From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by sourceware.org (Postfix) with ESMTPS id 901BB3858D32; Thu, 7 Jul 2022 15:53:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 901BB3858D32 Received: from localhost.intra.ispras.ru (unknown [10.10.3.121]) by mail.ispras.ru (Postfix) with ESMTP id 7294E40755E1; Thu, 7 Jul 2022 15:53:42 +0000 (UTC) From: Alexander Monakov To: gcc-patches@gcc.gnu.org Cc: Jan Hubicka , Artem Klimov , Alexander Monakov Subject: [PATCH v2] ipa-visibility: Optimize TLS access [PR99619] Date: Thu, 7 Jul 2022 18:53:41 +0300 Message-Id: <20220707155341.5884-1-amonakov@ispras.ru> X-Mailer: git-send-email 2.32.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-8.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Jul 2022 15:53:51 -0000 From: Artem Klimov Fix PR99619, which asks to optimize TLS model based on visibility. The fix is implemented as an IPA optimization: this allows to take optimized visibility status into account (as well as avoid modifying all language frontends). 2022-04-17 Artem Klimov gcc/ChangeLog: * ipa-visibility.cc (function_and_variable_visibility): Promote TLS access model afer visibility optimizations. * varasm.cc (have_optimized_refs): New helper. (optimize_dyn_tls_for_decl_p): New helper. Use it ... (decl_default_tls_model): ... here in place of 'optimize' check. gcc/testsuite/ChangeLog: * gcc.dg/tls/vis-attr-gd.c: New test. * gcc.dg/tls/vis-attr-hidden-gd.c: New test. * gcc.dg/tls/vis-attr-hidden.c: New test. * gcc.dg/tls/vis-flag-hidden-gd.c: New test. * gcc.dg/tls/vis-flag-hidden.c: New test. * gcc.dg/tls/vis-pragma-hidden-gd.c: New test. * gcc.dg/tls/vis-pragma-hidden.c: New test. Co-Authored-By: Alexander Monakov Signed-off-by: Artem Klimov --- v2: run the new loop in ipa-visibility only in the whole-program IPA pass; in decl_default_tls_model, check if any referring function is optimized when 'optimize == 0' (when running in LTO mode) Note for reviewers: I noticed there's a place which tries to avoid TLS promotion, but the comment seems wrong and I could not find a testcase. I'd suggest we remove it. The compiler can only promote general-dynamic to local-dynamic and initial-exec to local-exec. The comment refers to promoting x-dynamic to y-exec, but that cannot happen AFAICT: https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=8e1ba78f1b8eedd6c65c6f0e6d6d09a801de5d3d gcc/ipa-visibility.cc | 19 +++++++++++ gcc/testsuite/gcc.dg/tls/vis-attr-gd.c | 12 +++++++ gcc/testsuite/gcc.dg/tls/vis-attr-hidden-gd.c | 13 ++++++++ gcc/testsuite/gcc.dg/tls/vis-attr-hidden.c | 12 +++++++ gcc/testsuite/gcc.dg/tls/vis-flag-hidden-gd.c | 13 ++++++++ gcc/testsuite/gcc.dg/tls/vis-flag-hidden.c | 12 +++++++ .../gcc.dg/tls/vis-pragma-hidden-gd.c | 17 ++++++++++ gcc/testsuite/gcc.dg/tls/vis-pragma-hidden.c | 16 ++++++++++ gcc/varasm.cc | 32 ++++++++++++++++++- 9 files changed, 145 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/tls/vis-attr-gd.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-attr-hidden-gd.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-attr-hidden.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-flag-hidden-gd.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-flag-hidden.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-pragma-hidden-gd.c create mode 100644 gcc/testsuite/gcc.dg/tls/vis-pragma-hidden.c diff --git a/gcc/ipa-visibility.cc b/gcc/ipa-visibility.cc index 8a27e7bcd..3ed2b7cf6 100644 --- a/gcc/ipa-visibility.cc +++ b/gcc/ipa-visibility.cc @@ -873,6 +873,25 @@ function_and_variable_visibility (bool whole_program) } } + if (symtab->state >= IPA_SSA) + { + FOR_EACH_VARIABLE (vnode) + { + tree decl = vnode->decl; + + /* Upgrade TLS access model based on optimized visibility status, + unless it was specified explicitly or no references remain. */ + if (DECL_THREAD_LOCAL_P (decl) + && !lookup_attribute ("tls_model", DECL_ATTRIBUTES (decl)) + && vnode->ref_list.referring.length ()) + { + enum tls_model new_model = decl_default_tls_model (decl); + gcc_checking_assert (new_model >= decl_tls_model (decl)); + set_decl_tls_model (decl, new_model); + } + } + } + if (dump_file) { fprintf (dump_file, "\nMarking local functions:"); diff --git a/gcc/varasm.cc b/gcc/varasm.cc index 4db8506b1..de149e82c 100644 --- a/gcc/varasm.cc +++ b/gcc/varasm.cc @@ -6679,6 +6679,36 @@ init_varasm_once (void) #endif } +/* Determine whether SYMBOL is used in any optimized function. */ + +static bool +have_optimized_refs (struct symtab_node *symbol) +{ + struct ipa_ref *ref; + + for (int i = 0; symbol->iterate_referring (i, ref); i++) + { + cgraph_node *cnode = dyn_cast (ref->referring); + + if (cnode && opt_for_fn (cnode->decl, optimize)) + return true; + } + + return false; +} + +/* Check if promoting general-dynamic TLS access model to local-dynamic is + desirable for DECL. */ + +static bool +optimize_dyn_tls_for_decl_p (const_tree decl) +{ + if (optimize) + return true; + return symtab->state >= IPA && have_optimized_refs (symtab_node::get (decl)); +} + + enum tls_model decl_default_tls_model (const_tree decl) { @@ -6696,7 +6726,7 @@ decl_default_tls_model (const_tree decl) /* Local dynamic is inefficient when we're not combining the parts of the address. */ - else if (optimize && is_local) + else if (is_local && optimize_dyn_tls_for_decl_p (decl)) kind = TLS_MODEL_LOCAL_DYNAMIC; else kind = TLS_MODEL_GLOBAL_DYNAMIC; diff --git a/gcc/testsuite/gcc.dg/tls/vis-attr-gd.c b/gcc/testsuite/gcc.dg/tls/vis-attr-gd.c new file mode 100644 index 000000000..89a248a80 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-attr-gd.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program" } */ + +// tls_model should be global-dynamic due to explicitly specified attribute +__attribute__((tls_model("global-dynamic"))) +__thread int x; + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-global-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-attr-hidden-gd.c b/gcc/testsuite/gcc.dg/tls/vis-attr-hidden-gd.c new file mode 100644 index 000000000..e32565588 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-attr-hidden-gd.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program" } */ + +// tls_model should be global-dynamic due to explicitly specified attribute +__attribute__((visibility("hidden"))) +__attribute__((tls_model("global-dynamic"))) +__thread int x; + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-global-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-attr-hidden.c b/gcc/testsuite/gcc.dg/tls/vis-attr-hidden.c new file mode 100644 index 000000000..0d43fc565 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-attr-hidden.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program" } */ + +//tls_model should be local-dynamic due to visibility("hidden") +__attribute__((visibility("hidden"))) +__thread int x; + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-local-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-flag-hidden-gd.c b/gcc/testsuite/gcc.dg/tls/vis-flag-hidden-gd.c new file mode 100644 index 000000000..cad41e0c8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-flag-hidden-gd.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program -fvisibility=hidden" } */ + + +// tls_model should be global-dynamic due to explicitly specified attribute +__attribute__((tls_model("global-dynamic"))) +__thread int x; + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-global-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-flag-hidden.c b/gcc/testsuite/gcc.dg/tls/vis-flag-hidden.c new file mode 100644 index 000000000..a15df092d --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-flag-hidden.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program -fvisibility=hidden" } */ + + +// tls_model should be local-dynamic due to -fvisibility=hidden +__thread int x; + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-local-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden-gd.c b/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden-gd.c new file mode 100644 index 000000000..3b3598134 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden-gd.c @@ -0,0 +1,17 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program" } */ + + +#pragma GCC visibility push(hidden) + +// tls_model should be global-dynamic due to explicitly specified attribute +__attribute__((tls_model("global-dynamic"))) +__thread int x; + +#pragma GCC visibility pop + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-global-dynamic" "whole-program" } } */ diff --git a/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden.c b/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden.c new file mode 100644 index 000000000..1be976442 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/vis-pragma-hidden.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target fpic } */ +/* { dg-require-effective-target tls } */ +/* { dg-options "-O2 -fPIC -fdump-ipa-whole-program" } */ + + +#pragma GCC visibility push(hidden) + +// tls_model should be local-dynamic due to a pragma +__thread int x; + +#pragma GCC visibility pop + +void reference() { x++; } + +/* { dg-final { scan-ipa-dump "Varpool flags: tls-local-dynamic" "whole-program" } } */ -- 2.35.1