[PATCH] Macro body is trailing array

https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01037.html
	* include/cpplib.h (enum cpp_macro_kind): New.
	(struct cpp_macro): Make body trailing array.  Add kind field,
	delete traditional flag.
	* internal.h (_cpp_new_macro): Declare.
	(_cpp_reserve_room): New inline.
	(_cpp_commit_buf): Declare.
	(_cpp_create_trad_definition): Return new macro.
	* lex.c (_cpp_commit_buff): New.
	* macro.c (macro_real_token_count): Count backwards.
	(replace_args): Pointer equality not orderedness.
	(_cpp_save_parameter): Use _cpp_reserve_room.
	(alloc_expansion_token): Delete.
	(lex_expansion_token): Return macro pointer.  Use _cpp_reserve_room.
	(create_iso_definition): Allocate macro itself.  Adjust for
	different allocation ordering.
	(_cpp_new_macro): New.
	(_cpp_create_definition): Adjust for API changes.
	* traditional.c (push_replacement_text): Don't set traditional
	flag.
	(save_replacement_text): Likewise.
	(_cpp_create_trad_definition): Allocate macro itself, Adjust for
	different allocation ordering.

From-SVN: r263622

1 files changed, 22 insertions, 12 deletions

diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 2b3440d..a0d0c53 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -671,6 +671,12 @@ struct cpp_dir
   dev_t dev;
 };
 
+/* The kind of the cpp_macro.  */
+enum cpp_macro_kind {
+  cmk_macro,	/* An ISO macro (token expansion).  */
+  cmk_traditional,	/* A traditional macro (text expansion).  */
+};
+
 /* Each macro definition is recorded in a cpp_macro structure.
    Variadic macros cannot occur with traditional cpp.  */
 struct GTY(()) cpp_macro {
@@ -683,15 +689,6 @@ struct GTY(()) cpp_macro {
 			length ("%h.paramc")))
     params;
 
-  /* Replacement tokens (ISO) or replacement text (traditional).  See
-     comment at top of cpptrad.c for how traditional function-like
-     macros are encoded.  */
-  union cpp_macro_u
-  {
-    cpp_token * GTY ((tag ("0"), length ("%0.count"))) tokens;
-    const unsigned char * GTY ((tag ("1"))) text;
-  } GTY ((desc ("%1.traditional"))) exp;
-
   /* Definition line number.  */
   source_location line;
 
@@ -701,6 +698,9 @@ struct GTY(()) cpp_macro {
   /* Number of parameters.  */
   unsigned short paramc;
 
+  /* The kind of this macro (ISO, trad or assert) */
+  unsigned kind : 2;
+
   /* If a function-like macro.  */
   unsigned int fun_like : 1;
 
@@ -713,13 +713,23 @@ struct GTY(()) cpp_macro {
   /* Nonzero if it has been expanded or had its existence tested.  */
   unsigned int used     : 1;
 
-  /* Indicate which field of 'exp' is in use.  */
-  unsigned int traditional : 1;
-
   /* Indicate whether the tokens include extra CPP_PASTE tokens at the
      end to track invalid redefinitions with consecutive CPP_PASTE
      tokens.  */
   unsigned int extra_tokens : 1;
+
+  /* 1 bits spare (32-bit). 33 on 64-bit target.  */
+
+  union cpp_exp_u
+  {
+    /* Trailing array of replacement tokens (ISO), or assertion body value.  */
+    cpp_token GTY ((tag ("false"), length ("%1.count"))) tokens[1];
+
+    /* Pointer to replacement text (traditional).  See comment at top
+       of cpptrad.c for how traditional function-like macros are
+       encoded.  */
+    const unsigned char *GTY ((tag ("true"))) text;
+  } GTY ((desc ("%1.kind == cmk_traditional"))) exp;
 };
 
 /* The structure of a node in the hash table.  The hash table has