Merge changes from topic 'std'

* changes:
  Allow disabling gnu extensions
  Consolidate -std flags

cc/compiler.go

@@ -84,6 +84,9 @@ type BaseCompilerProperties struct {
 	// pass -frtti instead of -fno-rtti
 	Rtti *bool
 
+	// if set to false, use -std=c++* instead of -std=gnu++*
+	Gnu_extensions *bool
+
 	Debug, Release struct {
 		// list of module-specific flags that will be used for C and C++ compiles in debug or
 		// release builds
@@ -278,13 +281,27 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 	}
 
 	if !ctx.sdk() {
-		if ctx.Host() && !flags.Clang {
+		cStd := config.CStdVersion
+		cppStd := config.CppStdVersion
+
+		if !flags.Clang {
+			// GCC uses an invalid C++14 ABI (emits calls to
+			// __cxa_throw_bad_array_length, which is not a valid C++ RT ABI).
+			// http://b/25022512
+			cppStd = config.GccCppStdVersion
+		} else if ctx.Host() && !flags.Clang {
 			// The host GCC doesn't support C++14 (and is deprecated, so likely
 			// never will). Build these modules with C++11.
-			flags.CppFlags = append(flags.CppFlags, "-std=gnu++11")
-		} else {
-			flags.CppFlags = append(flags.CppFlags, "-std=gnu++14")
+			cppStd = config.GccCppStdVersion
 		}
+
+		if compiler.Properties.Gnu_extensions != nil && *compiler.Properties.Gnu_extensions == false {
+			cStd = gnuToCReplacer.Replace(cStd)
+			cppStd = gnuToCReplacer.Replace(cppStd)
+		}
+
+		flags.ConlyFlags = append([]string{"-std=" + cStd}, flags.ConlyFlags...)
+		flags.CppFlags = append([]string{"-std=" + cppStd}, flags.CppFlags...)
 	}
 
 	// We can enforce some rules more strictly in the code we own. strict
@@ -306,6 +323,8 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 	return flags
 }
 
+var gnuToCReplacer = strings.NewReplacer("gnu", "c")
+
 func ndkPathDeps(ctx ModuleContext) android.Paths {
 	if ctx.sdk() {
 		// The NDK sysroot timestamp file depends on all the NDK sysroot files

cc/config/global.go

@@ -37,9 +37,7 @@ var (
 		"-UDEBUG",
 	}
 
-	commonGlobalConlyflags = []string{
-		"-std=gnu99",
-	}
+	commonGlobalConlyflags = []string{}
 
 	deviceGlobalCflags = []string{
 		"-fdiagnostics-color",
@@ -66,6 +64,10 @@ var (
 	IllegalFlags = []string{
 		"-w",
 	}
+
+	CStdVersion      = "gnu99"
+	CppStdVersion    = "gnu++14"
+	GccCppStdVersion = "gnu++11"
 )
 
 var pctx = android.NewPackageContext("android/soong/cc/config")

cc/makevars.go

@@ -48,6 +48,10 @@ func makeVarsProvider(ctx android.MakeVarsContext) {
 	ctx.Strict("ADDRESS_SANITIZER_CONFIG_EXTRA_LDFLAGS", asanLdflags)
 	ctx.Strict("ADDRESS_SANITIZER_CONFIG_EXTRA_STATIC_LIBRARIES", asanLibs)
 
+	ctx.Strict("DEFAULT_C_STD_VERSION", config.CStdVersion)
+	ctx.Strict("DEFAULT_CPP_STD_VERSION", config.CppStdVersion)
+	ctx.Strict("DEFAULT_GCC_CPP_STD_VERSION", config.GccCppStdVersion)
+
 	includeFlags, err := ctx.Eval("${config.CommonGlobalIncludes} ${config.CommonGlobalSystemIncludes}")
 	if err != nil {
 		panic(err)