[asan] add asan option log_path=PATH to let users redirect asan reports to a file PATH.PID instead of stderr

llvm-svn: 163872

2 files changed, 34 insertions, 3 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.cc b/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
index 22c7093db5f..614b7b9d465 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.cc
@@ -16,6 +16,9 @@
 
 namespace __sanitizer {
 
+static fd_t report_fd = 2;  // By default, dump to stderr.
+static char report_path[4096];  // Set via __sanitizer_set_report_path.
+
 static void (*DieCallback)(void);
 void SetDieCallback(void (*callback)(void)) {
   DieCallback = callback;
@@ -46,8 +49,17 @@ void NORETURN CheckFailed(const char *file, int line, const char *cond,
 void RawWrite(const char *buffer) {
   static const char *kRawWriteError = "RawWrite can't output requested buffer!";
   uptr length = (uptr)internal_strlen(buffer);
-  if (length != internal_write(2, buffer, length)) {
-    internal_write(2, kRawWriteError, internal_strlen(kRawWriteError));
+  if (report_fd == kInvalidFd) {
+    fd_t fd = internal_open(report_path, true);
+    if (fd == kInvalidFd) {
+      report_fd = 2;
+      Report("ERROR: Can't open file: %s\n", report_path);
+      Die();
+    }
+    report_fd = fd;
+  }
+  if (length != internal_write(report_fd, buffer, length)) {
+    internal_write(report_fd, kRawWriteError, internal_strlen(kRawWriteError));
     Die();
   }
 }
@@ -125,3 +137,17 @@ void SortArray(uptr *array, uptr size) {
 }
 
 }  // namespace __sanitizer
+
+void __sanitizer_set_report_path(const char *path) {
+  if (!path) return;
+  uptr len = internal_strlen(path);
+  if (len > sizeof(__sanitizer::report_path) - 100) {
+    Report("ERROR: Path is too long: %c%c%c%c%c%c%c%c...\n",
+           path[0], path[1], path[2], path[3],
+           path[4], path[5], path[6], path[7]);
+    Die();
+  }
+  internal_snprintf(__sanitizer::report_path,
+                    sizeof(__sanitizer::report_path), "%s.%d", path, GetPid());
+  __sanitizer::report_fd = kInvalidFd;
+}
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_printf.cc b/compiler-rt/lib/sanitizer_common/sanitizer_printf.cc
index 22f10fb1a00..6aeedabdf3f 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_printf.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_printf.cc
@@ -86,7 +86,7 @@ static int AppendPointer(char **buff, const char *buff_end, u64 ptr_value) {
 int VSNPrintf(char *buff, int buff_length,
               const char *format, va_list args) {
   static const char *kPrintfFormatsHelp = "Supported Printf formats: "
-                                          "%%[z]{d,u,x}; %%p; %%s\n";
+                                          "%%[z]{d,u,x}; %%p; %%s; %%c\n";
   RAW_CHECK(format);
   RAW_CHECK(buff_length > 0);
   const char *buff_end = &buff[buff_length - 1];
@@ -127,6 +127,11 @@ int VSNPrintf(char *buff, int buff_length,
         result += AppendString(&buff, buff_end, va_arg(args, char*));
         break;
       }
+      case 'c': {
+        RAW_CHECK_MSG(!have_z, kPrintfFormatsHelp);
+        result += AppendChar(&buff, buff_end, va_arg(args, uptr));
+        break;
+      }
       case '%' : {
         RAW_CHECK_MSG(!have_z, kPrintfFormatsHelp);
         result += AppendChar(&buff, buff_end, '%');