From 306f507f9d8655356598de7546b74a3c32cc1935 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Fri, 25 Jan 2019 15:34:52 -0800 Subject: [PATCH] toolchain: add variadic MI thunk support flag GCC uses thunk functions to adjust the 'this' pointer when calling C++ member functions in classes derived with multiple inheritance. Generation of thunk functions requires support from the compiler back end. In the absence of that support target-independent code in the C++ front end is used to generate thunk functions, but it does not support vararg functions. Support for this feature is currently missing in or1k and xtensa toolchains. Add hidden option BR2_TOOLCHAIN_SUPPORTS_VARIADIC_MI_THUNK that indicates presence of this feature in the toolchain. Add dependency to packages that require this feature to be built. Fixes: http://autobuild.buildroot.net/results/c9e660c764edbd7cf0ae54ab0f0f412464721446/ http://autobuild.buildroot.net/results/9a3bf4b411c418ea78d59e35d23ba865dd453890/ Signed-off-by: Max Filippov Signed-off-by: Thomas Petazzoni --- package/libtorrent-rasterbar/Config.in | 2 ++ toolchain/Config.in | 13 +++++++++++++ 2 files changed, 15 insertions(+) diff --git a/package/libtorrent-rasterbar/Config.in b/package/libtorrent-rasterbar/Config.in index aa986f2388..6c55085947 100644 --- a/package/libtorrent-rasterbar/Config.in +++ b/package/libtorrent-rasterbar/Config.in @@ -1,4 +1,5 @@ comment "libtorrent-rasterbar needs a toolchain w/ C++, threads, wchar, gcc >= 4.8" + depends on BR2_TOOLCHAIN_SUPPORTS_VARIADIC_MI_THUNK depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_HAS_THREADS || !BR2_USE_WCHAR || \ !BR2_HOST_GCC_AT_LEAST_4_8 || !BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 @@ -8,6 +9,7 @@ config BR2_PACKAGE_LIBTORRENT_RASTERBAR depends on BR2_HOST_GCC_AT_LEAST_4_8 depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 depends on BR2_TOOLCHAIN_HAS_THREADS # boost + depends on BR2_TOOLCHAIN_SUPPORTS_VARIADIC_MI_THUNK depends on BR2_USE_WCHAR # boost select BR2_PACKAGE_BOOST select BR2_PACKAGE_BOOST_CHRONO diff --git a/toolchain/Config.in b/toolchain/Config.in index 275f9f9cdd..bcbc3cf984 100644 --- a/toolchain/Config.in +++ b/toolchain/Config.in @@ -100,6 +100,19 @@ config BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS depends on !BR2_sparc_v8 depends on !BR2_m68k_cf5208 +# GCC uses thunk functions to adjust the 'this' pointer when calling +# C++ member functions in classes derived with multiple inheritance. +# Generation of thunk functions requires support from the compiler +# back end. In the absence of that support target-independent code +# in the C++ front end is used to generate thunk functions, but it +# does not support vararg functions. +# or1k will support it in the gcc mainline starting with gcc-9. +config BR2_TOOLCHAIN_SUPPORTS_VARIADIC_MI_THUNK + bool + default y + depends on !BR2_or1k + depends on !BR2_xtensa + # Prior to gcc 7.x, exception_ptr, nested_exception and future from # libstdc++ would only be provided on architectures that support # always lock-free atomic ints. See -- 2.30.2