wip: generate linker sections

newt/builder/extcmd.go

@@ -184,6 +184,39 @@ func (t *TargetBuilder) execExtCmds(sf stage.StageFunc, userSrcDir string,
 	return nil
 }
 
+func getSectionEntry(name string, dest string) string {
+	entry := "." + name + " : \n" + "{ \n\t" + "__" + name + "_start__ = .;\n\t" +
+		"*(." + name + ")\n\t" +
+		"__" + name + "_end__ = .;\n" +
+		"} > " + dest + "\n\n"
+
+	return entry
+}
+
+func (t *TargetBuilder) generateSectionHeaders() {
+	var s []string
+
+	for _, pkg := range t.res.LpkgRpkgMap {
+		s = append(s, pkg.Lpkg.Sections()...)
+	}
+
+	if len(s) == 0 {
+		return
+	}
+
+	ram_header, err := os.Create(GeneratedIncludeDir(t.target.FullName()) + "/ld_ram.h")
+	text_header, err := os.Create(GeneratedIncludeDir(t.target.FullName()) + "/ld_text.h")
+	if err != nil {
+		return
+	}
+
+	for _, section := range s {
+		ram_header.WriteString(getSectionEntry(section, "RAM"))
+		text_header.WriteString(getSectionEntry(section, "TEXT"))
+	}
+
+}
+
 // execPreBuildCmds runs the target's set of pre-build user commands.  It is an
 // error if any command fails (exits with a nonzero status).
 func (t *TargetBuilder) execPreBuildCmds(workDir string) error {

newt/builder/targetbuild.go

@@ -581,6 +581,8 @@ func (t *TargetBuilder) Build() error {
 		os.RemoveAll(workDir)
 	}()
 
+	t.generateSectionHeaders()
+
 	// Execute the set of pre-build user scripts.
 	if err := t.execPreBuildCmds(workDir); err != nil {
 		return err

newt/pkg/localpackage.go

@@ -59,6 +59,8 @@ type LocalPackage struct {
 	// General information about the package
 	desc *PackageDesc
 
+	sections []string
+
 	// Extra package-specific settings that don't come from syscfg.  For
 	// example, SELFTEST gets set when the newt test command is used.
 	injectedSettings *cfgv.Settings
@@ -145,6 +147,10 @@ func (pkg *LocalPackage) Desc() *PackageDesc {
 	return pkg.desc
 }
 
+func (pkg *LocalPackage) Sections() []string {
+	return pkg.sections
+}
+
 func (pkg *LocalPackage) SetName(name string) {
 	pkg.name = name
 }
@@ -197,6 +203,15 @@ func (pkg *LocalPackage) readDesc(yc ycfg.YCfg) (*PackageDesc, error) {
 	return pdesc, nil
 }
 
+func (pkg *LocalPackage) readSections(yc ycfg.YCfg) ([]string, error) {
+	var err error
+
+	sections, err := yc.GetValStringSlice("pkg.sections", nil)
+	util.OneTimeWarningError(err)
+
+	return sections, nil
+}
+
 func (pkg *LocalPackage) sequenceString(key string) string {
 	var buffer bytes.Buffer
 
@@ -361,6 +376,8 @@ func (pkg *LocalPackage) Load() error {
 		return err
 	}
 
+	pkg.sections, err = pkg.readSections(pkg.PkgY)
+
 	// Load syscfg settings.
 	pkg.SyscfgY, err = config.ReadFile(pkg.SyscfgYamlPath())
 	if err != nil && !util.IsNotExist(err) {