Re: [PING]RE: [RFA] Fix maint translate command

[Pedro Alves <pedro at codesourcery dot com>]

On Wednesday 22 September 2010 19:59:03, Pedro Alves wrote:
> On Wednesday 22 September 2010 18:01:11, Joel Brobecker wrote:

> > I think that this is a useful comment to add to the macro.  And perhaps
> > explain that the purpose is to allow `break' to exit the ALL_OBJSECTIONS
> > (double-) loop.
> 
> I'll extend the current comment in that direction.

Done now.  Tested on x86_64-unknown-linux-gnu and applied.

-- 
Pedro Alves

2010-09-24  Pedro Alves  <pedro@codesourcery.com>

	* objfiles.h (ALL_OBJSECTIONS): Handle breaks in the inner loop.

---
 gdb/objfiles.h |   41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

Index: src/gdb/objfiles.h
===================================================================
--- src.orig/gdb/objfiles.h	2010-09-24 10:22:44.000000000 +0100
+++ src/gdb/objfiles.h	2010-09-24 11:32:44.000000000 +0100
@@ -611,9 +611,44 @@ extern int gdb_bfd_close_or_warn (struct
 #define ALL_OBJFILE_OSECTIONS(objfile, osect)	\
   for (osect = objfile->sections; osect < objfile->sections_end; osect++)
 
-#define ALL_OBJSECTIONS(objfile, osect)		\
-  ALL_OBJFILES (objfile)			\
-    ALL_OBJFILE_OSECTIONS (objfile, osect)
+/* Traverse all obj_sections in all objfiles in the current program
+   space.
+
+   Note that this detects a "break" in the inner loop, and exits
+   immediately from the outer loop as well, thus, client code doesn't
+   need to know that this is implemented with a double for.  The extra
+   hair is to make sure that a "break;" stops the outer loop iterating
+   as well, and both OBJFILE and OSECT are left unmodified:
+
+    - The outer loop learns about the inner loop's end condition, and
+      stops iterating if it detects the inner loop didn't reach its
+      end.  In other words, the outer loop keeps going only if the
+      inner loop reached its end cleanly [(osect) ==
+      (objfile)->sections_end].
+
+    - OSECT is initialized in the outer loop initialization
+      expressions, such as if the inner loop has reached its end, so
+      the check mentioned above succeeds the first time.
+
+    - The trick to not clearing OBJFILE on a "break;" is, in the outer
+      loop's loop expression, advance OBJFILE, but iff the inner loop
+      reached its end.  If not, there was a "break;", so leave OBJFILE
+      as is; the outer loop's conditional will break immediately as
+      well (as OSECT will be different from OBJFILE->sections_end).
+*/
+
+#define ALL_OBJSECTIONS(objfile, osect)					\
+  for ((objfile) = current_program_space->objfiles,			\
+	 (objfile) != NULL ? ((osect) = (objfile)->sections_end) : 0;	\
+       (objfile) != NULL						\
+	 && (osect) == (objfile)->sections_end;				\
+       ((osect) == (objfile)->sections_end				\
+	? ((objfile) = (objfile)->next,					\
+	   (objfile) != NULL ? (osect) = (objfile)->sections_end : 0)	\
+	: 0))								\
+    for ((osect) = (objfile)->sections;					\
+	 (osect) < (objfile)->sections_end;				\
+	 (osect)++)
 
 #define SECT_OFF_DATA(objfile) \
      ((objfile->sect_index_data == -1) \