Files
wasmtime/meta/cretonne/base.py
Jakob Stoklund Olesen ad01af40e4 Generate value type constraints.
Add an Opcode::constraints() method which returns an OpcodeConstraints object.
This object provides information on instruction polymorphism and how many
results is produced.

Generate a list of TypeSet objects for checking free type variables. The type
sets are parametrized rather than being represented as fully general sets.

Add UniqueTable and UniqueSeqTable classes to the meta code generator. Use for
compressing tabular data by removing duplicates.
2016-05-20 14:43:16 -07:00

445 lines
12 KiB
Python

"""
Cretonne base instruction set.
This module defines the basic Cretonne instruction set that all targets
support.
"""
from . import TypeVar, Operand, Instruction, InstructionGroup, variable_args
from types import i8, f32, f64
from immediates import imm64, ieee32, ieee64, immvector
import entities
instructions = InstructionGroup("base", "Shared base instruction set")
Int = TypeVar('Int', 'A scalar or vector integer type', ints=True, simd=True)
iB = TypeVar('iB', 'A scalar integer type', ints=True)
Testable = TypeVar(
'Testable', 'A scalar boolean or integer type',
ints=True, bools=True)
TxN = TypeVar(
'%Tx%N', 'A SIMD vector type',
ints=True, floats=True, bools=True, scalars=False, simd=True)
#
# Control flow
#
c = Operand('c', Testable, doc='Controlling value to test')
EBB = Operand('EBB', entities.ebb, doc='Destination extended basic block')
args = Operand('args', variable_args, doc='EBB arguments')
jump = Instruction(
'jump', r"""
Jump.
Unconditionally jump to an extended basic block, passing the specified
EBB arguments. The number and types of arguments must match the
destination EBB.
""",
ins=(EBB, args), is_terminator=True)
brz = Instruction(
'brz', r"""
Branch when zero.
If ``c`` is a :type:`b1` value, take the branch when ``c`` is false. If
``c`` is an integer value, take the branch when ``c = 0``.
""",
ins=(c, EBB, args), is_branch=True)
brnz = Instruction(
'brnz', r"""
Branch when non-zero.
If ``c`` is a :type:`b1` value, take the branch when ``c`` is true. If
``c`` is an integer value, take the branch when ``c != 0``.
""",
ins=(c, EBB, args), is_branch=True)
x = Operand('x', iB, doc='index into jump table')
JT = Operand('JT', entities.jump_table)
br_table = Instruction(
'br_table', r"""
Indirect branch via jump table.
Use ``x`` as an unsigned index into the jump table ``JT``. If a jump
table entry is found, branch to the corresponding EBB. If no entry was
found fall through to the next instruction.
Note that this branch instruction can't pass arguments to the targeted
blocks. Split critical edges as needed to work around this.
""",
ins=(x, JT), is_branch=True)
trap = Instruction(
'trap', r"""
Terminate execution unconditionally.
""",
is_terminator=True)
trapz = Instruction(
'trapz', r"""
Trap when zero.
if ``c`` is non-zero, execution continues at the following instruction.
""",
ins=c)
trapnz = Instruction(
'trapnz', r"""
Trap when non-zero.
if ``c`` is zero, execution continues at the following instruction.
""",
ins=c)
#
# Materializing constants.
#
N = Operand('N', imm64)
a = Operand('a', Int, doc='A constant integer scalar or vector value')
iconst = Instruction(
'iconst', r"""
Integer constant.
Create a scalar integer SSA value with an immediate constant value, or
an integer vector where all the lanes have the same value.
""",
ins=N, outs=a)
N = Operand('N', ieee32)
a = Operand('a', f32, doc='A constant integer scalar or vector value')
f32const = Instruction(
'f32const', r"""
Floating point constant.
Create a :type:`f32` SSA value with an immediate constant value, or a
floating point vector where all the lanes have the same value.
""",
ins=N, outs=a)
N = Operand('N', ieee64)
a = Operand('a', f64, doc='A constant integer scalar or vector value')
f64const = Instruction(
'f64const', r"""
Floating point constant.
Create a :type:`f64` SSA value with an immediate constant value, or a
floating point vector where all the lanes have the same value.
""",
ins=N, outs=a)
N = Operand('N', immvector)
a = Operand('a', TxN, doc='A constant vector value')
vconst = Instruction(
'vconst', r"""
Vector constant (floating point or integer).
Create a SIMD vector value where the lanes don't have to be identical.
""",
ins=N, outs=a)
#
# Integer arithmetic
#
a = Operand('a', Int)
x = Operand('x', Int)
y = Operand('y', Int)
iadd = Instruction(
'iadd', r"""
Wrapping integer addition: :math:`a := x + y \pmod{2^B}`.
This instruction does not depend on the signed/unsigned interpretation
of the operands.
""",
ins=(x, y), outs=a)
isub = Instruction(
'isub', r"""
Wrapping integer subtraction: :math:`a := x - y \pmod{2^B}`.
This instruction does not depend on the signed/unsigned interpretation
of the operands.
""",
ins=(x, y), outs=a)
imul = Instruction(
'imul', r"""
Wrapping integer multiplication: :math:`a := x y \pmod{2^B}`.
This instruction does not depend on the signed/unsigned interpretation
of the
operands.
Polymorphic over all integer types (vector and scalar).
""",
ins=(x, y), outs=a)
udiv = Instruction(
'udiv', r"""
Unsigned integer division: :math:`a := \lfloor {x \over y} \rfloor`.
This operation traps if the divisor is zero.
""",
ins=(x, y), outs=a)
sdiv = Instruction(
'sdiv', r"""
Signed integer division rounded toward zero: :math:`a := sign(xy)
\lfloor {|x| \over |y|}\rfloor`.
This operation traps if the divisor is zero, or if the result is not
representable in :math:`B` bits two's complement. This only happens
when :math:`x = -2^{B-1}, y = -1`.
""",
ins=(x, y), outs=a)
urem = Instruction(
'urem', """
Unsigned integer remainder.
This operation traps if the divisor is zero.
""",
ins=(x, y), outs=a)
srem = Instruction(
'srem', """
Signed integer remainder.
This operation traps if the divisor is zero.
.. todo:: Integer remainder vs modulus.
Clarify whether the result has the sign of the divisor or the dividend.
Should we add a ``smod`` instruction for the case where the result has
the same sign as the divisor?
""",
ins=(x, y), outs=a)
a = Operand('a', iB)
x = Operand('x', iB)
Y = Operand('Y', imm64)
iadd_imm = Instruction(
'iadd_imm', """
Add immediate integer.
Same as :inst:`iadd`, but one operand is an immediate constant.
Polymorphic over all scalar integer types, but does not support vector
types.
""",
ins=(x, Y), outs=a)
imul_imm = Instruction(
'imul_imm', """
Integer multiplication by immediate constant.
Polymorphic over all scalar integer types.
""",
ins=(x, Y), outs=a)
udiv_imm = Instruction(
'udiv_imm', """
Unsigned integer division by an immediate constant.
This instruction never traps because a divisor of zero is not allowed.
""",
ins=(x, Y), outs=a)
sdiv_imm = Instruction(
'sdiv_imm', """
Signed integer division by an immediate constant.
This instruction never traps because a divisor of -1 or 0 is not
allowed. """,
ins=(x, Y), outs=a)
urem_imm = Instruction(
'urem_imm', """
Unsigned integer remainder with immediate divisor.
This instruction never traps because a divisor of zero is not allowed.
""",
ins=(x, Y), outs=a)
srem_imm = Instruction(
'srem_imm', """
Signed integer remainder with immediate divisor.
This instruction never traps because a divisor of 0 or -1 is not
allowed. """,
ins=(x, Y), outs=a)
# Swap x and y for isub_imm.
X = Operand('X', imm64)
y = Operand('y', iB)
isub_imm = Instruction(
'isub_imm', """
Immediate wrapping subtraction: :math:`a := X - y \pmod{2^B}`.
Also works as integer negation when :math:`X = 0`. Use :inst:`iadd_imm`
with a negative immediate operand for the reverse immediate
subtraction.
Polymorphic over all scalar integer types, but does not support vector
types.
""",
ins=(X, y), outs=a)
#
# Bitwise operations.
#
# TODO: Which types should permit boolean operations? Any reason to restrict?
bits = TypeVar(
'bits', 'Any integer, float, or boolean scalar or vector type',
ints=True, floats=True, bools=True, scalars=True, simd=True)
x = Operand('x', bits)
y = Operand('y', bits)
a = Operand('a', bits)
band = Instruction(
'band', """
Bitwise and.
""",
ins=(x, y), outs=a)
bor = Instruction(
'bor', """
Bitwise or.
""",
ins=(x, y), outs=a)
bxor = Instruction(
'bxor', """
Bitwise xor.
""",
ins=(x, y), outs=a)
bnot = Instruction(
'bnot', """
Bitwise not.
""",
ins=x, outs=a)
# Shift/rotate.
x = Operand('x', Int, doc='Scalar or vector value to shift')
y = Operand('y', iB, doc='Number of bits to shift')
a = Operand('a', Int)
rotl = Instruction(
'rotl', r"""
Rotate left.
Rotate the bits in ``x`` by ``y`` places.
""",
ins=(x, y), outs=a)
rotr = Instruction(
'rotr', r"""
Rotate right.
Rotate the bits in ``x`` by ``y`` places.
""",
ins=(x, y), outs=a)
ishl = Instruction(
'ishl', r"""
Integer shift left. Shift the bits in ``x`` towards the MSB by ``y``
places. Shift in zero bits to the LSB.
The shift amount is masked to the size of ``x``.
When shifting a B-bits integer type, this instruction computes:
.. math::
s &:= y \pmod B, \\
a &:= x \cdot 2^s \pmod{2^B}.
.. todo:: Add ``ishl_imm`` variant with an immediate ``y``.
""",
ins=(x, y), outs=a)
ushr = Instruction(
'ushr', r"""
Unsigned shift right. Shift bits in ``x`` towards the LSB by ``y``
places, shifting in zero bits to the MSB. Also called a *logical
shift*.
The shift amount is masked to the size of the register.
When shifting a B-bits integer type, this instruction computes:
.. math::
s &:= y \pmod B, \\
a &:= \lfloor x \cdot 2^{-s} \rfloor.
.. todo:: Add ``ushr_imm`` variant with an immediate ``y``.
""",
ins=(x, y), outs=a)
sshr = Instruction(
'sshr', r"""
Signed shift right. Shift bits in ``x`` towards the LSB by ``y``
places, shifting in sign bits to the MSB. Also called an *arithmetic
shift*.
The shift amount is masked to the size of the register.
.. todo:: Add ``sshr_imm`` variant with an immediate ``y``.
""",
ins=(x, y), outs=a)
#
# Bit counting.
#
x = Operand('x', iB)
a = Operand('a', i8)
clz = Instruction(
'clz', r"""
Count leading zero bits.
Starting from the MSB in ``x``, count the number of zero bits before
reaching the first one bit. When ``x`` is zero, returns the size of x
in bits.
""",
ins=x, outs=a)
cls = Instruction(
'cls', r"""
Count leading sign bits.
Starting from the MSB after the sign bit in ``x``, count the number of
consecutive bits identical to the sign bit. When ``x`` is 0 or -1,
returns one less than the size of x in bits.
""",
ins=x, outs=a)
ctz = Instruction(
'ctz', r"""
Count trailing zeros.
Starting from the LSB in ``x``, count the number of zero bits before
reaching the first one bit. When ``x`` is zero, returns the size of x
in bits.
""",
ins=x, outs=a)
popcnt = Instruction(
'popcnt', r"""
Population count
Count the number of one bits in ``x``.
""",
ins=x, outs=a)
instructions.close()