pub const SuperBlock = extern structpub const SuperBlock = extern struct {
/// The LLVM docs list a space between C / C++ but empirically this is not the case.
pub const expect_magic = "Microsoft C/C++ MSF 7.00\r\n\x1a\x44\x53\x00\x00\x00";
file_magic: [expect_magic.len]u8,
/// The block size of the internal file system. Valid values are 512, 1024,
/// 2048, and 4096 bytes. Certain aspects of the MSF file layout vary depending
/// on the block sizes. For the purposes of LLVM, we handle only block sizes of
/// 4KiB, and all further discussion assumes a block size of 4KiB.
block_size: u32,
/// The index of a block within the file, at which begins a bitfield representing
/// the set of all blocks within the file which are “free” (i.e. the data within
/// that block is not used). See The Free Block Map for more information. Important:
/// FreeBlockMapBlock can only be 1 or 2!
free_block_map_block: u32,
/// The total number of blocks in the file. NumBlocks * BlockSize should equal the
/// size of the file on disk.
num_blocks: u32,
/// The size of the stream directory, in bytes. The stream directory contains
/// information about each stream’s size and the set of blocks that it occupies.
/// It will be described in more detail later.
num_directory_bytes: u32,
unknown: u32,
/// The index of a block within the MSF file. At this block is an array of
/// ulittle32_t’s listing the blocks that the stream directory resides on.
/// For large MSF files, the stream directory (which describes the block
/// layout of each stream) may not fit entirely on a single block. As a
/// result, this extra layer of indirection is introduced, whereby this
/// block contains the list of blocks that the stream directory occupies,
/// and the stream directory itself can be stitched together accordingly.
/// The number of ulittle32_t’s in this array is given by
/// ceil(NumDirectoryBytes / BlockSize).
// Note: microsoft-pdb code actually suggests this is a variable-length
// array. If the indices of blocks occupied by the Stream Directory didn't
// fit in one page, there would be other u32 following it.
// This would mean the Stream Directory is bigger than BlockSize / sizeof(u32)
// blocks. We're not even close to this with a 1GB pdb file, and LLVM didn't
// implement it so we're kind of safe making this assumption for now.
block_map_addr: u32,
}