10. Writing Your Own Plugins¶
RISCV-ISAC uses the pluggy system for supporting plugins. The hooks are predefined and can be accessed by importing the riscv_isac.plugins
module. The template for custom plugins is available here..
Two classes of plugins are defined, namely:
Parser Plugin(
parserHookImpl
): Parse the execution trace file to yield instruction (code), mnemonics, address and register commit value for each instruction. Currently, there are plugins for execution traces from 2 RISC V models - SPIKE and SAIL.Decoder Plugin(
decoderHookImpl
): Decodes the information into a common instruction class object.
10.1. Function Definitions¶
10.1.1. Parser Plugin¶
10.1.1.1. def setup(self, trace, arch):¶
This function initializes each instance of parserclass()
(a subclass of ParserSpec
) of a given mode.
Arguments: (
trace
) file path of the execution trace file and (arch
) architecture of the set.
@plugins.parserHookImpl
def setup(self, trace, arch):
self.trace = trace
self.arch = arch
10.1.1.2. def __iter__(self):¶
It converts the instance of parserclass()
to an iterator. Thus, given an input trace file to the instance, this function will extract information from it line by line. An example is shown below from the c_sail parser.
Arguments:
self
instance of the class that contains the input trace file.Returns: Generates instruction (
instr
), mnemonics (mnemonic
), address (addr
) and register commit value (commitvalue
) on each call.
@plugins.parserHookImpl
def __iter__(self):
with open(self.trace) as fp:
content = fp.read()
instructions = content.split('\n\n')
for line in instructions:
instr, mnemonic = self.extractInstruction(line)
addr = self.extractAddress(line)
commitvalue = self.extractRegisterCommitVal(line)
yield instr, mnemonic, addr, commitvalue
10.1.2. Decoder Plugin¶
10.1.2.1. def setup(self, arch):¶
This function initializes each instance of decoderclass()
(a subclass of DecoderSpec
).
Arguments-
self
instance of the class andarch
architecture of the instruction set
@plugins.decoderHookImpl
def setup(self, arch):
self.arch = arch
10.1.2.2. def decode(self, instr, addr):¶
This function decodes the instruction and returns an instruction object riscv_isac.InstructionObject.instructionObject
.
Arguments:
self
instance of the class,instr
Hexcode of instruction andaddr
address.Return value: The instruction object in the standard format - (instr_name, instr_addr, rd, rs1, rs2, rs3, imm, csr, shamt)
@plugins.decoderHookImpl
def decode(self, instr, addr):
''' Decodes the type of instruction
Returns: instruction object
'''
first_two_bits = self.FIRST2_MASK & instr
if first_two_bits == 0b11:
return self.parseStandardInstruction(instr, addr, self.arch)
else:
return self.parseCompressedInstruction(instr, addr, self.arch)
10.2. Templates¶
10.2.1. Parser Plugin¶
import riscv_isac.plugins
class CustomParser()
@plugins.parserHookImpl
def setup(self, trace, arch):
self.trace = trace
self.arch = arch
@plugins.parserHookImpl
def __iter__(self):
#extract instruction, mnemonic, addr and commit value
yield instr, mnemonic, addr, commitval
10.2.2. Decoder Plugin¶
from riscv_isac.plugins import decoderHookImpl
from riscv_isac.InstructionObject import instructionObject
class CustomDecoder()
@decoderHookImpl
def setup(self, arch):
self.arch = arch
@decoderHookImpl
def decode(self, instr, addr):
# construct Instruction Object and return