rust: Package shared libraries with fuzzer zips

Rust fuzzers were not packaging up their CC shared dependencies.
This would lead to fuzzers using the shared libraries included on
system, which may not be sanitized, leading to incorrect behavior.

This refactors the relevant code from CC and calls it from the Rust
build logic.

Bug: 202282599
Test: output rust fuzzer zip file includes shared dependencies.
Change-Id: I92196eb0141733797a67eae24f8e9aedea94c3bc

fuzz/fuzz_common.go

@@ -42,8 +42,9 @@ type FuzzModule struct {
 }
 
 type FuzzPackager struct {
-	Packages    android.Paths
-	FuzzTargets map[string]bool
+	Packages                android.Paths
+	FuzzTargets             map[string]bool
+	SharedLibInstallStrings []string
 }
 
 type FileToZip struct {
@@ -251,3 +252,42 @@ func (s *FuzzPackager) PreallocateSlice(ctx android.MakeVarsContext, targets str
 	sort.Strings(fuzzTargets)
 	ctx.Strict(targets, strings.Join(fuzzTargets, " "))
 }
+
+// CollectAllSharedDependencies performs a breadth-first search over the provided module's
+// dependencies using `visitDirectDeps` to enumerate all shared library
+// dependencies. We require breadth-first expansion, as otherwise we may
+// incorrectly use the core libraries (sanitizer runtimes, libc, libdl, etc.)
+// from a dependency. This may cause issues when dependencies have explicit
+// sanitizer tags, as we may get a dependency on an unsanitized libc, etc.
+func CollectAllSharedDependencies(ctx android.SingletonContext, module android.Module, unstrippedOutputFile func(module android.Module) android.Path, isValidSharedDependency func(dependency android.Module) bool) android.Paths {
+	var fringe []android.Module
+
+	seen := make(map[string]bool)
+
+	// Enumerate the first level of dependencies, as we discard all non-library
+	// modules in the BFS loop below.
+	ctx.VisitDirectDeps(module, func(dep android.Module) {
+		if isValidSharedDependency(dep) {
+			fringe = append(fringe, dep)
+		}
+	})
+
+	var sharedLibraries android.Paths
+
+	for i := 0; i < len(fringe); i++ {
+		module := fringe[i]
+		if seen[module.Name()] {
+			continue
+		}
+		seen[module.Name()] = true
+
+		sharedLibraries = append(sharedLibraries, unstrippedOutputFile(module))
+		ctx.VisitDirectDeps(module, func(dep android.Module) {
+			if isValidSharedDependency(dep) && !seen[dep.Name()] {
+				fringe = append(fringe, dep)
+			}
+		})
+	}
+
+	return sharedLibraries
+}