to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Previously PredicateControl in some cases was a member of <X>Inst classes
for some X (DSP, EVA) or was in more irregular place in the hierarchry
for any given instruction.
This patch moves PredicateControl down to the root so that it is consistently
available. Then correct the base class of microMIPS instructions as using
EncodingPredicates instead of the general Predicates field of Instruction.
Reviewers: smaksimovic, abeserminji, atanasyan
Differential Revision: https://reviews.llvm.org/D47526
llvm-svn: 333536
This simplifies tagging instructions with the correct ISA and ASE, albeit making
instruction definitions a bit more verbose.
Reviewers: atanasyan, abeserminji
Differential Revision: https://reviews.llvm.org/D44299
llvm-svn: 327265
This patch provides mitigation for CVE-2017-5715, Spectre variant two,
which affects the P5600 and P6600. It implements the LLVM part of
-mindirect-jump=hazard. It is _not_ enabled by default for the P5600.
The migitation strategy suggested by MIPS for these processors is to use
hazard barrier instructions. 'jalr.hb' and 'jr.hb' are hazard
barrier variants of the 'jalr' and 'jr' instructions respectively.
These instructions impede the execution of instruction stream until
architecturally defined hazards (changes to the instruction stream,
privileged registers which may affect execution) are cleared. These
instructions in MIPS' designs are not speculated past.
These instructions are used with the attribute +use-indirect-jump-hazard
when branching indirectly and for indirect function calls.
These instructions are defined by the MIPS32R2 ISA, so this mitigation
method is not compatible with processors which implement an earlier
revision of the MIPS ISA.
Performance benchmarking of this option with -fpic and lld using
-z hazardplt shows a difference of overall 10%~ time increase
for the LLVM testsuite. Certain benchmarks such as methcall show a
substantially larger increase in time due to their nature.
Reviewers: atanasyan, zoran.jovanovic
Differential Revision: https://reviews.llvm.org/D43486
llvm-svn: 325653
passes in the mips back end. This, unfortunately, required a
bit of churn in the various predicates to use a pointer rather
than a reference.
llvm-svn: 212744
Chandler Carruth