"bootstrap: true" modules are using bootstrap Bionic

If the bootstrap property is set to true, a binary configured to refer
to the bootstrap linker at /system/bin/bootstrap/linker[64]. This is for
very early processes that are executed before the init makes the linker
by bind-mounting it.

Bug: 120266448
Test: m init_second_stage and use readelf on the built file
DT_INTERP is set to /system/bin/bootstrap/linker64 and

Change-Id: I67487701192f127679cc8127ddc9f53e102ba9c4

cc/binary.go

@@ -249,7 +249,11 @@ func (binary *binaryDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags
 				} else {
 					switch ctx.Os() {
 					case android.Android:
-						flags.DynamicLinker = "/system/bin/linker"
+						if ctx.bootstrap() {
+							flags.DynamicLinker = "/system/bin/bootstrap/linker"
+						} else {
+							flags.DynamicLinker = "/system/bin/linker"
+						}
 						if flags.Toolchain.Is64Bit() {
 							flags.DynamicLinker += "64"
 						}

cc/cc.go

@@ -261,6 +261,7 @@ type ModuleContextIntf interface {
 	apexName() string
 	hasStubsVariants() bool
 	isStubs() bool
+	bootstrap() bool
 }
 
 type ModuleContext interface {
@@ -571,6 +572,10 @@ func (c *Module) HasStubsVariants() bool {
 	return false
 }
 
+func (c *Module) bootstrap() bool {
+	return Bool(c.Properties.Bootstrap)
+}
+
 type baseModuleContext struct {
 	android.BaseContext
 	moduleContextImpl
@@ -741,6 +746,10 @@ func (ctx *moduleContextImpl) isStubs() bool {
 	return ctx.mod.IsStubs()
 }
 
+func (ctx *moduleContextImpl) bootstrap() bool {
+	return ctx.mod.bootstrap()
+}
+
 func newBaseModule(hod android.HostOrDeviceSupported, multilib android.Multilib) *Module {
 	return &Module{
 		hod:      hod,
@@ -1553,7 +1562,7 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 					// If not building for APEX, use stubs only when it is from
 					// an APEX (and not from platform)
 					useThisDep = (depInPlatform != depIsStubs)
-					if c.inRecovery() || Bool(c.Properties.Bootstrap) {
+					if c.inRecovery() || c.bootstrap() {
 						// However, for recovery or bootstrap modules,
 						// always link to non-stub variant
 						useThisDep = !depIsStubs