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authorAndrew Burgess <andrew.burgess@embecosm.com>2016-05-24 16:17:52 +0100
committerAndrew Burgess <andrew.burgess@embecosm.com>2016-05-27 13:06:25 +0100
commitac775bf4d35b7a2d5715e0ccf3d648d4670213fd (patch)
tree2a194c3e19f7e27d8fd9fb9ae6a3c130f9eb0dca /gdb/eval.c
parent9d07ebe108f4e11508e350eaf2ba10d7480636fa (diff)
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gdb: Forward VALUE_LVAL when avoiding side effects for STRUCTOP_PTR
Assume that we have a C program like this: struct foo_type { int var; } foo; struct foo_type *foo_ptr = &foo; int main () { return foo_ptr->var; } Then GDB should be able to evaluate the following, however, it currently does not: (gdb) start ... (gdb) whatis &(foo_ptr->var) Attempt to take address of value not located in memory. The problem is that in EVAL_AVOID_SIDE_EFFECTS mode, eval.c:evaluate_subexp_standard always returns a not_lval value as the result for a STRUCTOP_PTR operation. As a consequence, the rest of the code believes that one cannot take the address of the returned value. This patch fixes STRUCTOP_PTR handling so that the VALUE_LVAL attribute for the returned value is properly initialized. After this change, the above session becomes: (gdb) start ... (gdb) whatis &(foo_ptr->var) type = int * This commit is largely the same as commit 2520f728b710 (Forward VALUE_LVAL when avoiding side effects for STRUCTOP_STRUCT) but applied to STRUCTOP_PTR rather than STRUCTOP_STRUCT. Both of these commits are building on top of commit ac1ca910d74d (Fixes for PR exp/15364). gdb/ChangeLog: * eval.c (evaluate_subexp_standard): If EVAL_AVOID_SIDE_EFFECTS mode, forward the VALUE_LVAL attribute to the returned value in the STRUCTOP_PTR case. gdb/testsuite/ChangeLog: * gdb.base/whatis.c: Extend the test case. * gdb.base/whatis.exp: Add additional tests.
Diffstat (limited to 'gdb/eval.c')
-rw-r--r--gdb/eval.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/gdb/eval.c b/gdb/eval.c
index 3f8ca66..de1c663 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1917,7 +1917,7 @@ evaluate_subexp_standard (struct type *expect_type,
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);
+ arg3 = value_zero (value_type (arg3), VALUE_LVAL (arg3));
return arg3;
case STRUCTOP_MEMBER: