Introduce CGCXXABI::canCallMismatchedFunctionType

llvm-svn: 269089

3 files changed, 16 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGCXXABI.h b/clang/lib/CodeGen/CGCXXABI.h
index 3f240b1802b..8c0f6c2efd5 100644
--- a/clang/lib/CodeGen/CGCXXABI.h
+++ b/clang/lib/CodeGen/CGCXXABI.h
@@ -106,6 +106,16 @@ public:
 
   virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
 
+  /// Returns true if the target allows calling a function through a pointer
+  /// with a different signature than the actual function (or equivalently,
+  /// bitcasting a function or function pointer to a different function type).
+  /// In principle in the most general case this could depend on the target, the
+  /// calling convention, and the actual types of the arguments and return
+  /// value. Here it just means whether the signature mismatch could *ever* be
+  /// allowed; in other words, does the target do strict checking of signatures
+  /// for all calls.
+  virtual bool canCallMismatchedFunctionType() const { return true; }
+
   /// If the C++ ABI requires the given type be returned in a particular way,
   /// this method sets RetAI and returns true.
   virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0;
diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index 46d92ec46c4..89d142e44b4 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -88,11 +88,12 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
 
   // Special-case non-array C++ destructors, if they have the right signature.
   // Under some ABIs, destructors return this instead of void, and cannot be
-  // passed directly to __cxa_atexit.
+  // passed directly to __cxa_atexit if the target does not allow this mismatch.
   const CXXRecordDecl *Record = type->getAsCXXRecordDecl();
-  bool CanRegisterDestructor = Record &&
-                               !CGM.getCXXABI().HasThisReturn(GlobalDecl(
-                                   Record->getDestructor(), Dtor_Complete));
+  bool CanRegisterDestructor =
+      Record && (!CGM.getCXXABI().HasThisReturn(
+                     GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
+                 CGM.getCXXABI().canCallMismatchedFunctionType());
   // If __cxa_atexit is disabled via a flag, a different helper function is
   // generated elsewhere which uses atexit instead, and it takes the destructor
   // directly.
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 52e519f3044..4da7b9498f6 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -443,6 +443,7 @@ private:
            (isa<CXXDestructorDecl>(GD.getDecl()) &&
             GD.getDtorType() != Dtor_Deleting);
   }
+  bool canCallMismatchedFunctionType() const override { return false; }
 };
 }