* [PATCH] Allow calling of variadic C++ functions
[not found] <20231212161255.3597-1-ssbssa.ref@yahoo.de>
@ 2023-12-12 16:12 ` Hannes Domani
2023-12-12 20:23 ` Tom Tromey
0 siblings, 1 reply; 2+ messages in thread
From: Hannes Domani @ 2023-12-12 16:12 UTC (permalink / raw)
To: gdb-patches
Currently, it's not possible to call a variadic C++ function:
```
(gdb) print sum_vararg_int(1, 10)
Cannot resolve function sum_vararg_int to any overloaded instance
(gdb) print sum_vararg_int(2, 20, 30)
Cannot resolve function sum_vararg_int to any overloaded instance
```
It's because all additional arguments get the TOO_FEW_PARAMS_BADNESS
rank by rank_function, which disqualifies the function.
To fix this, I've created the new VARARG_BADNESS rank, which is
used only for additional arguments of variadic functions, allowing
them to be called:
```
(gdb) print sum_vararg_int(1, 10)
$1 = 10
(gdb) print sum_vararg_int(2, 20, 30)
$2 = 50
```
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28589
---
gdb/gdbtypes.c | 6 ++++--
gdb/gdbtypes.h | 3 ++-
gdb/testsuite/gdb.cp/call-c.cc | 16 ++++++++++++++++
gdb/testsuite/gdb.cp/call-c.exp | 5 +++++
gdb/valops.c | 10 ++++++++--
5 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 4c70c9b8ae6..6b9bc661680 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -65,6 +65,7 @@ const struct rank INTEGER_PROMOTION_BADNESS = {1,0};
const struct rank FLOAT_PROMOTION_BADNESS = {1,0};
const struct rank BASE_PTR_CONVERSION_BADNESS = {1,0};
const struct rank CV_CONVERSION_BADNESS = {1, 0};
+const struct rank VARARG_BADNESS = {1, 0};
const struct rank INTEGER_CONVERSION_BADNESS = {2,0};
const struct rank FLOAT_CONVERSION_BADNESS = {2,0};
const struct rank INT_FLOAT_CONVERSION_BADNESS = {2,0};
@@ -4038,7 +4039,8 @@ compare_badness (const badness_vector &a, const badness_vector &b)
badness_vector
rank_function (gdb::array_view<type *> parms,
- gdb::array_view<value *> args)
+ gdb::array_view<value *> args,
+ bool varargs)
{
/* add 1 for the length-match rank. */
badness_vector bv;
@@ -4064,7 +4066,7 @@ rank_function (gdb::array_view<type *> parms,
/* If more arguments than parameters, add dummy entries. */
for (size_t i = min_len; i < args.size (); i++)
- bv.push_back (TOO_FEW_PARAMS_BADNESS);
+ bv.push_back (varargs ? VARARG_BADNESS : TOO_FEW_PARAMS_BADNESS);
return bv;
}
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index eca92196364..4b563e79546 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -2735,7 +2735,8 @@ extern int compare_badness (const badness_vector &,
const badness_vector &);
extern badness_vector rank_function (gdb::array_view<type *> parms,
- gdb::array_view<value *> args);
+ gdb::array_view<value *> args,
+ bool varargs = false);
extern struct rank rank_one_type (struct type *, struct type *,
struct value *);
diff --git a/gdb/testsuite/gdb.cp/call-c.cc b/gdb/testsuite/gdb.cp/call-c.cc
index 4362bbf2143..bcf08883788 100644
--- a/gdb/testsuite/gdb.cp/call-c.cc
+++ b/gdb/testsuite/gdb.cp/call-c.cc
@@ -15,6 +15,8 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
+#include <stdarg.h>
+
int func(int x)
{
return x;
@@ -33,6 +35,19 @@ extern "C" {
int foo(int);
}
+int sum_vararg_int (int count, ...)
+{
+ va_list va;
+ int sum = 0;
+
+ va_start (va, count);
+ for (int i = 0; i < count; i++)
+ sum += va_arg (va, int);
+ va_end (va);
+
+ return sum;
+}
+
int main()
{
Foo f;
@@ -41,5 +56,6 @@ int main()
FooHandle handle = pf;
rf->func(); /* set breakpoint here */
foo(0);
+ sum_vararg_int (1, 5);
return func(0);
}
diff --git a/gdb/testsuite/gdb.cp/call-c.exp b/gdb/testsuite/gdb.cp/call-c.exp
index b20bc8698ca..7cb9eef34c7 100644
--- a/gdb/testsuite/gdb.cp/call-c.exp
+++ b/gdb/testsuite/gdb.cp/call-c.exp
@@ -38,5 +38,10 @@ gdb_test "print foo(1)" "\\\$$decimal = 1"
gdb_test "continue" ".*breakpoint here.*" "continue to bp"
gdb_test "print rf->func()" "\\\$$decimal = 1"
+gdb_test "print sum_vararg_int(0)" "0"
+gdb_test "print sum_vararg_int(1, 10)" "10"
+gdb_test "print sum_vararg_int(2, 20, 30)" "50"
+gdb_test "print sum_vararg_int(5, 20, 30, 40, 50, 60)" "200"
+
# Regression test for method call via a typedef.
gdb_test "print handle->func()" "\\\$$decimal = 1"
diff --git a/gdb/valops.c b/gdb/valops.c
index 49ea1fd7676..a15c92bd222 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -3226,6 +3226,7 @@ find_oload_champ (gdb::array_view<value *> args,
{
int jj;
int static_offset = 0;
+ bool varargs = false;
std::vector<type *> parm_types;
if (xmethods != NULL)
@@ -3238,9 +3239,13 @@ find_oload_champ (gdb::array_view<value *> args,
{
nparms = TYPE_FN_FIELD_TYPE (methods, ix)->num_fields ();
static_offset = oload_method_static_p (methods, ix);
+ varargs = TYPE_FN_FIELD_TYPE (methods, ix)->has_varargs ();
}
else
- nparms = functions[ix]->type ()->num_fields ();
+ {
+ nparms = functions[ix]->type ()->num_fields ();
+ varargs = functions[ix]->type ()->has_varargs ();
+ }
parm_types.reserve (nparms);
for (jj = 0; jj < nparms; jj++)
@@ -3255,7 +3260,8 @@ find_oload_champ (gdb::array_view<value *> args,
/* Compare parameter types to supplied argument types. Skip
THIS for static methods. */
bv = rank_function (parm_types,
- args.slice (static_offset));
+ args.slice (static_offset),
+ varargs);
if (overload_debug)
{
--
2.35.1
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