Makes the prof sample prng use the tsd prng_state. This allows us to properly
initialize the sample interval event, without having to create tdata. As a
result, tdata will be created on demand (when a thread reaches the sample
interval bytes allocated), instead of on the first allocation.
Clang since r369414 (clang-10) can now check -Wimplicit-fallthrough for
C code, and use the GNU C style attribute to denote fallthrough.
Move the test from header only to autoconf. The previous test used
brittle version detection which did not work for newer clang that
supported this feature.
The attribute has to be its own statement, hence the added `;`. It also
can only precede case statements, so the final cases should be
explicitly terminated with break statements.
Fixes commit 3d29d11ac2 ("Clean compilation -Wextra")
Link: 1e0affb6e5
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
some architecture like AArch64 may not have the open syscall, but have
openat syscall. so check and use SYS_openat if SYS_openat available if
SYS_open is not supported at init_thp_state.
`tcache_bin_info` is not accessed on malloc fast path but the
compiler reserves a register for it, as well as an additional
register for `tcache_bin_info[ind].stack_size`. The optimization
gets rid of the need for the two registers.
This change suppresses tdata initialization and prof sample threshold
update in interrupting malloc calls. Interrupting calls have no need
for tdata. Delaying tdata creation aligns better with our lazy tdata
creation principle, and it also helps us gain control back from
interrupting calls more quickly and reduces any risk of delegating
tdata creation to an interrupting call.
Specifically, the extent_arena_[g|s]et functions and the address randomization.
These are the only things that tie the extent struct itself to the arena code.
