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384 lines
15 KiB
Python
384 lines
15 KiB
Python
"""Core data structures for compiled code templates."""
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import dataclasses
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import enum
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import sys
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import typing
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import _schema
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@enum.unique
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class HoleValue(enum.Enum):
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"""
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Different "base" values that can be patched into holes (usually combined with the
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address of a symbol and/or an addend).
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"""
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# The base address of the machine code for the current uop (exposed as _JIT_ENTRY):
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CODE = enum.auto()
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# The base address of the machine code for the next uop (exposed as _JIT_CONTINUE):
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CONTINUE = enum.auto()
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# The base address of the read-only data for this uop:
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DATA = enum.auto()
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# The address of the current executor (exposed as _JIT_EXECUTOR):
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EXECUTOR = enum.auto()
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# The base address of the "global" offset table located in the read-only data.
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# Shouldn't be present in the final stencils, since these are all replaced with
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# equivalent DATA values:
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GOT = enum.auto()
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# The current uop's oparg (exposed as _JIT_OPARG):
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OPARG = enum.auto()
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# The current uop's operand on 64-bit platforms (exposed as _JIT_OPERAND):
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OPERAND = enum.auto()
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# The current uop's operand on 32-bit platforms (exposed as _JIT_OPERAND_HI/LO):
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OPERAND_HI = enum.auto()
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OPERAND_LO = enum.auto()
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# The current uop's target (exposed as _JIT_TARGET):
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TARGET = enum.auto()
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# The base address of the machine code for the jump target (exposed as _JIT_JUMP_TARGET):
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JUMP_TARGET = enum.auto()
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# The base address of the machine code for the error jump target (exposed as _JIT_ERROR_TARGET):
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ERROR_TARGET = enum.auto()
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# The index of the exit to be jumped through (exposed as _JIT_EXIT_INDEX):
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EXIT_INDEX = enum.auto()
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# The base address of the machine code for the first uop (exposed as _JIT_TOP):
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TOP = enum.auto()
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# A hardcoded value of zero (used for symbol lookups):
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ZERO = enum.auto()
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# Map relocation types to our JIT's patch functions. "r" suffixes indicate that
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# the patch function is relative. "x" suffixes indicate that they are "relaxing"
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# (see comments in jit.c for more info):
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_PATCH_FUNCS = {
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# aarch64-apple-darwin:
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"ARM64_RELOC_BRANCH26": "patch_aarch64_26r",
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"ARM64_RELOC_GOT_LOAD_PAGE21": "patch_aarch64_21rx",
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"ARM64_RELOC_GOT_LOAD_PAGEOFF12": "patch_aarch64_12x",
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"ARM64_RELOC_PAGE21": "patch_aarch64_21r",
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"ARM64_RELOC_PAGEOFF12": "patch_aarch64_12",
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"ARM64_RELOC_UNSIGNED": "patch_64",
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# x86_64-pc-windows-msvc:
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"IMAGE_REL_AMD64_REL32": "patch_x86_64_32rx",
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# aarch64-pc-windows-msvc:
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"IMAGE_REL_ARM64_BRANCH26": "patch_aarch64_26r",
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"IMAGE_REL_ARM64_PAGEBASE_REL21": "patch_aarch64_21rx",
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"IMAGE_REL_ARM64_PAGEOFFSET_12A": "patch_aarch64_12",
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"IMAGE_REL_ARM64_PAGEOFFSET_12L": "patch_aarch64_12x",
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# i686-pc-windows-msvc:
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"IMAGE_REL_I386_DIR32": "patch_32",
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"IMAGE_REL_I386_REL32": "patch_x86_64_32rx",
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# aarch64-unknown-linux-gnu:
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"R_AARCH64_ABS64": "patch_64",
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"R_AARCH64_ADD_ABS_LO12_NC": "patch_aarch64_12",
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"R_AARCH64_ADR_GOT_PAGE": "patch_aarch64_21rx",
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"R_AARCH64_ADR_PREL_PG_HI21": "patch_aarch64_21r",
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"R_AARCH64_CALL26": "patch_aarch64_26r",
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"R_AARCH64_JUMP26": "patch_aarch64_26r",
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"R_AARCH64_LD64_GOT_LO12_NC": "patch_aarch64_12x",
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"R_AARCH64_MOVW_UABS_G0_NC": "patch_aarch64_16a",
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"R_AARCH64_MOVW_UABS_G1_NC": "patch_aarch64_16b",
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"R_AARCH64_MOVW_UABS_G2_NC": "patch_aarch64_16c",
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"R_AARCH64_MOVW_UABS_G3": "patch_aarch64_16d",
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# x86_64-unknown-linux-gnu:
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"R_X86_64_64": "patch_64",
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"R_X86_64_GOTPCREL": "patch_32r",
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"R_X86_64_GOTPCRELX": "patch_x86_64_32rx",
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"R_X86_64_PC32": "patch_32r",
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"R_X86_64_REX_GOTPCRELX": "patch_x86_64_32rx",
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# x86_64-apple-darwin:
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"X86_64_RELOC_BRANCH": "patch_32r",
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"X86_64_RELOC_GOT": "patch_x86_64_32rx",
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"X86_64_RELOC_GOT_LOAD": "patch_x86_64_32rx",
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"X86_64_RELOC_SIGNED": "patch_32r",
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"X86_64_RELOC_UNSIGNED": "patch_64",
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}
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# Translate HoleValues to C expressions:
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_HOLE_EXPRS = {
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HoleValue.CODE: "(uintptr_t)code",
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HoleValue.CONTINUE: "(uintptr_t)code + sizeof(code_body)",
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HoleValue.DATA: "(uintptr_t)data",
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HoleValue.EXECUTOR: "(uintptr_t)executor",
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# These should all have been turned into DATA values by process_relocations:
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# HoleValue.GOT: "",
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HoleValue.OPARG: "instruction->oparg",
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HoleValue.OPERAND: "instruction->operand",
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HoleValue.OPERAND_HI: "(instruction->operand >> 32)",
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HoleValue.OPERAND_LO: "(instruction->operand & UINT32_MAX)",
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HoleValue.TARGET: "instruction->target",
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HoleValue.JUMP_TARGET: "instruction_starts[instruction->jump_target]",
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HoleValue.ERROR_TARGET: "instruction_starts[instruction->error_target]",
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HoleValue.EXIT_INDEX: "instruction->exit_index",
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HoleValue.TOP: "instruction_starts[1]",
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HoleValue.ZERO: "",
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}
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@dataclasses.dataclass
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class Hole:
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"""
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A "hole" in the stencil to be patched with a computed runtime value.
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Analogous to relocation records in an object file.
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"""
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offset: int
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kind: _schema.HoleKind
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# Patch with this base value:
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value: HoleValue
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# ...plus the address of this symbol:
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symbol: str | None
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# ...plus this addend:
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addend: int
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func: str = dataclasses.field(init=False)
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# Convenience method:
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replace = dataclasses.replace
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def __post_init__(self) -> None:
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self.func = _PATCH_FUNCS[self.kind]
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def fold(self, other: typing.Self) -> typing.Self | None:
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"""Combine two holes into a single hole, if possible."""
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if (
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self.offset + 4 == other.offset
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and self.value == other.value
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and self.symbol == other.symbol
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and self.addend == other.addend
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and self.func == "patch_aarch64_21rx"
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and other.func == "patch_aarch64_12x"
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):
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# These can *only* be properly relaxed when they appear together and
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# patch the same value:
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folded = self.replace()
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folded.func = "patch_aarch64_33rx"
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return folded
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return None
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def as_c(self, where: str) -> str:
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"""Dump this hole as a call to a patch_* function."""
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location = f"{where} + {self.offset:#x}"
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value = _HOLE_EXPRS[self.value]
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if self.symbol:
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if value:
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value += " + "
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value += f"(uintptr_t)&{self.symbol}"
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if _signed(self.addend):
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if value:
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value += " + "
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value += f"{_signed(self.addend):#x}"
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return f"{self.func}({location}, {value});"
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@dataclasses.dataclass
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class Stencil:
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"""
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A contiguous block of machine code or data to be copied-and-patched.
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Analogous to a section or segment in an object file.
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"""
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body: bytearray = dataclasses.field(default_factory=bytearray, init=False)
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holes: list[Hole] = dataclasses.field(default_factory=list, init=False)
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disassembly: list[str] = dataclasses.field(default_factory=list, init=False)
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def pad(self, alignment: int) -> None:
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"""Pad the stencil to the given alignment."""
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offset = len(self.body)
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padding = -offset % alignment
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self.disassembly.append(f"{offset:x}: {' '.join(['00'] * padding)}")
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self.body.extend([0] * padding)
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def emit_aarch64_trampoline(self, hole: Hole) -> None:
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"""Even with the large code model, AArch64 Linux insists on 28-bit jumps."""
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base = len(self.body)
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where = slice(hole.offset, hole.offset + 4)
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instruction = int.from_bytes(self.body[where], sys.byteorder)
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instruction &= 0xFC000000
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instruction |= ((base - hole.offset) >> 2) & 0x03FFFFFF
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self.body[where] = instruction.to_bytes(4, sys.byteorder)
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self.disassembly += [
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f"{base + 4 * 0:x}: d2800008 mov x8, #0x0",
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f"{base + 4 * 0:016x}: R_AARCH64_MOVW_UABS_G0_NC {hole.symbol}",
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f"{base + 4 * 1:x}: f2a00008 movk x8, #0x0, lsl #16",
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f"{base + 4 * 1:016x}: R_AARCH64_MOVW_UABS_G1_NC {hole.symbol}",
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f"{base + 4 * 2:x}: f2c00008 movk x8, #0x0, lsl #32",
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f"{base + 4 * 2:016x}: R_AARCH64_MOVW_UABS_G2_NC {hole.symbol}",
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f"{base + 4 * 3:x}: f2e00008 movk x8, #0x0, lsl #48",
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f"{base + 4 * 3:016x}: R_AARCH64_MOVW_UABS_G3 {hole.symbol}",
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f"{base + 4 * 4:x}: d61f0100 br x8",
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]
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for code in [
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0xD2800008.to_bytes(4, sys.byteorder),
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0xF2A00008.to_bytes(4, sys.byteorder),
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0xF2C00008.to_bytes(4, sys.byteorder),
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0xF2E00008.to_bytes(4, sys.byteorder),
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0xD61F0100.to_bytes(4, sys.byteorder),
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]:
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self.body.extend(code)
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for i, kind in enumerate(
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[
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"R_AARCH64_MOVW_UABS_G0_NC",
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"R_AARCH64_MOVW_UABS_G1_NC",
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"R_AARCH64_MOVW_UABS_G2_NC",
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"R_AARCH64_MOVW_UABS_G3",
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]
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):
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self.holes.append(hole.replace(offset=base + 4 * i, kind=kind))
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def remove_jump(self, *, alignment: int = 1) -> None:
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"""Remove a zero-length continuation jump, if it exists."""
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hole = max(self.holes, key=lambda hole: hole.offset)
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match hole:
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case Hole(
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offset=offset,
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kind="IMAGE_REL_AMD64_REL32",
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value=HoleValue.GOT,
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symbol="_JIT_CONTINUE",
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addend=-4,
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) as hole:
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# jmp qword ptr [rip]
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jump = b"\x48\xFF\x25\x00\x00\x00\x00"
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offset -= 3
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case Hole(
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offset=offset,
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kind="IMAGE_REL_I386_REL32" | "X86_64_RELOC_BRANCH",
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value=HoleValue.CONTINUE,
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symbol=None,
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addend=-4,
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) as hole:
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# jmp 5
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jump = b"\xE9\x00\x00\x00\x00"
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offset -= 1
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case Hole(
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offset=offset,
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kind="R_AARCH64_JUMP26",
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value=HoleValue.CONTINUE,
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symbol=None,
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addend=0,
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) as hole:
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# b #4
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jump = b"\x00\x00\x00\x14"
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case Hole(
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offset=offset,
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kind="R_X86_64_GOTPCRELX",
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value=HoleValue.GOT,
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symbol="_JIT_CONTINUE",
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addend=addend,
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) as hole:
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assert _signed(addend) == -4
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# jmp qword ptr [rip]
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jump = b"\xFF\x25\x00\x00\x00\x00"
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offset -= 2
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case _:
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return
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if self.body[offset:] == jump and offset % alignment == 0:
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self.body = self.body[:offset]
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self.holes.remove(hole)
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@dataclasses.dataclass
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class StencilGroup:
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"""
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Code and data corresponding to a given micro-opcode.
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Analogous to an entire object file.
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"""
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code: Stencil = dataclasses.field(default_factory=Stencil, init=False)
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data: Stencil = dataclasses.field(default_factory=Stencil, init=False)
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symbols: dict[int | str, tuple[HoleValue, int]] = dataclasses.field(
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default_factory=dict, init=False
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)
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_got: dict[str, int] = dataclasses.field(default_factory=dict, init=False)
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def process_relocations(self, *, alignment: int = 1) -> None:
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"""Fix up all GOT and internal relocations for this stencil group."""
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for hole in self.code.holes.copy():
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if (
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hole.kind
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in {"R_AARCH64_CALL26", "R_AARCH64_JUMP26", "ARM64_RELOC_BRANCH26"}
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and hole.value is HoleValue.ZERO
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):
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self.code.pad(alignment)
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self.code.emit_aarch64_trampoline(hole)
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self.code.holes.remove(hole)
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self.code.remove_jump(alignment=alignment)
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self.code.pad(alignment)
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self.data.pad(8)
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for stencil in [self.code, self.data]:
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for hole in stencil.holes:
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if hole.value is HoleValue.GOT:
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assert hole.symbol is not None
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hole.value = HoleValue.DATA
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hole.addend += self._global_offset_table_lookup(hole.symbol)
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hole.symbol = None
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elif hole.symbol in self.symbols:
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hole.value, addend = self.symbols[hole.symbol]
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hole.addend += addend
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hole.symbol = None
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elif (
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hole.kind in {"IMAGE_REL_AMD64_REL32"}
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and hole.value is HoleValue.ZERO
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):
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raise ValueError(
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f"Add PyAPI_FUNC(...) or PyAPI_DATA(...) to declaration of {hole.symbol}!"
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)
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self._emit_global_offset_table()
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self.code.holes.sort(key=lambda hole: hole.offset)
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self.data.holes.sort(key=lambda hole: hole.offset)
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def _global_offset_table_lookup(self, symbol: str) -> int:
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return len(self.data.body) + self._got.setdefault(symbol, 8 * len(self._got))
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def _emit_global_offset_table(self) -> None:
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got = len(self.data.body)
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for s, offset in self._got.items():
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if s in self.symbols:
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value, addend = self.symbols[s]
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symbol = None
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else:
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value, symbol = symbol_to_value(s)
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addend = 0
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self.data.holes.append(
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Hole(got + offset, "R_X86_64_64", value, symbol, addend)
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)
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value_part = value.name if value is not HoleValue.ZERO else ""
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if value_part and not symbol and not addend:
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addend_part = ""
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else:
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signed = "+" if symbol is not None else ""
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addend_part = f"&{symbol}" if symbol else ""
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addend_part += f"{_signed(addend):{signed}#x}"
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if value_part:
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value_part += "+"
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self.data.disassembly.append(
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f"{len(self.data.body):x}: {value_part}{addend_part}"
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)
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self.data.body.extend([0] * 8)
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def as_c(self, opname: str) -> str:
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"""Dump this hole as a StencilGroup initializer."""
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return f"{{emit_{opname}, {len(self.code.body)}, {len(self.data.body)}}}"
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def symbol_to_value(symbol: str) -> tuple[HoleValue, str | None]:
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"""
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Convert a symbol name to a HoleValue and a symbol name.
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Some symbols (starting with "_JIT_") are special and are converted to their
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own HoleValues.
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"""
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if symbol.startswith("_JIT_"):
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try:
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return HoleValue[symbol.removeprefix("_JIT_")], None
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except KeyError:
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pass
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return HoleValue.ZERO, symbol
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def _signed(value: int) -> int:
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value %= 1 << 64
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if value & (1 << 63):
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value -= 1 << 64
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return value
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