In Python/bytecodes.c, you now write
```
DEOPT_IF(condition);
```
The code generator expands this to
```
DEOPT_IF(condition, opcode);
```
where `opcode` is the name of the unspecialized instruction.
This works inside macro expansions too.
**CAVEAT:** The entire `DEOPT_IF(condition)` statement must be on a single line.
If it isn't, the substitution will fail; an error will be printed by the code generator
and the C compiler will report some errors.
These are the most popular specializations of `LOAD_ATTR` and `STORE_ATTR`
that weren't already viable uops:
* Split LOAD_ATTR_METHOD_WITH_VALUES
* Split LOAD_ATTR_METHOD_NO_DICT
* Split LOAD_ATTR_SLOT
* Split STORE_ATTR_SLOT
* Split STORE_ATTR_INSTANCE_VALUE
Also:
* Add `-v` flag to code generator which prints a list of non-viable uops
(easter-egg: it can print execution counts -- see source)
* Double _Py_UOP_MAX_TRACE_LENGTH to 128
I had dropped one of the DEOPT_IF() calls! :-(
This makes the internal representation in the code generator simpler: there's a list of ops, and a list of macros, and there's no special-casing needed for ops that aren't macros. (There's now special-casing for ops that are also macros, but that's simpler.)
* Rename SAVE_IP to _SET_IP
* Rename EXIT_TRACE to _EXIT_TRACE
* Rename SAVE_CURRENT_IP to _SAVE_CURRENT_IP
* Rename INSERT to _INSERT (This is for Ken Jin's abstract interpreter)
* Rename IS_NONE to _IS_NONE
* Rename JUMP_TO_TOP to _JUMP_TO_TOP
Also remove NOP instructions.
The "stubs" are not optimized in this fashion (their SAVE_IP should always be preserved since it's where to jump next, and they don't contain NOPs by their nature).
This finishes the work begun in gh-107760. When, while projecting a superblock, we encounter a call to a short, simple function, the superblock will now enter the function using `_PUSH_FRAME`, continue through it, and leave it using `_POP_FRAME`, and then continue through the original code. Multiple frame pushes and pops are even possible. It is also possible to stop appending to the superblock in the middle of a called function, when running out of space or encountering an unsupported bytecode.
This fixes two tiny defects in analysis.py that I didn't catch on time in #107564:
- `get_var_names` in `check_macro_consistency` should skip `UNUSED` names.
- Fix an occurrence of `is UNUSED` (should be `==`).
Introducing a new file, stacking.py, that takes over several responsibilities related to symbolic evaluation of push/pop operations, with more generality.
This mostly extracts a whole bunch of stuff out of generate_cases.py into separate files, but there are a few other things going on here.
- analysis.py: `Analyzer` etc.
- instructions.py: `Instruction` etc.
- flags.py: `InstructionFlags`, `variable_used`, `variable_used_unspecialized`
- formatting.py: `Formatter` etc.
- Rename parser.py to parsing.py, to avoid conflict with stdlib parser.py
- Blackify most things
- Fix most mypy errors
- Remove output filenames from Generator state, add them to `write_instructions()` etc.
- Fix unit tests
Guido van Rossum
Irit Katriel
Alex Waygood