From 24d21a0bc07ee2c9b041504956834be3bba7e746 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 4 Apr 2018 03:40:29 +0000 Subject: [PATCH] [PR c++/84943] mark function as used when taking its address fn[0]() ICEd because we would fold the INDIRECT_REF used for the array indexing while building the address for the call, after not finding the decl hiding there at first. But the decl would be exposed by the folding, and then lower layers would complain we had the decl, after all, but it wasn't one of the artificial or special functions that could be called without being marked as used. This patch arranges for a FUNCTION_DECL to be marked as used when taking its address, just like we already did when taking the address of a static function to call it as a member function (i.e. using the obj.fn() notation). However, we shouldn't mark functions as used when just performing overload resolution, lest we might instantiate templates we shouldn't, as in g++.dg/overload/template1.C, so we adjust mark_used to return early when testing conversions. for gcc/cp/ChangeLog PR c++/84943 * typeck.c (cp_build_addr_expr_1): Mark FUNCTION_DECL as used. * decl2.c (mark_used): Return without effects if tf_conv. for gcc/testsuite/ChangeLog PR c++/84943 * g++.dg/pr84943.C: New. * g++.dg/pr84943-2.C: New. From-SVN: r259067 --- gcc/cp/ChangeLog | 7 ++++ gcc/cp/decl2.c | 6 +++ gcc/cp/typeck.c | 3 ++ gcc/testsuite/ChangeLog | 6 +++ gcc/testsuite/g++.dg/pr84943-2.C | 64 ++++++++++++++++++++++++++++++++ gcc/testsuite/g++.dg/pr84943.C | 8 ++++ 6 files changed, 94 insertions(+) create mode 100644 gcc/testsuite/g++.dg/pr84943-2.C create mode 100644 gcc/testsuite/g++.dg/pr84943.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 4a9f9995d24..46f05c8661e 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2018-04-04 Alexandre Oliva + + PR c++/84943 + * typeck.c (cp_build_addr_expr_1): Mark FUNCTION_DECL as + used. + * decl2.c (mark_used): Return without effects if tf_conv. + 2018-04-03 Jason Merrill PR c++/85092 - C++17 ICE with unused list constructor. diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c index fa753749e1a..6ae6cef78dd 100644 --- a/gcc/cp/decl2.c +++ b/gcc/cp/decl2.c @@ -5201,6 +5201,12 @@ maybe_instantiate_decl (tree decl) bool mark_used (tree decl, tsubst_flags_t complain) { + /* If we're just testing conversions or resolving overloads, we + don't want any permanent effects like forcing functions to be + output or instantiating templates. */ + if ((complain & tf_conv)) + return true; + /* If DECL is a BASELINK for a single function, then treat it just like the DECL for the function. Otherwise, if the BASELINK is for an overloaded function, we don't know which function was diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c index e33f2c34c7f..2b7a771bbeb 100644 --- a/gcc/cp/typeck.c +++ b/gcc/cp/typeck.c @@ -5971,6 +5971,9 @@ cp_build_addr_expr_1 (tree arg, bool strict_lvalue, tsubst_flags_t complain) so we can just form an ADDR_EXPR with the correct type. */ if (processing_template_decl || TREE_CODE (arg) != COMPONENT_REF) { + if (TREE_CODE (arg) == FUNCTION_DECL + && !mark_used (arg, complain) && !(complain & tf_error)) + return error_mark_node; val = build_address (arg); if (TREE_CODE (arg) == OFFSET_REF) PTRMEM_OK_P (val) = PTRMEM_OK_P (arg); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index de14495bf9a..95cd7c8392d 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2018-04-04 Alexandre Oliva + + PR c++/84943 + * g++.dg/pr84943.C: New. + * g++.dg/pr84943-2.C: New. + 2018-04-03 Jakub Jelinek PR rtl-optimization/85167 diff --git a/gcc/testsuite/g++.dg/pr84943-2.C b/gcc/testsuite/g++.dg/pr84943-2.C new file mode 100644 index 00000000000..d1ef012b915 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr84943-2.C @@ -0,0 +1,64 @@ +// { dg-do run } + +// Avoid -pedantic-error default +// { dg-options "" } + +// Make sure the functions referenced by various forms of +// address-taking are marked as used and compiled in. + +static void ac() {} +void a() { + ac[0](); // { dg-warning "arithmetic" } +} + +static void bc() {} +void b() { + (&*&*&*&bc)(); +} + +template U cc() {} +void (*c())() { + return cc; +} + +template +struct x { + void a(int); + template static U a(x*) {} + static void a(long) {} + static void a(void *) {} + static void a() { + void (*p0)(void*) = x().a; + p0(0); + void (*p1)(long) = a; + p1(0); + void (*p2)() = a; + p2(); + void (*p3)(x*) = a; + p3(0); + } +}; + +struct z { + void a(int); + template static U a(z*) {} + static void a(long) {} + static void a(void *) {} + static void a() { + void (*p0)(void*) = z().a; + p0(0); + void (*p1)(long) = a; + p1(0); + void (*p2)() = a; + p2(); + void (*p3)(z*) = a; + p3(0); + } +}; + +int main(int argc, char *argv[]) { + if (argc > 1) { + x().a(); + z().a(); + } +} diff --git a/gcc/testsuite/g++.dg/pr84943.C b/gcc/testsuite/g++.dg/pr84943.C new file mode 100644 index 00000000000..36f75a16411 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr84943.C @@ -0,0 +1,8 @@ +// { dg-do compile } + +// Avoid -pedantic-error default +// { dg-options "" } + +void a() { + a[0](); // { dg-warning "arithmetic" } +} -- 2.30.2