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--- bridges/source/cpp_uno/gcc3_linux_powerpc64/except.cxx.orig 2022-03-23 13:32:00 UTC |
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+++ bridges/source/cpp_uno/gcc3_linux_powerpc64/except.cxx |
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@@ -189,10 +189,63 @@ type_info * RTTI::getRTTI( typelib_CompoundTypeDescrip |
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return rtti; |
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} |
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|
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- |
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+extern "C" |
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static void deleteException( void * pExc ) |
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{ |
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__cxa_exception const * header = ((__cxa_exception const *)pExc - 1); |
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+#if 1 |
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+ // First, the libcxxabi commit |
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+ // <http://llvm.org/viewvc/llvm-project?view=revision&revision=303175> |
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+ // "[libcxxabi] Align unwindHeader on a double-word boundary" towards |
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+ // LLVM 5.0 changed the size of __cxa_exception by adding |
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+ // |
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+ // __attribute__((aligned)) |
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+ // |
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+ // to the final member unwindHeader, on x86-64 effectively adding a hole of |
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+ // size 8 in front of that member (changing its offset from 88 to 96, |
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+ // sizeof(__cxa_exception) from 120 to 128, and alignof(__cxa_exception) |
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+ // from 8 to 16); the "header1" hack below to dynamically determine whether we run against a |
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+ // LLVM 5 libcxxabi is to look at the exceptionDestructor member, which must |
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+ // point to this function (the use of __cxa_exception in fillUnoException is |
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+ // unaffected, as it only accesses members towards the start of the struct, |
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+ // through a pointer known to actually point at the start). The libcxxabi commit |
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+ // <https://github.com/llvm/llvm-project/commit/9ef1daa46edb80c47d0486148c0afc4e0d83ddcf> |
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+ // "Insert padding before the __cxa_exception header to ensure the thrown" in LLVM 6 |
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+ // removes the need for this hack, so the "header1" hack can be removed again once we can be |
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+ // sure that we only run against libcxxabi from LLVM >= 6. |
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+ // |
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+ // Second, the libcxxabi commit |
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+ // <https://github.com/llvm/llvm-project/commit/674ec1eb16678b8addc02a4b0534ab383d22fa77> |
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+ // "[libcxxabi] Insert padding in __cxa_exception struct for compatibility" in LLVM 10 changed |
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+ // the layout of the start of __cxa_exception to |
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+ // |
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+ // [8 byte void *reserve] |
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+ // 8 byte size_t referenceCount |
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+ // |
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+ // so the "header2" hack below to dynamically determine whether we run against a LLVM >= 10 |
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+ // libcxxabi is to look whether the exceptionDestructor (with its known value) has increased its |
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+ // offset by 8. As described in the definition of __cxa_exception |
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+ // (bridges/source/cpp_uno/gcc3_linux_x86-64/share.hxx), the "header2" hack (together with the |
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+ // "#if 0" in the definition of __cxa_exception and the corresponding hack in fillUnoException) |
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+ // can be dropped once we can be sure that we only run against new libcxxabi that has the |
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+ // reserve member. |
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+ if (header->exceptionDestructor != &deleteException) { |
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+ auto const header1 = reinterpret_cast<__cxa_exception const *>( |
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+ reinterpret_cast<char const *>(header) - 8); |
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+ if (header1->exceptionDestructor == &deleteException) { |
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+ header = header1; |
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+ } else { |
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+ auto const header2 = reinterpret_cast<__cxa_exception const *>( |
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+ reinterpret_cast<char const *>(header) + 8); |
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+ if (header2->exceptionDestructor == &deleteException) { |
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+ header = header2; |
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+ } else { |
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+ assert(false); |
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+ } |
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+ } |
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+ } |
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+#endif |
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+ assert(header->exceptionDestructor == &deleteException); |
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typelib_TypeDescription * pTD = 0; |
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OUString unoName( toUNOname( header->exceptionType->name() ) ); |
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::typelib_typedescription_getByName( &pTD, unoName.pData ); |