LabelTerminal scaffolding
Adds a new `LabelTerminal` which will be used to represent LabeledStatements that contain a statement other than a loop. What we do for these cases is basically break the containing block in two, with a goto after the inner statement to the fallthrough. This allows us to model the label, and any `break` to it, in the HIR. However this fails in codegen because we can't find the fallthrough branch — we need a high level terminal that knows about this structure. Hence LabelTerminal. Now, instead of just a continuation block and a goto, we have a structured terminal. The LabelTerminal expresses the block for the labeled statement and the continuation, and we can use this to put it back together when constructing a ReactiveFunction. Note that this PR is just the scaffolding for LabelTerminal, the next PR is the interesting bits.
Joe Savona committed
Apr 5, 2023 at 16:26 UTC
b087635e5db273309930ace018c58cf705989b45
6 files changed
+56
-1
compiler/forget/src/HIR/HIR.ts
+10
-1
@@ -269,7 +269,8 @@ export type Terminal =
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| WhileTerminal
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| LogicalTerminal
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| TernaryTerminal
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- | OptionalCallTerminal;
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+ | OptionalCallTerminal
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+ | LabelTerminal;
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/**
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* Terminal nodes allowed for a value block
@@ -379,6 +380,14 @@ export type TernaryTerminal = {
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loc: SourceLocation;
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};
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+export type LabelTerminal = {
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+ kind: "label";
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+ block: BlockId;
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+ fallthrough: BlockId | null;
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+ id: InstructionId;
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+ loc: SourceLocation;
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+};
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+
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export type OptionalCallTerminal = {
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kind: "optional-call";
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// Whether the call itself is optional. If false, this means that the callee itself
compiler/forget/src/HIR/HIRBuilder.ts
+4
@@ -667,6 +667,10 @@ export function reversePostorderBlocks(func: HIR): void {
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visit(terminal.init);
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break;
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}
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+ case "label": {
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+ visit(terminal.block);
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+ break;
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+ }
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case "unsupported": {
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break;
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}
compiler/forget/src/HIR/PrintHIR.ts
+7
@@ -79,6 +79,7 @@ export function printMixedHIR(
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return printInstruction(value);
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}
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switch (value.kind) {
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+ case "label":
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case "optional-call":
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case "branch":
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case "if":
@@ -213,6 +214,12 @@ export function printTerminal(terminal: Terminal): Array<string> | string {
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value = `[${terminal.id}] ForOf init=bb${terminal.init} loop=bb${terminal.loop} fallthrough=bb${terminal.fallthrough}`;
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break;
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}
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+ case "label": {
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+ value = `[${terminal.id}] Label block=bb${terminal.block} fallthrough=${
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+ terminal.fallthrough ? `bb${terminal.fallthrough}` : ""
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+ }`;
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+ break;
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+ }
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case "unsupported": {
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value = `Unsupported`;
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break;
compiler/forget/src/HIR/visitors.ts
+18
@@ -659,6 +659,18 @@ export function mapTerminalSuccessors(
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id: makeInstructionId(0),
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};
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}
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+ case "label": {
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+ const block = fn(terminal.block);
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+ const fallthrough =
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+ terminal.fallthrough !== null ? fn(terminal.fallthrough) : null;
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+ return {
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+ kind: "label",
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+ block,
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+ fallthrough,
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+ id: makeInstructionId(0),
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+ loc: terminal.loc,
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+ };
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+ }
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case "unsupported": {
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return terminal;
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}
@@ -726,6 +738,10 @@ export function* eachTerminalSuccessor(terminal: Terminal): Iterable<BlockId> {
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yield terminal.init;
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break;
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}
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+ case "label": {
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+ yield terminal.block;
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+ break;
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+ }
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case "unsupported":
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break;
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default: {
@@ -767,6 +783,7 @@ export function mapTerminalOperands(
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}
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break;
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}
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+ case "label":
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case "optional-call":
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case "ternary":
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case "logical":
@@ -815,6 +832,7 @@ export function* eachTerminalOperand(terminal: Terminal): Iterable<Place> {
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}
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break;
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}
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+ case "label":
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case "optional-call":
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case "ternary":
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case "logical":
compiler/forget/src/ReactiveScopes/BuildReactiveFunction.ts
+4
@@ -29,6 +29,7 @@ import {
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ReactiveValue,
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Terminal,
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} from "../HIR/HIR";
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+import todo from "../Utils/todo";
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import { assertExhaustive } from "../Utils/utils";
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/**
@@ -529,6 +530,9 @@ class Driver {
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break;
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}
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+ case "label": {
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+ todo("Support label terminals");
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+ }
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case "optional-call":
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case "ternary":
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case "logical": {
compiler/forget/src/Utils/VisualizeHIRMermaid.ts
+13
@@ -131,6 +131,10 @@ function printTerminalLabel(terminal: Terminal): string {
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case "for-of":
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buffer.push("ForOf");
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break;
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+ case "label": {
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+ buffer.push("Label");
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+ break;
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+ }
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case "unsupported": {
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break;
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}
@@ -224,6 +228,15 @@ function printTerminalArrows(blockId: BlockId, terminal: Terminal): string {
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buffer.push(printJumpArrow(blockId, terminal.loop, "loop"));
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break;
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}
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+ case "label": {
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+ buffer.push(printJumpArrow(blockId, terminal.block, "block"));
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+ if (terminal.fallthrough != null) {
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+ buffer.push(
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+ printJumpArrow(blockId, terminal.fallthrough, "fallthrough")
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+ );
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+ }
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+ break;
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+ }
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case "throw":
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case "return":
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case "unsupported": {