Added scripts/code_size.py, for more in-depth code-size reporting

Inspired by Linux's Bloat-O-Meter, code_size.py wraps nm to provide
function-level code size, and supports detailed comparison between
different builds.

One difference is that code_size.py invokes littlefs's build system
similarly to test.py, creating a duplicate build in the "sizes"
directory. This makes it easy to monitor a cross-compiled build size
while simultaneously testing on the host machine.

Makefile

@@ -6,6 +6,7 @@ endif
 CC ?= gcc
 AR ?= ar
 SIZE ?= size
+NM ?= nm
 
 SRC += $(wildcard *.c bd/*.c)
 OBJ := $(SRC:.c=.o)
@@ -29,6 +30,7 @@ override CFLAGS += -Wextra -Wshadow -Wjump-misses-init -Wundef
 
 ifdef VERBOSE
 override TFLAGS += -v
+override SFLAGS += -v
 endif
 
 
@@ -39,6 +41,9 @@ asm: $(ASM)
 size: $(OBJ)
 	$(SIZE) -t $^
 
+code_size:
+	./scripts/code_size.py $(SFLAGS)
+
 test:
 	./scripts/test.py $(TFLAGS)
 .SECONDEXPANSION:
@@ -65,3 +70,4 @@ clean:
 	rm -f $(DEP)
 	rm -f $(ASM)
 	rm -f tests/*.toml.*
+	rm -f sizes/*

scripts/code_size.py

@@ -0,0 +1,328 @@
+#!/usr/bin/env python3
+#
+# This script finds the code size at the function level, with/without
+# static functions, and has some conveniences for comparing different
+# versions. It's basically one big wrapper around nm, and may or may
+# not have been written out of jealousy of Linux's Bloat-O-Meter.
+#
+# Here's a useful bash script to use while developing:
+# ./scripts/code_size.py -qo old.csv
+# while true ; do ./code_scripts/size.py -d old.csv ; inotifywait -rqe modify * ; done
+#
+# Or even better, to automatically update results on commit:
+# ./scripts/code_size.py -qo commit.csv
+# while true ; do ./scripts/code_size.py -d commit.csv -o current.csv ; git diff --exit-code --quiet && cp current.csv commit.csv ; inotifywait -rqe modify * ; done
+#
+# Or my personal favorite:
+# ./scripts/code_size.py -qo master.csv && cp master.csv commit.csv
+# while true ; do ( ./scripts/code_size.py -i commit.csv -d master.csv -s ; ./scripts/code_size.py -i current.csv -d master.csv -s ; ./scripts/code_size.py -d master.csv -o current.csv -s ) | awk 'BEGIN {printf "%-16s %7s %7s %7s\n","","old","new","diff"} (NR==2 && $1="commit") || (NR==4 && $1="prev") || (NR==6 && $1="current") {printf "%-16s %7s %7s %7s %s\n",$1,$2,$3,$5,$6}' ; git diff --exit-code --quiet && cp current.csv commit.csv ; inotifywait -rqe modify * ; done
+#
+
+import os
+import itertools as it
+import subprocess as sp
+import shlex
+import re
+import csv
+import collections as co
+
+SIZEDIR = 'sizes'
+RULES = """
+define FLATTEN
+%(sizedir)s/%(build)s.$(subst /,.,$(target)): $(target)
+    ( echo "#line 1 \\"$$<\\"" ; %(cat)s $$< ) > $$@
+%(sizedir)s/%(build)s.$(subst /,.,$(target:.c=.size)): \\
+        %(sizedir)s/%(build)s.$(subst /,.,$(target:.c=.o))
+    $(NM) --size-sort $$^ | sed 's/^/$(subst /,\\/,$(target:.c=.o)):/' > $$@
+endef
+$(foreach target,$(SRC),$(eval $(FLATTEN)))
+
+-include %(sizedir)s/*.d
+.SECONDARY:
+
+%%.size: $(foreach t,$(subst /,.,$(SRC:.c=.size)),%%.$t)
+    cat $^ > $@
+"""
+CATS = {
+    'code': 'cat',
+    'code_inlined': 'sed \'s/^static\( inline\)\?//\'',
+}
+
+def build(**args):
+    # mkdir -p sizedir
+    os.makedirs(args['sizedir'], exist_ok=True)
+
+    if args.get('inlined', False):
+        builds = ['code', 'code_inlined']
+    else:
+        builds = ['code']
+
+    # write makefiles for the different types of builds
+    makefiles = []
+    targets = []
+    for build in builds:
+        path = args['sizedir'] + '/' + build
+        with open(path + '.mk', 'w') as mk:
+            mk.write(RULES.replace(4*' ', '\t') % dict(
+                sizedir=args['sizedir'],
+                build=build,
+                cat=CATS[build]))
+            mk.write('\n')
+
+            # pass on defines
+            for d in args['D']:
+                mk.write('%s: override CFLAGS += -D%s\n' % (
+                    path+'.size', d))
+
+        makefiles.append(path + '.mk')
+        targets.append(path + '.size')
+
+    # build in parallel
+    cmd = (['make', '-f', 'Makefile'] +
+        list(it.chain.from_iterable(['-f', m] for m in makefiles)) +
+        [target for target in targets])
+    if args.get('verbose', False):
+        print(' '.join(shlex.quote(c) for c in cmd))
+    proc = sp.Popen(cmd,
+        stdout=sp.DEVNULL if not args.get('verbose', False) else None)
+    proc.wait()
+    if proc.returncode != 0:
+        sys.exit(-1)
+
+    # find results
+    build_results = co.defaultdict(lambda: 0)
+    # notes
+    # - filters type
+    # - discards internal/debug functions (leading __)
+    pattern = re.compile(
+        '^(?P<file>[^:]+)' +
+        ':(?P<size>[0-9a-fA-F]+)' +
+        ' (?P<type>[%s])' % re.escape(args['type']) +
+        ' (?!__)(?P<name>.+?)$')
+    for build in builds:
+        path = args['sizedir'] + '/' + build
+        with open(path + '.size') as size:
+            for line in size:
+                match = pattern.match(line)
+                if match:
+                    file = match.group('file')
+                    # discard .8449 suffixes created by optimizer
+                    name = re.sub('\.[0-9]+', '', match.group('name'))
+                    size = int(match.group('size'), 16)
+                    build_results[(build, file, name)] += size
+
+    results = []
+    for (build, file, name), size in build_results.items():
+        if build == 'code':
+            results.append((file, name, size, False))
+        elif (build == 'code_inlined' and
+                ('inlined', file, name) not in results):
+            results.append((file, name, size, True))
+
+    return results
+
+def main(**args):
+    # find results
+    if not args.get('input', None):
+        results = build(**args)
+    else:
+        with open(args['input']) as f:
+            r = csv.DictReader(f)
+            results = [
+                (   result['file'],
+                    result['name'],
+                    int(result['size']),
+                    bool(int(result.get('inlined', 0))))
+                for result in r
+                if (not bool(int(result.get('inlined', 0))) or
+                    args.get('inlined', False))]
+
+    total = 0
+    for _, _, size, inlined in results:
+        if not inlined:
+            total += size
+
+    # find previous results?
+    if args.get('diff', None):
+        with open(args['diff']) as f:
+            r = csv.DictReader(f)
+            prev_results = [
+                (   result['file'],
+                    result['name'],
+                    int(result['size']),
+                    bool(int(result.get('inlined', 0))))
+                for result in r
+                if (not bool(int(result.get('inlined', 0))) or
+                    args.get('inlined', False))]
+
+        prev_total = 0
+        for _, _, size, inlined in prev_results:
+            if not inlined:
+                prev_total += size
+
+    # write results to CSV
+    if args.get('output', None):
+        results.sort(key=lambda x: (-x[2], x))
+        with open(args['output'], 'w') as f:
+            w = csv.writer(f)
+            if args.get('inlined', False):
+                w.writerow(['file', 'name', 'size', 'inlined'])
+                for file, name, size, inlined in results:
+                    w.writerow((file, name, size, int(inlined)))
+            else:
+                w.writerow(['file', 'name', 'size'])
+                for file, name, size, inlined in results:
+                    w.writerow((file, name, size))
+
+    # print results
+    def dedup_functions(results):
+        functions = co.defaultdict(lambda: (0, True))
+        for _, name, size, inlined in results:
+            if not inlined:
+                functions[name] = (functions[name][0] + size, False)
+        for _, name, size, inlined in results:
+            if inlined and functions[name][1]:
+                functions[name] = (functions[name][0] + size, True)
+        return functions
+
+    def dedup_files(results):
+        files = co.defaultdict(lambda: 0)
+        for file, _, size, inlined in results:
+            if not inlined:
+                files[file] += size
+        return files
+
+    def diff_sizes(olds, news):
+        diff = co.defaultdict(lambda: (None, None, None))
+        for name, new in news.items():
+            diff[name] = (None, new, new)
+        for name, old in olds.items():
+            new = diff[name][1] or 0
+            diff[name] = (old, new, new-old)
+        return diff
+
+    def print_header(name=''):
+        if not args.get('diff', False):
+            print('%-40s %7s' % (name, 'size'))
+        else:
+            print('%-40s %7s %7s %7s' % (name, 'old', 'new', 'diff'))
+
+    def print_functions():
+        functions = dedup_functions(results)
+        functions = {
+            name+' (inlined)' if inlined else name: size
+            for name, (size, inlined) in functions.items()}
+
+        if not args.get('diff', None):
+            print_header('function')
+            for name, size in sorted(functions.items(),
+                    key=lambda x: (-x[1], x)):
+                print("%-40s %7d" % (name, size))
+        else:
+            prev_functions = dedup_functions(prev_results)
+            prev_functions = {
+                name+' (inlined)' if inlined else name: size
+                for name, (size, inlined) in prev_functions.items()}
+            diff = diff_sizes(functions, prev_functions)
+            print_header('function (%d added, %d removed)' % (
+                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) in sorted(diff.items(),
+                    key=lambda x: (-(x[1][2] or 0), x)):
+                if diff or args.get('all', False):
+                    print("%-40s %7s %7s %+7d%s" % (
+                        name, old or "-", new or "-", diff,
+                        ' (%+.2f%%)' % (100*((new-old)/old))
+                        if old and new else
+                        ''))
+
+    def print_files():
+        files = dedup_files(results)
+
+        if not args.get('diff', None):
+            print_header('file')
+            for file, size in sorted(files.items(),
+                    key=lambda x: (-x[1], x)):
+                print("%-40s %7d" % (file, size))
+        else:
+            prev_files = dedup_files(prev_results)
+            diff = diff_sizes(files, prev_files)
+            print_header('file (%d added, %d removed)' % (
+                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) in sorted(diff.items(),
+                    key=lambda x: (-(x[1][2] or 0), x)):
+                if diff or args.get('all', False):
+                    print("%-40s %7s %7s %+7d%s" % (
+                        name, old or "-", new or "-", diff,
+                        ' (%+.2f%%)' % (100*((new-old)/old))
+                        if old and new else
+                        ''))
+
+    def print_totals():
+        if not args.get('diff', None):
+            print("%-40s %7d" % ('TOTALS', total))
+        else:
+            print("%-40s %7s %7s %+7d%s" % (
+                'TOTALS', prev_total, total, total-prev_total,
+                ' (%+.2f%%)' % (100*((total-prev_total)/total))
+                if prev_total and total else
+                ''))
+
+    def print_status():
+        if not args.get('diff', None):
+            print(total)
+        else:
+            print("%d (%+.2f%%)" % (total, 100*((total-prev_total)/total)))
+
+    if args.get('quiet', False):
+        pass
+    elif args.get('status', False):
+        print_status()
+    elif args.get('summary', False):
+        print_header()
+        print_totals()
+    elif args.get('files', False):
+        print_files()
+        print_totals()
+    else:
+        print_functions()
+        print_totals()
+
+if __name__ == "__main__":
+    import argparse
+    import sys
+    parser = argparse.ArgumentParser(
+        description="Find code size at the function level.")
+    parser.add_argument('sizedir', nargs='?', default=SIZEDIR,
+        help="Directory to store intermediary results. Defaults "
+            "to \"%s\"." % SIZEDIR)
+    parser.add_argument('-D', action='append', default=[],
+        help="Specify compile-time define.")
+    parser.add_argument('-v', '--verbose', action='store_true',
+        help="Output commands that run behind the scenes.")
+    parser.add_argument('-i', '--input',
+        help="Don't compile and find code sizes, instead use this CSV file.")
+    parser.add_argument('-o', '--output',
+        help="Specify CSV file to store results.")
+    parser.add_argument('-d', '--diff',
+        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('--inlined', action='store_true',
+        help="Run a second compilation to find the sizes of functions normally "
+            "removed by optimizations. These will be shown as \"*.inlined\" "
+            "functions, and will not be included in the total.")
+    parser.add_argument('--files', action='store_true',
+        help="Show file-level code sizes. Note this does not include padding! "
+            "So sizes may differ from other tools.")
+    parser.add_argument('-s', '--summary', action='store_true',
+        help="Only show the total code size.")
+    parser.add_argument('-S', '--status', action='store_true',
+        help="Show minimum info useful for a single-line status.")
+    parser.add_argument('-q', '--quiet', action='store_true',
+        help="Don't show anything, useful with -o.")
+    parser.add_argument('--type', default='tTrRdDbB',
+        help="Type of symbols to report, this uses the same single-character "
+            "type-names emitted by nm. Defaults to %(default)r.")
+    sys.exit(main(**vars(parser.parse_args())))