    const std = @import("std");
    const builtin = @import("builtin");
    const elf = std.elf;
    const assert = std.debug.assert;

    const R_AMD64_RELATIVE = 8;
    const R_386_RELATIVE = 8;
    const R_ARM_RELATIVE = 23;
    const R_AARCH64_RELATIVE = 1027;
    const R_RISCV_RELATIVE = 3;
    const R_SPARC_RELATIVE = 22;

    const R_RELATIVE = switch (builtin.cpu.arch) {
        .x86 => R_386_RELATIVE,
        .x86_64 => R_AMD64_RELATIVE,
        .arm => R_ARM_RELATIVE,
        .aarch64 => R_AARCH64_RELATIVE,
        .riscv64 => R_RISCV_RELATIVE,
        else => @compileError("Missing R_RELATIVE definition for this target"),
    };

    // Obtain a pointer to the _DYNAMIC array.

    // We have to compute its address as a PC-relative quantity not to require a

    // relocation that, at this point, is not yet applied.

    fn getDynamicSymbol() [*]elf.Dyn {
        return switch (builtin.cpu.arch) {
            .x86 => asm volatile (
                \\ .weak _DYNAMIC

                \\ .hidden _DYNAMIC

                \\ call 1f

                \\ 1: pop %[ret]

                \\ lea _DYNAMIC-1b(%[ret]), %[ret]

                : [ret] "=r" (-> [*]elf.Dyn),
            ),
            .x86_64 => asm volatile (
                \\ .weak _DYNAMIC

                \\ .hidden _DYNAMIC

                \\ lea _DYNAMIC(%%rip), %[ret]

                : [ret] "=r" (-> [*]elf.Dyn),
            ),
            // Work around the limited offset range of `ldr`

            .arm => asm volatile (
                \\ .weak _DYNAMIC

                \\ .hidden _DYNAMIC

                \\ ldr %[ret], 1f

                \\ add %[ret], pc

                \\ b 2f

                \\ 1: .word _DYNAMIC-1b

                \\ 2:

                : [ret] "=r" (-> [*]elf.Dyn),
            ),
            // A simple `adr` is not enough as it has a limited offset range

            .aarch64 => asm volatile (
                \\ .weak _DYNAMIC

                \\ .hidden _DYNAMIC

                \\ adrp %[ret], _DYNAMIC

                \\ add %[ret], %[ret], #:lo12:_DYNAMIC

                : [ret] "=r" (-> [*]elf.Dyn),
            ),
            .riscv64 => asm volatile (
                \\ .weak _DYNAMIC

                \\ .hidden _DYNAMIC

                \\ lla %[ret], _DYNAMIC

                : [ret] "=r" (-> [*]elf.Dyn),
            ),
            else => {
                @compileError("PIE startup is not yet supported for this target!");
            },
        };
    }

    pub fn relocate(phdrs: []elf.Phdr) void {
        @setRuntimeSafety(false);

        const dynv = getDynamicSymbol();
        // Recover the delta applied by the loader by comparing the effective and

        // the theoretical load addresses for the `_DYNAMIC` symbol.

        const base_addr = base: {
            for (phdrs) |*phdr| {
                if (phdr.p_type != elf.PT_DYNAMIC) continue;
                break :base @intFromPtr(dynv) - phdr.p_vaddr;
            }
            // This is not supposed to happen for well-formed binaries.

            std.os.abort();
        };

        var rel_addr: usize = 0;
        var rela_addr: usize = 0;
        var rel_size: usize = 0;
        var rela_size: usize = 0;
        {
            var i: usize = 0;
            while (dynv[i].d_tag != elf.DT_NULL) : (i += 1) {
                switch (dynv[i].d_tag) {
                    elf.DT_REL => rel_addr = base_addr + dynv[i].d_val,
                    elf.DT_RELA => rela_addr = base_addr + dynv[i].d_val,
                    elf.DT_RELSZ => rel_size = dynv[i].d_val,
                    elf.DT_RELASZ => rela_size = dynv[i].d_val,
                    else => {},
                }
            }
        }

        // Apply the relocations.

        if (rel_addr != 0) {
            const rel = std.mem.bytesAsSlice(elf.Rel, @as([*]u8, @ptrFromInt(rel_addr))[0..rel_size]);
            for (rel) |r| {
                if (r.r_type() != R_RELATIVE) continue;
                @as(*usize, @ptrFromInt(base_addr + r.r_offset)).* += base_addr;
            }
        }
        if (rela_addr != 0) {
            const rela = std.mem.bytesAsSlice(elf.Rela, @as([*]u8, @ptrFromInt(rela_addr))[0..rela_size]);
            for (rela) |r| {
                if (r.r_type() != R_RELATIVE) continue;
                @as(*usize, @ptrFromInt(base_addr + r.r_offset)).* += base_addr + @as(usize, @bitCast(r.r_addend));
            }
        }
    }