These registers are only available on a limited set of ARM targets (those
based on XScale). Other targets should not have to pay the cost of these.
This patch shaves off about ~300 bytes of stack usage and ~1KB of code-size.
Differential revision: http://reviews.llvm.org/D21991
Reviewers: bcraig, compnerd
Change-Id: I2d7a1911a193bd70b123e78747e1a7d1482463c7
llvm-svn: 274744
Summary:
This patch changes the libunwind CMake so that it adds certain target flags like '-m32' or '--gcc-toolchain' before including config-ix.cmake.
Since these flags can affect things like check_library_exists([...]) they needed to be added before the tests are performed.
Additionally this patch adds LIBUNWIND_BUILD_32_BITS which defaults to LLVM_BUILD_32_BITS.
This patch fixes:
https://llvm.org/bugs/show_bug.cgi?id=27950https://llvm.org/bugs/show_bug.cgi?id=27959
Reviewers: jroelofs, danalbert, bcraig, rmaprath, compnerd
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D20889
llvm-svn: 271458
Cross unwinding requires larger sizes for unw_context_t and unw_cursor_t
buffers (large enough to hold the VRS of any architecture). This is not
desirable for the most common situation where libunwind is used for native
unwinding only.
This patch makes native unwinding the default build configuration. This
will start testing the tigher (compile-time) bounds of unw_context_t
and unw_cursor_t buffers for each architecture.
Change-Id: Ic61c476a75603ca4812959c233cfe56f83dc0b00
llvm-svn: 270972
Currently libunwind is built to support cross-unwinding [1] by default, which
requires the buffers unw_context_t and unw_cursor_t to be large enough to hold
the vritual register set (VRS) of any supported architecture. This is not
desirable for some platforms where the stack usage of the unwinder needs
to be kept to a minimum (e.g. bare-metal targets). The current patch introduces
a native-only (-DLIBUNWIND_ENABLE_CROSS_UNWINDING=OFF) unwinder variant that
adopts strict sizes for the buffers unw_context_t and unw_cursor_t depending
on the target architecture.
[1] http://www.nongnu.org/libunwind/man/libunwind(3).html#section_4
Change-Id: I380fff9a56c16a0fc520e3b1d8454a34b4a48373
llvm-svn: 270692
This replicates most of the build infrastructure from libc++abi ported to
libunwind. This allows building libunwind without requiring libc++abi.
llvm-svn: 235795
Asiri Rathnayake