cmd/go: handle cgo pkg-config pragmas

Fixes #2681.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5540047

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index f0078a36c8c42e716333e8fc7357b1eb9c9120fe..71b606d76e0c4b5eb81e5296898dba6db563f44f 100644 (file)
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -794,13 +794,8 @@ func (b *builder) showcmd(dir string, format string, args ...interface{}) {
 // showOutput also replaces references to the work directory with $WORK.
 //
 func (b *builder) showOutput(dir, desc, out string) {
-       prefix := "# " + desc
-       suffix := "\n" + out
-       pwd, _ := os.Getwd()
-       if reldir, err := filepath.Rel(pwd, dir); err == nil && len(reldir) < len(dir) {
-               suffix = strings.Replace(suffix, " "+dir, " "+reldir, -1)
-               suffix = strings.Replace(suffix, "\n"+dir, "\n"+reldir, -1)
-       }
+       prefix := "# " + desc + "\n"
+       suffix := relPaths(dir, out)
        suffix = strings.Replace(suffix, " "+b.work, " $WORK", -1)
 
        b.output.Lock()
@@ -808,6 +803,18 @@ func (b *builder) showOutput(dir, desc, out string) {
        fmt.Print(prefix, suffix)
 }
 
+// relPaths returns a copy of out with references to dir
+// made relative to the current directory if that would be shorter.
+func relPaths(dir, out string) string {
+       x := "\n" + out
+       pwd, _ := os.Getwd()
+       if reldir, err := filepath.Rel(pwd, dir); err == nil && len(reldir) < len(dir) {
+               x = strings.Replace(x, " "+dir, " "+reldir, -1)
+               x = strings.Replace(x, "\n"+dir, "\n"+reldir, -1)
+       }
+       return x[1:]
+}
+
 // errPrintedOutput is a special error indicating that a command failed
 // but that it generated output as well, and that output has already
 // been printed, so there's no point showing 'exit status 1' or whatever
@@ -819,11 +826,30 @@ var errPrintedOutput = errors.New("already printed output - no need to show erro
 // If the commnd fails, run prints information about the failure
 // and returns a non-nil error.
 func (b *builder) run(dir string, desc string, cmdargs ...interface{}) error {
+       out, err := b.runOut(dir, desc, cmdargs...)
+       if len(out) > 0 {
+               if out[len(out)-1] != '\n' {
+                       out = append(out, '\n')
+               }
+               if desc == "" {
+                       desc = b.fmtcmd(dir, "%s", strings.Join(stringList(cmdargs...), " "))
+               }
+               b.showOutput(dir, desc, string(out))
+               if err != nil {
+                       err = errPrintedOutput
+               }
+       }
+       return err
+}
+
+// runOut runs the command given by cmdline in the directory dir.
+// It returns the command output and any errors that occurred.
+func (b *builder) runOut(dir string, desc string, cmdargs ...interface{}) ([]byte, error) {
        cmdline := stringList(cmdargs...)
        if buildN || buildX {
                b.showcmd(dir, "%s", strings.Join(cmdline, " "))
                if buildN {
-                       return nil
+                       return nil, nil
                }
        }
 
@@ -834,20 +860,7 @@ func (b *builder) run(dir string, desc string, cmdargs ...interface{}) error {
        cmd.Dir = dir
        // TODO: cmd.Env
        err := cmd.Run()
-       if buf.Len() > 0 {
-               out := buf.Bytes()
-               if out[len(out)-1] != '\n' {
-                       out = append(out, '\n')
-               }
-               if desc == "" {
-                       desc = b.fmtcmd(dir, "%s", strings.Join(cmdline, " "))
-               }
-               b.showOutput(dir, desc, string(out))
-               if err != nil {
-                       err = errPrintedOutput
-               }
-       }
-       return err
+       return buf.Bytes(), err
 }
 
 // mkdir makes the named directory.
@@ -980,6 +993,25 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
 
        outObj = append(outObj, "") // for importObj, at end of function
 
+       cgoCFLAGS := stringList(p.info.CgoCFLAGS)
+       cgoLDFLAGS := stringList(p.info.CgoLDFLAGS)
+       if pkgs := p.info.CgoPkgConfig; len(pkgs) > 0 {
+               out, err := b.runOut(p.Dir, p.ImportPath, "pkg-config", "--cflags", pkgs)
+               if err != nil {
+                       return nil, nil, err
+               }
+               if len(out) > 0 {
+                       cgoCFLAGS = append(cgoCFLAGS, strings.Fields(string(out))...)
+               }
+               out, err = b.runOut(p.Dir, p.ImportPath, "pkg-config", "--libs", pkgs)
+               if err != nil {
+                       return nil, nil, err
+               }
+               if len(out) > 0 {
+                       cgoLDFLAGS = append(cgoLDFLAGS, strings.Fields(string(out))...)
+               }
+       }
+
        // cgo
        // TODO: CGOPKGPATH, CGO_FLAGS?
        gofiles := []string{obj + "_cgo_gotypes.go"}
@@ -991,7 +1023,6 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
        }
        defunC := obj + "_cgo_defun.c"
        // TODO: make cgo not depend on $GOARCH?
-       // TODO: make cgo write to obj
        var runtimeFlag []string
        if p.Standard && p.ImportPath == "runtime/cgo" {
                runtimeFlag = []string{"-import_runtime_cgo=false"}
@@ -1012,7 +1043,7 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
        var linkobj []string
        for _, cfile := range cfiles {
                ofile := obj + cfile[:len(cfile)-1] + "o"
-               if err := b.gcc(p, ofile, p.info.CgoCFLAGS, obj+cfile); err != nil {
+               if err := b.gcc(p, ofile, cgoCFLAGS, obj+cfile); err != nil {
                        return nil, nil, err
                }
                linkobj = append(linkobj, ofile)
@@ -1022,14 +1053,14 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
        }
        for _, file := range gccfiles {
                ofile := obj + cgoRe.ReplaceAllString(file[:len(file)-1], "_") + "o"
-               if err := b.gcc(p, ofile, p.info.CgoCFLAGS, file); err != nil {
+               if err := b.gcc(p, ofile, cgoCFLAGS, file); err != nil {
                        return nil, nil, err
                }
                linkobj = append(linkobj, ofile)
                outObj = append(outObj, ofile)
        }
        dynobj := obj + "_cgo_.o"
-       if err := b.gccld(p, dynobj, p.info.CgoLDFLAGS, linkobj); err != nil {
+       if err := b.gccld(p, dynobj, cgoLDFLAGS, linkobj); err != nil {
                return nil, nil, err
        }