[pushed] Add missing-END_CATCH detection/protection (to gdb's TRY/CATCH/END_CATCH)
Commit Message
While we still have cleanups (i.e., make_cleanup & co), we must be
sure to add END_CATCH at the end of a TRY/CATCH/END_CATCH construct.
However, it's currently too easy to miss adding the END_CATCH, because
the code compiles anyway without it. I realized this when I noticed
that another patch I was working on missed several adding END_CATCH in
several new TRY/CATCH uses.
This commit fixes that by making TRY open a new scope that is only
closed by END_CATCH. This way, if you forget to add the END_CATCH,
then compilation fails due to the unbalanced curly braces.
This caught a couple places where we were missing END_CATCH in current
master, also fixed by the patch.
gdb/ChangeLog:
2017-10-04 Pedro Alves <palves@redhat.com>
* cli/cli-cmds.c (complete_command): Add missing END_CATCH.
* common/common-exceptions.h (TRY): Open an outermost scope.
Expand intro comment.
(CATCH): Reindent.
(END_CATCH): Close the outermost scope.
* completer.c (complete_line_internal): Add missing END_CATCH.
---
gdb/cli/cli-cmds.c | 1 +
gdb/common/common-exceptions.h | 41 +++++++++++++++++++++++++++--------------
gdb/completer.c | 1 +
3 files changed, 29 insertions(+), 14 deletions(-)
@@ -296,6 +296,7 @@ complete_command (char *arg_entry, int from_tty)
{
return;
}
+ END_CATCH
std::string arg_prefix (arg, word - arg);
@@ -231,25 +231,38 @@ struct exception_try_scope
#if GDB_XCPT == GDB_XCPT_TRY
/* We still need to wrap TRY/CATCH in C++ so that cleanups and C++
- exceptions can coexist. The TRY blocked is wrapped in a
- do/while(0) so that break/continue within the block works the same
- as in C. */
+ exceptions can coexist.
+
+ The TRY blocked is wrapped in a do/while(0) so that break/continue
+ within the block works the same as in C.
+
+ END_CATCH makes sure that even if the CATCH block doesn't want to
+ catch the exception, we stop at every frame in the unwind chain to
+ run its cleanups, which may e.g., have pointers to stack variables
+ that are going to be destroyed.
+
+ There's an outer scope around the whole TRY/END_CATCH in order to
+ cause a compilation error if you forget to add the END_CATCH at the
+ end a TRY/CATCH construct. */
+
#define TRY \
- try \
- { \
- exception_try_scope exception_try_scope_instance; \
- do \
- {
+ { \
+ try \
+ { \
+ exception_try_scope exception_try_scope_instance; \
+ do \
+ {
#define CATCH(EXCEPTION, MASK) \
- } while (0); \
- } \
- catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
+ } while (0); \
+ } \
+ catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
#define END_CATCH \
- catch (...) \
- { \
- exception_rethrow (); \
+ catch (...) \
+ { \
+ exception_rethrow (); \
+ } \
}
#else
@@ -1447,6 +1447,7 @@ complete_line_internal (completion_tracker &tracker,
if (except.error != MAX_COMPLETIONS_REACHED_ERROR)
throw_exception (except);
}
+ END_CATCH
}
/* See completer.h. */