[LLVMdev] [RFC] Moving OnDiskHashTable from clang to LLVM

[Justin Bogner]

Rafael Avila de Espindola <rafael.espindola at gmail.com> writes:
>> On Mar 22, 2014, at 1:31, Justin Bogner <mail at justinbogner.com> wrote:
>> Also, the header includes a "clang::io" namespace with some operations
>> for reading and writing little endian files. Should these be directly
>> renamed to "llvm::io", or would something like "llvm::endian::little" or
>> "llvm::le" be more reasonable?
>
> Llvm has lib/support/endian.h. Wouldn't the new API be redundant? If
> not, would it fit in that header?

They're obviously related. Endian.h defines types like ulittle32, which
DTRT when read and written from memory, whereas clang::io has functions
to read and write memory like so:

    void Emit32(raw_ostream& Out, uint32_t V);
    uint32_t ReadLE32(const unsigned char *&Data);
    uint32_t ReadUnalignedLE32(const unsigned char *&Data);

The (aligned) ReadLE32 is easily represented by the stuff in Endian.h,
but the write to an ostream and reading unaligned aren't addressed very
well at present.

We could still add this stuff to Endian.h, assuming it isn't an issue to
depend on raw_ostream.h from Endian.h. I'm not sure if that'd be a
problem or not.