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This patch adds support to the GNU assembler for an alternative
assembly syntax used in BPF. This syntax is C-like and very
unconventional for an assembly language, but it is generated by
clang/llvm and is also used in inline asm templates in kernel code, so
we ought to support it.
After this patch, the assembler is able to parse instructions in both
supported syntax: the normal assembly-like syntax and the pseudo-C
syntax. Instruction formats can be mixed in the source program: the
assembler recognizes the right syntax to use.
gas/ChangeLog:
2023-04-20 Guillermo E. Martinez <guillermo.e.martinez@oracle.com>
PR gas/29728
* config/tc-bpf.h (TC_EQUAL_IN_INSN): Define.
* config/tc-bpf.c (LEX_IS_SYMBOL_COMPONENT): Define.
(LEX_IS_WHITESPACE): Likewise.
(LEX_IS_NEWLINE): Likewise.
(LEX_IS_ARITHM_OP): Likewise.
(LEX_IS_STAR): Likewise.
(LEX_IS_CLSE_BR): Likewise.
(LEX_IS_OPEN_BR): Likewise.
(LEX_IS_EQUAL): Likewise.
(LEX_IS_EXCLA): Likewise.
(ST_EOI): Likewise.
(MAX_TOKEN_SZ): Likewise.
(init_pseudoc_lex): New function.
(md_begin): Call init_pseudoc_lex.
(valid_expr): New function.
(build_bpf_non_generic_load): Likewise.
(build_bpf_atomic_insn): Likewise.
(build_bpf_jmp_insn): Likewise.
(build_bpf_arithm_insn): Likewise.
(build_bpf_endianness): Likewise.
(build_bpf_load_store_insn): Likewise.
(look_for_reserved_word): Likewise.
(is_register): Likewise.
(is_cast): Likewise.
(get_token): Likewise.
(bpf_pseudoc_to_normal_syntax): Likewise.
(md_assemble): Try pseudo-C syntax if an instruction cannot be
parsed.
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Special casing GPR names in my_getSmallExpression() leads to a number of
inconsistencies. Generalize this by utilizing the md_parse_name() hook,
limited to when instruction operands are being parsed (really: probed).
Then both the GPR lookup there and the yet more ad hoc workaround for
PR/gas 29940 can be removed (including its extension needed for making
the compressed form JAL work again).
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With my_getSmallExpression() consistently and silently failing on
relocation operators not fitting an insn, it is no longer necessary to
hand it percent_op_itype[] "just in case" (i.e. to avoid errors when a
subsequent parsing attempt for another operand combination might
succeed). This also eliminates the latent problem of percent_op_itype[]
and percent_op_stype[] growing a non-identical set of recognized
relocation operators.
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The use of a wrong (for the insn) relocation operator (or a future one
which simply isn't recognized by older gas yet) doesn't render the (rest
of the) expression "bad". Furthermore alongside the error from
expression() in most cases the parser would emit another error then
anyway. Suppress the call to my_getExpression() in such a case,
arranging for a guaranteed subsequent error message by marking the
expression "illegal".
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Both callers check for no relocations, so there's no point parsing for
some. Have the function pass percent_op_null into
my_getSmallExpression(). Note that there's no point passing
percent_op_itype: Elsewhere, especially when processing compressed alias
insns ahead of non-alias ones, this has the effect of avoiding "bad
expression" errors when another parsing pass may follow (and succeed).
Here, however, all alternative forms of an insn type will again start
with the same O4 or O2, so avoiding errors earlier on doesn't really
help. Plus constructs with a relocation specifier (as percent_op_itype
would permit) can't be specified anyway, as the scrubber eats the
whitespace between .insn's type and the O4 or O2 expression when that
starts with % or ( - i.e. these will be seen as e.g. "i%lo(x)", and
riscv_ip() looks only for whitespace when finding the end of a mnemonic.
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The sole caller of parse_relocation() has already checked for the %
prefix, so there's no need to check for it again in the strncasecmp()
and there's also no reason to make the involved string literals longer
than necessary.
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-mfix-looongson3-llsc may add sync instructions not needed on some
asm code with lots of debug info.
PR: 30153
* gas/config/tc-mips.c(fix_loongson3_llsc): clear logistic.
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This reverts the code change done by 100f993c53a5 ("x86: Check
unbalanced braces in memory reference"), which wrongly identified
e87fb6a6d0cd ("x86/gas: support quoted address scale factor in AT&T
syntax") as the root cause of PR gas/30248. (The testcase is left in
place, no matter that it's at best marginally useful in that shape.)
The problem instead is that parse_register() alters the string handed to
it, thus breaking valid assumptions in subsequent parsing code. Since
the function's behavior is a result of get_symbol_name()'s, make a copy
of the incoming string before invoking that function.
Like for parse_real_register() follow the model of strtol() et al: input
string is const-qualified to signal that the string isn't altered, but
the returned "end" pointer is not const-qualified, requiring const to be
cast away (which generally is a bad idea, but the alternative would
again be more convoluted code).
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Follow the model of strtol() et al - input string is const-qualified to
signal that the string isn't altered, but the returned "end" pointer is
not const-qualified, requiring const to be cast away (which generally is
a bad idea, but the alternative would be more convoluted code).
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gas
* config/tc-loongarch.c (loongarch_fix_adjustable): Symbols with GOT relocatios do not fix adjustbale.
* testsuite/gas/loongarch/macro_op_large_abs.d: Regenerated.
* testsuite/gas/loongarch/macro_op_large_pc.d: Regenerated.
ld
* testsuite/ld-loongarch-elf/macro_op.d: Regenerated. -
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gas/ChangeLog:
* NEWS: Support Intel AMX-COMPLEX.
* config/tc-i386.c: Add amx_complex.
* doc/c-i386.texi: Document .amx_complex.
* testsuite/gas/i386/i386.exp: Run AMX-COMPLEX tests.
* testsuite/gas/i386/amx-complex-inval.l: New test.
* testsuite/gas/i386/amx-complex-inval.s: Ditto.
* testsuite/gas/i386/x86-64-amx-complex-bad.d: Ditto.
* testsuite/gas/i386/x86-64-amx-complex-bad.s: Ditto.
* testsuite/gas/i386/x86-64-amx-complex-intel.d: Ditto.
* testsuite/gas/i386/x86-64-amx-complex.d: Ditto.
* testsuite/gas/i386/x86-64-amx-complex.s: Ditto.
opcodes/ChangeLog:
* i386-dis.c (MOD_VEX_0F386C_X86_64_W_0): New.
(PREFIX_VEX_0F386C_X86_64_W_0_M_1_L_0): Ditto.
(X86_64_VEX_0F386C): Ditto.
(VEX_LEN_0F386C_X86_64_W_0_M_1): Ditto.
(VEX_W_0F386C_X86_64): Ditto.
(mod_table): Add MOD_VEX_0F386C_X86_64_W_0.
(prefix_table): Add PREFIX_VEX_0F386C_X86_64_W_0_M_1_L_0.
(x86_64_table): Add X86_64_VEX_0F386C.
(vex_len_table): Add VEX_LEN_0F386C_X86_64_W_0_M_1.
(vex_w_table): Add VEX_W_0F386C_X86_64.
* i386-gen.c (cpu_flag_init): Add CPU_AMX_COMPLEX_FLAGS and
CPU_ANY_AMX_COMPLEX_FLAGS.
* i386-init.h: Regenerated.
* i386-mnem.h: Ditto.
* i386-opc.h (CpuAMX_COMPLEX): New.
(i386_cpu_flags): Add cpuamx_complex.
* i386-opc.tbl: Add AMX-COMPLEX instructions.
* i386-tbl.h: Regenerated.
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tc-aarch64.c:1473:27: runtime error: left shift of 7 by 30 places
cannot be represented in type 'int'.
* config/tc-aarch64.c (parse_vector_reg_list): Avoid UB left
shift.
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This commit intends to move operands that require very special handling or
operand types that are so minor (e.g. only useful on a few instructions)
under "W". I also intend this "W" to be "temporary" operand storage until
we can find good two character (or less) operand type.
In this commit, prefetch offset operand "f" for 'Zicbop' extension is moved
to "Wif" because of its special handling (and allocating single character
"f" for this operand type seemed too much).
Current expected allocation guideline is as follows:
1. 'W'
2. The most closely related single-letter extension in lowercase
(strongly recommended but not mandatory)
3. Identify operand type
The author currently plans to allocate following three-character operand
types (for operands including instructions from unratified extensions).
1. "Wif" ('Zicbop': fetch offset)
2. "Wfv" (unratified 'Zfa': value operand from FLI.[HSDQ] instructions)
3. "Wfm" / "WfM"
'Zfh', 'F', 'D', 'Q': rounding modes "m" with special handling
solely for widening conversion instructions.
gas/ChangeLog:
* config/tc-riscv.c (validate_riscv_insn, riscv_ip): Move from
"f" to "Wif".
opcodes/ChangeLog:
* riscv-dis.c (print_insn_args): Move from "f" to "Wif".
* riscv-opc.c (riscv_opcodes): Reflect new operand type.
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Since we have no insn suffix and it's also not realistic to infer
immediate size from the size of other (typically register) operands
(like optimize_imm() does), and since we also don't have a template
telling us permitted size(s), a new syntax construct is introduced to
allow size (and signedness) specification. In the absence of such, the
size is inferred from significant bits (which obviously may yield
inconsistent results at least for effectively negative values, depending
on whether BFD64 is enabled), and only if supplied expressions can be
evaluated at parsing time. Being explicit is generally recommended to
users.
Size specification is permitted at bit granularity, but of course the
eventually emitted immediate values will be padded up to 8-, 16-, 32-,
or 64-bit fields.
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.insn isn't going to have a constraint of only a single immediate when,
in particular, RIP-relative addressing is used.
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In particular the scaling factor cannot always be determined from pre-
existing operand attributes. Introduce a new {:d<N>} vector operand
syntax extension, restricted to .insn only, to allow specifying this in
(at least) otherwise ambiguous cases.
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Deal with register and memory operands; immediate operands will follow
later, as will the handling of EVEX embedded broadcast and EVEX Disp8
scaling.
Note that because we can't really know how to encode their use, %cr8 and
up cannot be used with .insn outside of 64-bit mode. Users would need to
specify an explicit LOCK prefix in combination with %cr0 etc.
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So called "short form" encoding is specified by a trailing "+r", whereas
a possible extension opcode is specified by the usual "/<digit>". Take
these off the expression before handing it to get_absolute_expression().
Note that on targets where / starts a comment, --divide needs passing to
gas in order to make use of the extension opcode functionality.
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All encoding spaces can be used this way; there's a certain risk that
the bits presently reserved could be used for other purposes down the
road, but people using .insn are expected to know what they're doing
anyway. Plus this way there's at least _some_ way to have those bits
set.
For now this will only allow operand-less insns to be encoded this way.
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For starters this deals with only very basic constructs.
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This patch adds the RPRFM (range prefetch) instruction.
It was introduced as part of SME2, but it belongs to the
prefetch hint space and so doesn't require any specific
ISA flags.
The aarch64_rprfmop_array initialiser (deliberately) only
fills in the leading non-null elements.
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This patch adds the SVE FDOT, SDOT and UDOT instructions,
which are available when FEAT_SME2 is implemented. The patch
also reorders the existing SVE_Zm3_22_INDEX to keep the
operands numerically sorted.
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There are two instruction formats here:
- SQRSHR, SQRSHRU and UQRSHR, which operate on lists of two
or four registers.
- SQRSHRN, SQRSHRUN and UQRSHRN, which operate on lists of
four registers.
These are the first SME2 instructions to have immediate operands.
The patch makes sure that, when parsing SME2 instructions with
immediate operands, the new predicate-as-counter registers are
parsed as registers rather than as #-less immediates.
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SMLALL, SMLSLL, UMLALL and UMLSLL have the same format.
USMLALL and SUMLALL allow the same operand types as those
instructions, except that SUMLALL does not have the multi-vector
x multi-vector forms (which would be redundant with USMLALL).
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The {BF,F,S,U}MLAL and {BF,F,S,U}MLSL instructions share the same
encoding. They are the first instance of a ZA (as opposed to ZA tile)
operand having a range of offsets. As with ZA tiles, the expected
range size is encoded in the operand-specific data field.
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Add support for the SME2 ADD. SUB, FADD and FSUB instructions.
SUB and FSUB have the same form as ADD and FADD, except that
ADD also has a 2-operand accumulating form.
The 64-bit ADD/SUB instructions require FEAT_SME_I16I64 and the
64-bit FADD/FSUB instructions require FEAT_SME_F64F64.
These are the first instructions to have tied register list
operands, as opposed to tied single registers.
The parse_operands change prevents unsuffixed Z registers (width==-1)
from being treated as though they had an Advanced SIMD-style suffix
(.4s etc.). It means that:
Error: expected element type rather than vector type at operand 2 -- `add za\.s\[w8,0\],{z0-z1}'
becomes:
Error: missing type suffix at operand 2 -- `add za\.s\[w8,0\],{z0-z1}'
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SME2 adds lookup table instructions for quantisation. They use
a new lookup table register called ZT0.
LUTI2 takes an unsuffixed SVE vector index of the form Zn[<imm>],
which is the first time that this syntax has been used.
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Implementation-wise, the main things to note here are:
- the WHILE* instructions have forms that return a pair of predicate
registers. This is the first time that we've had lists of predicate
registers, and they wrap around after register 15 rather than after
register 31.
- the predicate-as-counter WHILE* instructions have a fourth operand
that specifies the vector length. We can treat this as an enumeration,
except that immediate values aren't allowed.
- PEXT takes an unsuffixed predicate index of the form PN<n>[<imm>].
This is the first instance of a vector/predicate index having
no suffix.
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SME2 adds LD1 and ST1 variants for lists of 2 and 4 registers.
The registers can be consecutive or strided. In the strided case,
2-register lists have a stride of 8, starting at register x0xxx.
4-register lists have a stride of 4, starting at register x00xx.
The instructions are predicated on a predicate-as-counter register in
the range pn8-pn15. Although we already had register fields with upper
bounds of 7 and 15, this is the first plain register operand to have a
nonzero lower bound. The patch uses the operand-specific data field
to record the minimum value, rather than having separate inserters
and extractors for each lower bound. This in turn required adding
an extra bit to the field.
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SME2 defines new MOVA instructions for moving multiple registers
to and from ZA. As with SME, the instructions are also available
through MOV aliases.
One notable feature of these instructions (and many other SME2
instructions) is that some register lists must start at a multiple
of the list's size. The patch uses the general error "start register
out of range" when this constraint isn't met, rather than an error
specifically about multiples. This ensures that the error is
consistent between these simple consecutive lists and later
strided lists, for which the requirements aren't a simple multiple.
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SME2 adds a new format for the existing SVE predicate registers:
predicates as counters rather than predicates as masks. In assembly
code, operands that interpret predicates as counters are written
pn<N> rather than p<N>.
This patch adds support for these registers and extends some
existing instructions to support them. Since the new forms
are just a programmer convenience, there's no need to make them
more restrictive than the earlier predicate-as-mask forms.
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Some SME2 instructions operate on a range of consecutive ZA vectors.
This is indicated by syntax such as:
za[<Wv>, <imml>:<immh>]
Like with the earlier vgx2 and vgx4 support, we get better error
messages if the parser allows all ZA indices to have a range.
We can then reject invalid cases during constraint checking.
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Many SME2 instructions operate on groups of 2 or 4 ZA vectors.
This is indicated by adding a "vgx2" or "vgx4" group size to the
ZA index. The group size is optional in assembly but preferred
for disassembly.
There is not a binary distinction between mnemonics that have
group sizes and mnemonics that don't, nor between mnemonics that
take vgx2 and mnemonics that take vgx4. We therefore get better
error messages if we allow any ZA index to have a group size
during parsing, and wait until constraint checking to reject
invalid sizes.
A quirk of the way errors are reported means that if an instruction
is wrong both in its qualifiers and its use of a group size, we'll
print suggested alternative instructions that also have an incorrect
group size. But that's a general property that also applies to
things like out-of-range immediates. It's also not obviously the
wrong thing to do. We need to be relatively confident that we're
looking at the right opcode before reporting detailed operand-specific
errors, so doing qualifier checking first seems resonable.
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SME2 adds various new fields that are similar to
AARCH64_OPND_SME_ZA_array, but are distinguished by the size of
their offset fields. This patch adds _off4 to the name of the
field that we already have.
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This patch adds bare-bones support for +sme2. Later patches
fill in the rest.
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Until now, binutils has supported register ranges such
as { v0.4s - v3.4s } as an unofficial shorthand for
{ v0.4s, v1.4s, v2.4s, v3.4s }. The SME2 ISA embraces this form
and makes it the preferred disassembly. It also embraces wrapped
lists such as { z31.s - z2.s }, which is something that binutils
didn't previously allow.
The range form was already binutils's preferred disassembly for 3- and
4-register lists. This patch prefers it for 2-register lists too.
The patch also adds support for wrap-around.
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SME2 has instructions that accept strided register lists,
such as { z0.s, z4.s, z8.s, z12.s }. The purpose of this
patch is to extend binutils to support such lists.
The parsing code already had (unused) support for strides of 2.
The idea here is instead to accept all strides during parsing
and reject invalid strides during constraint checking.
The SME2 instructions that accept strided operands also have
non-strided forms. The errors about invalid strides therefore
take a bitmask of acceptable strides, which allows multiple
possibilities to be summed up in a single message.
I've tried to update all code that handles register lists.
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In GAS, the vector and predicate registers are identified by
REG_TYPE_VN, REG_TYPE_ZN and REG_TYPE_PN. This "N" is obviously
a placeholder for the register number. However, we don't use that
convention for integer and FP registers, and (more importantly)
SME2 adds "predicate-as-counter" registers that are denoted PN.
This patch therefore drops the "N" suffix from the existing
registers. The main hitch is that Z was also used for the
zero register in things like R_Z, but using ZR seems more
consistent with the SP-based names.
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Quite a lot of SME2 instructions have an opcode bit that selects
between 32-bit and 64-bit forms of an instruction, with the 32-bit
forms being part of base SME2 and with the 64-bit forms being part
of an optional extension. It's nevertheless useful to have a single
opcode entry for both forms since (a) that matches the ISA definition
and (b) it tends to improve error reporting.
This patch therefore adds a libopcodes function called
aarch64_cpu_supports_inst_p that tests whether the target
supports a particular instruction. In future it will depend
on internal libopcodes routines.
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There are three main kinds of error reported during parsing,
in increasing order of priority:
- AARCH64_OPDE_RECOVERABLE (register seen instead of immediate)
- AARCH64_OPDE_SYNTAX_ERROR
- AARCH64_OPDE_FATAL_SYNTAX_ERROR
This priority makes sense when comparing errors reported against the
same operand. But if we get to operand 3 (say) and see a register
instead of an immediate, that's likely to be a better match than
something that fails with a syntax error at operand 1.
The idea of this patch is to prioritise parsing-related errors
based on operand index first, then by error code. Post-parsing
errors still win over parsing errors, and their relative priorities
don't change.
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If an instruction has invalid qualifiers, GAS would report the
error against the final opcode entry that got to the qualifier-
checking stage. It seems better to report the error against
the opcode entry that had the closest match, just like we
pick the closest match within an opcode entry for the
"did you mean this?" message.
This patch adds the number of invalid operands as an
argument to AARCH64_OPDE_INVALID_VARIANT and then picks the
AARCH64_OPDE_INVALID_VARIANT with the lowest argument.
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The error for invalid register lists had the form:
invalid number of registers in the list; N registers are expected at operand M -- `insn'
This seems a bit verbose. Also, the "bracketing" is really:
(invalid number of registers in the list; N registers are expected) at operand M
but the semicolon works against that.
This patch goes for slightly shorter messages, setting a template
that later patches can use for more complex cases.
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AARCH64_OPDE_REG_LIST took a single operand that specified the
expected number of registers. However, there are quite a few
SME2 instructions that have both 2-register forms and (separate)
4-register forms. If the user tries to use a 3-register list,
it isn't obvious which opcode entry they meant. Saying that we
expect 2 registers and saying that we expect 4 registers would
both be wrong.
This patch therefore switches the operand to a bitfield. If a
AARCH64_OPDE_REG_LIST is reported against multiple opcode entries,
the patch ORs up the expected lengths.
This has no user-visible effect yet. A later patch adds more error
strings, alongside tests that use them.
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libopcodes currently reports out-of-range registers as a general
AARCH64_OPDE_OTHER_ERROR. However, this means that each register
range needs its own hard-coded string, which is a bit cumbersome
if the range is determined programmatically. This patch therefore
adds a dedicated error type for out-of-range errors.
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SME2 has many instructions that take a list of SVE registers.
There are often multiple forms, with different forms taking
different numbers of registers.
This means that if, after a successful parse and qualifier match,
we find that the number of registers does not match the opcode entry,
the associated error should have a lower priority/severity than other
errors reported at the same stage. For example, if there are 2-register
and 4-register forms of an instruction, and if the assembly code uses
the 2-register form with an out-of-range value, the out-of-range value
error against the 2-register instruction should have a higher priority
than the "wrong number of registers" error against the 4-register
instruction.
This is tested by the main SME2 patches, but seemed worth splitting out.
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The contents of operand_mismatch_kind_names were out of sync
with the enum.
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There are many opcode table entries that share the same mnemonic.
Trying to parse an invalid assembly line will trigger an error for
each of these entries, but the specific error might vary from one
entry to another, depending on the exact nature of the problem.
GAS has quite an elaborate system for picking the most appropriate
error out of all the failed matches. And in many cases it works well.
However, one of the limitations is that the error is always reported
against a single opcode table entry. If that table entry isn't the
one that the user intended to use, then the error can end up being
overly specific.
This is particularly true if an instruction has a typoed register
name, or uses a type of register that is not accepted by any
opcode table entry. For example, one of the expected error
matches for an attempted SVE2 instruction is:
Error: operand 1 must be a SIMD scalar register -- `addp z32\.s,p0/m,z32\.s,z0\.s'
even though the hypothetical user was presumably attempting to use
the SVE form of ADDP rather than the Advanced SIMD one. There are
many other instances of this in the testsuite.
The problem becomes especially acute with SME2, since many SME2
instructions reuse existing mnemonics. This could lead to us
reporting an SME-related error against a non-SME instruction,
or a non-SME-related error against an SME instruction.
This patch tries to improve things by collecting together all
the register types that an opcode table entry expected for a
given operand. It also records what kind of register was
actually seen, if any. It then tries to summarise all this
in a more directed way, falling back to a generic error if
the combination defies a neat summary.
The patch includes tests for all new messages except REG_TYPE_ZA,
which only triggers with SME2.
To test this, I created an assembly file that contained the cross
product of all known mnemonics and one example from each register
class. I then looked for cases where the new routines fell back on the
generic errors ("expected a register" or "unexpected register type").
I locally added dummy messages for each one until there were no
more hits. The patch adds a specimen instruction to diagnostics.s
for each of these combinations. In each case, the combination didn't
seem like something that could be summarised in a natural way, so the
generic messages seemed better. There's always going to be an element
of personal taste around this kind of thing though.
Adding more register types made 1<<REG_TYPE_MAX exceed the range
of the type, but we don't actually need/want 1<<REG_TYPE_MAX.
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After parsing a '{' and the first register, parse_typed_reg would
report errors in subsequent registers in the same way as for the
first register. It used set_default_error, which reports errors
of the form "operand N must be X".
The problem is that if there are multiple opcode entries for the
same mnemonic, there could be several matches that lead to a
default error. There's no guarantee that the default error for
the register list is the one that will be chosen.
To take an example from the testsuite:
ext z0.b,{z31.b,z32.b},#0
gave:
operand 2 must be an SVE vector register
with the error being reported against the single-vector version
of ext, even though the operand is clearly a list.
This patch uses set_fatal_syntax_error to bump the priority of the
error once we're sure that the operand is a list of the right type.
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parse_typed_reg is used for parsing both bare registers and
registers that occur in lists. If it doesn't see a register,
or sees an unexpected kind of register, it queues a default
error to report the problem. These default errors have the form
"operand N must be an X", where X comes from the operand table.
If there are multiple opcode entries that report default errors,
GAS tries to pick the most appropriate one, using the opcode
table order as a tiebreaker. But this can lead to cases where
a syntax error in a register list is reported against an opcode
that doesn't accept register lists. For example, the unlikely
error:
ext z0.b,{,},#0
is reported as:
operand 2 must be an SVE vector register -- `ext z0.b,{,},#0'
even though operand 2 can be a register list.
If we've parsed the opening '{' of a register list, and then see
something that isn't remotely register-like, it seems better to
report that directly as a syntax error, rather than rely on the
default error. The operand won't be a valid list of anything,
so there's no need to pick a specific Y in "operand N must be
a list of Y".
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