Add an option to preserve symbols and debug_frame.

New strip option named keep_symbols_and_debug_frame, that will keep the
symbols and the .debug_frame. This is meant for use by libc.so only on
arm32. Other libraries might want to use it to keep better unwinding
information on device.

Bug: 132992102

Test: Built libc.so with this option and verified that it contains
Test: the .debug_frame section.
Change-Id: I823a28199dec8316e8b26fe31ff9f17e6b11d406

cc/builder.go

@@ -254,11 +254,12 @@ type builderFlags struct {
 
 	groupStaticLibs bool
 
-	stripKeepSymbols       bool
-	stripKeepSymbolsList   string
-	stripKeepMiniDebugInfo bool
-	stripAddGnuDebuglink   bool
-	stripUseGnuStrip       bool
+	stripKeepSymbols              bool
+	stripKeepSymbolsList          string
+	stripKeepSymbolsAndDebugFrame bool
+	stripKeepMiniDebugInfo        bool
+	stripAddGnuDebuglink          bool
+	stripUseGnuStrip              bool
 
 	proto            android.ProtoFlags
 	protoC           bool
@@ -839,6 +840,9 @@ func TransformStrip(ctx android.ModuleContext, inputFile android.Path,
 	if flags.stripKeepSymbolsList != "" {
 		args += " -k" + flags.stripKeepSymbolsList
 	}
+	if flags.stripKeepSymbolsAndDebugFrame {
+		args += " --keep-symbols-and-debug-frame"
+	}
 	if flags.stripUseGnuStrip {
 		args += " --use-gnu-strip"
 	}

cc/strip.go

@@ -22,11 +22,12 @@ import (
 
 type StripProperties struct {
 	Strip struct {
-		None              *bool    `android:"arch_variant"`
-		All               *bool    `android:"arch_variant"`
-		Keep_symbols      *bool    `android:"arch_variant"`
-		Keep_symbols_list []string `android:"arch_variant"`
-		Use_gnu_strip     *bool    `android:"arch_variant"`
+		None                         *bool    `android:"arch_variant"`
+		All                          *bool    `android:"arch_variant"`
+		Keep_symbols                 *bool    `android:"arch_variant"`
+		Keep_symbols_list            []string `android:"arch_variant"`
+		Keep_symbols_and_debug_frame *bool    `android:"arch_variant"`
+		Use_gnu_strip                *bool    `android:"arch_variant"`
 	} `android:"arch_variant"`
 }
 
@@ -46,6 +47,8 @@ func (stripper *stripper) strip(ctx ModuleContext, in android.Path, out android.
 	} else {
 		if Bool(stripper.StripProperties.Strip.Keep_symbols) {
 			flags.stripKeepSymbols = true
+		} else if Bool(stripper.StripProperties.Strip.Keep_symbols_and_debug_frame) {
+			flags.stripKeepSymbolsAndDebugFrame = true
 		} else if len(stripper.StripProperties.Strip.Keep_symbols_list) > 0 {
 			flags.stripKeepSymbolsList = strings.Join(stripper.StripProperties.Strip.Keep_symbols_list, ",")
 		} else if !Bool(stripper.StripProperties.Strip.All) {