[PATCH 0/2] MR10160: winecrt0: Add support for thread-local variables.

[Jacek Caban (＠jacek)]

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10160

[PATCH 1/2] winecrt0: Add _tls_used support.

[Jacek Caban]

From: Jacek Caban <[e-mail]>

---
 dlls/winecrt0/Makefile.in |  1 +
 dlls/winecrt0/tls.c       | 55 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 dlls/winecrt0/tls.c

diff --git a/dlls/winecrt0/Makefile.in b/dlls/winecrt0/Makefile.in
index 5b0d5705174..5893c98bf62 100644
--- a/dlls/winecrt0/Makefile.in
+++ b/dlls/winecrt0/Makefile.in
@@ -22,4 +22,5 @@ SOURCES = \
 	register.c \
 	setjmp.c \
 	stub.c \
+	tls.c \
 	unix_lib.c
diff --git a/dlls/winecrt0/tls.c b/dlls/winecrt0/tls.c
new file mode 100644
index 00000000000..67f52e0e5da
--- /dev/null
+++ b/dlls/winecrt0/tls.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2026 Jacek Caban for CodeWeavers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifdef __WINE_PE_BUILD
+
+#include <stdarg.h>
+#include "windef.h"
+#include "winbase.h"
+#include "wine/asm.h"
+
+#ifdef __i386__
+/* Offset of ThreadLocalStoragePointer in the TEB, the compiler uses %fs:_tls_array to access it. */
+asm( ".globl " __ASM_NAME("_tls_array") "\n\t"
+     __ASM_NAME("_tls_array") "=44" );
+#endif
+
+int _tls_index = 0;
+
+__attribute__((section(".tls")))     char _tls_start = 0;
+__attribute__((section(".tls$ZZZ"))) char _tls_end = 0;
+
+__attribute__((section(".CRT$XLA"))) void *__xl_a = 0;
+__attribute__((section(".CRT$XLZ"))) void *__xl_z = 0;
+
+const struct
+{
+    void *StartAddressOfRawData;
+    void *EndAddressOfRawData;
+    void *AddressOfIndex;
+    void *AddressOfCallBacks;
+    ULONG SizeOfZeroFill;
+    ULONG Characteristics;
+} _tls_used = {
+    &_tls_start,
+    &_tls_end,
+    &_tls_index,
+    &__xl_a + 1,
+};
+
+#endif
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10160

[PATCH 2/2] compiler-rt: Import emutls.c.

[Jacek Caban]

From: Jacek Caban <[e-mail]>

---
 libs/compiler-rt/Makefile.in           |   1 +
 libs/compiler-rt/lib/builtins/emutls.c | 392 +++++++++++++++++++++++++
 2 files changed, 393 insertions(+)
 create mode 100644 libs/compiler-rt/lib/builtins/emutls.c

diff --git a/libs/compiler-rt/Makefile.in b/libs/compiler-rt/Makefile.in
index fba197ccea1..9cc853b3872 100644
--- a/libs/compiler-rt/Makefile.in
+++ b/libs/compiler-rt/Makefile.in
@@ -12,6 +12,7 @@ SOURCES = \
 	lib/builtins/divmodsi4.c \
 	lib/builtins/divsi3.c \
 	lib/builtins/divti3.c \
+	lib/builtins/emutls.c \
 	lib/builtins/fixdfdi.c \
 	lib/builtins/fixsfdi.c \
 	lib/builtins/fixunsdfdi.c \
diff --git a/libs/compiler-rt/lib/builtins/emutls.c b/libs/compiler-rt/lib/builtins/emutls.c
new file mode 100644
index 00000000000..dcb3f7c43c2
--- /dev/null
+++ b/libs/compiler-rt/lib/builtins/emutls.c
@@ -0,0 +1,392 @@
+/* ===---------- emutls.c - Implements __emutls_get_address ---------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "int_lib.h"
+#include "int_util.h"
+
+#ifdef __BIONIC__
+/* There are 4 pthread key cleanup rounds on Bionic. Delay emutls deallocation
+   to round 2. We need to delay deallocation because:
+    - Android versions older than M lack __cxa_thread_atexit_impl, so apps
+      use a pthread key destructor to call C++ destructors.
+    - Apps might use __thread/thread_local variables in pthread destructors.
+   We can't wait until the final two rounds, because jemalloc needs two rounds
+   after the final malloc/free call to free its thread-specific data (see
+   https://reviews.llvm.org/D46978#1107507). */
+#define EMUTLS_SKIP_DESTRUCTOR_ROUNDS 1
+#else
+#define EMUTLS_SKIP_DESTRUCTOR_ROUNDS 0
+#endif
+
+typedef struct emutls_address_array {
+    uintptr_t skip_destructor_rounds;
+    uintptr_t size;  /* number of elements in the 'data' array */
+    void* data[];
+} emutls_address_array;
+
+static void emutls_shutdown(emutls_address_array *array);
+
+#ifndef _WIN32
+
+#include <pthread.h>
+
+static pthread_mutex_t emutls_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_key_t emutls_pthread_key;
+
+typedef unsigned int gcc_word __attribute__((mode(word)));
+typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
+
+/* Default is not to use posix_memalign, so systems like Android
+ * can use thread local data without heavier POSIX memory allocators.
+ */
+#ifndef EMUTLS_USE_POSIX_MEMALIGN
+#define EMUTLS_USE_POSIX_MEMALIGN 0
+#endif
+
+static __inline void *emutls_memalign_alloc(size_t align, size_t size) {
+    void *base;
+#if EMUTLS_USE_POSIX_MEMALIGN
+    if (posix_memalign(&base, align, size) != 0)
+        abort();
+#else
+    #define EXTRA_ALIGN_PTR_BYTES (align - 1 + sizeof(void*))
+    char* object;
+    if ((object = (char*)malloc(EXTRA_ALIGN_PTR_BYTES + size)) == NULL)
+        abort();
+    base = (void*)(((uintptr_t)(object + EXTRA_ALIGN_PTR_BYTES))
+                    & ~(uintptr_t)(align - 1));
+
+    ((void**)base)[-1] = object;
+#endif
+    return base;
+}
+
+static __inline void emutls_memalign_free(void *base) {
+#if EMUTLS_USE_POSIX_MEMALIGN
+    free(base);
+#else
+    /* The mallocated address is in ((void**)base)[-1] */
+    free(((void**)base)[-1]);
+#endif
+}
+
+static __inline void emutls_setspecific(emutls_address_array *value) {
+    pthread_setspecific(emutls_pthread_key, (void*) value);
+}
+
+static __inline emutls_address_array* emutls_getspecific() {
+    return (emutls_address_array*) pthread_getspecific(emutls_pthread_key);
+}
+
+static void emutls_key_destructor(void* ptr) {
+    emutls_address_array *array = (emutls_address_array*)ptr;
+    if (array->skip_destructor_rounds > 0) {
+        /* emutls is deallocated using a pthread key destructor. These
+         * destructors are called in several rounds to accommodate destructor
+         * functions that (re)initialize key values with pthread_setspecific.
+         * Delay the emutls deallocation to accommodate other end-of-thread
+         * cleanup tasks like calling thread_local destructors (e.g. the
+         * __cxa_thread_atexit fallback in libc++abi).
+         */
+        array->skip_destructor_rounds--;
+        emutls_setspecific(array);
+    } else {
+        emutls_shutdown(array);
+        free(ptr);
+    }
+}
+
+static __inline void emutls_init(void) {
+    if (pthread_key_create(&emutls_pthread_key, emutls_key_destructor) != 0)
+        abort();
+}
+
+static __inline void emutls_init_once(void) {
+    static pthread_once_t once = PTHREAD_ONCE_INIT;
+    pthread_once(&once, emutls_init);
+}
+
+static __inline void emutls_lock() {
+    pthread_mutex_lock(&emutls_mutex);
+}
+
+static __inline void emutls_unlock() {
+    pthread_mutex_unlock(&emutls_mutex);
+}
+
+#else /* _WIN32 */
+
+#include <windows.h>
+#include <malloc.h>
+#include <stdio.h>
+#include <assert.h>
+
+static LPCRITICAL_SECTION emutls_mutex;
+static DWORD emutls_tls_index = TLS_OUT_OF_INDEXES;
+
+typedef uintptr_t gcc_word;
+typedef void * gcc_pointer;
+
+static void win_error(DWORD last_err, const char *hint) {
+    char *buffer = NULL;
+    if (FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                       FORMAT_MESSAGE_FROM_SYSTEM |
+                       FORMAT_MESSAGE_MAX_WIDTH_MASK,
+                       NULL, last_err, 0, (LPSTR)&buffer, 1, NULL)) {
+        fprintf(stderr, "Windows error: %s\n", buffer);
+    } else {
+        fprintf(stderr, "Unkown Windows error: %s\n", hint);
+    }
+    LocalFree(buffer);
+}
+
+static __inline void win_abort(DWORD last_err, const char *hint) {
+    win_error(last_err, hint);
+    abort();
+}
+
+static __inline void *emutls_memalign_alloc(size_t align, size_t size) {
+    void *base = _aligned_malloc(size, align);
+    if (!base)
+        win_abort(GetLastError(), "_aligned_malloc");
+    return base;
+}
+
+static __inline void emutls_memalign_free(void *base) {
+    _aligned_free(base);
+}
+
+static void emutls_exit(void) {
+    if (emutls_mutex) {
+        DeleteCriticalSection(emutls_mutex);
+        _aligned_free(emutls_mutex);
+        emutls_mutex = NULL;
+    }
+    if (emutls_tls_index != TLS_OUT_OF_INDEXES) {
+        emutls_shutdown((emutls_address_array*)TlsGetValue(emutls_tls_index));
+        TlsFree(emutls_tls_index);
+        emutls_tls_index = TLS_OUT_OF_INDEXES;
+    }
+}
+
+#pragma warning (push)
+#pragma warning (disable : 4100)
+static BOOL CALLBACK emutls_init(PINIT_ONCE p0, PVOID p1, PVOID *p2) {
+    emutls_mutex = (LPCRITICAL_SECTION)_aligned_malloc(sizeof(CRITICAL_SECTION), 16);
+    if (!emutls_mutex) {
+        win_error(GetLastError(), "_aligned_malloc");
+        return FALSE;
+    }
+    InitializeCriticalSection(emutls_mutex);
+
+    emutls_tls_index = TlsAlloc();
+    if (emutls_tls_index == TLS_OUT_OF_INDEXES) {
+        emutls_exit();
+        win_error(GetLastError(), "TlsAlloc");
+        return FALSE;
+    }
+    atexit(&emutls_exit);
+    return TRUE;
+}
+
+static __inline void emutls_init_once(void) {
+    static INIT_ONCE once;
+    InitOnceExecuteOnce(&once, emutls_init, NULL, NULL);
+}
+
+static __inline void emutls_lock() {
+    EnterCriticalSection(emutls_mutex);
+}
+
+static __inline void emutls_unlock() {
+    LeaveCriticalSection(emutls_mutex);
+}
+
+static __inline void emutls_setspecific(emutls_address_array *value) {
+    if (TlsSetValue(emutls_tls_index, (LPVOID) value) == 0)
+        win_abort(GetLastError(), "TlsSetValue");
+}
+
+static __inline emutls_address_array* emutls_getspecific() {
+    LPVOID value = TlsGetValue(emutls_tls_index);
+    if (value == NULL) {
+        const DWORD err = GetLastError();
+        if (err != ERROR_SUCCESS)
+            win_abort(err, "TlsGetValue");
+    }
+    return (emutls_address_array*) value;
+}
+
+/* Provide atomic load/store functions for emutls_get_index if built with MSVC.
+ */
+#if !defined(__ATOMIC_RELEASE)
+#include <intrin.h>
+
+enum { __ATOMIC_ACQUIRE = 2, __ATOMIC_RELEASE = 3 };
+
+static __inline uintptr_t __atomic_load_n(void *ptr, unsigned type) {
+    assert(type == __ATOMIC_ACQUIRE);
+    // These return the previous value - but since we do an OR with 0,
+    // it's equivalent to a plain load.
+#ifdef _WIN64
+    return InterlockedOr64(ptr, 0);
+#else
+    return InterlockedOr(ptr, 0);
+#endif
+}
+
+static __inline void __atomic_store_n(void *ptr, uintptr_t val, unsigned type) {
+    assert(type == __ATOMIC_RELEASE);
+    InterlockedExchangePointer((void *volatile *)ptr, (void *)val);
+}
+
+#endif /* __ATOMIC_RELEASE */
+
+#pragma warning (pop)
+
+#endif /* _WIN32 */
+
+static size_t emutls_num_object = 0;  /* number of allocated TLS objects */
+
+/* Free the allocated TLS data
+ */
+static void emutls_shutdown(emutls_address_array *array) {
+    if (array) {
+        uintptr_t i;
+        for (i = 0; i < array->size; ++i) {
+            if (array->data[i])
+                emutls_memalign_free(array->data[i]);
+        }
+    }
+}
+
+/* For every TLS variable xyz,
+ * there is one __emutls_control variable named __emutls_v.xyz.
+ * If xyz has non-zero initial value, __emutls_v.xyz's "value"
+ * will point to __emutls_t.xyz, which has the initial value.
+ */
+typedef struct __emutls_control {
+    /* Must use gcc_word here, instead of size_t, to match GCC.  When
+       gcc_word is larger than size_t, the upper extra bits are all
+       zeros.  We can use variables of size_t to operate on size and
+       align.  */
+    gcc_word size;  /* size of the object in bytes */
+    gcc_word align;  /* alignment of the object in bytes */
+    union {
+        uintptr_t index;  /* data[index-1] is the object address */
+        void* address;  /* object address, when in single thread env */
+    } object;
+    void* value;  /* null or non-zero initial value for the object */
+} __emutls_control;
+
+/* Emulated TLS objects are always allocated at run-time. */
+static __inline void *emutls_allocate_object(__emutls_control *control) {
+    /* Use standard C types, check with gcc's emutls.o. */
+    COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(gcc_pointer));
+    COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(void*));
+
+    size_t size = control->size;
+    size_t align = control->align;
+    void* base;
+    if (align < sizeof(void*))
+        align = sizeof(void*);
+    /* Make sure that align is power of 2. */
+    if ((align & (align - 1)) != 0)
+        abort();
+
+    base = emutls_memalign_alloc(align, size);
+    if (control->value)
+        memcpy(base, control->value, size);
+    else
+        memset(base, 0, size);
+    return base;
+}
+
+
+/* Returns control->object.index; set index if not allocated yet. */
+static __inline uintptr_t emutls_get_index(__emutls_control *control) {
+    uintptr_t index = __atomic_load_n(&control->object.index, __ATOMIC_ACQUIRE);
+    if (!index) {
+        emutls_init_once();
+        emutls_lock();
+        index = control->object.index;
+        if (!index) {
+            index = ++emutls_num_object;
+            __atomic_store_n(&control->object.index, index, __ATOMIC_RELEASE);
+        }
+        emutls_unlock();
+    }
+    return index;
+}
+
+/* Updates newly allocated thread local emutls_address_array. */
+static __inline void emutls_check_array_set_size(emutls_address_array *array,
+                                                 uintptr_t size) {
+    if (array == NULL)
+        abort();
+    array->size = size;
+    emutls_setspecific(array);
+}
+
+/* Returns the new 'data' array size, number of elements,
+ * which must be no smaller than the given index.
+ */
+static __inline uintptr_t emutls_new_data_array_size(uintptr_t index) {
+   /* Need to allocate emutls_address_array with extra slots
+    * to store the header.
+    * Round up the emutls_address_array size to multiple of 16.
+    */
+    uintptr_t header_words = sizeof(emutls_address_array) / sizeof(void *);
+    return ((index + header_words + 15) & ~((uintptr_t)15)) - header_words;
+}
+
+/* Returns the size in bytes required for an emutls_address_array with
+ * N number of elements for data field.
+ */
+static __inline uintptr_t emutls_asize(uintptr_t N) {
+    return N * sizeof(void *) + sizeof(emutls_address_array);
+}
+
+/* Returns the thread local emutls_address_array.
+ * Extends its size if necessary to hold address at index.
+ */
+static __inline emutls_address_array *
+emutls_get_address_array(uintptr_t index) {
+    emutls_address_array* array = emutls_getspecific();
+    if (array == NULL) {
+        uintptr_t new_size = emutls_new_data_array_size(index);
+        array = (emutls_address_array*) malloc(emutls_asize(new_size));
+        if (array) {
+            memset(array->data, 0, new_size * sizeof(void*));
+            array->skip_destructor_rounds = EMUTLS_SKIP_DESTRUCTOR_ROUNDS;
+        }
+        emutls_check_array_set_size(array, new_size);
+    } else if (index > array->size) {
+        uintptr_t orig_size = array->size;
+        uintptr_t new_size = emutls_new_data_array_size(index);
+        array = (emutls_address_array*) realloc(array, emutls_asize(new_size));
+        if (array)
+            memset(array->data + orig_size, 0,
+                   (new_size - orig_size) * sizeof(void*));
+        emutls_check_array_set_size(array, new_size);
+    }
+    return array;
+}
+
+void* __emutls_get_address(void* control) {
+    uintptr_t index = emutls_get_index(control);
+    emutls_address_array* array = emutls_get_address_array(index--);
+    if (array->data[index] == NULL)
+        array->data[index] = emutls_allocate_object(control);
+    return array->data[index];
+}
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10160