Minimize the changes in #5277

Instead of including `mruby/presym.h` everywhere, we provided the
fallback `mruby/presym.inc` under `include/mruby` directory, and specify
`-I<build-dir>/include` before `-I<top-dir>/include` in `presym.rake`.
So even when someone drops `-I<build-dir>/include` in compiler options,
it just compiles without failure.

4 files changed, 53 insertions, 23 deletions

diff --git a/include/mruby.h b/include/mruby.h
index aa6d2ab65..57f556e94 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -1298,31 +1298,33 @@ MRB_API void mrb_print_error(mrb_state *mrb);
 /* function for `raisef` formatting */
 MRB_API mrb_value mrb_vformat(mrb_state *mrb, const char *format, va_list ap);
 
+#include <mruby/presym.h>
+
 /* macros to get typical exception objects
    note:
    + those E_* macros requires mrb_state* variable named mrb.
    + exception objects obtained from those macros are local to mrb
 */
-#define E_RUNTIME_ERROR      mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "RuntimeError"))
-#define E_TYPE_ERROR         mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "TypeError"))
-#define E_ZERODIV_ERROR      mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "ZeroDivisionError"))
-#define E_ARGUMENT_ERROR     mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "ArgumentError"))
-#define E_INDEX_ERROR        mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "IndexError"))
-#define E_RANGE_ERROR        mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "RangeError"))
-#define E_NAME_ERROR         mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "NameError"))
-#define E_NOMETHOD_ERROR     mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "NoMethodError"))
-#define E_SCRIPT_ERROR       mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "ScriptError"))
-#define E_SYNTAX_ERROR       mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "SyntaxError"))
-#define E_LOCALJUMP_ERROR    mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "LocalJumpError"))
-#define E_REGEXP_ERROR       mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "RegexpError"))
-#define E_FROZEN_ERROR       mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "FrozenError"))
-
-#define E_NOTIMP_ERROR       mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "NotImplementedError"))
+#define E_RUNTIME_ERROR             mrb_exc_get_id(mrb, MRB_SYM(RuntimeError))
+#define E_TYPE_ERROR                mrb_exc_get_id(mrb, MRB_SYM(TypeError))
+#define E_ZERODIV_ERROR             mrb_exc_get_id(mrb, MRB_SYM(ZeroDivisionError))
+#define E_ARGUMENT_ERROR            mrb_exc_get_id(mrb, MRB_SYM(ArgumentError))
+#define E_INDEX_ERROR               mrb_exc_get_id(mrb, MRB_SYM(IndexError))
+#define E_RANGE_ERROR               mrb_exc_get_id(mrb, MRB_SYM(RangeError))
+#define E_NAME_ERROR                mrb_exc_get_id(mrb, MRB_SYM(NameError))
+#define E_NOMETHOD_ERROR            mrb_exc_get_id(mrb, MRB_SYM(NoMethodError))
+#define E_SCRIPT_ERROR              mrb_exc_get_id(mrb, MRB_SYM(ScriptError))
+#define E_SYNTAX_ERROR              mrb_exc_get_id(mrb, MRB_SYM(SyntaxError))
+#define E_LOCALJUMP_ERROR           mrb_exc_get_id(mrb, MRB_SYM(LocalJumpError))
+#define E_REGEXP_ERROR              mrb_exc_get_id(mrb, MRB_SYM(RegexpError))
+#define E_FROZEN_ERROR              mrb_exc_get_id(mrb, MRB_SYM(FrozenError))
+
+#define E_NOTIMP_ERROR              mrb_exc_get_id(mrb, MRB_SYM(NotImplementedError))
 #ifndef MRB_NO_FLOAT
-#define E_FLOATDOMAIN_ERROR  mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "FloatDomainError"))
+#define E_FLOATDOMAIN_ERROR         mrb_exc_get_id(mrb, MRB_SYM(FloatDomainError))
 #endif
 
-#define E_KEY_ERROR          mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "KeyError"))
+#define E_KEY_ERROR                 mrb_exc_get_id(mrb, MRB_SYM(KeyError))
 
 MRB_API mrb_value mrb_yield(mrb_state *mrb, mrb_value b, mrb_value arg);
 MRB_API mrb_value mrb_yield_argv(mrb_state *mrb, mrb_value b, mrb_int argc, const mrb_value *argv);
@@ -1389,7 +1391,7 @@ MRB_API mrb_value mrb_fiber_alive_p(mrb_state *mrb, mrb_value fib);
  *
  * Implemented in mruby-fiber
  */
-#define E_FIBER_ERROR mrb_exc_get_id(mrb, mrb_intern_lit(mrb, "FiberError"))
+#define E_FIBER_ERROR (mrb_exc_get_id(mrb, MRB_SYM(FiberError)))
 MRB_API void mrb_stack_extend(mrb_state*, mrb_int);
 
 /* memory pool implementation */
@@ -1409,10 +1411,6 @@ MRB_API void mrb_show_copyright(mrb_state *mrb);
 
 MRB_API mrb_value mrb_format(mrb_state *mrb, const char *format, ...);
 
-#ifdef MRB_PRESYM_SCANNING
-# include <mruby/presym/scanning.h>
-#endif
-
 #if 0
 /* memcpy and memset does not work with gdb reverse-next on my box */
 /* use naive memcpy and memset instead */
diff --git a/include/mruby/presym.h b/include/mruby/presym.h
index 066b675e7..e3ce9214c 100644
--- a/include/mruby/presym.h
+++ b/include/mruby/presym.h
@@ -9,7 +9,9 @@
 
 #if defined(MRB_NO_PRESYM)
 # include <mruby/presym/disable.h>
-#elif !defined(MRB_PRESYM_SCANNING)
+#elif defined(MRB_PRESYM_SCANNING)
+# include <mruby/presym/scanning.h>
+#else
 # include <mruby/presym/enable.h>
 #endif
 
diff --git a/include/mruby/presym.inc b/include/mruby/presym.inc
new file mode 100644
index 000000000..8eced3d4f
--- /dev/null
+++ b/include/mruby/presym.inc
@@ -0,0 +1,14 @@
+/**
+** @file mruby/presym.inc - Fallback file for Preallocated Symbols
+**
+** See Copyright Notice in mruby.h
+*/
+
+/*
+ * Reading this file means you failed to specify `-I<build-dir>/include`
+ * in the configuration. I will not use `PRESYM*` macros for compilation.
+ */
+
+# error "mruby/presym.h"
+1 1 + + d
+#define MRB_NO_PRESYM
diff --git a/include/mruby/presym/enable.h b/include/mruby/presym/enable.h
index ddeb17e32..4f03e6689 100644
--- a/include/mruby/presym/enable.h
+++ b/include/mruby/presym/enable.h
@@ -8,6 +8,20 @@
 #define MRUBY_PRESYM_ENABLE_H
 
 #undef MRB_PRESYM_MAX
+#define MRB_PRESYM_NAMED(lit, num, type, name)
+#define MRB_PRESYM_UNNAMED(lit, num)
+/* test for proper -I `<build-dir>/include` */
+/* fallback `presym.inc` defines `MRB_NO_PRESYM` */
+# include <mruby/presym.inc>
+
+#undef MRB_PRESYM_MAX
+#undef MRB_PRESYM_NAMED
+#undef MRB_PRESYM_UNNAMED
+
+#if defined(MRB_NO_PRESYM)
+# include <mruby/presym/disable.h>
+#else
+
 #define MRB_PRESYM_NAMED(lit, num, type, name) MRB_##type##__##name = (num),
 #define MRB_PRESYM_UNNAMED(lit, num)
 
@@ -38,4 +52,6 @@ enum mruby_presym {
   static const mrb_sym name[] = {__VA_ARGS__};                                \
   static void init_##name(mrb_state *mrb) {}
 
+#endif  /* !MRUBY_NO_PRESYM */
+
 #endif  /* MRUBY_PRESYM_ENABLE_H */