[HWASAN] Make new/delete weak

[evgeny777]

Summary

This allows instrumenting executables with overridden new/delete. The approach was discussed in D54905

[eugenis]

LGTM

compiler-rt/trunk/lib/hwasan/hwasan_new_delete.cpp

 
 // TODO(alekseys): throw std::bad_alloc instead of dying on OOM.
 #define OPERATOR_NEW_BODY(nothrow) \
   GET_MALLOC_STACK_TRACE; \
   void *res = hwasan_malloc(size, &stack);\
   if (!nothrow && UNLIKELY(!res)) ReportOutOfMemory(size, &stack);\
   return res
 
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void *operator new(size_t size) { OPERATOR_NEW_BODY(false /*nothrow*/); }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void *operator new[](size_t size) { OPERATOR_NEW_BODY(false /*nothrow*/); }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void *operator new(size_t size, std::nothrow_t const&) {
   OPERATOR_NEW_BODY(true /*nothrow*/);
 }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void *operator new[](size_t size, std::nothrow_t const&) {
   OPERATOR_NEW_BODY(true /*nothrow*/);
 }
 
 #define OPERATOR_DELETE_BODY \
   GET_MALLOC_STACK_TRACE; \
   if (ptr) hwasan_free(ptr, &stack)
 
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void operator delete(void *ptr) NOEXCEPT { OPERATOR_DELETE_BODY; }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void operator delete[](void *ptr) NOEXCEPT { OPERATOR_DELETE_BODY; }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void operator delete(void *ptr, std::nothrow_t const&) { OPERATOR_DELETE_BODY; }
-INTERCEPTOR_ATTRIBUTE
+INTERCEPTOR_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 void operator delete[](void *ptr, std::nothrow_t const&) {
   OPERATOR_DELETE_BODY;
 }
 
 #endif // HWASAN_REPLACE_OPERATORS_NEW_AND_DELETE

compiler-rt/trunk/test/hwasan/TestCases/override-new-delete.cpp

+// RUN: %clangxx_hwasan %s
+#include <stddef.h>
+#include <new>
+
+char *__dummy;
+
+void *operator new(size_t size) { return __dummy; }
+void *operator new[](size_t size) { return __dummy; }
+void *operator new(size_t size, std::nothrow_t const&) noexcept { 
+  return __dummy; 
+}
+void *operator new[](size_t size, std::nothrow_t const&) noexcept { 
+  return __dummy; 
+}
+
+void operator delete(void *ptr) noexcept {}
+void operator delete[](void *ptr) noexcept {}
+void operator delete(void *ptr, std::nothrow_t const&) noexcept {}
+void operator delete[](void *ptr, std::nothrow_t const&) noexcept {}
+
+int main() {
+  return 0;  
+}