include dep in symlink tree if lib output style is shared

Summary:
NOTE: `runtime_dependency_handling` hasn't been used yet, so this will not impact existing builds.

As discussed previously (see bottom of diff summary), compilation is broken under some scenarios when `runtime_dependency_handling = "symlink"`, which will prevent this setting from being rolled out unconditionally (or at least more broadly) across arvr.

I think I figured out why and how to fix it.

Looking at this table (the cells are the lib_output_style):

    --------------------------------------------------------------
    | preferred_linkage |              link_strategy             |
    |                   |----------------------------------------|
    |                   | static   | static_pic   |   shared     |
    -------------------------------------------------------------|
    |      static       | *archive | *pic_archive | *pic_archive |
    |      shared       | shared   |   shared     |   shared     |
    |       any         | *archive | *pic_archive |   shared     |
    --------------------------------------------------------------

I think this is the behavior we want:

```
if lib_output_style is shared:
    include all shlibs in symlink tree
```

Whereas we are are currently doing:

```
if runtime_dependency_handling is symlink or link_strategy is shared:
    include all shlibs in symlink tree
```

This row is problematic under the current implementation:

    --------------------------------------------------------------
    | preferred_linkage |              link_strategy             |
    |                   |----------------------------------------|
    |                   | static   | static_pic   |   shared     |
    -------------------------------------------------------------|
    |       any         | *archive | *pic_archive |   shared     |
    --------------------------------------------------------------

If link_strategy is *not* shared, then the archive or pic_archive version of the library is linked. If runtime_dependency_handling is set to symlink mode, then the shared library will *also* be included in the symlink tree, which seems to break the compilation.

To fix this, we can look at the lib_output_style of each dependency to determine what is included in the symlink tree instead of using just the link strategy.

Reviewed By: jtbraun

Differential Revision: D67610026

fbshipit-source-id: f44da42372197ed3e6f23b9cb7dd390d57ffd7a4

prelude/cxx/cxx_executable.bzl

@@ -27,6 +27,10 @@ load(
     "@prelude//cxx:cxx_bolt.bzl",
     "cxx_use_bolt",
 )
+load(
+    "@prelude//cxx:cxx_toolchain_types.bzl",
+    "PicBehavior",
+)
 load(
     "@prelude//cxx:link_groups_types.bzl",
     "LinkGroupsDebugLinkInfo",
@@ -56,13 +60,15 @@ load(
 )
 load(
     "@prelude//linking:link_info.bzl",
+    "LibOutputStyle",
     "LinkArgs",
     "LinkCommandDebugOutput",
     "LinkInfo",
     "LinkOrdering",  # @unused Used as a type
     "LinkStrategy",
     "LinkedObject",  # @unused Used as a type
     "ObjectsLinkable",
+    "get_lib_output_style",
     "make_link_command_debug_output",
     "make_link_command_debug_output_json_info",
     "to_link_strategy",
@@ -515,11 +521,19 @@ def cxx_executable(ctx: AnalysisContext, impl_params: CxxRuleConstructorParams,
     # Only setup a shared library symlink tree when shared linkage or link_groups is used
     gnu_use_link_groups = cxx_is_gnu(ctx) and len(link_group_mappings) > 0
     shlib_deps = []
-    if impl_params.runtime_dependency_handling == RuntimeDependencyHandling("symlink") or link_strategy == LinkStrategy("shared") or gnu_use_link_groups:
+    if link_strategy == LinkStrategy("shared") or gnu_use_link_groups:
         shlib_deps = (
             [d.shared_library_info for d in link_deps] +
             [d.shared_library_info for d in impl_params.extra_link_roots]
         )
+    elif impl_params.runtime_dependency_handling == RuntimeDependencyHandling("symlink"):
+        for d in link_deps + impl_params.extra_link_roots:
+            if d.linkable_graph == None:
+                continue
+            preferred_linkage = d.linkable_graph.nodes.value.linkable.preferred_linkage
+            output_style = get_lib_output_style(link_strategy, preferred_linkage, PicBehavior("supported"))
+            if output_style == LibOutputStyle("shared_lib"):
+                shlib_deps.append(d.shared_library_info)
 
     shlib_info = merge_shared_libraries(ctx.actions, deps = shlib_deps)