[cc_fuzz] Collect shared deps by name, not by module. (c0b442f8) · Commits · e / os / android_build_soong

cc_fuzz relies on an invariant that's not exactly true. We assume that for each fuzz target, we'll only have a dependency on a single sanitized variant of a shared library. In a few instances, this is proven not to be true, as we end up with a transitive dependency on a shared library with sanitizer coverage instrumentation, and one without sancov. This results in breaking the packaging for some fuzz targets. This then goes on to break `make haiku` in some scenarios. While this isn't a completely technically correct solution (as we basically resolve one of the sanitized variants pseduorandomly), it does resolve the issue for now. Realistically, we should select *both* of them, and set the DT_RUNPATHS on the shared libraries to point to the dependencies that have the sanitization that they're expecting. In practice - this shouldn't break sancov (we might just silently drop some coverage) or hwasan (we might just silently drop some hwasanification). I believe that the walk order of VisitDirectDeps is deterministic, and as such this shouldn't affect the reproducability of fuzz target builds (and thus won't blow up the Soong rebuilds). ccross@ or dwillemsen@ can speak better to this than I can though. Bug: 148306195 Bug: 151102177 Bug: 155123587 Test: lunch flame_hwasan-userdebug && make haiku Change-Id: I8d4001d93da33e4e5d21f740beb88a20fcc26e2a

cc/fuzz.go

+7 −7

Original line number	Diff line number	Diff line
		@@ -126,7 +126,7 @@ func (fuzz *fuzzBinary) linkerFlags(ctx ModuleContext, flags Flags) Flags {
		func collectAllSharedDependencies(ctx android.SingletonContext, module android.Module) android.Paths {
		var fringe []android.Module

		seen := make(map[android.Module]bool)
		seen := make(map[string]bool)

		// Enumerate the first level of dependencies, as we discard all non-library
		// modules in the BFS loop below.
		@@ -140,15 +140,15 @@ func collectAllSharedDependencies(ctx android.SingletonContext, module android.M

		for i := 0; i < len(fringe); i++ {
		module := fringe[i]
		if seen[module] {
		if seen[module.Name()] {
		continue
		}
		seen[module] = true
		seen[module.Name()] = true

		ccModule := module.(*Module)
		sharedLibraries = append(sharedLibraries, ccModule.UnstrippedOutputFile())
		ctx.VisitDirectDeps(module, func(dep android.Module) {
		if isValidSharedDependency(dep) && !seen[dep] {
		if isValidSharedDependency(dep) && !seen[dep.Name()] {
		fringe = append(fringe, dep)
		}
		})
		@@ -255,13 +255,13 @@ func (fuzz *fuzzBinary) install(ctx ModuleContext, file android.Path) {
		}

		// Grab the list of required shared libraries.
		seen := make(map[android.Module]bool)
		seen := make(map[string]bool)
		var sharedLibraries android.Paths
		ctx.WalkDeps(func(child, parent android.Module) bool {
		if seen[child] {
		if seen[child.Name()] {
		return false
		}
		seen[child] = true
		seen[child.Name()] = true

		if isValidSharedDependency(child) {
		sharedLibraries = append(sharedLibraries, child.(*Module).UnstrippedOutputFile())