perf(cfnptr): skip generated C; detect bannerless tree-sitter parsers

CHANGELOG.md

@@ -398,6 +398,8 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 - The Claude Code prompt hook no longer runs on the task-notification messages Claude Code injects when a background agent finishes, removing a multi-second stall on every such turn. (#1832)
 
+- Indexing a project that vendors tree-sitter grammars is faster: the C function-pointer pass now skips generated C files, and a tree-sitter `parser.c` counts as generated even when it carries no banner (releases before 0.25 print none).
+
 - Rust calls on `self` now stay with the enclosing type instead of linking to an unrelated type’s same-named method. Thanks @L4XB. (#1861)
 
 - Turning telemetry off now resets its identity and stops running processes from recording, sending, or restoring unsent data. (#1869)

__tests__/generated-detection.test.ts

@@ -187,6 +187,13 @@ describe('hasGeneratedHeader — per-marker coverage (#1500)', () => {
     expect(hasGeneratedHeader(`${shortFiller}\n// Code generated by foo. DO NOT EDIT.\npackage main\n`)).toBe(true);
   });
 
+  it('flags a bannerless tree-sitter parser.c, not the grammar\'s hand-written scanner.c', () => {
+    const parser = '#include "tree_sitter/parser.h"\n\n#if defined(__GNUC__)\n#pragma GCC diagnostic ignored "-Wmissing-field-initializers"\n#endif\n\n#define LANGUAGE_VERSION 14\n#define STATE_COUNT 9\n';
+    const scanner = '#include "tree_sitter/parser.h"\n#include <wctype.h>\n\nenum TokenType { AUTOMATIC_SEMICOLON };\n';
+    expect(hasGeneratedHeader(parser)).toBe(true);
+    expect(hasGeneratedHeader(scanner)).toBe(false);
+  });
+
   it('requires a comment line — the same words in executable code are not a banner', () => {
     // No comment leader, no open block: this is a bare statement.
     expect(hasGeneratedHeader('const banner = "Code generated by tool. DO NOT EDIT.";\n')).toBe(false);

src/extraction/generated-detection.ts

@@ -195,6 +195,16 @@ const GENERATED_CONTENT_PATTERNS: ReadonlyArray<RegExp> = [
   /\bdo not (?:edit|modify)\b.{0,120}?\b(?:auto[- ]?generated|generated file|generated code)\b/i,
 ];
 
+/**
+ * A tree-sitter `parser.c`. Releases before 0.25 print no banner, but every
+ * generated parser includes the runtime header and defines
+ * `LANGUAGE_VERSION`; a grammar's hand-written `scanner.c` includes the
+ * header and never defines the version.
+ */
+function isTreeSitterParser(head: string): boolean {
+  return /^#include\s+"tree_sitter\/parser\.h"/m.test(head) && /^#define\s+LANGUAGE_VERSION\s+\d+/m.test(head);
+}
+
 /**
  * Whether the head of `content` carries a recognized machine-generation
  * banner. Bounded to {@link HEADER_SCAN_CHARS} / {@link HEADER_SCAN_LINES},
@@ -208,6 +218,7 @@ export function hasGeneratedHeader(content: string): boolean {
   if (!content) return false;
 
   const head = content.length > HEADER_SCAN_CHARS ? content.slice(0, HEADER_SCAN_CHARS) : content;
+  if (isTreeSitterParser(head)) return true;
   // Fast reject for ~every hand-written file: no line splitting, no allocation
   // (V8 keeps `head` as a sliced view of `content`).
   if (!GENERATED_STEM.test(head)) return false;

src/resolution/c-fnptr-synthesizer.ts

@@ -432,13 +432,19 @@ interface FileFacts {
 const NO_INCLUDES: string[] = [];
 
 export async function cFnPointerDispatchEdges(
-  _queries: QueryBuilder,
+  queries: QueryBuilder,
   ctx: ResolutionContext,
   onYield: MaybeYield,
   onFraction?: (fraction: number) => void
 ): Promise<Edge[]> {
   let scannedFiles = 0;
-  const files = ctx.getAllFiles().filter((f) => C_CPP_EXT.test(f));
+  const cFiles = ctx.getAllFiles().filter((f) => C_CPP_EXT.test(f));
+  // Generated C (parser tables, protobuf-c, bison output) holds data tables,
+  // not the hand-written registrations and dispatch sites this pass links,
+  // and it can dwarf the real code: 248 MB of tree-sitter parsers in one
+  // repository, for no edges.
+  const generated = queries.generatedPredicateFor(cFiles);
+  const files = cFiles.filter((f) => !generated(f));
   if (files.length === 0) return [];
 
   // CODEGRAPH_SYNTH_TIMINGS sub-attribution: this pass is 86% of kernel-scale