UB: reinterpret_cast pointer without using launder

Signed-off-by: wineway <[email protected]>
google · Dec 6, 2023 · e40943c · e40943c
1 parent 068d5ee
commit e40943c
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Showing 3 changed files with 8 additions and 2 deletions.
diff --git a/include/leveldb/env.h b/include/leveldb/env.h
@@ -39,6 +39,12 @@
 #endif  // defined(DeleteFile)
 #endif  // defined(_WIN32)
 
+#ifdef __cpp_lib_launder
+#define LAUNDER(x) std::launder((x))
+#else
+#define LAUNDER(x) x
+#endif
+
 namespace leveldb {
 
 class FileLock;

diff --git a/util/env_posix.cc b/util/env_posix.cc
@@ -883,7 +883,7 @@ class SingletonEnv {
   SingletonEnv(const SingletonEnv&) = delete;
   SingletonEnv& operator=(const SingletonEnv&) = delete;
 
-  Env* env() { return reinterpret_cast<Env*>(&env_storage_); }
+  Env* env() { return LAUNDER(reinterpret_cast<Env*>(&env_storage_)); }
 
   static void AssertEnvNotInitialized() {
 #if !defined(NDEBUG)

diff --git a/util/env_windows.cc b/util/env_windows.cc
@@ -778,7 +778,7 @@ class SingletonEnv {
   SingletonEnv(const SingletonEnv&) = delete;
   SingletonEnv& operator=(const SingletonEnv&) = delete;
 
-  Env* env() { return reinterpret_cast<Env*>(&env_storage_); }
+  Env* env() { return LAUNDER(reinterpret_cast<Env*>(&env_storage_)); }
 
   static void AssertEnvNotInitialized() {
 #if !defined(NDEBUG)