2003-10-24 Andrew Cagney <cagney@redhat.com>

	* osabi.c (gdbarch_init_osabi): Add comment on 32-bit vs 64-bit.
	(can_run_code_for): Use the OO term "singleton".

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9d4e324f1c68a130448b164b147a8add9d63080c..176863bfcdb0df5c1a050a065c09b0c628c71dfe 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2003-10-24  Andrew Cagney  <cagney@redhat.com>
+
+       * osabi.c (gdbarch_init_osabi): Add comment on 32-bit vs 64-bit.
+       (can_run_code_for): Use the OO term "singleton".
+
 2003-10-23  Andrew Cagney  <cagney@redhat.com>
 
        * Makefile.in (stack.o): Add $(regcache_h).

diff --git a/gdb/osabi.c b/gdb/osabi.c
index e7774b7c3bf2bb47365f83fcfe45999af8cff029..fc712a61ffc6888b0d7f9de1aaa3a74933bdaafd 100644 (file)
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -295,9 +295,9 @@ can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
      written for B, but B can't run code written for A, then it'll
      return A.
 
-     struct bfd_arch_info objects are atoms: that is, there's supposed
-     to be exactly one instance for a given machine.  So you can tell
-     whether two are equivalent by comparing pointers.  */
+     struct bfd_arch_info objects are singletons: that is, there's
+     supposed to be exactly one instance for a given machine.  So you
+     can tell whether two are equivalent by comparing pointers.  */
   return (a == b || a->compatible (a, b) == a);
 }
 
@@ -333,6 +333,14 @@ gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
         type that is compatible with the desired machine type.  Right
         now we simply return the first match, which is fine for now.
         However, we might want to do something smarter in the future.  */
+      /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
+         is implemented using BFD's compatible method (a->compatible
+         (b) == a -- the lowest common denominator between a and b is
+         a).  That method's definition of compatible may not be as you
+         expect.  For instance, while "amd64 can run code for i386"
+         (or more generally "64-bit ISA can run code for the 32-bit
+         ISA").  Fortunatly, BFD doesn't normally consider 32-bit and
+         64-bit "compatible" so won't get a match.  */
       if (can_run_code_for (arch_info, handler->arch_info))
        {
          (*handler->init_osabi) (info, gdbarch);