Revert r301089 "[builtins] Implement emulated TLS on Windows."

This broke the self-host build on Windows (PR32777).

Original commit message:

> [builtins] Implement emulated TLS on Windows.
>
> Summary:
> LLVM JIT needs to be able to use emulated TLS on all platforms, and this provides a reference one can compile to enable emutls for Linux/Mac/Windows.
>
> Reviewers: chh, howard.hinnant
>
> Reviewed By: chh
>
> Subscribers: mgorny, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D30787

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@301274 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 67 insertions, 222 deletions

diff --git a/lib/builtins/CMakeLists.txt b/lib/builtins/CMakeLists.txt
index c30d9b363..161487e70 100644
--- a/lib/builtins/CMakeLists.txt
+++ b/lib/builtins/CMakeLists.txt
@@ -164,8 +164,7 @@ set(GENERIC_SOURCES
   udivti3.c
   umoddi3.c
   umodsi3.c
-  umodti3.c
-  emutls.c)
+  umodti3.c)
 
 option(COMPILER_RT_EXCLUDE_ATOMIC_BUILTIN
   "Skip the atomic builtin (this may be needed if system headers are unavailable)"
@@ -188,6 +187,12 @@ if(APPLE)
     atomic_thread_fence.c)
 endif()
 
+if(NOT WIN32 OR MINGW)
+  set(GENERIC_SOURCES
+      ${GENERIC_SOURCES}
+      emutls.c)
+endif()
+
 if (HAVE_UNWIND_H)
   set(GENERIC_SOURCES
       ${GENERIC_SOURCES}
diff --git a/lib/builtins/emutls.c b/lib/builtins/emutls.c
index c884e9040..eccbf5336 100644
--- a/lib/builtins/emutls.c
+++ b/lib/builtins/emutls.c
@@ -7,7 +7,7 @@
  *
  * ===----------------------------------------------------------------------===
  */
-
+#include <pthread.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -15,23 +15,6 @@
 #include "int_lib.h"
 #include "int_util.h"
 
-typedef struct emutls_address_array {
-    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.
  */
@@ -39,6 +22,26 @@ typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
 #define EMUTLS_USE_POSIX_MEMALIGN 0
 #endif
 
+/* 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 unsigned int gcc_word __attribute__((mode(word)));
+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;
+
 static __inline void *emutls_memalign_alloc(size_t align, size_t size) {
     void *base;
 #if EMUTLS_USE_POSIX_MEMALIGN
@@ -47,7 +50,7 @@ static __inline void *emutls_memalign_alloc(size_t align, size_t size) {
 #else
     #define EXTRA_ALIGN_PTR_BYTES (align - 1 + sizeof(void*))
     char* object;
-    if ((object = (char*)malloc(EXTRA_ALIGN_PTR_BYTES + size)) == NULL)
+    if ((object = malloc(EXTRA_ALIGN_PTR_BYTES + size)) == NULL)
         abort();
     base = (void*)(((uintptr_t)(object + EXTRA_ALIGN_PTR_BYTES))
                     & ~(uintptr_t)(align - 1));
@@ -66,192 +69,10 @@ static __inline void emutls_memalign_free(void *base) {
 #endif
 }
 
-static void emutls_key_destructor(void* ptr) {
-    emutls_shutdown((emutls_address_array*)ptr);
-    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);
-}
-
-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);
-}
-
-#else
-
-#include <Windows.h>
-#include <malloc.h>
-#include <stdio.h>
-#include <assert.h>
-#include <immintrin.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;
-}
-
-enum { __ATOMIC_ACQUIRE, __ATOMIC_RELEASE };
-
-static __inline uintptr_t __atomic_load_n(void *ptr, unsigned type) {
-    assert(type == __ATOMIC_ACQUIRE);
-    return (uintptr_t) _load_be_u64(ptr);
-}
-
-static __inline void __atomic_store_n(void *ptr, uintptr_t val, unsigned type) {
-    assert(type == __ATOMIC_RELEASE);
-    _store_be_u64(ptr, val);
-}
-#pragma warning (pop)
-
-#endif
-
-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. */
+    typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
     COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(gcc_pointer));
     COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(void*));
 
@@ -272,19 +93,45 @@ static __inline void *emutls_allocate_object(__emutls_control *control) {
     return base;
 }
 
+static pthread_mutex_t emutls_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static size_t emutls_num_object = 0;  /* number of allocated TLS objects */
+
+typedef struct emutls_address_array {
+    uintptr_t size;  /* number of elements in the 'data' array */
+    void* data[];
+} emutls_address_array;
+
+static pthread_key_t emutls_pthread_key;
+
+static void emutls_key_destructor(void* ptr) {
+    emutls_address_array* array = (emutls_address_array*)ptr;
+    uintptr_t i;
+    for (i = 0; i < array->size; ++i) {
+        if (array->data[i])
+            emutls_memalign_free(array->data[i]);
+    }
+    free(ptr);
+}
+
+static void emutls_init(void) {
+    if (pthread_key_create(&emutls_pthread_key, emutls_key_destructor) != 0)
+        abort();
+}
 
 /* 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();
+        static pthread_once_t once = PTHREAD_ONCE_INIT;
+        pthread_once(&once, emutls_init);
+        pthread_mutex_lock(&emutls_mutex);
         index = control->object.index;
         if (!index) {
             index = ++emutls_num_object;
             __atomic_store_n(&control->object.index, index, __ATOMIC_RELEASE);
         }
-        emutls_unlock();
+        pthread_mutex_unlock(&emutls_mutex);
     }
     return index;
 }
@@ -295,7 +142,7 @@ static __inline void emutls_check_array_set_size(emutls_address_array *array,
     if (array == NULL)
         abort();
     array->size = size;
-    emutls_setspecific(array);
+    pthread_setspecific(emutls_pthread_key, (void*)array);
 }
 
 /* Returns the new 'data' array size, number of elements,
@@ -309,29 +156,22 @@ static __inline uintptr_t emutls_new_data_array_size(uintptr_t index) {
     return ((index + 1 + 15) & ~((uintptr_t)15)) - 1;
 }
 
-/* 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();
+    emutls_address_array* array = pthread_getspecific(emutls_pthread_key);
     if (array == NULL) {
         uintptr_t new_size = emutls_new_data_array_size(index);
-        array = (emutls_address_array*) malloc(emutls_asize(new_size));
+        array = malloc(new_size * sizeof(void *) + sizeof(emutls_address_array));
         if (array)
             memset(array->data, 0, new_size * sizeof(void*));
         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));
+        array = realloc(array, new_size * sizeof(void *) + sizeof(emutls_address_array));
         if (array)
             memset(array->data + orig_size, 0,
                    (new_size - orig_size) * sizeof(void*));
@@ -342,8 +182,8 @@ emutls_get_address_array(uintptr_t index) {
 
 void* __emutls_get_address(__emutls_control* 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];
+    emutls_address_array* array = emutls_get_address_array(index);
+    if (array->data[index - 1] == NULL)
+        array->data[index - 1] = emutls_allocate_object(control);
+    return array->data[index - 1];
 }