We use small_object_allocator to allocate vm_obj's.
However small_object_allocator is not thread safe. So, we need to copy
vm_obj's between threads. Moreover, in our experiments, we observed that
JEMALLOC is actually faster than the small_object_allocator.
Here are numbers for the reduced corelib.
small_object_allocator: 15.62 secs
gcc 4.9 allocator: 16.19 secs
jemalloc: 13.83 secs
The tactic_state object will contain a name_generator for creating fresh
names. `tactic_state.mk_empty` is bad because it does not have sufficient
information to create this name_generator.
Moreover `tactic_state.mk_empty` was only being used to convert
`tactic A` into a `parser A`.
We implement this primitive now in C++. In C++, we will be able
to use the parser name generator to initialize a fresh `tactic_state`.
It fixes the issue by propagating the correct information to the
equation compiler.
The fix may be a little bit hackish, but it is comapatible with
the approach we are already using: store `m_is_meta` flag in the equation
macro.
Disclaimer: we may still have other instances of this bug, since
the information may still be propagated incorrectly in other places.
I will not refactor this code right now nor accept any PR that
changes the current design. I am busy in other parts of the code
base and do not have time to do the context switch required for
implementing this kind of change and/or review the PR and make sure I'm
happy with it.
They can be used to store user state in the tactic_state object.
@Armael @jroesch: The new file tests/lean/run/tactic_ref.lean contains a few examples.
