[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

gcc/c-family/ChangeLog

 2018-08-17  Nathan Sidwell  <nathan@acm.org>
 
+	* c-ada-spec.c (macro_length, dump_ada_macros): Constify.
+
 	* c-ada-spec.c: Don't #include "cpp-id-data.h"
 	* c-cppbuiltin.c: Likewise.
 

gcc/c-family/c-ada-spec.c

@@ -88,7 +88,7 @@ macro_length (const cpp_macro *macro, int *supported, int *buffer_len,
 
   for (j = 0; j < macro->count; j++)
     {
-      cpp_token *token = &macro->exp.tokens[j];
+      const cpp_token *token = &macro->exp.tokens[j];
 
       if (token->flags & PREV_WHITE)
 	(*buffer_len)++;
@@ -274,7 +274,7 @@ dump_ada_macros (pretty_printer *pp, const char* file)
 
 	  for (i = 0; supported && i < macro->count; i++)
 	    {
-	      cpp_token *token = &macro->exp.tokens[i];
+	      const cpp_token *token = &macro->exp.tokens[i];
 	      int is_one = 0;
 
 	      if (token->flags & PREV_WHITE)

libcpp/ChangeLog

 2018-08-17  Nathan Sidwell  <nathan@acm.org>
 
+	* 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.
+
 	* cpp-id-data.h (uchar, UC): Move to internal.h
 	(struct cpp_macro): Move to cpplib.h.
 	* internal.h (uchar, UC): From cpp-id-data.h.

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

libcpp/internal.h

@@ -633,6 +633,7 @@ inline void _cpp_maybe_notify_macro_use (cpp_reader *pfile, cpp_hashnode *node)
   if (!(node->flags & NODE_USED))
     _cpp_notify_macro_use (pfile, node);
 }
+extern cpp_macro *_cpp_new_macro (cpp_reader *, cpp_macro_kind, void *);
 extern void _cpp_free_definition (cpp_hashnode *);
 extern bool _cpp_create_definition (cpp_reader *, cpp_hashnode *);
 extern void _cpp_pop_context (cpp_reader *);
@@ -697,6 +698,14 @@ extern void _cpp_init_tokenrun (tokenrun *, unsigned int);
 extern cpp_hashnode *_cpp_lex_identifier (cpp_reader *, const char *);
 extern int _cpp_remaining_tokens_num_in_context (cpp_context *);
 extern void _cpp_init_lexer (void);
+static inline void *_cpp_reserve_room (cpp_reader *pfile, size_t have,
+				       size_t extra)
+{
+  if (BUFF_ROOM (pfile->a_buff) < (have + extra))
+    _cpp_extend_buff (pfile, &pfile->a_buff, extra);
+  return BUFF_FRONT (pfile->a_buff);
+}
+extern void *_cpp_commit_buff (cpp_reader *pfile, size_t size);
 
 /* In init.c.  */
 extern void _cpp_maybe_push_include_file (cpp_reader *);
@@ -733,7 +742,7 @@ extern bool _cpp_read_logical_line_trad (cpp_reader *);
 extern void _cpp_overlay_buffer (cpp_reader *pfile, const unsigned char *,
 				 size_t);
 extern void _cpp_remove_overlay (cpp_reader *);
-extern bool _cpp_create_trad_definition (cpp_reader *, cpp_macro *);
+extern cpp_macro *_cpp_create_trad_definition (cpp_reader *);
 extern bool _cpp_expansions_different_trad (const cpp_macro *,
 					    const cpp_macro *);
 extern unsigned char *_cpp_copy_replacement_text (const cpp_macro *,

libcpp/lex.c

@@ -3725,6 +3725,25 @@ _cpp_aligned_alloc (cpp_reader *pfile, size_t len)
   return result;
 }
 
+/* Commit or allocate storage from a buffer.  */
+
+void *
+_cpp_commit_buff (cpp_reader *pfile, size_t size)
+{
+  void *ptr = BUFF_FRONT (pfile->a_buff);
+
+  if (pfile->hash_table->alloc_subobject)
+    {
+      void *copy = pfile->hash_table->alloc_subobject (size);
+      memcpy (copy, ptr, size);
+      ptr = copy;
+    }
+  else
+    BUFF_FRONT (pfile->a_buff) += size;
+
+  return ptr;
+}
+
 /* Say which field of TOK is in use.  */
 
 enum cpp_token_fld_kind

libcpp/traditional.c

@@ -853,7 +853,6 @@ push_replacement_text (cpp_reader *pfile, cpp_hashnode *node)
       cpp_macro *macro = node->value.macro;
       macro->used = 1;
       text = macro->exp.text;
-      macro->traditional = 1;
       len = macro->count;
     }
 
@@ -1143,7 +1142,6 @@ save_replacement_text (cpp_reader *pfile, cpp_macro *macro,
       memcpy (exp, pfile->out.base, len);
       exp[len] = '\n';
       macro->exp.text = exp;
-      macro->traditional = 1;
       macro->count = len;
     }
   else
@@ -1159,7 +1157,6 @@ save_replacement_text (cpp_reader *pfile, cpp_macro *macro,
       exp = BUFF_FRONT (pfile->a_buff);
       block = (struct block *) (exp + macro->count);
       macro->exp.text = exp;
-      macro->traditional = 1;
 
       /* Write out the block information.  */
       block->text_len = len;
@@ -1179,13 +1176,15 @@ save_replacement_text (cpp_reader *pfile, cpp_macro *macro,
 
 /* Analyze and save the replacement text of a macro.  Returns true on
    success.  */
-bool
-_cpp_create_trad_definition (cpp_reader *pfile, cpp_macro *macro)
+cpp_macro *
+_cpp_create_trad_definition (cpp_reader *pfile)
 {
   const uchar *cur;
   uchar *limit;
   cpp_context *context = pfile->context;
   unsigned nparms = 0;
+  int fun_like = 0;
+  cpp_hashnode **params = NULL;
 
   /* The context has not been set up for command line defines, and CUR
      has not been updated for the macro name for in-file defines.  */
@@ -1197,21 +1196,23 @@ _cpp_create_trad_definition (cpp_reader *pfile, cpp_macro *macro)
   /* Is this a function-like macro?  */
   if (* CUR (context) == '(')
     {
-      bool ok = scan_parameters (pfile, &nparms);
-      macro->paramc = nparms;
+      fun_like = +1;
+      if (scan_parameters (pfile, &nparms))
+	params = (cpp_hashnode **)_cpp_commit_buff
+	  (pfile, sizeof (cpp_hashnode *) * nparms);
+      else
+	fun_like = -1;
+    }
 
-      /* Remember the params so we can clear NODE_MACRO_ARG flags.  */
-      macro->params = (cpp_hashnode **) BUFF_FRONT (pfile->a_buff);
+  cpp_macro *macro = NULL;
 
-      /* Setting macro to NULL indicates an error occurred, and
-	 prevents unnecessary work in _cpp_scan_out_logical_line.  */
-      if (!ok)
-	macro = NULL;
-      else
+  if (fun_like >= 0)
     {
-	  BUFF_FRONT (pfile->a_buff) = (uchar *) &macro->params[macro->paramc];
-	  macro->fun_like = 1;
-	}
+      macro = _cpp_new_macro (pfile, cmk_traditional,
+			      _cpp_aligned_alloc (pfile, sizeof (cpp_macro)));
+      macro->params = params;
+      macro->paramc = nparms;
+      macro->fun_like = fun_like != 0;
     }
 
   /* Skip leading whitespace in the replacement text.  */
@@ -1225,9 +1226,8 @@ _cpp_create_trad_definition (cpp_reader *pfile, cpp_macro *macro)
 
   _cpp_unsave_parameters (pfile, nparms);
 
-  if (!macro)
-    return false;
-
+  if (macro)
+    {
       /* Skip trailing white space.  */
       cur = pfile->out.base;
       limit = pfile->out.cur;
@@ -1235,8 +1235,9 @@ _cpp_create_trad_definition (cpp_reader *pfile, cpp_macro *macro)
 	limit--;
       pfile->out.cur = limit;
       save_replacement_text (pfile, macro, 0);
+    }
 
-  return true;
+  return macro;
 }
 
 /* Copy SRC of length LEN to DEST, but convert all contiguous