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2021-06-24all: Fix signed shifts and NULL access errors from -fsanitize=undefined.Jeff Epler
Fixes the following (the line numbers match commit 0e87459e2bfd07): ../../extmod/crypto-algorithms/sha256.c:49:19: runtime error: left shif... ../../extmod/moduasyncio.c:106:35: runtime error: member access within ... ../../py/binary.c:210:13: runtime error: left shift of negative value -... ../../py/mpz.c:744:16: runtime error: negation of -9223372036854775808 ... ../../py/objint.c:109:22: runtime error: left shift of 1 by 31 places c... ../../py/objint_mpz.c:374:9: runtime error: left shift of 4611686018427... ../../py/objint_mpz.c:374:9: runtime error: left shift of negative valu... ../../py/parsenum.c:106:14: runtime error: left shift of 46116860184273... ../../py/runtime.c:395:33: runtime error: left shift of negative value ... ../../py/showbc.c:177:28: runtime error: left shift of negative value -... ../../py/vm.c:321:36: runtime error: left shift of negative value -1``` Testing was done on an amd64 Debian Buster system using gcc-8.3 and these settings: CFLAGS += -g3 -Og -fsanitize=undefined LDFLAGS += -fsanitize=undefined The introduced TASK_PAIRHEAP macro's conditional (x ? &x->i : NULL) assembles (under amd64 gcc 8.3 -Os) to the same as &x->i, since i is the initial field of the struct. However, for the purposes of undefined behavior analysis the conditional is needed. Signed-off-by: Jeff Epler <jepler@gmail.com>
2021-06-19py/mpstate: Make exceptions thread-local.David Lechner
This moves mp_pending_exception from mp_state_vm_t to mp_state_thread_t. This allows exceptions to be scheduled on a specific thread. Signed-off-by: David Lechner <david@pybricks.com>
2021-03-17py/vm: For tracing use mp_printf, and print state when thread enabled.Damien George
mp_printf should be used to print the prefix because it's also used in mp_bytecode_print2 (otherwise, depending on the system, different output streams may be used). Also print the current thread state when threading is enabled to easily see which thread executes what opcode. Signed-off-by: Damien George <damien@micropython.org>
2020-09-11py/showbc: Pass in an mp_print_t struct to all bytecode-print functions.Damien George
So the output can be redirected if needed. Signed-off-by: Damien George <damien@micropython.org>
2020-04-13py/scheduler: Fix race in checking scheduler pending state.Jim Mussared
Because the atomic section starts after checking whether the scheduler state is pending, it's possible it can become a different state by the time the atomic section starts. This is especially likely on ports where MICROPY_BEGIN_ATOMIC_SECTION is implemented with a mutex (i.e. it might block), but the race exists regardless, i.e. if a context switch occurs between those two lines.
2020-04-05all: Use MP_ERROR_TEXT for all error messages.Jim Mussared
2020-02-28all: Add *FORMAT-OFF* in various places.Damien George
This string is recognised by uncrustify, to disable formatting in the region marked by these comments. This is necessary in the qstrdef*.h files to prevent modification of the strings within the Q(...). In other places it is used to prevent excessive reformatting that would make the code less readable.
2019-12-20py/vm: Fix comment to refer to MP_BC_RAISE_OBJ instead of RAISE_VARARGS.Damien George
2019-10-04py/runtime: Fix PEP479 behaviour throwing StopIteration into yield from.Damien George
Commit 3f6ffe059f64b3ebc44dc0bbc63452cb8850702b implemented PEP479 but did not catch the case fixed in this commit. Found by coverage analysis, that the VM had uncovered code.
2019-10-04py/vm: Fix handling of unwind jump out of active finally.Damien George
Prior to this commit, when unwinding through an active finally the stack was not being correctly popped/folded, which resulting in the VM crashing for complicated unwinding of nested finallys. This should be fixed with this commit, and more tests for return/break/ continue within a finally have been added to exercise this.
2019-10-01py: Rework and compress second part of bytecode prelude.Damien George
This patch compresses the second part of the bytecode prelude which contains the source file name, function name, source-line-number mapping and cell closure information. This part of the prelude now begins with a single varible length unsigned integer which encodes 2 numbers, being the byte-size of the following 2 sections in the header: the "source info section" and the "closure section". After decoding this variable unsigned integer it's possible to skip over one or both of these sections very easily. This scheme saves about 2 bytes for most functions compared to the original format: one in the case that there are no closure cells, and one because padding was eliminated.
2019-10-01py: Compress first part of bytecode prelude.Damien George
The start of the bytecode prelude contains 6 numbers telling the amount of stack needed for the Python values and exceptions, and the signature of the function. Prior to this patch these numbers were all encoded one after the other (2x variable unsigned integers, then 4x bytes), but using so many bytes is unnecessary. An entropy analysis of around 150,000 bytecode functions from the CPython standard library showed that the optimal Shannon coding would need about 7.1 bits on average to encode these 6 numbers, compared to the existing 48 bits. This patch attempts to get close to this optimal value by packing the 6 numbers into a single, varible-length unsigned integer via bit-wise interleaving. The interleaving scheme is chosen to minimise the average number of bytes needed, and at the same time keep the scheme simple enough so it can be implemented without too much overhead in code size or speed. The scheme requires about 10.5 bits on average to store the 6 numbers. As a result most functions which originally took 6 bytes to encode these 6 numbers now need only 1 byte (in 80% of cases).
2019-10-01py: Add n_state to mp_code_state_t struct.Damien George
This value is used often enough that it is better to cache it instead of decode it each time.
2019-10-01py/bc: Change mp_code_state_t.exc_sp to exc_sp_idx.Damien George
Change from a pointer to an index, to make space in mp_code_state_t.
2019-09-26py: Split RAISE_VARARGS opcode into 3 separate ones.Damien George
From the beginning of this project the RAISE_VARARGS opcode was named and implemented following CPython, where it has an argument (to the opcode) counting how many args the raise takes: raise # 0 args (re-raise previous exception) raise exc # 1 arg raise exc from exc2 # 2 args (chained raise) In the bytecode this operation therefore takes 2 bytes, one for RAISE_VARARGS and one for the number of args. This patch splits this opcode into 3, where each is now a single byte. This reduces bytecode size by 1 byte for each use of raise. Every byte counts! It also has the benefit of reducing code size (on all ports except nanbox).
2019-09-26py: Introduce and use constants for multi-opcode sizes.Damien George
2019-09-10py/vm: Factor cached map lookup code to inline function.Damien George
To reduce code duplication and allow to more easily modify this function.
2019-08-30py: Integrate sys.settrace feature into the VM and runtime.Milan Rossa
This commit adds support for sys.settrace, allowing to install Python handlers to trace execution of Python code. The interface follows CPython as closely as possible. The feature is disabled by default and can be enabled via MICROPY_PY_SYS_SETTRACE.
2019-08-30py/bc: Factor out code to get bytecode line number info into new func.Damien George
2019-08-28py/vm: Don't add traceback info for exceptions that are re-raised.Damien George
With this patch exceptions that are re-raised have improved tracebacks (less confusing, match CPython), and it makes re-raise slightly more efficient (in time and RAM) because they no longer need to add a traceback. Also general VM performance is not measurably affected. Partially fixes issue #2928.
2019-08-28py/vm: Don't add traceback info for exc's propagated through a finally.Damien George
With this patch exception tracebacks that go through a finally are improved (less confusing, match CPython), and it makes finally's slightly more efficient (in time and RAM) because they no longer need to add a traceback. Partially fixes issue #2928.
2019-08-22py/vm: Shorten error message for not-implemented opcode.Damien George
It's really an opcode that's not implemented, so use "opcode" instead of "byte code". And remove the redundant "not implemented" text because that is already implied by the exception type. There's no need to have a long error message for an exception that is almost never encountered. Saves about 20 bytes of code size on most ports.
2019-05-27py/vm: Remove obsolete comments about matching of exception opcodes.Damien George
These are incorrect since 5a2599d96299ad37cda954f1de345159f9acf11c
2019-03-05py: Replace POP_BLOCK and POP_EXCEPT opcodes with POP_EXCEPT_JUMP.Damien George
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.
2019-03-05py/vm: Remove currently_in_except_block variable.Damien George
After the previous commit it is no longer needed.
2019-03-05py: Fix VM crash with unwinding jump out of a finally block.Damien George
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 b735208403a54774f9fd3d966f7c1a194c41870f
2019-02-12py: Downcase all MP_OBJ_IS_xxx macros to make a more consistent C API.Damien George
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.
2019-02-06py: Update my copyright info on some files.Paul Sokolovsky
Based on git history.
2019-01-31py/warning: Support categories for warnings.Paul Sokolovsky
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.
2019-01-04py: Fix location of VM returned exception in invalid opcode and commentsDamien George
The location for a returned exception was changed to state[0] in d95947b48a30f818638c3619b92110ce6d07f5e3
2018-09-29py/vm: When VM raises exception put exc obj at beginning of func state.Damien George
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.
2018-09-28py/vm: Fix case of throwing GeneratorExit type into yield-from.Damien George
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.
2018-09-27py/vm: Reword TODO about invalid ip/sp after an exception to a note.Damien George
2018-09-27py/vm: Make small optimisation of BUILD_SLICE opcode.Damien George
No need to call DECODE_UINT since the value will always be either 2 or 3.
2018-09-03py/vm: Fix handling of finally-return with complex nested finallys.Damien George
Back in 8047340d7532ec32bc9f2d603bffc0bc9544297f 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.
2018-06-08py/objtype: Don't expose mp_obj_instance_attr().Damien George
mp_obj_is_instance_type() can be used instead to check for instance types.
2018-05-18py/vm: Improve performance of opcode dispatch when using switch stmt.Damien George
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.
2018-05-18py/vm: Use enum names instead of magic numbers in multi-opcode dispatch.Damien George
2018-05-16py/vm: Adjust #if logic for gil_divisor so braces are balanced.Damien George
Having balanced braces { and } makes it easier to navigate the function.
2018-04-04py/vm: Optimise handling of stackless mode when pystack is enabled.Damien George
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.
2018-04-04py/vm: Don't do unnecessary updates of ip and sp variables.Damien George
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.
2018-02-27py/vm: Simplify handling of special-case STOP_ITERATION in yield from.Damien George
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).
2018-02-27py/vm: Fix case of handling raised StopIteration within yield from.Damien George
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 6738c1dded8e436686f85008ec0a4fc47406ab7a 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 79d996a57b351e0ef354eb1e2f644b194433cc73 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 6738c1dded8e436686f85008ec0a4fc47406ab7a. 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.
2018-02-15py/objexcept: Remove long-obsolete mp_const_MemoryError_obj.Damien George
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 3556e45711c3b7ec712748d013e678d035185bdd. 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.
2018-02-08py/vm: Simplify stack sentinel values for unwind return and jump.Damien George
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
2017-12-11py/runtime: Use the Python stack when building *arg and **kwarg state.Damien George
With MICROPY_ENABLE_PYSTACK enabled the following language constructs no longer allocate on the heap: f(*arg), f(**kwarg).
2017-12-11py: Convert all uses of alloca() to use new scoped allocation API.Damien George
2017-12-11py/runtime: Move mp_exc_recursion_depth to runtime and rename to raise.Damien George
For consistency this helper function is renamed to match the other exception helpers, and moved to their location in runtime.c.
2017-12-09py/objfun, vm: Add comments on codestate allocation in stackless mode.Paul Sokolovsky
2017-10-04all: Remove inclusion of internal py header files.Damien George
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.