Implemented GetSample like POSIX backtrace()

test/cctest/test-sampler-api.cc

Index: test/cctest/test-sampler-api.cc
diff --git a/test/cctest/test-sampler-api.cc b/test/cctest/test-sampler-api.cc
new file mode 100644
index 0000000000000000000000000000000000000000..070315578c716ca86cdae29051c4bc2504d036f5
--- /dev/null
+++ b/test/cctest/test-sampler-api.cc
@@ -0,0 +1,335 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Tests the sampling API in include/v8.h
+
+#include <string>
+#include "include/v8.h"
+#include "src/base/platform/platform.h"
+#include "src/sampler.h"
+#include "src/v8.h"
+#include "test/cctest/cctest.h"
+
+using v8::Local;
+
+namespace {
+static const int kMaxSampleDepth = 10;
+
+// The Sample which CollectSample fills up
+void* sample[kMaxSampleDepth];
+int sample_depth;
+
+// The isolate used in the test
+v8::Isolate* isolate;
+
+#if V8_OS_POSIX && !V8_OS_CYGWIN
+v8::RegisterState GetRegisterState(void* context);
+
+// Signaal handler signals on this semaphore once it finishes.
+v8::base::Semaphore* semaphore;
+
+static void HandleSigprof(int signal, siginfo_t* info, void* context) {
+  USE(info);
+  if (signal != SIGPROF) return;
+  fprintf(stderr, "inside the handler\n");
+  sample_depth = isolate->GetSample(GetRegisterState(context),
+                                    sample,
+                                    kMaxSampleDepth);
+  semaphore->Signal();
+}
+
+
+void InstallSignalHandler() {
+  struct sigaction sa;
+  sa.sa_sigaction = &HandleSigprof;
+  sigemptyset(&sa.sa_mask);
+#if V8_OS_QNX
+  sa.sa_flags = SA_SIGINFO;
+#else
+  sa.sa_flags = SA_RESTART | SA_SIGINFO;
+#endif
+  sigaction(SIGPROF, &sa, 0);
+}
+
+
+// The JavaScript calls this function when on full stack depth.
+void CollectSample(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  semaphore = new v8::base::Semaphore(0);
+  InstallSignalHandler();
+  pthread_kill(pthread_self(), SIGPROF);
+  fprintf(stderr, "Sent the signal\n");
+  semaphore->Wait();
+  delete semaphore;
+  semaphore = NULL;
+}
+
+#elif V8_OS_WIN || V8_OS_CYGWIN
+v8::RegisterState GetRegisterState();
+
+// The JavaScript calls this function when on full stack depth.
+void CollectSample(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  sample_depth = isolate->GetSample(GetRegisterState(),
+                                    sample,
+                                    kMaxSampleDepth);
+}
+#endif   // V8_OS_POSIX && !V8_OS_CYGWIN / V8_OS_WIN || V8_OS_CYGWIN
+
+// A JavaScript function which takes stack depth
+// (minimum value 2) as an argument.
+// When at the bottom of the recursion,
+// the JavaScript code calls into C++ test code,
+// waiting for the sampler to take a sample.
+static const char* test_function =
+    "function func(depth) {"
+    "  if (depth == 2) CollectSample();"
+    "  else return func(depth - 1);"
+    "}";
+}  // namespace
+
+
+#define SAMPLER_API_TESTS_BOOTSTRAP()                                       \
+  isolate = CcTest::isolate();                                              \
+  sample_depth = 0;                                                         \
+  v8::HandleScope scope(isolate);                                           \
+  v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate); \
+  global->Set(v8::String::NewFromUtf8(isolate, "CollectSample"),            \
+              v8::FunctionTemplate::New(isolate, CollectSample));           \
+  LocalContext env(isolate, NULL, global)
+
+
+TEST(StackDepthIsConsistent) {
+  SAMPLER_API_TESTS_BOOTSTRAP();
+
+  std::string source(test_function);
+  source.append("func(8);");
+  v8::Script::Compile(v8::String::NewFromUtf8(isolate, source.c_str()))->Run();
+
+  CHECK_EQ(8, sample_depth);
+}
+
+
+// TEST(StackDepthDoesNotExceedMaxValue) {
+//   SAMPLER_API_TESTS_BOOTSTRAP();
+
+//   std::string source(test_function);
+//   source.append("func(300);");
+//   v8::Script::Compile(v8::String::NewFromUtf8(isolate, source.c_str()))->Run();
+
+//   CHECK_EQ(kMaxSampleDepth, sample_depth);
+// }
+
+
+// namespace {
+// std::vector<v8::JitCodeEvent> inner_funcs;
+// std::vector<v8::JitCodeEvent> outer_funcs;
+
+// void TestJitCodeEventHandler(const v8::JitCodeEvent* event) {
+//   if (event->type != v8::JitCodeEvent::CODE_ADDED) return;
+//   std::string name(event->name.str, event->name.len);
+//   if (name.find("test_sampler_api_inner") != std::string::npos)
+//     inner_funcs.push_back(*event);
+//   if (name.find("test_sampler_api_outer") != std::string::npos)
+//     outer_funcs.push_back(*event);
+// }
+
+
+// // Note: The arguments.callee stuff is there so that the
+// //       functions are not optimized away.
+// static const char* test_script =
+//     "function test_sampler_api_inner() {"
+//     "  CollectSample();"
+//     "  return arguments.callee.toString();"
+//     "}"
+//     "function test_sampler_api_outer() {"
+//     "  return test_sampler_api_inner() + arguments.callee.toString();"
+//     "}"
+//     "test_sampler_api_outer();";
+// }  // namespace
+
+
+// // The captured sample should have three pc values.
+// // They should fall in the range where the compiled code
+// // The expected stack is:
+// // bottom of stack [{anon script}, outer, inner] top of stack
+// //                              ^      ^       ^
+// // sample.stack indices         2      1       0
+// TEST(StackFramesConsistent) {
+//   SAMPLER_API_TESTS_BOOTSTRAP();
+
+//   isolate->SetJitCodeEventHandler(v8::kJitCodeEventDefault,
+//                                   TestJitCodeEventHandler);
+//   v8::Script::Compile(v8::String::NewFromUtf8(isolate, test_script))->Run();
+
+//   CHECK_EQ(3, sample_depth);
+
+//   bool stack_top_is_inner = false;
+//   bool below_inner_is_outer = false;
+
+//   for (unsigned i = 0; i < inner_funcs.size(); i++) {
+//     void* start_addr = inner_funcs[i].code_start;
+//     void* end_addr = reinterpret_cast<void*>(
+//         (int64_t)inner_funcs[i].code_start + inner_funcs[i].code_len);
+//     if ((sample[0] >= start_addr) && (sample[0] < end_addr))
+//       stack_top_is_inner = true;
+//   }
+
+//   for (unsigned i = 0; i < outer_funcs.size(); i++) {
+//     void* start_addr = outer_funcs[i].code_start;
+//     void* end_addr = reinterpret_cast<void*>(
+//         (int64_t)outer_funcs[i].code_start + outer_funcs[i].code_len);
+//     if ((sample[1] >= start_addr) &&
+//         (sample[1] < end_addr))
+//       below_inner_is_outer = true;
+//   }
+
+//   CHECK(stack_top_is_inner);
+//   CHECK(below_inner_is_outer);
+// }
+
+
+// Platform specific implementation of GetRegisterState
+namespace {
+#if V8_OS_POSIX && !V8_OS_CYGWIN
+v8::RegisterState GetRegisterState(void* context) {
+  v8::RegisterState state;
+  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+#if !V8_OS_OPENBSD
+  mcontext_t& mcontext = ucontext->uc_mcontext;
+#endif
+#if V8_OS_LINUX
+#if V8_HOST_ARCH_IA32
+  state.pc = reinterpret_cast<void*>(mcontext.gregs[REG_EIP]);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[REG_ESP]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  state.pc = reinterpret_cast<void*>(mcontext.gregs[REG_RIP]);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[REG_RSP]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[REG_RBP]);
+#elif V8_HOST_ARCH_ARM
+#if defined(__GLIBC__) && !defined(__UCLIBC__) && \
+    (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+  // Old GLibc ARM versions used a gregs[] array to access the register
+  // values from mcontext_t.
+  state.pc = reinterpret_cast<void*>(mcontext.gregs[R15]);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[R13]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[R11]);
+#else
+  state.pc = reinterpret_cast<void*>(mcontext.arm_pc);
+  state.sp = reinterpret_cast<void*>(mcontext.arm_sp);
+  state.fp = reinterpret_cast<void*>(mcontext.arm_fp);
+#endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
+        // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+#elif V8_HOST_ARCH_ARM64
+  state.pc = reinterpret_cast<void*>(mcontext.pc);
+  state.sp = reinterpret_cast<void*>(mcontext.sp);
+  // FP is an alias for x29.
+  state.fp = reinterpret_cast<void*>(mcontext.regs[29]);
+#elif V8_HOST_ARCH_MIPS
+  state.pc = reinterpret_cast<void*>(mcontext.pc);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[29]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[30]);
+#elif V8_HOST_ARCH_MIPS64
+  state.pc = reinterpret_cast<void*>(mcontext.pc);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[29]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[30]);
+#endif  // V8_HOST_ARCH_*
+#elif V8_OS_MACOSX
+#if V8_HOST_ARCH_X64
+#if __DARWIN_UNIX03
+  state.pc = reinterpret_cast<void*>(mcontext->__ss.__rip);
+  state.sp = reinterpret_cast<void*>(mcontext->__ss.__rsp);
+  state.fp = reinterpret_cast<void*>(mcontext->__ss.__rbp);
+#else  // !__DARWIN_UNIX03
+  state.pc = reinterpret_cast<void*>(mcontext->ss.rip);
+  state.sp = reinterpret_cast<void*>(mcontext->ss.rsp);
+  state.fp = reinterpret_cast<void*>(mcontext->ss.rbp);
+#endif  // __DARWIN_UNIX03
+#elif V8_HOST_ARCH_IA32
+#if __DARWIN_UNIX03
+  state.pc = reinterpret_cast<void*>(mcontext->__ss.__eip);
+  state.sp = reinterpret_cast<void*>(mcontext->__ss.__esp);
+  state.fp = reinterpret_cast<void*>(mcontext->__ss.__ebp);
+#else  // !__DARWIN_UNIX03
+  state.pc = reinterpret_cast<void*>(mcontext->ss.eip);
+  state.sp = reinterpret_cast<void*>(mcontext->ss.esp);
+  state.fp = reinterpret_cast<void*>(mcontext->ss.ebp);
+#endif  // __DARWIN_UNIX03
+#endif  // V8_HOST_ARCH_IA32
+#elif V8_OS_FREEBSD
+#if V8_HOST_ARCH_IA32
+  state.pc = reinterpret_cast<void*>(mcontext.mc_eip);
+  state.sp = reinterpret_cast<void*>(mcontext.mc_esp);
+  state.fp = reinterpret_cast<void*>(mcontext.mc_ebp);
+#elif V8_HOST_ARCH_X64
+  state.pc = reinterpret_cast<void*>(mcontext.mc_rip);
+  state.sp = reinterpret_cast<void*>(mcontext.mc_rsp);
+  state.fp = reinterpret_cast<void*>(mcontext.mc_rbp);
+#elif V8_HOST_ARCH_ARM
+  state.pc = reinterpret_cast<void*>(mcontext.mc_r15);
+  state.sp = reinterpret_cast<void*>(mcontext.mc_r13);
+  state.fp = reinterpret_cast<void*>(mcontext.mc_r11);
+#endif  // V8_HOST_ARCH_*
+#elif V8_OS_NETBSD
+#if V8_HOST_ARCH_IA32
+  state.pc = reinterpret_cast<void*>(mcontext.__gregs[_REG_EIP]);
+  state.sp = reinterpret_cast<void*>(mcontext.__gregs[_REG_ESP]);
+  state.fp = reinterpret_cast<void*>(mcontext.__gregs[_REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  state.pc = reinterpret_cast<void*>(mcontext.__gregs[_REG_RIP]);
+  state.sp = reinterpret_cast<void*>(mcontext.__gregs[_REG_RSP]);
+  state.fp = reinterpret_cast<void*>(mcontext.__gregs[_REG_RBP]);
+#endif  // V8_HOST_ARCH_*
+#elif V8_OS_OPENBSD
+#if V8_HOST_ARCH_IA32
+  state.pc = reinterpret_cast<void*>(ucontext->sc_eip);
+  state.sp = reinterpret_cast<void*>(ucontext->sc_esp);
+  state.fp = reinterpret_cast<void*>(ucontext->sc_ebp);
+#elif V8_HOST_ARCH_X64
+  state.pc = reinterpret_cast<void*>(ucontext->sc_rip);
+  state.sp = reinterpret_cast<void*>(ucontext->sc_rsp);
+  state.fp = reinterpret_cast<void*>(ucontext->sc_rbp);
+#endif  // V8_HOST_ARCH_*
+#elif V8_OS_SOLARIS
+  state.pc = reinterpret_cast<void*>(mcontext.gregs[REG_PC]);
+  state.sp = reinterpret_cast<void*>(mcontext.gregs[REG_SP]);
+  state.fp = reinterpret_cast<void*>(mcontext.gregs[REG_FP]);
+#elif V8_OS_QNX
+#if V8_HOST_ARCH_IA32
+  state.pc = reinterpret_cast<void*>(mcontext.cpu.eip);
+  state.sp = reinterpret_cast<void*>(mcontext.cpu.esp);
+  state.fp = reinterpret_cast<void*>(mcontext.cpu.ebp);
+#elif V8_HOST_ARCH_ARM
+  state.pc = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_PC]);
+  state.sp = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_SP]);
+  state.fp = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_FP]);
+#endif  // V8_HOST_ARCH_*
+#endif  // V8_OS_QNX
+  return state;
+}
+
+#elif V8_OS_WIN || V8_OS_CYGWIN
+v8::RegisterState GetRegisterState() {
+  CONTEXT context;
+  v8::RegisterState state;
+  memset(&context, 0, sizeof(context));
+  context.ContextFlags = CONTEXT_FULL;
+  GetThreadContext(OpenThread(THREAD_GET_CONTEXT |
+                              THREAD_SUSPEND_RESUME |
+                              THREAD_QUERY_INFORMATION,
+                              false,
+                              GetCurrentThreadId()),
+                   &context);
+#if V8_HOST_ARCH_X64
+  state.pc = reinterpret_cast<void*>(context.Rip);
+  state.sp = reinterpret_cast<void*>(context.Rsp);
+  state.fp = reinterpret_cast<void*>(context.Rbp);
+#else
+  state.pc = reinterpret_cast<void*>(context.Eip);
+  state.sp = reinterpret_cast<void*>(context.Esp);
+  state.fp = reinterpret_cast<void*>(context.Ebp);
+#endif
+  return state;
+}
+#endif  // V8_OS_POSIX && !V8_OS_CYGWIN / V8_OS_WIN || V8_OS_CYGWIN
+}  // namespace