Currently the DecoderEmitter constructor takes a bunch of string
parameters containing bits of code to interpolate.
However, there's only two ways it can be called. The one used for most
targets which doesn't handle the SoftFail DecoderStatus (not a
problem, because they don't use SoftFail). The other mode, which is
used for ARM/AArch64, does handle SoftFail, but requires an externally
defined helper function in those targets.
This is unnecessary complication; remove the parameters, and unify
onto a single version which does support SoftFail, defining the helper
itself.
The ABI for big-endian AArch32, as specified by AAELF32, is above-
averagely complicated. Relocatable object files are expected to store
instruction encodings in byte order matching the ELF file's endianness
(so, big-endian for a BE ELF file). But executable images can
//either// do that //or// store instructions little-endian regardless
of data and ELF endianness (to support BE32 and BE8 platforms
respectively). They signal the latter by setting the EF_ARM_BE8 flag
in the ELF header.
(In the case of the Thumb instruction set, this all means that each
16-bit halfword of a Thumb instruction is stored in one or other
endianness. The two halfwords of a 32-bit Thumb instruction must
appear in the same order no matter what, because the first halfword is
the one that must avoid overlapping the encoding of any 16-bit Thumb
instruction.)
llvm-objdump was unconditionally expecting Arm instructions to be
stored little-endian. So it would correctly disassemble a BE8 image,
but if you gave it a BE32 image or a BE object file, it would retrieve
every instruction in byte-swapped form and disassemble it to
nonsense. (Even an object file output by LLVM itself, because
ARMMCCodeEmitter outputs instructions big-endian in big-endian mode,
which is correct for writing an object file.)
This patch allows llvm-objdump to correctly disassemble all three of
those classes of Arm ELF file. It does it by introducing a new
SubtargetFeature for big-endian instructions, setting it from the ELF
image type and flags during llvm-objdump setup, and teaching both
ARMDisassembler and llvm-objdump itself to pay attention to it when
retrieving instruction data from a section being disassembled.
Differential Revision: https://reviews.llvm.org/D130902
Currently, when llvm-objdump is disassembling a code section and
encounters a point where no instruction can be decoded, it uses the
same policy on all targets: consume one byte of the section, emit it
as "<unknown>", and try disassembling from the next byte position.
On an architecture where instructions are always 4 bytes long and
4-byte aligned, this makes no sense at all. If a 4-byte word cannot be
decoded as an instruction, then the next place that a valid
instruction could //possibly// be found is 4 bytes further on.
Disassembling from a misaligned address can't possibly produce
anything that the code generator intended, or that the CPU would even
attempt to execute.
This patch introduces a new MCDisassembler virtual method called
`suggestBytesToSkip`, which allows each target to choose its own
resynchronization policy. For Arm (as opposed to Thumb) and AArch64,
I've filled in the new method to return a fixed width of 4.
Thumb is a more interesting case, because the criterion for
identifying 2-byte and 4-byte instruction encodings is very simple,
and doesn't require the particular instruction to be recognized. So
`suggestBytesToSkip` is also passed an ArrayRef of the bytes in
question, so that it can take that into account. The new test case
shows Thumb disassembly skipping over two unrecognized instructions,
and identifying one as 2-byte and one as 4-byte.
For targets other than Arm and AArch64, this is NFC: the base class
implementation of `suggestBytesToSkip` still returns 1, so that the
existing behavior is unchanged. Other targets can fill in their own
implementations as they see fit; I haven't attempted to choose a new
behavior for each one myself.
I've updated all the call sites of `MCDisassembler::getInstruction` in
llvm-objdump, and also one in sancov, which was the only other place I
spotted the same idiom of `if (Size == 0) Size = 1` after a call to
`getInstruction`.
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D130357
MCSymbolizer::tryAddingSymbolicOperand() overloaded the Size parameter
to specify either the instruction size or the operand size depending on
the architecture. However, for proper symbolic disassembly on X86, we
need to know both sizes, as an instruction can have two operands, and
the instruction size cannot be reliably calculated based on the operand
offset and its size. Hence, split Size into OpSize and InstSize.
For X86, the new interface allows to fix a couple of issues:
* Correctly adjust the value of PC-relative operands.
* Set operand size to zero when the operand is specified implicitly.
Differential Revision: https://reviews.llvm.org/D126101
The name `MCFixedLenDisassembler.h` is out of date after D120958.
Rename it as `MCDecoderOps.h` to reflect the change.
Reviewed By: myhsu
Differential Revision: https://reviews.llvm.org/D124987
All LLVM backends use MCDisassembler as a base class for their
instruction decoders. Use "const MCDisassembler *" for the decoder
instead of "const void *". Remove unnecessary static casts.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D122245
There is a crash in the ARM backend when attempting to decode a "tsb
csync" instruction using `llvm-objdump --triple=armv8.4a -d`. The crash
was in `ARMMCInstrAnalysis::evaluateBranch` where the number of operands
in the decoded instruction (0) did not match the number of operands in
the instruction description (1).
This is becuase `tsb csync` looks like it has an operand during
assembly, but there is only one valid operand (csync), so there is no
encoding space in the instruction for the operand, so the decoder never
has a field to decode that represents `csync`.
The fix is to add a custom decode method, which ensures that this
instruction does have the right number of operands after decoding. This
method merely adds the only available operand value, `ARM_TSB::CSYNC`.
Reviewed By: tmatheson
Differential Revision: https://reviews.llvm.org/D121479
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.
This allows us to ensure that Support doesn't have includes from MC/*.
Differential Revision: https://reviews.llvm.org/D111454
The semantics of tail predication loops means that the value of LR as an
instruction is executed determines the predicate. In other words:
mov r3, #3
DLSTP lr, r3 // Start tail predication, lr==3
VADD.s32 q0, q1, q2 // Lanes 0,1 and 2 are updated in q0.
mov lr, #1
VADD.s32 q0, q1, q2 // Only first lane is updated.
This means that the value of lr cannot be spilled and re-used in tail
predication regions without potentially altering the behaviour of the
program. More lanes than required could be stored, for example, and in
the case of a gather those lanes might not have been setup, leading to
alignment exceptions.
This patch adds a new lr predicate operand to MVE instructions in order
to keep a reference to the lr that they use as a tail predicate. It will
usually hold the zeroreg meaning not predicated, being set to the LR phi
value in the MVETPAndVPTOptimisationsPass. This will prevent it from
being spilled anywhere that it needs to be used.
A lot of tests needed updating.
Differential Revision: https://reviews.llvm.org/D107638
Similar to the MQPR register class as the MVE equivalent to QPR, this
adds MQQPR and MQQQQPR register classes for the MVE equivalents of QQPR
and QQQQPR registers. The MVE MQPR seemed have worked out quite well,
and adding MQQPR and MQQQQPR allows us to a little more accurately
specify the number of registers, calculating register pressure limits a
little better.
Differential Revision: https://reviews.llvm.org/D107463
Try to fix bug 49974.
This patch fixes two issues:
1. BL does not use predicate (BL_pred is the predicate version of BL),
so we shouldn't add predicate operands in DecodeBranchImmInstruction.
2. Inside DecodeT2AddSubSPImm, we shouldn't add predicate operands into
the MCInst because ARMDisassembler::AddThumbPredicate will do that for us.
However, we should handle CC-out operand for t2SUBspImm and t2AddspImm.
Differential Revision: https://reviews.llvm.org/D100585
2c196bbc6b asserted that
`SmallVector::push_back` doesn't invalidate the parameter when it needs
to grow. Do the same for `resize`, `append`, `assign`, `insert`, and
`emplace_back`.
Differential Revision: https://reviews.llvm.org/D91744
No longer rely on an external tool to build the llvm component layout.
Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.
These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.
Differential Revision: https://reviews.llvm.org/D90848
Summary:
This fixes Bugzilla #46616 in which it was reported
that "tbb [pc, r0]" was marked as SoftFail
(aka unpredictable) incorrectly.
Expected behaviour is:
* ARMv8 is required to use sp as rn or rm
(tbb/tbh only have a Thumb encoding so using Arm mode
is not an option)
* If rm is the pc then the instruction is always
unpredictable
Some of this was implemented already and this fixes the
rest. Added tests cover the new and pre-existing handling.
Reviewers: ostannard
Reviewed By: ostannard
Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D84227
From Arm v8 Architecture Reference Manual F5.1.84 LDREXD
The ldrexd instruction in Arm state has the following conditions:
t = UInt(Rt); t2 = t + 1; n = UInt(Rn);
if Rt<0> == '1' || t2 == 15 || n == 15 then UNPREDICTABLE;
In when Rt is odd or if Rt is 14 (making t2 15).
In the implementation when the pair is the UNPREDICTABLE R14_R15 we
would ideally return SOFT_FAIL. We can't because there is no R14_R15
value for us to return so we fail early returning FAIL.
The early return for registers outside the bounds of the table means
the check for Rt == 14 (0xE) redundant which causes a static analyzer
to flag the condition as never being true.
To fix the warning I've removed the check and replaced with a comment
explaining the difference with the specification.
Fixes pr41660
Differential Revision: https://reviews.llvm.org/D77463
Summary:
This patch adds assembly-level support for a new Arm M-profile
architecture extension, Custom Datapath Extension (CDE).
A brief description of the extension is available at
https://developer.arm.com/architectures/instruction-sets/custom-instructions
The latest specification for CDE is currently a beta release and is
available at
https://static.docs.arm.com/ddi0607/aa/DDI0607A_a_armv8m_arm_supplement_cde.pdf
CDE allows chip vendors to add custom CPU instructions. The CDE
instructions re-use the same encoding space as existing coprocessor
instructions (such as MRC, MCR, CDP etc.). Each coprocessor in range
cp0-cp7 can be configured as either general purpose (GCP) or custom
datapath (CDEv1). This configuration is defined by the CPU vendor and
is provided to LLVM using 8 subtarget features: cdecp0 ... cdecp7.
The semantics of CDE instructions are implementation-defined, but the
instructions are guaranteed to be pure (that is, they are stateless,
they do not access memory or any registers except their explicit
inputs/outputs).
CDE requires the CPU to support at least Armv8.0-M mainline
architecture. CDE includes 3 sets of instructions:
* Instructions that operate on general purpose registers and NZCV
flags
* Instructions that operate on the S or D register file (require
either FP or MVE extension)
* Instructions that operate on the Q register file, require MVE
The user-facing names that can be specified on the command line are
the same as the 8 subtarget feature names. For example:
$ clang -target arm-none-none-eabi -march=armv8m.main+cdecp0+cdecp3
tells the compiler that the coprocessors 0 and 3 are configured as
CDEv1 and the remaining coprocessors are configured as GCP (which is
the default).
Reviewers: simon_tatham, ostannard, dmgreen, eli.friedman
Reviewed By: simon_tatham
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D74044
Summary:
In NEON, the immediate forms of VBIC and VORR are each represented as
a single MC instruction, which takes its immediate operand already
encoded in a NEON-friendly format: 8 data bits, plus some control bits
indicating how to expand them into a full vector.
In MVE, we represented immediate VBIC and VORR as four separate MC
instructions each, for an 8-bit immediate shifted left by 0, 8, 16 or
24 bits. For each one, the value of the immediate operand is in the
'natural' form, i.e. the numerical value that would actually be BICed
or ORRed into each vector lane (and also the same value shown in
assembly). For example, MVE_VBICIZ16v4i32 takes an operand such as
0xab0000, which NEON would represent as 0xab | (control bits << 8).
The MVE approach is superficially nice (it makes assembly input and
output easy, and it's also nice if you're manually constructing
immediate VBICs). But it turns out that it's better for isel if we
make the NEON and MVE instructions work the same, because the
ARMISD::VBICIMM and VORRIMM node types already encode their immediate
into the NEON format, so it's easier if we can just use it.
Also, this commit reduces the total amount of code rather than
increasing it, which is surely an indication that it really is simpler
to do it this way!
Reviewers: dmgreen, ostannard, miyuki, MarkMurrayARM
Reviewed By: dmgreen
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73205
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.
A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.
This patch reduces the number of public symbols in libLLVM.so by about
25%. This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so
One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.
Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278
Reviewers: chandlerc, beanz, mgorny, rnk, hans
Reviewed By: rnk, hans
Subscribers: merge_guards_bot, luismarques, smeenai, ldionne, lenary, s.egerton, pzheng, sameer.abuasal, MaskRay, wuzish, echristo, Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D54439
Summary:
This patch fixes pr23772 [ARM] r226200 can emit illegal thumb2 instruction: "sub sp, r12, #80".
The violation was that SUB and ADD (reg, immediate) instructions can only write to SP if the source register is also SP. So the above instructions was unpredictable.
To enforce that the instruction t2(ADD|SUB)ri does not write to SP we now enforce the destination register to be rGPR (That exclude PC and SP).
Different than the ARM specification, that defines one instruction that can read from SP, and one that can't, here we inserted one that can't write to SP, and other that can only write to SP as to reuse most of the hard-coded size optimizations.
When performing this change, it uncovered that emitting Thumb2 Reg plus Immediate could not emit all variants of ADD SP, SP #imm instructions before so it was refactored to be able to. (see test/CodeGen/Thumb2/mve-stacksplot.mir where we use a subw sp, sp, Imm12 variant )
It also uncovered a disassembly issue of adr.w instructions, that were only written as SUBW instructions (see llvm/test/MC/Disassembler/ARM/thumb2.txt).
Reviewers: eli.friedman, dmgreen, carwil, olista01, efriedma, andreadb
Reviewed By: efriedma
Subscribers: gbedwell, john.brawn, efriedma, ostannard, kristof.beyls, hiraditya, dmgreen, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70680
The argument is llvm::null() everywhere except llvm::errs() in
llvm-objdump in -DLLVM_ENABLE_ASSERTIONS=On builds. It is used by no
target but X86 in -DLLVM_ENABLE_ASSERTIONS=On builds.
If we ever have the needs to add verbose log to disassemblers, we can
record log with a member function, instead of passing it around as an
argument.
Summary:
This patch fixes pr23772 [ARM] r226200 can emit illegal thumb2 instruction: "sub sp, r12, #80".
The violation was that SUB and ADD (reg, immediate) instructions can only write to SP if the source register is also SP. So the above instructions was unpredictable.
To enforce that the instruction t2(ADD|SUB)ri does not write to SP we now enforce the destination register to be rGPR (That exclude PC and SP).
Different than the ARM specification, that defines one instruction that can read from SP, and one that can't, here we inserted one that can't write to SP, and other that can only write to SP as to reuse most of the hard-coded size optimizations.
When performing this change, it uncovered that emitting Thumb2 Reg plus Immediate could not emit all variants of ADD SP, SP #imm instructions before so it was refactored to be able to. (see test/CodeGen/Thumb2/mve-stacksplot.mir where we use a subw sp, sp, Imm12 variant )
It also uncovered a disassembly issue of adr.w instructions, that were only written as SUBW instructions (see llvm/test/MC/Disassembler/ARM/thumb2.txt).
Reviewers: eli.friedman, dmgreen, carwil, olista01, efriedma
Reviewed By: efriedma
Subscribers: john.brawn, efriedma, ostannard, kristof.beyls, hiraditya, dmgreen, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70680
Summary:
Most libraries are defined in the lib/ directory but there are also a
few libraries defined in tools/ e.g. libLLVM, libLTO. I'm defining
"Component Libraries" as libraries defined in lib/ that may be included in
libLLVM.so. Explicitly marking the libraries in lib/ as component
libraries allows us to remove some fragile checks that attempt to
differentiate between lib/ libraries and tools/ libraires:
1. In tools/llvm-shlib, because
llvm_map_components_to_libnames(LIB_NAMES "all") returned a list of
all libraries defined in the whole project, there was custom code
needed to filter out libraries defined in tools/, none of which should
be included in libLLVM.so. This code assumed that any library
defined as static was from lib/ and everything else should be
excluded.
With this change, llvm_map_components_to_libnames(LIB_NAMES, "all")
only returns libraries that have been added to the LLVM_COMPONENT_LIBS
global cmake property, so this custom filtering logic can be removed.
Doing this also fixes the build with BUILD_SHARED_LIBS=ON
and LLVM_BUILD_LLVM_DYLIB=ON.
2. There was some code in llvm_add_library that assumed that
libraries defined in lib/ would not have LLVM_LINK_COMPONENTS or
ARG_LINK_COMPONENTS set. This is only true because libraries
defined lib lib/ use LLVMBuild.txt and don't set these values.
This code has been fixed now to check if the library has been
explicitly marked as a component library, which should now make it
easier to remove LLVMBuild at some point in the future.
I have tested this patch on Windows, MacOS and Linux with release builds
and the following combinations of CMake options:
- "" (No options)
- -DLLVM_BUILD_LLVM_DYLIB=ON
- -DLLVM_LINK_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_BUILD_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_LINK_LLVM_DYLIB=ON
Reviewers: beanz, smeenai, compnerd, phosek
Reviewed By: beanz
Subscribers: wuzish, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, mgorny, mehdi_amini, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, dang, Jim, lenary, s.egerton, pzheng, sameer.abuasal, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70179
Specify the Unpredictable bits, and return softfails when appropriate.
Patch by Mark Murray!
Differential revision: https://reviews.llvm.org/D66939
llvm-svn: 371374
This adds the patterns required to transform xor P0, -1 to a VPNOT. The
instruction operands have to change a little for this, adding an in and an out
VCCR reg and using a custom DecodeMVEVPNOT for the decode.
Differential Revision: https://reviews.llvm.org/D65133
llvm-svn: 367192
Summary:
According to the new Armv8-M specification
https://static.docs.arm.com/ddi0553/bh/DDI0553B_h_armv8m_arm.pdf the
instructions SQRSHRL and UQRSHLL now have an additional immediate
operand <saturate>. The new assembly syntax is:
SQRSHRL<c> RdaLo, RdaHi, #<saturate>, Rm
UQRSHLL<c> RdaLo, RdaHi, #<saturate>, Rm
where <saturate> can be either 64 (the existing behavior) or 48, in
that case the result is saturated to 48 bits.
The new operand is encoded as follows:
#64 Encoded as sat = 0
#48 Encoded as sat = 1
sat is bit 7 of the instruction bit pattern.
This patch adds a new assembler operand class MveSaturateOperand which
implements parsing and encoding. Decoding is implemented in
DecodeMVEOverlappingLongShift.
Reviewers: ostannard, simon_tatham, t.p.northover, samparker, dmgreen, SjoerdMeijer
Reviewed By: simon_tatham
Subscribers: javed.absar, kristof.beyls, hiraditya, pbarrio, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64810
llvm-svn: 366555
The BF and WLS/WLSTP instructions have various branch-offset fields
occupying different positions and lengths in the instruction encoding,
and all of them were decoded at disassembly time by the function
DecodeBFLabelOffset() which returned SoftFail if the offset was zero.
In fact, it's perfectly fine and not even a SoftFail for most of those
offset fields to be zero. The only one that can't be zero is the 4-bit
field labelled `boff` in the architecture spec, occupying bits {26-23}
of the BF instruction family. If that one is zero, the encoding
overlaps other instructions (WLS, DLS, LETP, VCTP), so it ought to be
a full Fail.
Fixed by adding an extra template parameter to DecodeBFLabelOffset
which controls whether a zero offset is accepted or rejected. Adjusted
existing tests (only in error messages for bad disassemblies); added
extra tests to demonstrate zero offsets being accepted in all the
right places, and a few demonstrating rejection of zero `boff`.
Reviewers: DavidSpickett, ostannard
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63864
llvm-svn: 364533
Different versions of the Arm architecture disallow the use of generic
coprocessor instructions like MCR and CDP on different sets of
coprocessors. This commit centralises the check of the coprocessor
number so that it's consistent between assembly and disassembly, and
also updates it for the new restrictions in Arm v8.1-M.
New tests added that check all the coprocessor numbers; old tests
updated, where they used a number that's now become illegal in the
context in question.
Reviewers: DavidSpickett, ostannard
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63863
llvm-svn: 364532
In the `CSEL Rd,Rm,Rn` instruction family (also including CSINC, CSINV
and CSNEG), the architecture lists it as CONSTRAINED UNPREDICTABLE
(i.e. SoftFail) to use SP in the Rd or Rm slot, but outright illegal
to use it in the Rn slot, not least because some encodings of that
form are used by MVE instructions such as UQRSHLL.
MC was treating all three slots the same, as SoftFail. So the only
reason UQRSHLL was disassembled correctly at all was because the MVE
decode table is separate from the Thumb2 one and takes priority; if
you turned off MVE, then encodings such as `[0x5f,0xea,0x0d,0x83]`
would disassemble as spurious CSELs.
Fixed by inventing another version of the `GPRwithZR` register class,
which disallows SP completely instead of just SoftFailing it.
Reviewers: DavidSpickett, ostannard
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63862
llvm-svn: 364531
This final batch includes the tail-predicated versions of the
low-overhead loop instructions (LETP); the VPSEL instruction to select
between two vector registers based on the predicate mask without
having to open a VPT block; and VPNOT which complements the predicate
mask in place.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62681
llvm-svn: 364292
This adds the rest of the vector memory access instructions. It
includes contiguous loads/stores, with an ordinary addressing mode
such as [r0,#offset] (plus writeback variants); gather loads and
scatter stores with a scalar base address register and a vector of
offsets from it (written [r0,q1] or similar); and gather/scatters with
a vector of base addresses (written [q0,#offset], again with
writeback). Additionally, some of the loads can widen each loaded
value into a larger vector lane, and the corresponding stores narrow
them again.
To implement these, we also have to add the addressing modes they
need. Also, in AsmParser, the `isMem` query function now has
subqueries `isGPRMem` and `isMVEMem`, according to which kind of base
register is used by a given memory access operand.
I've also had to add an extra check in `checkTargetMatchPredicate` in
the AsmParser, without which our last-minute check of `rGPR` register
operands against SP and PC was failing an assertion because Tablegen
had inserted an immediate 0 in place of one of a pair of tied register
operands. (This matches the way the corresponding check for `MCK_rGPR`
in `validateTargetOperandClass` is guarded.) Apparently the MVE load
instructions were the first to have ever triggered this assertion, but
I think only because they were the first to have a combination of the
usual Arm pre/post writeback system and the `rGPR` class in particular.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62680
llvm-svn: 364291
This adds the family of loads and stores with names like VLD20.8 and
VST42.32, which load and store parts of multiple q-registers in such a
way that executing both VLD20 and VLD21, or all four of VLD40..VLD43,
will distribute 2 or 4 vectors' worth of memory data across the lanes
of the same number of registers but in a transposed order.
In addition to the Tablegen descriptions of the instructions
themselves, this patch also adds encode and decode support for the
QQPR and QQQQPR register classes (representing the range of loaded or
stored vector registers), and tweaks to the parsing system for lists
of vector registers to make it return the right format in this case
(since, unlike NEON, MVE regards q-registers as primitive, and not
just an alias for two d-registers).
llvm-svn: 364172
These instructions let you load half a vector register at once from
two general-purpose registers, or vice versa.
The assembly syntax for these instructions mentions the vector
register name twice. For the move _into_ a vector register, the MC
operand list also has to mention the register name twice (once as the
output, and once as an input to represent where the unchanged half of
the output register comes from). So we can conveniently assign one of
the two asm operands to be the output $Qd, and the other $QdSrc, which
avoids confusing the auto-generated AsmMatcher too much. For the move
_from_ a vector register, there's no way to get round the fact that
both instances of that register name have to be inputs, so we need a
custom AsmMatchConverter to avoid generating two separate output MC
operands. (And even that wouldn't have worked if it hadn't been for
D60695.)
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62679
llvm-svn: 364041
This adds the `MVE_qDest_rSrc` superclass and all its instances, plus
a few other instructions that also take a scalar input register or two.
I've also belatedly added custom diagnostic messages to the operand
classes for odd- and even-numbered GPRs, which required matching
changes in two of the existing MVE assembly test files.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62678
llvm-svn: 364040
Summary:
This adds the `MVE_qDest_qSrc` superclass and all instructions that
inherit from it. It's not the complete class of _everything_ with a
q-register as both destination and source; it's a subset of them that
all have similar encodings (but it would have been hopelessly unwieldy
to call it anything like MVE_111x11100).
This category includes add/sub with carry; long multiplies; halving
multiplies; multiply and accumulate, and some more complex
instructions.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62677
llvm-svn: 364037
Summary:
These take a pair of vector register to compare, and a comparison type
(written in the form of an Arm condition suffix); they output a vector
of booleans in the VPR register, where predication can conveniently
use them.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62676
llvm-svn: 364027
This includes integer arithmetic of various kinds (add/sub/multiply,
saturating and not), and the immediate forms of VMOV and VMVN that
load an immediate into all lanes of a vector.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62674
llvm-svn: 363936
The ARMDisassembler changes allow changing between ARM and Thumb mode
based on the MCSubtargetInfo, rather than the Target, which simplifies
the other changes a bit.
I'm not really happy with adding more target-specific logic to
tools/llvm-objdump/, but there isn't any easy way around it: the logic
in question specifically applies to disassembling an object file, and
that code simply isn't located in lib/Target, at least at the moment.
Differential Revision: https://reviews.llvm.org/D60927
llvm-svn: 363903
This includes all the obvious bitwise operations (AND, OR, BIC, ORN,
MVN) in register-to-register forms, and the immediate forms of
AND/OR/BIC/ORN; byte-order reverse instructions; and the VMOVs that
access a single lane of a vector.
Some of those VMOVs (specifically, the ones that access a 32-bit lane)
share an encoding with existing instructions that were disassembled as
accessing half of a d-register (e.g. `vmov.32 r0, d1[0]`), but in
8.1-M they're now written as accessing a quarter of a q-register (e.g.
`vmov.32 r0, q0[2]`). The older syntax is still accepted by the
assembler.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62673
llvm-svn: 363838
Summary:
Their names began with a mishmash of `MVE_`, `t2` and no prefix at
all. Now they all start with `MVE_`, which seems like a reasonable
choice on the grounds that (a) NEON is the thing they're most at risk
of being confused with, and (b) MVE implies Thumb-2, so a prefix
indicating MVE is strictly more specific than one indicating Thumb-2.
Reviewers: ostannard, SjoerdMeijer, dmgreen
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63492
llvm-svn: 363690
This commit prepares the way to start adding the main collection of
MVE instructions, which operate on the 128-bit vector registers.
The most obvious thing that's needed, and the simplest, is to add the
MQPR register class, which is like the existing QPR except that it has
fewer registers in it.
The more complicated part: MVE defines a system of vector predication,
in which instructions operating on 128-bit vector registers can be
constrained to operate on only a subset of the lanes, using a system
of prefix instructions similar to the existing Thumb IT, in that you
have one prefix instruction which designates up to 4 following
instructions as subject to predication, and within that sequence, the
predicate can be inverted by means of T/E suffixes ('Then' / 'Else').
To support instructions of this type, we've added two new Tablegen
classes `vpred_n` and `vpred_r` for standard clusters of MC operands
to add to a predicated instruction. Both include a flag indicating how
the instruction is predicated at all (options are T, E and 'not
predicated'), and an input register field for the register controlling
the set of active lanes. They differ from each other in that `vpred_r`
also includes an input operand for the previous value of the output
register, for instructions that leave inactive lanes unchanged.
`vpred_n` lacks that extra operand; it will be used for instructions
that don't preserve inactive lanes in their output register (either
because inactive lanes are zeroed, as the MVE load instructions do, or
because the output register isn't a vector at all).
This commit also adds the family of prefix instructions themselves
(VPT / VPST), and all the machinery needed to work with them in
assembly and disassembly (e.g. generating the 't' and 'e' mnemonic
suffixes on disassembled instructions within a predicated block)
I've added a couple of demo instructions that derive from the new
Tablegen base classes and use those two operand clusters. The bulk of
the vector instructions will come in followup commits small enough to
be manageable. (One exception is that I've added the full version of
`isMnemonicVPTPredicable` in the AsmParser, because it seemed
pointless to carefully split it up.)
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62669
llvm-svn: 363258
During assembly, the mask operand to an IT instruction (storing the
sequence of T/E for 'Then' and 'Else') is parsed out of the mnemonic
into a representation that encodes 'Then' and 'Else' in the same way
regardless of the condition code. At some point during encoding it has
to be converted into the instruction encoding used in the
architecture, in which the mask encodes a sequence of replacement
low-order bits for the condition code, so that which bit value means
'then' and which 'else' depends on whether the original condition code
had its low bit set.
Previously, that transformation was done by processInstruction(), half
way through assembly. So an MCOperand storing an IT mask would
sometimes store it in one format, and sometimes in the other,
depending on where in the assembly pipeline you were. You can see this
in diagnostics from `llvm-mc -debug -triple=thumbv8a -show-inst`, for
example: if you give it an instruction such as `itete eq`, you'd see
an `<MCOperand Imm:5>` in a diagnostic become `<MCOperand Imm:11>` in
the final output.
Having the same data structure store values with time-dependent
semantics is confusing already, and it will get more confusing when we
introduce the MVE VPT instruction which reuses the Then/Else bitmask
idea in a different context. So I'm refactoring: now, all `ARMOperand`
and `MCOperand` representations of an IT mask work exactly the same
way, namely, 0 means 'Then' and 1 means 'Else', regardless of what
original predicate is being referred to. The architectural encoding of
IT that depends on the original condition is now constructed at the
point when we turn the `MCOperand` into the final instruction bit
pattern, and decoded similarly in the disassembler.
The previous condition-independent parse-time format used 0 for Else
and 1 for Then. I've taken the opportunity to flip the sense of it
while I'm changing all of this anyway, because it seems to me more
natural to use 0 for 'leave the starting condition unchanged' and 1
for 'invert it', as if those bits were an XOR mask.
Reviewers: ostannard
Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63219
llvm-svn: 363244
This introduces a new decoding table for MVE instructions, and starts
by adding the family of scalar shift instructions that are part of the
MVE architecture extension: saturating shifts within a single GPR, and
long shifts across a pair of GPRs (both saturating and normal).
Some of these shift instructions have only 3-bit register fields in
the encoding, with the low bit fixed. So they can only address an odd
or even numbered GPR (depending on the operand), and therefore I add
two new register classes, GPREven and GPROdd.
Differential Revision: https://reviews.llvm.org/D62668
Change-Id: Iad95d5f83d26aef70c674027a184a6b1e0098d33
llvm-svn: 363051
James Y Knight