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f6d9e5926b
Add an option (--enable-experimental-jit for configure-based builds or --experimental-jit for PCbuild-based ones) to build an *experimental* just-in-time compiler, based on copy-and-patch (https://fredrikbk.com/publications/copy-and-patch.pdf). See Tools/jit/README.md for more information on how to install the required build-time tooling.
394 lines
15 KiB
Python
394 lines
15 KiB
Python
"""Target-specific code generation, parsing, and processing."""
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import asyncio
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import dataclasses
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import hashlib
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import json
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import os
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import pathlib
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import re
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import sys
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import tempfile
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import typing
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import _llvm
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import _schema
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import _stencils
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import _writer
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if sys.version_info < (3, 11):
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raise RuntimeError("Building the JIT compiler requires Python 3.11 or newer!")
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TOOLS_JIT_BUILD = pathlib.Path(__file__).resolve()
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TOOLS_JIT = TOOLS_JIT_BUILD.parent
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TOOLS = TOOLS_JIT.parent
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CPYTHON = TOOLS.parent
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PYTHON_EXECUTOR_CASES_C_H = CPYTHON / "Python" / "executor_cases.c.h"
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TOOLS_JIT_TEMPLATE_C = TOOLS_JIT / "template.c"
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_S = typing.TypeVar("_S", _schema.COFFSection, _schema.ELFSection, _schema.MachOSection)
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_R = typing.TypeVar(
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"_R", _schema.COFFRelocation, _schema.ELFRelocation, _schema.MachORelocation
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)
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@dataclasses.dataclass
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class _Target(typing.Generic[_S, _R]):
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triple: str
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_: dataclasses.KW_ONLY
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alignment: int = 1
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prefix: str = ""
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debug: bool = False
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force: bool = False
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verbose: bool = False
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def _compute_digest(self, out: pathlib.Path) -> str:
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hasher = hashlib.sha256()
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hasher.update(self.triple.encode())
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hasher.update(self.alignment.to_bytes())
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hasher.update(self.prefix.encode())
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# These dependencies are also reflected in _JITSources in regen.targets:
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hasher.update(PYTHON_EXECUTOR_CASES_C_H.read_bytes())
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hasher.update((out / "pyconfig.h").read_bytes())
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for dirpath, _, filenames in sorted(os.walk(TOOLS_JIT)):
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for filename in filenames:
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hasher.update(pathlib.Path(dirpath, filename).read_bytes())
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return hasher.hexdigest()
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async def _parse(self, path: pathlib.Path) -> _stencils.StencilGroup:
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group = _stencils.StencilGroup()
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args = ["--disassemble", "--reloc", f"{path}"]
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output = await _llvm.maybe_run("llvm-objdump", args, echo=self.verbose)
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if output is not None:
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group.code.disassembly.extend(
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line.expandtabs().strip()
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for line in output.splitlines()
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if not line.isspace()
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)
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args = [
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"--elf-output-style=JSON",
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"--expand-relocs",
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# "--pretty-print",
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"--section-data",
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"--section-relocations",
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"--section-symbols",
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"--sections",
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f"{path}",
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]
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output = await _llvm.run("llvm-readobj", args, echo=self.verbose)
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# --elf-output-style=JSON is only *slightly* broken on Mach-O...
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output = output.replace("PrivateExtern\n", "\n")
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output = output.replace("Extern\n", "\n")
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# ...and also COFF:
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output = output[output.index("[", 1, None) :]
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output = output[: output.rindex("]", None, -1) + 1]
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sections: list[dict[typing.Literal["Section"], _S]] = json.loads(output)
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for wrapped_section in sections:
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self._handle_section(wrapped_section["Section"], group)
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assert group.symbols["_JIT_ENTRY"] == (_stencils.HoleValue.CODE, 0)
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if group.data.body:
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line = f"0: {str(bytes(group.data.body)).removeprefix('b')}"
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group.data.disassembly.append(line)
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group.process_relocations()
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return group
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def _handle_section(self, section: _S, group: _stencils.StencilGroup) -> None:
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raise NotImplementedError(type(self))
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def _handle_relocation(
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self, base: int, relocation: _R, raw: bytes
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) -> _stencils.Hole:
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raise NotImplementedError(type(self))
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async def _compile(
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self, opname: str, c: pathlib.Path, tempdir: pathlib.Path
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) -> _stencils.StencilGroup:
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o = tempdir / f"{opname}.o"
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args = [
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f"--target={self.triple}",
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"-DPy_BUILD_CORE",
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"-D_DEBUG" if self.debug else "-DNDEBUG",
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f"-D_JIT_OPCODE={opname}",
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"-D_PyJIT_ACTIVE",
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"-D_Py_JIT",
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"-I.",
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f"-I{CPYTHON / 'Include'}",
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f"-I{CPYTHON / 'Include' / 'internal'}",
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f"-I{CPYTHON / 'Include' / 'internal' / 'mimalloc'}",
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f"-I{CPYTHON / 'Python'}",
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"-O3",
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"-c",
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"-fno-asynchronous-unwind-tables",
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# SET_FUNCTION_ATTRIBUTE on 32-bit Windows debug builds:
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"-fno-jump-tables",
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# Position-independent code adds indirection to every load and jump:
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"-fno-pic",
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# Don't make calls to weird stack-smashing canaries:
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"-fno-stack-protector",
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# We have three options for code model:
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# - "small": the default, assumes that code and data reside in the
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# lowest 2GB of memory (128MB on aarch64)
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# - "medium": assumes that code resides in the lowest 2GB of memory,
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# and makes no assumptions about data (not available on aarch64)
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# - "large": makes no assumptions about either code or data
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"-mcmodel=large",
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"-o",
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f"{o}",
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"-std=c11",
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f"{c}",
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]
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await _llvm.run("clang", args, echo=self.verbose)
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return await self._parse(o)
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async def _build_stencils(self) -> dict[str, _stencils.StencilGroup]:
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generated_cases = PYTHON_EXECUTOR_CASES_C_H.read_text()
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opnames = sorted(re.findall(r"\n {8}case (\w+): \{\n", generated_cases))
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tasks = []
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with tempfile.TemporaryDirectory() as tempdir:
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work = pathlib.Path(tempdir).resolve()
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async with asyncio.TaskGroup() as group:
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for opname in opnames:
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coro = self._compile(opname, TOOLS_JIT_TEMPLATE_C, work)
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tasks.append(group.create_task(coro, name=opname))
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return {task.get_name(): task.result() for task in tasks}
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def build(self, out: pathlib.Path, *, comment: str = "") -> None:
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"""Build jit_stencils.h in the given directory."""
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digest = f"// {self._compute_digest(out)}\n"
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jit_stencils = out / "jit_stencils.h"
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if (
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not self.force
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and jit_stencils.exists()
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and jit_stencils.read_text().startswith(digest)
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):
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return
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stencil_groups = asyncio.run(self._build_stencils())
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with jit_stencils.open("w") as file:
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file.write(digest)
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if comment:
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file.write(f"// {comment}\n")
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file.write("")
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for line in _writer.dump(stencil_groups):
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file.write(f"{line}\n")
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class _COFF(
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_Target[_schema.COFFSection, _schema.COFFRelocation]
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): # pylint: disable = too-few-public-methods
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def _handle_section(
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self, section: _schema.COFFSection, group: _stencils.StencilGroup
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) -> None:
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flags = {flag["Name"] for flag in section["Characteristics"]["Flags"]}
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if "SectionData" in section:
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section_data_bytes = section["SectionData"]["Bytes"]
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else:
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# Zeroed BSS data, seen with printf debugging calls:
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section_data_bytes = [0] * section["RawDataSize"]
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if "IMAGE_SCN_MEM_EXECUTE" in flags:
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value = _stencils.HoleValue.CODE
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stencil = group.code
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elif "IMAGE_SCN_MEM_READ" in flags:
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value = _stencils.HoleValue.DATA
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stencil = group.data
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else:
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return
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base = len(stencil.body)
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group.symbols[section["Number"]] = value, base
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stencil.body.extend(section_data_bytes)
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for wrapped_symbol in section["Symbols"]:
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symbol = wrapped_symbol["Symbol"]
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offset = base + symbol["Value"]
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name = symbol["Name"]
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name = name.removeprefix(self.prefix)
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group.symbols[name] = value, offset
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for wrapped_relocation in section["Relocations"]:
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relocation = wrapped_relocation["Relocation"]
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hole = self._handle_relocation(base, relocation, stencil.body)
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stencil.holes.append(hole)
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def _handle_relocation(
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self, base: int, relocation: _schema.COFFRelocation, raw: bytes
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) -> _stencils.Hole:
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match relocation:
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case {
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"Offset": offset,
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"Symbol": s,
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"Type": {"Value": "IMAGE_REL_AMD64_ADDR64" as kind},
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}:
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offset += base
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s = s.removeprefix(self.prefix)
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value, symbol = _stencils.symbol_to_value(s)
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addend = int.from_bytes(raw[offset : offset + 8], "little")
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case {
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"Offset": offset,
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"Symbol": s,
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"Type": {"Value": "IMAGE_REL_I386_DIR32" as kind},
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}:
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offset += base
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s = s.removeprefix(self.prefix)
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value, symbol = _stencils.symbol_to_value(s)
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addend = int.from_bytes(raw[offset : offset + 4], "little")
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case _:
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raise NotImplementedError(relocation)
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return _stencils.Hole(offset, kind, value, symbol, addend)
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class _ELF(
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_Target[_schema.ELFSection, _schema.ELFRelocation]
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): # pylint: disable = too-few-public-methods
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def _handle_section(
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self, section: _schema.ELFSection, group: _stencils.StencilGroup
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) -> None:
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section_type = section["Type"]["Value"]
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flags = {flag["Name"] for flag in section["Flags"]["Flags"]}
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if section_type == "SHT_RELA":
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assert "SHF_INFO_LINK" in flags, flags
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assert not section["Symbols"]
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value, base = group.symbols[section["Info"]]
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if value is _stencils.HoleValue.CODE:
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stencil = group.code
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else:
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assert value is _stencils.HoleValue.DATA
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stencil = group.data
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for wrapped_relocation in section["Relocations"]:
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relocation = wrapped_relocation["Relocation"]
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hole = self._handle_relocation(base, relocation, stencil.body)
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stencil.holes.append(hole)
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elif section_type == "SHT_PROGBITS":
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if "SHF_ALLOC" not in flags:
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return
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if "SHF_EXECINSTR" in flags:
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value = _stencils.HoleValue.CODE
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stencil = group.code
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else:
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value = _stencils.HoleValue.DATA
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stencil = group.data
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group.symbols[section["Index"]] = value, len(stencil.body)
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for wrapped_symbol in section["Symbols"]:
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symbol = wrapped_symbol["Symbol"]
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offset = len(stencil.body) + symbol["Value"]
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name = symbol["Name"]["Value"]
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name = name.removeprefix(self.prefix)
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group.symbols[name] = value, offset
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stencil.body.extend(section["SectionData"]["Bytes"])
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assert not section["Relocations"]
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else:
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assert section_type in {
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"SHT_GROUP",
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"SHT_LLVM_ADDRSIG",
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"SHT_NULL",
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"SHT_STRTAB",
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"SHT_SYMTAB",
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}, section_type
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def _handle_relocation(
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self, base: int, relocation: _schema.ELFRelocation, raw: bytes
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) -> _stencils.Hole:
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match relocation:
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case {
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"Addend": addend,
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"Offset": offset,
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"Symbol": {"Value": s},
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"Type": {"Value": kind},
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}:
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offset += base
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s = s.removeprefix(self.prefix)
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value, symbol = _stencils.symbol_to_value(s)
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case _:
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raise NotImplementedError(relocation)
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return _stencils.Hole(offset, kind, value, symbol, addend)
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class _MachO(
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_Target[_schema.MachOSection, _schema.MachORelocation]
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): # pylint: disable = too-few-public-methods
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def _handle_section(
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self, section: _schema.MachOSection, group: _stencils.StencilGroup
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) -> None:
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assert section["Address"] >= len(group.code.body)
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assert "SectionData" in section
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flags = {flag["Name"] for flag in section["Attributes"]["Flags"]}
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name = section["Name"]["Value"]
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name = name.removeprefix(self.prefix)
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if "SomeInstructions" in flags:
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value = _stencils.HoleValue.CODE
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stencil = group.code
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start_address = 0
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group.symbols[name] = value, section["Address"] - start_address
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else:
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value = _stencils.HoleValue.DATA
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stencil = group.data
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start_address = len(group.code.body)
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group.symbols[name] = value, len(group.code.body)
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base = section["Address"] - start_address
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group.symbols[section["Index"]] = value, base
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stencil.body.extend(
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[0] * (section["Address"] - len(group.code.body) - len(group.data.body))
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)
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stencil.body.extend(section["SectionData"]["Bytes"])
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assert "Symbols" in section
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for wrapped_symbol in section["Symbols"]:
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symbol = wrapped_symbol["Symbol"]
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offset = symbol["Value"] - start_address
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name = symbol["Name"]["Value"]
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name = name.removeprefix(self.prefix)
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group.symbols[name] = value, offset
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assert "Relocations" in section
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for wrapped_relocation in section["Relocations"]:
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relocation = wrapped_relocation["Relocation"]
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hole = self._handle_relocation(base, relocation, stencil.body)
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stencil.holes.append(hole)
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def _handle_relocation(
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self, base: int, relocation: _schema.MachORelocation, raw: bytes
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) -> _stencils.Hole:
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symbol: str | None
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match relocation:
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case {
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"Offset": offset,
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"Symbol": {"Value": s},
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"Type": {
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"Value": "ARM64_RELOC_GOT_LOAD_PAGE21"
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| "ARM64_RELOC_GOT_LOAD_PAGEOFF12" as kind
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},
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}:
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offset += base
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s = s.removeprefix(self.prefix)
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value, symbol = _stencils.HoleValue.GOT, s
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addend = 0
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case {
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"Offset": offset,
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"Section": {"Value": s},
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"Type": {"Value": kind},
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} | {
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"Offset": offset,
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"Symbol": {"Value": s},
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"Type": {"Value": kind},
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}:
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offset += base
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s = s.removeprefix(self.prefix)
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value, symbol = _stencils.symbol_to_value(s)
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addend = 0
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case _:
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raise NotImplementedError(relocation)
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# Turn Clang's weird __bzero calls into normal bzero calls:
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if symbol == "__bzero":
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symbol = "bzero"
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return _stencils.Hole(offset, kind, value, symbol, addend)
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def get_target(host: str) -> _COFF | _ELF | _MachO:
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"""Build a _Target for the given host "triple" and options."""
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if re.fullmatch(r"aarch64-apple-darwin.*", host):
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return _MachO(host, alignment=8, prefix="_")
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if re.fullmatch(r"aarch64-.*-linux-gnu", host):
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return _ELF(host, alignment=8)
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if re.fullmatch(r"i686-pc-windows-msvc", host):
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return _COFF(host, prefix="_")
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if re.fullmatch(r"x86_64-apple-darwin.*", host):
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return _MachO(host, prefix="_")
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if re.fullmatch(r"x86_64-pc-windows-msvc", host):
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return _COFF(host)
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if re.fullmatch(r"x86_64-.*-linux-gnu", host):
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return _ELF(host)
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raise ValueError(host)
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