[binutils-gdb] [Cell/B.E.] Fix regression due to gdbarch_significant_addr_bit

[Ulrich Weigand <uweigand at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=396d3980f518cfc9a936e3fb8138b0492399525a

commit 396d3980f518cfc9a936e3fb8138b0492399525a
Author: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Date:   Wed Dec 20 13:59:14 2017 +0100

    [Cell/B.E.] Fix regression due to gdbarch_significant_addr_bit
    
    On Cell/B.E. multi-architecture debugging we use a "merged" address space
    that encodes both the main PowerPC address space and the local store address
    spaces of all active SPUs.  This will always occupy 64 bits.
    
    However, gdbarch_addr_bit is set to 32 on SPU, and may be set to 32 as well
    on PowerPC.  Since the new gdbarch_significant_addr_bit defaults to the
    value of gdbarch_addr_bit, this means addresses may be improperly truncated.
    
    Work around this problem by explicitly setting gdbarch_significant_addr_bit
    to 64 both for the SPU target and also for PowerPC target that support
    Cell/B.E. execution.
    
    gdb/ChangeLog:
    2017-12-20  Ulrich Weigand  <uweigand@de.ibm.com>
    
    	* spu-tdep.c (spu_gdbarch_init): Set set_gdbarch_significant_addr_bit
    	to 64 bits.
    	(ppc_linux_init_abi): Likewise, if Cell/B.E. is supported.

Diff:
---
 gdb/ChangeLog        | 6 ++++++
 gdb/ppc-linux-tdep.c | 4 ++++
 gdb/spu-tdep.c       | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f314e8e..dc6406a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-20  Ulrich Weigand  <uweigand@de.ibm.com>
+
+	* spu-tdep.c (spu_gdbarch_init): Set set_gdbarch_significant_addr_bit
+	to 64 bits.
+	(ppc_linux_init_abi): Likewise, if Cell/B.E. is supported.
+
 2017-12-18  Joel Brobecker  <brobecker@adacore.com>
 
 	* ada-lang.c (ada_to_fixed_type_1): Rethrow errors with
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index 0e43a64..5120490 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1809,6 +1809,10 @@ ppc_linux_init_abi (struct gdbarch_info info,
 
       /* Cell/B.E. cross-architecture unwinder support.  */
       frame_unwind_prepend_unwinder (gdbarch, &ppu2spu_unwind);
+
+      /* We need to support more than "addr_bit" significant address bits
+         in order to support SPUADDR_ADDR encoded values.  */
+      set_gdbarch_significant_addr_bit (gdbarch, 64);
     }
 
   set_gdbarch_displaced_step_location (gdbarch,
diff --git a/gdb/spu-tdep.c b/gdb/spu-tdep.c
index fb9a5d8..dda3011 100644
--- a/gdb/spu-tdep.c
+++ b/gdb/spu-tdep.c
@@ -2720,6 +2720,9 @@ spu_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_address_class_name_to_type_flags
     (gdbarch, spu_address_class_name_to_type_flags);
 
+  /* We need to support more than "addr_bit" significant address bits
+     in order to support SPUADDR_ADDR encoded values.  */
+  set_gdbarch_significant_addr_bit (gdbarch, 64);
 
   /* Inferior function calls.  */
   set_gdbarch_call_dummy_location (gdbarch, ON_STACK);