On 3/18/23 11:09, Jakub Jelinek wrote:
On Sat, Mar 18, 2023 at 01:54:58PM +0100, Jakub Jelinek via Gcc-patches wrote:The patch is mostly about DECL_EXTERNAL cases, the others are supposedly handled by the var_definition_p code there (or at least I assumed; testcases certainly test only DECL_EXTERNAL). I guess it could be done in cp_finish_decl, maybe better next to the /* A reference will be modified here, as it is initialized. */ if (! DECL_EXTERNAL (decl) && TREE_READONLY (decl) && TYPE_REF_P (type)) { was_readonly = 1; TREE_READONLY (decl) = 0; } spot, but we'd need to export the decl2.cc helpers for it, because not all DECL_THREAD_LOCAL_P vars need to be treated that way. if (VAR_P (decl) && CP_DECL_THREAD_LOCAL_P (decl) && var_needs_tls_wrapper (decl) && (!DECL_EXTERNAL (decl) || flag_extern_tls_init)) TREE_READONLY (decl) = 0; where var_needs_tls_wrapper would need to be exported from decl2.cc. Though, var_needs_tls_wrapper -> var_defined_without_dynamic_init needs DECL_NONTRIVIALLY_INITIALIZED_P/DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P, so perhaps that is accurate only closer to the end of cp_finish_decl?Here it is in patch form, tested so far on tls.exp: 2023-03-18 Jakub Jelinek <ja...@redhat.com> PR c++/109164 * cp-tree.h (var_needs_tls_wrapper): Declare. * decl2.cc (var_needs_tls_wrapper): No longer static. * decl.cc (cp_finish_decl): Clear TREE_READONLY on TLS variables for which a TLS wrapper will be needed. * g++.dg/tls/thread_local13.C: New test. * g++.dg/tls/thread_local13-aux.cc: New file. * g++.dg/tls/thread_local14.C: New test. * g++.dg/tls/thread_local14-aux.cc: New file. --- gcc/cp/cp-tree.h.jj 2023-03-17 08:37:07.542937058 +0100 +++ gcc/cp/cp-tree.h 2023-03-18 16:02:46.771230806 +0100 @@ -6989,6 +6989,7 @@ extern void copy_linkage (tree, tree); extern tree get_guard (tree); extern tree get_guard_cond (tree, bool); extern tree set_guard (tree); +extern bool var_needs_tls_wrapper (tree); extern tree maybe_get_tls_wrapper_call (tree); extern void mark_needed (tree); extern bool decl_needed_p (tree); --- gcc/cp/decl2.cc.jj 2023-03-17 16:09:01.749244271 +0100 +++ gcc/cp/decl2.cc 2023-03-18 15:48:31.340642324 +0100 @@ -3623,7 +3623,7 @@ var_defined_without_dynamic_init (tree v /* Returns true iff VAR is a variable that needs uses to be wrapped for possible dynamic initialization. */-static bool+bool var_needs_tls_wrapper (tree var) { return (!error_operand_p (var) --- gcc/cp/decl.cc.jj 2023-03-18 15:47:32.198500421 +0100 +++ gcc/cp/decl.cc 2023-03-18 16:00:04.565584266 +0100 @@ -8706,6 +8706,18 @@ cp_finish_decl (tree decl, tree init, bo if (!decl_maybe_constant_destruction (decl, type)) TREE_READONLY (decl) = 0; } + else if (VAR_P (decl) + && CP_DECL_THREAD_LOCAL_P (decl) + && (!DECL_EXTERNAL (decl) || flag_extern_tls_init)
Hmm, I wonder why we don't check the above line in var_needs_tls_wrapper? But the patch is OK.
+ && (was_readonly || TREE_READONLY (decl)) + && var_needs_tls_wrapper (decl)) + { + /* TLS variables need dynamic initialization by the TLS wrapper + function, we don't want to hoist accesses to it before the + wrapper. */ + was_readonly = 0; + TREE_READONLY (decl) = 0; + }make_rtl_for_nonlocal_decl (decl, init, asmspec); --- gcc/testsuite/g++.dg/tls/thread_local13.C.jj 2023-03-18 15:47:50.934228583 +0100+++ gcc/testsuite/g++.dg/tls/thread_local13.C 2023-03-18 15:47:50.934228583 +0100 @@ -0,0 +1,21 @@ +// PR c++/109164 +// { dg-do run { target c++11 } } +// { dg-options "-O2" } +// { dg-add-options tls } +// { dg-require-effective-target tls_runtime } +// { dg-additional-sources "thread_local13-aux.cc" } + +struct S { virtual void foo (); int s; }; +extern thread_local S &t; +bool bar (); + +bool +baz () +{ + while (1) + { + t.foo (); + if (!bar ()) + return false; + } +} --- gcc/testsuite/g++.dg/tls/thread_local13-aux.cc.jj 2023-03-18 15:47:50.934228583 +0100 +++ gcc/testsuite/g++.dg/tls/thread_local13-aux.cc 2023-03-18 15:47:50.934228583 +0100 @@ -0,0 +1,35 @@ +// PR c++/109164 + +struct S { virtual void foo (); int s; }; +extern bool baz (); + +void +S::foo () +{ + if (s != 42) + __builtin_abort (); +} + +S s; + +S & +qux () +{ + s.s = 42; + return s; +} + +thread_local S &t = qux (); + +bool +bar () +{ + return false; +} + +int +main () +{ + if (baz ()) + __builtin_abort (); +} --- gcc/testsuite/g++.dg/tls/thread_local14.C.jj 2023-03-18 15:47:50.934228583 +0100 +++ gcc/testsuite/g++.dg/tls/thread_local14.C 2023-03-18 15:47:50.934228583 +0100 @@ -0,0 +1,19 @@ +// PR c++/109164 +// { dg-do run { target c++11 } } +// { dg-options "-O2" } +// { dg-add-options tls } +// { dg-require-effective-target tls_runtime } +// { dg-additional-sources "thread_local14-aux.cc" } + +extern thread_local const int t; +bool bar (int); + +bool +baz () +{ + while (1) + { + if (!bar (t)) + return false; + } +} --- gcc/testsuite/g++.dg/tls/thread_local14-aux.cc.jj 2023-03-18 15:47:50.934228583 +0100 +++ gcc/testsuite/g++.dg/tls/thread_local14-aux.cc 2023-03-18 15:47:50.934228583 +0100 @@ -0,0 +1,26 @@ +// PR c++/109164 + +extern bool baz (); + +int +qux () +{ + return 42; +} + +extern thread_local const int t = qux (); + +bool +bar (int x) +{ + if (x != 42) + __builtin_abort (); + return false; +} + +int +main () +{ + if (baz ()) + __builtin_abort (); +} Jakub
