Add ISD::EH_DWARF_CFA, simplify @llvm.eh.dwarf.cfa on Mips, fix on
PowerPC
LLVM has an @llvm.eh.dwarf.cfa intrinsic, used to lower the
GCC-compatible __builtin_dwarf_cfa() builtin. As pointed out in
PR26761, this is currently broken on PowerPC (and likely on ARM as
well). Currently, @llvm.eh.dwarf.cfa is lowered using:
ADD(FRAMEADDR, FRAME_TO_ARGS_OFFSET)
where FRAME_TO_ARGS_OFFSET defaults to the constant zero. On x86,
FRAME_TO_ARGS_OFFSET is lowered to 2*SlotSize. This setup, however,
does not work for PowerPC. Because of the way that the stack layout
works, the canonical frame address is not exactly (FRAMEADDR +
FRAME_TO_ARGS_OFFSET) on PowerPC (there is a lower save-area offset
as well), so it is not just a matter of implementing
FRAME_TO_ARGS_OFFSET for PowerPC (unless we redefine its semantics --
We can do that, since it is currently used only for
@llvm.eh.dwarf.cfa lowering, but the better to directly lower the CFA
construct itself (since it can be easily represented as a
fixed-offset FrameIndex)). Mips currently does this, but by using a
custom lowering for ADD that specifically recognizes the (FRAMEADDR,
FRAME_TO_ARGS_OFFSET) pattern.
This change introduces a ISD::EH_DWARF_CFA node, which by default
expands using the existing logic, but can be directly lowered by the
target. Mips is updated to use this method (which simplifies its
implementation, and I suspect makes it more robust), and updates
PowerPC to do the same.
Fixes PR26761.
Differential Revision: https://reviews.llvm.org/D24038
bugfix-only release, with no new features.
Please note that from 3.5.0 onwards, clang and llvm require C++11
support to build; see UPDATING for more information.
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.
The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3. The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.
Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>
MFC after: 1 month
upcoming 3.3 release (branching and freezing expected in a few weeks).
Preliminary release notes can be found at the usual location:
<http://llvm.org/docs/ReleaseNotes.html>
An MFC is planned once the actual 3.3 release is finished.
This commit merges the latest LLVM sources from the vendor space. It
also updates the build glue to match the new sources. Clang's version
number is changed to match LLVM's, which means /usr/include/clang/2.0
has been renamed to /usr/include/clang/2.8.
Obtained from: projects/clangbsd
