[binutils-gdb] Fix latent bug in msp430-tdep.c

[Tom Tromey <tromey at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ef789dc484a35159ad825c98c4a2502f2097aed7

commit ef789dc484a35159ad825c98c4a2502f2097aed7
Author: Tom Tromey <tom@tromey.com>
Date:   Sat Apr 21 22:42:00 2018 -0600

    Fix latent bug in msp430-tdep.c
    
    -Wshadow=local found this latent bug.  msp430-tdep.c does:
    
        const gdb_byte *arg_bits;
        {
          /* Aggregates of any size are passed by reference.  */
          gdb_byte struct_addr[4];
    [...
          arg_bits = struct_addr;
        }
        ... use arg_bits
    
    Here, arg_bits can point to an object that's gone out of scope.
    
    The fix is to hoist the inner "struct_addr" buffer to an outer scope,
    and rename it to avoid shadowing.
    
    gdb/ChangeLog
    2018-10-04  Tom Tromey  <tom@tromey.com>
    
    	* msp430-tdep.c (msp430_push_dummy_call): Rename inner
    	"structs_addr" and hoist declaration.

Diff:
---
 gdb/ChangeLog     | 5 +++++
 gdb/msp430-tdep.c | 7 +++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c547ee9..9a8390b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2018-10-04  Tom Tromey  <tom@tromey.com>
 
+	* msp430-tdep.c (msp430_push_dummy_call): Rename inner
+	"structs_addr" and hoist declaration.
+
+2018-10-04  Tom Tromey  <tom@tromey.com>
+
 	* linux-tdep.c (linux_make_mappings_corefile_notes): Introduce new
 	variable "size".
 
diff --git a/gdb/msp430-tdep.c b/gdb/msp430-tdep.c
index b6e062a..427f58c 100644
--- a/gdb/msp430-tdep.c
+++ b/gdb/msp430-tdep.c
@@ -715,6 +715,7 @@ msp430_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	  ULONGEST arg_size = TYPE_LENGTH (arg_type);
 	  int offset;
 	  int current_arg_on_stack;
+	  gdb_byte struct_addr_buf[4];
 
 	  current_arg_on_stack = 0;
 
@@ -722,11 +723,9 @@ msp430_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	      || TYPE_CODE (arg_type) == TYPE_CODE_UNION)
 	    {
 	      /* Aggregates of any size are passed by reference.  */
-	      gdb_byte struct_addr[4];
-
-	      store_unsigned_integer (struct_addr, 4, byte_order,
+	      store_unsigned_integer (struct_addr_buf, 4, byte_order,
 				      value_address (arg));
-	      arg_bits = struct_addr;
+	      arg_bits = struct_addr_buf;
 	      arg_size = (code_model == MSP_LARGE_CODE_MODEL) ? 4 : 2;
 	    }
 	  else