fzakaria

// SPDX-License-Identifier: GPL-2.0
/*
 * binfmt_misc 'B' (BPF) program: match aarch64 ELF binaries and choose the
 * interpreter (qemu-aarch64) dynamically via bpf_binprm_set_interp().
 *
 * The program is given the BINPRM_BUF_SIZE file header as context. It inspects
 * the ELF header and, on a match, sets the interpreter and returns 1. This
 * makes the handler a superset of a traditional magic rule: the program both
 * decides the match and computes the interpreter path (it could equally derive
 * a path relative to the binary).

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package main

import (
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"strings"
)

fzakaria

Cache-Aware Struct Benchmarks

Benchmarks demonstrating how struct size and memory layout affect performance due to CPU cache behavior. Companion code for the blog post Every byte matters.

Benchmarks

1. Pointer-Chasing (cache staircase)

fzakaria

ClassPathInfo = provider(
    "Provider for classpath information",
    fields = {
        "compile_jars": "A json fragment containing the mapping of the current jar to its source jar",
    },
)

def _classpath_aspect_impl(target, ctx):
    java_info = target[JavaInfo]
    compile_jars = depset(

fzakaria

"""
FlatBuffer Java rule for Bazel
"""

FlatbufferInfo = provider(
    doc = "A provider for FlatBuffer schema files.",
    fields = {
        "fbs_files": "The list of fbs files that were used as inputs",
    },
)

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genrule(
    name = "check_cgroup",
    outs = ["cgroup_output.txt"],
    cmd = """
        set -euo pipefail

        echo "==== /proc/self/cgroup ====" > $@
        cat /proc/self/cgroup >> $@
        echo "" >> $@

fzakaria

#! /usr/bin/env python3

import subprocess
import re
import datetime
from collections import defaultdict, Counter
import argparse
import os
import sys

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import sys
import os
from xml.etree import ElementTree as ET
from xml.dom import minidom

# Usage: python gen_classpath.py jars.txt /path/to/bazel/workspace

def find_binary_jar(source_jar):
    """Replace '-sources.jar' or '-src.jar' with '.jar' or 'lib' prefix if necessary"""
    dir_name, file_name = os.path.split(source_jar)

fzakaria

#! /usr/bin/env nix
#! nix shell github:tomberek/-#python3With.pyelftools --command python3

import sys
import subprocess
import re
import os
from elftools.elf.elffile import ELFFile
from elftools.elf.constants import SHN_INDICES

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build_event_stream_repo = use_extension("//tools/build_defs:bes_repo.bzl", "build_event_service_repo")
build_event_stream_repo.settings(
    name = "bazel_bes",
    revision = "7.4.1",
    sha256s = {
        "build_event_stream.proto": "7388663cc11b0642ffce0e3a14bd4c4902b913fb5697e5cf47b7a4d7c8ba5640",
        "command_line.proto": "a6fb6591aa50794431787169bc4fae16105ef5c401e7c30ecf0f775e0ab25c2c",
        "invocation_policy.proto": "7a1f9074d64aaea2c5fc01df093a25fbbd68d84db63fbfb355f5aa15683a75cd",
        "option_filters.proto": "bc1cc29e53e2856c3ae25149cc6661bb218737a9146e7417eb29f8caaa715821",