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[PATCH 03/10] vla: enable sizeof operator to work with variable length arrays
- From: Sanimir Agovic <sanimir dot agovic at intel dot com>
- To: gdb-patches at sourceware dot org
- Date: Mon, 21 Oct 2013 16:40:17 +0200
- Subject: [PATCH 03/10] vla: enable sizeof operator to work with variable length arrays
- Authentication-results: sourceware.org; auth=none
- References: <1382366424-21010-1-git-send-email-sanimir dot agovic at intel dot com>
In C99 the sizeof operator computes the size of a variable length array
at runtime (6.5.3.4 The sizeof operator). This patch reflects the semantic
change in the debugger.
We now are able to get the size of a vla:
1| void foo (size_t n) {
2| int vla[n];
3| }
(gdb) p sizeof(vla)
yields N.
2013-10-18 Sanimir Agovic <sanimir.agovic@intel.com>
Keven Boell <keven.boell@intel.com>
* eval.c (evaluate_subexp_for_sizeof): If the type passed to sizeof is
dynamic evaluate the argument to compute the length.
* gdbtypes.c (is_dynamic_type): Make extern.
* gdbtypes.c (is_dynamic_type): Make extern.
Change-Id: I490f695f7a164be5f1f824fe3ba33f805d1ab689
---
gdb/eval.c | 8 +++++++-
gdb/gdbtypes.c | 2 +-
gdb/gdbtypes.h | 2 ++
3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/gdb/eval.c b/gdb/eval.c
index e83bfdf..9e4afa3 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -3041,8 +3041,14 @@ evaluate_subexp_for_sizeof (struct expression *exp, int *pos)
return value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type));
case OP_VAR_VALUE:
- (*pos) += 4;
type = check_typedef (SYMBOL_TYPE (exp->elts[pc + 2].symbol));
+ if (is_dynamic_type (type))
+ {
+ val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_NORMAL);
+ type = value_type (val);
+ }
+ else
+ (*pos) += 4;
return
value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type));
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index c0f375d..9774a4b 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1624,7 +1624,7 @@ resolve_dynamic_prop (const struct dwarf2_prop *prop, CORE_ADDR address,
/* Predicates if the type has dynamic values, which are not resolved yet. */
-static int
+int
is_dynamic_type (const struct type *type)
{
if (type == NULL)
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 96e0ed7..1252fd1 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -1580,6 +1580,8 @@ extern struct type *lookup_unsigned_typename (const struct language_defn *,
extern struct type *lookup_signed_typename (const struct language_defn *,
struct gdbarch *, const char *);
+extern int is_dynamic_type (const struct type *type);
+
extern struct type *resolve_dynamic_type (struct type *, CORE_ADDR);
extern struct type *check_typedef (struct type *);
--
1.7.0.7