Commit Graph

10 Commits

Author SHA1 Message Date
Damien George
02d830c035 py: Introduce a Python stack for scoped allocation.
This patch introduces the MICROPY_ENABLE_PYSTACK option (disabled by
default) which enables a "Python stack" that allows to allocate and free
memory in a scoped, or Last-In-First-Out (LIFO) way, similar to alloca().

A new memory allocation API is introduced along with this Py-stack.  It
includes both "local" and "nonlocal" LIFO allocation.  Local allocation is
intended to be equivalent to using alloca(), whereby the same function must
free the memory.  Nonlocal allocation is where another function may free
the memory, so long as it's still LIFO.

Follow-up patches will convert all uses of alloca() and VLA to the new
scoped allocation API.  The old behaviour (using alloca()) will still be
available, but when MICROPY_ENABLE_PYSTACK is enabled then alloca() is no
longer required or used.

The benefits of enabling this option are (or will be once subsequent
patches are made to convert alloca()/VLA):
- Toolchains without alloca() can use this feature to obtain correct and
  efficient scoped memory allocation (compared to using the heap instead
  of alloca(), which is slower).
- Even if alloca() is available, enabling the Py-stack gives slightly more
  efficient use of stack space when calling nested Python functions, due to
  the way that compilers implement alloca().
- Enabling the Py-stack with the stackless mode allows for even more
  efficient stack usage, as well as retaining high performance (because the
  heap is no longer used to build and destroy stackless code states).
- With Py-stack and stackless enabled, Python-calling-Python is no longer
  recursive in the C mp_execute_bytecode function.

The micropython.pystack_use() function is included to measure usage of the
Python stack.
2017-12-11 13:49:09 +11:00
Alexander Steffen
55f33240f3 all: Use the name MicroPython consistently in comments
There were several different spellings of MicroPython present in comments,
when there should be only one.
2017-07-31 18:35:40 +10:00
Damien George
08242eed26 py/nlrsetjmp: Add check for failed NLR jump.
Also optimise the function so it only needs to call the MP_STATE_THREAD
macro once (following how other nlr code is written).
2017-04-12 13:50:31 +10:00
Damien George
94238d4ae5 py/nlrsetjmp: Update to take into account new location of nlr_top.
It's now accessed via the MP_STATE_THREAD macro.
2016-06-28 11:28:52 +01:00
Damien George
b4b10fd350 py: Put all global state together in state structures.
This patch consolidates all global variables in py/ core into one place,
in a global structure.  Root pointers are all located together to make
GC tracing easier and more efficient.
2015-01-07 20:33:00 +00:00
Damien George
8a2347723e py: Move global variable nlr_top to one place, in a .c file.
This reduces dependency on assembler, and allows to consolidate global
variables in the future.
2015-01-01 21:47:58 +00:00
Damien George
51dfcb4bb7 py: Move to guarded includes, everywhere in py/ core.
Addresses issue #1022.
2015-01-01 20:32:09 +00:00
Damien George
04b9147e15 Add license header to (almost) all files.
Blanket wide to all .c and .h files.  Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.

Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
2014-05-03 23:27:38 +01:00
Paul Sokolovsky
f54bcbf099 py, unix: Make "mpconfig.h" be first included, as other headers depend on it.
Specifically, nlr.h does.
2014-05-02 17:48:40 +03:00
Paul Sokolovsky
3a83b805fc nlr: Add implementation using setjmp/longjmp.
Having an optimized asm implementation is good, but if we want portability,
that's it.
2014-04-17 00:19:18 +03:00