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Re: RFC: cache the CRC in the BFD
- From: Tom Tromey <tromey at redhat dot com>
- To: Sergio Durigan Junior <sergiodj at redhat dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 29 Jan 2013 12:00:46 -0700
- Subject: Re: RFC: cache the CRC in the BFD
- References: <87k3r1ez2z.fsf@fleche.redhat.com> <m3k3qznkws.fsf@redhat.com>
Sergio> The `parent_crc_p' variable is only used to check the return value of
Sergio> `gdb_bfd_crc', so IMO it could be removed, WDYT?
Sounds good.
Here's a new patch.
Tom
* gdb_bfd.c (struct gdb_bfd_data) <crc_computed, crc>:
New fields.
(get_file_crc): Move from symfile.c.
(gdb_bfd_crc): New function.
* gdb_bfd.h (gdb_bfd_crc): Declare.
* objfiles.h (struct objfile) <crc32, crc32_p>: Remove.
* symfile.c (get_file_crc): Move to gdb_bfd.c.
(separate_debug_file_exists): Use gdb_bfd_crc.
diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index ae561d3..f8d985d 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -81,6 +81,12 @@ struct gdb_bfd_data
/* The mtime of the BFD at the point the cache entry was made. */
time_t mtime;
+ /* This is true if we have successfully computed the file's CRC. */
+ unsigned int crc_computed : 1;
+
+ /* The file's CRC. */
+ unsigned long crc;
+
/* If the BFD comes from an archive, this points to the archive's
BFD. Otherwise, this is NULL. */
bfd *archive_bfd;
@@ -414,6 +420,58 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type *size)
return descriptor->data;
}
+/* Return 32-bit CRC for ABFD. If successful store it to *FILE_CRC_RETURN and
+ return 1. Otherwise print a warning and return 0. ABFD seek position is
+ not preserved. */
+
+static int
+get_file_crc (bfd *abfd, unsigned long *file_crc_return)
+{
+ unsigned long file_crc = 0;
+
+ if (bfd_seek (abfd, 0, SEEK_SET) != 0)
+ {
+ warning (_("Problem reading \"%s\" for CRC: %s"),
+ bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
+ return 0;
+ }
+
+ for (;;)
+ {
+ gdb_byte buffer[8 * 1024];
+ bfd_size_type count;
+
+ count = bfd_bread (buffer, sizeof (buffer), abfd);
+ if (count == (bfd_size_type) -1)
+ {
+ warning (_("Problem reading \"%s\" for CRC: %s"),
+ bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
+ return 0;
+ }
+ if (count == 0)
+ break;
+ file_crc = bfd_calc_gnu_debuglink_crc32 (file_crc, buffer, count);
+ }
+
+ *file_crc_return = file_crc;
+ return 1;
+}
+
+/* See gdb_bfd.h. */
+
+int
+gdb_bfd_crc (struct bfd *abfd, unsigned long *crc_out)
+{
+ struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
+
+ if (!gdata->crc_computed)
+ gdata->crc_computed = get_file_crc (abfd, &gdata->crc);
+
+ if (gdata->crc_computed)
+ *crc_out = gdata->crc;
+ return gdata->crc_computed;
+}
+
/* See gdb_bfd.h. */
diff --git a/gdb/gdb_bfd.h b/gdb/gdb_bfd.h
index f3ee9ff..1e74bfe 100644
--- a/gdb/gdb_bfd.h
+++ b/gdb/gdb_bfd.h
@@ -70,6 +70,12 @@ void gdb_bfd_mark_parent (bfd *child, bfd *parent);
const gdb_byte *gdb_bfd_map_section (asection *section, bfd_size_type *size);
+/* Compute the CRC for ABFD. The CRC is used to find and verify
+ separate debug files. When successful, this fills in *CRC_OUT and
+ returns 1. Otherwise, this issues a warning and returns 0. */
+
+int gdb_bfd_crc (struct bfd *abfd, unsigned long *crc_out);
+
/* A wrapper for bfd_fopen that initializes the gdb-specific reference
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index 6d29084..54ac646 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -259,11 +259,6 @@ struct objfile
long mtime;
- /* Cached 32-bit CRC as computed by gnu_debuglink_crc32. CRC32 is valid
- iff CRC32_P. */
- unsigned long crc32;
- int crc32_p;
-
/* Obstack to hold objects that should be freed when we load a new symbol
table from this object file. */
diff --git a/gdb/symfile.c b/gdb/symfile.c
index 4d65889..386c404 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -1348,43 +1348,6 @@ symbol_file_clear (int from_tty)
printf_unfiltered (_("No symbol file now.\n"));
}
-/* Return 32-bit CRC for ABFD. If successful store it to *FILE_CRC_RETURN and
- return 1. Otherwise print a warning and return 0. ABFD seek position is
- not preserved. */
-
-static int
-get_file_crc (bfd *abfd, unsigned long *file_crc_return)
-{
- unsigned long file_crc = 0;
-
- if (bfd_seek (abfd, 0, SEEK_SET) != 0)
- {
- warning (_("Problem reading \"%s\" for CRC: %s"),
- bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
- return 0;
- }
-
- for (;;)
- {
- gdb_byte buffer[8 * 1024];
- bfd_size_type count;
-
- count = bfd_bread (buffer, sizeof (buffer), abfd);
- if (count == (bfd_size_type) -1)
- {
- warning (_("Problem reading \"%s\" for CRC: %s"),
- bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
- return 0;
- }
- if (count == 0)
- break;
- file_crc = bfd_calc_gnu_debuglink_crc32 (file_crc, buffer, count);
- }
-
- *file_crc_return = file_crc;
- return 1;
-}
-
static int
separate_debug_file_exists (const char *name, unsigned long crc,
struct objfile *parent_objfile)
@@ -1434,7 +1397,7 @@ separate_debug_file_exists (const char *name, unsigned long crc,
else
verified_as_different = 0;
- file_crc_p = get_file_crc (abfd, &file_crc);
+ file_crc_p = gdb_bfd_crc (abfd, &file_crc);
gdb_bfd_unref (abfd);
@@ -1443,19 +1406,19 @@ separate_debug_file_exists (const char *name, unsigned long crc,
if (crc != file_crc)
{
+ unsigned long parent_crc;
+
/* If one (or both) the files are accessed for example the via "remote:"
gdbserver way it does not support the bfd_stat operation. Verify
whether those two files are not the same manually. */
- if (!verified_as_different && !parent_objfile->crc32_p)
+ if (!verified_as_different)
{
- parent_objfile->crc32_p = get_file_crc (parent_objfile->obfd,
- &parent_objfile->crc32);
- if (!parent_objfile->crc32_p)
+ if (!gdb_bfd_crc (parent_objfile->obfd, &parent_crc))
return 0;
}
- if (verified_as_different || parent_objfile->crc32 != file_crc)
+ if (verified_as_different || parent_crc != file_crc)
warning (_("the debug information found in \"%s\""
" does not match \"%s\" (CRC mismatch).\n"),
name, parent_objfile->name);