Fixes#82557. APX specification states that the high bits found in REX2
used to encode GPRs can also be used to encode control and debug
registers, although all of them will #UD. Therefore, when disassembling
we reject attempts to create control or debug registers with a value of
16 or more.
See page 22 of the
[specification](https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html):
> Note that the R, X and B register identifiers can also address non-GPR
register types, such as vector registers, control registers and debug
registers. When any of them does, the highest-order bits REX2.R4,
REX2.X4 or REX2.B4 are generally ignored, except when the register being
addressed is a control or debug register. [...] The exception is that
REX2.R4 and REX2.R3 [*sic*] are not ignored when the R register
identifier addresses a control or debug register. Furthermore, if any
attempt is made to access a non-existent control register (CR*) or debug
register (DR*) using the REX2 prefix and one of the following
instructions:
“MOV CR*, r64”, “MOV r64, CR*”, “MOV DR*, r64”, “MOV r64, DR*”. #UD is
raised.
The invalid encodings are 64-bit only because `0xd5` is a valid
instruction in 32-bit mode.
PUSH2 and POP2 are two new instructions for (respectively)
pushing/popping 2 GPRs at a time to/from
the stack. The opcodes of PUSH2 and POP2 are those of “PUSH r/m” and
“POP r/m” from legacy map 0, but we
require ModRM.Mod = 3 in order to disallow memory operand.
The 1-bit Push-Pop Acceleration hint described in #73092 applies to
PUSH2/POP2 too, then we have PUSH2P/POP2P.
For AT&T syntax, PUSH2[P] pushes the registers from right to left onto
the stack. POP2[P] pops the stack to registers from right to left. Intel
syntax has the opposite order - from left to right.
The assembly syntax is aligned with GCC & binutils
https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637718.html
A PUSH and its corresponding POP may be marked with a 1-bit Push-Pop Acceleration (PPX)
hint to indicate that the POP reads the value written by the PUSH from the stack. The PPX hint
is encoded by setting REX2.W = 1 and is applicable only to PUSH with opcode 0x50+rd and POP
with opcode 0x58+rd in the legacy space. It is not applicable to any other variants of PUSH and POP.
JMPABS is a 64-bit only ISA extension, and acts as a near-direct branch
with an absolute target. The 64-bit immediate operand is treated an as
absolute effective address, which is subject to canonicality checks. It
is in legacy map 0 and requires REX2 prefix with `REX2.M0=0` and
`REX2.W=0`. All other REX2 payload bits are ignored.
blog: https://kanrobert.github.io/rfc/All-about-APX-JMPABS/
This patch
1. Extends `ExplicitVEXPrefix` to `ExplicitOpPrefix` for instrcutions
requires explicit `REX2` or `EVEX`
2. Adds `ATTR_REX2` and `IC_64BIT_REX2` to put `JMPABS` , `MOV EAX,
moffs32` in different tables to avoid opcode conflict
NOTE:
1. `ExplicitREX2Prefix` can be reused by the following PUSHP/POPP
instructions.
2. `ExplicitEVEXPrefix` will be used by the instructions promoted to
EVEX space for EGPR.
https://github.com/llvm/llvm-project/pull/70958 adds registers R16-R31
(EGPR), this patch
1. Supports decoding of EGPR for instruction w/ REX2 prefix
2. Supports decoding of EGPR for instruction w/ EVEX prefix
For simplicity's sake, we
1. Simulate the REX prefix w/ the 1st payload of REX2
2. Simulate the REX2 prefix w/ the 2nd and 3rd payloads of EVEX
RFC:
https://discourse.llvm.org/t/rfc-design-for-apx-feature-egpr-and-ndd-support/73031/4
Explanations for some changes:
1. invalid-EVEX-R2.txt is deleted b/c `0x62 0xe1 0xff 0x08 0x79 0xc0` is
valid and decoded to `vcvtsd2usi %xmm0, %r16` now.
2. One line in x86-64-err.txt is removed b/c APX relaxes the limitation
of the 1st and 2nd payloads of EVEX prefix, so the error message changes
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an
enum. This patch replaces support::{big,little,native} with
llvm::endianness::{big,little,native}.
On 64-bit X86, 0x66 operand-size override prefix will change the size of
the instruction operand, e.g. from 32 bits to 16 bits, but it will not
modify the size of the displacement operand used for memory addressing,
which will always be 32 bits.
Reviewed By: skan, rafauler
Differential Revision: https://reviews.llvm.org/D126726
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
-Rename Mode*Bit to Is*Bit to match X86Subtarget.
-Rename FeatureLAHFSAHF to FeatureLAFHSAFH64 to match X86Subtarget.
-Use consistent capitalization
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D121975
Fix a number of issues with MCSymbolizer::tryAddingSymbolicOperand()
in X86Disassembler:
* Pass instruction size instead of immediate size.
* Correctly adjust the value of PC-relative operands.
* Set operand offset to zero when the operand is specified
implicitly.
Reviewed By: Amir, skan
Differential Revision: https://reviews.llvm.org/D121065
GCC 9.1 removed Intel MPX support. Linux kernel removed MPX in 2019.
glibc 2.35 will remove MPX.
Our support is limited: we support assembling of bndmov but not bnd.
Just remove it.
Reviewed By: pengfei, skan
Differential Revision: https://reviews.llvm.org/D111517
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 maskmovdqu instruction is an odd one: it has a 32-bit and a 64-bit
variant, the former using EDI, the latter RDI, but the use of the
register is implicit. In 64-bit mode, a 0x67 prefix can be used to get
the version using EDI, but there is no way to express this in
assembly in a single instruction, the only way is with an explicit
addr32.
This change adds support for the instruction. When generating assembly
text, that explicit addr32 will be added. When not generating assembly
text, it will be kept as a single instruction and will be emitted with
that 0x67 prefix. When parsing assembly text, it will be re-parsed as
ADDR32 followed by MASKMOVDQU64, which still results in the correct
bytes when converted to machine code.
The same applies to vmaskmovdqu as well.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D103427
For x86-64 the REX.w prefix takes precedence over any other size
override (i.e. 0x66). Therefore, for x86-64 when REX.w is present set
'hasOpSize' to false to ensure that any size override is ignored.
Fixes PR48901.
Differential Revision: https://reviews.llvm.org/D95682
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
readPrefixes() assumes insn->bytes is non-empty. The code path is not
exercised in llvm-mc because llvm-mc does not feed empty input to
MCDisassembler::getInstruction().
This bug is uncovered by a5994c789a2982a770254ae1607b5b4cb641f73c.
An empty string did not crash before because the deleted regionReader()
allowed UINT64_C(-1) as insn->readerCursor.
Bytes.size() <= Address -> R->Base
0 <= UINT64_C(-1) - UINT32_C(-1)
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.
llvm-objdump -d on clang is decreased from 7.8s to 7.4s.
The improvement is likely due to the elimination of logger setup and
dbgprintf(), which has a large overhead.
This reverts r362990 (git commit 374571301dc8e9bc9fdd1d70f86015de198673bd)
This was causing linker warnings on Darwin:
ld: warning: direct access in function 'llvm::initializeEvexToVexInstPassPass(llvm::PassRegistry&)'
from file '../../lib/libLLVMX86CodeGen.a(X86EvexToVex.cpp.o)' to global weak symbol
'void std::__1::__call_once_proxy<std::__1::tuple<void* (&)(llvm::PassRegistry&),
std::__1::reference_wrapper<llvm::PassRegistry>&&> >(void*)' from file '../../lib/libLLVMCore.a(Verifier.cpp.o)'
means the weak symbol cannot be overridden at runtime. This was likely caused by different translation
units being compiled with different visibility settings.
llvm-svn: 363028
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: Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, 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
llvm-svn: 362990
Move the declarations of getThe<Name>Target() functions into a new header in
TargetInfo and make users of these functions include this new header.
This fixes a layering problem.
llvm-svn: 360736
Summary:
This avoids needing an isel pattern for each condition code. And it removes translation switches for converting between Jcc instructions and condition codes.
Now the printer, encoder and disassembler take care of converting the immediate. We use InstAliases to handle the assembly matching. But we print using the asm string in the instruction definition. The instruction itself is marked IsCodeGenOnly=1 to hide it from the assembly parser.
Reviewers: spatel, lebedev.ri, courbet, gchatelet, RKSimon
Reviewed By: RKSimon
Subscribers: MatzeB, qcolombet, eraman, hiraditya, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60228
llvm-svn: 357802
Summary:
Reorder the condition code enum to match their encodings. Move it to MC layer so it can be used by the scheduler models.
This avoids needing an isel pattern for each condition code. And it removes
translation switches for converting between CMOV instructions and condition
codes.
Now the printer, encoder and disassembler take care of converting the immediate.
We use InstAliases to handle the assembly matching. But we print using the
asm string in the instruction definition. The instruction itself is marked
IsCodeGenOnly=1 to hide it from the assembly parser.
This does complicate the scheduler models a little since we can't assign the
A and BE instructions to a separate class now.
I plan to make similar changes for SETcc and Jcc.
Reviewers: RKSimon, spatel, lebedev.ri, andreadb, courbet
Reviewed By: RKSimon
Subscribers: gchatelet, hiraditya, kristina, lebedev.ri, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60041
llvm-svn: 357800
Previously we had a regular form of the instruction used when the immediate was 0-7. And _alt form that allowed the full 8 bit immediate. Codegen would always use the 0-7 form since the immediate was always checked to be in range. Assembly parsing would use the 0-7 form when a mnemonic like vpcomtrueb was used. If the immediate was specified directly the _alt form was used. The disassembler would prefer to use the 0-7 form instruction when the immediate was in range and the _alt form otherwise. This way disassembly would print the most readable form when possible.
The assembly parsing for things like vpcomtrueb relied on splitting the mnemonic into 3 pieces. A "vpcom" prefix, an immediate representing the "true", and a suffix of "b". The tablegenerated printing code would similarly print a "vpcom" prefix, decode the immediate into a string, and then print "b".
The _alt form on the other hand parsed and printed like any other instruction with no specialness.
With this patch we drop to one form and solve the disassembly printing issue by doing custom printing when the immediate is 0-7. The parsing code has been tweaked to turn "vpcomtrueb" into "vpcomb" and then the immediate for the "true" is inserted either before or after the other operands depending on at&t or intel syntax.
I'd rather not do the custom printing, but I tried using an InstAlias for each possible mnemonic for all 8 immediates for all 16 combinations of element size, signedness, and memory/register. The code emitted into printAliasInstr ended up checking the number of operands, the register class of each operand, and the immediate for all 256 aliases. This was repeated for both the at&t and intel printer. Despite a lot of common checks between all of the aliases, when compiled with clang at least this commonality was not well optimized. Nor do all the checks seem necessary. Since I want to do a similar thing for vcmpps/pd/ss/sd which have 32 immediate values and 3 encoding flavors, 3 register sizes, etc. This didn't seem to scale well for clang binary size. So custom printing seemed a better trade off.
I also considered just using the InstAlias for the matching and not the printing. But that seemed like it would add a lot of extra rows to the matcher table. Especially given that the 32 immediates for vpcmpps have 46 strings associated with them.
Differential Revision: https://reviews.llvm.org/D59398
llvm-svn: 356343
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
Summary:
If LOCK prefix is not the first prefix in an instruction, LLVM
disassembler silently drops the prefix.
The fix is to select a proper instruction with a builtin LOCK prefix if
one exists.
Reviewers: craig.topper
Reviewed By: craig.topper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49001
llvm-svn: 336400
I've check the disassembler tables and this shouldn't be reachable. Which is good since if it was reachable there should have been a 'return' after the addOperand line.
llvm-svn: 336066
The %eiz/%riz are dummy registers that force the encoder to emit a SIB byte when it normally wouldn't. By emitting them in the disassembly output we ensure that assembling the disassembler output would also produce a SIB byte.
This should match the behavior of objdump from binutils.
llvm-svn: 335768
