diff --git a/Makefile b/Makefile
index 0f67a53..1623569 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,7 @@ SRC ?= $(wildcard *.c)
 OBJ := $(SRC:%.c=$(BUILDDIR)%.o)
 DEP := $(SRC:%.c=$(BUILDDIR)%.d)
 ASM := $(SRC:%.c=$(BUILDDIR)%.s)
+CGI := $(SRC:%.c=$(BUILDDIR)%.ci)
 
 ifdef DEBUG
 override CFLAGS += -O0 -g3
@@ -54,6 +55,7 @@ ifdef BUILDDIR
 override TESTFLAGS += --build-dir="$(BUILDDIR:/=)"
 override CODEFLAGS += --build-dir="$(BUILDDIR:/=)"
 override DATAFLAGS += --build-dir="$(BUILDDIR:/=)"
+override CALLSFLAGS += --build-dir="$(BUILDDIR:/=)"
 endif
 ifneq ($(NM),nm)
 override CODEFLAGS += --nm-tool="$(NM)"
@@ -84,6 +86,10 @@ code: $(OBJ)
 data: $(OBJ)
 	./scripts/data.py -S $^ $(DATAFLAGS)
 
+.PHONY: calls
+calls: $(CGI)
+	./scripts/calls.py $^ $(CALLSFLAGS)
+
 .PHONY: test
 test:
 	./scripts/test.py $(TESTFLAGS)
@@ -111,11 +117,15 @@ $(BUILDDIR)%.o: %.c
 $(BUILDDIR)%.s: %.c
 	$(CC) -S $(CFLAGS) $< -o $@
 
+$(BUILDDIR)%.ci: %.c
+	$(CC) -c -MMD -fcallgraph-info=su $(CFLAGS) $< -o $(@:.ci=.o)
+
 # clean everything
 .PHONY: clean
 clean:
 	rm -f $(TARGET)
 	rm -f $(OBJ)
+	rm -f $(CGI)
 	rm -f $(DEP)
 	rm -f $(ASM)
 	rm -f $(BUILDDIR)tests/*.toml.*
diff --git a/scripts/calls.py b/scripts/calls.py
new file mode 100755
index 0000000..61cce8f
--- /dev/null
+++ b/scripts/calls.py
@@ -0,0 +1,170 @@
+#!/usr/bin/env python3
+#
+# Script to show the callgraph in a human readable manner. Basically just a
+# wrapper aroung GCC's -fcallgraph-info flag.
+#
+
+import os
+import glob
+import itertools as it
+import re
+import csv
+import collections as co
+
+
+CI_PATHS = ['*.ci']
+
+def collect(paths, **args):
+    # parse the vcg format
+    k_pattern = re.compile('([a-z]+)\s*:', re.DOTALL)
+    v_pattern = re.compile('(?:"(.*?)"|([a-z]+))', re.DOTALL)
+    def parse_vcg(rest):
+        def parse_vcg(rest):
+            node = []
+            while True:
+                rest = rest.lstrip()
+                m = k_pattern.match(rest)
+                if not m:
+                    return (node, rest)
+                k, rest = m.group(1), rest[m.end(0):]
+
+                rest = rest.lstrip()
+                if rest.startswith('{'):
+                    v, rest = parse_vcg(rest[1:])
+                    assert rest[0] == '}', "unexpected %r" % rest[0:1]
+                    rest = rest[1:]
+                    node.append((k, v))
+                else:
+                    m = v_pattern.match(rest)
+                    assert m, "unexpected %r" % rest[0:1]
+                    v, rest = m.group(1) or m.group(2), rest[m.end(0):]
+                    node.append((k, v))
+
+        node, rest = parse_vcg(rest)
+        assert rest == '', "unexpected %r" % rest[0:1]
+        return node
+
+    # collect into functions
+    results = co.defaultdict(lambda: (None, None, set()))
+    f_pattern = re.compile(r'([^\\]*)\\n([^:]*)')
+    for path in paths:
+        with open(path) as f:
+            vcg = parse_vcg(f.read())
+        for k, graph in vcg:
+            if k != 'graph':
+                continue
+            for k, info in graph:
+                if k == 'node':
+                    info = dict(info)
+                    m = f_pattern.match(info['label'])
+                    if m:
+                        function, file = m.groups()
+                        _, _, targets = results[info['title']]
+                        results[info['title']] = (file, function, targets)
+                elif k == 'edge':
+                    info = dict(info)
+                    _, _, targets = results[info['sourcename']]
+                    targets.add(info['targetname'])
+                else:
+                    continue
+
+    if not args.get('everything'):
+        for source, (s_file, s_function, _) in list(results.items()):
+            # discard internal functions
+            if s_file.startswith('<') or s_file.startswith('/usr/include'):
+                del results[source]
+
+    # flatten into a list
+    flat_results = []
+    for _, (s_file, s_function, targets) in results.items():
+        for target in targets:
+            if target not in results:
+                continue
+
+            t_file, t_function, _ = results[target]
+            flat_results.append((s_file, s_function, t_file, t_function))
+
+    return flat_results
+
+def main(**args):
+    # find sizes
+    if not args.get('use', None):
+        # find .ci files
+        paths = []
+        for path in args['ci_paths']:
+            if os.path.isdir(path):
+                path = path + '/*.ci'
+
+            for path in glob.glob(path):
+                paths.append(path)
+
+        if not paths:
+            print('no .ci files found in %r?' % args['ci_paths'])
+            sys.exit(-1)
+
+        results = collect(paths, **args)
+    else:
+        with open(args['use']) as f:
+            r = csv.DictReader(f)
+            results = [
+                (   result['file'],
+                    result['function'],
+                    result['callee_file'],
+                    result['callee_function'])
+                for result in r]
+
+    # write results to CSV
+    if args.get('output'):
+        with open(args['output'], 'w') as f:
+            w = csv.writer(f)
+            w.writerow(['file', 'function', 'callee_file', 'callee_function'])
+            for file, func, c_file, c_func in sorted(results):
+                w.writerow((file, func, c_file, c_func))
+
+    # print results
+    def dedup_entries(results, by='function'):
+        entries = co.defaultdict(lambda: set())
+        for file, func, c_file, c_func in results:
+            entry = (file if by == 'file' else func)
+            entries[entry].add(c_file if by == 'file' else c_func)
+        return entries
+
+    def print_entries(by='function'):
+        entries = dedup_entries(results, by=by)
+
+        for name, callees in sorted(entries.items()):
+            print(name)
+            for i, c_name in enumerate(sorted(callees)):
+                print(" -> %s" % c_name)
+
+    if args.get('quiet'):
+        pass
+    elif args.get('files'):
+        print_entries(by='file')
+    else:
+        print_entries(by='function')
+
+if __name__ == "__main__":
+    import argparse
+    import sys
+    parser = argparse.ArgumentParser(
+        description="Find code size at the function level.")
+    parser.add_argument('ci_paths', nargs='*', default=CI_PATHS,
+        help="Description of where to find *.ci files. May be a directory \
+            or a list of paths. Defaults to %r." % CI_PATHS)
+    parser.add_argument('-v', '--verbose', action='store_true',
+        help="Output commands that run behind the scenes.")
+    parser.add_argument('-o', '--output',
+        help="Specify CSV file to store results.")
+    parser.add_argument('-u', '--use',
+        help="Don't parse callgraph files, instead use this CSV file.")
+    parser.add_argument('-A', '--everything', action='store_true',
+        help="Include builtin and libc specific symbols.")
+    parser.add_argument('--files', action='store_true',
+        help="Show file-level calls.")
+    parser.add_argument('-q', '--quiet', action='store_true',
+        help="Don't show anything, useful with -o.")
+    parser.add_argument('--build-dir',
+        help="Specify the relative build directory. Used to map object files \
+            to the correct source files.")
+    sys.exit(main(**vars(parser.parse_args())))
diff --git a/scripts/code.py b/scripts/code.py
index 75508a5..e257d86 100755
--- a/scripts/code.py
+++ b/scripts/code.py
@@ -49,8 +49,9 @@ def collect(paths, **args):
         if args.get('build_dir'):
             file = re.sub('%s/*' % re.escape(args['build_dir']), '', file)
         # discard internal functions
-        if func.startswith('__'):
-            continue
+        if not args.get('everything'):
+            if func.startswith('__'):
+                continue
         # discard .8449 suffixes created by optimizer
         func = re.sub('\.[0-9]+', '', func)
         flat_results.append((file, func, size))
@@ -128,19 +129,19 @@ def main(**args):
 
     def sorted_entries(entries):
         if args.get('size_sort'):
-            return sorted(entries.items(), key=lambda x: (-x[1], x))
+            return sorted(entries, key=lambda x: (-x[1], x))
         elif args.get('reverse_size_sort'):
-            return sorted(entries.items(), key=lambda x: (+x[1], x))
+            return sorted(entries, key=lambda x: (+x[1], x))
         else:
-            return sorted(entries.items())
+            return sorted(entries)
 
     def sorted_diff_entries(entries):
         if args.get('size_sort'):
-            return sorted(entries.items(), key=lambda x: (-x[1][1], x))
+            return sorted(entries, key=lambda x: (-x[1][1], x))
         elif args.get('reverse_size_sort'):
-            return sorted(entries.items(), key=lambda x: (+x[1][1], x))
+            return sorted(entries, key=lambda x: (+x[1][1], x))
         else:
-            return sorted(entries.items(), key=lambda x: (-x[1][3], x))
+            return sorted(entries, key=lambda x: (-x[1][3], x))
 
     def print_header(by=''):
         if not args.get('diff'):
@@ -153,7 +154,7 @@ def main(**args):
 
         if not args.get('diff'):
             print_header(by=by)
-            for name, size in sorted_entries(entries):
+            for name, size in sorted_entries(entries.items()):
                 print("%-36s %7d" % (name, size))
         else:
             prev_entries = dedup_entries(prev_results, by=by)
@@ -161,7 +162,7 @@ def main(**args):
             print_header(by='%s (%d added, %d removed)' % (by,
                 sum(1 for old, _, _, _ in diff.values() if not old),
                 sum(1 for _, new, _, _ in diff.values() if not new)))
-            for name, (old, new, diff, ratio) in sorted_diff_entries(diff):
+            for name, (old, new, diff, ratio) in sorted_diff_entries(diff.items()):
                 if ratio or args.get('all'):
                     print("%-36s %7s %7s %+7d%s" % (name,
                         old or "-",
@@ -211,6 +212,8 @@ if __name__ == "__main__":
         help="Specify CSV file to diff code size against.")
     parser.add_argument('-a', '--all', action='store_true',
         help="Show all functions, not just the ones that changed.")
+    parser.add_argument('-A', '--everything', action='store_true',
+        help="Include builtin and libc specific symbols.")
     parser.add_argument('-s', '--size-sort', action='store_true',
         help="Sort by size.")
     parser.add_argument('-S', '--reverse-size-sort', action='store_true',
diff --git a/scripts/coverage.py b/scripts/coverage.py
index 7abdedb..7f21ef0 100755
--- a/scripts/coverage.py
+++ b/scripts/coverage.py
@@ -55,8 +55,9 @@ def collect(paths, **args):
     for (file, func), (hits, count) in reduced_funcs.items():
         # discard internal/testing functions (test_* injected with
         # internal testing)
-        if func.startswith('__') or func.startswith('test_'):
-            continue
+        if not args.get('everything'):
+            if func.startswith('__') or func.startswith('test_'):
+                continue
         # discard .8449 suffixes created by optimizer
         func = re.sub('\.[0-9]+', '', func)
         results.append((file, func, hits, count))
@@ -245,6 +246,8 @@ if __name__ == "__main__":
         help="Specify CSV file to diff code size against.")
     parser.add_argument('-a', '--all', action='store_true',
         help="Show all functions, not just the ones that changed.")
+    parser.add_argument('-A', '--everything', action='store_true',
+        help="Include builtin and libc specific symbols.")
     parser.add_argument('--files', action='store_true',
         help="Show file-level coverage.")
     parser.add_argument('--summary', action='store_true',
diff --git a/scripts/data.py b/scripts/data.py
index ce21f69..25ee44f 100755
--- a/scripts/data.py
+++ b/scripts/data.py
@@ -49,8 +49,9 @@ def collect(paths, **args):
         if args.get('build_dir'):
             file = re.sub('%s/*' % re.escape(args['build_dir']), '', file)
         # discard internal functions
-        if func.startswith('__'):
-            continue
+        if not args.get('everything'):
+            if func.startswith('__'):
+                continue
         # discard .8449 suffixes created by optimizer
         func = re.sub('\.[0-9]+', '', func)
         flat_results.append((file, func, size))
@@ -128,19 +129,19 @@ def main(**args):
 
     def sorted_entries(entries):
         if args.get('size_sort'):
-            return sorted(entries.items(), key=lambda x: (-x[1], x))
+            return sorted(entries, key=lambda x: (-x[1], x))
         elif args.get('reverse_size_sort'):
-            return sorted(entries.items(), key=lambda x: (+x[1], x))
+            return sorted(entries, key=lambda x: (+x[1], x))
         else:
-            return sorted(entries.items())
+            return sorted(entries)
 
     def sorted_diff_entries(entries):
         if args.get('size_sort'):
-            return sorted(entries.items(), key=lambda x: (-x[1][1], x))
+            return sorted(entries, key=lambda x: (-x[1][1], x))
         elif args.get('reverse_size_sort'):
-            return sorted(entries.items(), key=lambda x: (+x[1][1], x))
+            return sorted(entries, key=lambda x: (+x[1][1], x))
         else:
-            return sorted(entries.items(), key=lambda x: (-x[1][3], x))
+            return sorted(entries, key=lambda x: (-x[1][3], x))
 
     def print_header(by=''):
         if not args.get('diff'):
@@ -153,7 +154,7 @@ def main(**args):
 
         if not args.get('diff'):
             print_header(by=by)
-            for name, size in sorted_entries(entries):
+            for name, size in sorted_entries(entries.items()):
                 print("%-36s %7d" % (name, size))
         else:
             prev_entries = dedup_entries(prev_results, by=by)
@@ -161,7 +162,7 @@ def main(**args):
             print_header(by='%s (%d added, %d removed)' % (by,
                 sum(1 for old, _, _, _ in diff.values() if not old),
                 sum(1 for _, new, _, _ in diff.values() if not new)))
-            for name, (old, new, diff, ratio) in sorted_diff_entries(diff):
+            for name, (old, new, diff, ratio) in sorted_diff_entries(diff.items()):
                 if ratio or args.get('all'):
                     print("%-36s %7s %7s %+7d%s" % (name,
                         old or "-",
@@ -211,6 +212,8 @@ if __name__ == "__main__":
         help="Specify CSV file to diff data size against.")
     parser.add_argument('-a', '--all', action='store_true',
         help="Show all functions, not just the ones that changed.")
+    parser.add_argument('-A', '--everything', action='store_true',
+        help="Include builtin and libc specific symbols.")
     parser.add_argument('-s', '--size-sort', action='store_true',
         help="Sort by size.")
     parser.add_argument('-S', '--reverse-size-sort', action='store_true',