[03/19] set_longjmp_breakpoint

[03/19] set_longjmp_breakpoint

[Ulrich Weigand]

Hello,

set_longjmp_breakpoint uses
  if (gdbarch_get_longjmp_target_p (current_gdbarch))
to determine whether to install a longjmp breakpoint.

This patch uses the objfile architecture of the file defining the
longjmp entry point to find the gdbarch_get_longjmp_target routine.

As a side effect, if multiple objfiles provide longjmp, *all*
instances will now get the breakpoint installed -- this may actually
be useful in some circumstances (e.g. multiple SPE images in a Cell/B.E.
application).

Bye,
Ulrich

ChangeLog:

	* breakpoint.c (create_longjmp_breakpoint): Add OBJFILE parameter.
	Only create breakpoint in given objfile.
	(set_longjmp_breakpoint): Loop over all objfiles, set longjmp
	breakpoints in each file.  Use objfile architecture instead of
	current_gdbarch.

Index: gdb-head/gdb/breakpoint.c
===================================================================
--- gdb-head.orig/gdb/breakpoint.c
+++ gdb-head/gdb/breakpoint.c
@@ -4423,11 +4423,11 @@ make_breakpoint_permanent (struct breakp
 }
 
 static void
-create_longjmp_breakpoint (char *func_name)
+create_longjmp_breakpoint (char *func_name, struct objfile *objfile)
 {
   struct minimal_symbol *m;
 
-  if ((m = lookup_minimal_symbol_text (func_name, NULL)) == NULL)
+  if ((m = lookup_minimal_symbol_text (func_name, objfile)) == NULL)
     return;
   set_momentary_breakpoint_at_pc (SYMBOL_VALUE_ADDRESS (m), bp_longjmp);
   update_global_location_list (1);
@@ -4440,12 +4440,17 @@ create_longjmp_breakpoint (char *func_na
 void
 set_longjmp_breakpoint (void)
 {
-  if (gdbarch_get_longjmp_target_p (current_gdbarch))
+  struct objfile *objfile;
+  ALL_OBJFILES (objfile)
     {
-      create_longjmp_breakpoint ("longjmp");
-      create_longjmp_breakpoint ("_longjmp");
-      create_longjmp_breakpoint ("siglongjmp");
-      create_longjmp_breakpoint ("_siglongjmp");
+      struct gdbarch *gdbarch = get_objfile_arch (objfile);
+      if (!gdbarch_get_longjmp_target_p (gdbarch))
+	continue;
+
+      create_longjmp_breakpoint ("longjmp", objfile);
+      create_longjmp_breakpoint ("_longjmp", objfile);
+      create_longjmp_breakpoint ("siglongjmp", objfile);
+      create_longjmp_breakpoint ("_siglongjmp", objfile);
     }
 }
 
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com

Re: [03/19] set_longjmp_breakpoint

[Tom Tromey]

>>>>> "Ulrich" == Ulrich Weigand <uweigand@de.ibm.com> writes:

Ulrich> As a side effect, if multiple objfiles provide longjmp, *all*
Ulrich> instances will now get the breakpoint installed -- this may actually
Ulrich> be useful in some circumstances (e.g. multiple SPE images in a Cell/B.E.
Ulrich> application).

This seems reasonable to me, but I am somewhat concerned about
performance.  I think this patch means that every "next" will involve
looking up four symbols in every objfile.

Do you know how big an effect this has?  Or maybe Paul could try it
on his famous kilo-.so program.

I suppose if that is very slow we could add some kind of per-inferior
cache.. ?

Tom