gl-renderer: Add debug scope for shader generator

This helps accounting how many shaders live in the cache, what the
shader source code is, and when shaders are compiled.

Signed-off-by: Harish Krupo <harishkrupo@gmail.com>

v2: Resolved rebase conflicts.
    Put shader_scope in struct gl_renderer, remove struct
    gl_shader_generator.
    Wrote commit message.
    Rebased for "gl-renderer: rewrite fragment shaders" which completely
    changed how shader sources are generated.
    Added cache statistics to debug output on subscribe.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/renderer-gl/gl-renderer-internal.h

@@ -159,6 +159,7 @@ struct gl_renderer {
 	 * List constains cached shaders built from struct gl_shader_requirements
 	 */
 	struct wl_list shader_list;
+	struct weston_log_scope *shader_scope;
 };
 
 static inline struct gl_renderer *
@@ -202,4 +203,8 @@ int
 gl_shader_requirements_cmp(const struct gl_shader_requirements *a,
 			   const struct gl_shader_requirements *b);
 
+struct weston_log_scope *
+gl_shader_scope_create(struct weston_compositor *compositor,
+		       struct gl_renderer *gr);
+
 #endif /* GL_RENDERER_INTERNAL_H */

libweston/renderer-gl/gl-renderer.c

@@ -3340,6 +3340,7 @@ gl_renderer_destroy(struct weston_compositor *ec)
 	if (gr->fan_binding)
 		weston_binding_destroy(gr->fan_binding);
 
+	weston_log_scope_destroy(gr->shader_scope);
 	free(gr);
 }
 
@@ -3402,6 +3403,10 @@ gl_renderer_display_create(struct weston_compositor *ec,
 	wl_list_init(&gr->shader_list);
 	gr->platform = options->egl_platform;
 
+	gr->shader_scope = gl_shader_scope_create(ec, gr);
+	if (!gr->shader_scope)
+		goto fail;
+
 	if (gl_renderer_setup_egl_client_extensions(gr) < 0)
 		goto fail;
 
@@ -3490,6 +3495,7 @@ fail_with_error:
 fail_terminate:
 	eglTerminate(gr->egl_display);
 fail:
+	weston_log_scope_destroy(gr->shader_scope);
 	free(gr);
 	ec->renderer = NULL;
 	return -1;

libweston/renderer-gl/gl-shaders.c

@@ -34,6 +34,7 @@
 #include <assert.h>
 
 #include <libweston/libweston.h>
+#include <libweston/weston-log.h>
 #include <GLES2/gl2.h>
 
 #include <string.h>
@@ -113,7 +114,7 @@ gl_shader_destroy(struct gl_shader *shader)
 	free(shader);
 }
 
-static int
+static GLuint
 compile_shader(GLenum type, int count, const char **sources)
 {
 	GLuint s;
@@ -135,6 +136,20 @@ compile_shader(GLenum type, int count, const char **sources)
 	return s;
 }
 
+static char *
+create_shader_description_string(const struct gl_shader_requirements *req)
+{
+	int size;
+	char *str;
+
+	size = asprintf(&str, "%s %cgreen",
+			gl_shader_texture_variant_to_string(req->variant),
+			req->green_tint ? '+' : '-');
+	if (size < 0)
+		return NULL;
+	return str;
+}
+
 static char *
 create_shader_config_string(const struct gl_shader_requirements *req)
 {
@@ -155,6 +170,7 @@ struct gl_shader *
 gl_shader_create(struct gl_renderer *gr,
 		 const struct gl_shader_requirements *requirements)
 {
+	bool verbose = weston_log_scope_is_enabled(gr->shader_scope);
 	struct gl_shader *shader = NULL;
 	char msg[512];
 	GLint status;
@@ -170,6 +186,16 @@ gl_shader_create(struct gl_renderer *gr,
 	wl_list_init(&shader->link);
 	shader->key = *requirements;
 
+	if (verbose) {
+		char *desc;
+
+		desc = create_shader_description_string(requirements);
+		weston_log_scope_printf(gr->shader_scope,
+					"Compiling shader program for: %s\n",
+					desc);
+		free(desc);
+	}
+
 	sources[0] = vertex_shader;
 	shader->vertex_shader = compile_shader(GL_VERTEX_SHADER, 1, sources);
 	if (shader->vertex_shader == GL_NONE)
@@ -236,3 +262,45 @@ gl_shader_requirements_cmp(const struct gl_shader_requirements *a,
 {
 	return memcmp(a, b, sizeof(*a));
 }
+
+static void
+gl_shader_scope_new_subscription(struct weston_log_subscription *subs,
+				 void *data)
+{
+	static const char bar[] = "-----------------------------------------------------------------------------";
+	struct gl_renderer *gr = data;
+	struct gl_shader *shader;
+	int count = 0;
+	char *desc;
+
+	weston_log_subscription_printf(subs,
+				       "Vertex shader body:\n"
+				       "%s\n%s\n"
+				       "Fragment shader body:\n"
+				       "%s\n%s\n%s\n",
+				       bar, vertex_shader,
+				       bar, fragment_shader, bar);
+
+	weston_log_subscription_printf(subs, "Cached GLSL programs:\n");
+	wl_list_for_each(shader, &gr->shader_list, link) {
+		count++;
+		desc = create_shader_description_string(&shader->key);
+		weston_log_subscription_printf(subs,
+					       "%6u: %s\n",
+					       shader->program, desc);
+	}
+	weston_log_subscription_printf(subs, "Total: %d programs.\n", count);
+}
+
+struct weston_log_scope *
+gl_shader_scope_create(struct weston_compositor *compositor,
+		       struct gl_renderer *gr)
+{
+
+	return weston_compositor_add_log_scope(compositor,
+		"gl-shader-generator",
+		"GL renderer shader compilation and cache.\n",
+		gl_shader_scope_new_subscription,
+		NULL,
+		gr);
+}