| paul@472 | 1 | Name usage types: as parameters, as base classes, as callables. This potentially restricts
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| paul@472 | 2 | attribute usage effects because names mentioned as base classes are not propagated and
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| paul@472 | 3 | made freely available for use in attribute accesses.
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| paul@472 | 4 |
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| paul@419 | 5 | Low-Level Instructions and Macro Instructions
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| paul@419 | 6 | =============================================
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| paul@419 | 7 |
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| paul@429 | 8 | Have contexts and values stored separately in memory. This involves eliminating DataValue
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| paul@429 | 9 | and storing attributes using two words.
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| paul@429 | 10 |
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| paul@419 | 11 | Migrate macro instructions such as the *Index instructions to library code implemented
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| paul@419 | 12 | using low-level instructions.
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| paul@419 | 13 |
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| paul@419 | 14 | Consider introducing classic machine level instructions (word addition, subtraction, and
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| paul@419 | 15 | so on) in order to implement all current RSVP instructions.
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| paul@419 | 16 |
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| paul@450 | 17 | Move common code sequences to a library routine, such as the context checking that occurs
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| paul@450 | 18 | in functions and methods.
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| paul@450 | 19 |
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| paul@464 | 20 | Dataflow Optimisations
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| paul@464 | 21 | ======================
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| paul@450 | 22 |
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| paul@464 | 23 | Assignments, particularly now that no result register exists, may cause StoreTemp/LoadTemp
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| paul@464 | 24 | instruction pairs to be produced and these could be eliminated.
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| paul@450 | 25 |
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| paul@417 | 26 | Class and Module Attribute Assignment
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| paul@417 | 27 | =====================================
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| paul@417 | 28 |
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| paul@417 | 29 | Verify that the context information is correctly set, particularly for the unoptimised
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| paul@417 | 30 | cases.
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| paul@417 | 31 |
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| paul@417 | 32 | Update docs/assignment.txt.
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| paul@417 | 33 |
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| paul@431 | 34 | Prevent assignments within classes, such as method aliasing, from causing the source of an
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| paul@431 | 35 | assignment from being automatically generated. Instead, only external references should be
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| paul@431 | 36 | registered.
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| paul@431 | 37 |
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| paul@431 | 38 | Prevent "from <module> import ..." statements from registering references to such local
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| paul@431 | 39 | aliases such that they cause the source of each alias to be automatically generated.
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| paul@431 | 40 |
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| paul@419 | 41 | Consider attribute assignment observations, along with the possibility of class and module
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| paul@419 | 42 | attribute assignment.
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| paul@419 | 43 |
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| paul@419 | 44 | (Note direct assignments as usual, indirect assignments via the attribute usage
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| paul@419 | 45 | mechanism. During attribute collection and inference, add assigned values to all
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| paul@419 | 46 | inferred targets.)
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| paul@419 | 47 |
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| paul@419 | 48 | (Since class attributes can be assigned, StoreAttrIndex would no longer need to reject
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| paul@419 | 49 | static attributes, although this might still be necessary where attribute usage analysis
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| paul@419 | 50 | has not been performed.)
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| paul@419 | 51 |
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| paul@419 | 52 | Potentially consider changing static attribute details to use object-relative offsets in
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| paul@419 | 53 | order to simplify the instruction implementations. This might allow us to eliminate the
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| paul@419 | 54 | static attribute flag for attributes in the object table, at least at run-time.
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| paul@419 | 55 |
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| paul@413 | 56 | Dynamic Attribute Access
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| paul@413 | 57 | ========================
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| paul@413 | 58 |
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| paul@425 | 59 | Consider explicit accessor initialisation:
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| paul@425 | 60 |
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| paul@425 | 61 | attr = accessor("attr")
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| paul@425 | 62 | getattr(C, attr)
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| paul@413 | 63 |
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| paul@394 | 64 | Attribute Usage
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| paul@394 | 65 | ===============
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| paul@394 | 66 |
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| paul@498 | 67 | To consider: is it useful to distinguish between attribute name sets when the same names
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| paul@498 | 68 | are mentioned, but where one path through the code sets different values on attributes
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| paul@498 | 69 | than another? The _attrtypes collapses observations in order to make a list of object
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| paul@498 | 70 | types for a name, and the final set of names leading to such type deductions might be a
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| paul@498 | 71 | useful annotation to be added alongside _attrcombined.
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| paul@498 | 72 |
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| paul@498 | 73 | Interface/Type Generalisation
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| paul@498 | 74 | -----------------------------
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| paul@498 | 75 |
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| paul@480 | 76 | Consolidate interface observations by taking all cached table accesses and determining
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| paul@480 | 77 | which usage patterns lead to the same types. For example, if full usage of {a, b} and
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| paul@480 | 78 | {a, b, c} leads to A and B in both cases, either {a, b} can be considered as partial usage
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| paul@480 | 79 | of the complete interface {a, b, c}, or the latter can be considered as an
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| paul@480 | 80 | overspecification of the former.
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| paul@480 | 81 |
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| paul@364 | 82 | Consider type deduction and its consequences where types belong to the same hierarchy
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| paul@364 | 83 | and where a guard could be generated for the most general type.
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| paul@364 | 84 |
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| paul@364 | 85 | Consider permitting multiple class alternatives where the attributes are all identical.
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| paul@364 | 86 |
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| paul@360 | 87 | Support class attribute positioning similar to instance attribute positioning, potentially
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| paul@360 | 88 | (for both) based on usage observations. For example, if __iter__ is used on two classes,
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| paul@360 | 89 | the class attribute could be exposed at a similar relative position to the class (and
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| paul@360 | 90 | potentially accessible using a LoadAttr-style instruction).
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| paul@360 | 91 |
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| paul@394 | 92 | **** Constant attribute users need not maintain usage since they are already resolved. ****
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| paul@394 | 93 |
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| paul@498 | 94 | Self-related Usage
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| paul@498 | 95 | ------------------
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| paul@498 | 96 |
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| paul@498 | 97 | Usage of self to restrict attribute usage observations and coverage.
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| paul@498 | 98 |
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| paul@498 | 99 | Perform attribute usage on attributes of self as names, potentially combining observations
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| paul@498 | 100 | across methods.
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| paul@498 | 101 |
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| paul@498 | 102 | Additional Guards
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| paul@498 | 103 | -----------------
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| paul@498 | 104 |
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| paul@498 | 105 | Consider handling branches of values within namespaces in order to support more precise value usage.
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| paul@498 | 106 |
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| paul@498 | 107 | Loop entry points and other places where usage becomes more specific might be used as
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| paul@498 | 108 | places to impose guards. See tests/attribute_access_type_restriction_loop_list.py for an
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| paul@498 | 109 | example. (Such information is already shown in the reports.)
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| paul@498 | 110 |
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| paul@498 | 111 | Strict Interfaces/Types
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| paul@498 | 112 | -----------------------
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| paul@498 | 113 |
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| paul@498 | 114 | Make the gathering of usage parameterisable according to the optimisation level so that a
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| paul@498 | 115 | choice can be made between control-flow-dependent observations and the simple collection
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| paul@498 | 116 | of all attributes used with a name (producing a more static interface observation).
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| paul@498 | 117 |
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| paul@498 | 118 | AttributeError
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| paul@498 | 119 | --------------
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| paul@498 | 120 |
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| paul@504 | 121 | Consider attribute usage observations being suspended or optional inside blocks where
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| paul@504 | 122 | AttributeError may be caught (although this doesn't anticipate such exceptions being
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| paul@504 | 123 | caught outside a function altogether). For example:
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| paul@504 | 124 |
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| paul@504 | 125 | y = a.y
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| paul@504 | 126 | try:
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| paul@504 | 127 | z = a.z # z is an optional attribute
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| paul@504 | 128 | except AttributeError:
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| paul@504 | 129 | z = None
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| paul@498 | 130 |
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| paul@498 | 131 | Instantiation Deduction
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| paul@498 | 132 | -----------------------
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| paul@498 | 133 |
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| paul@394 | 134 | Consider handling CallFunc in micropython.inspect in order to produce instances of specific classes.
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| paul@503 | 135 | Then, consider adding support for guard removal/verification where known instances are involved. For
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| paul@503 | 136 | example:
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| paul@503 | 137 |
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| paul@503 | 138 | l = []
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| paul@503 | 139 | l.append(123) # type deductions are filtered using instantiation knowledge
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| paul@394 | 140 |
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| paul@394 | 141 | Frame Optimisations
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| paul@394 | 142 | ===================
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| paul@394 | 143 |
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| paul@394 | 144 | Stack frame replacement where a local frame is unused after a call, such as in a tail call
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| paul@394 | 145 | situation.
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| paul@394 | 146 |
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| paul@394 | 147 | Local assignment detection plus frame re-use. Example: slice.__init__ calls
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| paul@394 | 148 | xrange.__init__ with the same arguments which are unchanged in xrange.__init__. There is
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| paul@419 | 149 | therefore no need to build a new frame for this call, although in some cases the locals
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| paul@419 | 150 | frame might need expanding.
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| paul@419 | 151 |
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| paul@456 | 152 | Reference tracking where objects associated with names are assigned to attributes of other
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| paul@456 | 153 | objects may assist in allocation optimisations. Recording whether an object referenced by
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| paul@456 | 154 | a name is assigned to an attribute, propagated to another name and assigned to an
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| paul@456 | 155 | attribute, or passed to another function or method might, if such observations were
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| paul@456 | 156 | combined, allow frame-based or temporary allocation to occur.
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| paul@456 | 157 |
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| paul@472 | 158 | Instantiation
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| paul@472 | 159 | =============
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| paul@472 | 160 |
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| paul@472 | 161 | Specific instances could be produced, providing type information and acting somewhat like
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| paul@472 | 162 | classes during inspection.
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| paul@472 | 163 |
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| paul@419 | 164 | Inlining
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| paul@419 | 165 | ========
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| paul@419 | 166 |
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| paul@419 | 167 | Where a function or method call can always be determined, the body of the target could be
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| paul@419 | 168 | inlined - copied into place - within the caller. If the target is only ever called by a
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| paul@456 | 169 | single caller it could be moved into place. This could enhance deductions based on
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| paul@456 | 170 | attribute usage since observations from the inlined function would be merged into the
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| paul@456 | 171 | caller.
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| paul@394 | 172 |
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| paul@394 | 173 | Function Specialisation
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| paul@394 | 174 | =======================
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| paul@394 | 175 |
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| paul@394 | 176 | Specialisation of certain functions, such as isinstance(x, cls) where cls is a known
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| paul@394 | 177 | constant.
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| paul@394 | 178 |
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| paul@394 | 179 | Structure and Object Table Optimisations
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| paul@394 | 180 | ========================================
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| paul@394 | 181 |
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| paul@394 | 182 | Fix object table entries for attributes not provided by any known object, or provide an
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| paul@394 | 183 | error, potentially overridden by options. For example, the augmented assignment methods
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| paul@394 | 184 | are not supported by the built-in objects and thus the operator module functions cause
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| paul@394 | 185 | the compilation to fail. Alternatively, just supply the methods since something has to do
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| paul@394 | 186 | so in the builtins.
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| paul@394 | 187 |
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| paul@394 | 188 | Consider attribute merging where many attributes are just aliases for the same underlying
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| paul@394 | 189 | definition.
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| paul@394 | 190 |
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| paul@349 | 191 | Consider references to defaults as occurring only within the context of a particular
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| paul@349 | 192 | function, thus eliminating default value classes if such functions are not themselves
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| paul@349 | 193 | invoked.
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| paul@349 | 194 |
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| paul@394 | 195 | Scope Handling
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| paul@394 | 196 | ==============
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| paul@394 | 197 |
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| paul@394 | 198 | Consider merging the InspectedModule.store tests with the scope conflict handling.
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| paul@394 | 199 |
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| paul@343 | 200 | Consider labelling _scope on assignments and dealing with the assignment of removed
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| paul@343 | 201 | attributes, possibly removing the entire assignment, and distinguishing between such cases
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| paul@343 | 202 | and unknown names.
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| paul@343 | 203 |
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| paul@342 | 204 | Check name origin where multiple branches could yield multiple scope interpretations:
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| paul@342 | 205 |
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| paul@504 | 206 | try:
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| paul@504 | 207 | set # built-in name
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| paul@504 | 208 | except NameError:
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| paul@504 | 209 | from sets import Set as set # local definition of name
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| paul@342 | 210 |
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| paul@504 | 211 | set # could be confused by the local definition at run-time
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| paul@342 | 212 |
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| paul@394 | 213 | Object Coverage
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| paul@394 | 214 | ===============
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| paul@394 | 215 |
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| paul@332 | 216 | Support __init__ traversal (and other implicit names) more effectively.
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| paul@332 | 217 |
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| paul@499 | 218 | Importing Modules
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| paul@499 | 219 | =================
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| paul@499 | 220 |
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| paul@499 | 221 | Consider supporting relative imports, even though this is arguably a misfeature.
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| paul@499 | 222 |
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| paul@394 | 223 | Other
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| paul@394 | 224 | =====
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| paul@394 | 225 |
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| paul@482 | 226 | Consider a separate annotation phase where deductions are added to the AST for the
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| paul@482 | 227 | benefit of both the reporting and code generation phases.
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| paul@482 | 228 |
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| paul@449 | 229 | Support self attribute visualisation in the reports and/or provide a function or
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| paul@449 | 230 | annotations which can provide the eventual optimisation directly to such components.
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| paul@408 | 231 |
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| paul@332 | 232 | Check context_value initialisation (avoiding or handling None effectively).
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| paul@332 | 233 |
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| paul@342 | 234 | Consider better "macro" support where new expressions need to be generated and processed.
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| paul@402 | 235 |
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| paul@402 | 236 | Detect TestIdentity results involving constants, potentially optimising status-affected
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| paul@402 | 237 | instructions:
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| paul@402 | 238 |
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| paul@402 | 239 | TestIdentity(x, y) # where x is always y
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| paul@402 | 240 | JumpIfFalse(...) # would be removed (never false)
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| paul@402 | 241 | JumpIfTrue(...) # changed to Jump(...)
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| paul@402 | 242 |
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| paul@402 | 243 | Status-affected blocks could be optimised away for such constant-related results.
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