0002-Revert-Make-libc-abi-use-the-implementation-of-__num.patch

From c3520f9c833c6ae5d00530a54028ff4a5befc463 Mon Sep 17 00:00:00 2001
From: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Date: Mon, 29 Dec 2014 22:05:22 -0800
Subject: [PATCH 2/2] Revert "Make libc++abi use the implementation of __numstr
 from libc++. No functionality change, just removal of duplicated code."

This reverts commit f7a83f7f3b5788e3ead1c7f2063994699df55085.
---
 src/stdexcept.cpp | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 127 insertions(+), 6 deletions(-)

diff --git a/src/stdexcept.cpp b/src/stdexcept.cpp
index bd6789e..246eea4 100644
--- a/src/stdexcept.cpp
+++ b/src/stdexcept.cpp
@@ -7,7 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "__refstring"
 #include "stdexcept"
 #include "new"
 #include <cstdlib>
@@ -15,25 +14,147 @@
 #include <cstdint>
 #include <cstddef>
 
-static_assert(sizeof(std::__libcpp_refstring) == sizeof(const char *), "");
+#if __APPLE__
+#include <dlfcn.h>
+#include <mach-o/dyld.h>
+#endif
+
+// Note:  optimize for size
+
+#pragma GCC visibility push(hidden)
+
+namespace
+{
+
+class __libcpp_nmstr
+{
+private:
+    const char* str_;
+
+    typedef int count_t;
+
+    struct _Rep_base
+    {
+        std::size_t len;
+        std::size_t cap;
+        count_t     count;
+    };
+
+    static const std::ptrdiff_t offset = static_cast<std::ptrdiff_t>(sizeof(_Rep_base));
+
+    count_t& count() const _NOEXCEPT {return ((_Rep_base*)(str_ - offset))->count;}
+
+#if __APPLE__
+    static
+    const void*
+    compute_gcc_empty_string_storage() _NOEXCEPT
+    {
+        void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD);
+        if (handle == 0)
+            return 0;
+        return (const char*)dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE") + offset;
+    }
+    
+    static
+    const void*
+    get_gcc_empty_string_storage() _NOEXCEPT
+    {
+        static const void* p = compute_gcc_empty_string_storage();
+        return p;
+    }
+#endif
+
+public:
+    explicit __libcpp_nmstr(const char* msg);
+    __libcpp_nmstr(const __libcpp_nmstr& s) _NOEXCEPT;
+    __libcpp_nmstr& operator=(const __libcpp_nmstr& s) _NOEXCEPT;
+    ~__libcpp_nmstr();
+    const char* c_str() const _NOEXCEPT {return str_;}
+};
+
+__libcpp_nmstr::__libcpp_nmstr(const char* msg)
+{
+    std::size_t len = strlen(msg);
+    str_ = static_cast<const char*>(::operator new(len + 1 + offset));
+    _Rep_base* c = (_Rep_base*)str_;
+    c->len = c->cap = len;
+    str_ += offset;
+    count() = 0;
+    std::memcpy(const_cast<char*>(c_str()), msg, len + 1);
+}
+
+inline
+__libcpp_nmstr::__libcpp_nmstr(const __libcpp_nmstr& s) _NOEXCEPT
+    : str_(s.str_)
+{
+#if __APPLE__
+    if (str_ != get_gcc_empty_string_storage())
+#endif
+        __sync_add_and_fetch(&count(), 1);
+}
+
+__libcpp_nmstr&
+__libcpp_nmstr::operator=(const __libcpp_nmstr& s) _NOEXCEPT
+{
+    const char* p = str_;
+    str_ = s.str_;
+#if __APPLE__
+    if (str_ != get_gcc_empty_string_storage())
+#endif
+        __sync_add_and_fetch(&count(), 1);
+#if __APPLE__
+    if (p != get_gcc_empty_string_storage())
+#endif
+        if (__sync_add_and_fetch((count_t*)(p-sizeof(count_t)), count_t(-1)) < 0)
+        {
+            ::operator delete(const_cast<char*>(p-offset));
+        }
+    return *this;
+}
+
+inline
+__libcpp_nmstr::~__libcpp_nmstr()
+{
+#if __APPLE__
+    if (str_ != get_gcc_empty_string_storage())
+#endif
+        if (__sync_add_and_fetch(&count(), count_t(-1)) < 0)
+        {
+            ::operator delete(const_cast<char*>(str_ - offset));
+        }
+}
+
+}
+
+#pragma GCC visibility pop
 
 namespace std  // purposefully not using versioning namespace
 {
 
-logic_error::~logic_error() _NOEXCEPT {}
+logic_error::~logic_error() _NOEXCEPT
+{
+    __libcpp_nmstr& s = (__libcpp_nmstr&)__imp_;
+    s.~__libcpp_nmstr();
+}
 
 const char*
 logic_error::what() const _NOEXCEPT
 {
-    return __imp_.c_str();
+    __libcpp_nmstr& s = (__libcpp_nmstr&)__imp_;
+    return s.c_str();
 }
 
-runtime_error::~runtime_error() _NOEXCEPT {}
+runtime_error::~runtime_error() _NOEXCEPT
+{
+    __libcpp_nmstr& s = (__libcpp_nmstr&)__imp_;
+    s.~__libcpp_nmstr();
+}
 
 const char*
 runtime_error::what() const _NOEXCEPT
 {
-    return __imp_.c_str();
+    __libcpp_nmstr& s = (__libcpp_nmstr&)__imp_;
+    return s.c_str();
 }
 
 domain_error::~domain_error() _NOEXCEPT {}
-- 
2.6.2