In general I'm not sure it's a good idea to rely too much on mmap
for the perf.data, but more about that later.
> +/* Host tools abort on failure; when linked into cc1, use gcc_assert. */
> +#ifdef IN_GCC
> +#define afdo_assert(EXPR) gcc_assert (EXPR)
> +#else
> +#include <cstdio>
> +#include <cstdlib>
> +#define afdo_assert(EXPR) \
> + ((void) (!(EXPR) \
> + ? (std::fprintf (stderr, \
> + "%s:%d: afdo_assert failed: %s\n", \
> + __FILE__, __LINE__, #EXPR), \
> + std::abort (), 0) \
> + : 0))
Could be just standard assert() ?
> + if (static_cast<uintmax_t> (st.st_size)
> + > static_cast<uintmax_t> (std::numeric_limits<size_t>::max ()))
> + {
> + ::close (fd);
> + return false;
> + }
I'm not sure how that could happen? Isn't size_t already 8 bytes
on a 64bit host?
> + const size_t len = static_cast<size_t> (st.st_size);
> + void *m = ::mmap (nullptr, len, PROT_READ, MAP_PRIVATE, fd, 0);
Do you really need MAP_PRIVATE to write to it? Otherwise MAP_SHARED.
> +
> +/* Mix VALUE into SEED (the Boost hash_combine mixing step). */
> +template <typename T>
> +void
> +hash_combine (size_t &seed, T value) noexcept
> +{
> + seed ^= static_cast<size_t> (value)
> + + static_cast<size_t> (0x9e3779b97f4a7c15ULL) + (seed << 6)
> + + (seed >> 2);
> +}
I would have assumed we have a suitable hash somewhere else, maybe
in libiberty.
> +void
> +start ()
> +{
> + s_start = clock_type::now ();
> + s_started = true;
> + s_stages.clear ();
> +}
Hmm are the tools so complicated that a standard profiler is not good
enough?
-Andi
