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encode: Add library for x86-64 encoding

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This commit is contained in:
Alexis Engelke
2020-06-24 11:20:50 +02:00
parent 4e95c8d152
commit 69ce124354
7 changed files with 817 additions and 110 deletions
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151
parseinstrs.py
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@@ -91,6 +91,13 @@ class OpKind(NamedTuple):
K_MEM = "mem"
K_IMM = "imm"
def abssize(self, opsz=None, vecsz=None):
res = opsz if self.size == self.SZ_OP else \
vecsz if self.size == self.SZ_VEC else self.size
if res is None:
raise Exception("unspecified operand size")
return res
OPKINDS = {
# sizeidx (0, fixedsz, opsz, vecsz), fixedsz (log2), regtype
"IMM": OpKind(OpKind.SZ_OP, OpKind.K_IMM),
@@ -423,6 +430,144 @@ template = """// Auto-generated file -- do not modify!
#endif
"""
def encode_table(entries):
mnemonics = defaultdict(list)
mnemonics["FE_NOP"].append(("NP", 0, 0, "0x90"))
for opcode, desc in entries:
if desc.mnemonic[:9] == "RESERVED_":
continue
if "ONLY32" in desc.flags or "UNDOC" in desc.flags:
continue
opsizes = {8} if "SIZE_8" in desc.flags else {16, 32, 64}
hasvex, vecsizes = False, {128}
opc_i = opcode.opc | (opcode.opcext[1] << 8 if opcode.opcext else 0)
opc_flags = ""
opc_flags += ["","|OPC_0F","|OPC_0F38","|OPC_0F3A"][opcode.escape]
if opcode.vex:
hasvex, vecsizes = True, {128, 256}
opc_flags += "|OPC_VEX"
if opcode.prefix:
opc_flags += ["", "|OPC_66", "|OPC_F3", "|OPC_F2"][opcode.prefix[1]]
if not opcode.prefix[0]: opsizes -= {16}
if opcode.vexl == "IG":
vecsizes = {0}
elif opcode.vexl:
vecsizes -= {128 if opcode.vexl == "1" else 256}
if opcode.vexl == "1": opc_flags += "|OPC_VEXL"
if opcode.rexw == "IG":
opsizes = {0}
elif opcode.rexw:
opsizes -= {32 if opcode.rexw == "1" else 64}
if opcode.rexw == "1": opc_flags += "|OPC_REXW"
if "DEF64" in desc.flags:
opsizes -= {32}
if "INSTR_WIDTH" not in desc.flags and all(op.size != OpKind.SZ_OP for op in desc.operands):
opsizes = {0}
if all(op.size != OpKind.SZ_VEC for op in desc.operands):
vecsizes = {0} # for VEX-encoded general-purpose instructions.
if "ENC_NOSZ" in desc.flags:
opsizes, vecsizes = {0}, {0}
# Where to put the operand size in the mnemonic
separate_opsize = "ENC_SEPSZ" in desc.flags
prepend_opsize = max(opsizes) > 0 and not separate_opsize
prepend_vecsize = hasvex and max(vecsizes) > 0 and not separate_opsize
optypes = ["", "", "", ""]
enc = ENCODINGS[desc.encoding]
if enc.modrm_idx:
if "NOMEM" in desc.flags:
optypes[enc.modrm_idx^3] = "r"
elif ((opcode.opcext and opcode.opcext[0] and opcode.opcext[1] < 8)
or desc.operands[enc.modrm_idx^3].kind == OpKind.K_MEM):
optypes[enc.modrm_idx^3] = "m"
else:
optypes[enc.modrm_idx^3] = "rm"
if enc.modreg_idx: optypes[enc.modreg_idx^3] = "r"
if enc.vexreg_idx: optypes[enc.vexreg_idx^3] = "r"
if enc.zeroreg_idx: optypes[enc.zeroreg_idx^3] = "r"
if enc.imm_control: optypes[enc.imm_idx^3] = " iariioo"[enc.imm_control]
optypes = product(*(ot for ot in optypes if ot))
prefixes = [("", "")]
if "LOCK" in desc.flags:
prefixes.append(("LOCK_", "|OPC_LOCK"))
if "ENC_REP" in desc.flags:
prefixes.append(("REP_", "|OPC_F3"))
if "ENC_REPCC" in desc.flags:
prefixes.append(("REPNZ_", "|OPC_F2"))
prefixes.append(("REPZ_", "|OPC_F3"))
for opsize, vecsize, prefix, ots in product(opsizes, vecsizes, prefixes, optypes):
if prefix[1] == "|OPC_LOCK" and ots[0] != "m":
continue
imm_size = 0
if enc.imm_control >= 4:
if desc.mnemonic == "ENTER":
imm_size = 3
elif "IMM_8" in desc.flags:
imm_size = 1
else:
max_imm_size = 4 if desc.mnemonic != "MOVABS" else 8
imm_opsize = desc.operands[enc.imm_idx^3].abssize(opsize//8)
imm_size = min(max_imm_size, imm_opsize)
tys = [] # operands that require special handling
for ot, op in zip(ots, desc.operands):
if ot == "m":
tys.append(0xf)
elif op.kind == "GP":
tys.append(2 if op.abssize(opsize//8) == 1 else 1)
else:
tys.append({
"imm": 0, "SEG": 3, "FPU": 4, "MMX": 5, "XMM": 6,
"BND": 8, "CR": 9, "DR": 10,
}.get(op.kind, -1))
tys_i = sum(ty << (4*i) for i, ty in enumerate(tys))
opc_s = hex(opc_i) + opc_flags + prefix[1]
if opsize == 16: opc_s += "|OPC_66"
if opsize == 64 and "DEF64" not in desc.flags: opc_s += "|OPC_REXW"
# Construct mnemonic name
mnem_name = {"MOVABS": "MOV", "XCHG_NOP": "XCHG"}.get(desc.mnemonic, desc.mnemonic)
name = "FE_" + prefix[0] + mnem_name
if prepend_opsize and not ("DEF64" in desc.flags and opsize == 64):
name += f"_{opsize}"[name[-1] not in "0123456789":]
if prepend_vecsize:
name += f"_{vecsize}"[name[-1] not in "0123456789":]
for ot, op in zip(ots, desc.operands):
name += ot.replace("o", "")
if separate_opsize:
name += f"{op.abssize(opsize//8, vecsize//8)*8}"
mnemonics[name].append((desc.encoding, imm_size, tys_i, opc_s))
descs = ""
alt_index = 0
for mnem, variants in sorted(mnemonics.items()):
dedup = []
for variant in variants:
if not any(x[:3] == variant[:3] for x in dedup):
dedup.append(variant)
enc_prio = ["O", "OA", "OI", "IA", "M", "MI", "MR", "RM"]
dedup.sort(key=lambda e: (e[1], e[0] in enc_prio and enc_prio.index(e[0])))
indices = [mnem] + [f"FE_MNEM_MAX+{alt_index+i}" for i in range(len(dedup) - 1)]
alt_list = indices[1:] + ["0"]
alt_index += len(alt_list) - 1
for idx, alt, (enc, immsz, tys_i, opc_s) in zip(indices, alt_list, dedup):
descs += f"[{idx}] = {{ .enc = ENC_{enc}, .immsz = {immsz}, .tys = {tys_i:#x}, .opc = {opc_s}, .alt = {alt} }},\n"
mnemonics_list = sorted(mnemonics.keys())
mnemonics_lut = {mnem: mnemonics_list.index(mnem) for mnem in mnemonics_list}
mnemonics_tab = "\n".join("FE_MNEMONIC(%s,%d)"%entry for entry in mnemonics_lut.items())
return mnemonics_tab, descs
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument("--32", dest="modes", action="append_const", const=32)
@@ -430,6 +575,8 @@ if __name__ == "__main__":
parser.add_argument("table", type=argparse.FileType('r'))
parser.add_argument("decode_mnems", type=argparse.FileType('w'))
parser.add_argument("decode_table", type=argparse.FileType('w'))
parser.add_argument("encode_mnems", type=argparse.FileType('w'))
parser.add_argument("encode_table", type=argparse.FileType('w'))
args = parser.parse_args()
entries = []
@@ -469,3 +616,7 @@ if __name__ == "__main__":
defines="\n".join("#define " + line for line in defines),
)
args.decode_table.write(decode_table)
fe_mnem_list, fe_code = encode_table(entries)
args.encode_mnems.write(fe_mnem_list)
args.encode_table.write(fe_code)