Commit Graph

270 Commits

Author SHA1 Message Date
Damien George
5a2599d962 py: Replace POP_BLOCK and POP_EXCEPT opcodes with POP_EXCEPT_JUMP.
POP_BLOCK and POP_EXCEPT are now the same, and are always followed by a
JUMP.  So this optimisation reduces code size, and RAM usage of bytecode by
two bytes for each try-except handler.
2019-03-05 16:09:58 +11:00
Damien George
6f9e3ff719 py/vm: Remove currently_in_except_block variable.
After the previous commit it is no longer needed.
2019-03-05 16:09:41 +11:00
Damien George
e1fb03f3e2 py: Fix VM crash with unwinding jump out of a finally block.
This patch fixes a bug in the VM when breaking within a try-finally.  The
bug has to do with executing a break within the finally block of a
try-finally statement.  For example:

    def f():
        for x in (1,):
            print('a', x)
            try:
                raise Exception
            finally:
                print(1)
                break
            print('b', x)
    f()

Currently in uPy the above code will print:

    a 1
    1
    1
    segmentation fault (core dumped)  micropython

Not only is there a seg fault, but the "1" in the finally block is printed
twice.  This is because when the VM executes a finally block it doesn't
really know if that block was executed due to a fall-through of the try (no
exception raised), or because an exception is active.  In particular, for
nested finallys the VM has no idea which of the nested ones have active
exceptions and which are just fall-throughs.  So when a break (or continue)
is executed it tries to unwind all of the finallys, when in fact only some
may be active.

It's questionable whether break (or return or continue) should be allowed
within a finally block, because they implicitly swallow any active
exception, but nevertheless it's allowed by CPython (although almost never
used in the standard library).  And uPy should at least not crash in such a
case.

The solution here relies on the fact that exception and finally handlers
always appear in the bytecode after the try body.

Note: there was a similar bug with a return in a finally block, but that
was previously fixed in b735208403
2019-03-05 16:05:05 +11:00
Damien George
eee1e8841a py: Downcase all MP_OBJ_IS_xxx macros to make a more consistent C API.
These macros could in principle be (inline) functions so it makes sense to
have them lower case, to match the other C API functions.

The remaining macros that are upper case are:
- MP_OBJ_TO_PTR, MP_OBJ_FROM_PTR
- MP_OBJ_NEW_SMALL_INT, MP_OBJ_SMALL_INT_VALUE
- MP_OBJ_NEW_QSTR, MP_OBJ_QSTR_VALUE
- MP_OBJ_FUN_MAKE_SIG
- MP_DECLARE_CONST_xxx
- MP_DEFINE_CONST_xxx

These must remain macros because they are used when defining const data (at
least, MP_OBJ_NEW_SMALL_INT is so it makes sense to have
MP_OBJ_SMALL_INT_VALUE also a macro).

For those macros that have been made lower case, compatibility macros are
provided for the old names so that users do not need to change their code
immediately.
2019-02-12 14:54:51 +11:00
Paul Sokolovsky
8fea833e3f py: Update my copyright info on some files.
Based on git history.
2019-02-06 00:19:00 +11:00
Paul Sokolovsky
2f5d113fad py/warning: Support categories for warnings.
Python defines warnings as belonging to categories, where category is a
warning type (descending from exception type). This is useful, as e.g.
allows to disable warnings selectively and provide user-defined warning
types.  So, implement this in MicroPython, except that categories are
represented just with strings.  However, enough hooks are left to implement
categories differently per-port (e.g. as types), without need to patch each
and every usage.
2019-01-31 16:48:30 +11:00
Damien George
afecc124e6 py: Fix location of VM returned exception in invalid opcode and comments
The location for a returned exception was changed to state[0] in
d95947b48a
2019-01-04 17:22:40 +11:00
Damien George
d95947b48a py/vm: When VM raises exception put exc obj at beginning of func state.
Instead of at end of state, n_state - 1.  It was originally (way back in
v1.0) put at the end of the state because the VM didn't have a pointer to
the start.  But now that the VM takes a mp_code_state_t pointer it does
have a pointer to the start of the state so can put the exception object
there.

This commit saves about 30 bytes of code on all architectures, and, more
importantly, reduces C-stack usage by a couple of words (8 bytes on Thumb2
and 16 bytes on x86-64) for every (non-generator) call of a bytecode
function because fun_bc_call no longer needs to remember the n_state
variable.
2018-09-29 23:25:08 +10:00
Damien George
0c9d452370 py/vm: Fix case of throwing GeneratorExit type into yield-from.
mp_make_raise_obj must be used to convert a possible exception type to an
instance object, otherwise the VM may raise a non-exception object.

An existing test is adjusted to test this case, with the original test
already moved to generator_throw.py.
2018-09-28 11:39:35 +10:00
Damien George
6d20be31ae py/vm: Reword TODO about invalid ip/sp after an exception to a note. 2018-09-27 15:17:37 +10:00
Damien George
76355c8863 py/vm: Make small optimisation of BUILD_SLICE opcode.
No need to call DECODE_UINT since the value will always be either 2 or 3.
2018-09-27 11:22:33 +10:00
Damien George
b735208403 py/vm: Fix handling of finally-return with complex nested finallys.
Back in 8047340d75 basic support was added in
the VM to handle return statements within a finally block.  But it didn't
cover all cases, in particular when some finally's were active and others
inactive when the "return" was executed.

This patch adds further support for return-within-finally by correctly
managing the currently_in_except_block flag, and should fix all cases.  The
main point is that finally handlers remain on the exception stack even if
they are active (currently being executed), and the unwind return code
should only execute those finally's which are inactive.

New tests are added for the cases which now pass.
2018-09-03 13:08:16 +10:00
Damien George
bace1a16d0 py/objtype: Don't expose mp_obj_instance_attr().
mp_obj_is_instance_type() can be used instead to check for instance types.
2018-06-08 11:48:25 +10:00
Damien George
869024dd6e py/vm: Improve performance of opcode dispatch when using switch stmt.
Before this patch, when using the switch statement for dispatch in the VM
(not computed goto) a pending exception check was done after each opcode.
This is not necessary and this patch makes the pending exception check only
happen when explicitly requested by certain opcodes, like jump.  This
improves performance of the VM by about 2.5% when using the switch.
2018-05-18 11:47:03 +10:00
Damien George
46ce395130 py/vm: Use enum names instead of magic numbers in multi-opcode dispatch. 2018-05-18 11:44:26 +10:00
Damien George
1b7487e519 py/vm: Adjust #if logic for gil_divisor so braces are balanced.
Having balanced braces { and } makes it easier to navigate the function.
2018-05-16 12:33:39 +10:00
Damien George
bc36521386 py/vm: Optimise handling of stackless mode when pystack is enabled.
When pystack is enabled mp_obj_fun_bc_prepare_codestate() will always
return a valid pointer, and if there is no more pystack available then it
will raise an exception (a RuntimeError).  So having pystack enabled with
stackless enabled automatically gives strict stackless mode.  There is
therefore no need to have code for strict stackless mode when pystack is
enabled, and this patch optimises the VM for such a case.
2018-04-04 00:51:10 +10:00
Damien George
c7f880eda3 py/vm: Don't do unnecessary updates of ip and sp variables.
Neither the ip nor sp variables are used again after the execution of the
RAISE_VARARGS opcode, so they don't need to be updated.
2018-04-04 00:46:31 +10:00
Damien George
a9f6d49218 py/vm: Simplify handling of special-case STOP_ITERATION in yield from.
There's no need to have MP_OBJ_NULL a special case, the code can re-use
the MP_OBJ_STOP_ITERATION value to signal the special case and the VM can
detect this with only one check (for MP_OBJ_STOP_ITERATION).
2018-02-27 15:48:09 +11:00
Damien George
22ade2f5c4 py/vm: Fix case of handling raised StopIteration within yield from.
This patch concerns the handling of an NLR-raised StopIteration, raised
during a call to mp_resume() which is handling the yield from opcode.

Previously, commit 6738c1dded introduced code
to handle this case, along with a test.  It seems that it was lucky that
the test worked because the code did not correctly handle the stack pointer
(sp).

Furthermore, commit 79d996a57b improved the
way mp_resume() propagated certain exceptions: it changed raising an NLR
value to returning MP_VM_RETURN_EXCEPTION.  This change meant that the
test introduced in gen_yield_from_ducktype.py was no longer hitting the
code introduced in 6738c1dded.

The patch here does two things:

1. Fixes the handling of sp in the VM for the case that yield from is
   interrupted by a StopIteration raised via NLR.

2. Introduces a new test to check this handling of sp and re-covers the
   code in the VM.
2018-02-27 15:39:31 +11:00
Damien George
73d1d20b46 py/objexcept: Remove long-obsolete mp_const_MemoryError_obj.
This constant exception instance was once used by m_malloc_fail() to raise
a MemoryError without allocating memory, but it was made obsolete long ago
by 3556e45711.  The functionality is now
replaced by the use of mp_emergency_exception_obj which lives in the global
uPy state, and which can handle any exception type, not just MemoryError.
2018-02-15 16:50:02 +11:00
Damien George
0c650d4276 py/vm: Simplify stack sentinel values for unwind return and jump.
This patch simplifies how sentinel values are stored on the stack when
doing an unwind return or jump.  Instead of storing two values on the stack
for an unwind jump it now stores only one: a negative small integer means
unwind-return and a non-negative small integer means unwind-jump with the
value being the number of exceptions to unwind.  The savings in code size
are:

   bare-arm:   -56
minimal x86:   -68
   unix x64:   -80
unix nanbox:    -4
      stm32:   -56
     cc3200:   -64
    esp8266:   -76
      esp32:  -156
2018-02-08 13:30:33 +11:00
Damien George
30fd8484eb py/runtime: Use the Python stack when building *arg and **kwarg state.
With MICROPY_ENABLE_PYSTACK enabled the following language constructs no
longer allocate on the heap: f(*arg), f(**kwarg).
2017-12-11 13:49:09 +11:00
Damien George
1e5a33df41 py: Convert all uses of alloca() to use new scoped allocation API. 2017-12-11 13:49:09 +11:00
Damien George
5b8998da6d py/runtime: Move mp_exc_recursion_depth to runtime and rename to raise.
For consistency this helper function is renamed to match the other
exception helpers, and moved to their location in runtime.c.
2017-12-11 13:49:09 +11:00
Paul Sokolovsky
d72370def7 py/objfun, vm: Add comments on codestate allocation in stackless mode. 2017-12-09 11:01:34 +02:00
Damien George
a3dc1b1957 all: Remove inclusion of internal py header files.
Header files that are considered internal to the py core and should not
normally be included directly are:
    py/nlr.h - internal nlr configuration and declarations
    py/bc0.h - contains bytecode macro definitions
    py/runtime0.h - contains basic runtime enums

Instead, the top-level header files to include are one of:
    py/obj.h - includes runtime0.h and defines everything to use the
        mp_obj_t type
    py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
        and defines everything to use the general runtime support functions

Additional, specific headers (eg py/objlist.h) can be included if needed.
2017-10-04 12:37:50 +11:00
Damien George
e2ba45c35f py/vm: Use lowercase letter at start of exception message.
For consistency with all the other exception messages.
2017-09-22 11:28:45 +10:00
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
016325dd0a py/vm: Make n_state variable local to just set-up part of VM.
It's not used anywhere else in the VM loop, and clashes with (is shadowed
by) the n_state variable that's redeclared towards the end of the
mp_execute_bytecode function.  Code size is unchanged.
2017-07-18 16:17:23 +10:00
Damien George
9ed5e80eea py/vm: Make "if" control flow more obvious in YIELD_FROM opcode. 2017-07-04 02:14:25 +10:00
Damien George
a8a5d1e8c8 py: Provide mp_decode_uint_skip() to help reduce stack usage.
Taking the address of a local variable leads to increased stack usage, so
the mp_decode_uint_skip() function is added to reduce the need for taking
addresses.  The changes in this patch reduce stack usage of a Python call
by 8 bytes on ARM Thumb, by 16 bytes on non-windowing Xtensa archs, and by
16 bytes on x86-64.  Code size is also slightly reduced on most archs by
around 32 bytes.
2017-06-09 13:36:33 +10:00
Ville Skyttä
ca16c38210 various: Spelling fixes 2017-05-29 11:36:05 +03:00
Damien George
04d05db27e py/vm: Fix bug with unwind jump popping the iterator from a for loop.
This patch fixes a regression introduced by
088740ecc4
2017-05-25 20:39:08 +10:00
Damien George
68e71eacb8 py/vm: Fix bug with stackless mode and unwinding of exceptions.
This patch fixes a regression introduced by
71a3d6ec3b

Previous to this patch the n_state variable was referring to that computed
at the very start of the mp_execute_bytecode function.  This patch fixes it
so that n_state is recomputed when the code_state changes.
2017-05-25 20:35:57 +10:00
Damien George
dd11af209d py: Add LOAD_SUPER_METHOD bytecode to allow heap-free super meth calls.
This patch allows the following code to run without allocating on the heap:

    super().foo(...)

Before this patch such a call would allocate a super object on the heap and
then load the foo method and call it right away.  The super object is only
needed to perform the lookup of the method and not needed after that.  This
patch makes an optimisation to allocate the super object on the C stack and
discard it right after use.

Changes in code size due to this patch are:

   bare-arm: +128
    minimal: +232
   unix x64: +416
unix nanbox: +364
     stmhal: +184
    esp8266: +340
     cc3200: +128
2017-04-22 23:39:20 +10:00
Damien George
a0973b09ce py/vm: Fix VM opcode tracing to print correct stack pointer.
Also const_table is now moved to the code_state->fun_bc structure.
2017-03-27 10:52:04 +11:00
Damien George
707f16b05c py: Use mp_locals/mp_globals accessor funcs instead of MP_STATE_CTX.
To improve maintainability of the code.
2017-03-24 18:41:11 +11:00
Damien George
60656eaea4 py: Define and use MP_OBJ_ITER_BUF_NSLOTS to get size of stack iter buf.
It improves readability of code and reduces the chance to make a mistake.

This patch also fixes a bug with nan-boxing builds by rounding up the
calculation of the new NSLOTS variable, giving the correct number of slots
(being 4) even if mp_obj_t is larger than the native machine size.
2017-03-23 16:36:08 +11:00
Damien George
1a5c8d1053 py/vm: Don't release the GIL if the scheduler is locked.
The scheduler being locked general means we are running a scheduled
function, and switching to another thread violates that, so don't switch in
such a case (even though we technically could).

And if we are running a scheduled function then we want to finish it ASAP,
so we shouldn't switch to another thread.

Furthermore, ports with threading enabled will lock the scheduler during a
hard IRQ, and this patch to the VM will make sure that threads are not
switched during a hard IRQ (which would crash the VM).
2017-03-20 18:42:27 +11:00
Damien George
6e74d24f30 py: Add micropython.schedule() function and associated runtime code. 2017-03-20 15:20:26 +11:00
Damien George
5640e6dacd py: Provide mp_decode_uint_value to help optimise stack usage.
This has a noticeable improvement on x86-64 and Thumb2 archs, where stack
usage is reduced by 2 machine words in the VM.
2017-03-17 16:50:19 +11:00
Damien George
71a3d6ec3b py: Reduce size of mp_code_state_t structure.
Instead of caching data that is constant (code_info, const_table and
n_state), store just a pointer to the underlying function object from which
this data can be derived.

This helps reduce stack usage for the case when the mp_code_state_t
structure is stored on the stack, as well as heap usage when it's stored
on the heap.

The downside is that the VM becomes a little more complex because it now
needs to derive the data from the underlying function object.  But this
doesn't impact the performance by much (if at all) because most of the
decoding of data is done outside the main opcode loop.  Measurements using
pystone show that little to no performance is lost.

This patch also fixes a nasty bug whereby the bytecode can be reclaimed by
the GC during execution.  With this patch there is always a pointer to the
function object held by the VM during execution, since it's stored in the
mp_code_state_t structure.
2017-03-17 16:39:13 +11:00
Damien George
088740ecc4 py: Optimise storage of iterator so it takes only 4 slots on Py stack. 2017-02-16 18:38:06 +11:00
Damien George
6e769da0da py: Make FOR_ITER opcode pop 1+4 slots from the stack when finished.
The extra 4 slots correspond to the iterator object stored on the stack.
2017-02-16 18:38:06 +11:00
Damien George
f4df3aaa72 py: Allow bytecode/native to put iter_buf on stack for simple for loops.
So that the "for x in it: ..." statement can now work without using the
heap (so long as the iterator argument fits in an iter_buf structure).
2017-02-16 18:38:06 +11:00
Damien George
ae8d867586 py: Add iter_buf to getiter type method.
Allows to iterate over the following without allocating on the heap:
- tuple
- list
- string, bytes
- bytearray, array
- dict (not dict.keys, dict.values, dict.items)
- set, frozenset

Allows to call the following without heap memory:
- all, any, min, max, sum

TODO: still need to allocate stack memory in bytecode for iter_buf.
2017-02-16 18:38:06 +11:00
Damien George
101886f529 py/vm: Convert mp_uint_t to size_t where appropriate. 2017-02-16 16:51:17 +11:00
Damien George
f6c22a0679 py/vm: Add MICROPY_PY_THREAD_GIL_VM_DIVISOR option.
This improves efficiency of GIL release within the VM, by only doing the
release after a fixed number of jump-opcodes have executed in the current
thread.
2017-02-15 11:28:15 +11:00
Damien George
cc4c1adf6e py/showbc: Make sure to set the const_table before printing bytecode. 2017-01-27 12:34:09 +11:00