base: make CHECK macros trap at distinct addresses in official builds

base/logging_unittest.cc

Index: base/logging_unittest.cc
diff --git a/base/logging_unittest.cc b/base/logging_unittest.cc
index 9fe718c8799a4e74f170091ca148033373c79161..e6450b09ffedac97d01d9cb24441e980eb676b38 100644
--- a/base/logging_unittest.cc
+++ b/base/logging_unittest.cc
@@ -9,6 +9,16 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_POSIX)
+#include <signal.h>
+#include <unistd.h>
+#include "base/posix/eintr_wrapper.h"
+#endif  // OS_POSIX
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+#include <ucontext.h>
+#endif
+
 #if defined(OS_WIN)
 #include <excpt.h>
 #include <windows.h>
@@ -246,7 +256,102 @@ TEST_F(LoggingTest, CheckCausesDistinctBreakpoints) {
   EXPECT_NE(addr1, addr3);
   EXPECT_NE(addr2, addr3);
 }
-#endif  // OFFICIAL_BUILD && OS_WIN
+
+#elif defined(OS_POSIX) && \
+    (defined(ARCH_CPU_X86_FAMILY) || defined(ARCH_CPU_ARM_FAMILY))
+
+int g_child_crash_pipe;
+
+void CheckCrashTestSighandler(int, siginfo_t* info, void* context_ptr) {
+  // Conversely to what clearly stated in "man 2 sigaction", some Linux kernels
+  // do NOT populate the |info->si_addr| in the case of a SIGTRAP. Hence we
+  // need the arch-specific boilerplate below, which is inspired by breakpad.
+  // At the same time, on OSX, ucontext.h is deprecated but si_addr works fine.
+  uintptr_t crash_addr = 0;
+#if defined(OS_MACOSX)
+  crash_addr = reinterpret_cast<uintptr_t>(info->si_addr);
+#else  // OS_POSIX && !OS_MACOSX
+  struct ucontext* context = reinterpret_cast<struct ucontext*>(context_ptr);
+#if defined(ARCH_CPU_X86)
+  crash_addr = static_cast<uintptr_t>(context->uc_mcontext.gregs[REG_EIP]);
+#elif defined(ARCH_CPU_X86_64)
+  crash_addr = static_cast<uintptr_t>(context->uc_mcontext.gregs[REG_RIP]);
+#elif defined(ARCH_CPU_ARMEL)
+  crash_addr = static_cast<uintptr_t>(context->uc_mcontext.arm_pc);
+#elif defined(ARCH_CPU_ARM64)
+  crash_addr = static_cast<uintptr_t>(context->uc_mcontext.pc);
+#endif  // ARCH_*
+#endif  // OS_POSIX && !OS_MACOSX
+  HANDLE_EINTR(write(g_child_crash_pipe, &crash_addr, sizeof(uintptr_t)));
+  _exit(0);
+}
+
+// CHECK causes a direct crash (without jumping to another function) only in
+// official builds. Unfortunately, continuous test coverage on official builds
+// is lower. DO_CHECK here falls back on a home-brewed implementation in
+// non-official builds, to catch regressions earlier in the CQ.
+#if defined(OFFICIAL_BUILD)
+#define DO_CHECK CHECK
+#else
+#define DO_CHECK(cond) \
+  if (!(cond))         \
+  IMMEDIATE_CRASH()
+#endif
+
+void CrashChildMain(int death_location) {
+  struct sigaction act = {};
+  act.sa_sigaction = CheckCrashTestSighandler;
+  act.sa_flags = SA_SIGINFO;
+  ASSERT_EQ(0, sigaction(SIGTRAP, &act, NULL));
+  ASSERT_EQ(0, sigaction(SIGBUS, &act, NULL));
+  ASSERT_EQ(0, sigaction(SIGILL, &act, NULL));
+  DO_CHECK(death_location != 1);
+  DO_CHECK(death_location != 2);
+  printf("\n");
+  DO_CHECK(death_location != 3);
+
+  // Should never reach this point.
+  const uintptr_t failed = 0;
+  HANDLE_EINTR(write(g_child_crash_pipe, &failed, sizeof(uintptr_t)));
+};
+
+void SpawnChildAndCrash(int death_location, uintptr_t* child_crash_addr) {
+  int pipefd[2];
+  ASSERT_EQ(0, pipe(pipefd));
+
+  int pid = fork();
+  ASSERT_GE(pid, 0);
+
+  if (pid == 0) {      // child process.
+    close(pipefd[0]);  // Close reader (parent) end.
+    g_child_crash_pipe = pipefd[1];
+    CrashChildMain(death_location);
+    FAIL() << "The child process was supposed to crash. It didn't.";
+  }
+
+  close(pipefd[1]);  // Close writer (child) end.
+  DCHECK(child_crash_addr);
+  int res = HANDLE_EINTR(read(pipefd[0], child_crash_addr, sizeof(uintptr_t)));
+  ASSERT_EQ(static_cast<int>(sizeof(uintptr_t)), res);
+}
+
+TEST_F(LoggingTest, CheckCausesDistinctBreakpoints) {
+  uintptr_t child_crash_addr_1 = 0;
+  uintptr_t child_crash_addr_2 = 0;
+  uintptr_t child_crash_addr_3 = 0;
+
+  SpawnChildAndCrash(1, &child_crash_addr_1);
+  SpawnChildAndCrash(2, &child_crash_addr_2);
+  SpawnChildAndCrash(3, &child_crash_addr_3);
+
+  ASSERT_NE(0u, child_crash_addr_1);
+  ASSERT_NE(0u, child_crash_addr_2);
+  ASSERT_NE(0u, child_crash_addr_3);
+  ASSERT_NE(child_crash_addr_1, child_crash_addr_2);
+  ASSERT_NE(child_crash_addr_1, child_crash_addr_3);
+  ASSERT_NE(child_crash_addr_2, child_crash_addr_3);
+}
+#endif  // OS_POSIX
 
 TEST_F(LoggingTest, DebugLoggingReleaseBehavior) {
 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)