Add basic NDK STL link type check.

Test: make native
Bug: None
Change-Id: If883fade38c837839857d82f294c459b0dae1ce0

cc/cc.go

@@ -1036,6 +1036,27 @@ func checkLinkType(ctx android.ModuleContext, from *Module, to *Module) {
 		ctx.ModuleErrorf("links %q built against newer API version %q",
 			ctx.OtherModuleName(to), String(to.Properties.Sdk_version))
 	}
+
+	// Also check that the two STL choices are compatible.
+	fromStl := from.stl.Properties.SelectedStl
+	toStl := to.stl.Properties.SelectedStl
+	if fromStl == "" || toStl == "" {
+		// Libraries that don't use the STL are unrestricted.
+		return
+	}
+
+	if fromStl == "ndk_system" || toStl == "ndk_system" {
+		// We can be permissive with the system "STL" since it is only the C++
+		// ABI layer, but in the future we should make sure that everyone is
+		// using either libc++ or nothing.
+		return
+	}
+
+	if getNdkStlFamily(ctx, from) != getNdkStlFamily(ctx, to) {
+		ctx.ModuleErrorf("uses %q and depends on %q which uses incompatible %q",
+			from.stl.Properties.SelectedStl, ctx.OtherModuleName(to),
+			to.stl.Properties.SelectedStl)
+	}
 }
 
 // Convert dependencies to paths.  Returns a PathDeps containing paths

cc/stl.go

@@ -19,6 +19,25 @@ import (
 	"fmt"
 )
 
+func getNdkStlFamily(ctx android.ModuleContext, m *Module) string {
+	stl := m.stl.Properties.SelectedStl
+	switch stl {
+	case "ndk_libc++_shared", "ndk_libc++_static":
+		return "libc++"
+	case "ndk_libstlport_shared", "ndk_libstlport_static":
+		return "stlport"
+	case "ndk_libgnustl_static":
+		return "gnustl"
+	case "ndk_system":
+		return "system"
+	case "":
+		return "none"
+	default:
+		ctx.ModuleErrorf("stl: %q is not a valid STL", stl)
+		return ""
+	}
+}
+
 type StlProperties struct {
 	// select the STL library to use.  Possible values are "libc++", "libc++_static",
 	// "stlport", "stlport_static", "ndk", "libstdc++", or "none".  Leave blank to select the