[PATCH v14 3/4] Add support for lookup, overload resolution and invocation of C++ debug methods

Siva Chandra
2014-04-15T19:06:03Z

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Attached is the v14 of this part of the patch series. This version
addresses a concern raised by Doug during his v12/v13 review.

v13 posting: https://sourceware.org/ml/gdb-patches/2014-04/msg00147.html
Doug's comment: https://sourceware.org/ml/gdb-patches/2014-04/msg00229.html

Doug's example:

class base
{
public:
virtual int foo (char x) { return x + 1; }
};

class derived : public base
{
public:
int foo (char x) { return x + 2; }
int foo (int x) { return x + 3; }
};

base* ptr = new derived;

Doug's concern:
Suppose we have a debug method for derived::foo (int) and none for
base::foo(char) or derived::foo(char). If I do "p ptr->foo (3)" in
gdb, which method (c++ or debug) should be invoked?

I think, since the invocation happens via the vtable, the foo (char)
version of the derived class should be invoked. My v12/v13 would have
got it wrong. When we do "p ptr->foo(3)", the number 3 is interpreted
to be an int. Consequently, when we perform an overload resolution on
the derived type, GDB would have picked the foo (int) version. To
avoid this, in the attached v14, I have modified to do this:

When (recursively) calling find_overload_match on the dynamic type
object, cast the matching virtual function arguments to the function's
param types explicitly. This way, when overload resolution is
performed on the derived type, the correct function is selected.

Doug's example also made me think of method hiding. If in the same
example above, the derived class did not have foo (char) overridden,
then its foo (int) version hides the base class foo (char) method. In
such cases, we should not look for matching debug methods on the
dynamic type. The attached v14 addresses this also.

2014-04-15 Siva Chandra Reddy <sivachandra@google.com>

* eval.c: #include "extension.h".
(evaluate_subexp_standard): Lookup and invoke C++ methods defined
in extension languages.
* valarith.c: #include "extension.h".
(value_user_defined_cpp_op): Add "src_fn" and "dm_worker"
arguments. Return void. A source match is returned in "src_fn",
and a debug method match is returned in "dm_worker".
(value_user_defined_op): Likewise.
(value_x_binop, value_x_unop): Lookup and invoke
overloaded operator methods defined in extension languages.
* valops.c: #include "extension.h".
(find_method_list): Add "fn_list" and "dm_worker_vec" arguments.
Return void. The list of matching source methods is returned in
"fn_list" and a vector of matching debug method workers is
returned in "dm_worker_vec".
(value_find_oload_method_list): Likewise.
(find_overload_match): Add "dm_worker" parameter. If the best
method match is a debug method, then it is returned in
"dm_worker". All callers updated.
(find_oload_champ): Add "dm_worker_vec" argument. If a caller
wants to find the champion among a set of debug methods, then it
has to pass the debug methods in "dm_worker_vec". All callers
updated.
(value_has_indirect_dynamic_type, cast_args_to_param_types,
equal_param_types_p, derived_hides_base_method): New functions.
* value.h (find_overload_match): Update signature.

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diff --git a/gdb/eval.c b/gdb/eval.c
index 3e62ead..dad1101 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -22,6 +22,7 @@
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
+#include "extension.h"
#include "expression.h"
#include "target.h"
#include "frame.h"
@@ -1592,11 +1593,11 @@ evaluate_subexp_standard (struct type *expect_type,
func_name = (char *) alloca (name_len + 1);
strcpy (func_name, &exp->elts[string_pc + 1].string);

- find_overload_match (&argvec[1], nargs, func_name,
- NON_METHOD, /* not method */
- NULL, NULL, /* pass NULL symbol since
+ find_overload_match (&argvec[1], nargs, func_name,
+ NON_METHOD, /* not method */
+ NULL, NULL, /* pass NULL symbol since
symbol is unknown */
- NULL, &symp, NULL, 0);
+ NULL, &symp, NULL, NULL, 0);

/* Now fix the expression being evaluated. */
exp->elts[save_pos1 + 2].symbol = symp;
@@ -1626,11 +1627,12 @@ evaluate_subexp_standard (struct type *expect_type,
/* Language is C++, do some overload resolution before
evaluation. */
struct value *valp = NULL;
+ struct debug_method_worker *dm_worker = NULL;

(void) find_overload_match (&argvec[1], nargs, tstr,
- METHOD, /* method */
+ METHOD, /* method */
&arg2, /* the object */
- NULL, &valp, NULL,
+ NULL, &valp, NULL, &dm_worker,
&static_memfuncp, 0);

if (op == OP_SCOPE && !static_memfuncp)
@@ -1640,8 +1642,24 @@ evaluate_subexp_standard (struct type *expect_type,
"`this' pointer"),
function_name);
}
- argvec[1] = arg2; /* the ``this'' pointer */
- argvec[0] = valp; /* Use the method found after overload
+
+ /* If a method implemented in an extension language is the best
+ match, then invoke it. */
+ if (dm_worker != NULL)
+ {
+ struct value *ret_val;
+ struct cleanup *dm_worker_cleanup;
+
+ dm_worker_cleanup = make_cleanup (xfree, dm_worker);
+ ret_val = invoke_debug_method (dm_worker, arg2, argvec + 2,
+ nargs - 1);
+ do_cleanups (dm_worker_cleanup);
+
+ return ret_val;
+ }
+
+ argvec[1] = arg2; /* the ``this'' pointer */
+ argvec[0] = valp; /* Use the method found after overload
resolution. */
}
else
@@ -1699,9 +1717,9 @@ evaluate_subexp_standard (struct type *expect_type,

(void) find_overload_match (&argvec[1], nargs,
NULL, /* no need for name */
- NON_METHOD, /* not method */
- NULL, function, /* the function */
- NULL, &symp, NULL, no_adl);
+ NON_METHOD, /* not method */
+ NULL, function, /* the function */
+ NULL, &symp, NULL, NULL, no_adl);

if (op == OP_VAR_VALUE)
{
diff --git a/gdb/valarith.c b/gdb/valarith.c
index 8e863e3..67d90fc 100644
--- a/gdb/valarith.c
+++ b/gdb/valarith.c
@@ -30,6 +30,7 @@
#include <math.h>
#include "infcall.h"
#include "exceptions.h"
+#include "extension.h"

/* Define whether or not the C operator '/' truncates towards zero for
differently signed operands (truncation direction is undefined in C). */
@@ -282,24 +283,37 @@ unop_user_defined_p (enum exp_opcode op, struct value *arg1)
*STATIC_MEMFUNP will be set to 1, and otherwise 0.
The search if performed through find_overload_match which will handle
member operators, non member operators, operators imported implicitly or
- explicitly, and perform correct overload resolution in all of the above
- situations or combinations thereof. */
+ explicitly, operators implemented as debug methods, and perform correct
+ overload resolution in all of the above situations or combinations
+ thereof. If a matching method/function is found in the binary, its
+ corresponding value is returned in SRC_FN. If a debug method is the best
+ match, then the corresponding debug method worker is returned in
+ DM_WORKER. On return, exactly one of SRC_FN, DM_WORKER is non-NULL and
+ the other is NULL. */

-static struct value *
+static void
value_user_defined_cpp_op (struct value **args, int nargs, char *operator,
- int *static_memfuncp)
+ struct value **src_fn,
+ struct debug_method_worker **dm_worker,
+ int *static_memfuncp)
{

struct symbol *symp = NULL;
struct value *valp = NULL;
+ struct debug_method_worker *worker = NULL;

find_overload_match (args, nargs, operator, BOTH /* could be method */,
- &args[0] /* objp */,
- NULL /* pass NULL symbol since symbol is unknown */,
- &valp, &symp, static_memfuncp, 0);
+ &args[0] /* objp */,
+ NULL /* pass NULL symbol since symbol is unknown */,
+ &valp, &symp, &worker, static_memfuncp, 0);

if (valp)
- return valp;
+ {
+ *src_fn = valp;
+ *dm_worker = NULL;
+
+ return;
+ }

if (symp)
{
@@ -307,28 +321,49 @@ value_user_defined_cpp_op (struct value **args, int nargs, char *operator,
expect a reference as its first argument
rather the explicit structure. */
args[0] = value_ind (args[0]);
- return value_of_variable (symp, 0);
+ *src_fn = value_of_variable (symp, 0);
+ *dm_worker = NULL;
+
+ return;
+ }
+
+ if (worker)
+ {
+ *dm_worker = worker;
+ *src_fn = NULL;
+
+ return;
}

error (_("Could not find %s."), operator);
}

-/* Lookup user defined operator NAME. Return a value representing the
- function, otherwise return NULL. */
+/* Lookup user defined operator NAME. If a matching operator is found in the
+ binary, its corresponding value is returned in SRC_FN. If a debug method
+ is the best matching operator, then the corresponding debug method worker
+ is returned in DM_WORKER. On return, exactly one of SRC_FN, DM_WORKER is
+ set to non-NULL and the other is set to NULL. */

-static struct value *
+static void
value_user_defined_op (struct value **argp, struct value **args, char *name,
- int *static_memfuncp, int nargs)
+ int *static_memfuncp, int nargs,
+ struct value **src_fn,
+ struct debug_method_worker **dm_worker)
{
struct value *result = NULL;

if (current_language->la_language == language_cplus)
- result = value_user_defined_cpp_op (args, nargs, name, static_memfuncp);
+ {
+ value_user_defined_cpp_op (args, nargs, name, src_fn, dm_worker,
+ static_memfuncp);
+ }
else
- result = value_struct_elt (argp, args, name, static_memfuncp,
- "structure");
-
- return result;
+ {
+ result = value_struct_elt (argp, args, name, static_memfuncp,
+ "structure");
+ *src_fn = result;
+ *dm_worker = NULL;
+ }
}

/* We know either arg1 or arg2 is a structure, so try to find the right
@@ -345,6 +380,7 @@ value_x_binop (struct value *arg1, struct value *arg2, enum exp_opcode op,
enum exp_opcode otherop, enum noside noside)
{
struct value **argvec;
+ struct debug_method_worker *dm_worker = NULL;
char *ptr;
char tstr[13];
int static_memfuncp;
@@ -359,6 +395,7 @@ value_x_binop (struct value *arg1, struct value *arg2, enum exp_opcode op,
error (_("Can't do that binary op on that type")); /* FIXME be explicit */

argvec = (struct value **) alloca (sizeof (struct value *) * 4);
+ argvec[0] = NULL;
argvec[1] = value_addr (arg1);
argvec[2] = arg2;
argvec[3] = 0;
@@ -471,8 +508,8 @@ value_x_binop (struct value *arg1, struct value *arg2, enum exp_opcode op,
error (_("Invalid binary operation specified."));
}

- argvec[0] = value_user_defined_op (&arg1, argvec + 1, tstr,
- &static_memfuncp, 2);
+ value_user_defined_op (&arg1, argvec + 1, tstr, &static_memfuncp, 2,
+ &argvec[0], &dm_worker);

if (argvec[0])
{
@@ -492,6 +529,14 @@ value_x_binop (struct value *arg1, struct value *arg2, enum exp_opcode op,
return call_function_by_hand (argvec[0], 2 - static_memfuncp,
argvec + 1);
}
+ if (dm_worker != NULL)
+ {
+ struct cleanup *dm_worker_cleanup = make_cleanup (xfree, dm_worker);
+ struct value *ret_val = invoke_debug_method (dm_worker, arg1, &arg2, 1);
+
+ do_cleanups (dm_worker_cleanup);
+ return ret_val;
+ }
throw_error (NOT_FOUND_ERROR,
_("member function %s not found"), tstr);
#ifdef lint
@@ -510,6 +555,7 @@ value_x_unop (struct value *arg1, enum exp_opcode op, enum noside noside)
{
struct gdbarch *gdbarch = get_type_arch (value_type (arg1));
struct value **argvec;
+ struct debug_method_worker *dm_worker;
char *ptr;
char tstr[13], mangle_tstr[13];
int static_memfuncp, nargs;
@@ -523,6 +569,7 @@ value_x_unop (struct value *arg1, enum exp_opcode op, enum noside noside)
error (_("Can't do that unary op on that type")); /* FIXME be explicit */

argvec = (struct value **) alloca (sizeof (struct value *) * 4);
+ argvec[0] = NULL;
argvec[1] = value_addr (arg1);
argvec[2] = 0;

@@ -574,8 +621,8 @@ value_x_unop (struct value *arg1, enum exp_opcode op, enum noside noside)
error (_("Invalid unary operation specified."));
}

- argvec[0] = value_user_defined_op (&arg1, argvec + 1, tstr,
- &static_memfuncp, nargs);
+ value_user_defined_op (&arg1, argvec + 1, tstr, &static_memfuncp, nargs,
+ &argvec[0], &dm_worker);

if (argvec[0])
{
@@ -595,6 +642,14 @@ value_x_unop (struct value *arg1, enum exp_opcode op, enum noside noside)
}
return call_function_by_hand (argvec[0], nargs, argvec + 1);
}
+ if (dm_worker != NULL)
+ {
+ struct cleanup *dm_worker_cleanup = make_cleanup (xfree, dm_worker);
+ struct value *ret_val = invoke_debug_method (dm_worker, arg1, NULL, 0);
+
+ do_cleanups (dm_worker_cleanup);
+ return ret_val;
+ }
throw_error (NOT_FOUND_ERROR,
_("member function %s not found"), tstr);

diff --git a/gdb/valops.c b/gdb/valops.c
index 7f2d5f0..a810f25 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -42,6 +42,7 @@
#include "observer.h"
#include "objfiles.h"
#include "exceptions.h"
+#include "extension.h"

extern unsigned int overload_debug;
/* Local functions. */
@@ -70,8 +71,8 @@ int find_oload_champ_namespace_loop (struct value **, int,
const int no_adl);

static int find_oload_champ (struct value **, int, int,
- struct fn_field *, struct symbol **,
- struct badness_vector **);
+ struct fn_field *, VEC (debug_method_worker_ptr) *,
+ struct symbol **, struct badness_vector **);

static int oload_method_static (int, struct fn_field *, int);

@@ -98,9 +99,10 @@ static CORE_ADDR allocate_space_in_inferior (int);

static struct value *cast_into_complex (struct type *, struct value *);

-static struct fn_field *find_method_list (struct value **, const char *,
- int, struct type *, int *,
- struct type **, int *);
+static void find_method_list (struct value **, const char *,
+ int, struct type *, struct fn_field **, int *,
+ VEC (debug_method_worker_ptr) **,
+ struct type **, int *);

void _initialize_valops (void);

@@ -2255,53 +2257,83 @@ value_struct_elt_bitpos (struct value **argp, int bitpos, struct type *ftype,
}

/* Search through the methods of an object (and its bases) to find a
- specified method. Return the pointer to the fn_field list of
- overloaded instances.
+ specified method. Return the pointer to the fn_field list FN_LIST of
+ overloaded instances defined in the source language. If available
+ and matching, a vector of matching debug methods defined in
+ extension languages are also returned in DM_WORKER_VEC

Helper function for value_find_oload_list.
ARGP is a pointer to a pointer to a value (the object).
METHOD is a string containing the method name.
OFFSET is the offset within the value.
TYPE is the assumed type of the object.
+ FN_LIST The pointer to matching overloaded instances defined in
+ source language.
NUM_FNS is the number of overloaded instances.
+ DM_WORKER_VEC The vector of matching debug method workers.
BASETYPE is set to the actual type of the subobject where the
method is found.
BOFFSET is the offset of the base subobject where the method is found. */

-static struct fn_field *
+static void
find_method_list (struct value **argp, const char *method,
- int offset, struct type *type, int *num_fns,
+ int offset, struct type *type,
+ struct fn_field **fn_list, int *num_fns,
+ VEC (debug_method_worker_ptr) **dm_worker_vec,
struct type **basetype, int *boffset)
{
int i;
- struct fn_field *f;
- CHECK_TYPEDEF (type);
+ struct fn_field *f = NULL;

- *num_fns = 0;
+ CHECK_TYPEDEF (type);

- /* First check in object itself. */
- for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
+ /* First check in object itself.
+ This function is called recursively to search through base classes.
+ If there is a source method match found at some stage, then we need not
+ look for source methods in consequent recursive calls. */
+ if (fn_list != NULL && (*fn_list) == NULL)
{
- /* pai: FIXME What about operators and type conversions? */
- const char *fn_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
-
- if (fn_field_name && (strcmp_iw (fn_field_name, method) == 0))
+ for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
{
- int len = TYPE_FN_FIELDLIST_LENGTH (type, i);
- struct fn_field *f = TYPE_FN_FIELDLIST1 (type, i);
+ /* pai: FIXME What about operators and type conversions? */
+ const char *fn_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
+
+ if (fn_field_name && (strcmp_iw (fn_field_name, method) == 0))
+ {
+ int len = TYPE_FN_FIELDLIST_LENGTH (type, i);
+ f = TYPE_FN_FIELDLIST1 (type, i);
+ *fn_list = f;

- *num_fns = len;
- *basetype = type;
- *boffset = offset;
+ *num_fns = len;
+ *basetype = type;
+ *boffset = offset;

- /* Resolve any stub methods. */
- check_stub_method_group (type, i);
+ /* Resolve any stub methods. */
+ check_stub_method_group (type, i);

- return f;
+ break;
+ }
}
}

- /* Not found in object, check in base subobjects. */
+ /* Unlike source methods, debug methods can be accumulated over successive
+ recursive calls. In other words, a debug method named 'm' in a class
+ will not hide a debug method named 'm' in its base class(es). */
+ if (dm_worker_vec)
+ {
+ VEC (debug_method_worker_ptr) *worker_vec = NULL, *new_vec = NULL;
+
+ worker_vec = get_matching_debug_method_workers (type, method);
+ new_vec = VEC_merge (debug_method_worker_ptr, *dm_worker_vec, worker_vec);
+
+ VEC_free (debug_method_worker_ptr, *dm_worker_vec);
+ VEC_free (debug_method_worker_ptr, worker_vec);
+ *dm_worker_vec = new_vec;
+ }
+
+ /* If source methods are not found in current class, look for them in the
+ base classes. We have to go through the base classes to gather extension
+ methods anyway. */
for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
{
int base_offset;
@@ -2318,28 +2350,35 @@ find_method_list (struct value **argp, const char *method,
{
base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
}
- f = find_method_list (argp, method, base_offset + offset,
- TYPE_BASECLASS (type, i), num_fns,
- basetype, boffset);
- if (f)
- return f;
+
+ find_method_list (argp, method, base_offset + offset,
+ TYPE_BASECLASS (type, i), fn_list, num_fns,
+ dm_worker_vec, basetype, boffset);
}
- return NULL;
}

-/* Return the list of overloaded methods of a specified name.
+/* Return the list of overloaded methods of a specified name. The methods
+ could be those GDB finds in the binary, or debug methods. Methods found
+ in the binary are returned in FN_LIST, and debug methods are returned in
+ DM_WORKER_VEC.

ARGP is a pointer to a pointer to a value (the object).
METHOD is the method name.
OFFSET is the offset within the value contents.
+ FN_LIST The pointer to matching overloaded instances defined in
+ source language.
NUM_FNS is the number of overloaded instances.
+ DM_WORKER_VEC The vector of matching debug method workers defined in
+ extension languages.
BASETYPE is set to the type of the base subobject that defines the
method.
BOFFSET is the offset of the base subobject which defines the method. */

-static struct fn_field *
+static void
value_find_oload_method_list (struct value **argp, const char *method,
- int offset, int *num_fns,
+ int offset, struct fn_field **fn_list,
+ int *num_fns,
+ VEC (debug_method_worker_ptr) **dm_worker_vec,
struct type **basetype, int *boffset)
{
struct type *t;
@@ -2361,8 +2400,124 @@ value_find_oload_method_list (struct value **argp, const char *method,
error (_("Attempt to extract a component of a "
"value that is not a struct or union"));

- return find_method_list (argp, method, 0, t, num_fns,
- basetype, boffset);
+ /* Clear the lists. */
+ if (fn_list != NULL)
+ {
+ *fn_list = NULL;
+ *num_fns = 0;
+ }
+ if (dm_worker_vec != NULL)
+ *dm_worker_vec = NULL;
+
+ find_method_list (argp, method, 0, t, fn_list, num_fns, dm_worker_vec,
+ basetype, boffset);
+}
+
+/* Return the dynamic type of OBJ. NULL is returned if OBJ does not have any
+ dynamic type. */
+
+static struct type *
+value_has_indirect_dynamic_type (struct value *obj)
+{
+ struct type *stype, *dtype, *dtype_ind;
+
+ stype = check_typedef (TYPE_TARGET_TYPE (value_type (obj)));
+ dtype_ind = value_rtti_indirect_type (obj, NULL, NULL, NULL);
+ dtype = dtype_ind ? check_typedef (TYPE_TARGET_TYPE (dtype_ind)) : stype;
+
+ if (class_types_same_p (stype, dtype))
+ return NULL;
+ else
+ return dtype_ind;
+}
+
+/* Casts the arguments in the array ARGS to the types of the parameters of
+ the M-th method in FNS_PTR. The length of the array ARGS is given by
+ NARGS. This is a helper function for find_overload_match. */
+
+static void
+cast_args_to_param_types (struct value **args, int nargs,
+ struct fn_field *fns_ptr, int m)
+{
+ int i;
+
+ gdb_assert (TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr, m)) == nargs);
+
+ for (i = 1; i < nargs; i++)
+ {
+ struct type *param_type = TYPE_FN_FIELD_ARGS (fns_ptr, m)[i].type;
+ struct type *arg_type = check_typedef (value_type (args[i]));
+
+ CHECK_TYPEDEF (param_type);
+ if (TYPE_CODE (param_type) == TYPE_CODE_REF
+ && TYPE_CODE (arg_type) != TYPE_CODE_REF)
+ param_type = TYPE_TARGET_TYPE (param_type);
+
+ args[i] = value_cast (param_type, args[i]);
+ }
+}
+
+/* Checks if the N1-th method in FNS_PTR1 has exactly the same parameters
+ as that of the N2-th method in FNS_PTR2.
+ Returns 1 is equal, zero otherwise. */
+
+static int
+equal_param_types_p (struct fn_field *fns_ptr1, int n1,
+ struct fn_field *fns_ptr2, int n2)
+{
+ int i;
+
+ if (TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr1, n1))
+ != TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr2, n2)))
+ return 0;
+
+ for (i = 1; i < TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr1, n1)); i++)
+ {
+ struct type *type1 = TYPE_FN_FIELD_ARGS (fns_ptr1, n1)[i].type;
+ struct type *type2 = TYPE_FN_FIELD_ARGS (fns_ptr2, n2)[i].type;
+
+ if (!types_deeply_equal (type1, type2))
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Checks if the derived type DTYPE hides a method NAME of its base class.
+ The base class method is the M-th method in FNS_PTR. */
+
+static int
+derived_hides_base_method (struct type *dtype, const char *name,
+ struct fn_field *fns_ptr, int m)
+{
+ int i, ret_val = 0;
+
+ dtype = check_typedef (dtype);
+ gdb_assert (TYPE_CODE (dtype) == TYPE_CODE_STRUCT);
+
+ for (i = 0; i < TYPE_NFN_FIELDS (dtype); i++)
+ {
+ const char *fn_field_name = TYPE_FN_FIELDLIST_NAME (dtype, i);
+
+ if (fn_field_name && (strcmp_iw (fn_field_name, name) == 0))
+ {
+ int j;
+
+ /* If a method with the same name is found in the dynamic type,
+ then assume that it hides the base method until a method with
+ matching param types is found. */
+ ret_val = 1;
+
+ for (j = 0; j < TYPE_FN_FIELDLIST_LENGTH (dtype, i); j++)
+ {
+ if (equal_param_types_p (TYPE_FN_FIELDLIST1 (dtype, i), j,
+ fns_ptr, m))
+ return 0;
+ }
+ }
+ }
+
+ return ret_val;
}

/* Given an array of arguments (ARGS) (which includes an
@@ -2390,9 +2545,10 @@ value_find_oload_method_list (struct value **argp, const char *method,
Return value is an integer: 0 -> good match, 10 -> debugger applied
non-standard coercions, 100 -> incompatible.

- If a method is being searched for, VALP will hold the value.
- If a non-method is being searched for, SYMP will hold the symbol
- for it.
+ If the best match is a debug method then DM_WORKER will hold the matching
+ debug method worker. Otherwise, VALP will hold the value if a method is
+ being searched for, or SYMP will hold the symbol for the matching function
+ if a non-method is being searched for.

If a method is being searched for, and it is a static method,
then STATICP will point to a non-zero value.
@@ -2410,6 +2566,7 @@ find_overload_match (struct value **args, int nargs,
const char *name, enum oload_search_type method,
struct value **objp, struct symbol *fsym,
struct value **valp, struct symbol **symp,
+ struct debug_method_worker **dm_worker,
int *staticp, const int no_adl)
{
struct value *obj = (objp ? *objp : NULL);
@@ -2417,16 +2574,24 @@ find_overload_match (struct value **args, int nargs,
/* Index of best overloaded function. */
int func_oload_champ = -1;
int method_oload_champ = -1;
+ int src_method_oload_champ = -1;
+ int src_method_oload_champ_orig = -1;
+ int ext_method_oload_champ = -1;
+ int src_and_ext_equal = 0;

/* The measure for the current best match. */
struct badness_vector *method_badness = NULL;
struct badness_vector *func_badness = NULL;
+ struct badness_vector *ext_method_badness = NULL;
+ struct badness_vector *src_method_badness = NULL;

struct value *temp = obj;
/* For methods, the list of overloaded methods. */
struct fn_field *fns_ptr = NULL;
/* For non-methods, the list of overloaded function symbols. */
struct symbol **oload_syms = NULL;
+ /* For debug methods, the VEC of debug method workers. */
+ VEC (debug_method_worker_ptr) *dm_worker_vec = NULL;
/* Number of overloaded instances being considered. */
int num_fns = 0;
struct type *basetype = NULL;
@@ -2438,6 +2603,8 @@ find_overload_match (struct value **args, int nargs,
const char *func_name = NULL;
enum oload_classification match_quality;
enum oload_classification method_match_quality = INCOMPATIBLE;
+ enum oload_classification src_method_match_quality = INCOMPATIBLE;
+ enum oload_classification ext_method_match_quality = INCOMPATIBLE;
enum oload_classification func_match_quality = INCOMPATIBLE;

/* Get the list of overloaded methods or functions. */
@@ -2466,12 +2633,12 @@ find_overload_match (struct value **args, int nargs,
}

/* Retrieve the list of methods with the name NAME. */
- fns_ptr = value_find_oload_method_list (&temp, name,
- 0, &num_fns,
- &basetype, &boffset);
+ value_find_oload_method_list (&temp, name, 0, &fns_ptr, &num_fns,
+ dm_worker ? &dm_worker_vec : NULL,
+ &basetype, &boffset);
/* If this is a method only search, and no methods were found
the search has faild. */
- if (method == METHOD && (!fns_ptr || !num_fns))
+ if (method == METHOD && (!fns_ptr || !num_fns) && !dm_worker_vec)
error (_("Couldn't find method %s%s%s"),
obj_type_name,
(obj_type_name && *obj_type_name) ? "::" : "",
@@ -2482,18 +2649,87 @@ find_overload_match (struct value **args, int nargs,
if (fns_ptr)
{
gdb_assert (TYPE_DOMAIN_TYPE (fns_ptr[0].type) != NULL);
- method_oload_champ = find_oload_champ (args, nargs,
- num_fns, fns_ptr,
- NULL, &method_badness);

- method_match_quality =
- classify_oload_match (method_badness, nargs,
- oload_method_static (method, fns_ptr,
- method_oload_champ));
+ src_method_oload_champ = find_oload_champ (args, nargs,
+ num_fns, fns_ptr, NULL,
+ NULL, &src_method_badness);
+
+ src_method_match_quality = classify_oload_match
+ (src_method_badness, nargs,
+ oload_method_static (method, fns_ptr, src_method_oload_champ));

- make_cleanup (xfree, method_badness);
+ make_cleanup (xfree, src_method_badness);
}

+ if (dm_worker && VEC_length (debug_method_worker_ptr, dm_worker_vec))
+ {
+ ext_method_oload_champ = find_oload_champ (args, nargs,
+ 0, NULL, dm_worker_vec,
+ NULL, &ext_method_badness);
+ ext_method_match_quality = classify_oload_match (ext_method_badness,
+ nargs, 0);
+ make_cleanup (xfree, ext_method_badness);
+ make_debug_method_worker_vec_cleanup (dm_worker_vec);
+ }
+
+ if (src_method_oload_champ >= 0 && ext_method_oload_champ >= 0)
+ {
+ switch (compare_badness (ext_method_badness, src_method_badness))
+ {
+ case 0: /* Src method and debug method are equally good. */
+ src_and_ext_equal = 1;
+ /* If src method and debug method are equally good, then debug
+ method should be the winner. Hence, fall through to the
+ case where a debug method is better than the source
+ method, except when the debug method match quality is
+ non-standard. */
+ /* FALLTHROUGH */
+ case 1: /* Src method and ext method are incompatible. */
+ /* If ext method match is not standard, then let source method
+ win. Otherwise, fallthrough to let debug method win. */
+ if (ext_method_match_quality != STANDARD)
+ {
+ method_oload_champ = src_method_oload_champ;
+ method_badness = src_method_badness;
+ ext_method_oload_champ = -1;
+ method_match_quality = src_method_match_quality;
+ break;
+ }
+ /* FALLTHROUGH */
+ case 2: /* Ext method is champion. */
+ method_oload_champ = ext_method_oload_champ;
+ method_badness = ext_method_badness;
+ /* We save the source overload champ index so that it can be
+ used to determine whether the source method is virtual
+ later in this function. */
+ src_method_oload_champ_orig = src_method_oload_champ;
+ src_method_oload_champ = -1;
+ method_match_quality = ext_method_match_quality;
+ break;
+ case 3: /* Src method is champion. */
+ method_oload_champ = src_method_oload_champ;
+ method_badness = src_method_badness;
+ ext_method_oload_champ = -1;
+ method_match_quality = src_method_match_quality;
+ break;
+ default:
+ gdb_assert_not_reached ("Internal error: unexpected overload "
+ "comparison result");
+ break;
+ }
+ }
+ else if (src_method_oload_champ >= 0)
+ {
+ method_oload_champ = src_method_oload_champ;
+ method_badness = src_method_badness;
+ method_match_quality = src_method_match_quality;
+ }
+ else if (ext_method_oload_champ >= 0)
+ {
+ method_oload_champ = ext_method_oload_champ;
+ method_badness = ext_method_badness;
+ method_match_quality = ext_method_match_quality;
+ }
}

if (method == NON_METHOD || method == BOTH)
@@ -2636,21 +2872,6 @@ find_overload_match (struct value **args, int nargs,
func_name);
}

- if (staticp != NULL)
- *staticp = oload_method_static (method, fns_ptr, method_oload_champ);
-
- if (method_oload_champ >= 0)
- {
- if (TYPE_FN_FIELD_VIRTUAL_P (fns_ptr, method_oload_champ))
- *valp = value_virtual_fn_field (&temp, fns_ptr, method_oload_champ,
- basetype, boffset);
- else
- *valp = value_fn_field (&temp, fns_ptr, method_oload_champ,
- basetype, boffset);
- }
- else
- *symp = oload_syms[func_oload_champ];
-
if (objp)
{
struct type *temp_type = check_typedef (value_type (temp));
@@ -2660,10 +2881,112 @@ find_overload_match (struct value **args, int nargs,
&& (TYPE_CODE (objtype) == TYPE_CODE_PTR
|| TYPE_CODE (objtype) == TYPE_CODE_REF))
{
- temp = value_addr (temp);
+ *objp = value_addr (temp);
+ }
+ else
+ *objp = temp;
+ }
+
+ if (staticp != NULL)
+ *staticp = oload_method_static (method, fns_ptr, method_oload_champ);
+
+ if (method_oload_champ >= 0)
+ {
+ if (src_method_oload_champ >= 0)
+ {
+ /* Even if the source method was the winner, it could be a virtual
+ function. In such a case, we should look for the possibility of
+ debug methods defined on the object's dynamic type. */
+ if (TYPE_FN_FIELD_VIRTUAL_P (fns_ptr, method_oload_champ))
+ {
+ struct type *dtype;
+
+ dtype = value_has_indirect_dynamic_type (args[0]);
+ /* Look for better methods in the dynamic type only if the
+ dynamic type does not hide the base class virtual method. */
+ if (dtype != NULL
+ && !derived_hides_base_method (TYPE_TARGET_TYPE (dtype),
+ name, fns_ptr,
+ method_oload_champ))
+ {
+ /* If the object has a dynamic type, then look for matching
+ methods for its dynamic type. */
+ args[0] = value_cast (dtype, args[0]);
+ do_cleanups (all_cleanups);
+ /* Even if the derived class does not hide the base class
+ method, it could define another method with the same name
+ but with compatible parameters. Avoid the chance of
+ picking up the wrong function by explicitly casting the
+ args to the virtual function param types.
+
+ Example:
+
+ class base
+ {
+ public:
+ virtual int foo (char i);
+ };
+
+ class derived : public base
+ {
+ public:
+ virtual int foo (char i);
+ int foo (int i);
+ };
+
+ If the arg to base::foo was as int, then looking for
+ matching methods in the dynamic object will match foo(int)
+ and not foo (char) even though the derived class overrides
+ (does not hide) the base class virtual method. */
+ cast_args_to_param_types (args, nargs, fns_ptr,
+ method_oload_champ);
+ return find_overload_match (args, nargs, name, method,
+ objp, fsym, valp, symp, dm_worker,
+ staticp, no_adl);
+ }
+ else
+ *valp = value_virtual_fn_field (&temp, fns_ptr,
+ method_oload_champ,
+ basetype, boffset);
+ }
+ else
+ *valp = value_fn_field (&temp, fns_ptr, method_oload_champ,
+ basetype, boffset);
+ }
+ else
+ {
+ /* Debug methods cannot be virtual. However, if a debug method is as
+ good as the source method, and if the source method is virtual, we
+ should look for the possibility of better matching methods defined
+ for the dynamic type of the object. */
+ if (src_and_ext_equal
+ && TYPE_FN_FIELD_VIRTUAL_P (fns_ptr, src_method_oload_champ_orig))
+ {
+ struct type *dtype;
+
+ dtype = value_has_indirect_dynamic_type (args[0]);
+ if (dtype != NULL
+ && !derived_hides_base_method (TYPE_TARGET_TYPE (dtype),
+ name, fns_ptr,
+ src_method_oload_champ_orig))
+ {
+ args[0] = value_cast (dtype, args[0]);
+ do_cleanups (all_cleanups);
+ cast_args_to_param_types (args, nargs, fns_ptr,
+ src_method_oload_champ_orig);
+ return find_overload_match (args, nargs, name, method,
+ objp, fsym, valp, symp, dm_worker,
+ staticp, no_adl);
+ }
+ }
+
+ *dm_worker = clone_debug_method_worker (
+ VEC_index (debug_method_worker_ptr, dm_worker_vec,
+ ext_method_oload_champ));
}
- *objp = temp;
}
+ else
+ *symp = oload_syms[func_oload_champ];

do_cleanups (all_cleanups);

@@ -2798,7 +3121,7 @@ find_oload_champ_namespace_loop (struct value **args, int nargs,
++num_fns;

new_oload_champ = find_oload_champ (args, nargs, num_fns,
- NULL, new_oload_syms,
+ NULL, NULL, new_oload_syms,
&new_oload_champ_bv);

/* Case 1: We found a good match. Free earlier matches (if any),
@@ -2836,9 +3159,13 @@ find_oload_champ_namespace_loop (struct value **args, int nargs,

/* Look for a function to take NARGS args of ARGS. Find
the best match from among the overloaded methods or functions
- given by FNS_PTR or OLOAD_SYMS, respectively. One, and only one of
- FNS_PTR and OLOAD_SYMS can be non-NULL. The number of
- methods/functions in the non-NULL list is given by NUM_FNS.
+ given by FNS_PTR or OLOAD_SYMS or DM_WORKER_VEC, respectively.
+ One, and only one of FNS_PTR, OLOAD_SYMS and DM_WORKER_VEC can be
+ non-NULL.
+
+ If DM_WORKER_VEC is NULL, then the length of the arrays FNS_PTR
+ or OLOAD_SYMS (whichever is non-NULL) is specified in NUM_FNS.
+
Return the index of the best match; store an indication of the
quality of the match in OLOAD_CHAMP_BV.

@@ -2847,10 +3174,13 @@ find_oload_champ_namespace_loop (struct value **args, int nargs,
static int
find_oload_champ (struct value **args, int nargs,
int num_fns, struct fn_field *fns_ptr,
+ VEC (debug_method_worker_ptr) *dm_worker_vec,
struct symbol **oload_syms,
struct badness_vector **oload_champ_bv)
{
int ix;
+ int fn_count;
+ int dm_worker_vec_n = VEC_length (debug_method_worker_ptr, dm_worker_vec);
/* A measure of how good an overloaded instance is. */
struct badness_vector *bv;
/* Index of best overloaded function. */
@@ -2860,40 +3190,49 @@ find_oload_champ (struct value **args, int nargs,
/* 0 => no ambiguity, 1 => two good funcs, 2 => incomparable funcs. */

/* A champion can be found among methods alone, or among functions
- alone, but not both. */
- gdb_assert ((fns_ptr != NULL) + (oload_syms != NULL) == 1);
+ alone, or in debug methods alone, but not in more than one of these
+ groups. */
+ gdb_assert ((fns_ptr != NULL) + (oload_syms != NULL) + (dm_worker_vec != NULL)
+ == 1);

*oload_champ_bv = NULL;

+ fn_count = (dm_worker_vec != NULL
+ ? VEC_length (debug_method_worker_ptr, dm_worker_vec)
+ : num_fns);
/* Consider each candidate in turn. */
- for (ix = 0; ix < num_fns; ix++)
+ for (ix = 0; ix < fn_count; ix++)
{
int jj;
- int static_offset;
+ int static_offset = 0;
int nparms;
struct type **parm_types;
+ struct debug_method_worker *worker = NULL;

- if (fns_ptr != NULL)
+ if (dm_worker_vec != NULL)
{
- nparms = TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr, ix));
- static_offset = oload_method_static (1, fns_ptr, ix);
+ worker = VEC_index (debug_method_worker_ptr, dm_worker_vec, ix);
+ parm_types = get_debug_method_arg_types (worker, &nparms);
}
else
{
- /* If it's not a method, this is the proper place. */
- nparms = TYPE_NFIELDS (SYMBOL_TYPE (oload_syms[ix]));
- static_offset = 0;
+ if (fns_ptr != NULL)
+ {
+ nparms = TYPE_NFIELDS (TYPE_FN_FIELD_TYPE (fns_ptr, ix));
+ static_offset = oload_method_static (1, fns_ptr, ix);
+ }
+ else
+ nparms = TYPE_NFIELDS (SYMBOL_TYPE (oload_syms[ix]));
+
+ parm_types = (struct type **)
+ xmalloc (nparms * (sizeof (struct type *)));
+ for (jj = 0; jj < nparms; jj++)
+ parm_types[jj] = (fns_ptr != NULL
+ ? (TYPE_FN_FIELD_ARGS (fns_ptr, ix)[jj].type)
+ : TYPE_FIELD_TYPE (SYMBOL_TYPE (oload_syms[ix]),
+ jj));
}

- /* Prepare array of parameter types. */
- parm_types = (struct type **)
- xmalloc (nparms * (sizeof (struct type *)));
- for (jj = 0; jj < nparms; jj++)
- parm_types[jj] = (fns_ptr != NULL
- ? (TYPE_FN_FIELD_ARGS (fns_ptr, ix)[jj].type)
- : TYPE_FIELD_TYPE (SYMBOL_TYPE (oload_syms[ix]),
- jj));
-
/* Compare parameter types to supplied argument types. Skip
THIS for static methods. */
bv = rank_function (parm_types, nparms,
@@ -2927,10 +3266,14 @@ find_oload_champ (struct value **args, int nargs,
xfree (parm_types);
if (overload_debug)
{
- if (fns_ptr)
+ if (fns_ptr != NULL)
fprintf_filtered (gdb_stderr,
"Overloaded method instance %s, # of parms %d\n",
fns_ptr[ix].physname, nparms);
+ else if (dm_worker_vec != NULL)
+ fprintf_filtered (gdb_stderr,
+ "Debug method worker, # of parms %d\n",
+ nparms);
else
fprintf_filtered (gdb_stderr,
"Overloaded function instance "
diff --git a/gdb/value.h b/gdb/value.h
index 9425a0e..d37e7f9 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -31,6 +31,7 @@ struct type;
struct ui_file;
struct language_defn;
struct value_print_options;
+struct debug_method_worker;

/* The structure which defines the type of a value. It should never
be possible for a program lval value to survive over a call to the
@@ -690,6 +691,7 @@ extern int find_overload_match (struct value **args, int nargs,
enum oload_search_type method,
struct value **objp, struct symbol *fsym,
struct value **valp, struct symbol **symp,
+ struct debug_method_worker **dm_worker,
int *staticp, const int no_adl);

extern struct value *value_field (struct value *arg1, int fieldno);