Fix by Neil Schemenauer. Visit the Subscript node when trying to find
the operation for a statement.
XXX Not sure if there are other nodes that should be visited.
There are now no known cases where the compiler package computes a
stack depth lower than the one computed by the builtin compiler. (To
achieve this state, we had to fix bugs in both compilers :-).
The chief change is to do the depth calculations with respect to basic
blocks. The stack effect of block is calculated. Then the flow graph
is traversed using breadth-first search to find the max weight path
through the graph.
Had to fix the StackDepthTracker to calculate the right info for
several opcodes: LOAD_ATTR, CALL_FUNCTION (and friends), MAKE_CLOSURE,
and DUP_TOPX.
XXX Still need to handle free variables in MAKE_CLOSURE.
XXX There are still a lot of places where the computed stack depth is
larger than for the builtin compiler. These won't cause the
interpreter to overflow the frame, but they waste space.
compile() becomes replacement for builtin compile()
compileFile() generates a .pyc from a .py
both are exported in __init__
compiler.parse() gets optional second argument to specify compilation
mode, e.g. single, eval, exec
Add AbstractCompileMode as parent class and Module, Expression, and
Interactive as concrete subclasses. Each corresponds to a compilation
mode.
THe AbstractCompileMode instances in turn delegate to CodeGeneration
subclasses specialized for their particular functions --
ModuleCodeGenerator, ExpressionCodeGeneration,
InteractiveCodeGenerator.
Remove the only test in the syntax module. It ends up that the
transformer must handle this error case.
In the transformer, check for a list compression in com_assign_list()
by looking for a list_for node where a comma is expected.
In pycodegen.compile() re-raise the SyntaxError rather than catching
it and exiting
Invoke compiler.syntax.check() after building AST. If a SyntaxError
occurs, print the error and exit without generating a .pyc file.
Refactor code to use compiler.misc.set_filename() rather than passing
filename argument around to each CodeGenerator instance.
Remove the option to have nested scopes or old LGB scopes. This has a
large impact on the code base, by removing the need for two variants
of each CodeGenerator.
Add a get_module() method to CodeGenerator objects, used to get the
future features for the current module.
Set CO_GENERATOR, CO_GENERATOR_ALLOWED, and CO_FUTURE_DIVISION flags
as appropriate.
Attempt to fix the value of nlocals in newCodeObject(), assuming that
nlocals is 0 if CO_NEWLOCALS is not defined.
Fix list comp code generation -- emit GET_ITER instead of Const(0)
after the list.
Add CO_GENERATOR flag to generators.
Get CO_xxx flags from the new module
try/except or try/finally.
Previous versions had only track SETUP_LOOP blocks and ignored the
exception part. This meant that it allowed continue inside a
try/except but generated buggy code. Now it does the right thing.
As the doc string for _lookupName() explains:
This routine uses a list instead of a dictionary, because a
dictionary can't store two different keys if the keys have the
same value but different types, e.g. 2 and 2L. The compiler
must treat these two separately, so it does an explicit type
comparison before comparing the values.
Avoid if/elif/elif/else tests where the final else is supposed to
handle exactly one case instead of all other cases. When the list of
operators is extended, the catchall else treats all new operators as
the last operator in the set of tests. Instead, raise an exception if
an unexpected operator occurs.
Use a dictionary instead of a list to map objects to their offsets in
a const/name tuple of a code object.
XXX The conversion is perhaps incomplete, in that we shouldn't have to
do the list2dict to start.
Add support for floor division (// and //=)
The implementation of getChildren() and getChildNodes() is intended to
be faster, because it avoids calling flatten() on every return value.
But it's not clear that it is a lot faster, because constructing a
tuple with just the right values ends up being slow. (Too many
attribute lookups probably.)
The ast.txt file is much more complicated, with funny characters at
the ends of names (*, &, !) to indicate the types of each child node.
The astgen script is also much more complex, making me wonder if it's
still useful.
varnames should list all the local variables (with arguments first).
The XXX_NAME ops typically occur at the module level and assignment
ops should create locals.
(Hard to believe these were never handled before)
Add misc.mangle() that mangles based on the rules in compile.c.
XXX Need to test the corner cases
Update CodeGenerator with a class_name attribute bound to None. If a
particular instance is created within a class scope, the instance's
class_name is bound to that class's name.
Add mangle() method to CodeGenerator that mangles if the class_name
has a class_name in it.
Modify the FunctionCodeGenerator family to handle an extra argument--
the class_name.
Wrap all name ops and attrnames in calls to self.mangle()
Make nested scopes enabled by default
Add is_constant_false() helper so that compiled code and symbols are
consistent with builtin compiler's handling of "if 0:"
Fix doc string handling to be consistent with recent change that
eliminates the doc string from the Module's node attribute.
Add fix to print handling from Evan & Shane.
Track change to visitor api by making "verbose" explicit.
Comment out setting CO_NESTED flag (it's unnecessary in 2.2).
Evan Simpson's fix. And his explanation:
If you defined two nested functions in a row that refer to the
same non-global variable, the second one will be generated as
though the variable were global.
The use of com_node() introduces a lot of extra stack frames, enough
to cause a stack overflow compiling test.test_parser with the standard
interpreter recursionlimit. The com_node() is a convenience function
that hides the dispatch details, but comes at a very high cost. It is
more efficient to dispatch directly in the callers. In these cases,
use lookup_node() and call the dispatched node directly.
Also handle yield_stmt in a way that will work with Python 2.1
(suggested by Shane Hathaway)
Remove _preorder as alias for dispatch and call dispatch directly.
Add an extra optional argument to walk()
XXX Also comment out some code that does debugging prints.
Armin Rigo pointed out that the way the line-# table got built didn't work
for lines generating more than 255 bytes of bytecode. Fixed as he
suggested, plus corresponding changes to pyassem.py, plus added some
long overdue docs about this subtle table to compile.c.
Bugfix candidate (line numbers may be off in tracebacks under -O).
Always emit a SET_LINENO 0 at the beginning of the module. The
builtin compiler does this, and it's much easier to compare bytecode
generated by the two compilers if they both do.
Move the SET_LINENO inside the FOR_LOOP block for list
comprehensions. Also for compat. with builtin compiler.
Fix annoying bugs in flow graph layout code. In some cases the
implicit control transfers weren't honored. In other cases,
JUMP_FORWARD instructions jumped backwards.
Remove unused arg from nextBlock().
pycodegen.py
Add optional force kwarg to set_lineno() that will emit a
SET_LINENO even if it is the same as the previous lineno.
Use explicit LOAD_FAST and STORE_FAST to access list comp implicit
variables. (The symbol table doesn't know about them.)
Add mangling support
Add get_children() and add_child() methods to Scope
Skip nodes when If test is a false constant
Add test code that checks results against symtable module
Fix com_NEWLINE() so that is accepts arguments, which occurs for lines like:
stmt; # note trailing semicolon
Add XXX about checking for assignment to list comps
embedded code objects (e.g. functions) rather than the generated code
object. This change means that the compiler generates code for
everything at the end, rather then generating code for each function
as it finds it. Implementation note: _convert_LOAD_CONST in
pyassem.py must be change to call getCode().
Other changes follow. Several changes creates extra edges between
basic blocks to reflect control flow for loops and exceptions. These
missing edges had gone unnoticed because they do not affect the
current compilation process.
pyassem.py:
Add _enable_debug() and _disable_debug() methods that print
instructions and blocks to stdout as they are generated.
Add edges between blocks for instructions like SETUP_LOOP,
FOR_LOOP, etc.
Add pruneNext to get rid of bogus edges remaining after
unconditional transfer ops (e.g. JUMP_FORWARD)
Change repr of Block to omit block length.
pycodegen.py:
Make sure a new block is started after FOR_LOOP, etc.
Change assert implementation to use RAISE_VARARGS 1 when there is
no user-specified failure output.
misc.py:
Implement __contains__ and copy for Set.
Reformatting -- long lines, "[ ]" -> "[]", a few indentation nits.
Replace calls to Node function (which constructed ast nodes) with
calls to actual constructors imported from ast module.
Optimize com_node (most frequently used method) for the common case --
the appropriate method is found in _dispatch.
Fix com_augassign to use class object's rather than node names
(rendered invalid by recent changes to ast)
Remove expensive tests for sequence-ness in com_stmt and
com_append_stmt. These tests should never fail; if they do, something
is really broken and exception will be raised elsewhere.
Fix com_stmt and com_append_stmt to use isinstance rather than
testing's type slot of ast node (this slot disappeared with recent
changes to ast).
1.5.2. The compiler generates code for the version of the interpreter
it is run under.
ast.py:
Print and Printnl add dest attr for extended print
new node AugAssign for augmented assignments
new nodes ListComp, ListCompFor, and ListCompIf for list
comprehensions
pyassem.py:
add work around for string-Unicode comparison raising UnicodeError
on comparison of two objects in code object's const table
pycodegen.py:
define VERSION, the Python major version number
get magic number using imp.get_magic() instead of hard coding
implement list comprehensions, extended print, and augmented
assignment; augmented assignment uses Delegator classes (see
doc string)
fix import and tuple unpacking for 1.5.2
transformer.py:
various changes to support new 2.0 grammar and old 1.5 grammar
add debug_tree helper than converts and symbol and token numbers
to their names
Fix import support to work with import as variant of Python 2.0. The
grammar for import changed, requiring changes in transformer and code
generator, even to handle compilation of imports with as.
- fix tab space issues (SF patch #101167 by Neil Schemenauer)
- fix co_flags for classes to include CO_NEWLOCALS (SF patch #101145 by Neil)
- fix for merger of UNPACK_LIST and UNPACK_TUPLE into UNPACK_SEQUENCE,
(SF patch #101168 by, well, Neil :)
- Adjust bytecode MAGIC to current bytecode.
TODO: teach compile.py about list comprehensions.
Attached is a set of diffs for the .py compiler that adds support
for the new extended call syntax.
compiler/ast.py:
CallFunc node gets 2 new children to support extended call syntax -
"star_args" (for "*args") and "dstar_args" (for "**args")
compiler/pyassem.py
It appear that self.lnotab is supposed to be responsible for
tracking line numbers, but self.firstlineno was still hanging
around. Removed self.firstlineno completely. NOTE - I didnt
actually test that the generated code has the correct line numbers!!
Stack depth tracking appeared a little broken - the checks never
made it beyond the "self.patterns" check - thus, the custom methods
were never called! Fixed this.
(XXX Jeremy notes: I think this code is still broken because it
doesn't track stack effects across block bounaries.)
Added support for the new extended call syntax opcodes for depth
calculations.
compiler/pycodegen.py
Added support for the new extended call syntax opcodes.
compiler/transformer.py
Added support for the new extended call syntax.
code generator uses flowgraph as intermediate representation. the old
rep uses a list with explicit "StackRefs" to indicate the target
of jumps.
pyassem converts flowgraph to bytecode, breaks up individual steps of
generating bytecode
fix imports
remove parse functions and visitor code
track name change: Classdef to Class
add some comments and tweak order of visitXXX methods
get rid of if __name__ == "__main__ section
Jeremy Hylton
Martin v. Löwis
Tim Peters
Barry Warsaw
Andrew M. Kuchling
Thomas Wouters
Greg Stein