On 2/4/23 20:41, Jason Merrill wrote:
On 2/4/23 20:08, Patrick Palka wrote:On Sat, 4 Feb 2023, Jason Merrill wrote:On 2/4/23 15:31, Patrick Palka wrote:After r13-5684-g59e0376f607805 the (pruned) callee of a non-dependentCALL_EXPR is a bare FUNCTION_DECL rather than ADDR_EXPR of FUNCTION_DECL.This innocent change revealed that cp_tree_equal doesn't first check dependentness of a CALL_EXPR before treating the callee as a dependent name, which manifests as us incorrectly accepting the first two testcases below and rejecting the third: * In the first testcase, cp_tree_equal incorrectly returns true for the two non-dependent CALL_EXPRs f(0) and f(0) (whose CALL_EXPR_FNare different FUNCTION_DECLs) and so we treat #2 as a redeclarationof #1. * Same issue in the second testcase, for f<int*>() and f<char>(). * In the third testcase, cp_tree_equal incorrectly returns true for f<int>() and f<void(*)(int)>() which causes us to conflate the two dependent specializations A<decltype(f<int>()(U()))> and A<decltype(f<void(*)(int)>()(U()))>, leading to a bogus error. This patch fixes this by making called_fns_equal treat two callees as dependent names only if the CALL_EXPRs in question are dependent.Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK fortrunk/12? Patch generated with -w to ignore noisy whitespace changes. PR c++/107461 gcc/cp/ChangeLog: * pt.cc (iterative_hash_template_arg) <case CALL_EXPR>: Treat the callee as a dependent name only if the CALL_EXPR is dependent. * tree.cc (called_fns_equal): Take two CALL_EXPRs instead of CALL_EXPR_FNs thereof. As above. (cp_tree_equal) <case CALL_EXPR>: Adjust call to called_fns_equal. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/overload5.C: New test. * g++.dg/cpp0x/overload5a.C: New test. * g++.dg/cpp0x/overload6.C: New test. --- gcc/cp/pt.cc | 1 +gcc/cp/tree.cc | 33 ++++++++++++++-----------gcc/testsuite/g++.dg/cpp0x/overload5.C | 12 +++++++++ gcc/testsuite/g++.dg/cpp0x/overload5a.C | 10 ++++++++ gcc/testsuite/g++.dg/cpp0x/overload6.C | 16 ++++++++++++ 5 files changed, 58 insertions(+), 14 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5.C create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5a.C create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload6.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 255332dc0c1..c9360240cd2 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc@@ -1841,6 +1841,7 @@ iterative_hash_template_arg (tree arg, hashval_t val)case CALL_EXPR: { tree fn = CALL_EXPR_FN (arg); + if (TREE_TYPE (arg) == NULL_TREE)How about changing dependent_name to take the CALL_EXPR rather than theCALL_EXPR_FN? That would mean some changes to write_expression to move the dependent_name handling into the CALL_EXPR handling, but that doesn't seemlike a bad thing. Other callers seem like a trivial change.Indeed changing dependent_name seems best, but I'm worried about such a refactoring to write_expression causing unintended mangling changes at this stage. Because it seems the CALL_EXPR case of write_expression isn't the user of the dependent_name branch of write_expression, at least according to the following patch which causes us to ICE on mangle{37,57,58,76}.C:Yeah, I tried the same thing. Maybe for GCC 13 better to add a new function rather than change the current one.
mangle76 seems like a bug where we're producing (and testing for) the wrong mangling -- mangling (*this). that doesn't exist in the source. clang gets it right.
mangle5{7,8} has the right mangling, we're just using dependent_name to mangle function names that aren't dependent names (because they're template arguments in both cases, and qualified in the latter).
diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc index f2cda3be2cf..700857f8f3c 100644 --- a/gcc/cp/mangle.cc +++ b/gcc/cp/mangle.cc @@ -3450,6 +3450,7 @@ write_expression (tree expr) } else if (dependent_name (expr)) { + gcc_unreachable (); tree name = dependent_name (expr); if (IDENTIFIER_ANY_OP_P (name)) { @@ -3554,7 +3555,19 @@ write_expression (tree expr) && type_dependent_expression_p_push (expr)) fn = OVL_NAME (fn); - write_expression (fn); + if (tree name = dependent_name (fn)) + { + if (IDENTIFIER_ANY_OP_P (name)) + { + if (abi_version_at_least (16)) + write_string ("on"); + if (abi_warn_or_compat_version_crosses (16)) + G.need_abi_warning = 1; + } + write_unqualified_id (name); + } + else + write_expression (fn); } for (i = 0; i < call_expr_nargs (expr); ++i) And since the CALL_EXPR case of write_expression looks through an ADDR_EXPR callee before recursing, IIUC the refactoring would need to make dependent_name look through an ADDR_EXPR callee as well, which seems like a desirable/correct change but I'm worried that might have unintended consequences as well.if (tree name = dependent_name (fn)) { if (TREE_CODE (fn) == TEMPLATE_ID_EXPR) diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc index c1da868732b..3a57e71b76e 100644 --- a/gcc/cp/tree.cc +++ b/gcc/cp/tree.cc @@ -3870,16 +3870,21 @@ decl_internal_context_p (const_tree decl) return !TREE_PUBLIC (decl); }-/* Subroutine of cp_tree_equal: t1 and t2 are the CALL_EXPR_FNs of two- CALL_EXPRS. Return whether they are equivalent. */ +/* Subroutine of cp_tree_equal: t1 and t2 are two CALL_EXPRs. + Return whether their CALL_EXPR_FNs are equivalent. */ static bool called_fns_equal (tree t1, tree t2) +{ + tree fn1 = CALL_EXPR_FN (t1); + tree fn2 = CALL_EXPR_FN (t2); + if (TREE_TYPE (t1) == NULL_TREE + && TREE_TYPE (t2) == NULL_TREE) {/* Core 1321: dependent names are equivalent even if the overloadsets are different. But do compare explicit template arguments. */ - tree name1 = dependent_name (t1); - tree name2 = dependent_name (t2); + tree name1 = dependent_name (fn1); + tree name2 = dependent_name (fn2); if (name1 || name2) { tree targs1 = NULL_TREE, targs2 = NULL_TREE; @@ -3891,19 +3896,19 @@ called_fns_equal (tree t1, tree t2) of whether the function was named with a qualified- or unqualified-id.Until that's fixed, check that we aren't looking at overload setsfrom different scopes. */ - if (is_overloaded_fn (t1) && is_overloaded_fn (t2) - && (DECL_CONTEXT (get_first_fn (t1)) - != DECL_CONTEXT (get_first_fn (t2)))) + if (is_overloaded_fn (fn1) && is_overloaded_fn (fn2) + && (DECL_CONTEXT (get_first_fn (fn1)) + != DECL_CONTEXT (get_first_fn (fn2)))) return false; - if (TREE_CODE (t1) == TEMPLATE_ID_EXPR) - targs1 = TREE_OPERAND (t1, 1); - if (TREE_CODE (t2) == TEMPLATE_ID_EXPR) - targs2 = TREE_OPERAND (t2, 1); + if (TREE_CODE (fn1) == TEMPLATE_ID_EXPR) + targs1 = TREE_OPERAND (fn1, 1); + if (TREE_CODE (fn2) == TEMPLATE_ID_EXPR) + targs2 = TREE_OPERAND (fn2, 1); return cp_tree_equal (targs1, targs2); } - else - return cp_tree_equal (t1, t2); + } + return cp_tree_equal (fn1, fn2); } bool comparing_override_contracts; @@ -4037,7 +4042,7 @@ cp_tree_equal (tree t1, tree t2) if (KOENIG_LOOKUP_P (t1) != KOENIG_LOOKUP_P (t2)) return false; - if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2))) + if (!called_fns_equal (t1, t2)) return false; call_expr_arg_iterator iter1, iter2; diff --git a/gcc/testsuite/g++.dg/cpp0x/overload5.C b/gcc/testsuite/g++.dg/cpp0x/overload5.C new file mode 100644 index 00000000000..e05b1594f51 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/overload5.C @@ -0,0 +1,12 @@ +// PR c++/107461 +// { dg-do compile { target c++11 } } + +int f(...); +template<class T> decltype(T() + f(0)) g(); // #1 + +char f(int); +template<class T> decltype(T() + f(0)) g(); // #2, distinct from #1 + +int main() { + g<int>(); // { dg-error "ambiguous" } +} diff --git a/gcc/testsuite/g++.dg/cpp0x/overload5a.C b/gcc/testsuite/g++.dg/cpp0x/overload5a.C new file mode 100644 index 00000000000..037114f199c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/overload5a.C @@ -0,0 +1,10 @@ +// PR c++/107461 +// { dg-do compile { target c++11 } } + +template<class T> T f(); +template<class T> decltype(T() + f<int*>()) g(); // #1+template<class T> decltype(T() + f<char>()) g(); // #2, distinct from #1+ +int main() { + g<int>(); // { dg-error "ambiguous" } +} diff --git a/gcc/testsuite/g++.dg/cpp0x/overload6.C b/gcc/testsuite/g++.dg/cpp0x/overload6.C new file mode 100644 index 00000000000..1fbee0501de --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/overload6.C @@ -0,0 +1,16 @@ +// PR c++/107461 +// { dg-do compile { target c++11 } } + +template<class T> T f(); + +template<class> struct A { }; + +template<class T> struct B { + template<class U, class = A<decltype(f<T>()(U()))>> + static void g(U); +}; + +int main() { + B<int> b; + B<void(*)(int)>::g(0); // { dg-bogus "no match" } +}