[AIX] report_fatal_error on `-fregister_global_dtors_with_atexit` for static init

[Xiangling_L]

Summary

On AIX, the semantic of global_dtors contains __sterm functions associated with C++ cleanup actions and user-declared __attribute__((__destructor__)) functions. We should never merely register __sterm with atexit(), so currently -fregister_global_dtors_with_atexit does not work well on AIX: It would cause finalization actions to not occur when unloading shared libraries. We need to figure out a way to handle that when we start supporting user-declared __attribute__((__destructor__)) functions.

Currently we report_fatal_error on this option temporarily.

[jasonliu]

LGTM with minor nit.

clang/test/CodeGenCXX/aix-sinit-register-global-dtors-with-atexit.cpp

10

nit: fix clang-format warning.

[hubert.reinterpretcast]

clang/lib/CodeGen/CodeGenModule.cpp

1212

This should query if the platform uses sinit/sterm.

[Xiangling_L]

Adjust the query;

[hubert.reinterpretcast]

LGTM; thanks.

clang/lib/CodeGen/CodeGenModule.cpp

void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority,
   // FIXME: Type coercion of void()* types.
   GlobalCtors.push_back(Structor(Priority, Ctor, AssociatedData));
 }
 
 /// AddGlobalDtor - Add a function to the list that will be called
 /// when the module is unloaded.
 void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority) {
   if (CodeGenOpts.RegisterGlobalDtorsWithAtExit) {
+    if (getContext().getTargetInfo().getTriple().isOSAIX())
+      llvm::report_fatal_error(
+          "register global dtors with atexit() is not supported on AIX yet");
     DtorsUsingAtExit[Priority].push_back(Dtor);
     return;
   }
 
   // FIXME: Type coercion of void()* types.
   GlobalDtors.push_back(Structor(Priority, Dtor, nullptr));
 }
 

clang/test/CodeGenCXX/aix-sinit-register-global-dtors-with-atexit.cpp

+// RUN: not %clang_cc1 -triple powerpc-ibm-aix-xcoff -S -emit-llvm -x c++ \
+// RUN:     -fregister-global-dtors-with-atexit < %s 2>&1 | \
+// RUN:   FileCheck %s
+
+// RUN: not %clang_cc1 -triple powerpc64-ibm-aix-xcoff -S -emit-llvm -x c++ \
+// RUN:     -fregister-global-dtors-with-atexit < %s 2>&1 | \
+// RUN:   FileCheck %s
+
+struct T{
+    T();
+    ~T();
+} t;
+
+// CHECK: error in backend: register global dtors with atexit() is not supported on AIX yet

clang/test/Driver/cxa-atexit.cpp

 // RUN: %clang -target x86_64-apple-darwin -fregister-global-dtors-with-atexit -fno-register-global-dtors-with-atexit -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
 // RUN: %clang -target x86_64-apple-darwin -fno-register-global-dtors-with-atexit -fregister-global-dtors-with-atexit -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHATEXIT %s
 // RUN: %clang -target x86_64-apple-darwin -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHATEXIT %s
 // RUN: %clang -target x86_64-apple-darwin -c -mkernel -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
+
 // RUN: %clang -target x86_64-pc-linux-gnu -fregister-global-dtors-with-atexit -fno-register-global-dtors-with-atexit -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
 // RUN: %clang -target x86_64-pc-linux-gnu -fno-register-global-dtors-with-atexit -fregister-global-dtors-with-atexit -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHATEXIT %s
 // RUN: %clang -target x86_64-pc-linux-gnu -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
 
+// RUN: %clang -target powerpc-ibm-aix-xcoff -fregister-global-dtors-with-atexit -fno-register-global-dtors-with-atexit -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -fno-register-global-dtors-with-atexit -fregister-global-dtors-with-atexit -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHATEXIT %s
+// RUN: %clang -target powerpc-ibm-aix-xcoff -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
+// RUN: %clang -target powerpc64-ibm-aix-xcoff -fregister-global-dtors-with-atexit -fno-register-global-dtors-with-atexit -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
+// RUN: %clang -target powerpc64-ibm-aix-xcoff -fno-register-global-dtors-with-atexit -fregister-global-dtors-with-atexit -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHATEXIT %s
+// RUN: %clang -target powerpc64-ibm-aix-xcoff -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=WITHOUTATEXIT %s
+
 // WITHATEXIT: -fregister-global-dtors-with-atexit
 // WITHOUTATEXIT-NOT: -fregister-global-dtors-with-atexit