fbt: support for LOADER_AUTOSTART; post-build size stats (#1594)

* fbt: restored LOADER_AUTOSTART support
* scripts: added fwsize.py wrapper for size command; fbt: changed size post-build stats to fwsize.py call
* fbt: removed size wrapper
* fbt: added stats for binary flash size in pages
* fbt: hint on build options details
* scripts: fixed fwsize.py for *nix

scripts/fwsize.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+
+from flipper.app import App
+import subprocess
+import os
+import math
+
+
+class Main(App):
+    def init(self):
+        self.subparsers = self.parser.add_subparsers(help="sub-command help")
+
+        self.parser_elfsize = self.subparsers.add_parser("elf", help="Dump elf stats")
+        self.parser_elfsize.add_argument("elfname", action="store")
+        self.parser_elfsize.set_defaults(func=self.process_elf)
+
+        self.parser_binsize = self.subparsers.add_parser("bin", help="Dump bin stats")
+        self.parser_binsize.add_argument("binname", action="store")
+        self.parser_binsize.set_defaults(func=self.process_bin)
+
+    def process_elf(self):
+        all_sizes = subprocess.check_output(
+            ["arm-none-eabi-size", "-A", self.args.elfname], shell=False
+        )
+        all_sizes = all_sizes.splitlines()
+
+        sections_to_keep = (".text", ".rodata", ".data", ".bss", ".free_flash")
+        for line in all_sizes:
+            line = line.decode("utf-8")
+            parts = line.split()
+            if len(parts) != 3:
+                continue
+            section, size, _ = parts
+            if section not in sections_to_keep:
+                continue
+            print(f"{section:<11} {size:>8} ({(int(size)/1024):6.2f} K)")
+
+        return 0
+
+    def process_bin(self):
+        PAGE_SIZE = 4096
+        binsize = os.path.getsize(self.args.binname)
+        pages = math.ceil(binsize / PAGE_SIZE)
+        last_page_state = (binsize % PAGE_SIZE) * 100 / PAGE_SIZE
+        print(
+            f"{os.path.basename(self.args.binname):<11}: {pages:>4} flash pages (last page {last_page_state:.02f}% full)"
+        )
+        return 0
+
+
+if __name__ == "__main__":
+    Main()()