[Msan] Fix the backtrace.cc tests to build and pass on FreeBSD

[eugenis]

LGTM

test/msan/backtrace.cc

20

You could also use %zu.

lib/sanitizer_common/sanitizer_platform_interceptors.h

#define SANITIZER_INTERCEPT_WORDEXP \
   SI_FREEBSD || (SI_MAC && !SI_IOS) || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_SIGWAIT SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_SIGWAITINFO SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_SIGTIMEDWAIT SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_SIGSETOPS \
   SI_FREEBSD || SI_MAC || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_SIGPENDING SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_SIGPROCMASK SI_NOT_WINDOWS
-#define SANITIZER_INTERCEPT_BACKTRACE SI_LINUX_NOT_ANDROID
+#define SANITIZER_INTERCEPT_BACKTRACE SI_FREEBSD || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_GETMNTENT SI_LINUX
 #define SANITIZER_INTERCEPT_GETMNTENT_R SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_STATFS SI_FREEBSD || SI_MAC || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_STATFS64 \
   (SI_MAC && !SI_IOS) || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_STATVFS SI_FREEBSD || SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_STATVFS64 SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_INITGROUPS SI_NOT_WINDOWS

test/msan/backtrace.cc

void f() {
   int sz = backtrace(buf, sizeof(buf) / sizeof(*buf));
   assert(sz > 0);
   for (int i = 0; i < sz; ++i)
     if (!buf[i])
       exit(1);
   char **s = backtrace_symbols(buf, sz);
   assert(s > 0);
   for (int i = 0; i < sz; ++i)
-    printf("%d\n", strlen(s[i]));
+    printf("%d\n", (int)strlen(s[i]));
 }
 
 int main(void) {
   f();
   return 0;
 }

test/msan/lit.cfg

 # -*- Python -*-
 
 import os
 
 # Setup config name.
 config.name = 'MemorySanitizer'
 
 # Setup source root.
 config.test_source_root = os.path.dirname(__file__)
 
 # Setup default compiler flags used with -fsanitize=memory option.
 clang_msan_cflags = ["-fsanitize=memory",
                      "-mno-omit-leaf-frame-pointer",
                      "-fno-omit-frame-pointer",
                      "-fno-optimize-sibling-calls",
                      "-m64"] + config.debug_info_flags
+# Some Msan tests leverage backtrace() which requires libexecinfo on FreeBSD.
+if config.host_os == 'FreeBSD':
+  clang_msan_cflags += ["-lexecinfo"]
 clang_msan_cxxflags = config.cxx_mode_flags + clang_msan_cflags
 
 def build_invocation(compile_flags):
   return " " + " ".join([config.clang] + compile_flags) + " "
 
 config.substitutions.append( ("%clang_msan ", build_invocation(clang_msan_cflags)) )
 config.substitutions.append( ("%clangxx_msan ", build_invocation(clang_msan_cxxflags)) )
 
 # Default test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp']
 
 # MemorySanitizer tests are currently supported on Linux only.
 if config.host_os not in ['Linux']:
   config.unsupported = True