cpython/Tools/scripts/summarize_stats.py

"""Print a summary of specialization stats for all files in the
default stats folders.
"""

from __future__ import annotations

# NOTE: Bytecode introspection modules (opcode, dis, etc.) should only
# be imported when loading a single dataset. When comparing datasets, it
# could get it wrong, leading to subtle errors.

import argparse
import collections
from collections.abc import KeysView
from dataclasses import dataclass
from datetime import date
import enum
import functools
import itertools
import json
from operator import itemgetter
import os
from pathlib import Path
import re
import sys
import textwrap
from typing import Any, Callable, TextIO, TypeAlias


RawData: TypeAlias = dict[str, Any]
Rows: TypeAlias = list[tuple]
Columns: TypeAlias = tuple[str, ...]
RowCalculator: TypeAlias = Callable[["Stats"], Rows]


# TODO: Check for parity


if os.name == "nt":
    DEFAULT_DIR = "c:\\temp\\py_stats\\"
else:
    DEFAULT_DIR = "/tmp/py_stats/"


SOURCE_DIR = Path(__file__).parents[2]


TOTAL = "specialization.hit", "specialization.miss", "execution_count"


def pretty(name: str) -> str:
    return name.replace("_", " ").lower()


def _load_metadata_from_source():
    def get_defines(filepath: Path, prefix: str = "SPEC_FAIL"):
        with open(SOURCE_DIR / filepath) as spec_src:
            defines = collections.defaultdict(list)
            start = "#define " + prefix + "_"
            for line in spec_src:
                line = line.strip()
                if not line.startswith(start):
                    continue
                line = line[len(start) :]
                name, val = line.split()
                defines[int(val.strip())].append(name.strip())
        return defines

    import opcode

    return {
        "_specialized_instructions": [
            op for op in opcode._specialized_opmap.keys() if "__" not in op  # type: ignore
        ],
        "_stats_defines": get_defines(
            Path("Include") / "cpython" / "pystats.h", "EVAL_CALL"
        ),
        "_defines": get_defines(Path("Python") / "specialize.c"),
    }


def load_raw_data(input: Path) -> RawData:
    if input.is_file():
        with open(input, "r") as fd:
            data = json.load(fd)

        data["_stats_defines"] = {int(k): v for k, v in data["_stats_defines"].items()}
        data["_defines"] = {int(k): v for k, v in data["_defines"].items()}

        return data

    elif input.is_dir():
        stats = collections.Counter[str]()

        for filename in input.iterdir():
            with open(filename) as fd:
                for line in fd:
                    try:
                        key, value = line.split(":")
                    except ValueError:
                        print(
                            f"Unparsable line: '{line.strip()}' in {filename}",
                            file=sys.stderr,
                        )
                        continue
                    # Hack to handle older data files where some uops
                    # are missing an underscore prefix in their name
                    if key.startswith("uops[") and key[5:6] != "_":
                        key = "uops[_" + key[5:]
                    stats[key.strip()] += int(value)
            stats["__nfiles__"] += 1

        data = dict(stats)
        data.update(_load_metadata_from_source())
        return data

    else:
        raise ValueError(f"{input} is not a file or directory path")


def save_raw_data(data: RawData, json_output: TextIO):
    json.dump(data, json_output)


@dataclass(frozen=True)
class Doc:
    text: str
    doc: str

    def markdown(self) -> str:
        return textwrap.dedent(
            f"""
            {self.text}
            <details>
            <summary>ⓘ</summary>

            {self.doc}
            </details>
            """
        )


class Count(int):
    def markdown(self) -> str:
        return format(self, ",d")


@dataclass(frozen=True)
class Ratio:
    num: int
    den: int | None = None
    percentage: bool = True

    def __float__(self):
        if self.den == 0:
            return 0.0
        elif self.den is None:
            return self.num
        else:
            return self.num / self.den

    def markdown(self) -> str:
        if self.den is None:
            return ""
        elif self.den == 0:
            if self.num != 0:
                return f"{self.num:,} / 0 !!"
            return ""
        elif self.percentage:
            return f"{self.num / self.den:,.01%}"
        else:
            return f"{self.num / self.den:,.02f}"


class DiffRatio(Ratio):
    def __init__(self, base: int | str, head: int | str):
        if isinstance(base, str) or isinstance(head, str):
            super().__init__(0, 0)
        else:
            super().__init__(head - base, base)


class OpcodeStats:
    """
    Manages the data related to specific set of opcodes, e.g. tier1 (with prefix
    "opcode") or tier2 (with prefix "uops").
    """

    def __init__(self, data: dict[str, Any], defines, specialized_instructions):
        self._data = data
        self._defines = defines
        self._specialized_instructions = specialized_instructions

    def get_opcode_names(self) -> KeysView[str]:
        return self._data.keys()

    def get_pair_counts(self) -> dict[tuple[str, str], int]:
        pair_counts = {}
        for name_i, opcode_stat in self._data.items():
            for key, value in opcode_stat.items():
                if value and key.startswith("pair_count"):
                    name_j, _, _ = key[len("pair_count") + 1 :].partition("]")
                    pair_counts[(name_i, name_j)] = value
        return pair_counts

    def get_total_execution_count(self) -> int:
        return sum(x.get("execution_count", 0) for x in self._data.values())

    def get_execution_counts(self) -> dict[str, tuple[int, int]]:
        counts = {}
        for name, opcode_stat in self._data.items():
            if "execution_count" in opcode_stat:
                count = opcode_stat["execution_count"]
                miss = 0
                if "specializable" not in opcode_stat:
                    miss = opcode_stat.get("specialization.miss", 0)
                counts[name] = (count, miss)
        return counts

    @functools.cache
    def _get_pred_succ(
        self,
    ) -> tuple[dict[str, collections.Counter], dict[str, collections.Counter]]:
        pair_counts = self.get_pair_counts()

        predecessors: dict[str, collections.Counter] = collections.defaultdict(
            collections.Counter
        )
        successors: dict[str, collections.Counter] = collections.defaultdict(
            collections.Counter
        )
        for (first, second), count in pair_counts.items():
            if count:
                predecessors[second][first] = count
                successors[first][second] = count

        return predecessors, successors

    def get_predecessors(self, opcode: str) -> collections.Counter[str]:
        return self._get_pred_succ()[0][opcode]

    def get_successors(self, opcode: str) -> collections.Counter[str]:
        return self._get_pred_succ()[1][opcode]

    def _get_stats_for_opcode(self, opcode: str) -> dict[str, int]:
        return self._data[opcode]

    def get_specialization_total(self, opcode: str) -> int:
        family_stats = self._get_stats_for_opcode(opcode)
        return sum(family_stats.get(kind, 0) for kind in TOTAL)

    def get_specialization_counts(self, opcode: str) -> dict[str, int]:
        family_stats = self._get_stats_for_opcode(opcode)

        result = {}
        for key, value in sorted(family_stats.items()):
            if key.startswith("specialization."):
                label = key[len("specialization.") :]
                if label in ("success", "failure") or label.startswith("failure_kinds"):
                    continue
            elif key in (
                "execution_count",
                "specializable",
            ) or key.startswith("pair"):
                continue
            else:
                label = key
            result[label] = value

        return result

    def get_specialization_success_failure(self, opcode: str) -> dict[str, int]:
        family_stats = self._get_stats_for_opcode(opcode)
        result = {}
        for key in ("specialization.success", "specialization.failure"):
            label = key[len("specialization.") :]
            val = family_stats.get(key, 0)
            result[label] = val
        return result

    def get_specialization_failure_total(self, opcode: str) -> int:
        return self._get_stats_for_opcode(opcode).get("specialization.failure", 0)

    def get_specialization_failure_kinds(self, opcode: str) -> dict[str, int]:
        def kind_to_text(kind: int, opcode: str):
            if kind <= 8:
                return pretty(self._defines[kind][0])
            if opcode == "LOAD_SUPER_ATTR":
                opcode = "SUPER"
            elif opcode.endswith("ATTR"):
                opcode = "ATTR"
            elif opcode in ("FOR_ITER", "GET_ITER", "SEND"):
                opcode = "ITER"
            elif opcode.endswith("SUBSCR"):
                opcode = "SUBSCR"
            for name in self._defines[kind]:
                if name.startswith(opcode):
                    return pretty(name[len(opcode) + 1 :])
            return "kind " + str(kind)

        family_stats = self._get_stats_for_opcode(opcode)

        def key_to_index(key):
            return int(key[:-1].split("[")[1])

        max_index = 0
        for key in family_stats:
            if key.startswith("specialization.failure_kind"):
                max_index = max(max_index, key_to_index(key))

        failure_kinds = [0] * (max_index + 1)
        for key in family_stats:
            if not key.startswith("specialization.failure_kind"):
                continue
            failure_kinds[key_to_index(key)] = family_stats[key]
        return {
            kind_to_text(index, opcode): value
            for (index, value) in enumerate(failure_kinds)
            if value
        }

    def is_specializable(self, opcode: str) -> bool:
        return "specializable" in self._get_stats_for_opcode(opcode)

    def get_specialized_total_counts(self) -> tuple[int, int, int]:
        basic = 0
        specialized_hits = 0
        specialized_misses = 0
        not_specialized = 0
        for opcode, opcode_stat in self._data.items():
            if "execution_count" not in opcode_stat:
                continue
            count = opcode_stat["execution_count"]
            if "specializable" in opcode_stat:
                not_specialized += count
            elif opcode in self._specialized_instructions:
                miss = opcode_stat.get("specialization.miss", 0)
                specialized_hits += count - miss
                specialized_misses += miss
            else:
                basic += count
        return basic, specialized_hits, specialized_misses, not_specialized

    def get_deferred_counts(self) -> dict[str, int]:
        return {
            opcode: opcode_stat.get("specialization.deferred", 0)
            for opcode, opcode_stat in self._data.items()
            if opcode != "RESUME"
        }

    def get_misses_counts(self) -> dict[str, int]:
        return {
            opcode: opcode_stat.get("specialization.miss", 0)
            for opcode, opcode_stat in self._data.items()
            if not self.is_specializable(opcode)
        }

    def get_opcode_counts(self) -> dict[str, int]:
        counts = {}
        for opcode, entry in self._data.items():
            count = entry.get("count", 0)
            if count:
                counts[opcode] = count
        return counts


class Stats:
    def __init__(self, data: RawData):
        self._data = data

    def get(self, key: str) -> int:
        return self._data.get(key, 0)

    @functools.cache
    def get_opcode_stats(self, prefix: str) -> OpcodeStats:
        opcode_stats = collections.defaultdict[str, dict](dict)
        for key, value in self._data.items():
            if not key.startswith(prefix):
                continue
            name, _, rest = key[len(prefix) + 1 :].partition("]")
            opcode_stats[name][rest.strip(".")] = value
        return OpcodeStats(
            opcode_stats,
            self._data["_defines"],
            self._data["_specialized_instructions"],
        )

    def get_call_stats(self) -> dict[str, int]:
        defines = self._data["_stats_defines"]
        result = {}
        for key, value in sorted(self._data.items()):
            if "Calls to" in key:
                result[key] = value
            elif key.startswith("Calls "):
                name, index = key[:-1].split("[")
                label = f"{name} ({pretty(defines[int(index)][0])})"
                result[label] = value

        for key, value in sorted(self._data.items()):
            if key.startswith("Frame"):
                result[key] = value

        return result

    def get_object_stats(self) -> dict[str, tuple[int, int]]:
        total_materializations = self._data.get("Object inline values", 0)
        total_allocations = self._data.get("Object allocations", 0) + self._data.get(
            "Object allocations from freelist", 0
        )
        total_increfs = (
            self._data.get("Object interpreter mortal increfs", 0) +
            self._data.get("Object mortal increfs", 0) +
            self._data.get("Object interpreter immortal increfs", 0) +
            self._data.get("Object immortal increfs", 0)
        )
        total_decrefs = (
            self._data.get("Object interpreter mortal decrefs", 0) +
            self._data.get("Object mortal decrefs", 0) +
            self._data.get("Object interpreter immortal decrefs", 0) +
            self._data.get("Object immortal decrefs", 0)
        )

        result = {}
        for key, value in self._data.items():
            if key.startswith("Object"):
                if "materialize" in key:
                    den = total_materializations
                elif "allocations" in key:
                    den = total_allocations
                elif "increfs" in key:
                    den = total_increfs
                elif "decrefs" in key:
                    den = total_decrefs
                else:
                    den = None
                label = key[6:].strip()
                label = label[0].upper() + label[1:]
                result[label] = (value, den)
        return result

    def get_gc_stats(self) -> list[dict[str, int]]:
        gc_stats: list[dict[str, int]] = []
        for key, value in self._data.items():
            if not key.startswith("GC"):
                continue
            n, _, rest = key[3:].partition("]")
            name = rest.strip()
            gen_n = int(n)
            while len(gc_stats) <= gen_n:
                gc_stats.append({})
            gc_stats[gen_n][name] = value
        return gc_stats

    def get_optimization_stats(self) -> dict[str, tuple[int, int | None]]:
        if "Optimization attempts" not in self._data:
            return {}

        attempts = self._data["Optimization attempts"]
        created = self._data["Optimization traces created"]
        executed = self._data["Optimization traces executed"]
        uops = self._data["Optimization uops executed"]
        trace_stack_overflow = self._data["Optimization trace stack overflow"]
        trace_stack_underflow = self._data["Optimization trace stack underflow"]
        trace_too_long = self._data["Optimization trace too long"]
        trace_too_short = self._data["Optimization trace too short"]
        inner_loop = self._data["Optimization inner loop"]
        recursive_call = self._data["Optimization recursive call"]
        low_confidence = self._data["Optimization low confidence"]
        unknown_callee = self._data["Optimization unknown callee"]
        executors_invalidated = self._data["Executors invalidated"]

        return {
            Doc(
                "Optimization attempts",
                "The number of times a potential trace is identified.  Specifically, this "
                "occurs in the JUMP BACKWARD instruction when the counter reaches a "
                "threshold.",
            ): (attempts, None),
            Doc(
                "Traces created", "The number of traces that were successfully created."
            ): (created, attempts),
            Doc(
                "Trace stack overflow",
                "A trace is truncated because it would require more than 5 stack frames.",
            ): (trace_stack_overflow, attempts),
            Doc(
                "Trace stack underflow",
                "A potential trace is abandoned because it pops more frames than it pushes.",
            ): (trace_stack_underflow, attempts),
            Doc(
                "Trace too long",
                "A trace is truncated because it is longer than the instruction buffer.",
            ): (trace_too_long, attempts),
            Doc(
                "Trace too short",
                "A potential trace is abandoned because it is too short.",
            ): (trace_too_short, attempts),
            Doc(
                "Inner loop found", "A trace is truncated because it has an inner loop"
            ): (inner_loop, attempts),
            Doc(
                "Recursive call",
                "A trace is truncated because it has a recursive call.",
            ): (recursive_call, attempts),
            Doc(
                "Low confidence",
                "A trace is abandoned because the likelihood of the jump to top being taken "
                "is too low.",
            ): (low_confidence, attempts),
            Doc(
                "Unknown callee",
                "A trace is abandoned because the target of a call is unknown.",
            ): (unknown_callee, attempts),
            Doc(
                "Executors invalidated",
                "The number of executors that were invalidated due to watched "
                "dictionary changes.",
            ): (executors_invalidated, created),
            Doc("Traces executed", "The number of traces that were executed"): (
                executed,
                None,
            ),
            Doc(
                "Uops executed",
                "The total number of uops (micro-operations) that were executed",
            ): (
                uops,
                executed,
            ),
        }

    def get_optimizer_stats(self) -> dict[str, tuple[int, int | None]]:
        attempts = self._data["Optimization optimizer attempts"]
        successes = self._data["Optimization optimizer successes"]
        no_memory = self._data["Optimization optimizer failure no memory"]
        builtins_changed = self._data["Optimizer remove globals builtins changed"]
        incorrect_keys = self._data["Optimizer remove globals incorrect keys"]

        return {
            Doc(
                "Optimizer attempts",
                "The number of times the trace optimizer (_Py_uop_analyze_and_optimize) was run.",
            ): (attempts, None),
            Doc(
                "Optimizer successes",
                "The number of traces that were successfully optimized.",
            ): (successes, attempts),
            Doc(
                "Optimizer no memory",
                "The number of optimizations that failed due to no memory.",
            ): (no_memory, attempts),
            Doc(
                "Remove globals builtins changed",
                "The builtins changed during optimization",
            ): (builtins_changed, attempts),
            Doc(
                "Remove globals incorrect keys",
                "The keys in the globals dictionary aren't what was expected",
            ): (incorrect_keys, attempts),
        }

    def get_jit_memory_stats(self) -> dict[Doc, tuple[int, int | None]]:
        jit_total_memory_size = self._data["JIT total memory size"]
        jit_code_size = self._data["JIT code size"]
        jit_trampoline_size = self._data["JIT trampoline size"]
        jit_data_size = self._data["JIT data size"]
        jit_padding_size = self._data["JIT padding size"]
        jit_freed_memory_size = self._data["JIT freed memory size"]

        return {
            Doc(
                "Total memory size",
                "The total size of the memory allocated for the JIT traces",
            ): (jit_total_memory_size, None),
            Doc(
                "Code size",
                "The size of the memory allocated for the code of the JIT traces",
            ): (jit_code_size, jit_total_memory_size),
            Doc(
                "Trampoline size",
                "The size of the memory allocated for the trampolines of the JIT traces",
            ): (jit_trampoline_size, jit_total_memory_size),
            Doc(
                "Data size",
                "The size of the memory allocated for the data of the JIT traces",
            ): (jit_data_size, jit_total_memory_size),
            Doc(
                "Padding size",
                "The size of the memory allocated for the padding of the JIT traces",
            ): (jit_padding_size, jit_total_memory_size),
            Doc(
                "Freed memory size",
                "The size of the memory freed from the JIT traces",
            ): (jit_freed_memory_size, jit_total_memory_size),
        }

    def get_histogram(self, prefix: str) -> list[tuple[int, int]]:
        rows = []
        for k, v in self._data.items():
            match = re.match(f"{prefix}\\[([0-9]+)\\]", k)
            if match is not None:
                entry = int(match.groups()[0])
                rows.append((entry, v))
        rows.sort()
        return rows

    def get_rare_events(self) -> list[tuple[str, int]]:
        prefix = "Rare event "
        return [
            (key[len(prefix) + 1 : -1].replace("_", " "), val)
            for key, val in self._data.items()
            if key.startswith(prefix)
        ]


class JoinMode(enum.Enum):
    # Join using the first column as a key
    SIMPLE = 0
    # Join using the first column as a key, and indicate the change in the
    # second column of each input table as a new column
    CHANGE = 1
    # Join using the first column as a key, indicating the change in the second
    # column of each input table as a new column, and omit all other columns
    CHANGE_ONE_COLUMN = 2
    # Join using the first column as a key, and indicate the change as a new
    # column, but don't sort by the amount of change.
    CHANGE_NO_SORT = 3


class Table:
    """
    A Table defines how to convert a set of Stats into a specific set of rows
    displaying some aspect of the data.
    """

    def __init__(
        self,
        column_names: Columns,
        calc_rows: RowCalculator,
        join_mode: JoinMode = JoinMode.SIMPLE,
    ):
        self.columns = column_names
        self.calc_rows = calc_rows
        self.join_mode = join_mode

    def join_row(self, key: str, row_a: tuple, row_b: tuple) -> tuple:
        match self.join_mode:
            case JoinMode.SIMPLE:
                return (key, *row_a, *row_b)
            case JoinMode.CHANGE | JoinMode.CHANGE_NO_SORT:
                return (key, *row_a, *row_b, DiffRatio(row_a[0], row_b[0]))
            case JoinMode.CHANGE_ONE_COLUMN:
                return (key, row_a[0], row_b[0], DiffRatio(row_a[0], row_b[0]))

    def join_columns(self, columns: Columns) -> Columns:
        match self.join_mode:
            case JoinMode.SIMPLE:
                return (
                    columns[0],
                    *("Base " + x for x in columns[1:]),
                    *("Head " + x for x in columns[1:]),
                )
            case JoinMode.CHANGE | JoinMode.CHANGE_NO_SORT:
                return (
                    columns[0],
                    *("Base " + x for x in columns[1:]),
                    *("Head " + x for x in columns[1:]),
                ) + ("Change:",)
            case JoinMode.CHANGE_ONE_COLUMN:
                return (
                    columns[0],
                    "Base " + columns[1],
                    "Head " + columns[1],
                    "Change:",
                )

    def join_tables(self, rows_a: Rows, rows_b: Rows) -> tuple[Columns, Rows]:
        ncols = len(self.columns)

        default = ("",) * (ncols - 1)
        data_a = {x[0]: x[1:] for x in rows_a}
        data_b = {x[0]: x[1:] for x in rows_b}

        if len(data_a) != len(rows_a) or len(data_b) != len(rows_b):
            raise ValueError("Duplicate keys")

        # To preserve ordering, use A's keys as is and then add any in B that
        # aren't in A
        keys = list(data_a.keys()) + [k for k in data_b.keys() if k not in data_a]
        rows = [
            self.join_row(k, data_a.get(k, default), data_b.get(k, default))
            for k in keys
        ]
        if self.join_mode in (JoinMode.CHANGE, JoinMode.CHANGE_ONE_COLUMN):
            rows.sort(key=lambda row: abs(float(row[-1])), reverse=True)

        columns = self.join_columns(self.columns)
        return columns, rows

    def get_table(
        self, base_stats: Stats, head_stats: Stats | None = None
    ) -> tuple[Columns, Rows]:
        if head_stats is None:
            rows = self.calc_rows(base_stats)
            return self.columns, rows
        else:
            rows_a = self.calc_rows(base_stats)
            rows_b = self.calc_rows(head_stats)
            cols, rows = self.join_tables(rows_a, rows_b)
            return cols, rows


class Section:
    """
    A Section defines a section of the output document.
    """

    def __init__(
        self,
        title: str = "",
        summary: str = "",
        part_iter=None,
        *,
        comparative: bool = True,
        doc: str = "",
    ):
        self.title = title
        if not summary:
            self.summary = title.lower()
        else:
            self.summary = summary
        self.doc = textwrap.dedent(doc)
        if part_iter is None:
            part_iter = []
        if isinstance(part_iter, list):

            def iter_parts(base_stats: Stats, head_stats: Stats | None):
                yield from part_iter

            self.part_iter = iter_parts
        else:
            self.part_iter = part_iter
        self.comparative = comparative


def calc_execution_count_table(prefix: str) -> RowCalculator:
    def calc(stats: Stats) -> Rows:
        opcode_stats = stats.get_opcode_stats(prefix)
        counts = opcode_stats.get_execution_counts()
        total = opcode_stats.get_total_execution_count()
        cumulative = 0
        rows: Rows = []
        for opcode, (count, miss) in sorted(
            counts.items(), key=itemgetter(1), reverse=True
        ):
            cumulative += count
            if miss:
                miss_val = Ratio(miss, count)
            else:
                miss_val = None
            rows.append(
                (
                    opcode,
                    Count(count),
                    Ratio(count, total),
                    Ratio(cumulative, total),
                    miss_val,
                )
            )
        return rows

    return calc


def execution_count_section() -> Section:
    return Section(
        "Execution counts",
        "Execution counts for Tier 1 instructions.",
        [
            Table(
                ("Name", "Count:", "Self:", "Cumulative:", "Miss ratio:"),
                calc_execution_count_table("opcode"),
                join_mode=JoinMode.CHANGE_ONE_COLUMN,
            )
        ],
        doc="""
        The "miss ratio" column shows the percentage of times the instruction
        executed that it deoptimized. When this happens, the base unspecialized
        instruction is not counted.
        """,
    )


def pair_count_section(prefix: str, title=None) -> Section:
    def calc_pair_count_table(stats: Stats) -> Rows:
        opcode_stats = stats.get_opcode_stats(prefix)
        pair_counts = opcode_stats.get_pair_counts()
        total = opcode_stats.get_total_execution_count()

        cumulative = 0
        rows: Rows = []
        for (opcode_i, opcode_j), count in itertools.islice(
            sorted(pair_counts.items(), key=itemgetter(1), reverse=True), 100
        ):
            cumulative += count
            rows.append(
                (
                    f"{opcode_i} {opcode_j}",
                    Count(count),
                    Ratio(count, total),
                    Ratio(cumulative, total),
                )
            )
        return rows

    return Section(
        "Pair counts",
        f"Pair counts for top 100 {title if title else prefix} pairs",
        [
            Table(
                ("Pair", "Count:", "Self:", "Cumulative:"),
                calc_pair_count_table,
            )
        ],
        comparative=False,
        doc="""
        Pairs of specialized operations that deoptimize and are then followed by
        the corresponding unspecialized instruction are not counted as pairs.
        """,
    )


def pre_succ_pairs_section() -> Section:
    def iter_pre_succ_pairs_tables(base_stats: Stats, head_stats: Stats | None = None):
        assert head_stats is None

        opcode_stats = base_stats.get_opcode_stats("opcode")

        for opcode in opcode_stats.get_opcode_names():
            predecessors = opcode_stats.get_predecessors(opcode)
            successors = opcode_stats.get_successors(opcode)
            predecessors_total = predecessors.total()
            successors_total = successors.total()
            if predecessors_total == 0 and successors_total == 0:
                continue
            pred_rows = [
                (pred, Count(count), Ratio(count, predecessors_total))
                for (pred, count) in predecessors.most_common(5)
            ]
            succ_rows = [
                (succ, Count(count), Ratio(count, successors_total))
                for (succ, count) in successors.most_common(5)
            ]

            yield Section(
                opcode,
                f"Successors and predecessors for {opcode}",
                [
                    Table(
                        ("Predecessors", "Count:", "Percentage:"),
                        lambda *_: pred_rows,  # type: ignore
                    ),
                    Table(
                        ("Successors", "Count:", "Percentage:"),
                        lambda *_: succ_rows,  # type: ignore
                    ),
                ],
            )

    return Section(
        "Predecessor/Successor Pairs",
        "Top 5 predecessors and successors of each Tier 1 opcode.",
        iter_pre_succ_pairs_tables,
        comparative=False,
        doc="""
        This does not include the unspecialized instructions that occur after a
        specialized instruction deoptimizes.
        """,
    )


def specialization_section() -> Section:
    def calc_specialization_table(opcode: str) -> RowCalculator:
        def calc(stats: Stats) -> Rows:
            DOCS = {
                "deferred": 'Lists the number of "deferred" (i.e. not specialized) instructions executed.',
                "hit": "Specialized instructions that complete.",
                "miss": "Specialized instructions that deopt.",
                "deopt": "Specialized instructions that deopt.",
            }

            opcode_stats = stats.get_opcode_stats("opcode")
            total = opcode_stats.get_specialization_total(opcode)
            specialization_counts = opcode_stats.get_specialization_counts(opcode)

            return [
                (
                    Doc(label, DOCS[label]),
                    Count(count),
                    Ratio(count, total),
                )
                for label, count in specialization_counts.items()
            ]

        return calc

    def calc_specialization_success_failure_table(name: str) -> RowCalculator:
        def calc(stats: Stats) -> Rows:
            values = stats.get_opcode_stats(
                "opcode"
            ).get_specialization_success_failure(name)
            total = sum(values.values())
            if total:
                return [
                    (label.capitalize(), Count(val), Ratio(val, total))
                    for label, val in values.items()
                ]
            else:
                return []

        return calc

    def calc_specialization_failure_kind_table(name: str) -> RowCalculator:
        def calc(stats: Stats) -> Rows:
            opcode_stats = stats.get_opcode_stats("opcode")
            failures = opcode_stats.get_specialization_failure_kinds(name)
            total = opcode_stats.get_specialization_failure_total(name)

            return sorted(
                [
                    (label, Count(value), Ratio(value, total))
                    for label, value in failures.items()
                    if value
                ],
                key=itemgetter(1),
                reverse=True,
            )

        return calc

    def iter_specialization_tables(base_stats: Stats, head_stats: Stats | None = None):
        opcode_base_stats = base_stats.get_opcode_stats("opcode")
        names = opcode_base_stats.get_opcode_names()
        if head_stats is not None:
            opcode_head_stats = head_stats.get_opcode_stats("opcode")
            names &= opcode_head_stats.get_opcode_names()  # type: ignore
        else:
            opcode_head_stats = None

        for opcode in sorted(names):
            if not opcode_base_stats.is_specializable(opcode):
                continue
            if opcode_base_stats.get_specialization_total(opcode) == 0 and (
                opcode_head_stats is None
                or opcode_head_stats.get_specialization_total(opcode) == 0
            ):
                continue
            yield Section(
                opcode,
                f"specialization stats for {opcode} family",
                [
                    Table(
                        ("Kind", "Count:", "Ratio:"),
                        calc_specialization_table(opcode),
                        JoinMode.CHANGE,
                    ),
                    Table(
                        ("Success", "Count:", "Ratio:"),
                        calc_specialization_success_failure_table(opcode),
                        JoinMode.CHANGE,
                    ),
                    Table(
                        ("Failure kind", "Count:", "Ratio:"),
                        calc_specialization_failure_kind_table(opcode),
                        JoinMode.CHANGE,
                    ),
                ],
            )

    return Section(
        "Specialization stats",
        "Specialization stats by family",
        iter_specialization_tables,
    )


def specialization_effectiveness_section() -> Section:
    def calc_specialization_effectiveness_table(stats: Stats) -> Rows:
        opcode_stats = stats.get_opcode_stats("opcode")
        total = opcode_stats.get_total_execution_count()

        (
            basic,
            specialized_hits,
            specialized_misses,
            not_specialized,
        ) = opcode_stats.get_specialized_total_counts()

        return [
            (
                Doc(
                    "Basic",
                    "Instructions that are not and cannot be specialized, e.g. `LOAD_FAST`.",
                ),
                Count(basic),
                Ratio(basic, total),
            ),
            (
                Doc(
                    "Not specialized",
                    "Instructions that could be specialized but aren't, e.g. `LOAD_ATTR`, `BINARY_SLICE`.",
                ),
                Count(not_specialized),
                Ratio(not_specialized, total),
            ),
            (
                Doc(
                    "Specialized hits",
                    "Specialized instructions, e.g. `LOAD_ATTR_MODULE` that complete.",
                ),
                Count(specialized_hits),
                Ratio(specialized_hits, total),
            ),
            (
                Doc(
                    "Specialized misses",
                    "Specialized instructions, e.g. `LOAD_ATTR_MODULE` that deopt.",
                ),
                Count(specialized_misses),
                Ratio(specialized_misses, total),
            ),
        ]

    def calc_deferred_by_table(stats: Stats) -> Rows:
        opcode_stats = stats.get_opcode_stats("opcode")
        deferred_counts = opcode_stats.get_deferred_counts()
        total = sum(deferred_counts.values())
        if total == 0:
            return []

        return [
            (name, Count(value), Ratio(value, total))
            for name, value in sorted(
                deferred_counts.items(), key=itemgetter(1), reverse=True
            )[:10]
        ]

    def calc_misses_by_table(stats: Stats) -> Rows:
        opcode_stats = stats.get_opcode_stats("opcode")
        misses_counts = opcode_stats.get_misses_counts()
        total = sum(misses_counts.values())
        if total == 0:
            return []

        return [
            (name, Count(value), Ratio(value, total))
            for name, value in sorted(
                misses_counts.items(), key=itemgetter(1), reverse=True
            )[:10]
        ]

    return Section(
        "Specialization effectiveness",
        "",
        [
            Table(
                ("Instructions", "Count:", "Ratio:"),
                calc_specialization_effectiveness_table,
                JoinMode.CHANGE,
            ),
            Section(
                "Deferred by instruction",
                "Breakdown of deferred (not specialized) instruction counts by family",
                [
                    Table(
                        ("Name", "Count:", "Ratio:"),
                        calc_deferred_by_table,
                        JoinMode.CHANGE,
                    )
                ],
            ),
            Section(
                "Misses by instruction",
                "Breakdown of misses (specialized deopts) instruction counts by family",
                [
                    Table(
                        ("Name", "Count:", "Ratio:"),
                        calc_misses_by_table,
                        JoinMode.CHANGE,
                    )
                ],
            ),
        ],
        doc="""
        All entries are execution counts. Should add up to the total number of
        Tier 1 instructions executed.
        """,
    )


def call_stats_section() -> Section:
    def calc_call_stats_table(stats: Stats) -> Rows:
        call_stats = stats.get_call_stats()
        total = sum(v for k, v in call_stats.items() if "Calls to" in k)
        return [
            (key, Count(value), Ratio(value, total))
            for key, value in call_stats.items()
        ]

    return Section(
        "Call stats",
        "Inlined calls and frame stats",
        [
            Table(
                ("", "Count:", "Ratio:"),
                calc_call_stats_table,
                JoinMode.CHANGE,
            )
        ],
        doc="""
        This shows what fraction of calls to Python functions are inlined (i.e.
        not having a call at the C level) and for those that are not, where the
        call comes from.  The various categories overlap.

        Also includes the count of frame objects created.
        """,
    )


def object_stats_section() -> Section:
    def calc_object_stats_table(stats: Stats) -> Rows:
        object_stats = stats.get_object_stats()
        return [
            (label, Count(value), Ratio(value, den))
            for label, (value, den) in object_stats.items()
        ]

    return Section(
        "Object stats",
        "Allocations, frees and dict materializatons",
        [
            Table(
                ("", "Count:", "Ratio:"),
                calc_object_stats_table,
                JoinMode.CHANGE,
            )
        ],
        doc="""
        Below, "allocations" means "allocations that are not from a freelist".
        Total allocations = "Allocations from freelist" + "Allocations".

        "Inline values" is the number of values arrays inlined into objects.

        The cache hit/miss numbers are for the MRO cache, split into dunder and
        other names.
        """,
    )


def gc_stats_section() -> Section:
    def calc_gc_stats(stats: Stats) -> Rows:
        gc_stats = stats.get_gc_stats()

        return [
            (
                Count(i),
                Count(gen["collections"]),
                Count(gen["objects collected"]),
                Count(gen["object visits"]),
                Count(gen["objects reachable from roots"]),
                Count(gen["objects not reachable from roots"]),
            )
            for (i, gen) in enumerate(gc_stats)
        ]

    return Section(
        "GC stats",
        "GC collections and effectiveness",
        [
            Table(
                ("Generation:", "Collections:", "Objects collected:", "Object visits:",
                 "Reachable from roots:", "Not reachable from roots:"),
                calc_gc_stats,
            )
        ],
        doc="""
        Collected/visits gives some measure of efficiency.
        """,
    )


def optimization_section() -> Section:
    def calc_optimization_table(stats: Stats) -> Rows:
        optimization_stats = stats.get_optimization_stats()

        return [
            (
                label,
                Count(value),
                Ratio(value, den, percentage=label != "Uops executed"),
            )
            for label, (value, den) in optimization_stats.items()
        ]

    def calc_optimizer_table(stats: Stats) -> Rows:
        optimizer_stats = stats.get_optimizer_stats()

        return [
            (label, Count(value), Ratio(value, den))
            for label, (value, den) in optimizer_stats.items()
        ]

    def calc_jit_memory_table(stats: Stats) -> Rows:
        jit_memory_stats = stats.get_jit_memory_stats()

        return [
            (
                label,
                Count(value),
                Ratio(value, den, percentage=label != "Total memory size"),
            )
            for label, (value, den) in jit_memory_stats.items()
        ]

    def calc_histogram_table(key: str, den: str | None = None) -> RowCalculator:
        def calc(stats: Stats) -> Rows:
            histogram = stats.get_histogram(key)

            if den:
                denominator = stats.get(den)
            else:
                denominator = 0
                for _, v in histogram:
                    denominator += v

            rows: Rows = []
            for k, v in histogram:
                rows.append(
                    (
                        f"<= {k:,d}",
                        Count(v),
                        Ratio(v, denominator),
                    )
                )
            # Don't include any leading and trailing zero entries
            start = 0
            end = len(rows) - 1

            while start <= end:
                if rows[start][1] == 0:
                    start += 1
                elif rows[end][1] == 0:
                    end -= 1
                else:
                    break

            return rows[start:end+1]

        return calc

    def calc_unsupported_opcodes_table(stats: Stats) -> Rows:
        unsupported_opcodes = stats.get_opcode_stats("unsupported_opcode")
        return sorted(
            [
                (opcode, Count(count))
                for opcode, count in unsupported_opcodes.get_opcode_counts().items()
            ],
            key=itemgetter(1),
            reverse=True,
        )

    def calc_error_in_opcodes_table(stats: Stats) -> Rows:
        error_in_opcodes = stats.get_opcode_stats("error_in_opcode")
        return sorted(
            [
                (opcode, Count(count))
                for opcode, count in error_in_opcodes.get_opcode_counts().items()
            ],
            key=itemgetter(1),
            reverse=True,
        )

    def iter_optimization_tables(base_stats: Stats, head_stats: Stats | None = None):
        if not base_stats.get_optimization_stats() or (
            head_stats is not None and not head_stats.get_optimization_stats()
        ):
            return

        yield Table(("", "Count:", "Ratio:"), calc_optimization_table, JoinMode.CHANGE)
        yield Table(("", "Count:", "Ratio:"), calc_optimizer_table, JoinMode.CHANGE)
        yield Section(
            "JIT memory stats",
            "JIT memory stats",
            [
                Table(
                    ("", "Size (bytes):", "Ratio:"),
                    calc_jit_memory_table,
                    JoinMode.CHANGE
                )
            ],
        )
        yield Section(
            "JIT trace total memory histogram",
            "JIT trace total memory histogram",
            [
                Table(
                    ("Size (bytes)", "Count", "Ratio:"),
                    calc_histogram_table("Trace total memory size"),
                    JoinMode.CHANGE_NO_SORT,
                )
            ],
        )
        for name, den in [
            ("Trace length", "Optimization traces created"),
            ("Optimized trace length", "Optimization traces created"),
            ("Trace run length", "Optimization traces executed"),
        ]:
            yield Section(
                f"{name} histogram",
                "",
                [
                    Table(
                        ("Range", "Count:", "Ratio:"),
                        calc_histogram_table(name, den),
                        JoinMode.CHANGE_NO_SORT,
                    )
                ],
            )
        yield Section(
            "Uop execution stats",
            "",
            [
                Table(
                    ("Name", "Count:", "Self:", "Cumulative:", "Miss ratio:"),
                    calc_execution_count_table("uops"),
                    JoinMode.CHANGE_ONE_COLUMN,
                )
            ],
        )
        yield pair_count_section(prefix="uop", title="Non-JIT uop")
        yield Section(
            "Unsupported opcodes",
            "",
            [
                Table(
                    ("Opcode", "Count:"),
                    calc_unsupported_opcodes_table,
                    JoinMode.CHANGE,
                )
            ],
        )
        yield Section(
            "Optimizer errored out with opcode",
            "Optimization stopped after encountering this opcode",
            [Table(("Opcode", "Count:"), calc_error_in_opcodes_table, JoinMode.CHANGE)],
        )

    return Section(
        "Optimization (Tier 2) stats",
        "statistics about the Tier 2 optimizer",
        iter_optimization_tables,
    )


def rare_event_section() -> Section:
    def calc_rare_event_table(stats: Stats) -> Table:
        DOCS = {
            "set class": "Setting an object's class, `obj.__class__ = ...`",
            "set bases": "Setting the bases of a class, `cls.__bases__ = ...`",
            "set eval frame func": (
                "Setting the PEP 523 frame eval function "
                "`_PyInterpreterState_SetFrameEvalFunc()`"
            ),
            "builtin dict": "Modifying the builtins, `__builtins__.__dict__[var] = ...`",
            "func modification": "Modifying a function, e.g. `func.__defaults__ = ...`, etc.",
            "watched dict modification": "A watched dict has been modified",
            "watched globals modification": "A watched `globals()` dict has been modified",
        }
        return [(Doc(x, DOCS[x]), Count(y)) for x, y in stats.get_rare_events()]

    return Section(
        "Rare events",
        "Counts of rare/unlikely events",
        [Table(("Event", "Count:"), calc_rare_event_table, JoinMode.CHANGE)],
    )


def meta_stats_section() -> Section:
    def calc_rows(stats: Stats) -> Rows:
        return [("Number of data files", Count(stats.get("__nfiles__")))]

    return Section(
        "Meta stats",
        "Meta statistics",
        [Table(("", "Count:"), calc_rows, JoinMode.CHANGE)],
    )


LAYOUT = [
    execution_count_section(),
    pair_count_section("opcode"),
    pre_succ_pairs_section(),
    specialization_section(),
    specialization_effectiveness_section(),
    call_stats_section(),
    object_stats_section(),
    gc_stats_section(),
    optimization_section(),
    rare_event_section(),
    meta_stats_section(),
]


def output_markdown(
    out: TextIO,
    obj: Section | Table | list,
    base_stats: Stats,
    head_stats: Stats | None = None,
    level: int = 2,
) -> None:
    def to_markdown(x):
        if hasattr(x, "markdown"):
            return x.markdown()
        elif isinstance(x, str):
            return x
        elif x is None:
            return ""
        else:
            raise TypeError(f"Can't convert {x} to markdown")

    match obj:
        case Section():
            if obj.title:
                print("#" * level, obj.title, file=out)
                print(file=out)
                print("<details>", file=out)
                print("<summary>", obj.summary, "</summary>", file=out)
                print(file=out)
            if obj.doc:
                print(obj.doc, file=out)

            if head_stats is not None and obj.comparative is False:
                print("Not included in comparative output.\n")
            else:
                for part in obj.part_iter(base_stats, head_stats):
                    output_markdown(out, part, base_stats, head_stats, level=level + 1)
            print(file=out)
            if obj.title:
                print("</details>", file=out)
                print(file=out)

        case Table():
            header, rows = obj.get_table(base_stats, head_stats)
            if len(rows) == 0:
                return

            alignments = []
            for item in header:
                if item.endswith(":"):
                    alignments.append("right")
                else:
                    alignments.append("left")

            print("<table>", file=out)
            print("<thead>", file=out)
            print("<tr>", file=out)
            for item, align in zip(header, alignments):
                if item.endswith(":"):
                    item = item[:-1]
                print(f'<th align="{align}">{item}</th>', file=out)
            print("</tr>", file=out)
            print("</thead>", file=out)

            print("<tbody>", file=out)
            for row in rows:
                if len(row) != len(header):
                    raise ValueError(
                        "Wrong number of elements in row '" + str(row) + "'"
                    )
                print("<tr>", file=out)
                for col, align in zip(row, alignments):
                    print(f'<td align="{align}">{to_markdown(col)}</td>', file=out)
                print("</tr>", file=out)
            print("</tbody>", file=out)

            print("</table>", file=out)
            print(file=out)

        case list():
            for part in obj:
                output_markdown(out, part, base_stats, head_stats, level=level)

            print("---", file=out)
            print("Stats gathered on:", date.today(), file=out)


def output_stats(inputs: list[Path], json_output=str | None):
    match len(inputs):
        case 1:
            data = load_raw_data(Path(inputs[0]))
            if json_output is not None:
                with open(json_output, "w", encoding="utf-8") as f:
                    save_raw_data(data, f)  # type: ignore
            stats = Stats(data)
            output_markdown(sys.stdout, LAYOUT, stats)
        case 2:
            if json_output is not None:
                raise ValueError(
                    "Can not output to JSON when there are multiple inputs"
                )
            base_data = load_raw_data(Path(inputs[0]))
            head_data = load_raw_data(Path(inputs[1]))
            base_stats = Stats(base_data)
            head_stats = Stats(head_data)
            output_markdown(sys.stdout, LAYOUT, base_stats, head_stats)


def main():
    parser = argparse.ArgumentParser(description="Summarize pystats results")

    parser.add_argument(
        "inputs",
        nargs="*",
        type=str,
        default=[DEFAULT_DIR],
        help=f"""
        Input source(s).
        For each entry, if a .json file, the output provided by --json-output from a previous run;
        if a directory, a directory containing raw pystats .txt files.
        If one source is provided, its stats are printed.
        If two sources are provided, comparative stats are printed.
        Default is {DEFAULT_DIR}.
        """,
    )

    parser.add_argument(
        "--json-output",
        nargs="?",
        help="Output complete raw results to the given JSON file.",
    )

    args = parser.parse_args()

    if len(args.inputs) > 2:
        raise ValueError("0-2 arguments may be provided.")

    output_stats(args.inputs, json_output=args.json_output)


if __name__ == "__main__":
    main()