/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
- Copyright (C) 1986-2015 Free Software Foundation, Inc.
+ Copyright (C) 1986-2019 Free Software Foundation, Inc.
This file is part of GDB.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifndef COMMON_EXCEPTIONS_H
-#define COMMON_EXCEPTIONS_H
+#ifndef COMMON_COMMON_EXCEPTIONS_H
+#define COMMON_COMMON_EXCEPTIONS_H
-#include "gdb_setjmp.h"
+#include <setjmp.h>
+#include <new>
+#include <memory>
+#include <string>
/* Reasons for calling throw_exceptions(). NOTE: all reason values
- must be less than zero. enum value 0 is reserved for internal use
- as the return value from an initial setjmp(). The function
- catch_exceptions() reserves values >= 0 as legal results from its
- wrapped function. */
+ must be different from zero. enum value 0 is reserved for internal
+ use as the return value from an initial setjmp(). */
enum return_reason
{
means the register was not saved in the frame. */
OPTIMIZED_OUT_ERROR,
- /* DW_OP_GNU_entry_value resolving failed. */
+ /* DW_OP_entry_value resolving failed. */
NO_ENTRY_VALUE_ERROR,
/* Target throwing an error has been closed. Current command should be
/* Requested feature, method, mechanism, etc. is not supported. */
NOT_SUPPORTED_ERROR,
+ /* The number of candidates generated during line completion has
+ reached the user's specified limit. This isn't an error, this exception
+ is used to halt searching for more completions, but for consistency
+ "_ERROR" is appended to the name. */
+ MAX_COMPLETIONS_REACHED_ERROR,
+
/* Add more errors here. */
NR_ERRORS
};
struct gdb_exception
{
+ gdb_exception ()
+ : reason ((enum return_reason) 0),
+ error (GDB_NO_ERROR)
+ {
+ }
+
+ gdb_exception (enum return_reason r, enum errors e)
+ : reason (r),
+ error (e)
+ {
+ }
+
+ gdb_exception (enum return_reason r, enum errors e,
+ const char *fmt, va_list ap)
+ ATTRIBUTE_PRINTF (4, 0)
+ : reason (r),
+ error (e),
+ message (std::make_shared<std::string> (string_vprintf (fmt, ap)))
+ {
+ }
+
+ /* The copy constructor exists so that we can mark it "noexcept",
+ which is a good practice for any sort of exception object. */
+ gdb_exception (const gdb_exception &other) noexcept
+ : reason (other.reason),
+ error (other.error),
+ message (other.message)
+ {
+ }
+
+ /* The assignment operator exists so that we can mark it "noexcept",
+ which is a good practice for any sort of exception object. */
+ gdb_exception &operator= (const gdb_exception &other) noexcept
+ {
+ reason = other.reason;
+ error = other.error;
+ message = other.message;
+ return *this;
+ }
+
+ gdb_exception &operator= (gdb_exception &&other) noexcept = default;
+
+ /* Return the contents of the exception message, as a C string. The
+ string remains owned by the exception object. */
+ const char *what () const noexcept
+ {
+ return message->c_str ();
+ }
+
enum return_reason reason;
enum errors error;
- const char *message;
+ std::shared_ptr<std::string> message;
};
-/* Functions to drive the exceptions state machine. Though declared
- here by necessity, these functions should be considered internal to
- the exceptions subsystem and not used other than via the TRY_CATCH
- macro defined below. */
+/* 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
+ the TRY/CATCH (or TRY_SJLJ/CATCH_SJLJ) macros defined below. */
-extern SIGJMP_BUF *exceptions_state_mc_init (volatile struct
- gdb_exception *exception,
- return_mask mask);
+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);
/* Macro to wrap up standard try/catch behavior.
*INDENT-OFF*
- volatile struct gdb_exception e;
- TRY_CATCH (e, RETURN_MASK_ERROR)
+ TRY_SJLJ
{
}
- switch (e.reason)
+ CATCH_SJLJ (e, RETURN_MASK_ERROR)
{
- case RETURN_ERROR: ...
+ switch (e.reason)
+ {
+ case RETURN_ERROR: ...
+ }
}
+ END_CATCH_SJLJ
- */
+ The SJLJ variants are needed in some cases where gdb exceptions
+ need to cross third-party library code compiled without exceptions
+ support (e.g., readline). */
-#define TRY_CATCH(EXCEPTION,MASK) \
+#define TRY_SJLJ \
{ \
- SIGJMP_BUF *buf = \
- exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
- SIGSETJMP (*buf); \
+ jmp_buf *buf = \
+ exceptions_state_mc_init (); \
+ setjmp (*buf); \
} \
while (exceptions_state_mc_action_iter ()) \
while (exceptions_state_mc_action_iter_1 ())
-/* *INDENT-ON* */
+#define CATCH_SJLJ(EXCEPTION, MASK) \
+ { \
+ struct gdb_exception EXCEPTION; \
+ if (exceptions_state_mc_catch (&(EXCEPTION), MASK))
-/* Hook to allow client-specific actions to be performed prior to
- throwing an exception. This function must be provided by the
- client, and will be called before any cleanups are run. */
+#define END_CATCH_SJLJ \
+ }
-extern void prepare_to_throw_exception (void);
+/* 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. */
-/* Throw an exception (as described by "struct gdb_exception"). Will
- execute a LONG JUMP to the inner most containing exception handler
- established using catch_exceptions() (or similar).
+struct gdb_exception_error : public gdb_exception
+{
+ gdb_exception_error (enum errors e, const char *fmt, va_list ap)
+ ATTRIBUTE_PRINTF (3, 0)
+ : gdb_exception (RETURN_ERROR, e, fmt, ap)
+ {
+ }
- Code normally throws an exception using error() et.al. For various
- reaons, GDB also contains code that throws an exception directly.
- For instance, the remote*.c targets contain CNTRL-C signal handlers
- that propogate the QUIT event up the exception chain. ``This could
- be a good thing or a dangerous thing.'' -- the Existential
- Wombat. */
+ explicit gdb_exception_error (const gdb_exception &ex) noexcept
+ : gdb_exception (ex)
+ {
+ gdb_assert (ex.reason == RETURN_ERROR);
+ }
+};
-extern void throw_exception (struct gdb_exception exception)
+struct gdb_exception_quit : public gdb_exception
+{
+ gdb_exception_quit (const char *fmt, va_list ap)
+ ATTRIBUTE_PRINTF (2, 0)
+ : gdb_exception (RETURN_QUIT, GDB_NO_ERROR, fmt, ap)
+ {
+ }
+
+ explicit gdb_exception_quit (const gdb_exception &ex) noexcept
+ : gdb_exception (ex)
+ {
+ gdb_assert (ex.reason == RETURN_QUIT);
+ }
+};
+
+/* 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
+ allocation error to be caught by all the CATCH/RETURN_MASK_ALL
+ spread around the codebase. */
+
+struct gdb_quit_bad_alloc
+ : public gdb_exception_quit,
+ public std::bad_alloc
+{
+ explicit gdb_quit_bad_alloc (const gdb_exception &ex) noexcept
+ : gdb_exception_quit (ex),
+ std::bad_alloc ()
+ {
+ }
+};
+
+/* *INDENT-ON* */
+
+/* Throw an exception (as described by "struct gdb_exception"),
+ landing in the inner most containing exception handler established
+ using TRY/CATCH. */
+extern void throw_exception (const gdb_exception &exception)
+ ATTRIBUTE_NORETURN;
+
+/* Throw an exception by executing a LONG JUMP to the inner most
+ containing exception handler established using TRY_SJLJ. Necessary
+ in some cases where we need to throw GDB exceptions across
+ third-party library code (e.g., readline). */
+extern void throw_exception_sjlj (const struct gdb_exception &exception)
ATTRIBUTE_NORETURN;
+
+/* Convenience wrappers around throw_exception that throw GDB
+ errors. */
extern void throw_verror (enum errors, const char *fmt, va_list ap)
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
extern void throw_vquit (const char *fmt, va_list ap)
extern void throw_quit (const char *fmt, ...)
ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
-#endif /* COMMON_EXCEPTIONS_H */
+#endif /* COMMON_COMMON_EXCEPTIONS_H */
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