Abstract the emission of global destructors into ABI-specific code

and only consider using __cxa_atexit in the Itanium logic.  The
default logic is to use atexit().

Emit "guarded" initializers in Microsoft mode unconditionally.
This is definitely not correct, but it's closer to correct than
just not emitting the initializer.

Based on a patch by Timur Iskhodzhanov!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155894 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 62 deletions

diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index 10f0b83e40..a27516bb5b 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -98,7 +98,7 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
     argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
   }
 
-  CGF.EmitCXXGlobalDtorRegistration(function, argument);
+  CGM.getCXXABI().registerGlobalDtor(CGF, function, argument);
 }
 
 /// Emit code to cause the variable at the given address to be considered as
@@ -145,39 +145,6 @@ void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
   EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
 }
 
-/// Register a global destructor using __cxa_atexit.
-static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF,
-                                        llvm::Constant *dtor,
-                                        llvm::Constant *addr) {
-  // We're assuming that the destructor function is something we can
-  // reasonably call with the default CC.  Go ahead and cast it to the
-  // right prototype.
-  llvm::Type *dtorTy =
-    llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo();
-
-  // extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d);
-  llvm::Type *paramTys[] = { dtorTy, CGF.Int8PtrTy, CGF.Int8PtrTy };
-  llvm::FunctionType *atexitTy =
-    llvm::FunctionType::get(CGF.IntTy, paramTys, false);
-
-  // Fetch the actual function.
-  llvm::Constant *atexit =
-    CGF.CGM.CreateRuntimeFunction(atexitTy, "__cxa_atexit");
-  if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit))
-    fn->setDoesNotThrow();
-
-  // Create a variable that binds the atexit to this shared object.
-  llvm::Constant *handle =
-    CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle");
-
-  llvm::Value *args[] = {
-    llvm::ConstantExpr::getBitCast(dtor, dtorTy),
-    llvm::ConstantExpr::getBitCast(addr, CGF.Int8PtrTy),
-    handle
-  };
-  CGF.Builder.CreateCall(atexit, args);
-}
-
 static llvm::Function *
 CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
                                    llvm::FunctionType *ty,
@@ -212,43 +179,22 @@ static llvm::Constant *createAtExitStub(CodeGenModule &CGM,
   return fn;
 }
 
-/// Register a global destructor using atexit.
-static void emitGlobalDtorWithAtExit(CodeGenFunction &CGF,
-                                     llvm::Constant *dtor,
-                                     llvm::Constant *addr) {
+/// Register a global destructor using the C atexit runtime function.
+void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtor,
+                                                   llvm::Constant *addr) {
   // Create a function which calls the destructor.
-  llvm::Constant *dtorStub = createAtExitStub(CGF.CGM, dtor, addr);
+  llvm::Constant *dtorStub = createAtExitStub(CGM, dtor, addr);
 
   // extern "C" int atexit(void (*f)(void));
   llvm::FunctionType *atexitTy =
-    llvm::FunctionType::get(CGF.IntTy, dtorStub->getType(), false);
+    llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
 
   llvm::Constant *atexit =
-    CGF.CGM.CreateRuntimeFunction(atexitTy, "atexit");
+    CGM.CreateRuntimeFunction(atexitTy, "atexit");
   if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
     atexitFn->setDoesNotThrow();
 
-  CGF.Builder.CreateCall(atexit, dtorStub);
-}
-
-void CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *dtor,
-                                                    llvm::Constant *addr) {
-  // Use __cxa_atexit if available.
-  if (CGM.getCodeGenOpts().CXAAtExit) {
-    emitGlobalDtorWithCXAAtExit(*this, dtor, addr);
-    return;
-  }
-
-  // In Apple kexts, we want to add a global destructor entry.
-  // FIXME: shouldn't this be guarded by some variable?
-  if (CGM.getContext().getLangOpts().AppleKext) {
-    // Generate a global destructor entry.
-    CGM.AddCXXDtorEntry(dtor, addr);
-    return;
-  }
-
-  // Otherwise, we just use atexit.
-  emitGlobalDtorWithAtExit(*this, dtor, addr);
+  Builder.CreateCall(atexit, dtorStub)->setDoesNotThrow();
 }
 
 void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,