[preprocessor/91639] #includes at EOF

https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00280.html
	libcpp/
	PR preprocessor/91639
	* directives.c (do_include_common): Tell lexer we're a #include.
	* files.c (_cpp_stack_file): Lexer will have always incremented.
	* internal.h (struct cpp_context): Extend in_directive's
	semantics.
	* lex.c (_cpp_lex_direct): Increment line for final \n when lexing
	for an ISO #include.
	* line-map.c (linemap_line_start): Remember if we overflowed.

	gcc/testsuite/
	PR preprocessor/91639
	* c-c++-common/cpp/pr91639.c: New.
	* c-c++-common/cpp/pr91639-one.h: New.
	* c-c++-common/cpp/pr91639-two.h: New.

From-SVN: r275402

6 files changed, 39 insertions, 22 deletions

diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 6791b36..c418d75 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,14 @@
+2019-09-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR preprocessor/91639
+	* directives.c (do_include_common): Tell lexer we're a #include.
+	* files.c (_cpp_stack_file): Lexer will have always incremented.
+	* internal.h (struct cpp_context): Extend in_directive's
+	semantics.
+	* lex.c (_cpp_lex_direct): Increment line for final \n when lexing
+	for an ISO #include.
+	* line-map.c (linemap_line_start): Remember if we overflowed.
+
 2019-09-03  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* directives.c: Remove references to spu from comments.
diff --git a/libcpp/directives.c b/libcpp/directives.c
index 29d21ed..1c6b31e 100644
--- a/libcpp/directives.c
+++ b/libcpp/directives.c
@@ -818,6 +818,10 @@ do_include_common (cpp_reader *pfile, enum include_type type)
      callback can dump comments which follow #include.  */
   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 
+  /* Tell the lexer this is an include directive -- we want it to
+     increment the line number even if this is the last line of a file.  */
+  pfile->state.in_directive = 2;
+
   fname = parse_include (pfile, &angle_brackets, &buf, &location);
   if (!fname)
     goto done;
diff --git a/libcpp/files.c b/libcpp/files.c
index ee31aff..aa77dc7 100644
--- a/libcpp/files.c
+++ b/libcpp/files.c
@@ -938,25 +938,16 @@ _cpp_stack_file (cpp_reader *pfile, _cpp_file *file, include_type type,
   pfile->mi_valid = true;
   pfile->mi_cmacro = 0;
 
-  /* Compensate for the increment in linemap_add that occurs when in
-     do_file_change.   In the case of a normal #include, we're
-     currently at the start of the line *following* the #include.  A
-     separate location_t 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.  In the
-     case that the #include is the last line in the file,
-     highest_location still points to the current line, not the start
-     of the next line, so we do not decrement in this case.  See
-     plugin/location-overflow-test-pr83173.h for an example.  */
-  bool decremented = false;
-  if (file->pchname == NULL && file->err_no == 0 && type < IT_DIRECTIVE_HWM)
-    {
-      decremented = (pfile->line_table->highest_line
-		     == pfile->line_table->highest_location);
-      if (decremented)
-	pfile->line_table->highest_location--;
-    }
+  /* In the case of a normal #include, we're now at the start of the
+     line *following* the #include.  A separate location_t for this
+     location makes no sense, until we do the LC_LEAVE.
+
+     This does not apply if we found a PCH file, we're not a regular
+     include, or we ran out of locations.  */
+  if (file->pchname == NULL
+      && type < IT_DIRECTIVE_HWM
+      && pfile->line_table->highest_location != LINE_MAP_MAX_LOCATION - 1)
+    pfile->line_table->highest_location--;
 
   /* Add line map and do callbacks.  */
   _cpp_do_file_change (pfile, LC_ENTER, file->path, 1, sysp);
diff --git a/libcpp/internal.h b/libcpp/internal.h
index d4768ae..f9bcd37 100644
--- a/libcpp/internal.h
+++ b/libcpp/internal.h
@@ -234,7 +234,8 @@ struct cpp_context
 
 struct lexer_state
 {
-  /* Nonzero if first token on line is CPP_HASH.  */
+  /* 1 if we're handling a directive.  2 if it's an include-like
+     directive.  */
   unsigned char in_directive;
 
   /* Nonzero if in a directive that will handle padding tokens itself.
diff --git a/libcpp/lex.c b/libcpp/lex.c
index 16ded6e..52e5bce 100644
--- a/libcpp/lex.c
+++ b/libcpp/lex.c
@@ -2771,7 +2771,13 @@ _cpp_lex_direct (cpp_reader *pfile)
       goto skipped_white;
 
     case '\n':
-      if (buffer->cur < buffer->rlimit)
+      /* Increment the line, unless this is the last line ...  */
+      if (buffer->cur < buffer->rlimit
+	  /* ... or this is a #include, (where _cpp_stack_file needs to
+	     unwind by one line) ...  */
+	  || (pfile->state.in_directive > 1
+	      /* ... except traditional-cpp increments this elsewhere.  */
+	      && !CPP_OPTION (pfile, traditional)))
 	CPP_INCREMENT_LINE (pfile, 0);
       buffer->need_line = true;
       goto fresh_line;
diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index 572d7f4..d6924eb 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -764,7 +764,11 @@ linemap_line_start (line_maps *set, linenum_type to_line,
   /* Locations of ordinary tokens are always lower than locations of
      macro tokens.  */
   if (r >= LINE_MAP_MAX_LOCATION)
-    return 0;
+    {
+      /* Remember we overflowed.  */
+      set->highest_line = set->highest_location = LINE_MAP_MAX_LOCATION - 1;
+      return 0;
+    }
 
   set->highest_line = r;
   if (r > set->highest_location)