Merge changes from topic "musl_clang_runtimes"

* changes:
  Enable sanitizers for musl
  Switch to libunwind to remove dependency on libgcc for musl

cc/config/x86_linux_host.go

@@ -65,7 +65,6 @@ var (
 
 	linuxMuslLdflags = []string{
 		"-nostdlib",
-		"-lgcc", "-lgcc_eh",
 		"--sysroot /dev/null",
 	}
 

cc/sanitize.go

@@ -480,8 +480,8 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 		s.Diag.Cfi = nil
 	}
 
-	// Disable sanitizers that depend on the UBSan runtime for windows/darwin/musl builds.
-	if !ctx.Os().Linux() || ctx.Os() == android.LinuxMusl {
+	// Disable sanitizers that depend on the UBSan runtime for windows/darwin builds.
+	if !ctx.Os().Linux() {
 		s.Cfi = nil
 		s.Diag.Cfi = nil
 		s.Misc_undefined = nil
@@ -490,6 +490,12 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 		s.Integer_overflow = nil
 	}
 
+	// Disable CFI for musl
+	if ctx.toolchain().Musl() {
+		s.Cfi = nil
+		s.Diag.Cfi = nil
+	}
+
 	// Also disable CFI for VNDK variants of components
 	if ctx.isVndk() && ctx.useVndk() {
 		if ctx.static() {
@@ -702,10 +708,10 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {
 		flags.Local.AsFlags = append(flags.Local.AsFlags, sanitizeArg)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, sanitizeArg)
 
-		if ctx.toolchain().Bionic() {
-			// Bionic sanitizer runtimes have already been added as dependencies so that
-			// the right variant of the runtime will be used (with the "-android"
-			// suffix), so don't let clang the runtime library.
+		if ctx.toolchain().Bionic() || ctx.toolchain().Musl() {
+			// Bionic and musl sanitizer runtimes have already been added as dependencies so that
+			// the right variant of the runtime will be used (with the "-android" or "-musl"
+			// suffixes), so don't let clang the runtime library.
 			flags.Local.LdFlags = append(flags.Local.LdFlags, "-fno-sanitize-link-runtime")
 		} else {
 			// Host sanitizers only link symbols in the final executable, so
@@ -1217,7 +1223,7 @@ func sanitizerRuntimeMutator(mctx android.BottomUpMutatorContext) {
 			addStaticDeps(config.BuiltinsRuntimeLibrary(toolchain))
 		}
 
-		if runtimeLibrary != "" && (toolchain.Bionic() || c.sanitize.Properties.UbsanRuntimeDep) {
+		if runtimeLibrary != "" && (toolchain.Bionic() || toolchain.Musl() || c.sanitize.Properties.UbsanRuntimeDep) {
 			// UBSan is supported on non-bionic linux host builds as well
 
 			// Adding dependency to the runtime library. We are using *FarVariation*

rust/config/x86_linux_host.go

@@ -42,8 +42,6 @@ var (
 		"-nodefaultlibs",
 		"-nostdlib",
 		"-Wl,--no-dynamic-linker",
-		// for unwind
-		"-lgcc", "-lgcc_eh",
 	}
 	linuxX86Rustflags   = []string{}
 	linuxX86Linkflags   = []string{}