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re PR c++/61636 (generic lambda: segfault / "cannot call member function without object") 

PR c++/61636
	* cp-tree.h (maybe_generic_this_capture): Declare.
	* lambda.c (resolvable_dummy_lambda): New, broken out of ...
	(maybe_resolve_dummy): ... here.  Call it.
	(maybe_generic_this_capture): New.
	* parser.c (cp_parser_postfix_expression): Speculatively capture
	this in generic lambda in unresolved member function call.
	* pt.c (tsubst_copy_and_build): Force hard error from failed
	member function lookup in generic lambda.

	PR c++/61636
	* g++.dg/cpp1y/pr61636-1.C: New.
	* g++.dg/cpp1y/pr61636-2.C: New.
	* g++.dg/cpp1y/pr61636-3.C: New.

From-SVN: r244544
This commit is contained in:
Nathan Sidwell 2017-01-17 18:22:34 +00:00 committed by Nathan Sidwell
parent f46fe37e86
commit 8ddfdbc265
9 changed files with 231 additions and 25 deletions
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12
gcc/cp/ChangeLog
View File

@ -1,3 +1,15 @@
2017-01-17 Nathan Sidwell <nathan@acm.org>
PR c++/61636
* cp-tree.h (maybe_generic_this_capture): Declare.
* lambda.c (resolvable_dummy_lambda): New, broken out of ...
(maybe_resolve_dummy): ... here. Call it.
(maybe_generic_this_capture): New.
* parser.c (cp_parser_postfix_expression): Speculatively capture
this in generic lambda in unresolved member function call.
* pt.c (tsubst_copy_and_build): Force hard error from failed
member function lookup in generic lambda.
2017-01-17 Aldy Hernandez <aldyh@redhat.com>
PR c++/70565

1
gcc/cp/cp-tree.h
View File

@ -6551,6 +6551,7 @@ extern bool is_capture_proxy (tree);
extern bool is_normal_capture_proxy (tree);
extern void register_capture_members (tree);
extern tree lambda_expr_this_capture (tree, bool);
extern void maybe_generic_this_capture (tree, tree);
extern tree maybe_resolve_dummy (tree, bool);
extern tree current_nonlambda_function (void);
extern tree nonlambda_method_basetype (void);

61
gcc/cp/lambda.c
View File

@ -793,16 +793,14 @@ lambda_expr_this_capture (tree lambda, bool add_capture_p)
return result;
}
/* We don't want to capture 'this' until we know we need it, i.e. after
overload resolution has chosen a non-static member function. At that
point we call this function to turn a dummy object into a use of the
'this' capture. */
/* Return the current LAMBDA_EXPR, if this is a resolvable dummy
object. NULL otherwise.. */
tree
maybe_resolve_dummy (tree object, bool add_capture_p)
static tree
resolvable_dummy_lambda (tree object)
{
if (!is_dummy_object (object))
return object;
return NULL_TREE;
tree type = TYPE_MAIN_VARIANT (TREE_TYPE (object));
gcc_assert (!TYPE_PTR_P (type));
@ -812,18 +810,55 @@ maybe_resolve_dummy (tree object, bool add_capture_p)
&& LAMBDA_TYPE_P (current_class_type)
&& lambda_function (current_class_type)
&& DERIVED_FROM_P (type, current_nonlambda_class_type ()))
{
/* In a lambda, need to go through 'this' capture. */
tree lam = CLASSTYPE_LAMBDA_EXPR (current_class_type);
tree cap = lambda_expr_this_capture (lam, add_capture_p);
if (cap && cap != error_mark_node)
return CLASSTYPE_LAMBDA_EXPR (current_class_type);
return NULL_TREE;
}
/* We don't want to capture 'this' until we know we need it, i.e. after
overload resolution has chosen a non-static member function. At that
point we call this function to turn a dummy object into a use of the
'this' capture. */
tree
maybe_resolve_dummy (tree object, bool add_capture_p)
{
if (tree lam = resolvable_dummy_lambda (object))
if (tree cap = lambda_expr_this_capture (lam, add_capture_p))
if (cap != error_mark_node)
object = build_x_indirect_ref (EXPR_LOCATION (object), cap,
RO_NULL, tf_warning_or_error);
}
return object;
}
/* When parsing a generic lambda containing an argument-dependent
member function call we defer overload resolution to instantiation
time. But we have to know now whether to capture this or not.
Do that if FNS contains any non-static fns.
The std doesn't anticipate this case, but I expect this to be the
outcome of discussion. */
void
maybe_generic_this_capture (tree object, tree fns)
{
if (tree lam = resolvable_dummy_lambda (object))
if (!LAMBDA_EXPR_THIS_CAPTURE (lam))
{
/* We've not yet captured, so look at the function set of
interest. */
if (BASELINK_P (fns))
fns = BASELINK_FUNCTIONS (fns);
for (; fns; fns = OVL_NEXT (fns))
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (OVL_CURRENT (fns)))
{
/* Found a non-static member. Capture this. */
lambda_expr_this_capture (lam, true);
break;
}
}
}
/* Returns the innermost non-lambda function. */
tree

1
gcc/cp/parser.c
View File

@ -6971,6 +6971,7 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
|| type_dependent_expression_p (fn)
|| any_type_dependent_arguments_p (args)))
{
maybe_generic_this_capture (instance, fn);
postfix_expression
= build_nt_call_vec (postfix_expression, args);
release_tree_vector (args);

45
gcc/cp/pt.c
View File

@ -17142,19 +17142,34 @@ tsubst_copy_and_build (tree t,
if (unq != function)
{
tree fn = unq;
if (INDIRECT_REF_P (fn))
fn = TREE_OPERAND (fn, 0);
if (TREE_CODE (fn) == COMPONENT_REF)
fn = TREE_OPERAND (fn, 1);
if (is_overloaded_fn (fn))
fn = get_first_fn (fn);
if (permerror (EXPR_LOC_OR_LOC (t, input_location),
"%qD was not declared in this scope, "
"and no declarations were found by "
"argument-dependent lookup at the point "
"of instantiation", function))
/* In a lambda fn, we have to be careful to not
introduce new this captures. Legacy code can't
be using lambdas anyway, so it's ok to be
stricter. */
bool in_lambda = (current_class_type
&& LAMBDA_TYPE_P (current_class_type));
char const *msg = "%qD was not declared in this scope, "
"and no declarations were found by "
"argument-dependent lookup at the point "
"of instantiation";
bool diag = true;
if (in_lambda)
error_at (EXPR_LOC_OR_LOC (t, input_location),
msg, function);
else
diag = permerror (EXPR_LOC_OR_LOC (t, input_location),
msg, function);
if (diag)
{
tree fn = unq;
if (INDIRECT_REF_P (fn))
fn = TREE_OPERAND (fn, 0);
if (TREE_CODE (fn) == COMPONENT_REF)
fn = TREE_OPERAND (fn, 1);
if (is_overloaded_fn (fn))
fn = get_first_fn (fn);
if (!DECL_P (fn))
/* Can't say anything more. */;
else if (DECL_CLASS_SCOPE_P (fn))
@ -17177,7 +17192,13 @@ tsubst_copy_and_build (tree t,
inform (DECL_SOURCE_LOCATION (fn),
"%qD declared here, later in the "
"translation unit", fn);
if (in_lambda)
{
release_tree_vector (call_args);
RETURN (error_mark_node);
}
}
function = unq;
}
}

8
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,10 @@
2017-01-17 Nathan Sidwell <nathan@acm.org>
PR c++/61636
* g++.dg/cpp1y/pr61636-1.C: New.
* g++.dg/cpp1y/pr61636-2.C: New.
* g++.dg/cpp1y/pr61636-3.C: New.
2017-01-17 Martin Sebor <msebor@redhat.com>
PR testsuite/79115
@ -214,6 +221,7 @@
PR target/79004
* gcc.target/powerpc/pr79004.c: New test.
2017-01-12 Martin Sebor <msebor@redhat.com>
* gcc.dg/pr78138.c: Adjust.

31
gcc/testsuite/g++.dg/cpp1y/pr61636-1.C Normal file
View File

@ -0,0 +1,31 @@
// PR c++/61636
// { dg-do compile { target c++14 } }
// ICE because we figure this capture too late.
struct Base
{
void Bar (int);
};
struct A : Base {
void b ();
void Foo (int);
using Base::Bar;
template <typename T> void Baz (T);
};
void A::b() {
auto lam = [&](auto asdf) { Foo (asdf); };
lam (0);
auto lam1 = [&](auto asdf) { Bar (asdf); };
lam1 (0);
auto lam2 = [&](auto asdf) { Baz (asdf); };
lam2 (0);
}

72
gcc/testsuite/g++.dg/cpp1y/pr61636-2.C Normal file
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@ -0,0 +1,72 @@
// PR c++/61636
// { dg-do run { target c++14 } }
// Check we don't capture this (too) unnecessarily
struct A {
int b ();
void f (int) {}
static void f (double) {}
static void g (int) {}
static void g (double) {}
};
struct O {
void x (int) {}
static void x (double) {}
};
namespace N {
void y (double) {}
}
int Check (bool expect, unsigned size)
{
return (expect ? sizeof (void *) : 1) != size;
}
int A::b() {
int r = 0;
// one of the functions is non-static
auto l0 = [&](auto z) { f (z); };
r += Check (true, sizeof l0);
l0(0.0); // doesn't need this capture for A::f(double), but too late
l0 (0); // Needs this capture for A::f(int)
// no fn is non-static.
auto l00 = [&](auto z) { g (z); };
r += Check (false, sizeof l00);
l00(0.0);
l00 (0);
// sizeof isn't an evaluation context, so no this capture
auto l1 = [&](auto z) { sizeof (f (z), 1); };
r += Check (false, sizeof l1);
l1(0.0); l1 (0);
auto l2 = [&](auto) { f (2.4); };
auto l3 = [&](auto) { f (0); };
l2(0); l3(0); l2(0.0); l3 (0.0);
r += Check (false, sizeof l2);
r += Check (true, sizeof l3);
auto l4 = [&](auto) { O::x (2.4); };
auto l5 = [&](auto) { N::y (2.4); };
auto l6 = [&](auto) { };
l4(0); l5(0); l6(0);
l4(0.0); l5(0.0); l6(0.0);
r += Check (false, sizeof l4);
r += Check (false, sizeof l5);
r += Check (false, sizeof l6);
return r;
}
int main ()
{
A a;
return a.b () ? 1 : 0;
}

25
gcc/testsuite/g++.dg/cpp1y/pr61636-3.C Normal file
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@ -0,0 +1,25 @@
// PR c++/61636
// { dg-do compile { target c++14 } }
// permissiveness doesn't make this permitted
// { dg-additional-options "-fpermissive" }
// ICE because we attempt to use dependent Foo during error recovery
// and die with an unexpected this capture need.
template <typename T> struct Base
{
void Foo (int);
};
template <typename T> struct A : Base<T> {
void b ();
};
template <typename T> void A<T>::b() {
auto lam = [&](auto asdf) { Foo (asdf); }; // { dg-error "not declared" }
lam (T(0));
}
template void A<int>::b ();