D: Implement GCC emutls in druntime
* libdruntime/Makefile.am: Add emutls and gthread files.
* libdruntime/Makefile.in: Regenerate.
* libdruntime/gcc/emutls.d: New file. Implement GC-compatible emutls.
* libdruntime/gcc/gthread.d: New file.
* libdruntime/gcc/sections/elf_shared.d: Integrate emutls support.
* testsuite/libphobos.allocations/tls_gc_integration.d: New test for
TLS.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@270568 138bc75d-0d04-0410-961f-82ee72b054a4
diff --git a/libphobos/ChangeLog b/libphobos/ChangeLog
index 9d442f4..131d7f9 100644
--- a/libphobos/ChangeLog
+++ b/libphobos/ChangeLog
@@ -1,3 +1,12 @@
+2019-04-25 Johannes Pfau <johannespfau@gmail.com>
+
+ * libdruntime/Makefile.am: Add emutls and gthread files.
+ * libdruntime/Makefile.in: Regenerate.
+ * libdruntime/gcc/emutls.d: New file. Implement GC-compatible emutls.
+ * libdruntime/gcc/gthread.d: New file.
+ * libdruntime/gcc/sections/elf_shared.d: Integrate emutls support.
+ * testsuite/libphobos.allocations/tls_gc_integration.d: New test for TLS.
+
2019-04-25 Iain Buclaw <ibuclaw@gdcproject.org>
* testsuite/Makefile.am: Set PWD_COMMAND.
diff --git a/libphobos/libdruntime/Makefile.am b/libphobos/libdruntime/Makefile.am
index b981f23..bf9bff09 100644
--- a/libphobos/libdruntime/Makefile.am
+++ b/libphobos/libdruntime/Makefile.am
@@ -161,7 +161,8 @@
core/sync/config.d core/sync/exception.d core/sync/mutex.d \
core/sync/rwmutex.d core/sync/semaphore.d core/thread.d core/time.d \
core/vararg.d gcc/attribute.d gcc/backtrace.d gcc/builtins.d gcc/deh.d \
- gcc/sections/android.d gcc/sections/elf_shared.d gcc/sections/osx.d \
+ gcc/emutls.d gcc/gthread.d gcc/sections/android.d \
+ gcc/sections/elf_shared.d gcc/sections/osx.d \
gcc/sections/package.d gcc/sections/win32.d gcc/sections/win64.d \
gcc/unwind/arm.d gcc/unwind/arm_common.d gcc/unwind/c6x.d \
gcc/unwind/generic.d gcc/unwind/package.d gcc/unwind/pe.d object.d \
diff --git a/libphobos/libdruntime/Makefile.in b/libphobos/libdruntime/Makefile.in
index eb290b6..19ee94f 100644
--- a/libphobos/libdruntime/Makefile.in
+++ b/libphobos/libdruntime/Makefile.in
@@ -203,10 +203,10 @@
core/sync/exception.lo core/sync/mutex.lo core/sync/rwmutex.lo \
core/sync/semaphore.lo core/thread.lo core/time.lo \
core/vararg.lo gcc/attribute.lo gcc/backtrace.lo \
- gcc/builtins.lo gcc/deh.lo gcc/sections/android.lo \
- gcc/sections/elf_shared.lo gcc/sections/osx.lo \
- gcc/sections/package.lo gcc/sections/win32.lo \
- gcc/sections/win64.lo gcc/unwind/arm.lo \
+ gcc/builtins.lo gcc/deh.lo gcc/emutls.lo gcc/gthread.lo \
+ gcc/sections/android.lo gcc/sections/elf_shared.lo \
+ gcc/sections/osx.lo gcc/sections/package.lo \
+ gcc/sections/win32.lo gcc/sections/win64.lo gcc/unwind/arm.lo \
gcc/unwind/arm_common.lo gcc/unwind/c6x.lo \
gcc/unwind/generic.lo gcc/unwind/package.lo gcc/unwind/pe.lo \
object.lo rt/aApply.lo rt/aApplyR.lo rt/aaA.lo rt/adi.lo \
@@ -757,7 +757,8 @@
core/sync/config.d core/sync/exception.d core/sync/mutex.d \
core/sync/rwmutex.d core/sync/semaphore.d core/thread.d core/time.d \
core/vararg.d gcc/attribute.d gcc/backtrace.d gcc/builtins.d gcc/deh.d \
- gcc/sections/android.d gcc/sections/elf_shared.d gcc/sections/osx.d \
+ gcc/emutls.d gcc/gthread.d gcc/sections/android.d \
+ gcc/sections/elf_shared.d gcc/sections/osx.d \
gcc/sections/package.d gcc/sections/win32.d gcc/sections/win64.d \
gcc/unwind/arm.d gcc/unwind/arm_common.d gcc/unwind/c6x.d \
gcc/unwind/generic.d gcc/unwind/package.d gcc/unwind/pe.d object.d \
@@ -1104,6 +1105,8 @@
gcc/backtrace.lo: gcc/$(am__dirstamp)
gcc/builtins.lo: gcc/$(am__dirstamp)
gcc/deh.lo: gcc/$(am__dirstamp)
+gcc/emutls.lo: gcc/$(am__dirstamp)
+gcc/gthread.lo: gcc/$(am__dirstamp)
gcc/sections/$(am__dirstamp):
@$(MKDIR_P) gcc/sections
@: > gcc/sections/$(am__dirstamp)
diff --git a/libphobos/libdruntime/gcc/emutls.d b/libphobos/libdruntime/gcc/emutls.d
new file mode 100644
index 0000000..461f20d
--- /dev/null
+++ b/libphobos/libdruntime/gcc/emutls.d
@@ -0,0 +1,316 @@
+// GNU D Compiler emulated TLS routines.
+// Copyright (C) 2019 Free Software Foundation, Inc.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+// for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+// This code is based on the libgcc emutls.c emulated TLS support.
+
+module gcc.emutls;
+
+import core.atomic, core.stdc.stdlib, core.stdc.string, core.sync.mutex;
+import rt.util.container.array, rt.util.container.hashtab;
+import core.internal.traits : classInstanceAlignment;
+import gcc.builtins, gcc.gthread;
+
+version (GNU_EMUTLS): private:
+
+alias word = __builtin_machine_uint;
+alias pointer = __builtin_pointer_uint;
+alias TlsArray = Array!(void**);
+
+/*
+ * TLS control data emitted by GCC for every TLS variable.
+ */
+struct __emutls_object
+{
+ word size;
+ word align_;
+ union
+ {
+ pointer offset;
+ void* ptr;
+ }
+
+ ubyte* templ;
+}
+
+// Per-thread key to obtain the per-thread TLS variable array
+__gshared __gthread_key_t emutlsKey;
+// Largest, currently assigned TLS variable offset
+__gshared pointer emutlsMaxOffset = 0;
+// Contains the size of the TLS variables (for GC)
+__gshared Array!word emutlsSizes;
+// Contains the TLS variable array for single-threaded apps
+__gshared TlsArray singleArray;
+// List of all currently alive TlsArrays (for GC)
+__gshared HashTab!(TlsArray*, TlsArray*) emutlsArrays;
+
+// emutlsMutex Mutex + @nogc handling
+enum mutexAlign = classInstanceAlignment!Mutex;
+enum mutexClassInstanceSize = __traits(classInstanceSize, Mutex);
+__gshared align(mutexAlign) void[mutexClassInstanceSize] _emutlsMutex;
+
+@property Mutex emutlsMutex() nothrow @nogc
+{
+ return cast(Mutex) _emutlsMutex.ptr;
+}
+
+/*
+ * Global (de)initialization functions
+ */
+extern (C) void _d_emutls_init() nothrow @nogc
+{
+ memcpy(_emutlsMutex.ptr, typeid(Mutex).initializer.ptr, _emutlsMutex.length);
+ (cast(Mutex) _emutlsMutex.ptr).__ctor();
+
+ if (__gthread_key_create(&emutlsKey, &emutlsDestroyThread) != 0)
+ abort();
+}
+
+__gshared __gthread_once_t initOnce = GTHREAD_ONCE_INIT;
+
+/*
+ * emutls main entrypoint, called by GCC for each TLS variable access.
+ */
+extern (C) void* __emutls_get_address(shared __emutls_object* obj) nothrow @nogc
+{
+ pointer offset;
+ if (__gthread_active_p())
+ {
+ // Obtain the offset index into the TLS array (same for all-threads)
+ // for requested var. If it is unset, obtain a new offset index.
+ offset = atomicLoad!(MemoryOrder.acq, pointer)(obj.offset);
+ if (__builtin_expect(offset == 0, 0))
+ {
+ __gthread_once(&initOnce, &_d_emutls_init);
+ emutlsMutex.lock_nothrow();
+
+ offset = obj.offset;
+ if (offset == 0)
+ {
+ offset = ++emutlsMaxOffset;
+
+ emutlsSizes.ensureLength(offset);
+ // Note: it's important that we copy any data from obj and
+ // do not keep an reference to obj itself: If a library is
+ // unloaded, its tls variables are not removed from the arrays
+ // and the GC will still scan these. If we then try to reference
+ // a pointer to the data segment of an unloaded library, this
+ // will crash.
+ emutlsSizes[offset - 1] = obj.size;
+
+ atomicStore!(MemoryOrder.rel, pointer)(obj.offset, offset);
+ }
+ emutlsMutex.unlock_nothrow();
+ }
+ }
+ // For single-threaded systems, don't synchronize
+ else
+ {
+ if (__builtin_expect(obj.offset == 0, 0))
+ {
+ offset = ++emutlsMaxOffset;
+
+ emutlsSizes.ensureLength(offset);
+ emutlsSizes[offset - 1] = obj.size;
+
+ obj.offset = offset;
+ }
+ }
+
+ TlsArray* arr;
+ if (__gthread_active_p())
+ arr = cast(TlsArray*) __gthread_getspecific(emutlsKey);
+ else
+ arr = &singleArray;
+
+ // This will always be false for singleArray
+ if (__builtin_expect(arr == null, 0))
+ {
+ arr = mallocTlsArray(offset);
+ __gthread_setspecific(emutlsKey, arr);
+ emutlsMutex.lock_nothrow();
+ emutlsArrays[arr] = arr;
+ emutlsMutex.unlock_nothrow();
+ }
+ // Check if we have to grow the per-thread array
+ else if (__builtin_expect(offset > arr.length, 0))
+ {
+ (*arr).ensureLength(offset);
+ }
+
+ // Offset 0 is used as a not-initialized marker above. In the
+ // TLS array, we start at 0.
+ auto index = offset - 1;
+
+ // Get the per-thread pointer from the TLS array
+ void** ret = (*arr)[index];
+ if (__builtin_expect(ret == null, 0))
+ {
+ // Initial access, have to allocate the storage
+ ret = emutlsAlloc(obj);
+ (*arr)[index] = ret;
+ }
+
+ return ret;
+}
+
+// 1:1 copy from libgcc emutls.c
+extern (C) void __emutls_register_common(__emutls_object* obj, word size, word align_, ubyte* templ) nothrow @nogc
+{
+ if (obj.size < size)
+ {
+ obj.size = size;
+ obj.templ = null;
+ }
+ if (obj.align_ < align_)
+ obj.align_ = align_;
+ if (templ && size == obj.size)
+ obj.templ = templ;
+}
+
+// 1:1 copy from libgcc emutls.c
+void** emutlsAlloc(shared __emutls_object* obj) nothrow @nogc
+{
+ void* ptr;
+ void* ret;
+ enum pointerSize = (void*).sizeof;
+
+ /* We could use here posix_memalign if available and adjust
+ emutls_destroy accordingly. */
+ if ((cast() obj).align_ <= pointerSize)
+ {
+ ptr = malloc((cast() obj).size + pointerSize);
+ if (ptr == null)
+ abort();
+ (cast(void**) ptr)[0] = ptr;
+ ret = ptr + pointerSize;
+ }
+ else
+ {
+ ptr = malloc(obj.size + pointerSize + obj.align_ - 1);
+ if (ptr == null)
+ abort();
+ ret = cast(void*)((cast(pointer)(ptr + pointerSize + obj.align_ - 1)) & ~cast(
+ pointer)(obj.align_ - 1));
+ (cast(void**) ret)[-1] = ptr;
+ }
+
+ if (obj.templ)
+ memcpy(ret, cast(ubyte*) obj.templ, cast() obj.size);
+ else
+ memset(ret, 0, cast() obj.size);
+
+ return cast(void**) ret;
+}
+
+/*
+ * When a thread has finished, remove the TLS array from the GC
+ * scan list emutlsArrays, free all allocated TLS variables and
+ * finally free the array.
+ */
+extern (C) void emutlsDestroyThread(void* ptr) nothrow @nogc
+{
+ auto arr = cast(TlsArray*) ptr;
+ emutlsMutex.lock_nothrow();
+ emutlsArrays.remove(arr);
+ emutlsMutex.unlock_nothrow();
+
+ foreach (entry; *arr)
+ {
+ if (entry)
+ free(entry[-1]);
+ }
+
+ free(arr);
+}
+
+/*
+ * Allocate a new TLS array, set length according to offset.
+ */
+TlsArray* mallocTlsArray(pointer offset = 0) nothrow @nogc
+{
+ static assert(TlsArray.alignof == (void*).alignof);
+ void[] data = malloc(TlsArray.sizeof)[0 .. TlsArray.sizeof];
+ if (data.ptr == null)
+ abort();
+
+ static immutable TlsArray init = TlsArray.init;
+ memcpy(data.ptr, &init, data.length);
+ (cast(TlsArray*) data).length = 32;
+ return cast(TlsArray*) data.ptr;
+}
+
+/*
+ * Make sure array is large enough to hold an entry for offset.
+ * Note: the array index will be offset - 1!
+ */
+void ensureLength(Value)(ref Array!(Value) arr, size_t offset) nothrow @nogc
+{
+ // index is offset-1
+ if (offset > arr.length)
+ {
+ auto newSize = arr.length * 2;
+ if (offset > newSize)
+ newSize = offset + 32;
+ arr.length = newSize;
+ }
+}
+
+// Public interface
+public:
+void _d_emutls_scan(scope void delegate(void* pbeg, void* pend) nothrow cb) nothrow
+{
+ void scanArray(scope TlsArray* arr) nothrow
+ {
+ foreach (index, entry; *arr)
+ {
+ auto ptr = cast(void*) entry;
+ if (ptr)
+ cb(ptr, ptr + emutlsSizes[index]);
+ }
+ }
+
+ __gthread_once(&initOnce, &_d_emutls_init);
+ emutlsMutex.lock_nothrow();
+ // this code is effectively nothrow
+ try
+ {
+ foreach (arr, value; emutlsArrays)
+ {
+ scanArray(arr);
+ }
+ }
+ catch (Exception)
+ {
+ }
+ emutlsMutex.unlock_nothrow();
+ scanArray(&singleArray);
+}
+
+// Call this after druntime has been unloaded
+void _d_emutls_destroy() nothrow @nogc
+{
+ if (__gthread_key_delete(emutlsKey) != 0)
+ abort();
+
+ (cast(Mutex) _emutlsMutex.ptr).__dtor();
+ destroy(emutlsArrays);
+}
diff --git a/libphobos/libdruntime/gcc/gthread.d b/libphobos/libdruntime/gcc/gthread.d
new file mode 100644
index 0000000..580fdcb
--- /dev/null
+++ b/libphobos/libdruntime/gcc/gthread.d
@@ -0,0 +1,127 @@
+// GNU D Compiler thread support for emulated TLS routines.
+// Copyright (C) 2019 Free Software Foundation, Inc.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+// for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+module gcc.gthread;
+import gcc.config;
+
+extern (C) nothrow @nogc:
+
+alias GthreadDestroyFn = extern (C) void function(void*);
+alias GthreadOnceFn = extern (C) void function();
+
+static if (GNU_Thread_Model == ThreadModel.Posix)
+{
+ import core.sys.posix.pthread;
+
+ alias __gthread_key_create = pthread_key_create;
+ alias __gthread_key_delete = pthread_key_delete;
+ alias __gthread_getspecific = pthread_getspecific;
+ alias __gthread_setspecific = pthread_setspecific;
+ alias __gthread_once = pthread_once;
+ alias __gthread_key_t = pthread_key_t;
+ alias __gthread_once_t = pthread_once_t;
+ enum GTHREAD_ONCE_INIT = PTHREAD_ONCE_INIT;
+
+ // TODO: FreeBSD and Solaris exposes a dummy POSIX threads
+ // interface that will need to be handled here.
+ extern (D) int __gthread_active_p()
+ {
+ return 1;
+ }
+}
+else static if (GNU_Thread_Model == ThreadModel.Single)
+{
+ alias __gthread_key_t = int;
+ alias __gthread_once_t = int;
+ enum GTHREAD_ONCE_INIT = 0;
+
+ extern (D) int __gthread_key_create(__gthread_key_t*, GthreadDestroyFn)
+ {
+ return 0;
+ }
+
+ extern (D) int __gthread_key_delete(__gthread_key_t)
+ {
+ return 0;
+ }
+
+ extern (D) void* __gthread_getspecific(__gthread_key_t)
+ {
+ return null;
+ }
+
+ extern (D) int __gthread_setspecific(__gthread_key_t, void*)
+ {
+ return 0;
+ }
+
+ extern (D) int __gthread_once(__gthread_once_t*, GthreadOnceFn)
+ {
+ return 0;
+ }
+
+ extern (D) int __gthread_active_p()
+ {
+ return 0;
+ }
+}
+else static if (GNU_Thread_Model == ThreadModel.Win32)
+{
+ struct __gthread_once_t
+ {
+ INT done;
+ LONG started;
+ }
+
+ int __gthr_win32_key_create(__gthread_key_t* keyp, GthreadDestroyFn dtor);
+ int __gthr_win32_key_delete(__gthread_key_t key);
+ void* __gthr_win32_getspecific(__gthread_key_t key);
+ int __gthr_win32_setspecific(__gthread_key_t key, const void* ptr);
+ int __gthr_win32_once(__gthread_once_t* once, GthreadOnceFn);
+
+ alias __gthread_key_create = __gthr_win32_key_create;
+ alias __gthread_key_delete = __gthr_win32_key_delete;
+ alias __gthread_getspecific = __gthr_win32_getspecific;
+ alias __gthread_setspecific = __gthr_win32_setspecific;
+ alias __gthread_once = __gthr_win32_once;
+ enum GTHREAD_ONCE_INIT = __gthread_once_t(0, -1);
+ alias __gthread_key_t = c_ulong;
+
+ version (MinGW)
+ {
+ // Mingw runtime >= v0.3 provides a magic variable that is set to nonzero
+ // if -mthreads option was specified, or 0 otherwise.
+ extern __gshared int _CRT_MT;
+ }
+
+ extern (D) int __gthread_active_p()
+ {
+ version (MinGW)
+ return _CRT_MT;
+ else
+ return 1;
+ }
+}
+else
+{
+ static assert(false, "Not implemented");
+}
diff --git a/libphobos/libdruntime/gcc/sections/elf_shared.d b/libphobos/libdruntime/gcc/sections/elf_shared.d
index d92e4cd..3a2c85c 100644
--- a/libphobos/libdruntime/gcc/sections/elf_shared.d
+++ b/libphobos/libdruntime/gcc/sections/elf_shared.d
@@ -222,8 +222,16 @@
void scanTLSRanges(Array!(ThreadDSO)* tdsos, scope ScanDG dg) nothrow
{
- foreach (ref tdso; *tdsos)
- dg(tdso._tlsRange.ptr, tdso._tlsRange.ptr + tdso._tlsRange.length);
+ version (GNU_EMUTLS)
+ {
+ import gcc.emutls;
+ _d_emutls_scan(dg);
+ }
+ else
+ {
+ foreach (ref tdso; *tdsos)
+ dg(tdso._tlsRange.ptr, tdso._tlsRange.ptr + tdso._tlsRange.length);
+ }
}
// interface for core.thread to inherit loaded libraries
@@ -310,8 +318,16 @@
void scanTLSRanges(Array!(void[])* rngs, scope ScanDG dg) nothrow
{
- foreach (rng; *rngs)
- dg(rng.ptr, rng.ptr + rng.length);
+ version (GNU_EMUTLS)
+ {
+ import gcc.emutls;
+ _d_emutls_scan(dg);
+ }
+ else
+ {
+ foreach (rng; *rngs)
+ dg(rng.ptr, rng.ptr + rng.length);
+ }
}
}
@@ -519,6 +535,11 @@
_handleToDSO.reset();
}
finiLocks();
+ version (GNU_EMUTLS)
+ {
+ import gcc.emutls;
+ _d_emutls_destroy();
+ }
}
}
}
@@ -805,40 +826,46 @@
break;
case PT_TLS: // TLS segment
- safeAssert(!pdso._tlsSize, "Multiple TLS segments in image header.");
- static if (OS_Have_Dlpi_Tls_Modid)
+ version (GNU_EMUTLS)
{
- pdso._tlsMod = info.dlpi_tls_modid;
- pdso._tlsSize = phdr.p_memsz;
- }
- else version (Solaris)
- {
- struct Rt_map
- {
- Link_map rt_public;
- const char* rt_pathname;
- c_ulong rt_padstart;
- c_ulong rt_padimlen;
- c_ulong rt_msize;
- uint rt_flags;
- uint rt_flags1;
- c_ulong rt_tlsmodid;
- }
-
- Rt_map* map;
- version (Shared)
- dlinfo(handleForName(info.dlpi_name), RTLD_DI_LINKMAP, &map);
- else
- dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &map);
- // Until Solaris 11.4, tlsmodid for the executable is 0.
- // Let it start at 1 as the rest of the code expects.
- pdso._tlsMod = map.rt_tlsmodid + 1;
- pdso._tlsSize = phdr.p_memsz;
}
else
{
- pdso._tlsMod = 0;
- pdso._tlsSize = 0;
+ safeAssert(!pdso._tlsSize, "Multiple TLS segments in image header.");
+ static if (OS_Have_Dlpi_Tls_Modid)
+ {
+ pdso._tlsMod = info.dlpi_tls_modid;
+ pdso._tlsSize = phdr.p_memsz;
+ }
+ else version (Solaris)
+ {
+ struct Rt_map
+ {
+ Link_map rt_public;
+ const char* rt_pathname;
+ c_ulong rt_padstart;
+ c_ulong rt_padimlen;
+ c_ulong rt_msize;
+ uint rt_flags;
+ uint rt_flags1;
+ c_ulong rt_tlsmodid;
+ }
+
+ Rt_map* map;
+ version (Shared)
+ dlinfo(handleForName(info.dlpi_name), RTLD_DI_LINKMAP, &map);
+ else
+ dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &map);
+ // Until Solaris 11.4, tlsmodid for the executable is 0.
+ // Let it start at 1 as the rest of the code expects.
+ pdso._tlsMod = map.rt_tlsmodid + 1;
+ pdso._tlsSize = phdr.p_memsz;
+ }
+ else
+ {
+ pdso._tlsMod = 0;
+ pdso._tlsSize = 0;
+ }
}
break;
diff --git a/libphobos/testsuite/libphobos.allocations/tls_gc_integration.d b/libphobos/testsuite/libphobos.allocations/tls_gc_integration.d
new file mode 100644
index 0000000..44eb40c
--- /dev/null
+++ b/libphobos/testsuite/libphobos.allocations/tls_gc_integration.d
@@ -0,0 +1,50 @@
+import core.memory, core.thread, core.bitop;
+
+/*
+ * This test repeatedly performs operations on GC-allocated objects which
+ * are only reachable from TLS storage. Tests are performed in multiple threads
+ * and GC collections are triggered repeatedly, so if the GC does not properly
+ * scan TLS memory, this provokes a crash.
+ */
+class TestTLS
+{
+ uint a;
+ void addNumber()
+ {
+ auto val = volatileLoad(&a);
+ val++;
+ volatileStore(&a, val);
+ }
+}
+
+TestTLS tlsPtr;
+
+static this()
+{
+ tlsPtr = new TestTLS();
+}
+
+void main()
+{
+ void runThread()
+ {
+ for (size_t i = 0; i < 100; i++)
+ {
+ Thread.sleep(10.msecs);
+ tlsPtr.addNumber();
+ GC.collect();
+ }
+ }
+
+ Thread[] threads;
+ for (size_t i = 0; i < 20; i++)
+ {
+ auto t = new Thread(&runThread);
+ threads ~= t;
+ t.start();
+ }
+ runThread();
+
+ foreach (thread; threads)
+ thread.join();
+}
