From 173981bc49c9e8fce9271cb47714952dbe2ec627 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 12 Apr 2016 17:20:04 +0100 Subject: [PATCH] Use setjmp/longjmp for TRY/CATCH instead of sigsetjmp/siglongjmp Now that we don't ever throw GDB exceptions from signal handlers [1], we can switch to have TRY/CATCH implemented in terms of plain setjmp/longjmp instead of sigsetjmp/siglongjmp. In https://sourceware.org/ml/gdb-patches/2015-02/msg00114.html, Yichun Zhang mentions a 11%/14%+ speedup in his GDB python scripts with a patch that did something similar to only a specific set of TRY/CATCH calls. [1] - https://sourceware.org/ml/gdb-patches/2016-03/msg00351.html Tested on x86_64 Fedora 23, native and gdbserver. gdb/ChangeLog: 2016-04-12 Pedro Alves * common/common-exceptions.c (struct catcher) : Now a 'jmp_buf' instead of SIGJMP_BUF. (exceptions_state_mc_init): Change return type to 'jmp_buf'. (throw_exception): Use longjmp instead of SIGLONGJMP. * common/common-exceptions.h: Include instead of "gdb_setjmp.h". (exceptions_state_mc_init): Change return type to 'jmp_buf'. [GDB_XCPT == GDB_XCPT_SJMP] (TRY): Use setjmp instead of SIGSETJMP. * cp-support.c: Include "gdb_setjmp.h". --- gdb/ChangeLog | 13 +++++++++++++ gdb/common/common-exceptions.c | 6 +++--- gdb/common/common-exceptions.h | 8 ++++---- gdb/cp-support.c | 2 +- 4 files changed, 21 insertions(+), 8 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 5dfd4b0..b750266 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,18 @@ 2016-04-12 Pedro Alves + * common/common-exceptions.c (struct catcher) : Now a + 'jmp_buf' instead of SIGJMP_BUF. + (exceptions_state_mc_init): Change return type to 'jmp_buf'. + (throw_exception): Use longjmp instead of SIGLONGJMP. + * common/common-exceptions.h: Include instead of + "gdb_setjmp.h". + (exceptions_state_mc_init): Change return type to 'jmp_buf'. + [GDB_XCPT == GDB_XCPT_SJMP] (TRY): Use setjmp instead of + SIGSETJMP. + * cp-support.c: Include "gdb_setjmp.h". + +2016-04-12 Pedro Alves + * common/common-exceptions.c (exception_rethrow): Remove prepare_to_throw_exception call. * common/common-exceptions.h (prepare_to_throw_exception): Delete diff --git a/gdb/common/common-exceptions.c b/gdb/common/common-exceptions.c index 5ea8188..2e63862 100644 --- a/gdb/common/common-exceptions.c +++ b/gdb/common/common-exceptions.c @@ -46,7 +46,7 @@ struct catcher { enum catcher_state state; /* Jump buffer pointing back at the exception handler. */ - SIGJMP_BUF buf; + jmp_buf buf; /* Status buffer belonging to the exception handler. */ struct gdb_exception exception; struct cleanup *saved_cleanup_chain; @@ -73,7 +73,7 @@ catcher_list_size (void) return size; } -SIGJMP_BUF * +jmp_buf * exceptions_state_mc_init (void) { struct catcher *new_catcher = XCNEW (struct catcher); @@ -275,7 +275,7 @@ throw_exception (struct gdb_exception exception) be zero, by definition in defs.h. */ exceptions_state_mc (CATCH_THROWING); current_catcher->exception = exception; - SIGLONGJMP (current_catcher->buf, exception.reason); + longjmp (current_catcher->buf, exception.reason); #else if (exception.reason == RETURN_QUIT) { diff --git a/gdb/common/common-exceptions.h b/gdb/common/common-exceptions.h index 54c6249..e21713c 100644 --- a/gdb/common/common-exceptions.h +++ b/gdb/common/common-exceptions.h @@ -20,7 +20,7 @@ #ifndef COMMON_EXCEPTIONS_H #define COMMON_EXCEPTIONS_H -#include "gdb_setjmp.h" +#include /* Reasons for calling throw_exceptions(). NOTE: all reason values must be less than zero. enum value 0 is reserved for internal use @@ -142,7 +142,7 @@ struct gdb_exception macros defined below. */ #if GDB_XCPT == GDB_XCPT_SJMP -extern SIGJMP_BUF *exceptions_state_mc_init (void); +extern jmp_buf *exceptions_state_mc_init (void); extern int exceptions_state_mc_action_iter (void); extern int exceptions_state_mc_action_iter_1 (void); extern int exceptions_state_mc_catch (struct gdb_exception *, int); @@ -181,9 +181,9 @@ extern void exception_rethrow (void); #define TRY \ { \ - SIGJMP_BUF *buf = \ + jmp_buf *buf = \ exceptions_state_mc_init (); \ - SIGSETJMP (*buf); \ + setjmp (*buf); \ } \ while (exceptions_state_mc_action_iter ()) \ while (exceptions_state_mc_action_iter_1 ()) diff --git a/gdb/cp-support.c b/gdb/cp-support.c index c7f5074..5662f86 100644 --- a/gdb/cp-support.c +++ b/gdb/cp-support.c @@ -34,7 +34,7 @@ #include "cp-abi.h" #include "namespace.h" #include - +#include "gdb_setjmp.h" #include "safe-ctype.h" #define d_left(dc) (dc)->u.s_binary.left -- 2.7.4