2 * MATLAB source -> numbl's JIT IR, ready for the WGSL backend.
3 *
4 * A model file defines ordinary MATLAB functions; the host specializes the ones
5 * it needs (`init`, `step`) for the concrete argument types of the current grid.
6 * This is exactly how numbl drives its own JIT — the caller supplies argument
7 * types, and lowering fixes every type and shape from there.
8 *
9 * Driving it through function signatures rather than injected scope means the
10 * .m declares what it needs: each parameter name is matched against what the
11 * host offers, and a name the host does not provide is a compile error rather
12 * than a silently undefined variable.
13 *
14 * Two numbl passes matter here:
15 * - `specializeUserFunction` lowers one function to IR, one statement per
16 * operation (ANF), with every node's type fixed.
17 * - `inlinePass` then folds single-use temps back into their consumer, so a
18 * source line like `fu = a - u + u.*u.*v` becomes ONE statement whose RHS is
19 * an expression tree — i.e. one GPU kernel instead of four.
20 */
21import { parseMFile } from 'numbl-src/numbl-core/parser/index.ts';
22import { Workspace, Lowerer, tensorDouble, scalarDouble } from 'numbl-src/numbl-core/jit/index.ts';
23import { specializeUserFunction } from 'numbl-src/numbl-core/jit/lowering/specialize.ts';
24import { inlinePass } from 'numbl-src/numbl-core/jit/codegen/inlinePass.ts';
25import type { IRFunc, IRStmt } from 'numbl-src/numbl-core/jit/lowering/ir.ts';
26import type { Type } from 'numbl-src/numbl-core/jit/lowering/types.ts';
27import { externalOpFiles, type GridSizes } from './externals.ts';
28import { ModelCompileError } from './errors.ts';
30/** What the host can supply for an argument the .m declares. */
31export type Binding =
32 /** An array, passed in a GPU buffer. */
33 | { kind: 'tensor'; shape: number[] }
34 /** A tunable scalar. Deliberately carries no exact value: an exact scalar
35 * would be constant-folded into the kernels, so moving a slider would force
36 * a recompile instead of just rewriting a uniform. */
37 | { kind: 'param' }
38 /** A fixed scalar, exact so array constructors reading it keep static
39 * shapes. */
40 | { kind: 'const'; value: number };
42const typeOf = (b: Binding): Type => {
43 switch (b.kind) {
44 case 'tensor':
45 return tensorDouble(b.shape);
46 case 'param':
47 return scalarDouble('unknown');
48 case 'const':
49 // Carry the sign too: numbl's sign lattice decides, for instance,
50 // whether sqrt() of a value can go complex.
51 return scalarDouble(
52 b.value > 0 ? 'positive' : b.value < 0 ? 'negative' : 'zero',
53 b.value,
54 );
55 }
56};
58/** One specialized function, as the planner consumes it. */
59export interface CompiledFunction {
60 name: string;
61 /** Declared arguments, in order, with the cName each lowered to. */
62 params: { name: string; cName: string; binding: Binding }[];
63 /** Requested outputs, in order, with the cName holding each result. */
64 outputs: { name: string; cName: string; ty: Type }[];
65 /** The lowered body. Read this only after `finish()`: the inline pass
66 * REPLACES the statement array rather than mutating it, so this is a live
67 * view of the function rather than a snapshot. */
68 readonly body: IRStmt[];
69}
71/** The shape of a `function` statement in numbl's AST. */
72interface FunctionDecl {
73 type: 'Function';
74 name: string;
75 params: string[];
76 outputs: string[];
77}
79/**
80 * A parsed model. Specialize the functions you need, then call `finish()` once
81 * — the inline pass rewrites every specialization together.
82 */
83export class CompiledModel {
84 #lowerer: Lowerer;
85 #decls: Map<string, FunctionDecl>;
86 #bindings: Record<string, Binding>;
88 constructor(
89 source: string,
90 bindings: Record<string, Binding>,
91 grid: GridSizes,
92 fileName = 'model.m',
93 ) {
94 const ast = parseMFile(source, fileName);
95 const ws = new Workspace(fileName, []);
96 ws.addFile({ name: fileName, source, ast });
97 // synth / analys become resolvable, with their type rules.
98 for (const f of externalOpFiles(grid)) ws.addFile(f);
99 ws.finalize();
101 this.#bindings = bindings;
102 this.#lowerer = new Lowerer(ws);
103 this.#decls = new Map();
104 for (const stmt of ast.body as { type: string }[]) {
105 if (stmt.type === 'Function') {
106 const fn = stmt as unknown as FunctionDecl;
107 this.#decls.set(fn.name, fn);
108 }
109 }
110 }
112 /** Names of the functions the file defines. */
113 functionNames(): string[] {
114 return [...this.#decls.keys()];
115 }
117 /**
118 * Lower `name` for the current bindings, requesting `nargout` outputs.
119 * Every declared parameter must name something the host provides.
120 */
121 specialize(name: string, nargout: number): CompiledFunction {
122 const decl = this.#decls.get(name);
123 if (!decl) {
124 const defined = this.functionNames();
125 throw new ModelCompileError(
126 `the model must define a function named '${name}'` +
127 (defined.length
128 ? ` (it defines ${defined.map((n) => `'${n}'`).join(', ')})`
129 : ' (it defines no functions)'),
130 );
131 }
132 if (decl.outputs.length < nargout) {
133 throw new ModelCompileError(
134 `'${name}' must return ${nargout} value${nargout === 1 ? '' : 's'}, ` +
135 `but declares ${decl.outputs.length}`,
136 );
137 }
139 const bindings = decl.params.map((p) => {
140 const b = this.#bindings[p];
141 if (!b) {
142 const offered = Object.keys(this.#bindings).join(', ');
143 throw new ModelCompileError(
144 `'${name}' takes an argument named '${p}', which this app does not ` +
145 `provide. Available: ${offered}.`,
146 );
147 }
148 return b;
149 });
151 const fn: IRFunc = specializeUserFunction.call(
152 this.#lowerer,
153 decl,
154 bindings.map(typeOf),
155 undefined,
156 undefined,
157 undefined,
158 nargout,
159 undefined,
160 );
162 return {
163 name,
164 params: fn.params.map((p, i) => ({
165 name: p,
166 cName: fn.cParams[i],
167 binding: bindings[i],
168 })),
169 outputs: fn.outputs.slice(0, nargout).map((o, i) => ({
170 name: o,
171 cName: fn.cOutputs[i],
172 ty: fn.outputTypes[i],
173 })),
174 // A getter, not a snapshot: `finish()` runs after every specialization
175 // and swaps in a rewritten statement array.
176 get body() {
177 return fn.body;
178 },
179 };
180 }
182 /**
183 * Run the inline pass over everything specialized so far. It rewrites the
184 * function bodies in place, so `CompiledFunction`s handed out earlier are
185 * updated too.
186 */
187 finish(): void {
188 inlinePass({ topLevelStmts: [], functions: this.#lowerer.specializations });
189 }
190}