| Message ID | 20181105211951.14945-1-keiths@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 11/05/2018 09:19 PM, Keith Seitz wrote: > This patch attempts to fix a bug dealing with setting breakpoints > in default symtabs that are symlinks. For example: > > (gdb) list > 11 GNU General Public License for more details. > 12 > 13 You should have received a copy of the GNU General Public License > 14 along with this program. If not, see <http://www.gnu.org/licenses/>. */ > 15 > 16 static int > 17 foo (void) > 18 { > 19 return 0; /* break here */ > 20 } > (gdb) > 21 > 22 int > 23 main (void) > 24 { > 25 return foo (); > 26 } > (gdb) b 19 > No line 19 in the current file. > Make breakpoint pending on future shared library load? (y or [n]) > > The problem here is that when convert_sals_line_offset sets the default s/convert_sals_line_offset/create_sals_line_offset/ > symtab, it immediately calls symtab_to_fullname, passing that fullname > to collect_symtabs_from_filename. > > When we iterate over the compunit_symtabs in iterate_over_some_symtabs, > NAME is this the fullname from symtab_to_fullname while the symtab > filename is the symlink name (gotten from debuginfo). > compare_filenames_for_search is then called to ascertain a match between, > e.g., "symlink.c" and "/path/to/realsource.c". > The first comparison fails (compare_filenames_for_search returns early > with a simple strlen comparison). > > Later in iterate_over_some_symtabs, symtab_to_fullname would be called > with the result of symtab_to_fullname, but only if the user has set This sentence doesn't seem to make sense (symtab_to_fullname twice)? I think you meant something like this: Later in iterate_over_some_symtabs, the passed-in fullname would be compared with the symtab's fullname but only if the user has set > "basenames-may-differ." This flag defaults to "off" because, as > iterate_over_some_symtabs says, realpath is very expensive to use. > > However, there seems little reason not to check the fullname if it is > already known (non-NULL). That's what this patch does. > My first reaction was, why are we doing that, passing down the fullname instead of the symtab's filename, especially considering basenames_may_differ. Pedantically looks odd at first sight. I suppose I don't see a great reason to not chech fullname either, so I guess that's fine. Actually, if create_sals_line_offset has a default symtab handy, why does it need to iterate over symtabs? Couldn't it just use the default directly? > gdb/ChangeLog > > PR symtab/23853 > * symtab.c (iterate_over_some_symtabs): If the symtab has a > fullname, check whether it is a filename match, too. > > gdb/testsuite/ChangeLog > > PR symtab/23853 > * gdb.base/symlink-sourcefile.c: New file. > * gdb.base/symlink-sourcefile.exp: New file. > --- > gdb/ChangeLog | 6 +++ > gdb/symtab.c | 4 +- > gdb/testsuite/ChangeLog | 6 +++ > gdb/testsuite/gdb.base/symlink-sourcefile.c | 26 +++++++++++ > gdb/testsuite/gdb.base/symlink-sourcefile.exp | 44 +++++++++++++++++++ > 5 files changed, 85 insertions(+), 1 deletion(-) > create mode 100644 gdb/testsuite/gdb.base/symlink-sourcefile.c > create mode 100644 gdb/testsuite/gdb.base/symlink-sourcefile.exp > > diff --git a/gdb/ChangeLog b/gdb/ChangeLog > index bc77fe85c7..557c72b203 100644 > --- a/gdb/ChangeLog > +++ b/gdb/ChangeLog > @@ -1,3 +1,9 @@ > +YYYY-MM-DD Keith Seitz <keiths@redhat.com> > + > + PR symtab/23853 > + * symtab.c (iterate_over_some_symtabs): If the symtab has a > + fullname, check whether it is a filename match, too. > + > 2018-11-04 Tom Tromey <tom@tromey.com> > > * varobj.c (install_default_visualizer): Update. > diff --git a/gdb/symtab.c b/gdb/symtab.c > index 7649908d9c..5b39db6d33 100644 > --- a/gdb/symtab.c > +++ b/gdb/symtab.c > @@ -412,7 +412,9 @@ iterate_over_some_symtabs (const char *name, > { > ALL_COMPUNIT_FILETABS (cust, s) > { > - if (compare_filenames_for_search (s->filename, name)) > + if (compare_filenames_for_search (s->filename, name) > + || (s->fullname != nullptr > + && compare_filenames_for_search (s->fullname, name))) This may use a comment. Otherwise a reader is wondering why we're comparing the fullname, when basenames_may_differ is false, which pedantically looks odd at first sight. Also, I'm looking at this wondering about redundant checks and efficiency. I.e., if s->fullname is not NULL and the new check fails above, then this one below: if (compare_filenames_for_search (symtab_to_fullname (s), name)) { ... is guaranteed to fail too, AFAICS. That would suggest tweaking that one to: if (s->fullname == nullptr || compare_filenames_for_search (symtab_to_fullname (s), name)) { then. Right? I noticed that psym_map_symtabs_matching_filename uses the same search algorithm, which looks like should be changed to match. Maybe dw2_map_symtabs_matching_filename and skiplist_entry::do_skip_file_p too. And others. Not sure. I just grepped for basenames_may_differ and found these. > + > +# Test GDB when source files are symlinks. Please mention the specific case of the default symtab somewhere. Either here, or at the gdb_breakpoint line below. That's important for the test, right? > +standard_testfile > + > +set test "file symbolic link name" > +set linksrc "link-${srcfile}" > +set srcfilelink [standard_output_file $linksrc] > + > + > +# Remove any existing symlink and build executable using the > +# symlink. > +remote_file host delete $srcfilelink > +set status [remote_exec host \ > + "ln -sf $srcdir/$subdir/$srcfile $srcfilelink"] > +if {[lindex $status 0] != 0} { > + unsupported "$test (host does not support symbolic links)" > + return 0 > +} > + > +if {[prepare_for_testing $testfile $testfile $srcfilelink]} { > + return -1 > +} > + > +if {![runto_main]} { > + untested "could not run to main" > + return -1 > +} > + > +gdb_breakpoint [gdb_get_line_number "break here" $srcfile] message > +gdb_continue_to_breakpoint "run to breakpoint marker" > Thanks, Pedro Alves
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bc77fe85c7..557c72b203 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +YYYY-MM-DD Keith Seitz <keiths@redhat.com> + + PR symtab/23853 + * symtab.c (iterate_over_some_symtabs): If the symtab has a + fullname, check whether it is a filename match, too. + 2018-11-04 Tom Tromey <tom@tromey.com> * varobj.c (install_default_visualizer): Update. diff --git a/gdb/symtab.c b/gdb/symtab.c index 7649908d9c..5b39db6d33 100644 --- a/gdb/symtab.c +++ b/gdb/symtab.c @@ -412,7 +412,9 @@ iterate_over_some_symtabs (const char *name, { ALL_COMPUNIT_FILETABS (cust, s) { - if (compare_filenames_for_search (s->filename, name)) + if (compare_filenames_for_search (s->filename, name) + || (s->fullname != nullptr + && compare_filenames_for_search (s->fullname, name))) { if (callback (s)) return true; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 0df75aa54f..4befa4f4c9 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +YYYY-MM-DD Keith Seitz <keiths@redhat.com> + + PR symtab/23853 + * gdb.base/symlink-sourcefile.c: New file. + * gdb.base/symlink-sourcefile.exp: New file. + 2018-11-01 Joel Brobecker <brobecker@adacore.com> * gdb.ada/watch_minus_l: New testcase. diff --git a/gdb/testsuite/gdb.base/symlink-sourcefile.c b/gdb/testsuite/gdb.base/symlink-sourcefile.c new file mode 100644 index 0000000000..2cf0d0e2fe --- /dev/null +++ b/gdb/testsuite/gdb.base/symlink-sourcefile.c @@ -0,0 +1,26 @@ +/* Copyright 2018 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +static int +foo (void) +{ + return 0; /* break here */ +} + +int +main (void) +{ + return foo (); +} diff --git a/gdb/testsuite/gdb.base/symlink-sourcefile.exp b/gdb/testsuite/gdb.base/symlink-sourcefile.exp new file mode 100644 index 0000000000..084be07151 --- /dev/null +++ b/gdb/testsuite/gdb.base/symlink-sourcefile.exp @@ -0,0 +1,44 @@ +# Copyright 2018 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +# Test GDB when source files are symlinks. +standard_testfile + +set test "file symbolic link name" +set linksrc "link-${srcfile}" +set srcfilelink [standard_output_file $linksrc] + + +# Remove any existing symlink and build executable using the +# symlink. +remote_file host delete $srcfilelink +set status [remote_exec host \ + "ln -sf $srcdir/$subdir/$srcfile $srcfilelink"] +if {[lindex $status 0] != 0} { + unsupported "$test (host does not support symbolic links)" + return 0 +} + +if {[prepare_for_testing $testfile $testfile $srcfilelink]} { + return -1 +} + +if {![runto_main]} { + untested "could not run to main" + return -1 +} + +gdb_breakpoint [gdb_get_line_number "break here" $srcfile] message +gdb_continue_to_breakpoint "run to breakpoint marker"
This patch attempts to fix a bug dealing with setting breakpoints in default symtabs that are symlinks. For example: (gdb) list 11 GNU General Public License for more details. 12 13 You should have received a copy of the GNU General Public License 14 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 15 16 static int 17 foo (void) 18 { 19 return 0; /* break here */ 20 } (gdb) 21 22 int 23 main (void) 24 { 25 return foo (); 26 } (gdb) b 19 No line 19 in the current file. Make breakpoint pending on future shared library load? (y or [n]) The problem here is that when convert_sals_line_offset sets the default symtab, it immediately calls symtab_to_fullname, passing that fullname to collect_symtabs_from_filename. When we iterate over the compunit_symtabs in iterate_over_some_symtabs, NAME is this the fullname from symtab_to_fullname while the symtab filename is the symlink name (gotten from debuginfo). compare_filenames_for_search is then called to ascertain a match between, e.g., "symlink.c" and "/path/to/realsource.c". The first comparison fails (compare_filenames_for_search returns early with a simple strlen comparison). Later in iterate_over_some_symtabs, symtab_to_fullname would be called with the result of symtab_to_fullname, but only if the user has set "basenames-may-differ." This flag defaults to "off" because, as iterate_over_some_symtabs says, realpath is very expensive to use. However, there seems little reason not to check the fullname if it is already known (non-NULL). That's what this patch does. gdb/ChangeLog PR symtab/23853 * symtab.c (iterate_over_some_symtabs): If the symtab has a fullname, check whether it is a filename match, too. gdb/testsuite/ChangeLog PR symtab/23853 * gdb.base/symlink-sourcefile.c: New file. * gdb.base/symlink-sourcefile.exp: New file. --- gdb/ChangeLog | 6 +++ gdb/symtab.c | 4 +- gdb/testsuite/ChangeLog | 6 +++ gdb/testsuite/gdb.base/symlink-sourcefile.c | 26 +++++++++++ gdb/testsuite/gdb.base/symlink-sourcefile.exp | 44 +++++++++++++++++++ 5 files changed, 85 insertions(+), 1 deletion(-) create mode 100644 gdb/testsuite/gdb.base/symlink-sourcefile.c create mode 100644 gdb/testsuite/gdb.base/symlink-sourcefile.exp