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Re: Is CPP broken? (Re: Strange gcc error message)
H . J . Lu wrote:-
> In open_file (),
>
> /* Mark a regular, zero-length file never-reread now. */
> if (S_ISREG (file->st.st_mode) && file->st.st_size == 0)
> {
> _cpp_never_reread (file);
> close (file->fd);
> file->fd = -1;
> }
>
> return file;
I've taken an approach suggested by Zack in a private mail. We still
mark zero-length files not to be reread, but push a buffer of length
zero the first time. This means moving the above code fragment out of
open_file(), and doing the flagging in stack_include_file after
committing to pushing the file once.
The patch below bootstraps without regressions (I think - it's a bit
of a mess right now, particularly ObjC). I've checked that your example
issues no diagnostics and that the exit code is 0.
I also solved another issue that Zack pointed out: we would sometimes
issue a diagnostic twice (e.g. permission denied if the file were not
readable).
Unfortunately, I have no idea how to test for these things with
DejaGnu.
Neil.
* cppfiles.c (open_file): Don't mark zero-length files
never-reread here. Don't output diagnostics here either.
(stack_include_file): Mark them never-reread here.
(_cpp_read_file): Update.
Index: cppfiles.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cppfiles.c,v
retrieving revision 1.129
diff -u -p -r1.129 cppfiles.c
--- cppfiles.c 2001/08/22 20:37:17 1.129
+++ cppfiles.c 2001/10/08 06:52:59
@@ -248,30 +248,15 @@ open_file (pfile, filename)
if (file->fd != -1 && fstat (file->fd, &file->st) == 0)
{
+ if (!S_ISDIR (file->st.st_mode))
+ return file;
/* If it's a directory, we return null and continue the search
as the file we're looking for may appear elsewhere in the
search path. */
- if (S_ISDIR (file->st.st_mode))
- errno = ENOENT;
- else
- {
- /* Mark a regular, zero-length file never-reread now. */
- if (S_ISREG (file->st.st_mode) && file->st.st_size == 0)
- {
- _cpp_never_reread (file);
- close (file->fd);
- file->fd = -1;
- }
-
- return file;
- }
+ errno = ENOENT;
}
- /* Don't issue an error message if the file doesn't exist. */
file->err_no = errno;
- if (errno != ENOENT && errno != ENOTDIR)
- cpp_error_from_errno (pfile, file->name);
-
return 0;
}
@@ -302,9 +287,14 @@ stack_include_file (pfile, inc)
/* Not in cache? */
if (! inc->buffer)
{
- /* If an error occurs, do not try to read this file again. */
- if (read_include_file (pfile, inc))
+ /* Mark a regular, zero-length file never-reread. Zero-length
+ files are stacked the first time, so preprocessing a main
+ file of zero length does not raise an error. */
+ if (S_ISREG (inc->st.st_mode) && inc->st.st_size == 0)
+ _cpp_never_reread (inc);
+ else if (read_include_file (pfile, inc))
{
+ /* If an error occurs, do not try to read this file again. */
_cpp_never_reread (inc);
return false;
}
@@ -710,14 +700,14 @@ _cpp_read_file (pfile, fname)
const char *fname;
{
struct include_file *f = open_file (pfile, fname);
- bool stacked = false;
if (f == NULL)
- cpp_error_from_errno (pfile, fname);
- else
- stacked = stack_include_file (pfile, f);
+ {
+ cpp_error_from_errno (pfile, fname);
+ return false;
+ }
- return stacked;
+ return stack_include_file (pfile, f);
}
/* Do appropriate cleanup when a file buffer is popped off the input