Allow re-assigning to convenience variables

In Ada mode, re-assigning an array of a different size to a
convenience variable will cause an error:

    (gdb) set lang ada
    (gdb) set $v := "abc"
    (gdb) set $v := "abcd"
    cannot assign arrays of different length

However, this does not really make sense -- instead, it should always
be possible to overwrite a convenience variable.

This patch fixes this bug.

This was reviewed off-list by Joel.  I'm checking it in.

gdb/ChangeLog
2019-06-14  Tom Tromey  <tromey@adacore.com>

	* ada-lang.c (ada_evaluate_subexp) <case BINOP_ASSIGN>: Always
	allow assignment to an internalvar.

gdb/testsuite/ChangeLog
2019-06-14  Tom Tromey  <tromey@adacore.com>

	* gdb.ada/set_wstr.exp: Add reassignment test.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9fbfcfa..ee3377c 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2019-06-14  Tom Tromey  <tromey@adacore.com>
 
+       * ada-lang.c (ada_evaluate_subexp) <case BINOP_ASSIGN>: Always
+       allow assignment to an internalvar.
+
+2019-06-14  Tom Tromey  <tromey@adacore.com>
+
        * ada-lex.l: Allow "_" in attribute names.
 
 2019-06-14  Tom Tromey  <tromey@adacore.com>

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 1f0ada3..1b5f183 100644 (file)
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -10486,7 +10486,11 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
       arg2 = evaluate_subexp (type, exp, pos, noside);
       if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
         return arg1;
-      if (ada_is_fixed_point_type (value_type (arg1)))
+      if (VALUE_LVAL (arg1) == lval_internalvar)
+       {
+         /* Nothing.  */
+       }
+      else if (ada_is_fixed_point_type (value_type (arg1)))
         arg2 = cast_to_fixed (value_type (arg1), arg2);
       else if (ada_is_fixed_point_type (value_type (arg2)))
         error

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 9bfd570..8219486 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,9 @@
 2019-06-14  Tom Tromey  <tromey@adacore.com>
 
+       * gdb.ada/set_wstr.exp: Add reassignment test.
+
+2019-06-14  Tom Tromey  <tromey@adacore.com>
+
        * gdb.ada/formatted_ref.exp (test_p_x_addr): Check
        'unchecked_access and 'unrestricted_access as well.
 

diff --git a/gdb/testsuite/gdb.ada/set_wstr.exp b/gdb/testsuite/gdb.ada/set_wstr.exp
index 0c5c42c..ac70985 100644 (file)
--- a/gdb/testsuite/gdb.ada/set_wstr.exp
+++ b/gdb/testsuite/gdb.ada/set_wstr.exp
@@ -72,3 +72,8 @@ gdb_test "print rws" \
 
 gdb_test "set variable www := \"1#2#3#4#5#\"" \
          "cannot assign arrays of different length"
+
+# However, reassigning an array of a different length should work when
+# the LHS is a convenience variable.
+gdb_test_no_output "set variable \$str := \"1234\""
+gdb_test_no_output "set variable \$str := \"12345\""