sanitizers: Make sure Visual Studio gets error reports

Visual Studio appears to close stderr before launching a non-console
win32 program.  This means we don't see any sanitizer reports.  If
stderr printing fails, call OutputDebugStringA to get the reports into
the Visual Studio debugger console.

llvm-svn: 190030

compiler-rt/lib/sanitizer_common/sanitizer_common.cc

@@ -26,16 +26,19 @@ uptr GetPageSizeCached() {
   return PageSize;
 }
 
-static bool log_to_file = false;  // Set to true by __sanitizer_set_report_path
 
 // By default, dump to stderr. If |log_to_file| is true and |report_fd_pid|
 // isn't equal to the current PID, try to obtain file descriptor by opening
 // file "report_path_prefix.<PID>".
 fd_t report_fd = kStderrFd;
-static char report_path_prefix[4096];  // Set via __sanitizer_set_report_path.
+
+// Set via __sanitizer_set_report_path.
+bool log_to_file = false;
+char report_path_prefix[sizeof(report_path_prefix)];
+
 // PID of process that opened |report_fd|. If a fork() occurs, the PID of the
 // child thread will be different from |report_fd_pid|.
-static uptr report_fd_pid = 0;
+uptr report_fd_pid = 0;
 
 static DieCallbackType DieCallback;
 void SetDieCallback(DieCallbackType callback) {
@@ -68,36 +71,6 @@ void NORETURN CheckFailed(const char *file, int line, const char *cond,
   Die();
 }
 
-void MaybeOpenReportFile() {
-  if (!log_to_file || (report_fd_pid == internal_getpid())) return;
-  InternalScopedBuffer<char> report_path_full(4096);
-  internal_snprintf(report_path_full.data(), report_path_full.size(),
-                    "%s.%d", report_path_prefix, internal_getpid());
-  uptr openrv = OpenFile(report_path_full.data(), true);
-  if (internal_iserror(openrv)) {
-    report_fd = kStderrFd;
-    log_to_file = false;
-    Report("ERROR: Can't open file: %s\n", report_path_full.data());
-    Die();
-  }
-  if (report_fd != kInvalidFd) {
-    // We're in the child. Close the parent's log.
-    internal_close(report_fd);
-  }
-  report_fd = openrv;
-  report_fd_pid = internal_getpid();
-}
-
-void RawWrite(const char *buffer) {
-  static const char *kRawWriteError = "RawWrite can't output requested buffer!";
-  uptr length = (uptr)internal_strlen(buffer);
-  MaybeOpenReportFile();
-  if (length != internal_write(report_fd, buffer, length)) {
-    internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
-    Die();
-  }
-}
-
 uptr ReadFileToBuffer(const char *file_name, char **buff,
                       uptr *buff_size, uptr max_len) {
   uptr PageSize = GetPageSizeCached();

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -116,6 +116,9 @@ void SetPrintfAndReportCallback(void (*callback)(const char *));
 extern StaticSpinMutex CommonSanitizerReportMutex;
 void MaybeOpenReportFile();
 extern fd_t report_fd;
+extern bool log_to_file;
+extern char report_path_prefix[4096];
+extern uptr report_fd_pid;
 
 uptr OpenFile(const char *filename, bool write);
 // Opens the file 'file_name" and reads up to 'max_len' bytes.

compiler-rt/lib/sanitizer_common/sanitizer_posix.cc

@@ -197,6 +197,37 @@ char *FindPathToBinary(const char *name) {
   return 0;
 }
 
+void MaybeOpenReportFile() {
+  if (!log_to_file || (report_fd_pid == internal_getpid())) return;
+  InternalScopedBuffer<char> report_path_full(4096);
+  internal_snprintf(report_path_full.data(), report_path_full.size(),
+                    "%s.%d", report_path_prefix, internal_getpid());
+  uptr openrv = OpenFile(report_path_full.data(), true);
+  if (internal_iserror(openrv)) {
+    report_fd = kStderrFd;
+    log_to_file = false;
+    Report("ERROR: Can't open file: %s\n", report_path_full.data());
+    Die();
+  }
+  if (report_fd != kInvalidFd) {
+    // We're in the child. Close the parent's log.
+    internal_close(report_fd);
+  }
+  report_fd = openrv;
+  report_fd_pid = internal_getpid();
+}
+
+void RawWrite(const char *buffer) {
+  static const char *kRawWriteError =
+      "RawWrite can't output requested buffer!\n";
+  uptr length = (uptr)internal_strlen(buffer);
+  MaybeOpenReportFile();
+  if (length != internal_write(report_fd, buffer, length)) {
+    internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
+    Die();
+  }
+}
+
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_LINUX || SANITIZER_MAC

compiler-rt/lib/sanitizer_common/sanitizer_win.cc

@@ -398,6 +398,24 @@ void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp,
     stack->trace[i] = (uptr)tmp[i + offset];
 }
 
+void MaybeOpenReportFile() {
+  // Windows doesn't have native fork, and we don't support Cygwin or other
+  // environments that try to fake it, so the initial report_fd will always be
+  // correct.
+}
+
+void RawWrite(const char *buffer) {
+  static const char *kRawWriteError =
+      "RawWrite can't output requested buffer!\n";
+  uptr length = (uptr)internal_strlen(buffer);
+  if (length != internal_write(report_fd, buffer, length)) {
+    // stderr may be closed, but we may be able to print to the debugger
+    // instead.  This is the case when launching a program from Visual Studio,
+    // and the following routine should write to its console.
+    OutputDebugStringA(buffer);
+  }
+}
+
 }  // namespace __sanitizer
 
 #endif  // _WIN32