newt: Add pkg.ign_pkgs to skip certain packages when linking

newt/builder/build.go

@@ -26,6 +26,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 
 	log "github.com/sirupsen/logrus"
 
@@ -416,18 +417,32 @@ func (b *Builder) link(elfName string, linkerScripts []string,
 		if err != nil {
 			return err
 		}
-		c.AddInfo(&toolchain.CompilerInfo{Lflags: ci.Lflags})
+		c.AddInfo(&toolchain.CompilerInfo{
+			Lflags: ci.Lflags, IgnorePkgs: ci.IgnorePkgs})
 	}
 	dirs = append(dirs, extraADirs...)
 
-	// Find all .a files in the input directories.
+	// Find all .a files in the input directories for all non-ignored packages
+	ignorePkgs := c.GetCompilerInfo().IgnorePkgs
 	trimmedANames := []string{}
 	for _, dir := range dirs {
-		fullANames, _ := filepath.Glob(dir + "/*.a")
-		for i, archiveName := range fullANames {
-			fullANames[i] = filepath.ToSlash(archiveName)
+		ignoreThisPkg := false
+		for i, ignorePkg := range ignorePkgs {
+			if strings.HasSuffix(dir, ignorePkg.String()) {
+				// Pop the ignore package to speed up subsequent checks.
+				// Assumes no duplicate packages.
+				ignorePkgs[i] = ignorePkgs[len(ignorePkgs)-1]
+				ignorePkgs = ignorePkgs[:len(ignorePkgs)-1]
+				ignoreThisPkg = true
+			}
+		}
+		if !ignoreThisPkg {
+			fullANames, _ := filepath.Glob(dir + "/*.a")
+			for i, archiveName := range fullANames {
+				fullANames[i] = filepath.ToSlash(archiveName)
+			}
+			trimmedANames = append(trimmedANames, fullANames...)
 		}
-		trimmedANames = append(trimmedANames, fullANames...)
 	}
 
 	c.LinkerScripts = linkerScripts

newt/builder/buildpackage.go

@@ -198,6 +198,21 @@ func (bpkg *BuildPackage) CompilerInfo(
 		ci.IgnoreDirs = append(ci.IgnoreDirs, re)
 	}
 
+	ci.IgnorePkgs = []*regexp.Regexp{}
+
+	ignPkgs, err := bpkg.rpkg.Lpkg.PkgY.GetValStringSlice(
+		"pkg.ign_pkgs", settings)
+	util.OneTimeWarningError(err)
+
+	for _, str := range ignPkgs {
+		re, err := regexp.Compile(str)
+		if err != nil {
+			return nil, util.NewNewtError(
+				"Ignore pkgs, unable to compile re: " + err.Error())
+		}
+		ci.IgnorePkgs = append(ci.IgnorePkgs, re)
+	}
+
 	bpkg.SourceDirectories, err = bpkg.rpkg.Lpkg.PkgY.GetValStringSlice(
 		"pkg.src_dirs", settings)
 	util.OneTimeWarningError(err)

newt/toolchain/compiler.go

@@ -59,6 +59,7 @@ type CompilerInfo struct {
 	Aflags      []string
 	IgnoreFiles []*regexp.Regexp
 	IgnoreDirs  []*regexp.Regexp
+	IgnorePkgs  []*regexp.Regexp
 }
 
 type CompileCommand struct {
@@ -166,6 +167,7 @@ func NewCompilerInfo() *CompilerInfo {
 	ci.Aflags = []string{}
 	ci.IgnoreFiles = []*regexp.Regexp{}
 	ci.IgnoreDirs = []*regexp.Regexp{}
+	ci.IgnorePkgs = []*regexp.Regexp{}
 
 	return ci
 }
@@ -246,6 +248,7 @@ func (ci *CompilerInfo) AddCompilerInfo(newCi *CompilerInfo) {
 	ci.Aflags = addFlags("aflag", ci.Aflags, newCi.Aflags)
 	ci.IgnoreFiles = append(ci.IgnoreFiles, newCi.IgnoreFiles...)
 	ci.IgnoreDirs = append(ci.IgnoreDirs, newCi.IgnoreDirs...)
+	ci.IgnorePkgs = append(ci.IgnorePkgs, newCi.IgnorePkgs...)
 }
 
 func NewCompiler(compilerDir string, dstDir string,