From c5c10118216867e133c132b4f46e19fb6aa9258a Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Thu, 24 Jan 2019 17:31:21 -0700 Subject: [PATCH] Simplify exception handling Now that cleanups have been removed, TRY/CATCH can't be SJLJ-based any more. This patch simplifies the exception handling code, by removing the non-working variants. Note that the "pure" C++ exception handling code is removed as well; I think the route forward must be to change exceptions to be self-destructing, so that try_scope_depth can simply be removed. Some longjmp-based code remains, as it is needed to throw an exception through readline. gdb/ChangeLog 2019-04-08 Tom Tromey * common/common-exceptions.h (GDB_XCPT_SJMP, GDB_XCPT_TRY) (GDB_XCPT_RAW_TRY, GDB_XCPT): Remove. (TRY, CATCH, END_CATCH): Remove some definitions. * common/common-exceptions.c: Don't use GDB_XCPT. (catcher_list_size): Remove. (throw_exception, throw_it): Simplify. --- gdb/ChangeLog | 9 +++++++++ gdb/common/common-exceptions.c | 36 --------------------------------- gdb/common/common-exceptions.h | 46 +----------------------------------------- 3 files changed, 10 insertions(+), 81 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 7d79c81..cc2c270 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2019-04-08 Tom Tromey + + * common/common-exceptions.h (GDB_XCPT_SJMP, GDB_XCPT_TRY) + (GDB_XCPT_RAW_TRY, GDB_XCPT): Remove. + (TRY, CATCH, END_CATCH): Remove some definitions. + * common/common-exceptions.c: Don't use GDB_XCPT. + (catcher_list_size): Remove. + (throw_exception, throw_it): Simplify. + 2019-04-05 Tom Tromey Revert the header-sorting patch. diff --git a/gdb/common/common-exceptions.c b/gdb/common/common-exceptions.c index 4e67e89..c3529c9 100644 --- a/gdb/common/common-exceptions.c +++ b/gdb/common/common-exceptions.c @@ -54,26 +54,6 @@ struct catcher /* Where to go for throw_exception(). */ static struct catcher *current_catcher; -#if GDB_XCPT == GDB_XCPT_SJMP - -/* Return length of current_catcher list. */ - -static int -catcher_list_size (void) -{ - int size; - struct catcher *catcher; - - for (size = 0, catcher = current_catcher; - catcher != NULL; - catcher = catcher->prev) - ++size; - - return size; -} - -#endif - jmp_buf * exceptions_state_mc_init (void) { @@ -205,8 +185,6 @@ exceptions_state_mc_action_iter_1 (void) return exceptions_state_mc (CATCH_ITER_1); } -#if GDB_XCPT != GDB_XCPT_SJMP - /* How many nested TRY blocks we have. See exception_messages and throw_it. */ @@ -248,8 +226,6 @@ gdb_exception_sliced_copy (struct gdb_exception *to, const struct gdb_exception *to = *from; } -#endif /* !GDB_XCPT_SJMP */ - /* Return EXCEPTION to the nearest containing CATCH_SJLJ block. */ void @@ -263,8 +239,6 @@ throw_exception_sjlj (struct gdb_exception exception) longjmp (current_catcher->buf, exception.reason); } -#if GDB_XCPT != GDB_XCPT_SJMP - /* Implementation of throw_exception that uses C++ try/catch. */ static ATTRIBUTE_NORETURN void @@ -288,16 +262,10 @@ throw_exception_cxx (struct gdb_exception exception) gdb_assert_not_reached ("invalid return reason"); } -#endif - void throw_exception (struct gdb_exception exception) { -#if GDB_XCPT == GDB_XCPT_SJMP - throw_exception_sjlj (exception); -#else throw_exception_cxx (exception); -#endif } /* A stack of exception messages. @@ -321,11 +289,7 @@ throw_it (enum return_reason reason, enum errors error, const char *fmt, { struct gdb_exception e; char *new_message; -#if GDB_XCPT == GDB_XCPT_SJMP - int depth = catcher_list_size (); -#else int depth = try_scope_depth; -#endif gdb_assert (depth > 0); diff --git a/gdb/common/common-exceptions.h b/gdb/common/common-exceptions.h index 471e7c5..6cc09ea 100644 --- a/gdb/common/common-exceptions.h +++ b/gdb/common/common-exceptions.h @@ -115,22 +115,6 @@ struct gdb_exception const char *message; }; -/* The different exception mechanisms that TRY/CATCH can map to. */ - -/* Make GDB exceptions use setjmp/longjmp behind the scenes. */ -#define GDB_XCPT_SJMP 1 - -/* Make GDB exceptions use try/catch behind the scenes. */ -#define GDB_XCPT_TRY 2 - -/* Specify this mode to build with TRY/CATCH mapped directly to raw - try/catch. GDB won't work correctly, but building that way catches - code tryin to break/continue out of the try block, along with - spurious code between the TRY and the CATCH block. */ -#define GDB_XCPT_RAW_TRY 3 - -#define GDB_XCPT GDB_XCPT_TRY - /* Functions to drive the sjlj-based exceptions state machine. Though declared here by necessity, these functions should be considered internal to the exceptions subsystem and not used other than via @@ -141,13 +125,11 @@ 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); -/* Same, but for the C++ try/catch-based TRY/CATCH mechanism. */ +/* For the C++ try/catch-based TRY/CATCH mechanism. */ -#if GDB_XCPT != GDB_XCPT_SJMP extern void *exception_try_scope_entry (void); extern void exception_try_scope_exit (void *saved_state); extern void exception_rethrow (void) ATTRIBUTE_NORETURN; -#endif /* Macro to wrap up standard try/catch behavior. @@ -196,19 +178,6 @@ extern void exception_rethrow (void) ATTRIBUTE_NORETURN; #define END_CATCH_SJLJ \ } -#if GDB_XCPT == GDB_XCPT_SJMP - -/* If using SJLJ-based exceptions for all exceptions, then provide - standard aliases. */ - -#define TRY TRY_SJLJ -#define CATCH CATCH_SJLJ -#define END_CATCH END_CATCH_SJLJ - -#endif /* GDB_XCPT_SJMP */ - -#if GDB_XCPT == GDB_XCPT_TRY || GDB_XCPT == GDB_XCPT_RAW_TRY - /* Prevent error/quit during TRY from calling cleanups established prior to here. This pops out the scope in either case of normal exit or exception exit. */ @@ -226,8 +195,6 @@ struct exception_try_scope void *saved_state; }; -#if GDB_XCPT == GDB_XCPT_TRY - /* We still need to wrap TRY/CATCH in C++ so that cleanups and C++ exceptions can coexist. @@ -263,15 +230,6 @@ struct exception_try_scope } \ } -#else - -#define TRY try -#define CATCH(EXCEPTION, MASK) \ - catch (struct gdb_exception ## _ ## MASK &EXCEPTION) -#define END_CATCH - -#endif - /* The exception types client code may catch. They're just shims around gdb_exception that add nothing but type info. Which is used is selected depending on the MASK argument passed to CATCH. */ @@ -288,8 +246,6 @@ struct gdb_exception_RETURN_MASK_QUIT : public gdb_exception_RETURN_MASK_ALL { }; -#endif /* GDB_XCPT_TRY || GDB_XCPT_RAW_TRY */ - /* An exception type that inherits from both std::bad_alloc and a gdb exception. This is necessary because operator new can only throw std::bad_alloc, and OTOH, we want exceptions thrown due to memory -- 2.7.4