calypso should be usable with libc++ on OSX (clang on OSX should use that instead of libstdc++)

[timotheecour]

Calypso/runtime/calypso/cpp/eh/unwind-cxx.h uses #include <bits/atomic_word.h>

that's a libstdc++ file, but clang on OSX should use libc++ instead of libstdc++ (eg: https://discuss.codechef.com/questions/81564/bitsstdch-does-not-work-in-mac-os )

This is why we get errors such as:

ccmake -D LLVM_CONFIG=$homebrew_D/Cellar/llvm@3.9/3.9.1_1/bin/llvm-config -D D_FLAGS="-cpp-args=-I$homebrew_D/opt/llvm/include/c++/v1/" ..

Calypso/runtime/calypso/cpp/eh/unwind-cxx.h:38:10: fatal error: 'bits/atomic_word.h' file not found

NOTE: a workaround is to use gcc includes, eg: https://github.com/Syniurge/Calypso#installing-on-osx

related issues:

• Build Failure with Nix: fatal error: 'typeinfo' file not found #41
• OSX: building calypso gives: error: unknown type name '_Unwind_Ptr'  #76
• OS X build issue #34 (maybe)

unwind-cxx.h should be updated to be more portable, and on OSX not depend on bits/atomic_word.h

EDIT

with the following patch:

--- a/runtime/calypso/cpp/eh/unwind-cxx.h
+++ b/runtime/calypso/cpp/eh/unwind-cxx.h
@@ -35,7 +35,20 @@
 #include <exception>
 #include <cstddef>
 #include "unwind.h"
-#include <bits/atomic_word.h>
+
+// PRTEMP
+// #include <bits/atomic_word.h>
+typedef int _Atomic_word;
+// This is a memory order acquire fence.
+#define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE)
+// This is a memory order release fence.
+#define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE)
+#define _GLIBCXX_CDTOR_CALLABI
+// #if defined(__ia64__) && defined(__hpux__)
+typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
+typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));

I can build most of calypso via:

ccmake -D LLVM_CONFIG=$homebrew_D/Cellar/llvm@3.9/3.9.1_1/bin/llvm-config -D D_FLAGS="-cpp-args=-nostdinc;-cpp-args=-I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1;-cpp-args=-I/usr/include" ..

except for __is_pointer_p and __do_catch missing from type_info ; indeed, this is used:

/usr/include/c++/4.2.1/typeinfo

and that file contains modifications by APPLE to remove __do_catch, __is_pointer_p.

EDIT

indeed this was mentioned in https://syniurgeblog.wordpress.com/tag/c/ :

What’s essentially left to implement in Calypso:
libc++ doesn’t offer __do_catch(), an alternative is needed

[timotheecour]

also related: https://itanium-cxx-abi.github.io/cxx-abi/cxx-closed.html

[001012 all -- Jim] The issue here, raised originally by Martin, I will open as A-30. Implementations will generally need additional virtual functions associated with the type_info hierarchy to implement such functionality as dynamic cast. Gcc for instance has functions __is_function_p, __do_catch, __pointer_catch, ...

[timotheecour]

maybe something like this:
(inspired from https://github.com/llvm-mirror/libcxxabi/blob/master/src/cxa_default_handlers.cpp)
problem : private_typeinfo.h is not accessible directly, it's in https://github.com/llvm-mirror/libcxxabi/blob/master/src/private_typeinfo.h

+    bool doCatch(void* address, ubyte encoding)
+    {
+        void *__thr_obj = __get_object_from_ue(&_cpp_exception.unwindHeader);
+        const __shim_type_info* thrown_type = cast(const __shim_type_info*)(_cpp_exception.exceptionType);
+
+        auto catchTypeInfo = getCatchTypeInfo(address, encoding);
+        if(!catchTypeInfo) return false;
+        const __shim_type_info* catch_type = cast(const __shim_type_info*)(catchTypeInfo);
+        if (catch_type.can_catch(thrown_type, __thr_obj))
+        {
+            // NOTE: __cxa_begin_catch returns adjustedPtr, which in C++ EH is set by __gxx_personality_v0 if the search phase is successful
+            _cpp_exception.adjustedPtr = __thr_obj;
+            return true;
+        }
+
+        return false;
+    }

also requires:

--- a/runtime/CMakeLists.txt
+++ b/runtime/CMakeLists.txt
@@ -479,9 +479,10 @@ macro(build_runtime_libs druntime_o druntime_bc phobos2_o phobos2_bc calypsort_o
         LIBRARY_OUTPUT_DIRECTORY    ${output_path}
         RUNTIME_OUTPUT_DIRECTORY    ${output_path}
         COMPILE_FLAGS               "${c_flags}"
-        # fix for OSX
+        # fix for OSX PRTEMP
         #LINK_FLAGS                  "${ld_flags}"
-        LINK_FLAGS                  "${ld_flags} -L../lib -ldruntime-ldc${lib_suffix}"
+        #LINK_FLAGS                  "${ld_flags} -L../lib -ldruntime-ldc${lib_suffix}"
+        LINK_FLAGS                  "${ld_flags} -L../lib -ldruntime-ldc${lib_suffix} -lc++abi"
         LINKER_LANGUAGE             CXX
     )

to avoid link error:

Undefined symbols for architecture x86_64:
  "typeinfo for __cxxabiv1::__shim_type_info", referenced from:
      __D3cpp2eh3gnu10CppHandler7doCatchMFPvhZb in gnu-debug.o

as well as adding:
modmap (C++) "private_typeinfo.h";
and passing an addition -cpp-args=-I=path/libcxxabi/src/

EDIT: exception handling doesn't work though (same error as #87)

[Syniurge]

Good finds! This will ease fixing the OS X support.

(I vaguely remember quickly looking for an alternative to std::type_info::__do_catch in libc++ and didn't find it at that time)

[timotheecour]

fixed via 5aa7849 and 55de259 ; thanks!