mesa: Use shared code for converting shader targets to short strings.

We were duplicating this code all over the place, and they all would need
updating for the next set of shader targets.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

src/glsl/glsl_parser_extras.cpp

@@ -302,6 +302,41 @@ _mesa_glsl_parse_state::process_version_directive(YYLTYPE *locp, int version,
    }
 }
 
+extern "C" {
+
+/**
+ * The most common use of _mesa_glsl_shader_target_name(), which is
+ * shared with C code in Mesa core to translate a GLenum to a short
+ * shader stage name in debug printouts.
+ *
+ * It recognizes the PROGRAM variants of the names so it can be used
+ * with a struct gl_program->Target, not just a struct
+ * gl_shader->Type.
+ */
+const char *
+_mesa_glsl_shader_target_name(GLenum type)
+{
+   switch (type) {
+   case GL_VERTEX_SHADER:
+   case GL_VERTEX_PROGRAM_ARB:
+      return "vertex";
+   case GL_FRAGMENT_SHADER:
+   case GL_FRAGMENT_PROGRAM_ARB:
+      return "fragment";
+   case GL_GEOMETRY_SHADER:
+      return "geometry";
+   default:
+      assert(!"Should not get here.");
+      return "unknown";
+   }
+}
+
+} /* extern "C" */
+
+/**
+ * Overloaded C++ variant usable within the compiler for translating
+ * our internal enum into short stage names.
+ */
 const char *
 _mesa_glsl_shader_target_name(enum _mesa_glsl_parser_targets target)
 {