[AArch64] Return the correct size for TLSDESC_CALLSEQ
The branch relaxation pass is computing the wrong offsets because it assumes
TLSDESC_CALLSEQ eats up 4 bytes, when in fact it is lowered to an instruction
sequence taking up 16 bytes. This can become a problem in huge files with lots
of TLS accesses, as it may slowly move branch targets out of the range computed
by the branch relaxation pass.
Fixes PR24234 https://llvm.org/bugs/show_bug.cgi?id=24234
Differential Revision: https://reviews.llvm.org/D22870
This fixes "error in backend: fixup value out of range" when compiling
the misc/talkfilters port for AArch64.
Reported by: sbruno
PR: 201762
MFC after: 3 days
As is described at http://llvm.org/bugs/show_bug.cgi?id=22408, the GNU
linkers ld.bfd and ld.gold currently only support a subset of the
whole range of AArch64 ELF TLS relocations. Furthermore, they assume
that some of the code sequences to access thread-local variables are
produced in a very specific sequence. When the sequence is not as the
linker expects, it can silently mis-relaxe/mis-optimize the
instructions.
Even if that wouldn't be the case, it's good to produce the exact
sequence, as that ensures that linkers can perform optimizing
relaxations.
This patch:
* implements support for 16MiB TLS area size instead of 4GiB TLS area
size. Ideally clang would grow an -mtls-size option to allow support
for both, but that's not part of this patch.
* by default doesn't produce local dynamic access patterns, as even
modern ld.bfd and ld.gold linkers do not support the associated
relocations. An option (-aarch64-elf-ldtls-generation) is added to
enable generation of local dynamic code sequence, but is off by
default.
* makes sure that the exact expected code sequence for local dynamic
and general dynamic accesses is produced, by making use of a new
pseudo instruction. The patch also removes two
(AArch64ISD::TLSDESC_BLR, AArch64ISD::TLSDESC_CALL) pre-existing
AArch64-specific pseudo SDNode instructions that are superseded by
the new one (TLSDESC_CALLSEQ).
Submitted by: Kristof Beyls
Differential Revision: https://reviews.freebsd.org/D2175
AArch64: add backend option to reserve x18 (platform register)
AAPCS64 says that it's up to the platform to specify whether x18 is
reserved, and a first step on that way is to add a flag controlling
it.
From: Andrew Turner <andrew@fubar.geek.nz>
Requested by: andrew
[Aarch64] Customer lowering of CTPOP to SIMD should check for NEON
availability
This ensures llvm's AArch64 backend does not emit floating point
instructions if they are disabled.
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
ISelDAG: spot chain cycles involving MachineNodes
Previously, the DAGISel function WalkChainUsers was spotting that it
had entered already-selected territory by whether a node was a
MachineNode (amongst other things). Since it's fairly common practice
to insert MachineNodes during ISelLowering, this was not the correct
check.
Looking around, it seems that other nodes get their NodeId set to -1
upon selection, so this makes sure the same thing happens to all
MachineNodes and uses that characteristic to determine whether we
should stop looking for a loop during selection.
This should fix PR15840.
Specifically, this fixes the long-standing assertion failure when
compiling the multimedia/gstreamer port on i386. Thanks to Tijl
Coosemans for his help in getting upstream to fix it.
Approved by: re (marius)
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.
