cpplib.c (struct pragma_entry): New structure.

	* cpplib.c (struct pragma_entry): New structure.
	(pragma_dispatch): Pragma dispatcher.
	(top_pragmas, gcc_pragmas): New static variables.
	(do_pragma): Use pragma_dispatch.
	(do_pragma_gcc): New pragma handler.
	* cpp.texi: Update.

From-SVN: r34663

gcc/ChangeLog

+2000-06-23  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* cpplib.c (struct pragma_entry): New structure.
+	(pragma_dispatch): Pragma dispatcher.
+	(top_pragmas, gcc_pragmas): New static variables.
+	(do_pragma): Use pragma_dispatch.
+	(do_pragma_gcc): New pragma handler.
+	* cpp.texi: Update.
+
 2000-06-23  Jakub Jelinek  <jakub@redhat.com>
 
 	* calls.c (compute_argument_addresses): Force stack slots into

gcc/cpp.texi

@@ -613,13 +613,13 @@ command line.  If the same directory is named by both @samp{-I} and
 @samp{-isystem}, @samp{-I} wins; it is as if the @samp{-isystem} option
 had never been specified at all.
 
-@findex #pragma system_header
-There is also a directive, @samp{#pragma system_header}, which tells GCC
+@findex #pragma GCC system_header
+There is also a directive, @samp{#pragma GCC system_header}, which tells GCC
 to consider the rest of the current include file a system header, no
 matter where it was found.  Code that comes before the @samp{#pragma} in
 the file will not be affected.
 
-@samp{#pragma system_header} has no effect in the primary source file.
+@samp{#pragma GCC system_header} has no effect in the primary source file.
 
 @node Macros, Conditionals, Header Files, Top
 @section Macros
@@ -1503,24 +1503,28 @@ Recall that a comment counts as whitespace.
 @node Poisoning, Macro Pitfalls, Redefining, Macros
 @subsection Poisoning Macros
 @cindex poisoning macros
+@findex #pragma GCC poison
+@findex #pragma poison
 
 Sometimes, there is an identifier that you want to remove completely
 from your program, and make sure that it never creeps back in.  To
-enforce this, the @samp{#pragma poison} directive can be used.
-@samp{#pragma poison} is followed by a list of identifiers to poison,
+enforce this, the @samp{#pragma GCC poison} directive can be used.
+@samp{#pragma GCC poison} is followed by a list of identifiers to poison,
 and takes effect for the rest of the source.  You cannot @samp{#undef} a
 poisoned identifier or test to see if it's defined with @samp{#ifdef}.
 
 For example,
 
 @example
-#pragma poison printf sprintf fprintf
+#pragma GCC poison printf sprintf fprintf
 sprintf(some_string, "hello");
 @end example
 
 @noindent
 will produce an error.
 
+For backwards compatibility @samp{#pragma poison} is also recognized.
+
 @node Macro Pitfalls,, Poisoning, Macros
 @subsection Pitfalls and Subtleties of Macros
 @cindex problems with macros
@@ -2637,11 +2641,15 @@ rather than a line of output containing just a @samp{#}.  Supposedly
 some old C programs contain such lines.
 
 @findex #pragma
+@findex #pragma GCC
+
 The ANSI standard specifies that the effect of the @samp{#pragma}
-directive is implementation-defined.  In the GNU C preprocessor,
-@samp{#pragma} directives are not used, except for @samp{#pragma once}
-(@pxref{Once-Only}).  However, they are left in the preprocessor output,
-so they are available to the compilation pass.
+directive is implementation-defined.  The GNU C preprocessor recognizes
+some pragmas, and passes unrecognized ones through to the preprocessor
+output, so they are available to the compilation pass.  GNU C preprocessor
+pragmas are of the form @samp{#pragma GCC ...}. For backwards
+compatibility previously supported pragmas are also recognized without
+the @samp{GCC}, however that use is deprecated.
 
 @findex #ident
 The @samp{#ident} directive is supported for compatibility with certain

gcc/cpplib.c

@@ -789,11 +789,50 @@ do_ident (pfile)
 
 /* Sub-handlers for the pragmas needing treatment here.
    They return 1 if the token buffer is to be popped, 0 if not. */
+struct pragma_entry
+{
+  char const *name;
+  int (*handler) PARAMS ((cpp_reader *));
+};
+
+static int pragma_dispatch             
+    PARAMS ((cpp_reader *, const struct pragma_entry *, U_CHAR *, size_t));
 static int do_pragma_once		PARAMS ((cpp_reader *));
 static int do_pragma_implementation	PARAMS ((cpp_reader *));
 static int do_pragma_poison		PARAMS ((cpp_reader *));
 static int do_pragma_system_header	PARAMS ((cpp_reader *));
 static int do_pragma_default		PARAMS ((cpp_reader *));
+static int do_pragma_gcc                PARAMS ((cpp_reader *));
+
+static const struct pragma_entry top_pragmas[] =
+{
+  {"once", do_pragma_once},
+  {"implementation", do_pragma_implementation},
+  {"poison", do_pragma_poison},
+  {"system_header", do_pragma_system_header},
+  {"GCC", do_pragma_gcc},
+  {NULL, do_pragma_default}
+};
+
+static const struct pragma_entry gcc_pragmas[] =
+{
+  {"implementation", do_pragma_implementation},
+  {"poison", do_pragma_poison},
+  {"system_header", do_pragma_system_header},
+  {NULL, do_pragma_default}
+};
+
+static int pragma_dispatch (pfile, table, p, len)
+     cpp_reader *pfile;
+     const struct pragma_entry *table;
+     U_CHAR *p;
+     size_t len;
+{
+  for (; table->name; table++)
+    if (strlen (table->name) == len && !memcmp (p, table->name, len))
+      return (*table->handler) (pfile);
+  return (*table->handler) (pfile);
+}
 
 static int
 do_pragma (pfile)
@@ -803,6 +842,7 @@ do_pragma (pfile)
   U_CHAR *buf;
   int pop;
   enum cpp_ttype token;
+  size_t  len;
 
   here = CPP_WRITTEN (pfile);
   CPP_PUTS (pfile, "#pragma ", 8);
@@ -819,20 +859,10 @@ do_pragma (pfile)
     }
 
   buf = pfile->token_buffer + key;
+  len = CPP_WRITTEN (pfile) - key;
   CPP_PUTC (pfile, ' ');
 
-#define tokis(x) !strncmp((char *) buf, x, sizeof(x) - 1)
-  if (tokis ("once"))
-    pop = do_pragma_once (pfile);
-  else if (tokis ("implementation"))
-    pop = do_pragma_implementation (pfile);
-  else if (tokis ("poison"))
-    pop = do_pragma_poison (pfile);
-  else if (tokis ("system_header"))
-    pop = do_pragma_system_header (pfile);
-  else
-    pop = do_pragma_default (pfile);
-#undef tokis
+  pop = pragma_dispatch (pfile, top_pragmas, buf, len);
 
   if (_cpp_get_directive_token (pfile) != CPP_VSPACE)
     goto skip;
@@ -861,6 +891,27 @@ do_pragma_default (pfile)
 }
 
 static int
+do_pragma_gcc (pfile)
+     cpp_reader *pfile;
+{
+  long key;
+  enum cpp_ttype token;
+  U_CHAR *buf;
+  size_t  len;
+  
+  key = CPP_WRITTEN (pfile);
+  token = _cpp_get_directive_token (pfile);
+  if (token != CPP_NAME)
+    return token == CPP_VSPACE;
+
+  buf = pfile->token_buffer + key;
+  len = CPP_WRITTEN (pfile) - key;
+  CPP_PUTC (pfile, ' ');
+  
+  return pragma_dispatch (pfile, gcc_pragmas, buf, len);
+}
+
+static int
 do_pragma_once (pfile)
      cpp_reader *pfile;
 {