Index: projects/compiler-rt/lib/scudo/scudo_allocator.cpp
===================================================================
--- projects/compiler-rt/lib/scudo/scudo_allocator.cpp
+++ projects/compiler-rt/lib/scudo/scudo_allocator.cpp
@@ -76,7 +76,7 @@
   u64 Offset        : 20; // Offset from the beginning of the backend
                           // allocation to the beginning chunk itself, in
                           // multiples of MinAlignment. See comment about its
-                          // maximum value and test in Initialize.
+                          // maximum value and test in init().
   u64 Unused_1_     : 28;
   u16 Salt          : 16;
 };
Index: projects/compiler-rt/lib/scudo/scudo_flags.cpp
===================================================================
--- projects/compiler-rt/lib/scudo/scudo_flags.cpp
+++ projects/compiler-rt/lib/scudo/scudo_flags.cpp
@@ -17,9 +17,12 @@
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_flag_parser.h"
 
+extern "C" SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
+const char* getScudoDefaultOptions();
+
 namespace __scudo {
 
-Flags scudo_flags_dont_use_directly;  // use via flags().
+Flags ScudoFlags;  // Use via getFlags().
 
 void Flags::setDefaults() {
 #define SCUDO_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
@@ -34,6 +37,10 @@
 #undef SCUDO_FLAG
 }
 
+static const char *callGetScudoDefaultOptions() {
+  return (&getScudoDefaultOptions) ? getScudoDefaultOptions() : "";
+}
+
 void initFlags() {
   SetCommonFlagsDefaults();
   {
@@ -45,11 +52,16 @@
   Flags *f = getFlags();
   f->setDefaults();
 
-  FlagParser scudo_parser;
-  RegisterScudoFlags(&scudo_parser, f);
-  RegisterCommonFlags(&scudo_parser);
+  FlagParser ScudoParser;
+  RegisterScudoFlags(&ScudoParser, f);
+  RegisterCommonFlags(&ScudoParser);
+
+  // Override from user-specified string.
+  const char *ScudoDefaultOptions = callGetScudoDefaultOptions();
+  ScudoParser.ParseString(ScudoDefaultOptions);
 
-  scudo_parser.ParseString(GetEnv("SCUDO_OPTIONS"));
+  // Override from environment.
+  ScudoParser.ParseString(GetEnv("SCUDO_OPTIONS"));
 
   InitializeCommonFlags();
 
@@ -75,7 +87,7 @@
 }
 
 Flags *getFlags() {
-  return &scudo_flags_dont_use_directly;
+  return &ScudoFlags;
 }
 
 }
Index: projects/compiler-rt/test/scudo/options.cpp
===================================================================
--- projects/compiler-rt/test/scudo/options.cpp
+++ projects/compiler-rt/test/scudo/options.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_scudo %s -o %t
+// RUN:                                              %run %t 2>&1
+// RUN: SCUDO_OPTIONS=DeallocationTypeMismatch=0     %run %t 2>&1
+// RUN: SCUDO_OPTIONS=DeallocationTypeMismatch=1 not %run %t 2>&1 | FileCheck %s
+
+// Tests that the options can be passed using getScudoDefaultOptions, and that
+// the environment ones take precedence over them.
+
+#include <stdlib.h>
+#include <malloc.h>
+
+extern "C" const char* getScudoDefaultOptions() {
+  return "DeallocationTypeMismatch=0";  // Defaults to true in scudo_flags.inc.
+}
+
+int main(int argc, char **argv)
+{
+  int *p = (int *)malloc(16);
+  if (!p)
+    return 1;
+  delete p;
+  return 0;
+}
+
+// CHECK: ERROR: allocation type mismatch on address