Introduce stats and stats_client libraries.

This is part of a new statistics gathering feature for the sanitizers.
See clang/docs/SanitizerStats.rst for further info and docs.

Differential Revision: http://reviews.llvm.org/D16176

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@257972 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 289 insertions, 0 deletions

diff --git a/lib/stats/CMakeLists.txt b/lib/stats/CMakeLists.txt
new file mode 100644
index 000000000..086ee090a
--- /dev/null
+++ b/lib/stats/CMakeLists.txt
@@ -0,0 +1,27 @@
+include_directories(..)
+
+add_custom_target(stats)
+
+if(APPLE)
+  set(STATS_LIB_FLAVOR SHARED)
+else()
+  set(STATS_LIB_FLAVOR STATIC)
+endif()
+
+add_compiler_rt_runtime(clang_rt.stats
+  ${STATS_LIB_FLAVOR}
+  ARCHS ${SANITIZER_COMMON_SUPPORTED_ARCH}
+  OS ${SANITIZER_COMMON_SUPPORTED_OS}
+  SOURCES stats.cc
+  OBJECT_LIBS RTSanitizerCommon
+              RTSanitizerCommonLibc
+  CFLAGS ${SANITIZER_COMMON_CFLAGS}
+  PARENT_TARGET stats)
+
+add_compiler_rt_runtime(clang_rt.stats_client
+  STATIC
+  ARCHS ${SANITIZER_COMMON_SUPPORTED_ARCH}
+  OS ${SANITIZER_COMMON_SUPPORTED_OS}
+  SOURCES stats_client.cc
+  CFLAGS ${SANITIZER_COMMON_CFLAGS}
+  PARENT_TARGET stats)
diff --git a/lib/stats/stats.cc b/lib/stats/stats.cc
new file mode 100644
index 000000000..6b937f1c8
--- /dev/null
+++ b/lib/stats/stats.cc
@@ -0,0 +1,136 @@
+//===-- stats.cc ----------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Sanitizer statistics gathering. Manages statistics for a process and is
+// responsible for writing the report file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#if SANITIZER_POSIX
+#include "sanitizer_common/sanitizer_posix.h"
+#endif
+#include "sanitizer_common/sanitizer_symbolizer.h"
+#include "stats/stats.h"
+#if SANITIZER_POSIX
+#include <signal.h>
+#endif
+
+using namespace __sanitizer;
+
+namespace {
+
+InternalMmapVectorNoCtor<StatModule **> modules;
+StaticSpinMutex modules_mutex;
+
+fd_t stats_fd;
+
+void WriteLE(fd_t fd, uptr val) {
+  char chars[sizeof(uptr)];
+  for (unsigned i = 0; i != sizeof(uptr); ++i) {
+    chars[i] = val >> (i * 8);
+  }
+  WriteToFile(fd, chars, sizeof(uptr));
+}
+
+void OpenStatsFile(const char *path_env) {
+  InternalScopedBuffer<char> path(kMaxPathLength);
+  SubstituteForFlagValue(path_env, path.data(), kMaxPathLength);
+
+  error_t err;
+  stats_fd = OpenFile(path.data(), WrOnly, &err);
+  if (stats_fd == kInvalidFd) {
+    Report("stats: failed to open %s for writing (reason: %d)\n", path.data(),
+           err);
+    return;
+  }
+  char sizeof_uptr = sizeof(uptr);
+  WriteToFile(stats_fd, &sizeof_uptr, 1);
+}
+
+void WriteModuleReport(StatModule **smodp) {
+  CHECK(smodp);
+  const char *path_env = GetEnv("SANITIZER_STATS_PATH");
+  if (!path_env || stats_fd == kInvalidFd)
+    return;
+  if (!stats_fd)
+    OpenStatsFile(path_env);
+  LoadedModule *mod = Symbolizer::GetOrInit()->FindModuleForAddress(
+      reinterpret_cast<uptr>(smodp));
+  WriteToFile(stats_fd, mod->full_name(),
+              internal_strlen(mod->full_name()) + 1);
+  for (StatModule *smod = *smodp; smod; smod = smod->next) {
+    for (u32 i = 0; i != smod->size; ++i) {
+      StatInfo *s = &smod->infos[i];
+      if (!s->addr)
+        continue;
+      WriteLE(stats_fd, s->addr - mod->base_address());
+      WriteLE(stats_fd, s->data);
+    }
+  }
+  WriteLE(stats_fd, 0);
+  WriteLE(stats_fd, 0);
+}
+
+} // namespace
+
+extern "C"
+SANITIZER_INTERFACE_ATTRIBUTE
+unsigned __sanitizer_stats_register(StatModule **mod) {
+  SpinMutexLock l(&modules_mutex);
+  modules.push_back(mod);
+  return modules.size() - 1;
+}
+
+extern "C"
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_stats_unregister(unsigned index) {
+  SpinMutexLock l(&modules_mutex);
+  WriteModuleReport(modules[index]);
+  modules[index] = 0;
+}
+
+namespace {
+
+void WriteFullReport() {
+  SpinMutexLock l(&modules_mutex);
+  for (StatModule **mod : modules) {
+    if (!mod)
+      continue;
+    WriteModuleReport(mod);
+  }
+  if (stats_fd != 0 && stats_fd != kInvalidFd) {
+    CloseFile(stats_fd);
+    stats_fd = kInvalidFd;
+  }
+}
+
+#if SANITIZER_POSIX
+void USR2Handler(int sig) {
+  WriteFullReport();
+}
+#endif
+
+struct WriteReportOnExitOrSignal {
+  WriteReportOnExitOrSignal() {
+#if SANITIZER_POSIX
+    struct sigaction sigact;
+    internal_memset(&sigact, 0, sizeof(sigact));
+    sigact.sa_handler = USR2Handler;
+    internal_sigaction(SIGUSR2, &sigact, nullptr);
+#endif
+  }
+
+  ~WriteReportOnExitOrSignal() {
+    WriteFullReport();
+  }
+} wr;
+
+} // namespace
diff --git a/lib/stats/stats.h b/lib/stats/stats.h
new file mode 100644
index 000000000..619470677
--- /dev/null
+++ b/lib/stats/stats.h
@@ -0,0 +1,43 @@
+//===-- stats.h -------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Data definitions for sanitizer statistics gathering.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_STATS_STATS_H
+#define SANITIZER_STATS_STATS_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+
+namespace __sanitizer {
+
+// Number of bits in data that are used for the sanitizer kind. Needs to match
+// llvm::kSanitizerStatKindBits in
+// llvm/include/llvm/Transforms/Utils/SanitizerStats.h
+enum { kKindBits = 3 };
+
+struct StatInfo {
+  uptr addr;
+  uptr data;
+};
+
+struct StatModule {
+  StatModule *next;
+  u32 size;
+  StatInfo infos[1];
+};
+
+inline uptr CountFromData(uptr data) {
+  return data & ((1ull << (sizeof(uptr) * 8 - kKindBits)) - 1);
+}
+
+}
+
+#endif
diff --git a/lib/stats/stats_client.cc b/lib/stats/stats_client.cc
new file mode 100644
index 000000000..fa4b2d909
--- /dev/null
+++ b/lib/stats/stats_client.cc
@@ -0,0 +1,83 @@
+//===-- stats_client.cc ---------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Sanitizer statistics gathering. Manages statistics for a module (executable
+// or DSO) and registers statistics with the process.
+//
+// This is linked into each individual modle and cannot directly use functions
+// declared in sanitizer_common.
+//
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+#include <stdint.h>
+#include <stdio.h>
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "stats/stats.h"
+
+using namespace __sanitizer;
+
+namespace {
+
+void *LookupSymbolFromMain(const char *name) {
+#ifdef _WIN32
+  return reinterpret_cast<void *>(GetProcAddress(GetModuleHandle(0), name));
+#else
+  return dlsym(RTLD_DEFAULT, name);
+#endif
+}
+
+StatModule *list;
+
+struct RegisterSanStats {
+  unsigned module_id;
+
+  RegisterSanStats() {
+    typedef unsigned (*reg_func_t)(StatModule **);
+    reg_func_t reg_func = reinterpret_cast<reg_func_t>(
+        LookupSymbolFromMain("__sanitizer_stats_register"));
+    if (reg_func)
+      module_id = reg_func(&list);
+  }
+
+  ~RegisterSanStats() {
+    typedef void (*unreg_func_t)(unsigned);
+    unreg_func_t unreg_func = reinterpret_cast<unreg_func_t>(
+        LookupSymbolFromMain("__sanitizer_stats_unregister"));
+    if (unreg_func)
+      unreg_func(module_id);
+  }
+} reg;
+
+}
+
+extern "C" void __sanitizer_stat_init(StatModule *mod) {
+  mod->next = list;
+  list = mod;
+}
+
+extern "C" void __sanitizer_stat_report(StatInfo *s) {
+  s->addr = GET_CALLER_PC();
+#if defined(_WIN64) && !defined(__clang__)
+  uptr old_data = InterlockedIncrement64(reinterpret_cast<LONG64 *>(&s->data));
+#elif defined(_WIN32) && !defined(__clang__)
+  uptr old_data = InterlockedIncrement(&s->data);
+#else
+  uptr old_data = __sync_fetch_and_add(&s->data, 1);
+#endif
+
+  // Overflow check.
+  if (CountFromData(old_data + 1) == 0)
+    Trap();
+}