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RFC: fix PR 15364
- From: Tom Tromey <tromey at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Fri, 12 Apr 2013 12:54:43 -0600
- Subject: RFC: fix PR 15364
My earlier fix for PR 9197 introduced a regression.
You can see it clearly here:
(gdb) p s2
$1 = (struct s *) 0x0
(gdb) p s2 && s2->x == 0
Cannot access memory at address 0x0
The exception in this case is thrown by binop_promote, but I think that
a lot of code expects EVAL_AVOID_SIDE_EFFECTS to return a not_lval
value, so I fixed the problem by changing the various spots I touched
for 9197 to do this.
Built and regtested on x86-64 Fedora 18.
New test case included.
Tom
2013-04-12 Tom Tromey <tromey@redhat.com>
PR exp/15364:
* eval.c (evaluate_subexp_standard) <STRUCTOP_STRUCT,
STRUCTOP_PTR>: Return a not_lval value for
EVAL_AVOID_SIDE_EFFECTS.
* opencl-lang.c (evaluate_subexp_opencl): Return a not_lval value
for EVAL_AVOID_SIDE_EFFECTS.
2013-04-12 Tom Tromey <tromey@redhat.com>
* gdb.base/exprs.exp (test_expr): Add regression test.
* gdb.base/exprs.c (null_t_struct): New global.
diff --git a/gdb/eval.c b/gdb/eval.c
index a91ba22..eee457e 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1847,9 +1847,11 @@ evaluate_subexp_standard (struct type *expect_type,
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
if (noside == EVAL_SKIP)
goto nosideret;
- /* Also handle EVAL_AVOID_SIDE_EFFECTS. */
- return value_struct_elt (&arg1, NULL, &exp->elts[pc + 2].string,
+ arg3 = value_struct_elt (&arg1, NULL, &exp->elts[pc + 2].string,
NULL, "structure");
+ if (noside == EVAL_AVOID_SIDE_EFFECTS)
+ arg3 = value_zero (value_type (arg3), not_lval);
+ return arg3;
case STRUCTOP_PTR:
tem = longest_to_int (exp->elts[pc + 1].longconst);
@@ -1899,9 +1901,11 @@ evaluate_subexp_standard (struct type *expect_type,
}
}
- /* Also handle EVAL_AVOID_SIDE_EFFECTS. */
- return value_struct_elt (&arg1, NULL, &exp->elts[pc + 2].string,
+ arg3 = value_struct_elt (&arg1, NULL, &exp->elts[pc + 2].string,
NULL, "structure pointer");
+ if (noside == EVAL_AVOID_SIDE_EFFECTS)
+ arg3 = value_zero (value_type (arg3), not_lval);
+ return arg3;
case STRUCTOP_MEMBER:
case STRUCTOP_MPTR:
diff --git a/gdb/opencl-lang.c b/gdb/opencl-lang.c
index d7e66c4..4720e2b 100644
--- a/gdb/opencl-lang.c
+++ b/gdb/opencl-lang.c
@@ -1035,10 +1035,13 @@ Cannot perform conditional operation on vectors with different sizes"));
}
else
{
- /* Also handle EVAL_AVOID_SIDE_EFFECTS. */
- return value_struct_elt (&arg1, NULL,
- &exp->elts[pc + 2].string, NULL,
- "structure");
+ struct value *v = value_struct_elt (&arg1, NULL,
+ &exp->elts[pc + 2].string, NULL,
+ "structure");
+
+ if (noside == EVAL_AVOID_SIDE_EFFECTS)
+ v = value_zero (value_type (v), not_lval);
+ return v;
}
}
default:
diff --git a/gdb/testsuite/gdb.base/exprs.c b/gdb/testsuite/gdb.base/exprs.c
index 90c0f25..e1ad182 100644
--- a/gdb/testsuite/gdb.base/exprs.c
+++ b/gdb/testsuite/gdb.base/exprs.c
@@ -185,6 +185,7 @@ union tu_link {
enum colors {red, green, blue} color;
enum cars {chevy, ford, porsche} clunker;
+struct t_struct *null_t_struct;
void dummy()
{
diff --git a/gdb/testsuite/gdb.base/exprs.exp b/gdb/testsuite/gdb.base/exprs.exp
index fa3cdb4..d2e23c9 100644
--- a/gdb/testsuite/gdb.base/exprs.exp
+++ b/gdb/testsuite/gdb.base/exprs.exp
@@ -273,3 +273,7 @@ gdb_test "print {short} v_short_array" "$decimal = 42"
# Regression tests for cast to void.
gdb_test "print (void) v_int_pointer" " = void"
gdb_test "print & (void) v_char" "value not located in memory."
+
+# Regression test for "&&".
+gdb_test "print null_t_struct && null_t_struct->v_int_member == 0" \
+ " = 0"