   newShader->Source = source;
+   newShader->Pragmas = firstShader->Pragmas;
+
+   return newShader;
+}
+
+
+/**
+ * Search the shader program's list of shaders to find the one that
+ * defines main().
+ * This will involve shader concatenation and recompilation if needed.
+ */
+static struct gl_shader *
+get_main_shader(GLcontext *ctx,
+                struct gl_shader_program *shProg, GLenum type)
+{
+   struct gl_shader *shader = NULL;
+   GLuint i;
+
+   /*
+    * Look for a shader that defines main() and has no unresolved references.
+    */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      shader = shProg->Shaders[i];
+      if (shader->Type == type &&
+          shader->Main &&
+          !shader->UnresolvedRefs) {
+         /* All set! */
+         return shader;
+      }
+   }
+
+   /*
+    * There must have been unresolved references during the original
+    * compilation.  Try concatenating all the shaders of the given type
+    * and recompile that.
+    */
+   shader = concat_shaders(shProg, type);
+
+   _slang_compile(ctx, shader);
+
+   /* Finally, check if recompiling failed */
+   if (!shader->CompileStatus ||
+       !shader->Main ||
+       shader->UnresolvedRefs) {
+      link_error(shProg, "Unresolved symbols");
+      return NULL;
+   }
+
+   return shader;
+}
+
+
 /**
  * Shader linker.  Currently:
  *
@@ -557,6 +657,9 @@ _slang_link(GLcontext *ctx,
 
    _mesa_clear_shader_program_data(ctx, shProg);
 
+   /* Initialize LinkStatus to "success".  Will be cleared if error. */
+   shProg->LinkStatus = GL_TRUE;
+
    /* check that all programs compiled successfully */
    for (i = 0; i < shProg->NumShaders; i++) {
       if (!shProg->Shaders[i]->CompileStatus) {
@@ -568,24 +671,19 @@ _slang_link(GLcontext *ctx,
    shProg->Uniforms = _mesa_new_uniform_list();
    shProg->Varying = _mesa_new_parameter_list();
 
-   /**
-    * Find attached vertex, fragment shaders defining main()
+   /*
+    * Find the vertex and fragment shaders which define main()
     */
-   vertProg = NULL;
-   fragProg = NULL;
-   for (i = 0; i < shProg->NumShaders; i++) {
-      struct gl_shader *shader = shProg->Shaders[i];
-      if (shader->Type == GL_VERTEX_SHADER) {
-         if (shader->Main)
-            vertProg = vertex_program(shader->Program);
-      }
-      else if (shader->Type == GL_FRAGMENT_SHADER) {
-         if (shader->Main)
-            fragProg = fragment_program(shader->Program);
-      }
-      else {
-         _mesa_problem(ctx, "unexpected shader target in slang_link()");
-      }
+   {
+      struct gl_shader *vertShader, *fragShader;
+      vertShader = get_main_shader(ctx, shProg, GL_VERTEX_SHADER);
+      fragShader = get_main_shader(ctx, shProg, GL_FRAGMENT_SHADER);
+      if (vertShader)
+         vertProg = vertex_program(vertShader->Program);
+      if (fragShader)
+         fragProg = fragment_program(fragShader->Program);
+      if (!shProg->LinkStatus)
+         return;
    }
 
 #if FEATURE_es2_glsl