* The compiler analyzes the usage of the first 64 local variables all at once using bit masks.
* Local variables beyond the first 64 are only partially analyzed, achieving linear time.
Inlining of code that corresponds to source code lines, can make it hard to distinguish later between code which is only reachable from except handlers, and that which is reachable in normal control flow. This caused problems with the debugger's jump feature.
This PR turns off the inlining optimisation for code which has line numbers. We still inline things like the implicit "return None".
Break up COMPARE_OP into four logically distinct opcodes:
* COMPARE_OP for rich comparisons
* IS_OP for 'is' and 'is not' tests
* CONTAINS_OP for 'in' and 'is not' tests
* JUMP_IF_NOT_EXC_MATCH for checking exceptions in 'try-except' statements.
Document that lnotab can contain invalid bytecode offsets (because of
terrible reasons that are difficult to fix). Make dis.findlinestarts()
ignore invalid offsets in lnotab. All other uses of lnotab in CPython
(various reimplementations of addr2line or line2addr in Python, C and gdb)
already ignore this, because they take an address to look for, instead.
Add tests for the result of dis.findlinestarts() on wacky constructs in
test_peepholer.py, because it's the easiest place to add them.
Fix a regression introduced by af8646c805 that was causing code of the form:
if True and False:
do_something()
to be optimized incorrectly, eliminating the block.
The peephole optimizer was not optimizing correctly bytecode after negative deltas were introduced. This is due to the fact that some special values (255) were being searched for in both instruction pointer delta and line number deltas.
It no longer spends much time doing complex calculations and no
longer consumes much memory for creating large constants that will
be dropped later.
This fixes also bpo-21074.
* Constant statements will be ignored and the compiler will emit a
SyntaxWarning.
* Replace constant statement (ex: "1") with an expression statement
(ex: "x=1").
* test_traceback: use context manager on the file.
Issue #26204.
I have compared output between pre- and post-patch runs of these tests
to make sure there's nothing missing and nothing broken, on both
Windows and Linux. The only differences I found were actually tests
that were previously *not* run.
Irit Katriel
Brandt Bucher
Dennis Sweeney
Brandt Bucher
Serhiy Storchaka
Mark Shannon
T. Wouters
Joannah Nanjekye
Victor Stinner
Pablo Galindo
Victor Stinner
Zachary Ware
Nick Coghlan
Ezio Melotti
Martin v. Löwis
Mark Dickinson
Raymond Hettinger
Antoine Pitrou
Benjamin Peterson