Reland: Fix -Wl,--exclude-libs for clang runtime libraries

The sanitize code was assuming that the names of the clang runtime
library modules were the same as their static library output files,
but that's not true after I39e2cf8ae14edf8510276dab38011afaef85822c.
Use the dependency to get the name of the library to pass to
-Wl,--exclude-libs.

This relands If6ca7838800c76f90105fb02d39e8a68cec96314 with a fix
for skipping tests that don't work on mac.
   
Bug: 235624976
Test: TestUbsan
Change-Id: I32894d10d24473ad48b6afc5663f91fa48a6a0ba

cc/cc.go

@@ -95,6 +95,10 @@ type Deps struct {
 	HeaderLibs                                  []string
 	RuntimeLibs                                 []string
 
+	// UnexportedStaticLibs are static libraries that are also passed to -Wl,--exclude-libs= to
+	// prevent automatically exporting symbols.
+	UnexportedStaticLibs []string
+
 	// Used for data dependencies adjacent to tests
 	DataLibs []string
 	DataBins []string
@@ -156,6 +160,7 @@ type PathDeps struct {
 	GeneratedDeps    android.Paths
 
 	Flags                      []string
+	LdFlags                    []string
 	IncludeDirs                android.Paths
 	SystemIncludeDirs          android.Paths
 	ReexportedDirs             android.Paths
@@ -678,6 +683,9 @@ type libraryDependencyTag struct {
 
 	// Whether or not this dependency has to be followed for the apex variants
 	excludeInApex bool
+
+	// If true, don't automatically export symbols from the static library into a shared library.
+	unexportedSymbols bool
 }
 
 // header returns true if the libraryDependencyTag is tagging a header lib dependency.
@@ -1921,6 +1929,8 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 		flags.Local.CommonFlags = append(flags.Local.CommonFlags, "-isystem "+dir.String())
 	}
 
+	flags.Local.LdFlags = append(flags.Local.LdFlags, deps.LdFlags...)
+
 	c.flags = flags
 	// We need access to all the flags seen by a source file.
 	if c.sabi != nil {
@@ -2368,6 +2378,13 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 		}, depTag, RewriteSnapshotLib(lib, GetSnapshot(c, &snapshotInfo, actx).StaticLibs))
 	}
 
+	for _, lib := range deps.UnexportedStaticLibs {
+		depTag := libraryDependencyTag{Kind: staticLibraryDependency, Order: lateLibraryDependency, unexportedSymbols: true}
+		actx.AddVariationDependencies([]blueprint.Variation{
+			{Mutator: "link", Variation: "static"},
+		}, depTag, RewriteSnapshotLib(lib, GetSnapshot(c, &snapshotInfo, actx).StaticLibs))
+	}
+
 	for _, lib := range deps.LateSharedLibs {
 		if inList(lib, sharedLibNames) {
 			// This is to handle the case that some of the late shared libs (libc, libdl, libm, ...)
@@ -2866,6 +2883,10 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 						panic(fmt.Errorf("unexpected library dependency order %d", libDepTag.Order))
 					}
 				}
+				if libDepTag.unexportedSymbols {
+					depPaths.LdFlags = append(depPaths.LdFlags,
+						"-Wl,--exclude-libs="+staticLibraryInfo.StaticLibrary.Base())
+				}
 			}
 
 			if libDepTag.static() && !libDepTag.wholeStatic {

cc/linker.go

@@ -399,7 +399,7 @@ func (linker *baseLinker) linkerDeps(ctx DepsContext, deps Deps) Deps {
 	if ctx.toolchain().Bionic() {
 		// libclang_rt.builtins has to be last on the command line
 		if !Bool(linker.Properties.No_libcrt) && !ctx.header() {
-			deps.LateStaticLibs = append(deps.LateStaticLibs, config.BuiltinsRuntimeLibrary(ctx.toolchain()))
+			deps.UnexportedStaticLibs = append(deps.UnexportedStaticLibs, config.BuiltinsRuntimeLibrary(ctx.toolchain()))
 		}
 
 		if inList("libdl", deps.SharedLibs) {
@@ -422,7 +422,7 @@ func (linker *baseLinker) linkerDeps(ctx DepsContext, deps Deps) Deps {
 		}
 	} else if ctx.toolchain().Musl() {
 		if !Bool(linker.Properties.No_libcrt) && !ctx.header() {
-			deps.LateStaticLibs = append(deps.LateStaticLibs, config.BuiltinsRuntimeLibrary(ctx.toolchain()))
+			deps.UnexportedStaticLibs = append(deps.UnexportedStaticLibs, config.BuiltinsRuntimeLibrary(ctx.toolchain()))
 		}
 	}
 
@@ -530,10 +530,6 @@ func (linker *baseLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
 		}
 	}
 
-	if ctx.toolchain().LibclangRuntimeLibraryArch() != "" {
-		flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--exclude-libs="+config.BuiltinsRuntimeLibrary(ctx.toolchain())+".a")
-	}
-
 	CheckBadLinkerFlags(ctx, "ldflags", linker.Properties.Ldflags)
 
 	flags.Local.LdFlags = append(flags.Local.LdFlags, proptools.NinjaAndShellEscapeList(linker.Properties.Ldflags)...)

cc/sanitize.go

@@ -588,13 +588,6 @@ func toDisableUnsignedShiftBaseChange(flags []string) bool {
 }
 
 func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {
-	minimalRuntimeLib := config.UndefinedBehaviorSanitizerMinimalRuntimeLibrary(ctx.toolchain()) + ".a"
-
-	if sanitize.Properties.MinimalRuntimeDep {
-		flags.Local.LdFlags = append(flags.Local.LdFlags,
-			"-Wl,--exclude-libs,"+minimalRuntimeLib)
-	}
-
 	if !sanitize.Properties.SanitizerEnabled && !sanitize.Properties.UbsanRuntimeDep {
 		return flags
 	}
@@ -724,7 +717,6 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {
 
 		if enableMinimalRuntime(sanitize) {
 			flags.Local.CFlags = append(flags.Local.CFlags, strings.Join(minimalRuntimeFlags, " "))
-			flags.Local.LdFlags = append(flags.Local.LdFlags, "-Wl,--exclude-libs,"+minimalRuntimeLib)
 		}
 
 		if Bool(sanitize.Properties.Sanitize.Fuzzer) {
@@ -1217,7 +1209,7 @@ func sanitizerRuntimeMutator(mctx android.BottomUpMutatorContext) {
 			}
 
 			// static executable gets static runtime libs
-			depTag := libraryDependencyTag{Kind: staticLibraryDependency}
+			depTag := libraryDependencyTag{Kind: staticLibraryDependency, unexportedSymbols: true}
 			variations := append(mctx.Target().Variations(),
 				blueprint.Variation{Mutator: "link", Variation: "static"})
 			if c.Device() {

cc/sanitize_test.go

@@ -16,6 +16,7 @@ package cc
 
 import (
 	"fmt"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -201,6 +202,125 @@ func TestAsan(t *testing.T) {
 	t.Run("device", func(t *testing.T) { check(t, result, "android_arm64_armv8-a") })
 }
 
+func TestUbsan(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("requires linux")
+	}
+
+	bp := `
+		cc_binary {
+			name: "bin_with_ubsan",
+			host_supported: true,
+			shared_libs: [
+				"libshared",
+			],
+			static_libs: [
+				"libstatic",
+				"libnoubsan",
+			],
+			sanitize: {
+				undefined: true,
+			}
+		}
+
+		cc_binary {
+			name: "bin_depends_ubsan",
+			host_supported: true,
+			shared_libs: [
+				"libshared",
+			],
+			static_libs: [
+				"libstatic",
+				"libubsan",
+				"libnoubsan",
+			],
+		}
+
+		cc_binary {
+			name: "bin_no_ubsan",
+			host_supported: true,
+			shared_libs: [
+				"libshared",
+			],
+			static_libs: [
+				"libstatic",
+				"libnoubsan",
+			],
+		}
+
+		cc_library_shared {
+			name: "libshared",
+			host_supported: true,
+			shared_libs: ["libtransitive"],
+		}
+
+		cc_library_shared {
+			name: "libtransitive",
+			host_supported: true,
+		}
+
+		cc_library_static {
+			name: "libubsan",
+			host_supported: true,
+			sanitize: {
+				undefined: true,
+			}
+		}
+
+		cc_library_static {
+			name: "libstatic",
+			host_supported: true,
+		}
+
+		cc_library_static {
+			name: "libnoubsan",
+			host_supported: true,
+		}
+	`
+
+	result := android.GroupFixturePreparers(
+		prepareForCcTest,
+	).RunTestWithBp(t, bp)
+
+	check := func(t *testing.T, result *android.TestResult, variant string) {
+		staticVariant := variant + "_static"
+
+		minimalRuntime := result.ModuleForTests("libclang_rt.ubsan_minimal", staticVariant)
+
+		// The binaries, one with ubsan and one without
+		binWithUbsan := result.ModuleForTests("bin_with_ubsan", variant)
+		binDependsUbsan := result.ModuleForTests("bin_depends_ubsan", variant)
+		binNoUbsan := result.ModuleForTests("bin_no_ubsan", variant)
+
+		android.AssertStringListContains(t, "missing libclang_rt.ubsan_minimal in bin_with_ubsan static libs",
+			strings.Split(binWithUbsan.Rule("ld").Args["libFlags"], " "),
+			minimalRuntime.OutputFiles(t, "")[0].String())
+
+		android.AssertStringListContains(t, "missing libclang_rt.ubsan_minimal in bin_depends_ubsan static libs",
+			strings.Split(binDependsUbsan.Rule("ld").Args["libFlags"], " "),
+			minimalRuntime.OutputFiles(t, "")[0].String())
+
+		android.AssertStringListDoesNotContain(t, "unexpected libclang_rt.ubsan_minimal in bin_no_ubsan static libs",
+			strings.Split(binNoUbsan.Rule("ld").Args["libFlags"], " "),
+			minimalRuntime.OutputFiles(t, "")[0].String())
+
+		android.AssertStringListContains(t, "missing -Wl,--exclude-libs for minimal runtime in bin_with_ubsan",
+			strings.Split(binWithUbsan.Rule("ld").Args["ldFlags"], " "),
+			"-Wl,--exclude-libs="+minimalRuntime.OutputFiles(t, "")[0].Base())
+
+		android.AssertStringListContains(t, "missing -Wl,--exclude-libs for minimal runtime in bin_depends_ubsan static libs",
+			strings.Split(binDependsUbsan.Rule("ld").Args["ldFlags"], " "),
+			"-Wl,--exclude-libs="+minimalRuntime.OutputFiles(t, "")[0].Base())
+
+		android.AssertStringListDoesNotContain(t, "unexpected -Wl,--exclude-libs for minimal runtime in bin_no_ubsan static libs",
+			strings.Split(binNoUbsan.Rule("ld").Args["ldFlags"], " "),
+			"-Wl,--exclude-libs="+minimalRuntime.OutputFiles(t, "")[0].Base())
+	}
+
+	t.Run("host", func(t *testing.T) { check(t, result, result.Config.BuildOSTarget.String()) })
+	t.Run("device", func(t *testing.T) { check(t, result, "android_arm64_armv8-a") })
+}
+
 type MemtagNoteType int
 
 const (

cc/testing.go

@@ -73,7 +73,6 @@ func commonDefaultModules() string {
 			nocrt: true,
 			system_shared_libs: [],
 			stl: "none",
-			srcs: [""],
 			check_elf_files: false,
 			sanitize: {
 				never: true,
@@ -84,6 +83,7 @@ func commonDefaultModules() string {
 			name: "libcompiler_rt-extras",
 			defaults: ["toolchain_libs_defaults"],
 			vendor_ramdisk_available: true,
+			srcs: [""],
 		}
 
 		cc_prebuilt_library_static {
@@ -93,11 +93,13 @@ func commonDefaultModules() string {
 	        vendor_available: true,
 			vendor_ramdisk_available: true,
 			native_bridge_supported: true,
+			srcs: [""],
 		}
 
 		cc_prebuilt_library_shared {
 			name: "libclang_rt.hwasan",
 			defaults: ["toolchain_libs_defaults"],
+			srcs: [""],
 		}
 
 		cc_prebuilt_library_static {
@@ -108,6 +110,7 @@ func commonDefaultModules() string {
 			],
 			vendor_ramdisk_available: true,
 			native_bridge_supported: true,
+			srcs: [""],
 		}
 
 		cc_prebuilt_library_static {
@@ -116,17 +119,34 @@ func commonDefaultModules() string {
 				"linux_bionic_supported",
 				"toolchain_libs_defaults",
 			],
+			srcs: [""],
 		}
 
 		// Needed for sanitizer
 		cc_prebuilt_library_shared {
 			name: "libclang_rt.ubsan_standalone",
 			defaults: ["toolchain_libs_defaults"],
+			srcs: [""],
 		}
 
 		cc_prebuilt_library_static {
 			name: "libclang_rt.ubsan_minimal",
 			defaults: ["toolchain_libs_defaults"],
+			host_supported: true,
+			target: {
+				android_arm64: {
+					srcs: ["libclang_rt.ubsan_minimal.android_arm64.a"],
+				},
+				android_arm: {
+					srcs: ["libclang_rt.ubsan_minimal.android_arm.a"],
+				},
+				linux_glibc_x86_64: {
+					srcs: ["libclang_rt.ubsan_minimal.x86_64.a"],
+				},
+				linux_glibc_x86: {
+					srcs: ["libclang_rt.ubsan_minimal.x86.a"],
+				},
+			},
 		}
 
 		cc_library {
@@ -546,6 +566,11 @@ var PrepareForTestWithCcDefaultModules = android.GroupFixturePreparers(
 		"defaults/cc/common/crtend_so.c":            nil,
 		"defaults/cc/common/crtend.c":               nil,
 		"defaults/cc/common/crtbrand.c":             nil,
+
+		"defaults/cc/common/libclang_rt.ubsan_minimal.android_arm64.a": nil,
+		"defaults/cc/common/libclang_rt.ubsan_minimal.android_arm.a":   nil,
+		"defaults/cc/common/libclang_rt.ubsan_minimal.x86_64.a":        nil,
+		"defaults/cc/common/libclang_rt.ubsan_minimal.x86.a":           nil,
 	}.AddToFixture(),
 
 	// Place the default cc test modules that are common to all platforms in a location that will not