[PATCH] gdb: fix logic of find_comp_unit and set_comp_unit

[PATCH] gdb: fix logic of find_comp_unit and set_comp_unit

[Simon Marchi via Gdb-patches]

The logic in find_comp_unit and set_comp_unit is reversed.  When the BFD
requires relocation, we want to put the comp_unit structure in the
map where the comp_unit objects are not shared, that is the one indexed
by objfile.  If the BFD does not require relocation, then, we can share
a single comp_unit structure for all users of that BFD, so we want to
put it in the BFD-indexed map.  The comments on top of
dwarf2_frame_bfd_data and dwarf2_frame_objfile_data make that clear.

Fix it by swapping the two in find_comp_unit and set_comp_unit.

I don't have a test for this, because I don't see how to write one in a
reasonable amount of time.

gdb/ChangeLog:

	PR gdb/26876
	* dwarf2/frame.c (find_comp_unit, set_comp_unit): Reverse use of
	dwarf2_frame_bfd_data and dwarf2_frame_objfile_data.

Change-Id: I80c1ee7ad8425fa4947de65b170973d05f5a52ec
---
 gdb/dwarf2/frame.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c
index a577a671f242..7df3ccfe46a7 100644
--- a/gdb/dwarf2/frame.c
+++ b/gdb/dwarf2/frame.c
@@ -1640,8 +1640,9 @@ find_comp_unit (struct objfile *objfile)
 {
   bfd *abfd = objfile->obfd;
   if (gdb_bfd_requires_relocations (abfd))
-    return dwarf2_frame_bfd_data.get (abfd);
-  return dwarf2_frame_objfile_data.get (objfile);
+    return dwarf2_frame_objfile_data.get (objfile);
+
+  return dwarf2_frame_bfd_data.get (abfd);
 }
 
 /* Store the comp_unit on OBJFILE, or the corresponding BFD, as
@@ -1652,8 +1653,9 @@ set_comp_unit (struct objfile *objfile, struct comp_unit *unit)
 {
   bfd *abfd = objfile->obfd;
   if (gdb_bfd_requires_relocations (abfd))
-    return dwarf2_frame_bfd_data.set (abfd, unit);
-  return dwarf2_frame_objfile_data.set (objfile, unit);
+    return dwarf2_frame_objfile_data.set (objfile, unit);
+
+  return dwarf2_frame_bfd_data.set (abfd, unit);
 }
 
 /* Find the FDE for *PC.  Return a pointer to the FDE, and store the
-- 
2.29.2

Re: [PATCH] gdb: fix logic of find_comp_unit and set_comp_unit

[Tom Tromey]

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> 	PR gdb/26876
Simon> 	* dwarf2/frame.c (find_comp_unit, set_comp_unit): Reverse use of
Simon> 	dwarf2_frame_bfd_data and dwarf2_frame_objfile_data.

This looks good to me.  Thank you.

Tom

Re: [PATCH] gdb: fix logic of find_comp_unit and set_comp_unit

[Simon Marchi via Gdb-patches]

On 2020-12-03 3:42 p.m., Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Simon> 	PR gdb/26876
> Simon> 	* dwarf2/frame.c (find_comp_unit, set_comp_unit): Reverse use of
> Simon> 	dwarf2_frame_bfd_data and dwarf2_frame_objfile_data.
> 
> This looks good to me.  Thank you.
> 
> Tom
> 

Thanks, pushed!

Simon