From a7201a085cc30f89944931d8fb1d7936f02a169f Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Wed, 29 Apr 2020 09:04:58 -0400 Subject: [PATCH] c++: Nondeterministic concepts diagnostics [PR94830] This patch makes the order in which template parameters appear in the TREE_LIST returned by find_template_parameters deterministic between runs. The current nondeterminism is semantically harmless, but it has the undesirable effect of causing some concepts diagnostics which print a constraint's parameter mapping via pp_cxx_parameter_mapping to also be nondeterministic, as in the testcases below. gcc/cp/ChangeLog: PR c++/94830 * pt.c (find_template_parameter_info::parm_list): New field. (keep_template_parm): Use the new field to build up the parameter list here instead of ... (find_template_parameters): ... here. Return ftpi.parm_list. gcc/testsuite/ChangeLog: PR c++/94830 * g++.dg/concepts/diagnostics12.C: Clarify the dg-message now that the corresponding diagnostic is deterministic. * g++.dg/concepts/diagnostics13.C: New test. --- gcc/cp/ChangeLog | 8 ++++++++ gcc/cp/pt.c | 13 ++++++------- gcc/testsuite/ChangeLog | 7 +++++++ gcc/testsuite/g++.dg/concepts/diagnostic12.C | 2 +- gcc/testsuite/g++.dg/concepts/diagnostic13.C | 14 ++++++++++++++ 5 files changed, 36 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/g++.dg/concepts/diagnostic13.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 41db16e782f..cbedbabe3a6 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,11 @@ +2020-04-29 Patrick Palka + + PR c++/94830 + * pt.c (find_template_parameter_info::parm_list): New field. + (keep_template_parm): Use the new field to build up the + parameter list here instead of ... + (find_template_parameters): ... here. Return ftpi.parm_list. + 2020-04-29 Jakub Jelinek PR target/94707 diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index ba22d9ec538..d28585efd17 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -10439,12 +10439,14 @@ for_each_template_parm (tree t, tree_fn_t fn, void* data, struct find_template_parameter_info { explicit find_template_parameter_info (tree ctx_parms) - : ctx_parms (ctx_parms), + : parm_list (NULL_TREE), + ctx_parms (ctx_parms), max_depth (TMPL_PARMS_DEPTH (ctx_parms)) {} hash_set visited; hash_set parms; + tree parm_list; tree ctx_parms; int max_depth; }; @@ -10476,7 +10478,8 @@ keep_template_parm (tree t, void* data) T and const T. Adjust types to their unqualified versions. */ if (TYPE_P (t)) t = TYPE_MAIN_VARIANT (t); - ftpi->parms.add (t); + if (!ftpi->parms.add (t)) + ftpi->parm_list = tree_cons (NULL_TREE, t, ftpi->parm_list); return 0; } @@ -10587,11 +10590,7 @@ find_template_parameters (tree t, tree ctx_parms) find_template_parameter_info ftpi (ctx_parms); for_each_template_parm (t, keep_template_parm, &ftpi, &ftpi.visited, /*include_nondeduced*/true, any_template_parm_r); - tree list = NULL_TREE; - for (hash_set::iterator iter = ftpi.parms.begin(); - iter != ftpi.parms.end(); ++iter) - list = tree_cons (NULL_TREE, *iter, list); - return list; + return ftpi.parm_list; } /* Returns true if T depends on any template parameter. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index b635ce1939d..0fce8fba0a4 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2020-04-29 Patrick Palka + + PR c++/94830 + * g++.dg/concepts/diagnostics12.C: Clarify the dg-message now + that the corresponding diagnostic is deterministic. + * g++.dg/concepts/diagnostics13.C: New test. + 2020-04-29 H.J. Lu PR target/93654 diff --git a/gcc/testsuite/g++.dg/concepts/diagnostic12.C b/gcc/testsuite/g++.dg/concepts/diagnostic12.C index a757342f754..548ba9c1b3d 100644 --- a/gcc/testsuite/g++.dg/concepts/diagnostic12.C +++ b/gcc/testsuite/g++.dg/concepts/diagnostic12.C @@ -3,7 +3,7 @@ template concept c1 = requires (T t, Args... args) { *t; }; -// { dg-message "in requirements with .T t., .Args ... args. .with.* Args = \{\}" "" { target *-*-* } .-1 } +// { dg-message "in requirements with .T t., .Args ... args. .with Args = \{\}; T = int" "" { target *-*-* } .-1 } static_assert(c1); // { dg-error "failed" } diff --git a/gcc/testsuite/g++.dg/concepts/diagnostic13.C b/gcc/testsuite/g++.dg/concepts/diagnostic13.C new file mode 100644 index 00000000000..accd8a6d2bd --- /dev/null +++ b/gcc/testsuite/g++.dg/concepts/diagnostic13.C @@ -0,0 +1,14 @@ +// PR c++/94830 +// { dg-do compile { target concepts } } + +template + concept c = __is_same(T, R); // { dg-message "with T = int; R = char" } + +template + requires c +void foo() { } + +void bar() +{ + foo(); // { dg-error "unsatisfied constraints" } +} -- 2.30.2