rust: Remove libtest from stdlibs list

libtest does not need to be linked for every module type, so remove it
from the stdlibs list. Instead, link it only when building benchmarks or
tests.

Bug: 193782599
Test: cd external/rust/crates/; mma
Test: Rust tests still run correctly.
Merged-In: I536be8754da0987e09340744d9ebf668b8e734d0
Change-Id: I536be8754da0987e09340744d9ebf668b8e734d0

rust/benchmark.go

@@ -101,6 +101,7 @@ func (benchmark *benchmarkDecorator) compilerFlags(ctx ModuleContext, flags Flag
 func (benchmark *benchmarkDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
 	deps = benchmark.binaryDecorator.compilerDeps(ctx, deps)
 
+	deps.Rustlibs = append(deps.Rustlibs, "libtest")
 	deps.Rustlibs = append(deps.Rustlibs, "libcriterion")
 
 	return deps

rust/config/global.go

@@ -29,7 +29,6 @@ var (
 	DefaultEdition     = "2018"
 	Stdlibs            = []string{
 		"libstd",
-		"libtest",
 	}
 
 	// Mapping between Soong internal arch types and std::env constants.

rust/test.go

@@ -169,3 +169,11 @@ func RustTestHostFactory() android.Module {
 func (test *testDecorator) stdLinkage(ctx *depsContext) RustLinkage {
 	return RlibLinkage
 }
+
+func (test *testDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
+	deps = test.binaryDecorator.compilerDeps(ctx, deps)
+
+	deps.Rustlibs = append(deps.Rustlibs, "libtest")
+
+	return deps
+}

rust/testing.go

@@ -162,12 +162,10 @@ func GatherRequiredDepsForTest() string {
 			name: "libtest",
 			crate_name: "test",
 			srcs: ["foo.rs"],
-			no_stdlibs: true,
 			host_supported: true,
 			vendor_available: true,
 			vendor_ramdisk_available: true,
 			native_coverage: false,
-			sysroot: true,
 			apex_available: ["//apex_available:platform", "//apex_available:anyapex"],
 			min_sdk_version: "29",
 		}