Allow linker scripts when building objects.

Test: m nothing
Test: TreeHugger
Bug: 134581881
Bug: 137267623

Change-Id: If1422372585ec032a9e36eab73a04e98fe1c1b6c

cc/object.go

@@ -33,6 +33,20 @@ type objectLinker struct {
 	Properties ObjectLinkerProperties
 }
 
+type ObjectLinkerProperties struct {
+	// list of modules that should only provide headers for this module.
+	Header_libs []string `android:"arch_variant,variant_prepend"`
+
+	// names of other cc_object modules to link into this module using partial linking
+	Objs []string `android:"arch_variant"`
+
+	// if set, add an extra objcopy --prefix-symbols= step
+	Prefix_symbols *string
+
+	// if set, the path to a linker script to pass to ld -r when combining multiple object files.
+	Linker_script *string `android:"path,arch_variant"`
+}
+
 // cc_object runs the compiler without running the linker. It is rarely
 // necessary, but sometimes used to generate .s files from .c files to use as
 // input to a cc_genrule module.
@@ -71,9 +85,13 @@ func (object *objectLinker) linkerDeps(ctx DepsContext, deps Deps) Deps {
 	return deps
 }
 
-func (*objectLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
+func (object *objectLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
 	flags.LdFlags = append(flags.LdFlags, ctx.toolchain().ToolchainClangLdflags())
 
+	if lds := android.OptionalPathForModuleSrc(ctx, object.Properties.Linker_script); lds.Valid() {
+		flags.LdFlags = append(flags.LdFlags, "-Wl,-T,"+lds.String())
+		flags.LdFlagsDeps = append(flags.LdFlagsDeps, lds.Path())
+	}
 	return flags
 }