[lsan] Factor pthread-specific assumptions out of thread tracking code

This is a small refactoring to prepare for porting LSan to Fuchsia.
Factor out parts of lsan_thread.{cpp,h} that don't apply to Fuchsia.
Since existing supported systems are POSIX-based, the affected code
is moved to lsan_posix.{cpp.h}.

Patch By: mcgrathr

Differential Revision: https://reviews.llvm.org/D73309

compiler-rt/lib/lsan/CMakeLists.txt

@@ -12,10 +12,11 @@ set(LSAN_COMMON_SOURCES
 set(LSAN_SOURCES
   lsan.cpp
   lsan_allocator.cpp
-  lsan_linux.cpp
   lsan_interceptors.cpp
+  lsan_linux.cpp
   lsan_mac.cpp
   lsan_malloc_mac.cpp
+  lsan_posix.cpp
   lsan_preinit.cpp
   lsan_thread.cpp
   )

compiler-rt/lib/lsan/lsan.cpp

@@ -114,10 +114,7 @@ extern "C" void __lsan_init() {
   InitializeInterceptors();
   InitializeThreadRegistry();
   InstallDeadlySignalHandlers(LsanOnDeadlySignal);
-  u32 tid = ThreadCreate(0, 0, true);
-  CHECK_EQ(tid, 0);
-  ThreadStart(tid, GetTid());
-  SetCurrentThread(tid);
+  InitializeMainThread();
 
   if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit)
     Atexit(DoLeakCheck);

compiler-rt/lib/lsan/lsan.h

@@ -12,6 +12,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "lsan_thread.h"
+#if SANITIZER_POSIX
+#include "lsan_posix.h"
+#endif
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
 

compiler-rt/lib/lsan/lsan_interceptors.cpp

@@ -22,7 +22,9 @@
 #include "sanitizer_common/sanitizer_platform_interceptors.h"
 #include "sanitizer_common/sanitizer_platform_limits_netbsd.h"
 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
+#if SANITIZER_POSIX
 #include "sanitizer_common/sanitizer_posix.h"
+#endif
 #include "sanitizer_common/sanitizer_tls_get_addr.h"
 #include "lsan.h"
 #include "lsan_allocator.h"
@@ -416,7 +418,6 @@ extern "C" void *__lsan_thread_start_func(void *arg) {
   int tid = 0;
   while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
     internal_sched_yield();
-  SetCurrentThread(tid);
   ThreadStart(tid, GetTid());
   atomic_store(&p->tid, 0, memory_order_release);
   return callback(param);

compiler-rt/lib/lsan/lsan_posix.cpp

@@ -0,0 +1,85 @@
+//=-- lsan_posix.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+//
+// This file is a part of LeakSanitizer.
+// Standalone LSan RTL code common to POSIX-like systems.
+//
+//===---------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+
+#if SANITIZER_POSIX
+#include "lsan.h"
+#include "lsan_allocator.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+#include "sanitizer_common/sanitizer_tls_get_addr.h"
+
+namespace __lsan {
+
+ThreadContext::ThreadContext(int tid) : ThreadContextLsanBase(tid) {}
+
+struct OnStartedArgs {
+  uptr stack_begin;
+  uptr stack_end;
+  uptr cache_begin;
+  uptr cache_end;
+  uptr tls_begin;
+  uptr tls_end;
+  DTLS *dtls;
+};
+
+void ThreadContext::OnStarted(void *arg) {
+  auto args = reinterpret_cast<const OnStartedArgs *>(arg);
+  stack_begin_ = args->stack_begin;
+  stack_end_ = args->stack_end;
+  tls_begin_ = args->tls_begin;
+  tls_end_ = args->tls_end;
+  cache_begin_ = args->cache_begin;
+  cache_end_ = args->cache_end;
+  dtls_ = args->dtls;
+}
+
+void ThreadStart(u32 tid, tid_t os_id, ThreadType thread_type) {
+  OnStartedArgs args;
+  uptr stack_size = 0;
+  uptr tls_size = 0;
+  GetThreadStackAndTls(tid == 0, &args.stack_begin, &stack_size,
+                       &args.tls_begin, &tls_size);
+  args.stack_end = args.stack_begin + stack_size;
+  args.tls_end = args.tls_begin + tls_size;
+  GetAllocatorCacheRange(&args.cache_begin, &args.cache_end);
+  args.dtls = DTLS_Get();
+  ThreadContextLsanBase::ThreadStart(tid, os_id, thread_type, &args);
+}
+
+bool GetThreadRangesLocked(tid_t os_id, uptr *stack_begin, uptr *stack_end,
+                           uptr *tls_begin, uptr *tls_end, uptr *cache_begin,
+                           uptr *cache_end, DTLS **dtls) {
+  ThreadContext *context = static_cast<ThreadContext *>(
+      GetThreadRegistryLocked()->FindThreadContextByOsIDLocked(os_id));
+  if (!context)
+    return false;
+  *stack_begin = context->stack_begin();
+  *stack_end = context->stack_end();
+  *tls_begin = context->tls_begin();
+  *tls_end = context->tls_end();
+  *cache_begin = context->cache_begin();
+  *cache_end = context->cache_end();
+  *dtls = context->dtls();
+  return true;
+}
+
+void InitializeMainThread() {
+  u32 tid = ThreadCreate(0, 0, true);
+  CHECK_EQ(tid, 0);
+  ThreadStart(tid, GetTid());
+}
+
+}  // namespace __lsan
+
+#endif  // SANITIZER_POSIX

compiler-rt/lib/lsan/lsan_posix.h

@@ -0,0 +1,49 @@
+//=-- lsan_posix.h -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+//
+// This file is a part of LeakSanitizer.
+// Standalone LSan RTL code common to POSIX-like systems.
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef LSAN_POSIX_H
+#define LSAN_POSIX_H
+
+#include "lsan_thread.h"
+#include "sanitizer_common/sanitizer_platform.h"
+
+#if !SANITIZER_POSIX
+#error "lsan_posix.h is used only on POSIX-like systems (SANITIZER_POSIX)"
+#endif
+
+namespace __sanitizer {
+struct DTLS;
+}
+
+namespace __lsan {
+
+class ThreadContext : public ThreadContextLsanBase {
+ public:
+  explicit ThreadContext(int tid);
+  void OnStarted(void *arg) override;
+  uptr tls_begin() { return tls_begin_; }
+  uptr tls_end() { return tls_end_; }
+  DTLS *dtls() { return dtls_; }
+
+ private:
+  uptr tls_begin_ = 0;
+  uptr tls_end_ = 0;
+  DTLS *dtls_ = nullptr;
+};
+
+void ThreadStart(u32 tid, tid_t os_id,
+                 ThreadType thread_type = ThreadType::Regular);
+
+}  // namespace __lsan
+
+#endif  // LSAN_POSIX_H

compiler-rt/lib/lsan/lsan_thread.cpp

@@ -13,12 +13,13 @@
 
 #include "lsan_thread.h"
 
+#include "lsan.h"
+#include "lsan_allocator.h"
+#include "lsan_common.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_placement_new.h"
 #include "sanitizer_common/sanitizer_thread_registry.h"
 #include "sanitizer_common/sanitizer_tls_get_addr.h"
-#include "lsan_allocator.h"
-#include "lsan_common.h"
 
 namespace __lsan {
 
@@ -26,7 +27,7 @@ static ThreadRegistry *thread_registry;
 
 static ThreadContextBase *CreateThreadContext(u32 tid) {
   void *mem = MmapOrDie(sizeof(ThreadContext), "ThreadContext");
-  return new(mem) ThreadContext(tid);
+  return new (mem) ThreadContext(tid);
 }
 
 static const uptr kMaxThreads = 1 << 13;
@@ -34,59 +35,26 @@ static const uptr kThreadQuarantineSize = 64;
 
 void InitializeThreadRegistry() {
   static ALIGNED(64) char thread_registry_placeholder[sizeof(ThreadRegistry)];
-  thread_registry = new(thread_registry_placeholder)
-    ThreadRegistry(CreateThreadContext, kMaxThreads, kThreadQuarantineSize);
+  thread_registry = new (thread_registry_placeholder)
+      ThreadRegistry(CreateThreadContext, kMaxThreads, kThreadQuarantineSize);
 }
 
-ThreadContext::ThreadContext(int tid)
-    : ThreadContextBase(tid),
-      stack_begin_(0),
-      stack_end_(0),
-      cache_begin_(0),
-      cache_end_(0),
-      tls_begin_(0),
-      tls_end_(0),
-      dtls_(nullptr) {}
+ThreadContextLsanBase::ThreadContextLsanBase(int tid)
+    : ThreadContextBase(tid) {}
 
-struct OnStartedArgs {
-  uptr stack_begin, stack_end,
-       cache_begin, cache_end,
-       tls_begin, tls_end;
-  DTLS *dtls;
-};
-
-void ThreadContext::OnStarted(void *arg) {
-  OnStartedArgs *args = reinterpret_cast<OnStartedArgs *>(arg);
-  stack_begin_ = args->stack_begin;
-  stack_end_ = args->stack_end;
-  tls_begin_ = args->tls_begin;
-  tls_end_ = args->tls_end;
-  cache_begin_ = args->cache_begin;
-  cache_end_ = args->cache_end;
-  dtls_ = args->dtls;
-}
-
-void ThreadContext::OnFinished() {
+void ThreadContextLsanBase::OnFinished() {
   AllocatorThreadFinish();
   DTLS_Destroy();
 }
 
-u32 ThreadCreate(u32 parent_tid, uptr user_id, bool detached) {
-  return thread_registry->CreateThread(user_id, detached, parent_tid,
-                                       /* arg */ nullptr);
+u32 ThreadCreate(u32 parent_tid, uptr user_id, bool detached, void *arg) {
+  return thread_registry->CreateThread(user_id, detached, parent_tid, arg);
 }
 
-void ThreadStart(u32 tid, tid_t os_id, ThreadType thread_type) {
-  OnStartedArgs args;
-  uptr stack_size = 0;
-  uptr tls_size = 0;
-  GetThreadStackAndTls(tid == 0, &args.stack_begin, &stack_size,
-                       &args.tls_begin, &tls_size);
-  args.stack_end = args.stack_begin + stack_size;
-  args.tls_end = args.tls_begin + tls_size;
-  GetAllocatorCacheRange(&args.cache_begin, &args.cache_end);
-  args.dtls = DTLS_Get();
-  thread_registry->StartThread(tid, os_id, thread_type, &args);
+void ThreadContextLsanBase::ThreadStart(u32 tid, tid_t os_id,
+                                        ThreadType thread_type, void *arg) {
+  thread_registry->StartThread(tid, os_id, thread_type, arg);
+  SetCurrentThread(tid);
 }
 
 void ThreadFinish() {
@@ -95,7 +63,8 @@ void ThreadFinish() {
 }
 
 ThreadContext *CurrentThreadContext() {
-  if (!thread_registry) return nullptr;
+  if (!thread_registry)
+    return nullptr;
   if (GetCurrentThread() == kInvalidTid)
     return nullptr;
   // No lock needed when getting current thread.
@@ -111,12 +80,12 @@ static bool FindThreadByUid(ThreadContextBase *tctx, void *arg) {
 }
 
 u32 ThreadTid(uptr uid) {
-  return thread_registry->FindThread(FindThreadByUid, (void*)uid);
+  return thread_registry->FindThread(FindThreadByUid, (void *)uid);
 }
 
 void ThreadJoin(u32 tid) {
   CHECK_NE(tid, kInvalidTid);
-  thread_registry->JoinThread(tid, /* arg */nullptr);
+  thread_registry->JoinThread(tid, /* arg */ nullptr);
 }
 
 void EnsureMainThreadIDIsCorrect() {
@@ -126,37 +95,16 @@ void EnsureMainThreadIDIsCorrect() {
 
 ///// Interface to the common LSan module. /////
 
-bool GetThreadRangesLocked(tid_t os_id, uptr *stack_begin, uptr *stack_end,
-                           uptr *tls_begin, uptr *tls_end, uptr *cache_begin,
-                           uptr *cache_end, DTLS **dtls) {
-  ThreadContext *context = static_cast<ThreadContext *>(
-      thread_registry->FindThreadContextByOsIDLocked(os_id));
-  if (!context) return false;
-  *stack_begin = context->stack_begin();
-  *stack_end = context->stack_end();
-  *tls_begin = context->tls_begin();
-  *tls_end = context->tls_end();
-  *cache_begin = context->cache_begin();
-  *cache_end = context->cache_end();
-  *dtls = context->dtls();
-  return true;
-}
-
 void ForEachExtraStackRange(tid_t os_id, RangeIteratorCallback callback,
-                            void *arg) {
-}
+                            void *arg) {}
 
-void LockThreadRegistry() {
-  thread_registry->Lock();
-}
+void LockThreadRegistry() { thread_registry->Lock(); }
 
-void UnlockThreadRegistry() {
-  thread_registry->Unlock();
-}
+void UnlockThreadRegistry() { thread_registry->Unlock(); }
 
 ThreadRegistry *GetThreadRegistryLocked() {
   thread_registry->CheckLocked();
   return thread_registry;
 }
 
-} // namespace __lsan
+}  // namespace __lsan

compiler-rt/lib/lsan/lsan_thread.h

@@ -16,38 +16,36 @@
 
 #include "sanitizer_common/sanitizer_thread_registry.h"
 
-namespace __sanitizer {
-struct DTLS;
-}
-
 namespace __lsan {
 
-class ThreadContext : public ThreadContextBase {
+class ThreadContextLsanBase : public ThreadContextBase {
  public:
-  explicit ThreadContext(int tid);
-  void OnStarted(void *arg) override;
+  explicit ThreadContextLsanBase(int tid);
   void OnFinished() override;
   uptr stack_begin() { return stack_begin_; }
   uptr stack_end() { return stack_end_; }
-  uptr tls_begin() { return tls_begin_; }
-  uptr tls_end() { return tls_end_; }
   uptr cache_begin() { return cache_begin_; }
   uptr cache_end() { return cache_end_; }
-  DTLS *dtls() { return dtls_; }
 
- private:
-  uptr stack_begin_, stack_end_,
-       cache_begin_, cache_end_,
-       tls_begin_, tls_end_;
-  DTLS *dtls_;
+  // The argument is passed on to the subclass's OnStarted member function.
+  static void ThreadStart(u32 tid, tid_t os_id, ThreadType thread_type,
+                          void *onstarted_arg);
+
+ protected:
+  uptr stack_begin_ = 0;
+  uptr stack_end_ = 0;
+  uptr cache_begin_ = 0;
+  uptr cache_end_ = 0;
 };
 
-void InitializeThreadRegistry();
+// This subclass of ThreadContextLsanBase is declared in an OS-specific header.
+class ThreadContext;
 
-void ThreadStart(u32 tid, tid_t os_id,
-                 ThreadType thread_type = ThreadType::Regular);
+void InitializeThreadRegistry();
+void InitializeMainThread();
+
+u32 ThreadCreate(u32 tid, uptr uid, bool detached, void *arg = nullptr);
 void ThreadFinish();
-u32 ThreadCreate(u32 tid, uptr uid, bool detached);
 void ThreadJoin(u32 tid);
 u32 ThreadTid(uptr uid);
 
@@ -55,6 +53,7 @@ u32 GetCurrentThread();
 void SetCurrentThread(u32 tid);
 ThreadContext *CurrentThreadContext();
 void EnsureMainThreadIDIsCorrect();
+
 }  // namespace __lsan
 
 #endif  // LSAN_THREAD_H