getdeps: GH actions: strip artifacts before capturing them (#809)

Summary:
On Linux the debug info sections in projects downstream from folly and
thrift are huge due to a lot of C++ template usage.

We build in RelWithDebInfo mode as that is most useful when debugging
locally and because the build times are long, but most casual consumers
of the binaries via GH actions really don't care about debug info,
and this should save ~180MB of size in (for example) the watchman
executables.

Pull Request resolved: https://github.com/facebook/watchman/pull/809
Refs: https://github.com/facebook/watchman/issues/804

Test Plan:
Review the artifact size on the linux build in this PR (see
https://github.com/facebook/watchman/actions/runs/91688952) and confirm that it
is a bit smaller than 180MB; now under 3 MB.

Reviewed By: simpkins

Differential Revision: D21318302

Pulled By: wez

fbshipit-source-id: f78bc5e735dd78771e0604abae64c0a23cf9158d

.github/workflows/getdeps_linux.yml

@@ -64,7 +64,7 @@ jobs:
     - name: Build folly
       run: python3 build/fbcode_builder/getdeps.py --allow-system-packages build --src-dir=. folly  --project-install-prefix folly:/usr/local
     - name: Copy artifacts
-      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages fixup-dyn-deps --src-dir=. folly _artifacts/linux  --project-install-prefix folly:/usr/local --final-install-prefix /usr/local
+      run: python3 build/fbcode_builder/getdeps.py --allow-system-packages fixup-dyn-deps --strip --src-dir=. folly _artifacts/linux  --project-install-prefix folly:/usr/local --final-install-prefix /usr/local
     - uses: actions/upload-artifact@master
       with:
         name: folly

build/fbcode_builder/getdeps.py

@@ -572,7 +572,9 @@ class FixupDeps(ProjectCmdBase):
             install_dirs.append(inst_dir)
 
             if m == manifest:
-                dep_munger = create_dyn_dep_munger(loader.build_opts, install_dirs)
+                dep_munger = create_dyn_dep_munger(
+                    loader.build_opts, install_dirs, args.strip
+                )
                 dep_munger.process_deps(args.destdir, args.final_install_prefix)
 
     def setup_project_cmd_parser(self, parser):
@@ -580,6 +582,12 @@ class FixupDeps(ProjectCmdBase):
         parser.add_argument(
             "--final-install-prefix", help=("specify the final installation prefix")
         )
+        parser.add_argument(
+            "--strip",
+            action="store_true",
+            default=False,
+            help="Strip debug info while processing executables",
+        )
 
 
 @cmd("test", "test a given project")
@@ -757,8 +765,17 @@ jobs:
             )
 
             out.write("    - name: Copy artifacts\n")
+            if build_opts.is_linux():
+                # Strip debug info from the binaries, but only on linux.
+                # While the `strip` utility is also available on macOS,
+                # attempting to strip there results in an error.
+                # The `strip` utility is not available on Windows.
+                strip = " --strip"
+            else:
+                strip = ""
+
             out.write(
-                f"      run: {getdeps} fixup-dyn-deps "
+                f"      run: {getdeps} fixup-dyn-deps{strip} "
                 f"--src-dir=. {manifest.name} _artifacts/{job_name} {project_prefix} "
                 f"--final-install-prefix /usr/local\n"
             )

build/fbcode_builder/getdeps/dyndeps.py

@@ -27,10 +27,11 @@ def copyfile(src, dest):
 
 
 class DepBase(object):
-    def __init__(self, buildopts, install_dirs):
+    def __init__(self, buildopts, install_dirs, strip):
         self.buildopts = buildopts
         self.env = buildopts.compute_env_for_install_dirs(install_dirs)
         self.install_dirs = install_dirs
+        self.strip = strip
         self.processed_deps = set()
 
     def list_dynamic_deps(self, objfile):
@@ -111,6 +112,9 @@ class DepBase(object):
 
                 self.rewrite_dep(objfile, d, dep, dest_dep, final_lib_dir)
 
+        if self.strip:
+            self.strip_debug_info(objfile)
+
     def rewrite_dep(self, objfile, depname, old_dep, new_dep, final_lib_dir):
         raise RuntimeError("rewrite_dep not implemented")
 
@@ -143,10 +147,15 @@ class DepBase(object):
     def is_objfile(self, objfile):
         return True
 
+    def strip_debug_info(self, objfile):
+        """override this to define how to remove debug information
+        from an object file"""
+        pass
+
 
 class WinDeps(DepBase):
-    def __init__(self, buildopts, install_dirs):
-        super(WinDeps, self).__init__(buildopts, install_dirs)
+    def __init__(self, buildopts, install_dirs, strip):
+        super(WinDeps, self).__init__(buildopts, install_dirs, strip)
         self.dumpbin = self.find_dumpbin()
 
     def find_dumpbin(self):
@@ -308,8 +317,8 @@ try {{
 
 
 class ElfDeps(DepBase):
-    def __init__(self, buildopts, install_dirs):
-        super(ElfDeps, self).__init__(buildopts, install_dirs)
+    def __init__(self, buildopts, install_dirs, strip):
+        super(ElfDeps, self).__init__(buildopts, install_dirs, strip)
 
         # We need patchelf to rewrite deps, so ensure that it is built...
         subprocess.check_call([sys.executable, sys.argv[0], "build", "patchelf"])
@@ -350,6 +359,9 @@ class ElfDeps(DepBase):
             magic = f.read(4)
             return magic == b"\x7fELF"
 
+    def strip_debug_info(self, objfile):
+        subprocess.check_call(["strip", objfile])
+
 
 # MACH-O magic number
 MACH_MAGIC = 0xFEEDFACF
@@ -409,10 +421,10 @@ class MachDeps(DepBase):
         )
 
 
-def create_dyn_dep_munger(buildopts, install_dirs):
+def create_dyn_dep_munger(buildopts, install_dirs, strip=False):
     if buildopts.is_linux():
-        return ElfDeps(buildopts, install_dirs)
+        return ElfDeps(buildopts, install_dirs, strip)
     if buildopts.is_darwin():
-        return MachDeps(buildopts, install_dirs)
+        return MachDeps(buildopts, install_dirs, strip)
     if buildopts.is_windows():
-        return WinDeps(buildopts, install_dirs)
+        return WinDeps(buildopts, install_dirs, strip)