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stdlib: generalise TLS to support Windows #11949

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Merged
merged 1 commit into from
Sep 18, 2017
Merged

stdlib: generalise TLS to support Windows #11949

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24 changes: 12 additions & 12 deletions stdlib/public/SwiftShims/LibcShims.h
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Original file line number Diff line number Diff line change
Expand Up @@ -114,28 +114,28 @@ double _swift_stdlib_squareRoot(double _self) {
// TLS - thread local storage

#if defined(__ANDROID__)
typedef int __swift_pthread_key_t;
typedef int __swift_thread_key_t;
#elif defined(__linux__)
typedef unsigned int __swift_pthread_key_t;
typedef unsigned int __swift_thread_key_t;
#elif defined(__FreeBSD__)
typedef int __swift_pthread_key_t;
typedef int __swift_thread_key_t;
#elif defined(_WIN32)
typedef unsigned long __swift_thread_key_t;
#else
typedef unsigned long __swift_pthread_key_t;
typedef unsigned long __swift_thread_key_t;
#endif

SWIFT_RUNTIME_STDLIB_INTERFACE
int _swift_stdlib_pthread_key_create(
__swift_pthread_key_t * _Nonnull key, void
(* _Nullable destructor)(void * _Nullable )
);
int
_swift_stdlib_thread_key_create(__swift_thread_key_t * _Nonnull key,
void (* _Nullable destructor)(void * _Nullable));

SWIFT_RUNTIME_STDLIB_INTERFACE
void * _Nullable _swift_stdlib_pthread_getspecific(__swift_pthread_key_t key);
void * _Nullable _swift_stdlib_thread_getspecific(__swift_thread_key_t key);

SWIFT_RUNTIME_STDLIB_INTERFACE
int _swift_stdlib_pthread_setspecific(
__swift_pthread_key_t key, const void * _Nullable value
);
int _swift_stdlib_thread_setspecific(__swift_thread_key_t key,
const void * _Nullable value);

// TODO: Remove horrible workaround when importer does Float80 <-> long double.
#if (defined __i386__ || defined __x86_64__) && !defined _MSC_VER
Expand Down
14 changes: 7 additions & 7 deletions stdlib/public/core/ThreadLocalStorage.swift
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Expand Up @@ -64,7 +64,7 @@ internal struct _ThreadLocalStorage {
static internal func getPointer()
-> UnsafeMutablePointer<_ThreadLocalStorage>
{
let tlsRawPtr = _swift_stdlib_pthread_getspecific(_tlsKey)
let tlsRawPtr = _swift_stdlib_thread_getspecific(_tlsKey)
if _fastPath(tlsRawPtr != nil) {
return tlsRawPtr._unsafelyUnwrappedUnchecked.assumingMemoryBound(
to: _ThreadLocalStorage.self)
Expand Down Expand Up @@ -116,10 +116,10 @@ internal func _destroyTLS(_ ptr: UnsafeMutableRawPointer?) {
}

// Lazily created global key for use with pthread TLS
internal let _tlsKey: __swift_pthread_key_t = {
let sentinelValue = __swift_pthread_key_t.max
var key: __swift_pthread_key_t = sentinelValue
let success = _swift_stdlib_pthread_key_create(&key, _destroyTLS)
internal let _tlsKey: __swift_thread_key_t = {
let sentinelValue = __swift_thread_key_t.max
var key: __swift_thread_key_t = sentinelValue
let success = _swift_stdlib_thread_key_create(&key, _destroyTLS)
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Is there a way to change the calling convention for _destroyTLS? On Windows (x86), this should be a __stdcall function.

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I don't think the Swift compiler can manipulate Windows calling conventions yet. It should be straightforward to rewrite _destroyTLS in C, or write a C __stdcall function that calls back into Swift.

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We could introduce a @_callingconv attribute. But, it sounds like it would be easier to move it to swift-shims and rewrite it in C.

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A shim that calls back into the stdlib for deinitialization would be my preferred approach. We have non-trivial deinitialization logic that ideally would be kept in Swift. We likewise probably want allocate/deallocate parity, and Swift knows the sizes of the TLS buffer already.

_sanityCheck(success == 0, "somehow failed to create TLS key")
_sanityCheck(key != sentinelValue, "Didn't make a new key")
return key
Expand All @@ -129,7 +129,7 @@ internal let _tlsKey: __swift_pthread_key_t = {
internal func _initializeThreadLocalStorage()
-> UnsafeMutablePointer<_ThreadLocalStorage>
{
_sanityCheck(_swift_stdlib_pthread_getspecific(_tlsKey) == nil,
_sanityCheck(_swift_stdlib_thread_getspecific(_tlsKey) == nil,
"already initialized")

// Create and initialize one.
Expand All @@ -146,7 +146,7 @@ internal func _initializeThreadLocalStorage()
tlsPtr.initialize(
to: _ThreadLocalStorage(_uBreakIterator: newUBreakIterator)
)
let success = _swift_stdlib_pthread_setspecific(_tlsKey, tlsPtr)
let success = _swift_stdlib_thread_setspecific(_tlsKey, tlsPtr)
_sanityCheck(success == 0, "setspecific failed")
return tlsPtr
}
Expand Down
53 changes: 39 additions & 14 deletions stdlib/public/stubs/LibcShims.cpp
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Expand Up @@ -15,10 +15,12 @@
#include <cmath>
#if defined(_WIN32)
#include <io.h>
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#else
#include <unistd.h>
#endif
#include <pthread.h>
#endif

#include <stdlib.h>
#include <stdio.h>
Expand Down Expand Up @@ -60,7 +62,7 @@ __swift_size_t swift::_swift_stdlib_strlen(const char *s) {

SWIFT_RUNTIME_STDLIB_INTERFACE
__swift_size_t swift::_swift_stdlib_strlen_unsigned(const unsigned char *s) {
return strlen((char *)s);
return strlen(reinterpret_cast<const char *>(s));
}

SWIFT_RUNTIME_STDLIB_INTERFACE
Expand Down Expand Up @@ -98,34 +100,57 @@ int swift::_swift_stdlib_close(int fd) {
#endif
}

// Guard compilation on the typedef for __swift_pthread_key_t in LibcShims.h
#if defined(_WIN32)
static_assert(std::is_same<__swift_thread_key_t, DWORD>::value,
"__swift_thread_key_t is not a DWORD");

SWIFT_RUNTIME_STDLIB_INTERFACE
int
swift::_swift_stdlib_thread_key_create(__swift_thread_key_t * _Nonnull key,
void (* _Nullable destructor)(void *)) {
// TODO(compnerd) account for x86 CC violation (__stdcall)
*key = FlsAlloc(reinterpret_cast<PFLS_CALLBACK_FUNCTION>(destructor));
return *key != FLS_OUT_OF_INDEXES;
}

SWIFT_RUNTIME_STDLIB_INTERFACE
void * _Nullable
swift::_swift_stdlib_thread_getspecific(__swift_thread_key_t key) {
return FlsGetValue(key);
}

SWIFT_RUNTIME_STDLIB_INTERFACE
int swift::_swift_stdlib_thread_setspecific(__swift_thread_key_t key,
const void * _Nullable value) {
return FlsSetValue(key, const_cast<void *>(value)) == TRUE;
}
#else
// Guard compilation on the typedef for __swift_thread_key_t in LibcShims.h
// being identical to the platform's pthread_key_t
static_assert(std::is_same<__swift_pthread_key_t, pthread_key_t>::value,
static_assert(std::is_same<__swift_thread_key_t, pthread_key_t>::value,
"This platform's pthread_key_t differs. If you hit this assert, "
"fix __swift_pthread_key_t's typedef in LibcShims.h by adding an "
"#if guard and definition for your platform");

SWIFT_RUNTIME_STDLIB_INTERFACE
int swift::_swift_stdlib_pthread_key_create(
__swift_pthread_key_t * _Nonnull key,
void (* _Nullable destructor)(void *)
) {
int
swift::_swift_stdlib_thread_key_create(__swift_thread_key_t * _Nonnull key,
void (* _Nullable destructor)(void *)) {
return pthread_key_create(key, destructor);
}

SWIFT_RUNTIME_STDLIB_INTERFACE
void * _Nullable swift::_swift_stdlib_pthread_getspecific(
__swift_pthread_key_t key
) {
void * _Nullable
swift::_swift_stdlib_thread_getspecific(__swift_thread_key_t key) {
return pthread_getspecific(key);
}

SWIFT_RUNTIME_STDLIB_INTERFACE
int swift::_swift_stdlib_pthread_setspecific(
__swift_pthread_key_t key, const void * _Nullable value
) {
int swift::_swift_stdlib_thread_setspecific(__swift_thread_key_t key,
const void * _Nullable value) {
return pthread_setspecific(key, value);
}
#endif

#if defined(__APPLE__)
#include <malloc/malloc.h>
Expand Down