Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | 466x 466x 466x 466x 1753x 1753x 154x 154x 1907x 1907x 67x 67x 83x 83x 83x 66x 66x 38x 38x 32x 32x 1x 1x 31x 9x 1907x 1907x 1907x 627x 544x 544x 83x 83x 1907x 83x 83x 83x 83x 99x 83x 466x 466x 466x 466x | /**
* ADR-036 constant index bounds: E0854.
*
* #1322. Two throws in `TypeValidator.checkArrayBounds`, reached from three
* codegen paths -- an assignment target, a multi-dimensional target, and (since
* #1360) a subscript in value position -- all reporting `1:0` with the line
* smuggled into the message text.
*
* ## What is subscripted, at each subscript
*
* `grid[i][9]` is bounded by the shape of `grid[i]`, not of `grid`, so the
* question at every subscript is "what is the type of the chain before it".
* That is the one operand typer's chain walk (#1668), the same for an
* expression and an assignment target, where codegen once resolved the
* array's name three different ways (bare, scope-resolved, and "root or
* resolved identifier"). Its dimensions are 1.4's, folded where the array is
* declared, so a local `const N <- 2` sizes `u8[N] buf` at 2 (#1664 box 7).
*
* ## One hole closed, probed
*
* `s.data[9]` with `u8[4] data` a struct field was never checked, read or
* written: codegen bounded the ROOT variable's dimensions and `s` has none.
* The prefix walk carries a field's dimensions, so a field is bounded like a
* variable.
*
* ## What stays silent
*
* A runtime index; a dimension this pass cannot size (a C macro); a subscript
* with no dimension left, which is a bit index and another rule's; and a
* two-expression subscript, which is a slice or a bit range (ADR-007).
*/
import { ParserRuleContext, ParseTreeWalker } from "antlr4ng";
import { CNextListener } from "../../PARSE/2-Parse/grammar/CNextListener";
import * as Parser from "../../PARSE/2-Parse/grammar/CNextParser";
import ParserUtils from "../../utils/ParserUtils";
import OperandTyper from "../../utils/OperandTyper";
import IArrayIndexBoundsError from "./types/IArrayIndexBoundsError";
import ConstantExpression from "./helpers/ConstantExpression";
import type IAnalysisContext from "./types/IAnalysisContext";
import type IOperandType from "../../types/IOperandType";
/** One subscript in a chain: its expressions, and how many ops follow it. */
interface ISubscript {
readonly expressions: readonly Parser.ExpressionContext[];
readonly opsAfter: number;
readonly dimension: number;
readonly at: ParserRuleContext;
}
class ArrayIndexBoundsListener extends CNextListener {
private readonly found: IArrayIndexBoundsError[] = [];
public constructor(private readonly context: IAnalysisContext) {
super();
}
public errors(): IArrayIndexBoundsError[] {
return this.found;
}
override enterPostfixExpression = (
ctx: Parser.PostfixExpressionContext,
): void => {
this.checkChain(ctx, ctx.postfixOp());
};
override enterAssignmentTarget = (
ctx: Parser.AssignmentTargetContext,
): void => {
this.checkChain(ctx, ctx.postfixTargetOp());
};
/**
* Each subscript against the value it indexes, as the one operand typer
* typed the chain. A `this.`/`global.` root consumes its first `.name`, so
* the typer's steps are the chain's LAST ops, in order.
*/
private checkChain(
ctx: Parser.PostfixExpressionContext | Parser.AssignmentTargetContext,
ops: readonly (Parser.PostfixOpContext | Parser.PostfixTargetOpContext)[],
): void {
const subscripts = ArrayIndexBoundsListener.subscriptsOf(ops);
if (subscripts.length === 0) return;
const typing = OperandTyper.chainOf(ctx, this.context);
for (const subscript of subscripts) {
const step = typing.steps.at(-1 - subscript.opsAfter);
this.check(
subscript,
step?.before ?? null,
ArrayIndexBoundsListener.spelling(ctx, ops, subscript.opsAfter),
);
}
}
/** E0854 against the leading dimension of what the subscript indexes. */
private check(
subscript: ISubscript,
indexed: IOperandType | null,
name: string,
): void {
if (indexed === null || subscript.expressions.length !== 1) return;
// A dimension 1.4 could fold is a number; one it could not (a C macro)
// is left to the C compiler, as codegen's UNRESOLVED_DIMENSION was
const bound = indexed.dimensions[0];
if (typeof bound !== "number") return;
const index = ConstantExpression.valueAt(
subscript.expressions[0],
this.context,
);
if (index === null) return;
const { line, column } = ParserUtils.getPosition(subscript.at);
if (index < 0) {
this.found.push({
code: "E0854",
line,
column,
message: `Array index out of bounds: ${index} is negative for '${name}' dimension ${subscript.dimension}`,
helpText: "An index counts from zero (ADR-036).",
});
return;
}
if (bound > 0 && index >= bound) {
this.found.push({
code: "E0854",
line,
column,
message: `Array index out of bounds: ${index} >= ${bound} for '${name}' dimension ${subscript.dimension}`,
helpText: `The last valid index is ${bound - 1} (ADR-036).`,
});
}
}
/**
* Every one-or-two-expression subscript op in a chain, with the number of
* ops after it (so the prefix walk can stop before it) and which dimension
* of the current base it indexes (subscripts since the last member step).
*/
private static subscriptsOf(
ops: readonly (Parser.PostfixOpContext | Parser.PostfixTargetOpContext)[],
): ISubscript[] {
const found: ISubscript[] = [];
let depth = 0;
ops.forEach((op, index) => {
if (op.LBRACKET() === null) {
depth = 0;
return;
}
depth += 1;
found.push({
expressions: op.expression(),
opsAfter: ops.length - index - 1,
dimension: depth,
at: op,
});
});
return found;
}
/** The chain as written up to (not including) the op `opsAfter` from the end. */
private static spelling(
ctx: ParserRuleContext,
ops: readonly ParserRuleContext[],
opsAfter: number,
): string {
const keep = ops.length - opsAfter - 1;
const full = ctx.getText();
let cut = full.length;
for (let i = keep; i < ops.length; i += 1) {
cut -= ops[i].getText().length;
}
return full.slice(0, cut);
}
}
class ArrayIndexBoundsAnalyzer {
/** #1456: handed in rather than read off shared state. */
constructor(private readonly context: IAnalysisContext) {}
public analyze(tree: Parser.ProgramContext): IArrayIndexBoundsError[] {
const listener = new ArrayIndexBoundsListener(this.context);
ParseTreeWalker.DEFAULT.walk(listener, tree);
return listener.errors();
}
}
export default ArrayIndexBoundsAnalyzer;
|