Added for sanity checking (no intervening mallocs in test).

Author: emeryberger

src/malloc-counter.cpp

@@ -0,0 +1,54 @@
+// clang++ -compatibility_version 1 -current_version 1 -dynamiclib malloc-counter.cpp printf.cpp -o malloc-counter.dylib
+
+
+// -*- C++ -*-
+
+#ifndef HL_MACINTERPOSE_H
+#define HL_MACINTERPOSE_H
+
+// The interposition data structure (just pairs of function pointers),
+// used an interposition table like the following:
+//
+
+typedef struct interpose_s {
+  void *new_func;
+  void *orig_func;
+} interpose_t;
+
+#define MAC_INTERPOSE(newf,oldf) __attribute__((used)) \
+  static const interpose_t macinterpose##newf##oldf \
+  __attribute__ ((section("__DATA, __interpose"))) = \
+    { (void *) newf, (void *) oldf }
+
+#endif
+
+#include <stdlib.h>
+#include <malloc/malloc.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "printf.h"
+
+// For use by the replacement printf routines (see
+// https://github.com/mpaland/printf)
+extern "C" void _putchar(char ch) { ::write(1, (void *)&ch, 1); }
+
+static int mallocs = 0;
+static int frees = 0;
+
+extern "C" void * replace_malloc(size_t sz) {
+  auto ptr = ::malloc(sz);
+  ++mallocs;
+  printf_("malloc(%lu): %d\n", sz, mallocs);
+  return ptr;
+}
+
+extern "C" void replace_free(void * ptr) {
+  ++frees;
+  printf_("frees: %d\n", frees);
+  ::free(ptr);
+}
+
+MAC_INTERPOSE(replace_malloc, malloc);
+MAC_INTERPOSE(replace_free, free);
+