getdeps: dynamic dependency munging

Summary:
This diff adds a `fixup-dyn-deps` subcommand that is intended to
aid in packaging on multiple platforms.

Its purpose is to copy a set of executable object files from the getdeps
installation directories and place them into an installation staging
area that will then be used to create some kind of package (rpm, tarball etc.).

The dynamic dependencies of the executables are determined and also copied
into the destination area, and the important part: the execute is rewritten
such that it will load the deps out of an alternate installation prefix.

The implementation of this command draws on similar scripts in use for
the watchman and eden packaging on windows and macos.  This diff adds
linux support using the `patchelf` utility.

Reviewed By: pkaush

Differential Revision: D16101902

fbshipit-source-id: 5885125971947139407841e08c0cf9f35fdf5895

build/fbcode_builder/getdeps.py

@@ -16,6 +16,7 @@ import subprocess
 import sys
 
 from getdeps.buildopts import setup_build_options
+from getdeps.dyndeps import create_dyn_dep_munger
 from getdeps.errors import TransientFailure
 from getdeps.load import load_project, manifests_in_dependency_order
 from getdeps.manifest import ManifestParser
@@ -307,6 +308,64 @@ class BuildCmd(SubCmd):
         )
 
 
+@cmd("fixup-dyn-deps", "Adjusts dynamic dependencies for packaging purposes")
+class FixupDeps(SubCmd):
+    def run(self, args):
+        opts = setup_build_options(args)
+
+        manifest = load_project(opts, args.project)
+
+        ctx = context_from_host_tuple(facebook_internal=args.facebook_internal)
+        projects = manifests_in_dependency_order(opts, manifest, ctx)
+        manifests_by_name = {m.name: m for m in projects}
+
+        # Accumulate the install directories so that the build steps
+        # can find their dep installation
+        install_dirs = []
+
+        for m in projects:
+            ctx = dict(ctx)
+            if args.enable_tests and m.name == manifest.name:
+                ctx["test"] = "on"
+            else:
+                ctx["test"] = "off"
+            fetcher = m.create_fetcher(opts, ctx)
+
+            dirs = opts.compute_dirs(m, fetcher, manifests_by_name, ctx)
+            inst_dir = dirs["inst_dir"]
+
+            install_dirs.append(inst_dir)
+
+            if m == manifest:
+                dep_munger = create_dyn_dep_munger(opts, install_dirs)
+                dep_munger.process_deps(args.destdir, args.final_install_prefix)
+
+    def setup_parser(self, parser):
+        parser.add_argument(
+            "project",
+            help=(
+                "name of the project or path to a manifest "
+                "file describing the project"
+            ),
+        )
+        parser.add_argument("destdir", help=("Where to copy the fixed up executables"))
+        parser.add_argument(
+            "--final-install-prefix", help=("specify the final installation prefix")
+        )
+        parser.add_argument(
+            "--enable-tests",
+            action="store_true",
+            default=False,
+            help=(
+                "For the named project, build tests so that the test command "
+                "is able to execute tests"
+            ),
+        )
+        parser.add_argument(
+            "--schedule-type", help="Indicates how the build was activated"
+        )
+
+
 @cmd("test", "test a given project")
 class TestCmd(SubCmd):
     def run(self, args):