From 9585381acd709663a97f2c7b208a674a3ed4f4a9 Mon Sep 17 00:00:00 2001 From: Torvald Riegel Date: Mon, 18 Jan 2016 20:09:55 +0000 Subject: [PATCH] libstdc++: Fix usage of __GXX_WEAK__ in TM TS support. * include/bits/c++config (_GLIBCXX_USE_WEAK_REF): New. (_GLIBCXX_TXN_SAFE, _GLIBCXX_TXN_SAFE_DYN): Use _GLIBCXX_USE_WEAK_REF and move after its definition. * config/os/aix/os_defines.h (_GLIBCXX_USE_WEAK_REF): Override. * src/c++11/cow-stdexcept.cc: Use _GLIBCXX_USE_WEAK_REF instead of __GXX_WEAK__, and only provide transactional clones if _GLIBCXX_USE_WEAK_REF is true. Don't provide stubs of libitm functions. From-SVN: r232539 --- libstdc++-v3/ChangeLog | 11 ++++++++++ libstdc++-v3/config/os/aix/os_defines.h | 3 +++ libstdc++-v3/include/bits/c++config | 36 ++++++++++++++++++++------------- libstdc++-v3/src/c++11/cow-stdexcept.cc | 23 +++++++++------------ 4 files changed, 45 insertions(+), 28 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 0b7ca1b..d68f5a5 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,14 @@ +2016-01-18 Torvald Riegel + + * include/bits/c++config (_GLIBCXX_USE_WEAK_REF): New. + (_GLIBCXX_TXN_SAFE, _GLIBCXX_TXN_SAFE_DYN): Use _GLIBCXX_USE_WEAK_REF + and move after its definition. + * config/os/aix/os_defines.h (_GLIBCXX_USE_WEAK_REF): Override. + * src/c++11/cow-stdexcept.cc: Use _GLIBCXX_USE_WEAK_REF instead of + __GXX_WEAK__, and only provide transactional clones if + _GLIBCXX_USE_WEAK_REF is true. Don't provide stubs of libitm + functions. + 2016-01-18 Jonathan Wakely PR libstdc++/60637 diff --git a/libstdc++-v3/config/os/aix/os_defines.h b/libstdc++-v3/config/os/aix/os_defines.h index d895471..0949446 100644 --- a/libstdc++-v3/config/os/aix/os_defines.h +++ b/libstdc++-v3/config/os/aix/os_defines.h @@ -48,4 +48,7 @@ #define __COMPATMATH__ #endif +// No support for referencing weak symbols without a definition. +#define _GLIBCXX_USE_WEAK_REF 0 + #endif diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index 387a7bb..57024e4 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -483,20 +483,6 @@ namespace std #define _GLIBCXX_USE_ALLOCATOR_NEW -// Conditionally enable annotations for the Transactional Memory TS on C++11. -// Most of the following conditions are due to limitations in the current -// implementation. -#if __cplusplus >= 201103L && _GLIBCXX_USE_CXX11_ABI \ - && _GLIBCXX_USE_DUAL_ABI && __cpp_transactional_memory >= 201505L \ - && !_GLIBCXX_FULLY_DYNAMIC_STRING && __GXX_WEAK__ \ - && _GLIBCXX_USE_ALLOCATOR_NEW -#define _GLIBCXX_TXN_SAFE transaction_safe -#define _GLIBCXX_TXN_SAFE_DYN transaction_safe_dynamic -#else -#define _GLIBCXX_TXN_SAFE -#define _GLIBCXX_TXN_SAFE_DYN -#endif - #else // !__cplusplus # define _GLIBCXX_BEGIN_EXTERN_C # define _GLIBCXX_END_EXTERN_C @@ -524,6 +510,28 @@ namespace std # define _GLIBCXX_WEAK_DEFINITION #endif +// By default, we assume that __GXX_WEAK__ also means that there is support +// for declaring functions as weak while not defining such functions. This +// allows for referring to functions provided by other libraries (e.g., +// libitm) without depending on them if the respective features are not used. +#ifndef _GLIBCXX_USE_WEAK_REF +# define _GLIBCXX_USE_WEAK_REF __GXX_WEAK__ +#endif + +// Conditionally enable annotations for the Transactional Memory TS on C++11. +// Most of the following conditions are due to limitations in the current +// implementation. +#if __cplusplus >= 201103L && _GLIBCXX_USE_CXX11_ABI \ + && _GLIBCXX_USE_DUAL_ABI && __cpp_transactional_memory >= 201505L \ + && !_GLIBCXX_FULLY_DYNAMIC_STRING && _GLIBCXX_USE_WEAK_REF \ + && _GLIBCXX_USE_ALLOCATOR_NEW +#define _GLIBCXX_TXN_SAFE transaction_safe +#define _GLIBCXX_TXN_SAFE_DYN transaction_safe_dynamic +#else +#define _GLIBCXX_TXN_SAFE +#define _GLIBCXX_TXN_SAFE_DYN +#endif + // The remainder of the prewritten config is automatic; all the // user hooks are listed above. diff --git a/libstdc++-v3/src/c++11/cow-stdexcept.cc b/libstdc++-v3/src/c++11/cow-stdexcept.cc index eddb36b..a0f505c 100644 --- a/libstdc++-v3/src/c++11/cow-stdexcept.cc +++ b/libstdc++-v3/src/c++11/cow-stdexcept.cc @@ -179,6 +179,13 @@ _GLIBCXX_END_NAMESPACE_VERSION // Furthermore, _Rep will always have been allocated or deallocated via // global new or delete, so nontransactional writes we do to _Rep cannot // interfere with transactional accesses. + +// We depend on having support for referencing functions declared weak that +// are not defined by us. Without such support, the exceptions will not be +// declared transaction-safe, so we just don't provide transactional clones +// in this case. +#if _GLIBCXX_USE_WEAK_REF + extern "C" { #ifndef _GLIBCXX_MANGLE_SIZE_T @@ -195,7 +202,6 @@ extern "C" { # define ITM_REGPARM #endif -#if __GXX_WEAK__ // Declare all libitm symbols we rely on, but make them weak so that we do // not depend on libitm. extern void* _ZGTtnaX (size_t sz) __attribute__((weak)); @@ -213,19 +219,6 @@ extern void _ITM_memcpyRnWt(void *, const void *, size_t) extern void _ITM_addUserCommitAction(void (*)(void *), uint64_t, void *) ITM_REGPARM __attribute__((weak)); -#else -// If there is no support for weak symbols, create dummies. The exceptions -// will not be declared transaction_safe in this case. -void* _ZGTtnaX (size_t) { return NULL; } -void _ZGTtdlPv (void*) { } -uint8_t _ITM_RU1(const uint8_t *) { return 0; } -uint32_t _ITM_RU4(const uint32_t *) { return 0; } -uint64_t _ITM_RU8(const uint64_t *) { return 0; } -void _ITM_memcpyRtWn(void *, const void *, size_t) { } -void _ITM_memcpyRnWt(void *, const void *, size_t) { } -void _ITM_addUserCommitAction(void (*)(void *), uint64_t, void *) { }; -#endif - } // A transactional version of basic_string::basic_string(const char *s) @@ -441,3 +434,5 @@ CTORDTOR(14overflow_error, std::overflow_error, runtime_error) CTORDTOR(15underflow_error, std::underflow_error, runtime_error) } + +#endif // _GLIBCXX_USE_WEAK_REF -- 2.7.4