[asan] enable LeakSanitizer (LSan) by default in asan. This only affects Linux x86_64. LSan has been used in various projects for more than half a year and we now consider it quite stable to be on by default.

llvm-svn: 206896

compiler-rt/lib/asan/asan_rtl.cc

@@ -230,6 +230,7 @@ static void ParseFlagsFromString(Flags *f, const char *str) {
 void InitializeFlags(Flags *f, const char *env) {
   CommonFlags *cf = common_flags();
   SetCommonFlagsDefaults(cf);
+  cf->detect_leaks = CAN_SANITIZE_LEAKS;
   cf->external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
   cf->malloc_context_size = kDefaultMallocContextSize;
   cf->intercept_tls_get_addr = true;
@@ -288,13 +289,11 @@ void InitializeFlags(Flags *f, const char *env) {
     PrintFlagDescriptions();
   }
 
-#if !CAN_SANITIZE_LEAKS
-  if (cf->detect_leaks) {
+  if (!CAN_SANITIZE_LEAKS && cf->detect_leaks) {
     Report("%s: detect_leaks is not supported on this platform.\n",
            SanitizerToolName);
     cf->detect_leaks = false;
   }
-#endif
 
   // Make "strict_init_order" imply "check_initialization_order".
   // TODO(samsonov): Use a single runtime flag for an init-order checker.

compiler-rt/lib/sanitizer_common/sanitizer_flags.cc

@@ -40,7 +40,7 @@ void SetCommonFlagsDefaults(CommonFlags *f) {
   f->malloc_context_size = 1;
   f->log_path = "stderr";
   f->verbosity = 0;
-  f->detect_leaks = false;
+  f->detect_leaks = true;
   f->leak_check_at_exit = true;
   f->allocator_may_return_null = false;
   f->print_summary = true;

compiler-rt/test/asan/TestCases/Linux/leak.cc

@@ -0,0 +1,16 @@
+// Minimal test for LeakSanitizer+AddressSanitizer.
+// REQUIRES: asan-64-bits
+//
+// RUN: %clangxx_asan  %s -o %t
+// RUN: ASAN_OPTIONS=detect_leaks=1 not %t  2>&1 | FileCheck %s
+// RUN:                             not %t  2>&1 | FileCheck %s
+// RUN: ASAN_OPTIONS=detect_leaks=0     %t
+#include <stdio.h>
+int *t;
+
+int main(int argc, char **argv) {
+  t = new int[argc - 1];
+  printf("t: %p\n", t);
+  t = 0;
+}
+// CHECK: LeakSanitizer: detected memory leaks

compiler-rt/test/asan/TestCases/allocator_returns_null.cc

@@ -52,10 +52,12 @@ int main(int argc, char **argv) {
     *t = 42;
     x = (char*)realloc(t, size);
     assert(*t == 42);
+    free(t);
   }
   // The NULL pointer is printed differently on different systems, while (long)0
   // is always the same.
   fprintf(stderr, "x: %lx\n", (long)x);
+  free(x);
   return x != 0;
 }
 // CHECK-mCRASH: malloc:

compiler-rt/test/ubsan/TestCases/TypeCheck/vptr.cpp

@@ -31,6 +31,8 @@ struct T : S {
 
 struct U : S, T { virtual int v() { return 2; } };
 
+T *p = 0;  // Make p global so that lsan does not complain.
+
 int main(int, char **argv) {
   T t;
   (void)t.a;
@@ -49,7 +51,6 @@ int main(int, char **argv) {
   (void)u.T::v();
   (void)((T&)u).S::v();
 
-  T *p = 0;
   char Buffer[sizeof(U)] = {};
   switch (argv[1][1]) {
   case '0':