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Avoid undefined behavior in Guile exception handling

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The Guile code will longjmp (via scm_throw) when an object requiring
destruction is on the stack.  This is undefined behavior.

This changes this code to run any destructors in inner scopes, and to
pass a POD to gdbscm_throw_gdb_exception.

gdb/ChangeLog
2019-04-25  Tom Tromey  <tromey@adacore.com>

	* guile/scm-exception.c (gdbscm_scm_from_gdb_exception)
	(gdbscm_throw_gdb_exception): Take a gdbscm_gdb_exception.
	* guile/scm-block.c, guile/scm-breakpoint.c, guile/scm-cmd.c,
	guile/scm-disasm.c, guile/scm-frame.c, guile/scm-lazy-string.c,
	guile/scm-math.c, guile/scm-param.c, guile/scm-ports.c,
	guile/scm-symbol.c, guile/scm-symtab.c, guile/scm-type.c,
	guile/scm-value.c: Use unpack.
	* guile/guile-internal.h (gdbscm_scm_from_gdb_exception): Take a
	gdbscm_gdb_exception.
	(gdbscm_throw_gdb_exception): Likewise.
	(struct gdbscm_gdb_exception): New.
	(unpack): New function.
	(gdbscm_wrap): Use unpack.
This commit is contained in:
Tom Tromey 2019-04-24 06:50:01 -06:00
parent c6fdd8b205
commit 680d7fd5fc
16 changed files with 235 additions and 82 deletions
Download patch file Download diff file Expand all files Collapse all files

38
gdb/guile/guile-internal.h
View file

@ -353,9 +353,11 @@ extern void gdbscm_misc_error (const char *subr, int arg_pos,
extern void gdbscm_throw (SCM exception) ATTRIBUTE_NORETURN;
extern SCM gdbscm_scm_from_gdb_exception (struct gdb_exception exception);
struct gdbscm_gdb_exception;
extern SCM gdbscm_scm_from_gdb_exception
(const gdbscm_gdb_exception &exception);
extern void gdbscm_throw_gdb_exception (struct gdb_exception exception)
extern void gdbscm_throw_gdb_exception (gdbscm_gdb_exception exception)
ATTRIBUTE_NORETURN;
extern void gdbscm_print_exception_with_stack (SCM port, SCM stack,
@ -650,6 +652,33 @@ extern void gdbscm_initialize_values (void);
with a TRY/CATCH, because the dtors won't otherwise be run when a
Guile exceptions is thrown. */
/* This is a destructor-less clone of gdb_exception. */
struct gdbscm_gdb_exception
{
enum return_reason reason;
enum errors error;
/* The message is xmalloc'd. */
char *message;
};
/* Return a gdbscm_gdb_exception representing EXC. */
inline gdbscm_gdb_exception
unpack (const gdb_exception &exc)
{
gdbscm_gdb_exception result;
result.reason = exc.reason;
result.error = exc.error;
if (exc.message == nullptr)
result.message = nullptr;
else
result.message = xstrdup (exc.message->c_str ());
/* The message should be NULL iff the reason is zero. */
gdb_assert ((result.reason == 0) == (result.message == nullptr));
return result;
}
/* Use this after a TRY/CATCH to throw the appropriate Scheme
exception if a GDB error occurred. */
@ -676,6 +705,7 @@ SCM
gdbscm_wrap (Function &&func, Args &&... args)
{
SCM result = SCM_BOOL_F;
gdbscm_gdb_exception exc {};
try
{
@ -683,9 +713,11 @@ gdbscm_wrap (Function &&func, Args &&... args)
}
catch (const gdb_exception &except)
{
GDBSCM_HANDLE_GDB_EXCEPTION (except);
exc = unpack (except);
}
GDBSCM_HANDLE_GDB_EXCEPTION (exc);
if (gdbscm_is_exception (result))
gdbscm_throw (result);