[RFC] Unexpected automatic language switch - get_frame_language()
Wed Dec 10 17:42:00 GMT 2003
> >2003-12-09 J. Brobecker <email@example.com>
> > * frame.c (select_frame): Get the current frame PC using
> > get_frame_address_in_block() instead of get_frame_pc().
> > * stack.c (get_frame_language): Likewise.
> >Tested on x86-linux, with no regression.
> >OK to apply?
> Yes, but just add a comment at each point reminding us why the PC is
> wrong before committing.
Thanks. Here is the patch that I ended up committing. Let me know if
somebody would like the comments to be worded differently.
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RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.152
diff -u -p -r1.152 frame.c
--- frame.c 23 Nov 2003 21:49:12 -0000 1.152
+++ frame.c 10 Dec 2003 17:21:46 -0000
@@ -917,7 +917,13 @@ select_frame (struct frame_info *fi)
source language of this frame, and switch to it if desired. */
- s = find_pc_symtab (get_frame_pc (fi));
+ /* We retrieve the frame's symtab by using the frame PC. However
+ we cannot use the frame pc as is, because it usually points to
+ the instruction following the "call", which is sometimes the
+ first instruction of another function. So we rely on
+ get_frame_address_in_block() which provides us with a PC which
+ is guaranteed to be inside the frame's code block. */
+ s = find_pc_symtab (get_frame_address_in_block (fi));
&& s->language != current_language->la_language
&& s->language != language_unknown
RCS file: /cvs/src/src/gdb/stack.c,v
retrieving revision 1.97
diff -u -p -r1.97 stack.c
--- stack.c 23 Nov 2003 20:41:17 -0000 1.97
+++ stack.c 10 Dec 2003 17:21:47 -0000
@@ -2036,7 +2036,14 @@ get_frame_language (void)
- s = find_pc_symtab (get_frame_pc (deprecated_selected_frame));
+ /* We determine the current frame language by looking up its
+ associated symtab. To retrieve this symtab, we use the frame PC.
+ However we cannot use the frame pc as is, because it usually points
+ to the instruction following the "call", which is sometimes the first
+ instruction of another function. So we rely on
+ get_frame_address_in_block(), it provides us with a PC which is
+ guaranteed to be inside the frame's code block. */
+ s = find_pc_symtab (get_frame_address_in_block (deprecated_selected_frame));
flang = s->language;
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