[03/03] Make breakpoint_address_match gdbarch_addr_bit-aware

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

this is a re-post of:
	[patch 03/15] PIE: breakpoint_address_match gdbarch_addr_bit workaround
	http://sourceware.org/ml/gdb-patches/2009-11/msg00170.html

I went the more correct way of making breakpoint_address_match dependent just
on address_space without requiring new gdbarch parameter(s); which may be IMO
even removed in the future according to [00/03].

Regression tested with [01/03] and [02/03] on
{x86_64,x86_64-m32,i686}-fedora12-linux-gnu.


Thanks,
Jan


2010-01-10  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* breakpoint.c (breakpoint_address_match): New variables addr1_bit,
	addr2_bit, addr1_mask and addr2_mask, initialize them.  New assertions
	on aspace1 and aspace2.  Mask addresses by ADDR1_MASK and ADDR2_MASK.
	* defs.h (CORE_ADDR): Extend the comment.

--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -4715,9 +4715,23 @@ static int
 breakpoint_address_match (struct address_space *aspace1, CORE_ADDR addr1,
 			  struct address_space *aspace2, CORE_ADDR addr2)
 {
+  int addr1_bit, addr2_bit;
+  CORE_ADDR addr1_mask = CORE_ADDR_MAX;
+  CORE_ADDR addr2_mask = CORE_ADDR_MAX;
+
+  gdb_assert (aspace1 != NULL);
+  gdb_assert (aspace2 != NULL);
+
+  addr1_bit = gdbarch_addr_bit (address_space_gdbarch (aspace1));
+  if (addr1_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
+    addr1_mask = ((CORE_ADDR) 1 << addr1_bit) - 1;
+  addr2_bit = gdbarch_addr_bit (address_space_gdbarch (aspace2));
+  if (addr2_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
+    addr2_mask = ((CORE_ADDR) 1 << addr2_bit) - 1;
+
   return ((gdbarch_has_global_breakpoints (target_gdbarch)
 	   || aspace1 == aspace2)
-	  && addr1 == addr2);
+	  && (addr1 & addr1_mask) == (addr2 & addr2_mask));
 }
 
 /* Assuming LOC1 and LOC2's types' have meaningful target addresses
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -98,7 +98,17 @@
 /* A byte from the program being debugged.  */
 typedef bfd_byte gdb_byte;
 
-/* An address in the program being debugged.  Host byte order.  */
+/* An address in the program being debugged.  Host byte order.
+
+   Its width is the maximum width of all the supported targets.  That means
+   32-bit target will run on such GDB using 64-bit CORE_ADDR cluttering the
+   bits 32...63 with random data from internal GDB calculations.  GDB currently
+   in general truncates the address width only when it is being presented/used
+   externally (such as by the paddress function).
+
+   FIXME: This is still not right as any GDB internal comparisons (such as >=)
+   of CORE_ADDR do not use the properly truncated width.  */
+
 typedef bfd_vma CORE_ADDR;
 
 /* The largest CORE_ADDR value.  */