Revert "[sanitizer] Simplify GetTls with dl_iterate_phdr"

This reverts commit 9be8f8b.
This breaks tsan on Ubuntu 16.04:

    $ cat tiny_race.c
    #include <pthread.h>
    int Global;
    void *Thread1(void *x) {
      Global = 42;
      return x;
    }
    int main() {
      pthread_t t;
      pthread_create(&t, NULL, Thread1, NULL);
      Global = 43;
      pthread_join(t, NULL);
      return Global;
    }
    $ out/gn/bin/clang -fsanitize=thread -g -O1 tiny_race.c --sysroot ~/src/chrome/src/build/linux/debian_sid_amd64-sysroot/
    $ docker run -v $PWD:/foo ubuntu:xenial /foo/a.out
    FATAL: ThreadSanitizer CHECK failed: ../../compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:447 "((thr_beg)) >= ((tls_addr))" (0x7fddd76beb80, 0xfffffffffffff980)
        #0 <null> <null> (a.out+0x4960b6)
        #1 <null> <null> (a.out+0x4b677f)
        rust-lang#2 <null> <null> (a.out+0x49cf94)
        rust-lang#3 <null> <null> (a.out+0x499bd2)
        rust-lang#4 <null> <null> (a.out+0x42aaf1)
        rust-lang#5 <null> <null> (libpthread.so.0+0x76b9)
        rust-lang#6 <null> <null> (libc.so.6+0x1074dc)

(Get the sysroot from here: https://commondatastorage.googleapis.com/chrome-linux-sysroot/toolchain/500976182686961e34974ea7bdc0a21fca32be06/debian_sid_amd64_sysroot.tar.xz)

Also reverts follow-on commits:
This reverts commit 58c62fd.
This reverts commit 31e541e.

compiler-rt/lib/asan/asan_rtl.cpp

@@ -490,6 +490,9 @@ static void AsanInitInternal() {
   if (flags()->start_deactivated)
     AsanDeactivate();
 
+  // interceptors
+  InitTlsSize();
+
   // Create main thread.
   AsanThread *main_thread = CreateMainThread();
   CHECK_EQ(0, main_thread->tid());
@@ -565,7 +568,7 @@ void UnpoisonStack(uptr bottom, uptr top, const char *type) {
         type, top, bottom, top - bottom, top - bottom);
     return;
   }
-  PoisonShadow(bottom, RoundUpTo(top - bottom, SHADOW_GRANULARITY), 0);
+  PoisonShadow(bottom, top - bottom, 0);
 }
 
 static void UnpoisonDefaultStack() {

compiler-rt/lib/asan/asan_thread.cpp

@@ -307,7 +307,7 @@ void AsanThread::SetThreadStackAndTls(const InitOptions *options) {
   uptr stack_size = 0;
   GetThreadStackAndTls(tid() == 0, &stack_bottom_, &stack_size, &tls_begin_,
                        &tls_size);
-  stack_top_ = RoundDownTo(stack_bottom_ + stack_size, SHADOW_GRANULARITY);
+  stack_top_ = stack_bottom_ + stack_size;
   tls_end_ = tls_begin_ + tls_size;
   dtls_ = DTLS_Get();
 

compiler-rt/lib/hwasan/hwasan.cpp

@@ -265,6 +265,8 @@ void __hwasan_init() {
   hwasan_init_is_running = 1;
   SanitizerToolName = "HWAddressSanitizer";
 
+  InitTlsSize();
+
   CacheBinaryName();
   InitializeFlags();
 

compiler-rt/lib/lsan/lsan.cpp

@@ -98,6 +98,7 @@ extern "C" void __lsan_init() {
   InitCommonLsan();
   InitializeAllocator();
   ReplaceSystemMalloc();
+  InitTlsSize();
   InitializeInterceptors();
   InitializeThreadRegistry();
   InstallDeadlySignalHandlers(LsanOnDeadlySignal);

compiler-rt/lib/memprof/memprof_rtl.cpp

@@ -214,6 +214,9 @@ static void MemprofInitInternal() {
 
   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
 
+  // interceptors
+  InitTlsSize();
+
   // Create main thread.
   MemprofThread *main_thread = CreateMainThread();
   CHECK_EQ(0, main_thread->tid());

compiler-rt/lib/msan/msan.cpp

@@ -436,6 +436,7 @@ void __msan_init() {
 
   InitializeInterceptors();
   CheckASLR();
+  InitTlsSize();
   InstallDeadlySignalHandlers(MsanOnDeadlySignal);
   InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
 

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -284,6 +284,7 @@ void SetSandboxingCallback(void (*f)());
 
 void InitializeCoverage(bool enabled, const char *coverage_dir);
 
+void InitTlsSize();
 uptr GetTlsSize();
 
 // Other

compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cpp

@@ -103,6 +103,7 @@ void DisableCoreDumperIfNecessary() {}
 void InstallDeadlySignalHandlers(SignalHandlerType handler) {}
 void SetAlternateSignalStack() {}
 void UnsetAlternateSignalStack() {}
+void InitTlsSize() {}
 
 bool SignalContext::IsStackOverflow() const { return false; }
 void SignalContext::DumpAllRegisters(void *context) { UNIMPLEMENTED(); }

compiler-rt/lib/sanitizer_common/sanitizer_linux.h

@@ -98,6 +98,7 @@ class ThreadLister {
 // Exposed for testing.
 uptr ThreadDescriptorSize();
 uptr ThreadSelf();
+uptr ThreadSelfOffset();
 
 // Matches a library's file name against a base name (stripping path and version
 // information).

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

@@ -188,8 +188,80 @@ __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
 #endif
 }
 
-// ThreadDescriptorSize() is only used by lsan to get the pointer to
-// thread-specific data keys in the thread control block.
+#if SANITIZER_GLIBC && !SANITIZER_GO
+static uptr g_tls_size;
+
+#ifdef __i386__
+#define CHECK_GET_TLS_STATIC_INFO_VERSION (!__GLIBC_PREREQ(2, 27))
+#else
+#define CHECK_GET_TLS_STATIC_INFO_VERSION 0
+#endif
+
+#if CHECK_GET_TLS_STATIC_INFO_VERSION
+#define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
+#else
+#define DL_INTERNAL_FUNCTION
+#endif
+
+namespace {
+struct GetTlsStaticInfoCall {
+  typedef void (*get_tls_func)(size_t*, size_t*);
+};
+struct GetTlsStaticInfoRegparmCall {
+  typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
+};
+
+template <typename T>
+void CallGetTls(void* ptr, size_t* size, size_t* align) {
+  typename T::get_tls_func get_tls;
+  CHECK_EQ(sizeof(get_tls), sizeof(ptr));
+  internal_memcpy(&get_tls, &ptr, sizeof(ptr));
+  CHECK_NE(get_tls, 0);
+  get_tls(size, align);
+}
+
+bool CmpLibcVersion(int major, int minor, int patch) {
+  int ma;
+  int mi;
+  int pa;
+  if (!GetLibcVersion(&ma, &mi, &pa))
+    return false;
+  if (ma > major)
+    return true;
+  if (ma < major)
+    return false;
+  if (mi > minor)
+    return true;
+  if (mi < minor)
+    return false;
+  return pa >= patch;
+}
+
+}  // namespace
+
+void InitTlsSize() {
+  // all current supported platforms have 16 bytes stack alignment
+  const size_t kStackAlign = 16;
+  void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
+  size_t tls_size = 0;
+  size_t tls_align = 0;
+  // On i?86, _dl_get_tls_static_info used to be internal_function, i.e.
+  // __attribute__((regparm(3), stdcall)) before glibc 2.27 and is normal
+  // function in 2.27 and later.
+  if (CHECK_GET_TLS_STATIC_INFO_VERSION && !CmpLibcVersion(2, 27, 0))
+    CallGetTls<GetTlsStaticInfoRegparmCall>(get_tls_static_info_ptr,
+                                            &tls_size, &tls_align);
+  else
+    CallGetTls<GetTlsStaticInfoCall>(get_tls_static_info_ptr,
+                                     &tls_size, &tls_align);
+  if (tls_align < kStackAlign)
+    tls_align = kStackAlign;
+  g_tls_size = RoundUpTo(tls_size, tls_align);
+}
+#else
+void InitTlsSize() { }
+#endif  // SANITIZER_GLIBC && !SANITIZER_GO
+
 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) ||       \
      defined(__aarch64__) || defined(__powerpc64__) || defined(__s390__) || \
      defined(__arm__) || SANITIZER_RISCV64) &&                              \
@@ -262,6 +334,13 @@ uptr ThreadDescriptorSize() {
   return val;
 }
 
+// The offset at which pointer to self is located in the thread descriptor.
+const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
+
+uptr ThreadSelfOffset() {
+  return kThreadSelfOffset;
+}
+
 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
 // head structure. It lies before the static tls blocks.
@@ -280,63 +359,48 @@ static uptr TlsPreTcbSize() {
 }
 #endif
 
-#if !SANITIZER_GO
-namespace {
-struct TlsRange {
-  uptr begin, end, align;
-  size_t tls_modid;
-  bool operator<(const TlsRange &rhs) const { return begin < rhs.begin; }
-};
-}  // namespace
-
-static int CollectStaticTlsRanges(struct dl_phdr_info *info, size_t size,
-                                  void *data) {
-  if (!info->dlpi_tls_data)
-    return 0;
-  const uptr begin = (uptr)info->dlpi_tls_data;
-  for (unsigned i = 0; i != info->dlpi_phnum; ++i)
-    if (info->dlpi_phdr[i].p_type == PT_TLS) {
-      static_cast<InternalMmapVector<TlsRange> *>(data)->push_back(
-          TlsRange{begin, begin + info->dlpi_phdr[i].p_memsz,
-                   info->dlpi_phdr[i].p_align, info->dlpi_tls_modid});
-      break;
-    }
-  return 0;
+uptr ThreadSelf() {
+  uptr descr_addr;
+#if defined(__i386__)
+  asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
+#elif defined(__x86_64__)
+  asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
+#elif defined(__mips__)
+  // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
+  // points to the end of the TCB + 0x7000. The pthread_descr structure is
+  // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
+  // TCB and the size of pthread_descr.
+  const uptr kTlsTcbOffset = 0x7000;
+  uptr thread_pointer;
+  asm volatile(".set push;\
+                .set mips64r2;\
+                rdhwr %0,$29;\
+                .set pop" : "=r" (thread_pointer));
+  descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
+#elif defined(__aarch64__) || defined(__arm__)
+  descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
+                                      ThreadDescriptorSize();
+#elif SANITIZER_RISCV64
+  // https://github.com/riscv/riscv-elf-psabi-doc/issues/53
+  uptr thread_pointer = reinterpret_cast<uptr>(__builtin_thread_pointer());
+  descr_addr = thread_pointer - TlsPreTcbSize();
+#elif defined(__s390__)
+  descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
+#elif defined(__powerpc64__)
+  // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
+  // points to the end of the TCB + 0x7000. The pthread_descr structure is
+  // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
+  // TCB and the size of pthread_descr.
+  const uptr kTlsTcbOffset = 0x7000;
+  uptr thread_pointer;
+  asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
+  descr_addr = thread_pointer - TlsPreTcbSize();
+#else
+#error "unsupported CPU arch"
+#endif
+  return descr_addr;
 }
-
-static void GetStaticTlsRange(uptr *addr, uptr *size, uptr *align) {
-  InternalMmapVector<TlsRange> ranges;
-  dl_iterate_phdr(CollectStaticTlsRanges, &ranges);
-  uptr len = ranges.size();
-  Sort(ranges.begin(), len);
-  // Find the range with tls_modid=1. For glibc, because libc.so uses PT_TLS,
-  // this module is guaranteed to exist and is one of the initially loaded
-  // modules.
-  uptr one = 0;
-  while (one != len && ranges[one].tls_modid != 1) ++one;
-  if (one == len) {
-    // This may happen with musl if no module uses PT_TLS.
-    *addr = 0;
-    *size = 0;
-    *align = 1;
-    return;
-  }
-  // Find the maximum consecutive ranges. We consider two modules consecutive if
-  // the gap is smaller than the alignment. The dynamic loader places static TLS
-  // blocks this way not to waste space.
-  uptr l = one;
-  *align = ranges[l].align;
-  while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l - 1].align)
-    *align = Max(*align, ranges[--l].align);
-  uptr r = one + 1;
-  while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r - 1].align)
-    *align = Max(*align, ranges[r++].align);
-  *addr = ranges[l].begin;
-  *size = ranges[r - 1].end - ranges[l].begin;
-}
-#endif  // !SANITIZER_GO
-#endif  // (x86_64 || i386 || mips || ...) && SANITIZER_LINUX &&
-        // !SANITIZER_ANDROID
+#endif  // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
 
 #if SANITIZER_FREEBSD
 static void **ThreadSelfSegbase() {
@@ -408,54 +472,18 @@ static void GetTls(uptr *addr, uptr *size) {
     *size = 0;
   }
 #elif SANITIZER_LINUX
-  uptr align;
-  GetStaticTlsRange(addr, size, &align);
 #if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
-  if (SANITIZER_GLIBC) {
-#if defined(__s390__)
-    align = Max<uptr>(align, 16);
-#else
-    align = Max<uptr>(align, 64);
-#endif
-  }
-  const uptr tp = RoundUpTo(*addr + *size, align);
-
-  // lsan requires the range to additionally cover the static TLS surplus
-  // (elf/dl-tls.c defines 1664). Otherwise there may be false positives for
-  // allocations only referenced by tls in dynamically loaded modules.
-  if (SANITIZER_GLIBC)
-    *size += 1644;
-
-  // Extend the range to include the thread control block. On glibc, lsan needs
-  // the range to include pthread::{specific_1stblock,specific} so that
-  // allocations only referenced by pthread_setspecific can be scanned. This may
-  // underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine
-  // because the number of bytes after pthread::specific is larger.
-  *addr = tp - RoundUpTo(*size, align);
-  *size = tp - *addr + ThreadDescriptorSize();
-#else
-  if (SANITIZER_GLIBC)
-    *size += 1664;
-#if defined(__powerpc64__)
-  // TODO Figure out why *addr may be zero and use TlsPreTcbSize.
-  void *ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
-  uptr tls_size, tls_align;
-  ((void (*)(size_t *, size_t *))ptr)(&tls_size, &tls_align);
-  asm("addi %0,13,-0x7000" : "=r"(*addr));
-  *addr -= TlsPreTcbSize();
-  *size = RoundUpTo(tls_size + TlsPreTcbSize(), 16);
-#elif defined(__mips__) || SANITIZER_RISCV64
-  const uptr pre_tcb_size = TlsPreTcbSize();
-  *addr -= pre_tcb_size;
-  *size += pre_tcb_size;
+  *addr = ThreadSelf();
+  *size = GetTlsSize();
+  *addr -= *size;
+  *addr += ThreadDescriptorSize();
+#elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__) || \
+    defined(__arm__) || SANITIZER_RISCV64
+  *addr = ThreadSelf();
+  *size = GetTlsSize();
 #else
-  // arm and aarch64 reserve two words at TP, so this underestimates the range.
-  // However, this is sufficient for the purpose of finding the pointers to
-  // thread-specific data keys.
-  const uptr tcb_size = ThreadDescriptorSize();
-  *addr -= tcb_size;
-  *size += tcb_size;
-#endif
+  *addr = 0;
+  *size = 0;
 #endif
 #elif SANITIZER_FREEBSD
   void** segbase = ThreadSelfSegbase();
@@ -496,11 +524,17 @@ static void GetTls(uptr *addr, uptr *size) {
 
 #if !SANITIZER_GO
 uptr GetTlsSize() {
-#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
+#if SANITIZER_FREEBSD || SANITIZER_ANDROID || SANITIZER_NETBSD || \
     SANITIZER_SOLARIS
   uptr addr, size;
   GetTls(&addr, &size);
   return size;
+#elif SANITIZER_GLIBC
+#if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
+  return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
+#else
+  return g_tls_size;
+#endif
 #else
   return 0;
 #endif
@@ -523,9 +557,10 @@ void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
   if (!main) {
     // If stack and tls intersect, make them non-intersecting.
     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
-      if (*stk_addr + *stk_size < *tls_addr + *tls_size)
-        *tls_size = *stk_addr + *stk_size - *tls_addr;
-      *stk_size = *tls_addr - *stk_addr;
+      CHECK_GT(*tls_addr + *tls_size, *stk_addr);
+      CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
+      *stk_size -= *tls_size;
+      *tls_addr = *stk_addr + *stk_size;
     }
   }
 #endif

compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp

@@ -548,6 +548,9 @@ uptr GetTlsSize() {
   return 0;
 }
 
+void InitTlsSize() {
+}
+
 uptr TlsBaseAddr() {
   uptr segbase = 0;
 #if defined(__x86_64__)