Appearance
| 1 | namespace Semantic is | |
| 2 | use Source.LOCATION | |
| 3 | ||
| 4 | use Collections.LIST | |
| 5 | ||
| 6 | // A line-oriented trace of what type inference does inside each | |
| 7 | // function body, written when --trace-inference names stderr, | |
| 8 | // --trace-inference-file names a file, or GHUL_TRACE_INFERENCE is set | |
| 9 | // (to a path, or to `-` or nothing for stderr). With tracing off | |
| 10 | // nothing is formatted and nothing is written. | |
| 11 | // | |
| 12 | // Each line is an event name followed by tab-separated fields. The | |
| 13 | // second field places the event: `<body>.<walk>` inside a body's | |
| 14 | // outer walk, `<body>` for a body boundary, `-` outside any body. | |
| 15 | // Body numbers count bodies in the order compile-expressions reaches | |
| 16 | // them, so two compilers given the same input produce traces that | |
| 17 | // can be diffed line by line. | |
| 18 | // | |
| 19 | // body-begin a function body's walks start | |
| 20 | // walk-begin one outer walk of the body starts | |
| 21 | // mint a placeholder is created for a type argument slot | |
| 22 | // lower-bound a lower bound is offered to an inference variable | |
| 23 | // upper-bound an upper bound is offered to an inference variable | |
| 24 | // constraint an operation constraint is offered to a placeholder | |
| 25 | // rewalk a local site rolls back and walks a subtree again | |
| 26 | // error an error is reported, rolled back later or not | |
| 27 | // obligation a rule waits on a placeholder instead of firing | |
| 28 | // walk-end the walk finished: clean, and whether it made progress | |
| 29 | // body-end the body's walks stopped, and why | |
| 30 | class INFERENCE_TRACE is | |
| 31 | enabled: bool static | |
| 32 | ||
| 33 | _writer: IO.TextWriter? static | |
| 34 | ||
| 35 | _bodies: LIST[int] static | |
| 36 | _walks: LIST[int] static | |
| 37 | _next_body: int static | |
| 38 | ||
| 39 | init() static is | |
| 40 | _bodies = LIST[int]() | |
| 41 | _walks = LIST[int]() | |
| 42 | ||
| 43 | let target = System.Environment.get_environment_variable("GHUL_TRACE_INFERENCE") | |
| 44 | ||
| 45 | if target? then | |
| 46 | enable(target) | |
| 47 | fi | |
| 48 | si | |
| 49 | ||
| 50 | // `-` or an empty target writes to stderr; anything else is a | |
| 51 | // file path, truncated so one build gives one trace. | |
| 52 | enable(target: string) static is | |
| 53 | if target =~ "" \/ target =~ "-" then | |
| 54 | _writer = IO.Std.error | |
| 55 | else | |
| 56 | let writer = IO.StreamWriter(target, false) | |
| 57 | writer.auto_flush = true | |
| 58 | _writer = writer | |
| 59 | fi | |
| 60 | ||
| 61 | Logging.DIAGNOSTIC_TRACE.on_error = (location: LOCATION, message: string) -> void => _write("error\t{_where()}\tat={location}\t{message}") | |
| 62 | ||
| 63 | enabled = true | |
| 64 | si | |
| 65 | ||
| 66 | begin_body(function: Symbols.Function?, location: LOCATION) -> int static is | |
| 67 | if !enabled then | |
| 68 | return -1 | |
| 69 | fi | |
| 70 | ||
| 71 | let id = _next_body | |
| 72 | _next_body = _next_body + 1 | |
| 73 | ||
| 74 | _bodies.add(id) | |
| 75 | _walks.add(0) | |
| 76 | ||
| 77 | _write("body-begin\t{id}\tfunction={_function_name(function)}\tat={location}") | |
| 78 | ||
| 79 | return id | |
| 80 | si | |
| 81 | ||
| 82 | begin_walk(walk: int) static is | |
| 83 | if !enabled \/ _walks.count == 0 then | |
| 84 | return | |
| 85 | fi | |
| 86 | ||
| 87 | _walks[_walks.count - 1] = walk | |
| 88 | ||
| 89 | _write("walk-begin\t{_where()}") | |
| 90 | si | |
| 91 | ||
| 92 | end_walk(clean: bool, progress: bool) static is | |
| 93 | if !enabled \/ _walks.count == 0 then | |
| 94 | return | |
| 95 | fi | |
| 96 | ||
| 97 | _write("walk-end\t{_where()}\tclean={clean}\tprogress={progress}") | |
| 98 | si | |
| 99 | ||
| 100 | // `limit` is the most walks a body is allowed: stopping there | |
| 101 | // while still making progress is giving up rather than settling. | |
| 102 | end_body(id: int, walks: int, limit: int, clean: bool, progress: bool) static is | |
| 103 | if !enabled \/ _bodies.count == 0 then | |
| 104 | return | |
| 105 | fi | |
| 106 | ||
| 107 | // A body whose walk threw leaves its entry behind; drop it. | |
| 108 | while _bodies.count > 1 /\ _bodies[_bodies.count - 1] != id do | |
| 109 | _pop() | |
| 110 | od | |
| 111 | ||
| 112 | let outcome = | |
| 113 | if clean then "clean" | |
| 114 | elif !progress then "errors-without-progress" | |
| 115 | elif walks >= limit then "gave-up" | |
| 116 | else "stopped" | |
| 117 | fi | |
| 118 | ||
| 119 | _write("body-end\t{id}\twalks={walks}\toutcome={outcome}") | |
| 120 | ||
| 121 | _pop() | |
| 122 | si | |
| 123 | ||
| 124 | mint(container: Symbols.Symbol, slot: string, phantom: Symbols.Variable, location: LOCATION, function: Symbols.Function?) static is | |
| 125 | if !enabled then | |
| 126 | return | |
| 127 | fi | |
| 128 | ||
| 129 | _write("mint\t{_where()}\tcontainer={container.qualified_name}\tslot={slot}\tphantom={phantom.name}\tat={location}\tin={_function_name(function)}") | |
| 130 | si | |
| 131 | ||
| 132 | rewalk(site: string, kind: string) static is | |
| 133 | if !enabled then | |
| 134 | return | |
| 135 | fi | |
| 136 | ||
| 137 | _write("rewalk\t{_where()}\tsite={site}\tkind={kind}") | |
| 138 | si | |
| 139 | ||
| 140 | obligation(rule: string, awaiting: Types.Type, location: Source.LOCATION?) static is | |
| 141 | if !enabled then | |
| 142 | return | |
| 143 | fi | |
| 144 | ||
| 145 | let target = | |
| 146 | if let placeholder: Types.INFERRED_VARIABLE_TYPE = awaiting then | |
| 147 | placeholder.origin.name | |
| 148 | else | |
| 149 | awaiting.to_string() | |
| 150 | fi | |
| 151 | ||
| 152 | _write("obligation\t{_where()}\trule={rule}\ttarget={target}\tat={location}") | |
| 153 | si | |
| 154 | ||
| 155 | add_lower_bound(site: string, target: Symbols.Variable, bound: Types.Type?) -> bool static is | |
| 156 | let added = target.add_lower_bound(bound) | |
| 157 | ||
| 158 | if added then | |
| 159 | OBLIGATIONS.note_learned() | |
| 160 | fi | |
| 161 | ||
| 162 | if enabled then | |
| 163 | _offered("lower-bound", site, target, _type_name(bound), added) | |
| 164 | fi | |
| 165 | ||
| 166 | return added | |
| 167 | si | |
| 168 | ||
| 169 | add_upper_bound(site: string, target: Symbols.Variable, bound: Types.Type?) -> bool static is | |
| 170 | let added = target.add_upper_bound(bound) | |
| 171 | ||
| 172 | if added then | |
| 173 | OBLIGATIONS.note_learned() | |
| 174 | fi | |
| 175 | ||
| 176 | if enabled then | |
| 177 | _offered("upper-bound", site, target, _type_name(bound), added) | |
| 178 | fi | |
| 179 | ||
| 180 | return added | |
| 181 | si | |
| 182 | ||
| 183 | add_constraint(site: string, target: Symbols.Variable, constraint: Constraint?) -> bool static is | |
| 184 | let added = target.add_constraint(constraint) | |
| 185 | ||
| 186 | if added then | |
| 187 | OBLIGATIONS.note_learned() | |
| 188 | fi | |
| 189 | ||
| 190 | if enabled then | |
| 191 | _offered("constraint", site, target, if constraint? then constraint.to_string() else "null" fi, added) | |
| 192 | fi | |
| 193 | ||
| 194 | return added | |
| 195 | si | |
| 196 | ||
| 197 | _offered(event: string, site: string, target: Symbols.Variable, what: string, added: bool) static is | |
| 198 | _write("{event}\t{_where()}\tsite={site}\ttarget={target.name}\ttarget-at={target.location}\twhat={what}\tadded={added}") | |
| 199 | si | |
| 200 | ||
| 201 | _where() -> string static => | |
| 202 | if _bodies.count == 0 then | |
| 203 | "-" | |
| 204 | else | |
| 205 | "{_bodies[_bodies.count - 1]}.{_walks[_walks.count - 1]}" | |
| 206 | fi | |
| 207 | ||
| 208 | _pop() static is | |
| 209 | _bodies.remove_at(_bodies.count - 1) | |
| 210 | _walks.remove_at(_walks.count - 1) | |
| 211 | si | |
| 212 | ||
| 213 | _function_name(function: Symbols.Function?) -> string static => | |
| 214 | if function? then function.qualified_name else "-" fi | |
| 215 | ||
| 216 | _type_name(type: Types.Type?) -> string static => | |
| 217 | if type? then "{type}" else "null" fi | |
| 218 | ||
| 219 | _write(line: string) static is | |
| 220 | if let writer = _writer then | |
| 221 | writer.write_line(line) | |
| 222 | fi | |
| 223 | si | |
| 224 | si | |
| 225 | si |