[sanitizer] Implement a __asan_default_options() equivalent for Scudo

Summary:
Currently, the Scudo Hardened Allocator only gets its flags via the SCUDO_OPTIONS environment variable.
With this patch, we offer the opportunity for programs to define their own options via __scudo_default_options() which behaves like __asan_default_options() (weak symbol).
A relevant test has been added as well, and the documentation updated accordingly.
I also used this patch as an opportunity to rename a few variables to comply with the LLVM naming scheme, and replaced a use of Report with dieWithMessage for consistency (and to avoid a callback).

Reviewers: llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D23018

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@277536 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 0 deletions

diff --git a/test/scudo/options.cpp b/test/scudo/options.cpp
new file mode 100644
index 000000000..bccf7c8fb
--- /dev/null
+++ b/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* __scudo_default_options() {
+  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