[libcxx] r285100 - [libc++] Fix modules build - Rework __refstring definition
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Tue Oct 25 12:33:14 PDT 2016
Author: ericwf
Date: Tue Oct 25 14:33:14 2016
New Revision: 285100
URL: http://llvm.org/viewvc/llvm-project?rev=285100&view=rev
Log:
[libc++] Fix modules build - Rework __refstring definition
Summary:
`__libcpp_refstring` currently has two different definitions. First there is the complete definition in `<__refstring>` but there is also a second in `<stdexcept>`. The historical reason for this split is because both libc++ and libc++abi need to see the inline definitions of __libcpp_refstrings methods, but the `<stdexcept>` header doesn't. However this is an ODR violation and breaks the modules build.
This patch fixes the issue by creating a single class definition in `<stdexcept>` and changing `<__refstring>` to contain only the inline method definitions. This way both `libcxx/src/stdexcept.cpp` and `libcxxabi/src/stdexcept.cpp` see the same declaration in `<stdexcept>` and definitions in `<__refstring>`
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25603
Modified:
libcxx/trunk/include/__refstring
libcxx/trunk/include/stdexcept
libcxx/trunk/src/stdexcept.cpp
Modified: libcxx/trunk/include/__refstring
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__refstring?rev=285100&r1=285099&r2=285100&view=diff
==============================================================================
--- libcxx/trunk/include/__refstring (original)
+++ libcxx/trunk/include/__refstring Tue Oct 25 14:33:14 2016
@@ -11,6 +11,7 @@
#define _LIBCPP___REFSTRING
#include <__config>
+#include <stdexcept>
#include <cstddef>
#include <cstring>
#ifdef __APPLE__
@@ -20,119 +21,106 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-class _LIBCPP_HIDDEN __libcpp_refstring
-{
-private:
- const char* str_;
-
- typedef int count_t;
-
- struct _Rep_base
- {
- std::size_t len;
- std::size_t cap;
- count_t count;
- };
-
- static
- _Rep_base*
- rep_from_data(const char *data_) _NOEXCEPT
- {
- char *data = const_cast<char *>(data_);
- return reinterpret_cast<_Rep_base *>(data - sizeof(_Rep_base));
- }
- static
- char *
- data_from_rep(_Rep_base *rep) _NOEXCEPT
- {
- char *data = reinterpret_cast<char *>(rep);
- return data + sizeof(*rep);
- }
+namespace __refstring_imp { namespace {
+typedef int count_t;
-#ifdef __APPLE__
- static
- const char*
- compute_gcc_empty_string_storage() _NOEXCEPT
- {
- void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD);
- if (handle == nullptr)
- return nullptr;
- void* sym = dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE");
- if (sym == nullptr)
- return nullptr;
- return data_from_rep(reinterpret_cast<_Rep_base *>(sym));
- }
-
- static
- const char*
- get_gcc_empty_string_storage() _NOEXCEPT
- {
- static const char* p = compute_gcc_empty_string_storage();
- return p;
- }
+struct _Rep_base {
+ std::size_t len;
+ std::size_t cap;
+ count_t count;
+};
- bool
- uses_refcount() const
- {
- return str_ != get_gcc_empty_string_storage();
- }
-#else
- bool
- uses_refcount() const
- {
- return true;
- }
+inline _Rep_base* rep_from_data(const char *data_) noexcept {
+ char *data = const_cast<char *>(data_);
+ return reinterpret_cast<_Rep_base *>(data - sizeof(_Rep_base));
+}
+
+inline char * data_from_rep(_Rep_base *rep) noexcept {
+ char *data = reinterpret_cast<char *>(rep);
+ return data + sizeof(*rep);
+}
+
+#if defined(__APPLE__)
+inline
+const char* compute_gcc_empty_string_storage() _NOEXCEPT
+{
+ void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD);
+ if (handle == nullptr)
+ return nullptr;
+ void* sym = dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE");
+ if (sym == nullptr)
+ return nullptr;
+ return data_from_rep(reinterpret_cast<_Rep_base *>(sym));
+}
+
+inline
+const char*
+get_gcc_empty_string_storage() _NOEXCEPT
+{
+ static const char* p = compute_gcc_empty_string_storage();
+ return p;
+}
#endif
-public:
- explicit __libcpp_refstring(const char* msg) {
- std::size_t len = strlen(msg);
- _Rep_base* rep = static_cast<_Rep_base *>(::operator new(sizeof(*rep) + len + 1));
- rep->len = len;
- rep->cap = len;
- rep->count = 0;
- char *data = data_from_rep(rep);
- std::memcpy(data, msg, len + 1);
- str_ = data;
- }
+}} // namespace __refstring_imp
- __libcpp_refstring(const __libcpp_refstring& s) _NOEXCEPT : str_(s.str_)
- {
- if (uses_refcount())
- __sync_add_and_fetch(&rep_from_data(str_)->count, 1);
- }
+using namespace __refstring_imp;
- __libcpp_refstring& operator=(const __libcpp_refstring& s) _NOEXCEPT
+inline
+__libcpp_refstring::__libcpp_refstring(const char* msg) {
+ std::size_t len = strlen(msg);
+ _Rep_base* rep = static_cast<_Rep_base *>(::operator new(sizeof(*rep) + len + 1));
+ rep->len = len;
+ rep->cap = len;
+ rep->count = 0;
+ char *data = data_from_rep(rep);
+ std::memcpy(data, msg, len + 1);
+ __imp_ = data;
+}
+
+inline
+__libcpp_refstring::__libcpp_refstring(const __libcpp_refstring &s) _NOEXCEPT
+ : __imp_(s.__imp_)
+{
+ if (__uses_refcount())
+ __sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
+}
+
+inline
+__libcpp_refstring& __libcpp_refstring::operator=(__libcpp_refstring const& s) _NOEXCEPT {
+ bool adjust_old_count = __uses_refcount();
+ struct _Rep_base *old_rep = rep_from_data(__imp_);
+ __imp_ = s.__imp_;
+ if (__uses_refcount())
+ __sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
+ if (adjust_old_count)
{
- bool adjust_old_count = uses_refcount();
- struct _Rep_base *old_rep = rep_from_data(str_);
- str_ = s.str_;
- if (uses_refcount())
- __sync_add_and_fetch(&rep_from_data(str_)->count, 1);
- if (adjust_old_count)
+ if (__sync_add_and_fetch(&old_rep->count, count_t(-1)) < 0)
{
- if (__sync_add_and_fetch(&old_rep->count, count_t(-1)) < 0)
- {
- ::operator delete(old_rep);
- }
+ ::operator delete(old_rep);
}
- return *this;
}
+ return *this;
+}
- ~__libcpp_refstring()
- {
- if (uses_refcount())
- {
- _Rep_base* rep = rep_from_data(str_);
- if (__sync_add_and_fetch(&rep->count, count_t(-1)) < 0)
- {
- ::operator delete(rep);
- }
+inline
+__libcpp_refstring::~__libcpp_refstring() {
+ if (__uses_refcount()) {
+ _Rep_base* rep = rep_from_data(__imp_);
+ if (__sync_add_and_fetch(&rep->count, count_t(-1)) < 0) {
+ ::operator delete(rep);
}
}
+}
- const char* c_str() const _NOEXCEPT {return str_;}
-};
+inline
+bool __libcpp_refstring::__uses_refcount() const {
+#ifdef __APPLE__
+ return __imp_ != get_gcc_empty_string_storage();
+#else
+ return true;
+#endif
+}
_LIBCPP_END_NAMESPACE_STD
Modified: libcxx/trunk/include/stdexcept
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/stdexcept?rev=285100&r1=285099&r2=285100&view=diff
==============================================================================
--- libcxx/trunk/include/stdexcept (original)
+++ libcxx/trunk/include/stdexcept Tue Oct 25 14:33:14 2016
@@ -53,17 +53,23 @@ public:
#pragma GCC system_header
#endif
-#ifndef _LIBCPP___REFSTRING
_LIBCPP_BEGIN_NAMESPACE_STD
-class _LIBCPP_HIDDEN __libcpp_refstring {
-#ifdef __clang__
- const char *__imp_ __attribute__((__unused__)); // only clang emits a warning
-#else
- const char *__imp_;
-#endif
+
+class _LIBCPP_HIDDEN __libcpp_refstring
+{
+ const char* __imp_;
+
+ bool __uses_refcount() const;
+public:
+ explicit __libcpp_refstring(const char* msg);
+ __libcpp_refstring(const __libcpp_refstring& s) _NOEXCEPT;
+ __libcpp_refstring& operator=(const __libcpp_refstring& s) _NOEXCEPT;
+ ~__libcpp_refstring();
+
+ const char* c_str() const _NOEXCEPT {return __imp_;}
};
+
_LIBCPP_END_NAMESPACE_STD
-#endif
namespace std // purposefully not using versioning namespace
{
Modified: libcxx/trunk/src/stdexcept.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/stdexcept.cpp?rev=285100&r1=285099&r2=285100&view=diff
==============================================================================
--- libcxx/trunk/src/stdexcept.cpp (original)
+++ libcxx/trunk/src/stdexcept.cpp Tue Oct 25 14:33:14 2016
@@ -7,11 +7,11 @@
//
//===----------------------------------------------------------------------===//
-#include "__refstring"
#include "stdexcept"
#include "new"
#include "string"
#include "system_error"
+#include "__refstring"
/* For _LIBCPPABI_VERSION */
#if defined(LIBCXX_BUILDING_LIBCXXABI) || defined(__APPLE__) || defined(LIBCXXRT)
@@ -20,6 +20,7 @@
static_assert(sizeof(std::__libcpp_refstring) == sizeof(const char *), "");
+
namespace std // purposefully not using versioning namespace
{
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