[PATCH] PGO: llvm-profdata: tool for merging profiles

[Justin Bogner]

"Duncan P. N. Exon Smith" <dexonsmith at apple.com> writes:
> Introducing llvm-profdata, a tool for merging profile data generated by
> PGO instrumentation in clang.
>
> - The name indicates a file extension of <name>.profdata.  Eventually
>   profile data output by clang should be changed to that extension.
>
> - llvm-profdata merges two profiles.  However, the name is more general,
>   since it will likely pick up more tasks (such as summarizing a single
>   profile).
>
> - llvm-profdata parses the current text-based format, but will be
>   updated once we settle on a binary format.

LGTM with a minor whitespace problem.

> +static bool getNumber(const StringRef &S, uint64_t &N) {
> +  N = 0;
> +  for (StringRef::iterator I = S.begin(), E = S.end(); I != E; ++I)
> +    if (*I >= '0' && *I <= '9')
> +      N = N*10 + (*I - '0');
              ^
Spaces around operator.