| Message ID | 20240306215435.914126-3-morten@linderud.pw |
|---|---|
| State | New |
| Headers | show |
| Series | lto-streamer: Ensure src_pwd is remapped | expand |
On Wed, Mar 6, 2024 at 10:56 PM Morten Linderud <morten@linderud.pw> wrote: > > I've made an attempt at patching this issue as it produces unreproducible > unreproducible binaries for Golang. I don't know C/C++ and it's my first gcc > patch so please bear with me :) I think this is a very fragile area - see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109805 I would first appreciate an attempt to add testsuite coverage for using any of the -f*-map switches with LTO, esp. when multiple TUs are involved, possibly different switches for different TUs at compile-time and with or without such switches at link time. Alternatively at least trying to document the expected behavior in these circumstances. I'll note your patch applies one set of remapping at TU compile time while the other is applied at link time where it's not clear how it will behave if those ever get out-of-sync. It's also not clear why you need to remap both times or whether the 'src_pwd' should have been remapped. As said, a fragile (and known broken to some extent) area. Thanks, Richard. > -- >8 -- > > When -flto is used with line macros containing bare symbols instead of > absolute paths the full path is added but never remapped with > -ffile-prefix-map. This could produce unreproducible binaries. > > Fixes: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108534 > > Signed-off-by: Morten Linderud <morten@linderud.pw> > --- > gcc/lto-streamer-in.cc | 6 ++++-- > gcc/lto-streamer-out.cc | 6 ++++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/gcc/lto-streamer-in.cc b/gcc/lto-streamer-in.cc > index ad0ca24007a..799f9eec478 100644 > --- a/gcc/lto-streamer-in.cc > +++ b/gcc/lto-streamer-in.cc > @@ -44,6 +44,7 @@ along with GCC; see the file COPYING3. If not see > #include "debug.h" > #include "alloc-pool.h" > #include "toplev.h" > +#include "file-prefix-map.h" /* remap_debug_filename() */ > > /* Allocator used to hold string slot entries for line map streaming. */ > static struct object_allocator<struct string_slot> *string_slot_allocator; > @@ -557,11 +558,12 @@ lto_location_cache::input_location_and_block (location_t *loc, > { > const char *pwd = bp_unpack_string (data_in, bp); > const char *src_pwd = get_src_pwd (); > - if (strcmp (pwd, src_pwd) == 0) > + const char *remapped_src_pwd = remap_debug_filename (src_pwd); > + if (strcmp (pwd, remapped_src_pwd) == 0) > stream_relative_path_prefix = NULL; > else > stream_relative_path_prefix > - = canon_relative_path_prefix (pwd, src_pwd); > + = canon_relative_path_prefix (pwd, remapped_src_pwd); > } > stream_file = canon_file_name (stream_relative_path_prefix, > bp_unpack_string (data_in, bp)); > diff --git a/gcc/lto-streamer-out.cc b/gcc/lto-streamer-out.cc > index d4f728094ed..379e256a1e7 100644 > --- a/gcc/lto-streamer-out.cc > +++ b/gcc/lto-streamer-out.cc > @@ -230,8 +230,10 @@ lto_output_location_1 (struct output_block *ob, struct bitpack_d *bp, > ob->emit_pwd = false; > } > bp_pack_value (bp, stream_pwd, 1); > - if (stream_pwd) > - bp_pack_string (ob, bp, get_src_pwd (), true); > + if (stream_pwd){ > + const char *remapped_pwd = remap_debug_filename (get_src_pwd ()); > + bp_pack_string (ob, bp, remapped_pwd, true); > + } > bp_pack_string (ob, bp, remapped, true); > bp_pack_value (bp, xloc.sysp, 1); > } > -- > 2.44.0
diff --git a/gcc/lto-streamer-in.cc b/gcc/lto-streamer-in.cc index ad0ca24007a..799f9eec478 100644 --- a/gcc/lto-streamer-in.cc +++ b/gcc/lto-streamer-in.cc @@ -44,6 +44,7 @@ along with GCC; see the file COPYING3. If not see #include "debug.h" #include "alloc-pool.h" #include "toplev.h" +#include "file-prefix-map.h" /* remap_debug_filename() */ /* Allocator used to hold string slot entries for line map streaming. */ static struct object_allocator<struct string_slot> *string_slot_allocator; @@ -557,11 +558,12 @@ lto_location_cache::input_location_and_block (location_t *loc, { const char *pwd = bp_unpack_string (data_in, bp); const char *src_pwd = get_src_pwd (); - if (strcmp (pwd, src_pwd) == 0) + const char *remapped_src_pwd = remap_debug_filename (src_pwd); + if (strcmp (pwd, remapped_src_pwd) == 0) stream_relative_path_prefix = NULL; else stream_relative_path_prefix - = canon_relative_path_prefix (pwd, src_pwd); + = canon_relative_path_prefix (pwd, remapped_src_pwd); } stream_file = canon_file_name (stream_relative_path_prefix, bp_unpack_string (data_in, bp)); diff --git a/gcc/lto-streamer-out.cc b/gcc/lto-streamer-out.cc index d4f728094ed..379e256a1e7 100644 --- a/gcc/lto-streamer-out.cc +++ b/gcc/lto-streamer-out.cc @@ -230,8 +230,10 @@ lto_output_location_1 (struct output_block *ob, struct bitpack_d *bp, ob->emit_pwd = false; } bp_pack_value (bp, stream_pwd, 1); - if (stream_pwd) - bp_pack_string (ob, bp, get_src_pwd (), true); + if (stream_pwd){ + const char *remapped_pwd = remap_debug_filename (get_src_pwd ()); + bp_pack_string (ob, bp, remapped_pwd, true); + } bp_pack_string (ob, bp, remapped, true); bp_pack_value (bp, xloc.sysp, 1); }
I've made an attempt at patching this issue as it produces unreproducible unreproducible binaries for Golang. I don't know C/C++ and it's my first gcc patch so please bear with me :) -- >8 -- When -flto is used with line macros containing bare symbols instead of absolute paths the full path is added but never remapped with -ffile-prefix-map. This could produce unreproducible binaries. Fixes: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108534 Signed-off-by: Morten Linderud <morten@linderud.pw> --- gcc/lto-streamer-in.cc | 6 ++++-- gcc/lto-streamer-out.cc | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-)