[PATCH] c++: Fix up diagnostics about taking address of an immediate member function [PR102753]
Jakub Jelinek
jakub@redhat.com
Wed Nov 24 18:02:57 GMT 2021
On Wed, Nov 24, 2021 at 05:02:03PM +0100, Jakub Jelinek via Gcc-patches wrote:
> Unfortunately, the location wrappers are optimized away before we get a
> chance to use them in cp_fold_r.
> So, on the following patch, we get the location right on PTRMEM_CSTs not
> used inside of initializers, but for PTRMEM_CSTs in initializers we report
> them at UNKNOWN_LOCATION.
> As PTRMEM_CST is a C++ FE tree, I wonder if we couldn't instead of your
> patch or in addition to it do:
> struct GTY(()) ptrmem_cst {
> struct tree_common common;
> tree member;
> + location_t locus;
> };
> #define PTRMEM_CST_LOCATION(NODE) \
> (((ptrmem_cst_t)PTRMEM_CST_CHECK (NODE))->locus)
> and in make_ptrmem_cst set PTRMEM_CST_LOCATION to input_location.
Here is a full so far lightly tested patch that does this,
GXX_TESTSUITE_STDS=98,11,14,17,20,2b make check-g++ \
RUNTESTFLAGS="dg.exp='consteval* srcloc* is-constant-eval* spaceship-synth* constexpr-99287* feat-cxx* lambda-specifiers1*'"
which covers all tests that use consteval keyword in gcc/testsuite/.
Ok for trunk if it passes full bootstrap/regtest?
2021-11-24 Jakub Jelinek <jakub@redhat.com>
PR c++/102753
* cp-tree.h (struct ptrmem_cst): Add locus member.
(PTRMEM_CST_LOCATION): Define.
* tree.c (make_ptrmem_cst): Set PTRMEM_CST_LOCATION to input_location.
* typeck.c (cp_build_addr_expr_1): Don't diagnose taking address of
immediate functions here. Instead when taking their address make
sure the returned ADDR_EXPR has EXPR_LOCATION set.
* pt.c (tsubst_copy): Ensure ADDR_EXPR of immediate function has
EXPR_LOCATION set.
* cp-gimplify.c (cp_fold_r): Diagnose taking address of immediate
functions here. For consteval if don't walk THEN_CLAUSE.
(cp_genericize_r): Don't assert calls to immediate functions must
be source_location_current_p, instead only constant evaluate
calls to source_location_current_p.
* g++.dg/cpp2a/consteval20.C: Add some extra tests.
* g++.dg/cpp2a/consteval23.C: Likewise.
* g++.dg/cpp2a/consteval25.C: New test.
* g++.dg/cpp2a/srcloc20.C: New test.
--- gcc/cp/cp-tree.h.jj 2021-11-24 15:05:23.291928876 +0100
+++ gcc/cp/cp-tree.h 2021-11-24 17:08:19.507806769 +0100
@@ -703,6 +703,7 @@ struct GTY(()) template_parm_index {
struct GTY(()) ptrmem_cst {
struct tree_common common;
tree member;
+ location_t locus;
};
typedef struct ptrmem_cst * ptrmem_cst_t;
@@ -4724,6 +4725,11 @@ more_aggr_init_expr_args_p (const aggr_i
#define PTRMEM_CST_MEMBER(NODE) \
(((ptrmem_cst_t)PTRMEM_CST_CHECK (NODE))->member)
+/* For a pointer-to-member constant `X::Y' this is a location where
+ the address of the member has been taken. */
+#define PTRMEM_CST_LOCATION(NODE) \
+ (((ptrmem_cst_t)PTRMEM_CST_CHECK (NODE))->locus)
+
/* The expression in question for a TYPEOF_TYPE. */
#define TYPEOF_TYPE_EXPR(NODE) (TYPE_VALUES_RAW (TYPEOF_TYPE_CHECK (NODE)))
--- gcc/cp/tree.c.jj 2021-11-24 15:05:23.371927735 +0100
+++ gcc/cp/tree.c 2021-11-24 17:09:05.348164621 +0100
@@ -5167,6 +5167,7 @@ make_ptrmem_cst (tree type, tree member)
tree ptrmem_cst = make_node (PTRMEM_CST);
TREE_TYPE (ptrmem_cst) = type;
PTRMEM_CST_MEMBER (ptrmem_cst) = member;
+ PTRMEM_CST_LOCATION (ptrmem_cst) = input_location;
return ptrmem_cst;
}
--- gcc/cp/typeck.c.jj 2021-11-24 09:54:11.521738651 +0100
+++ gcc/cp/typeck.c 2021-11-24 17:09:43.620628485 +0100
@@ -6780,16 +6780,6 @@ cp_build_addr_expr_1 (tree arg, bool str
return error_mark_node;
}
- if (TREE_CODE (t) == FUNCTION_DECL
- && DECL_IMMEDIATE_FUNCTION_P (t)
- && !in_immediate_context ())
- {
- if (complain & tf_error)
- error_at (loc, "taking address of an immediate function %qD",
- t);
- return error_mark_node;
- }
-
type = build_ptrmem_type (context_for_name_lookup (t),
TREE_TYPE (t));
t = make_ptrmem_cst (type, t);
@@ -6816,15 +6806,6 @@ cp_build_addr_expr_1 (tree arg, bool str
{
tree stripped_arg = tree_strip_any_location_wrapper (arg);
if (TREE_CODE (stripped_arg) == FUNCTION_DECL
- && DECL_IMMEDIATE_FUNCTION_P (stripped_arg)
- && !in_immediate_context ())
- {
- if (complain & tf_error)
- error_at (loc, "taking address of an immediate function %qD",
- stripped_arg);
- return error_mark_node;
- }
- if (TREE_CODE (stripped_arg) == FUNCTION_DECL
&& !mark_used (stripped_arg, complain) && !(complain & tf_error))
return error_mark_node;
val = build_address (arg);
@@ -6865,6 +6846,13 @@ cp_build_addr_expr_1 (tree arg, bool str
complain);
}
+ /* For addresses of immediate functions ensure we have EXPR_LOCATION
+ set for possible later diagnostics. */
+ if (TREE_CODE (val) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (val, 0)) == FUNCTION_DECL
+ && DECL_IMMEDIATE_FUNCTION_P (TREE_OPERAND (val, 0)))
+ SET_EXPR_LOCATION (val, input_location);
+
return val;
}
--- gcc/cp/pt.c.jj 2021-11-24 15:05:23.336928234 +0100
+++ gcc/cp/pt.c 2021-11-24 15:34:29.018014159 +0100
@@ -17012,6 +17012,12 @@ tsubst_copy (tree t, tree args, tsubst_f
r = build1 (code, type, op0);
if (code == ALIGNOF_EXPR)
ALIGNOF_EXPR_STD_P (r) = ALIGNOF_EXPR_STD_P (t);
+ /* For addresses of immediate functions ensure we have EXPR_LOCATION
+ set for possible later diagnostics. */
+ if (code == ADDR_EXPR
+ && TREE_CODE (op0) == FUNCTION_DECL
+ && DECL_IMMEDIATE_FUNCTION_P (op0))
+ SET_EXPR_LOCATION (r, input_location);
return r;
}
--- gcc/cp/cp-gimplify.c.jj 2021-11-19 10:04:54.343314733 +0100
+++ gcc/cp/cp-gimplify.c 2021-11-24 18:39:46.080233582 +0100
@@ -900,8 +900,58 @@ struct cp_genericize_data
static tree
cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data)
{
- tree stmt;
- enum tree_code code;
+ tree stmt = *stmt_p;
+ enum tree_code code = TREE_CODE (stmt);
+
+ switch (code)
+ {
+ case PTRMEM_CST:
+ if (TREE_CODE (PTRMEM_CST_MEMBER (stmt)) == FUNCTION_DECL
+ && DECL_IMMEDIATE_FUNCTION_P (PTRMEM_CST_MEMBER (stmt)))
+ {
+ if (!((hash_set<tree> *) data)->add (stmt))
+ error_at (PTRMEM_CST_LOCATION (stmt),
+ "taking address of an immediate function %qD",
+ PTRMEM_CST_MEMBER (stmt));
+ stmt = *stmt_p = build_zero_cst (TREE_TYPE (stmt));
+ break;
+ }
+ break;
+
+ case ADDR_EXPR:
+ if (TREE_CODE (TREE_OPERAND (stmt, 0)) == FUNCTION_DECL
+ && DECL_IMMEDIATE_FUNCTION_P (TREE_OPERAND (stmt, 0)))
+ {
+ /* Direct calls to std::source_location::current() are
+ only evaluated during genericization, so we need
+ to make an exception for them. But we shouldn't
+ allow those outside of direct calls. */
+ if (source_location_current_p (TREE_OPERAND (stmt, 0))
+ && ((hash_set<tree> *) data)->contains (stmt))
+ break;
+ error_at (EXPR_LOCATION (stmt),
+ "taking address of an immediate function %qD",
+ TREE_OPERAND (stmt, 0));
+ stmt = *stmt_p = build_zero_cst (TREE_TYPE (stmt));
+ break;
+ }
+ break;
+
+ case CALL_EXPR:
+ if (tree fndecl = cp_get_callee_fndecl_nofold (stmt))
+ if (DECL_IMMEDIATE_FUNCTION_P (fndecl)
+ && source_location_current_p (fndecl))
+ {
+ tree fn = cp_get_callee (stmt);
+ STRIP_NOPS (fn);
+ if (TREE_CODE (fn) == ADDR_EXPR)
+ ((hash_set<tree> *) data)->add (fn);
+ }
+ break;
+
+ default:
+ break;
+ }
*stmt_p = stmt = cp_fold (*stmt_p);
@@ -917,12 +967,16 @@ cp_fold_r (tree *stmt_p, int *walk_subtr
}
code = TREE_CODE (stmt);
- if (code == OMP_FOR || code == OMP_SIMD || code == OMP_DISTRIBUTE
- || code == OMP_LOOP || code == OMP_TASKLOOP || code == OACC_LOOP)
+ switch (code)
{
tree x;
int i, n;
-
+ case OMP_FOR:
+ case OMP_SIMD:
+ case OMP_DISTRIBUTE:
+ case OMP_LOOP:
+ case OMP_TASKLOOP:
+ case OACC_LOOP:
cp_walk_tree (&OMP_FOR_BODY (stmt), cp_fold_r, data, NULL);
cp_walk_tree (&OMP_FOR_CLAUSES (stmt), cp_fold_r, data, NULL);
cp_walk_tree (&OMP_FOR_INIT (stmt), cp_fold_r, data, NULL);
@@ -961,6 +1015,22 @@ cp_fold_r (tree *stmt_p, int *walk_subtr
}
cp_walk_tree (&OMP_FOR_PRE_BODY (stmt), cp_fold_r, data, NULL);
*walk_subtrees = 0;
+ return NULL;
+
+ case IF_STMT:
+ if (IF_STMT_CONSTEVAL_P (stmt))
+ {
+ /* Don't walk THEN_CLAUSE (stmt) for consteval if. IF_COND is always
+ boolean_false_node. */
+ cp_walk_tree (&ELSE_CLAUSE (stmt), cp_fold_r, data, NULL);
+ cp_walk_tree (&IF_SCOPE (stmt), cp_fold_r, data, NULL);
+ *walk_subtrees = 0;
+ return NULL;
+ }
+ break;
+
+ default:
+ break;
}
return NULL;
@@ -1477,9 +1547,9 @@ cp_genericize_r (tree *stmt_p, int *walk
}
if (tree fndecl = cp_get_callee_fndecl_nofold (stmt))
- if (DECL_IMMEDIATE_FUNCTION_P (fndecl))
+ if (DECL_IMMEDIATE_FUNCTION_P (fndecl)
+ && source_location_current_p (fndecl))
{
- gcc_assert (source_location_current_p (fndecl));
*stmt_p = cxx_constant_value (stmt);
break;
}
--- gcc/testsuite/g++.dg/cpp2a/consteval20.C.jj 2021-10-27 09:03:07.576043195 +0200
+++ gcc/testsuite/g++.dg/cpp2a/consteval20.C 2021-11-24 16:49:40.481679281 +0100
@@ -10,10 +10,14 @@ constexpr S s;
int
bar ()
{
+ auto c = &S::foo; // { dg-error "taking address of an immediate function" }
+ constexpr auto d = &S::foo; // { dg-error "taking address of an immediate function" }
+ static auto e = &S::foo; // { dg-error "taking address of an immediate function" }
return (s.*&S::foo) (); // { dg-error "taking address of an immediate function" }
}
constexpr auto a = &S::foo; // { dg-error "taking address of an immediate function" }
+auto b = &S::foo; // { dg-error "taking address of an immediate function" }
consteval int
baz ()
--- gcc/testsuite/g++.dg/cpp2a/consteval23.C.jj 2021-10-27 09:03:07.576043195 +0200
+++ gcc/testsuite/g++.dg/cpp2a/consteval23.C 2021-11-24 18:49:34.721877913 +0100
@@ -2,6 +2,7 @@
// { dg-do compile { target c++20 } }
consteval int foo () { return 42; }
+constexpr auto baz (int (*fn) ()) { return fn; }
consteval int
bar (int (*fn) () = foo)
@@ -11,3 +12,6 @@ bar (int (*fn) () = foo)
static_assert (bar () == 42);
static_assert (bar (foo) == 42);
+static_assert (bar (&foo) == 42);
+static_assert (bar (baz (foo)) == 42);
+static_assert (bar (baz (&foo)) == 42);
--- gcc/testsuite/g++.dg/cpp2a/consteval25.C.jj 2021-11-24 18:49:28.321968743 +0100
+++ gcc/testsuite/g++.dg/cpp2a/consteval25.C 2021-11-24 18:50:41.790926102 +0100
@@ -0,0 +1,17 @@
+// PR c++/102753
+// { dg-do compile { target c++20 } }
+// { dg-options "" }
+
+consteval int foo () { return 42; }
+
+consteval int
+bar (int (*fn) ())
+{
+ return fn ();
+}
+
+void
+baz ()
+{
+ static_assert (bar (({ constexpr auto a = 1; foo; })) == 42);
+}
--- gcc/testsuite/g++.dg/cpp2a/srcloc20.C.jj 2021-11-24 18:45:35.810268971 +0100
+++ gcc/testsuite/g++.dg/cpp2a/srcloc20.C 2021-11-24 18:48:01.280204003 +0100
@@ -0,0 +1,44 @@
+// { dg-do compile { target c++20 } }
+
+namespace std {
+ struct source_location {
+ struct __impl {
+ const char *_M_file_name;
+ const char *_M_function_name;
+ unsigned int _M_line, _M_column;
+ };
+ const __impl *__ptr;
+ constexpr source_location () : __ptr (nullptr) {}
+ static consteval source_location
+ current (const void *__p = __builtin_source_location ()) {
+ source_location __ret;
+ __ret.__ptr = static_cast <const __impl *> (__p);
+ return __ret;
+ }
+ constexpr const char *file_name () const {
+ return __ptr ? __ptr->_M_file_name : "";
+ }
+ constexpr const char *function_name () const {
+ return __ptr ? __ptr->_M_function_name : "";
+ }
+ constexpr unsigned line () const {
+ return __ptr ? __ptr->_M_line : 0;
+ }
+ constexpr unsigned column () const {
+ return __ptr ? __ptr->_M_column : 0;
+ }
+ };
+}
+
+using namespace std;
+
+auto a = source_location::current; // { dg-error "taking address of an immediate function" }
+constexpr auto b = &source_location::current; // { dg-error "taking address of an immediate function" }
+
+void
+foo ()
+{
+ auto c = &source_location::current; // { dg-error "taking address of an immediate function" }
+ constexpr auto d = source_location::current; // { dg-error "taking address of an immediate function" }
+ static auto e = source_location::current; // { dg-error "taking address of an immediate function" }
+}
Jakub
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