From 5d28a8962dcb6ec056b81d730e3c6fb57185a210 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 28 Dec 2021 22:52:56 +0100 Subject: elf: Add _dl_find_object function It can be used to speed up the libgcc unwinder, and the internal _dl_find_dso_for_object function (which is used for caller identification in dlopen and related functions, and in dladdr). _dl_find_object is in the internal namespace due to bug 28503. If libgcc switches to _dl_find_object, this namespace issue will be fixed. It is located in libc for two reasons: it is necessary to forward the call to the static libc after static dlopen, and there is a link ordering issue with -static-libgcc and libgcc_eh.a because libc.so is not a linker script that includes ld.so in the glibc build tree (so that GCC's internal -lc after libgcc_eh.a does not pick up ld.so). It is necessary to do the i386 customization in the sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because otherwise, multilib installations are broken. The implementation uses software transactional memory, as suggested by Torvald Riegel. Two copies of the supporting data structures are used, also achieving full async-signal-safety. Reviewed-by: Adhemerval Zanella --- elf/tst-dl_find_object-mod6.c | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 elf/tst-dl_find_object-mod6.c (limited to 'elf/tst-dl_find_object-mod6.c') diff --git a/elf/tst-dl_find_object-mod6.c b/elf/tst-dl_find_object-mod6.c new file mode 100644 index 0000000000..f78acffb9e --- /dev/null +++ b/elf/tst-dl_find_object-mod6.c @@ -0,0 +1,11 @@ +/* Large to get different layouts. */ +char mod6_data[4096]; + +void +mod6_function (void (*f) (void)) +{ + /* Make sure this is not a tail call and unwind information is + therefore needed. */ + f (); + f (); +} -- cgit 1.4.1