Add heap-profiling script

script/heap-profile

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+#
+# Usage:
+#   script/heap-profile
+#
+# Parse an example source file and record memory usage
+#
+# Dependencies:
+#   * `pprof` executable:   https://github.com/google/pprof
+#   * `gperftools` package: https://github.com/gperftools/gperftools
+
+set -e
+
+GRAMMARS_DIR=$PWD/test/fixtures/grammars
+
+# Build the library
+make
+
+# Build the heap-profiling harness
+clang++                               \
+  -I lib/include                      \
+  -I $GRAMMARS_DIR                    \
+  -D GRAMMARS_DIR=\"${GRAMMARS_DIR}/\" \
+  -l tcmalloc                         \
+  ./libtree-sitter.a                  \
+  test/profile/heap.cc                \
+  -o target/heap-profile
+
+# Run the harness with heap profiling enabled.
+export HEAPPROFILE=$PWD/profile
+target/heap-profile $@
+
+# Extract statistics using pprof.
+pprof -top -cum profile.0001.heap

test/profile/heap.cc

@@ -0,0 +1,42 @@
+#include <fstream>
+#include <string>
+#include <cstdlib>
+#include <tree_sitter/api.h>
+
+extern "C" {
+#include "javascript/src/parser.c"
+#include "javascript/src/scanner.c"
+}
+
+#define LANGUAGE tree_sitter_javascript
+#define SOURCE_PATH "javascript/examples/jquery.js"
+
+int main() {
+  TSParser *parser = ts_parser_new();
+  if (!ts_parser_set_language(parser, LANGUAGE())) {
+    fprintf(stderr, "Invalid language\n");
+    exit(1);
+  }
+
+  const char *source_path = GRAMMARS_DIR SOURCE_PATH;
+
+  printf("Parsing %s\n", source_path);
+
+  std::ifstream source_file(source_path);
+  if (!source_file.good()) {
+    fprintf(stderr, "Invalid source path %s\n", source_path);
+    exit(1);
+  }
+
+  std::string source_code(
+    (std::istreambuf_iterator<char>(source_file)),
+    std::istreambuf_iterator<char>()
+  );
+
+  TSTree *tree = ts_parser_parse_string(
+    parser,
+    NULL,
+    source_code.c_str(),
+    source_code.size()
+  );
+}