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| author | Christian Biesinger <cbiesinger@google.com> | 2021-03-09 08:16:23 -0600 |
|---|---|---|
| committer | Christian Biesinger <cbiesinger@google.com> | 2021-03-12 11:21:42 -0600 |
| commit | fece451c2aca57b095e7e4063e342781cf74aa75 (patch) | |
| tree | b1b52ba0a7f3399f65b4b416bc4af7f8ad7b754b /gdb/event-top.h | |
| parent | be3b926d8d2dde16a55e9e303fadf95164e13ebf (diff) | |
| download | gdb-fece451c2aca57b095e7e4063e342781cf74aa75.zip gdb-fece451c2aca57b095e7e4063e342781cf74aa75.tar.gz gdb-fece451c2aca57b095e7e4063e342781cf74aa75.tar.bz2 | |
Use RAII to set the per-thread SIGSEGV handler
This avoids using a thread-local extern variable, which causes link errors
on some platforms, notably Cygwin. But I think this is a better pattern
even outside of working around linker bugs because it encapsulates direct
access to the variable inside the class, instead of having a global extern
variable.
The cygwin link error is:
cp-support.o: in function `gdb_demangle(char const*, int)':
/home/Christian/binutils-gdb/obj/gdb/../../gdb/cp-support.c:1619:(.text+0x6472): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `TLS init function for thread_local_segv_handler'
/home/Christian/binutils-gdb/obj/gdb/../../gdb/cp-support.c:1619:(.text+0x648b): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `TLS init function for thread_local_segv_handler'
collect2: error: ld returned 1 exit status
2021-03-12 Christian Biesinger <cbiesinger@google.com>
PR threads/27239
* cp-support.c: Use scoped_segv_handler_restore.
* event-top.c (thread_local_segv_handler): Made static.
(scoped_segv_handler_restore::scoped_segv_handler_restore):
New function.
(scoped_segv_handler_restore::~scoped_segv_handler_restore): New
function.
* event-top.h (class scoped_segv_handler_restore): New class.
(thread_local_segv_handler): Removed.
Diffstat (limited to 'gdb/event-top.h')
| -rw-r--r-- | gdb/event-top.h | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/gdb/event-top.h b/gdb/event-top.h index c52826e..b036f13 100644 --- a/gdb/event-top.h +++ b/gdb/event-top.h @@ -70,10 +70,19 @@ extern void gdb_rl_callback_handler_install (const char *prompt); currently installed. */ extern void gdb_rl_callback_handler_reinstall (void); -/* The SIGSEGV handler for this thread, or NULL if there is none. GDB - always installs a global SIGSEGV handler, and then lets threads - indicate their interest in handling the signal by setting this - thread-local variable. */ -extern thread_local void (*thread_local_segv_handler) (int); +typedef void (*segv_handler_t) (int); + +/* On construction, replaces the current thread's SIGSEGV handler with + the provided one. On destruction, restores the handler to the + original one. */ +class scoped_segv_handler_restore +{ + public: + scoped_segv_handler_restore (segv_handler_t new_handler); + ~scoped_segv_handler_restore (); + + private: + segv_handler_t m_old_handler; +}; #endif |