Commit Graph

35 Commits

Author SHA1 Message Date
Damien George 34c04d2319 py/nlrthumb: Save and restore VFP registers s16-s21 when CPU has them.
These s16-s21 registers are used by gcc so need to be saved.  Future
versions of gcc (beyond v9.1.0), or other compilers, may eventually need
additional registers saved/restored.

See issue #4844.
2019-06-19 14:53:17 +10:00
stijn b184b6ae53 py/nlr: Fix nlr functions for 64bit ports built with gcc on Windows
The number of registers used should be 10, not 12, to match the assembly
code in nlrx64.c. With this change the 64bit mingw builds don't need to
use the setjmp implementation, and this fixes miscellaneous crashes and
assertion failures as reported in #1751 for instance.

To avoid mistakes in the future where something gcc-related for Windows
only gets fixed for one particular compiler/environment combination,
make use of a MICROPY_NLR_OS_WINDOWS macro.

To make sure everything nlr-related is now ok when built with gcc this
has been verified with:
- unix port built with gcc on Cygwin (i686-pc-cygwin-gcc and
  x86_64-pc-cygwin-gcc, version 6.4.0)
- windows port built with mingw-w64's gcc from Cygwin
 (i686-w64-mingw32-gcc and x86_64-w64-mingw32-gcc, version 6.4.0)
 and MSYS2 (like the ones on Cygwin but version 7.2.0)
2017-12-29 22:24:46 +11:00
Damien George b25f92160b py/nlr: Factor out common NLR code to macro and generic funcs in nlr.c.
Each NLR implementation (Thumb, x86, x64, xtensa, setjmp) duplicates a lot
of the NLR code, specifically that dealing with pushing and popping the NLR
pointer to maintain the linked-list of NLR buffers.  This patch factors all
of that code out of the specific implementations into generic functions in
nlr.c, along with a helper macro in nlr.h.  This eliminates duplicated
code.
2017-12-28 16:46:30 +11:00
Damien George 5bf8e85fc8 py/nlr: Clean up selection and config of NLR implementation.
If MICROPY_NLR_SETJMP is not enabled and the machine is auto-detected then
nlr.h now defines some convenience macros for the individual NLR
implementations to use (eg MICROPY_NLR_THUMB).  This keeps nlr.h and the
implementation in sync, and also makes the nlr_buf_t struct easier to read.
2017-12-28 16:18:39 +11:00
Paul Sokolovsky 096e967aad Revert "py/nlr: Factor out common NLR code to generic functions."
This reverts commit 6a3a742a6c.

The above commit has number of faults starting from the motivation down
to the actual implementation.

1. Faulty implementation.

The original code contained functions like:

NORETURN void nlr_jump(void *val) {
    nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
    nlr_buf_t *top = *top_ptr;
...
     __asm volatile (
    "mov    %0, %%edx           \n" // %edx points to nlr_buf
    "mov    28(%%edx), %%esi    \n" // load saved %esi
    "mov    24(%%edx), %%edi    \n" // load saved %edi
    "mov    20(%%edx), %%ebx    \n" // load saved %ebx
    "mov    16(%%edx), %%esp    \n" // load saved %esp
    "mov    12(%%edx), %%ebp    \n" // load saved %ebp
    "mov    8(%%edx), %%eax     \n" // load saved %eip
    "mov    %%eax, (%%esp)      \n" // store saved %eip to stack
    "xor    %%eax, %%eax        \n" // clear return register
    "inc    %%al                \n" // increase to make 1, non-local return
     "ret                        \n" // return
    :                               // output operands
    : "r"(top)                      // input operands
    :                               // clobbered registers
     );
}

Which clearly stated that C-level variable should be a parameter of the
assembly, whcih then moved it into correct register.

Whereas now it's:

NORETURN void nlr_jump_tail(nlr_buf_t *top) {
    (void)top;

    __asm volatile (
    "mov    28(%edx), %esi      \n" // load saved %esi
    "mov    24(%edx), %edi      \n" // load saved %edi
    "mov    20(%edx), %ebx      \n" // load saved %ebx
    "mov    16(%edx), %esp      \n" // load saved %esp
    "mov    12(%edx), %ebp      \n" // load saved %ebp
    "mov    8(%edx), %eax       \n" // load saved %eip
    "mov    %eax, (%esp)        \n" // store saved %eip to stack
    "xor    %eax, %eax          \n" // clear return register
    "inc    %al                 \n" // increase to make 1, non-local return
    "ret                        \n" // return
    );

    for (;;); // needed to silence compiler warning
}

Which just tries to perform operations on a completely random register (edx
in this case). The outcome is the expected: saving the pure random luck of
the compiler putting the right value in the random register above, there's
a crash.

2. Non-critical assessment.

The original commit message says "There is a small overhead introduced
(typically 1 machine instruction)". That machine instruction is a call
if a compiler doesn't perform tail optimization (happens regularly), and
it's 1 instruction only with the broken code shown above, fixing it
requires adding more. With inefficiencies already presented in the NLR
code, the overhead becomes "considerable" (several times more than 1%),
not "small".

The commit message also says "This eliminates duplicated code.". An
obvious way to eliminate duplication would be to factor out common code
to macros, not introduce overhead and breakage like above.

3. Faulty motivation.

All this started with a report of warnings/errors happening for a niche
compiler. It could have been solved in one the direct ways: a) fixing it
just for affected compiler(s); b) rewriting it in proper assembly (like
it was before BTW); c) by not doing anything at all, MICROPY_NLR_SETJMP
exists exactly to address minor-impact cases like thar (where a) or b) are
not applicable). Instead, a backwards "solution" was put forward, leading
to all the issues above.

The best action thus appears to be revert and rework, not trying to work
around what went haywire in the first place.
2017-12-26 19:27:58 +02:00
Damien George 6a3a742a6c py/nlr: Factor out common NLR code to generic functions.
Each NLR implementation (Thumb, x86, x64, xtensa, setjmp) duplicates a lot
of the NLR code, specifically that dealing with pushing and popping the NLR
pointer to maintain the linked-list of NLR buffers.  This patch factors all
of that code out of the specific implementations into generic functions in
nlr.c.  This eliminates duplicated code.

The factoring also allows to make the machine-specific NLR code pure
assembler code, thus allowing nlrthumb.c to use naked function attributes
in the correct way (naked functions can only have basic inline assembler
code in them).

There is a small overhead introduced (typically 1 machine instruction)
because now the generic nlr_jump() must call nlr_jump_tail() rather than
them being one combined function.
2017-12-20 15:42:06 +11:00
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
Alexander Steffen 299bc62586 all: Unify header guard usage.
The code conventions suggest using header guards, but do not define how
those should look like and instead point to existing files. However, not
all existing files follow the same scheme, sometimes omitting header guards
altogether, sometimes using non-standard names, making it easy to
accidentally pick a "wrong" example.

This commit ensures that all header files of the MicroPython project (that
were not simply copied from somewhere else) follow the same pattern, that
was already present in the majority of files, especially in the py folder.

The rules are as follows.

Naming convention:
* start with the words MICROPY_INCLUDED
* contain the full path to the file
* replace special characters with _

In addition, there are no empty lines before #ifndef, between #ifndef and
one empty line before #endif. #endif is followed by a comment containing
the name of the guard macro.

py/grammar.h cannot use header guards by design, since it has to be
included multiple times in a single C file. Several other files also do not
need header guards as they are only used internally and guaranteed to be
included only once:
* MICROPY_MPHALPORT_H
* mpconfigboard.h
* mpconfigport.h
* mpthreadport.h
* pin_defs_*.h
* qstrdefs*.h
2017-07-18 11:57:39 +10:00
stijn 2f0ce2a6f5 py: Cleanup use of global DEBUG preprocessor definition
The standard preprocessor definition to differentiate debug and non-debug
builds is NDEBUG, not DEBUG, so don't rely on the latter:
- just delete the use of it in objint_longlong.c as it has been stale code
  for years anyway (since commit [c4029e5]): SUFFIX isn't used anywhere.
- replace DEBUG with MICROPY_DEBUG_NLR in nlr.h: it is rarely used anymore
  so can be off by default
2017-04-30 14:28:37 +03:00
Damien George be3d7f91e5 py/nlr.h: Mark nlr_jump_fail as NORETURN. 2017-03-06 17:13:16 +11:00
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 999cedb90f py: Wrap all obj-ptr conversions in MP_OBJ_TO_PTR/MP_OBJ_FROM_PTR.
This allows the mp_obj_t type to be configured to something other than a
pointer-sized primitive type.

This patch also includes additional changes to allow the code to compile
when sizeof(mp_uint_t) != sizeof(void*), such as using size_t instead of
mp_uint_t, and various casts.
2015-11-29 14:25:35 +00:00
stijn 803264bb17 py: Guard against redef of nlr_push with DEBUG + MICROPY_NLR_SETJMP. 2015-03-03 14:34:40 +00:00
Paul Sokolovsky 3077fbff26 nlr: Add even more optional debugging logging.
Has to be enabled by manual editing, but at least it's there, as debugging
NLR issues may be weird.
2015-02-15 20:28:18 +03:00
Paul Sokolovsky e89cc13e5c nlr: If DEBUG, guard against recursive nlr_push().
Pushing same NLR record twice would lead to "infinite loop" in nlr_jump
(but more realistically, it will crash as soon as NLR record on stack is
overwritten).
2015-02-15 20:23:52 +03:00
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 2399aa03b8 py: Add NLR support for xtensa CPU. 2014-11-27 20:29:33 +00:00
Damien George 7860c2a68a py: Fix some macros defines; cleanup some includes. 2014-11-05 21:16:41 +00:00
Paul Sokolovsky a96cc824bd py: Support arm and thumb ARM ISAs, in addition to thumb2.
These changes were tested with QEMU, and by few people of real hardware.
2014-06-22 01:40:45 +03:00
Emmanuel Blot bf3366a48b Add missing “assert.h” file header inclusion from “nlr.h” 2014-06-19 18:47:38 +02:00
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 e908591baa py: Abstract no-return attribute for functions a bit. 2014-04-30 05:35:18 +03:00
Paul Sokolovsky 851c856585 nlr.h: As we treat all warnings as errors, can't use #warning.
And this is not good.
2014-04-30 04:14:31 +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
Damien George 26cf55ae05 Add a check for NULL nlr_top in nlr_jump.
If no nlr_buf has been pushed, and an nlr_jump is called, then control
is transferred to nlr_jump_fail (which should bail out with a fatal
error).
2014-04-08 14:08:14 +00:00
Damien George ea13f407a3 py: Change nlr_jump to nlr_raise, to aid in debugging.
This does not affect code size or performance when debugging turned off.

To address issue #420.
2014-04-05 18:32:08 +01:00
Damien George 4b34c76fd6 Changes to get unix/ port compiling on Cygwin. 2014-04-03 23:51:16 +01:00
Paul Sokolovsky 82a165d9be nlr.h: Do proper arch selection, using the same tests as nlr*.S . 2014-03-01 10:05:33 +02:00
Damien 8b3a7c2237 Fix func decls with no arguments: () -> (void). 2013-10-23 20:20:17 +01:00
Damien 152568bcb6 NLR and Python exceptions work on the board. 2013-10-16 00:46:39 +01:00
Damien ce89a21ea4 Implement basic exception framework, and simple for loop. 2013-10-15 22:25:17 +01:00