Index: lib/asan/asan_report.cc
===================================================================
--- lib/asan/asan_report.cc
+++ lib/asan/asan_report.cc
@@ -23,6 +23,11 @@
 #include "sanitizer_common/sanitizer_stackdepot.h"
 #include "sanitizer_common/sanitizer_symbolizer.h"
 
+#if SANITIZER_MAC
+# include <asl.h>
+# include <os/trace.h>
+#endif
+
 namespace __asan {
 
 // -------------------- User-specified callbacks ----------------- {{{1
@@ -45,16 +50,21 @@
 static ReportData report_data = {};
 
 void AppendToErrorMessageBuffer(const char *buffer) {
-  if (error_message_buffer) {
-    uptr length = internal_strlen(buffer);
-    CHECK_GE(error_message_buffer_size, error_message_buffer_pos);
-    uptr remaining = error_message_buffer_size - error_message_buffer_pos;
-    internal_strncpy(error_message_buffer + error_message_buffer_pos,
-                     buffer, remaining);
-    error_message_buffer[error_message_buffer_size - 1] = '\0';
-    // FIXME: reallocate the buffer instead of truncating the message.
-    error_message_buffer_pos += Min(remaining, length);
+  if (!error_message_buffer) {
+    error_message_buffer_size = 1 << 16;
+    error_message_buffer =
+        (char*)MmapOrDie(error_message_buffer_size, __func__);
+    error_message_buffer_pos = 0;
   }
+
+  uptr length = internal_strlen(buffer);
+  CHECK_GE(error_message_buffer_size, error_message_buffer_pos);
+  uptr remaining = error_message_buffer_size - error_message_buffer_pos;
+  internal_strncpy(error_message_buffer + error_message_buffer_pos,
+                   buffer, remaining);
+  error_message_buffer[error_message_buffer_size - 1] = '\0';
+  // FIXME: reallocate the buffer instead of truncating the message.
+  error_message_buffer_pos += Min(remaining, length);
 }
 
 // ---------------------- Decorator ------------------------------ {{{1
@@ -617,6 +627,36 @@
 
 // -------------------- Different kinds of reports ----------------- {{{1
 
+// Removes the ANSI escape sequences from the input string (in-place).
+void RemoveANSIEscapeSequencesFromString(char *str) {
+  if (!str)
+    return;
+
+  // We are going to remove the escape sequences in place.
+  char *s = str;
+  char *z = str;
+  while (*s != '\0') {
+    // Skip ANSI escape sequences.
+    if (*s == '\033' && *(s + 1) == '[') {
+      while (*s != 'm' && *s != '\0') {
+        s++;
+      }
+      if (*s == '\0') {
+        break;
+      }
+    // Copy over the buffer content.
+    } else if (s != z) {
+      CHECK_GT(s, z);
+      *z = *s;
+      z++;
+    }
+    s++;
+  }
+
+  // Null terminate the string.
+  *z = '\0';
+}
+
 // Use ScopedInErrorReport to run common actions just before and
 // immediately after printing error report.
 class ScopedInErrorReport {
@@ -663,6 +703,20 @@
     // Print memory stats.
     if (flags()->print_stats)
       __asan_print_accumulated_stats();
+
+#if SANITIZER_MAC
+    RemoveANSIEscapeSequencesFromString(error_message_buffer);
+
+    // Log the full message to syslog.
+    asl_log(nullptr, nullptr, ASL_LEVEL_ERR, "%s", error_message_buffer);
+
+    // Log with os_trace. This will make it into the crash log.
+    if (&_os_trace_with_buffer != nullptr) {
+      os_trace("AddressSanitizer reported a failure. "
+               "Consult syslog for more information.");
+    }
+#endif
+
     if (error_report_callback) {
       error_report_callback(error_message_buffer);
     }
@@ -1061,12 +1115,6 @@
 
 void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
   error_report_callback = callback;
-  if (callback) {
-    error_message_buffer_size = 1 << 16;
-    error_message_buffer =
-        (char*)MmapOrDie(error_message_buffer_size, __func__);
-    error_message_buffer_pos = 0;
-  }
 }
 
 void __asan_describe_address(uptr addr) {