glsl: During linking, record whether a GS uses EndPrimitive().

This information will be useful in the i965 back end, since we can
save some compilation effort if we know from the outset that the
shader never calls EndPrimitive().

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 65afc2e..8a143fd 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -249,6 +249,33 @@
 };
 
 
+/**
+ * Visitor that determines whether or not a shader uses ir_end_primitive.
+ */
+class find_end_primitive_visitor : public ir_hierarchical_visitor {
+public:
+   find_end_primitive_visitor()
+      : found(false)
+   {
+      /* empty */
+   }
+
+   virtual ir_visitor_status visit(ir_end_primitive *)
+   {
+      found = true;
+      return visit_stop;
+   }
+
+   bool end_primitive_found()
+   {
+      return found;
+   }
+
+private:
+   bool found;
+};
+
+
 void
 linker_error(gl_shader_program *prog, const char *fmt, ...)
 {
@@ -517,6 +544,10 @@
 
    analyze_clip_usage("geometry", prog, shader, &prog->Geom.UsesClipDistance,
                       &prog->Geom.ClipDistanceArraySize);
+
+   find_end_primitive_visitor end_primitive;
+   end_primitive.run(shader->ir);
+   prog->Geom.UsesEndPrimitive = end_primitive.end_primitive_found();
 }