4f3d9429b5
Prior to this commit a function compiled with the native decorator @micropython.native would not work correctly when accessing global variables, because the globals dict was not being set upon function entry. This commit fixes this problem by, upon function entry, setting as the current globals dict the globals dict context the function was defined within, as per normal Python semantics, and as bytecode does. Upon function exit the original globals dict is restored. In order to restore the globals dict when an exception is raised the native function must guard its internals with an nlr_push/nlr_pop pair. Because this push/pop is relatively expensive, in both C stack usage for the nlr_buf_t and CPU execution time, the implementation here optimises things as much as possible. First, the compiler keeps track of whether a function even needs to access global variables. Using this information the native emitter then generates three different kinds of code: 1. no globals used, no exception handlers: no nlr handling code and no setting of the globals dict. 2. globals used, no exception handlers: an nlr_buf_t is allocated on the C stack but it is not used if the globals dict is unchanged, saving execution time because nlr_push/nlr_pop don't need to run. 3. function has exception handlers, may use globals: an nlr_buf_t is allocated and nlr_push/nlr_pop are always called. In the end, native functions that don't access globals and don't have exception handlers will run more efficiently than those that do. Fixes issue #1573.
This directory contains tests for various functionality areas of MicroPython. To run all stable tests, run "run-tests" script in this directory. Tests of capabilities not supported on all platforms should be written to check for the capability being present. If it is not, the test should merely output 'SKIP' followed by the line terminator, and call sys.exit() to raise SystemExit, instead of attempting to test the missing capability. The testing framework (run-tests in this directory, test_main.c in qemu_arm) recognizes this as a skipped test. There are a few features for which this mechanism cannot be used to condition a test. The run-tests script uses small scripts in the feature_check directory to check whether each such feature is present, and skips the relevant tests if not. When creating new tests, anything that relies on float support should go in the float/ subdirectory. Anything that relies on import x, where x is not a built-in module, should go in the import/ subdirectory.