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[rfa:dwarf2] Use frame_unwind_address_in_block
- From: Andrew Cagney <ac131313 at redhat dot com>
- To: gdb-patches at sources dot redhat dot com
- Date: Wed, 16 Jul 2003 19:21:39 -0400
- Subject: [rfa:dwarf2] Use frame_unwind_address_in_block
Hello,
This, finally, is the tweak to the dwarf2-unwind code, to use the
frame's address-in-block, instead of the frame's PC to select the CFI
info. Two test cases stop failing:
1gdb.base/corefile.exp: backtrace in corefile.exp FAIL PASS
2gdb.base/gdb1250.exp: backtrace from abort KFAIL PASS
Ok for the mainline?
Ok to pull something equivalent into 6.0 branch?
Andrew
2003-07-16 Andrew Cagney <cagney@redhat.com>
* dwarf2-frame.c (dwarf2_frame_sniffer): Use
frame_unwind_address_in_block, instead of frame_pc_unwind.
(dwarf2_frame_cache): Ditto.
Index: dwarf2-frame.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2-frame.c,v
retrieving revision 1.9
diff -u -r1.9 dwarf2-frame.c
--- dwarf2-frame.c 16 Jul 2003 22:29:13 -0000 1.9
+++ dwarf2-frame.c 16 Jul 2003 23:13:29 -0000
@@ -491,15 +491,12 @@
done for "normal" frames and not for resume-type frames (signal
handlers, sentinel frames, dummy frames).
- We don't do what GCC's does here (yet). It's not clear how
- reliable the method is. There's also a problem with finding the
- right FDE; see the comment in dwarf_frame_p. If dwarf_frame_p
- selected this frame unwinder because it found the FDE for the
- next function, using the adjusted return address might not yield
- a FDE at all. The problem isn't specific to DWARF CFI; other
- unwinders loose in similar ways. Therefore it's probably
- acceptable to leave things slightly broken for now. */
- fs->pc = frame_pc_unwind (next_frame);
+ frame_unwind_address_in_block does just this.
+
+ It's not clear how reliable the method is though - there is the
+ potential for the register state pre-call being different to that
+ on return. */
+ fs->pc = frame_unwind_address_in_block (next_frame);
/* Find the correct FDE. */
fde = dwarf2_frame_find_fde (&fs->pc);
@@ -710,15 +707,11 @@
const struct frame_unwind *
dwarf2_frame_sniffer (struct frame_info *next_frame)
{
- CORE_ADDR pc = frame_pc_unwind (next_frame);
- /* The way GDB works, this function can be called with PC just after
- the last instruction of the function we're supposed to return the
- unwind methods for. In that case we won't find the correct FDE;
- instead we find the FDE for the next function, or we won't find
- an FDE at all. There is a possible solution (see the comment in
- dwarf2_frame_cache), GDB doesn't pass us enough information to
- implement it. */
- if (dwarf2_frame_find_fde (&pc))
+ /* Grab an address that is guarenteed to reside somewhere within the
+ function. frame_pc_unwind(), for a no-return next function, can
+ end up returning something past the end of this function's body. */
+ CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame);
+ if (dwarf2_frame_find_fde (&block_addr))
return &dwarf2_frame_unwind;
return NULL;