PATCH for preprocessor/14103: [3.4/3.5 Regression] ICEs on "gcc -E-imacros foo.h baz.c"

[Per Bothner <per at bothner dot com>]

The attached patch fixes preprocessor/14103.
Tested on Fedora on mainline.
I haven't tested it on 3.4 but of course I'll
do that before checking it in.

I'll wait a day or two to give people a chance to
object before checking this into mainline and 3.4.

This isn't a minimal patch, because it fixes at
least one other problem:  The output from -E would
include a line with a bogus (very high) line number.
This was caused by LAST_SOURCE_LINE_LOCATION (in
pp_file_change) "wrapping around" in the case of
files included from the command line.  In that case
subtracting 2 was wrong, but just subtracting 1
is wrong in the normal case.  Hence the other changes.

My first patch failed for pch, so I needed a way to
test for pch, and that when I noticed that the pch
field in _cpp_file was misleadingly declared as a
4-value enum when it fact it is only set in one
place as a boolean.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/


2004-02-16  Per Bothner  <per@bothner.com>

	* cpphash.h (struct cpp_buffer):  Restore return_at_eof field.  This
	partly reverts my 2003-10-01 change, because we're back to logically
	including <command line> inside the main line.
	* cpplex.c (_cpp_get_fresh_line):  Check return_at_eof field.
	* cppmacro.c (cpp_scan_nooutput):  Set return_at_eof of current buffer.
	Fixes PR preprocessor/14103.

	* cppfiles.c (_cpp_stack_include):  When appropriate decrement
	line_table's highest_location, fixing LAST_SOURCE_LINE_LOCATION.
	(cpp_push_include):  Don't need to increment pfile's line field.
	* line-map.h (LAST_SOURCE_LINE_LOCATION):  Only decrement by 1.

	* c-ppoutput.c (print struct):  New first_time field.
	(init_pp_output):  Set print.first_time.
	(pp_file_change):  Use print.first_time, rather than MAIN_FILE_P,
	which is set also for (say) <command line>.  Clear print.first_time.

	* cppfiles.c (struct _cpp_file):  Comment and type for pch field
	does not match the code, so fix both.
	(should_stack_file):  Inline include_pch_p function.
	(include_pch_p):  Remove pointless function.

	* cpphash.h (struct cpp_buffer):  Remove unused search_cached field.

Index: c-ppoutput.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/c-ppoutput.c,v
retrieving revision 1.15
diff -u -p -r1.15 c-ppoutput.c
--- c-ppoutput.c	11 Feb 2004 15:29:23 -0000	1.15
+++ c-ppoutput.c	16 Feb 2004 19:29:08 -0000
@@ -36,6 +36,7 @@ static struct
   const cpp_token *source;	/* Source token for spacing.  */
   int src_line;			/* Line number currently being written.  */
   unsigned char printed;	/* Nonzero if something output at line.  */
+  bool first_time;		/* pp_file_change hasn't been called yet. */
 } print;
 
 /* General output routines.  */
@@ -118,6 +119,7 @@ init_pp_output (FILE *out_stream)
   print.printed = 0;
   print.prev = 0;
   print.outf = out_stream;
+  print.first_time = 1;
 }
 
 /* Writes out the preprocessed file, handling spacing and paste
@@ -365,12 +367,12 @@ pp_file_change (const struct line_map *m
 
   if (map != NULL)
     {
-      /* First time?  */
-      if (MAIN_FILE_P (map))
+      if (print.first_time)
 	{
 	  /* Avoid printing foo.i when the main file is foo.c.  */
 	  if (!cpp_get_options (parse_in)->preprocessed)
 	    print_line (map->start_location, flags);
+	  print.first_time = 0;
 	}
       else
 	{
Index: cppfiles.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cppfiles.c,v
retrieving revision 1.202
diff -u -p -r1.202 cppfiles.c
--- cppfiles.c	11 Feb 2004 15:29:23 -0000	1.202
+++ cppfiles.c	16 Feb 2004 19:29:08 -0000
@@ -109,11 +109,8 @@ struct _cpp_file
   /* If BUFFER above contains the true contents of the file.  */
   bool buffer_valid;
 
-  /* 0: file not known to be a PCH.
-     1: file is a PCH (on return from find_include_file).
-     2: file is not and never will be a valid precompiled header.
-     3: file is always a valid precompiled header.  */
-  uchar pch;
+  /* File is a PCH (on return from find_include_file). */
+  bool pch;
 };
 
 /* A singly-linked list for all searches for a given file name, with
@@ -180,7 +177,6 @@ static void read_name_map (cpp_dir *dir)
 static char *remap_filename (cpp_reader *pfile, _cpp_file *file);
 static char *append_file_to_dir (const char *fname, cpp_dir *dir);
 static bool validate_pch (cpp_reader *, _cpp_file *file, const char *pchname);
-static bool include_pch_p (_cpp_file *file);
 static int pchf_adder (void **slot, void *data);
 static int pchf_save_compare (const void *e1, const void *e2);
 static int pchf_compare (const void *d_p, const void *e_p);
@@ -577,7 +573,7 @@ should_stack_file (cpp_reader *pfile, _c
     return false;
 
   /* Handle PCH files immediately; don't stack them.  */
-  if (include_pch_p (file))
+  if (file->pch)
     {
       pfile->cb.read_pch (pfile, file->path, file->fd, file->pchname);
       close (file->fd);
@@ -747,13 +743,25 @@ _cpp_stack_include (cpp_reader *pfile, c
 		    enum include_type type)
 {
   struct cpp_dir *dir;
+  _cpp_file *file;
 
   dir = search_path_head (pfile, fname, angle_brackets, type);
   if (!dir)
     return false;
 
-  return _cpp_stack_file (pfile, _cpp_find_file (pfile, fname, dir, false),
-		     type == IT_IMPORT);
+  file = _cpp_find_file (pfile, fname, dir, false);
+
+  /* Compensate for the increment in linemap_add.  In the case of a
+     normal #include, we're currently at the start of the line
+     *following* the #include.  A separate source_location for this
+     location makes no sense (until we do the LC_LEAVE), and
+     complicates LAST_SOURCE_LINE_LOCATION.  This does not apply if we
+     found a PCH file (in which case linemap_add is not called) or we
+     were included from the command-line.  */
+  if (! file->pch && file->err_no == 0 && type != IT_CMDLINE)
+    pfile->line_table->highest_location--;
+
+  return _cpp_stack_file (pfile, file, type == IT_IMPORT);
 }
 
 /* Could not open FILE.  The complication is dependency output.  */
@@ -1032,8 +1040,6 @@ _cpp_compare_file_date (cpp_reader *pfil
 bool
 cpp_push_include (cpp_reader *pfile, const char *fname)
 {
-  /* Make the command line directive take up a line.  */
-  pfile->line++;
   return _cpp_stack_include (pfile, fname, false, IT_CMDLINE);
 }
 
@@ -1226,13 +1232,6 @@ remap_filename (cpp_reader *pfile, _cpp_
       dir = make_cpp_dir (pfile, new_dir, dir->sysp);
       fname = p + 1;
     }
-}
-
-/* Return true if FILE is usable by PCH.  */
-static bool
-include_pch_p (_cpp_file *file)
-{
-  return file->pch & 1;
 }
 
 /* Returns true if PCHNAME is a valid PCH file for FILE.  */
Index: cpphash.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cpphash.h,v
retrieving revision 1.210
diff -u -p -r1.210 cpphash.h
--- cpphash.h	12 Feb 2004 02:25:02 -0000	1.210
+++ cpphash.h	16 Feb 2004 19:29:08 -0000
@@ -310,9 +310,10 @@ struct cpp_buffer
      buffers.  */
   unsigned int from_stage3 : 1;
 
-  /* Nonzero means that the directory to start searching for ""
-     include files has been calculated and stored in "dir" below.  */
-  unsigned char search_cached;
+  /* At EOF, a buffer is automatically popped.  If RETURN_AT_EOF is
+     true, a CPP_EOF token is then returned.  Otherwise, the next
+     token from the enclosing buffer is returned.  */
+  unsigned int return_at_eof : 1;
 
   /* One for a system header, two for a C system header file that therefore
      needs to be extern "C" protected in C++, and zero otherwise. */
Index: cpplex.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cpplex.c,v
retrieving revision 1.251
diff -u -p -r1.251 cpplex.c
--- cpplex.c	11 Feb 2004 15:29:24 -0000	1.251
+++ cpplex.c	16 Feb 2004 19:29:09 -0000
@@ -747,6 +747,8 @@ _cpp_lex_token (cpp_reader *pfile)
 bool
 _cpp_get_fresh_line (cpp_reader *pfile)
 {
+  int return_at_eof;
+
   /* We can't get a new line until we leave the current directive.  */
   if (pfile->state.in_directive)
     return false;
@@ -779,9 +781,10 @@ _cpp_get_fresh_line (cpp_reader *pfile)
 			       CPP_BUF_COLUMN (buffer, buffer->cur),
 			       "no newline at end of file");
 	}
- 
+
+      return_at_eof = buffer->return_at_eof;
       _cpp_pop_buffer (pfile);
-      if (pfile->buffer == NULL)
+      if (pfile->buffer == NULL || return_at_eof)
 	return false;
     }
 }
Index: cppmacro.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cppmacro.c,v
retrieving revision 1.144
diff -u -p -r1.144 cppmacro.c
--- cppmacro.c	11 Feb 2004 15:29:28 -0000	1.144
+++ cppmacro.c	16 Feb 2004 19:29:09 -0000
@@ -1138,6 +1138,10 @@ cpp_sys_macro_p (cpp_reader *pfile)
 void
 cpp_scan_nooutput (cpp_reader *pfile)
 {
+  /* Request a CPP_EOF token at the end of this file, rather than
+     transparently continuing with the including file.  */
+  pfile->buffer->return_at_eof = true;
+
   if (CPP_OPTION (pfile, traditional))
     while (_cpp_read_logical_line_trad (pfile))
       ;
Index: line-map.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/line-map.h,v
retrieving revision 1.19
diff -u -p -r1.19 line-map.h
--- line-map.h	11 Feb 2004 15:29:30 -0000	1.19
+++ line-map.h	16 Feb 2004 19:29:09 -0000
@@ -147,7 +147,7 @@ extern void linemap_print_containing_fil
 #define LAST_SOURCE_LINE(MAP) \
   SOURCE_LINE (MAP, LAST_SOURCE_LINE_LOCATION (MAP))
 #define LAST_SOURCE_LINE_LOCATION(MAP) \
-  ((((MAP)[1].start_location - 2 - (MAP)->start_location) \
+  ((((MAP)[1].start_location - 1 - (MAP)->start_location) \
     & ~((1 << (MAP)->column_bits) - 1))			  \
    + (MAP)->start_location)