Embind: Fix C++ UNO exception catching

...with a new Module.catchUnoException JS function that can be used in a JS
catch block to provide the thrown UNO exception as an Any.  (For a non-C++
exception, it rethrows the exception, and for a non-UNO C++ exception it maps it
to css.uno.RuntimeException.)

The implementation reuses parts of bridges/source/cpp_uno/gcc3_wasm/, which have
been moved to a new StaticLibrary_emscriptencxxabi.

Change-Id: I708fe6121c43a1b9736de5dff449f6c4f32a45f3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/169325
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>

1 files changed, 107 insertions, 0 deletions

diff --git a/include/bridges/emscriptencxxabi/cxxabi.hxx b/include/bridges/emscriptencxxabi/cxxabi.hxx
new file mode 100644
index 000000000000..8c380961cb60
--- /dev/null
+++ b/include/bridges/emscriptencxxabi/cxxabi.hxx
@@ -0,0 +1,107 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <sal/config.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <exception>
+#include <typeinfo>
+
+#include <cxxabi.h>
+
+#include <config_cxxabi.h>
+#include <rtl/ustring.hxx>
+
+#if !HAVE_CXXABI_H_CXA_EXCEPTION
+
+// <https://github.com/emscripten-core/emscripten/>, system/lib/libunwind/include/unwind_itanium.h,
+// except where MODIFIED:
+typedef std::/*MODIFIED*/ uint64_t _Unwind_Exception_Class;
+struct _Unwind_Exception
+{
+    _Unwind_Exception_Class exception_class;
+    void (*exception_cleanup)(/*MODIFIED: _Unwind_Reason_Code reason, _Unwind_Exception* exc*/);
+#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+    std::/*MODIFIED*/ uintptr_t private_[6];
+#elif !defined(__USING_WASM_EXCEPTIONS__)
+    std::/*MODIFIED*/ uintptr_t private_1; // non-zero means forced unwind
+    std::/*MODIFIED*/ uintptr_t private_2; // holds sp that phase1 found for phase2 to use
+#endif
+#if __SIZEOF_POINTER__ == 4
+    // The implementation of _Unwind_Exception uses an attribute mode on the
+    // above fields which has the side effect of causing this whole struct to
+    // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
+    // pad fields added for binary compatibility.
+    std::/*MODIFIED*/ uint32_t reserved[3];
+#endif
+    // The Itanium ABI requires that _Unwind_Exception objects are "double-word
+    // aligned".  GCC has interpreted this to mean "use the maximum useful
+    // alignment for the target"; so do we.
+} __attribute__((__aligned__));
+
+// <https://github.com/emscripten-core/emscripten/>, system/lib/libcxxabi/src/cxa_exception.h,
+// except where MODIFIED:
+namespace __cxxabiv1
+{
+struct __cxa_exception
+{
+#if defined(__LP64__) || defined(_WIN64) || defined(_LIBCXXABI_ARM_EHABI)
+    // Now _Unwind_Exception is marked with __attribute__((aligned)),
+    // which implies __cxa_exception is also aligned. Insert padding
+    // in the beginning of the struct, rather than before unwindHeader.
+    void* reserve;
+    // This is a new field to support C++11 exception_ptr.
+    // For binary compatibility it is at the start of this
+    // struct which is prepended to the object thrown in
+    // __cxa_allocate_exception.
+    std::/*MODIFIED*/ size_t referenceCount;
+#endif
+    //  Manage the exception object itself.
+    std::type_info* exceptionType;
+#if 1 //MODIFIED: #ifdef __USING_WASM_EXCEPTIONS__
+    // In wasm, destructors return their argument
+    void*(/*MODIFIED: _LIBCXXABI_DTOR_FUNC*/ *exceptionDestructor)(void*);
+#else
+    void(/*MODIFIED: _LIBCXXABI_DTOR_FUNC*/ *exceptionDestructor)(void*);
+#endif
+    void* /*MODIFIED: std::unexpected_handler*/ unexpectedHandler;
+    std::terminate_handler terminateHandler;
+    __cxa_exception* nextException;
+    int handlerCount;
+#if defined(_LIBCXXABI_ARM_EHABI)
+    __cxa_exception* nextPropagatingException;
+    int propagationCount;
+#else
+    int handlerSwitchValue;
+    const unsigned char* actionRecord;
+    const unsigned char* languageSpecificData;
+    void* catchTemp;
+    void* adjustedPtr;
+#endif
+#if !defined(__LP64__) && !defined(_WIN64) && !defined(_LIBCXXABI_ARM_EHABI)
+    // This is a new field to support C++11 exception_ptr.
+    // For binary compatibility it is placed where the compiler
+    // previously added padding to 64-bit align unwindHeader.
+    std::/*MODIFIED*/ size_t referenceCount;
+#endif
+    _Unwind_Exception unwindHeader;
+};
+}
+
+#endif
+
+namespace emscriptencxxabi
+{
+OUString toUnoName(char const* name);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */