C Call Graph

Explore C function call relationships and global/macro references in a Source Insight-style relation graph — right inside VS Code.

Place the cursor on a C function and instantly see who calls it (right) and what it calls (left) in a single bidirectional tree that follows your cursor. No compiler, no compile_commands.json, no setup — parsing is built in via web-tree-sitter and the index is stored with sql.js (pure WebAssembly, so the same package runs on any platform and any VS Code version).

Features

• Relation Graph (bottom panel): bidirectional, cursor-following call tree.
  • Right = callers (who calls this function)
  • Left = callees (what this function calls)
  • Lazily expand to any depth (click ▸ / ◂)
  • Each node shows the call-site line; double-click to jump there
  • Drag to pan, scroll to zoom
• Variables mode: put the cursor on a global/static variable or #define macro → see which functions reference it.
• Force-directed graph: right-click → Show Call Graph for a global view.
• Automatic & incremental indexing of .c/.h files; only changed files are re-parsed on save.
• Resolves static functions, extern "C" blocks, function-pointer/callback registrations, and cross-file calls (by name — C has no overloading, so this is accurate in practice).

The index lives at .vscode/cbm.db inside your project.

Usage

1. Open a C project. It indexes automatically (progress in the status bar).
2. Open the C Relations panel (bottom, next to Terminal/Output).
3. Move the cursor onto a function or variable — the graph updates.
4. Click ▸/◂ to expand, double-click a node to jump to the call-site.

Toggle Follow to freeze the current root. Run C Call Graph: Reindex Project from the command palette to force a full rebuild.

Requirements

None. Works out of the box on any C codebase.

Known limitations

• C only.
• Cross-file resolution is name-based (function-pointer indirection through variables and macro-expanded calls are not tracked).
• Header files must be associated with the c language for the context menu.

Development

npm install
npm run compile
node scripts/test-parser.js
npx tsc --outDir out && node scripts/test-store.js
npx vsce package

Press F5 to launch an Extension Development Host.

License

Apache-2.0 © Flianfa