From 30af7c7fa13e17d82c3f1f91536384715844f432 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Wed, 11 Nov 2020 11:59:11 +0100 Subject: struct _Unwind_Exception alignment should not depend on compiler flags __attribute__((__aligned__)) selects an alignment that depends on the micro-architecture selected by GCC flags. Enabling vector extensions may increase the allignment. This is a problem when building glibc as a collection of ELF multilibs with different GCC flags because ld.so and libc.so/libpthread.so/&c may end up with a different layout of struct pthread because of the changing offset of its struct _Unwind_Exception field. Tested-By: Matheus Castanho --- sysdeps/generic/unwind.h | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/sysdeps/generic/unwind.h b/sysdeps/generic/unwind.h index b667a5b652..c229603af3 100644 --- a/sysdeps/generic/unwind.h +++ b/sysdeps/generic/unwind.h @@ -75,15 +75,21 @@ typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code, struct _Unwind_Exception { - _Unwind_Exception_Class exception_class; - _Unwind_Exception_Cleanup_Fn exception_cleanup; - _Unwind_Word private_1; - _Unwind_Word private_2; - - /* @@@ The IA-64 ABI says that this structure must be double-word aligned. - Taking that literally does not make much sense generically. Instead we - provide the maximum alignment required by any type for the machine. */ -} __attribute__((__aligned__)); + union + { + struct + { + _Unwind_Exception_Class exception_class; + _Unwind_Exception_Cleanup_Fn exception_cleanup; + _Unwind_Word private_1; + _Unwind_Word private_2; + }; + + /* The IA-64 ABI says that this structure must be double-word aligned. */ + _Unwind_Word unwind_exception_align[2] + __attribute__ ((__aligned__ (2 * sizeof (_Unwind_Word)))); + }; +}; /* The ACTIONS argument to the personality routine is a bitwise OR of one -- cgit 1.4.1