Patch to __throw et al
Jason Merrill
jason@cygnus.com
Tue Mar 30 14:11:00 GMT 1999
We were failing to clean up the args space when returning to an exception
handler. This fixes that and tidies up the code a bit.
Tue Mar 30 13:19:36 1999 Jason Merrill <jason@yorick.cygnus.com>
* libgcc2.c (throw_helper): Just return the SP offset, rather than
a whole udata. Include args_size in the offset.
(__throw, __rethrow): Adjust.
Index: libgcc2.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/libgcc2.c,v
retrieving revision 1.62
diff -c -p -r1.62 libgcc2.c
*** libgcc2.c 1999/03/24 00:51:16 1.62
--- libgcc2.c 1999/03/30 22:09:46
*************** __unwinding_cleanup ()
*** 3692,3707 ****
for a dummy call to a routine __unwinding_cleanup() when there are nothing
but cleanups remaining. This allows a debugger to examine the state
at which the throw was executed, before any cleanups, rather than
! at the terminate point after the stack has been unwound. */
static void *
! throw_helper (eh, pc, my_udata, udata_p)
struct eh_context *eh;
void *pc;
frame_state *my_udata;
! frame_state **udata_p;
{
! frame_state *udata = *udata_p;
frame_state ustruct;
frame_state *sub_udata = &ustruct;
void *saved_pc = pc;
--- 3692,3712 ----
for a dummy call to a routine __unwinding_cleanup() when there are nothing
but cleanups remaining. This allows a debugger to examine the state
at which the throw was executed, before any cleanups, rather than
! at the terminate point after the stack has been unwound.
+ EH is the current eh_context structure.
+ PC is the address of the call to __throw.
+ MY_UDATA is the unwind information for __throw.
+ OFFSET_P is where we return the SP adjustment offset. */
+
static void *
! throw_helper (eh, pc, my_udata, offset_p)
struct eh_context *eh;
void *pc;
frame_state *my_udata;
! long *offset_p;
{
! frame_state ustruct2, *udata = &ustruct2;
frame_state ustruct;
frame_state *sub_udata = &ustruct;
void *saved_pc = pc;
*************** throw_helper (eh, pc, my_udata, udata_p)
*** 3714,3725 ****
--- 3719,3733 ----
int only_cleanup = 0;
int rethrow = 0;
int saved_state = 0;
+ long args_size;
__eh_info *eh_info = (__eh_info *)eh->info;
/* Do we find a handler based on a re-throw PC? */
if (eh->table_index != (void *) 0)
rethrow = 1;
+ memcpy (udata, my_udata, sizeof (*udata));
+
handler = (void *) 0;
for (;;)
{
*************** throw_helper (eh, pc, my_udata, udata_p)
*** 3795,3800 ****
--- 3803,3810 ----
eh->handler_label = handler;
+ args_size = udata->args_size;
+
if (pc == saved_pc)
/* We found a handler in the throw context, no need to unwind. */
udata = my_udata;
*************** throw_helper (eh, pc, my_udata, udata_p)
*** 3847,3853 ****
}
/* udata now refers to the frame called by the handler frame. */
! *udata_p = udata;
return handler;
}
--- 3857,3873 ----
}
/* udata now refers to the frame called by the handler frame. */
! /* We adjust SP by the difference between __throw's CFA and the CFA for
! the frame called by the handler frame, because those CFAs correspond
! to the SP values at the two call sites. We need to further adjust by
! the args_size of the handler frame itself to get the handler frame's
! SP from before the args were pushed for that call. */
! #ifdef STACK_GROWS_DOWNWARD
! *offset_p = udata->cfa - my_udata->cfa + args_size;
! #else
! *offset_p = my_udata->cfa - udata->cfa - args_size;
! #endif
!
return handler;
}
*************** __throw ()
*** 3867,3874 ****
{
struct eh_context *eh = (*get_eh_context) ();
void *pc, *handler;
! frame_state ustruct;
! frame_state *udata = &ustruct;
frame_state my_ustruct, *my_udata = &my_ustruct;
/* This is required for C++ semantics. We must call terminate if we
--- 3887,3896 ----
{
struct eh_context *eh = (*get_eh_context) ();
void *pc, *handler;
! long offset;
!
! /* XXX maybe make my_ustruct static so we don't have to look it up for
! each throw. */
frame_state my_ustruct, *my_udata = &my_ustruct;
/* This is required for C++ semantics. We must call terminate if we
*************** __throw ()
*** 3879,3892 ****
/* Start at our stack frame. */
label:
! udata = __frame_state_for (&&label, udata);
! if (! udata)
__terminate ();
/* We need to get the value from the CFA register. */
! udata->cfa = __builtin_dwarf_cfa ();
!
! memcpy (my_udata, udata, sizeof (*udata));
/* Do any necessary initialization to access arbitrary stack frames.
On the SPARC, this means flushing the register windows. */
--- 3901,3912 ----
/* Start at our stack frame. */
label:
! my_udata = __frame_state_for (&&label, my_udata);
! if (! my_udata)
__terminate ();
/* We need to get the value from the CFA register. */
! my_udata->cfa = __builtin_dwarf_cfa ();
/* Do any necessary initialization to access arbitrary stack frames.
On the SPARC, this means flushing the register windows. */
*************** label:
*** 3895,3911 ****
/* Now reset pc to the right throw point. */
pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
! handler = throw_helper (eh, pc, my_udata, &udata);
/* Now go! */
! __builtin_eh_return ((void *)eh,
! #ifdef STACK_GROWS_DOWNWARD
! udata->cfa - my_udata->cfa,
! #else
! my_udata->cfa - udata->cfa,
! #endif
! handler);
/* Epilogue: restore the handler frame's register values and return
to the stub. */
--- 3915,3925 ----
/* Now reset pc to the right throw point. */
pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
! handler = throw_helper (eh, pc, my_udata, &offset);
/* Now go! */
! __builtin_eh_return ((void *)eh, offset, handler);
/* Epilogue: restore the handler frame's register values and return
to the stub. */
*************** __rethrow (index)
*** 3919,3926 ****
{
struct eh_context *eh = (*get_eh_context) ();
void *pc, *handler;
! frame_state ustruct;
! frame_state *udata = &ustruct;
frame_state my_ustruct, *my_udata = &my_ustruct;
/* This is required for C++ semantics. We must call terminate if we
--- 3933,3942 ----
{
struct eh_context *eh = (*get_eh_context) ();
void *pc, *handler;
! long offset;
!
! /* XXX maybe make my_ustruct static so we don't have to look it up for
! each throw. */
frame_state my_ustruct, *my_udata = &my_ustruct;
/* This is required for C++ semantics. We must call terminate if we
*************** __rethrow (index)
*** 3936,3950 ****
/* Start at our stack frame. */
label:
! udata = __frame_state_for (&&label, udata);
! if (! udata)
__terminate ();
/* We need to get the value from the CFA register. */
! udata->cfa = __builtin_dwarf_cfa ();
- memcpy (my_udata, udata, sizeof (*udata));
-
/* Do any necessary initialization to access arbitrary stack frames.
On the SPARC, this means flushing the register windows. */
__builtin_unwind_init ();
--- 3952,3964 ----
/* Start at our stack frame. */
label:
! my_udata = __frame_state_for (&&label, my_udata);
! if (! my_udata)
__terminate ();
/* We need to get the value from the CFA register. */
! my_udata->cfa = __builtin_dwarf_cfa ();
/* Do any necessary initialization to access arbitrary stack frames.
On the SPARC, this means flushing the register windows. */
__builtin_unwind_init ();
*************** label:
*** 3952,3968 ****
/* Now reset pc to the right throw point. */
pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
! handler = throw_helper (eh, pc, my_udata, &udata);
/* Now go! */
! __builtin_eh_return ((void *)eh,
! #ifdef STACK_GROWS_DOWNWARD
! udata->cfa - my_udata->cfa,
! #else
! my_udata->cfa - udata->cfa,
! #endif
! handler);
/* Epilogue: restore the handler frame's register values and return
to the stub. */
--- 3966,3976 ----
/* Now reset pc to the right throw point. */
pc = __builtin_extract_return_addr (__builtin_return_address (0)) - 1;
! handler = throw_helper (eh, pc, my_udata, &offset);
/* Now go! */
! __builtin_eh_return ((void *)eh, offset, handler);
/* Epilogue: restore the handler frame's register values and return
to the stub. */
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