http://cs241.cs.illinois.edu/malloc.html

There is (or at least was) a score board you can compare against. By the end of the MP, there are usually handful beating libc.

The thing is.. libc is battle tested, so I'd always trust it over a hand rolled solution. It's always interesting to see improvements though (usually at a cost).

I'm confused; isn't libc an interface and not an implementation?

  // Really trivial malloc() implementation. We just allocate bytes sequentially from the start of
  // the heap, and reset the whole heap to empty at the start of each request.
  extern byte __heap_base;   // Start of heap -- symbol provided by compiler.

  byte* heap = NULL;         // Current heap position.
  void* last_malloc = NULL;  // Last value returned by malloc(), for trivial optimizations.

  void* malloc(size_t n) {
    last_malloc = heap;
    heap += n;
    return last_malloc;
  }

Shouldn't it be:

  byte *heap = &__heap_base;

I haven't read the rest of the code, nor know how WebAssembly works, but I can't make sense of that snippet.

    // init() is called from JS to allocate space for the image file.
    byte* init(size_t image_size) {
      // Reset the heap to empty. (See malloc() implementation in bootstrap.h.)
      heap = &__heap_base;

tldr; Appears very much an in-joke between work colleagues at Cloudflare :)

Also, is there a badge or sash I can get somewhere saying "Not a Real C Programmer"?