parseDbiStream

pub fn parseDbiStream(self: *Pdb) !void {
    var stream = self.getStream(pdb.StreamType.dbi) orelse
        return error.InvalidDebugInfo;
    const reader = stream.reader();

    const header = try reader.readStruct(std.pdb.DbiStreamHeader);
    if (header.version_header != 19990903) // V70, only value observed by LLVM team
        return error.UnknownPDBVersion;
    // if (header.Age != age)
    //     return error.UnmatchingPDB;

    const mod_info_size = header.mod_info_size;
    const section_contrib_size = header.section_contribution_size;

    var modules = std.array_list.Managed(Module).init(self.allocator);
    errdefer modules.deinit();

    // Module Info Substream
    var mod_info_offset: usize = 0;
    while (mod_info_offset != mod_info_size) {
        const mod_info = try reader.readStruct(pdb.ModInfo);
        var this_record_len: usize = @sizeOf(pdb.ModInfo);

        const module_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
        errdefer self.allocator.free(module_name);
        this_record_len += module_name.len + 1;

        const obj_file_name = try reader.readUntilDelimiterAlloc(self.allocator, 0, 1024);
        errdefer self.allocator.free(obj_file_name);
        this_record_len += obj_file_name.len + 1;

        if (this_record_len % 4 != 0) {
            const round_to_next_4 = (this_record_len | 0x3) + 1;
            const march_forward_bytes = round_to_next_4 - this_record_len;
            try stream.seekBy(@as(isize, @intCast(march_forward_bytes)));
            this_record_len += march_forward_bytes;
        }

        try modules.append(Module{
            .mod_info = mod_info,
            .module_name = module_name,
            .obj_file_name = obj_file_name,

            .populated = false,
            .symbols = undefined,
            .subsect_info = undefined,
            .checksum_offset = null,
        });

        mod_info_offset += this_record_len;
        if (mod_info_offset > mod_info_size)
            return error.InvalidDebugInfo;
    }

    // Section Contribution Substream
    var sect_contribs = std.array_list.Managed(pdb.SectionContribEntry).init(self.allocator);
    errdefer sect_contribs.deinit();

    var sect_cont_offset: usize = 0;
    if (section_contrib_size != 0) {
        const version = reader.readEnum(std.pdb.SectionContrSubstreamVersion, .little) catch |err| switch (err) {
            error.InvalidValue => return error.InvalidDebugInfo,
            else => |e| return e,
        };
        _ = version;
        sect_cont_offset += @sizeOf(u32);
    }
    while (sect_cont_offset != section_contrib_size) {
        const entry = try sect_contribs.addOne();
        entry.* = try reader.readStruct(pdb.SectionContribEntry);
        sect_cont_offset += @sizeOf(pdb.SectionContribEntry);

        if (sect_cont_offset > section_contrib_size)
            return error.InvalidDebugInfo;
    }

    self.modules = try modules.toOwnedSlice();
    self.sect_contribs = try sect_contribs.toOwnedSlice();
}