.

go/xcommon/tracing/cmd/gotrace/gotrace.go

@@ -416,8 +416,8 @@ func {{.Name}}_Attach(pg *tracing.ProbeGroup, probe func({{.ArgvTyped}})) *traci
 
 // traceEventImportTmpl is code template generated for importing one trace event
 var traceEventImportTmpl = template.Must(template.New("traceimport").Parse(`
-//go:linkname {{.Pkg.Name}}_{{.Name}}_Attach {{.Pkg.Path}}.{{.Name}}_Attach
-func {{.Pkg.Name}}_{{.Name}}_Attach(*tracing.ProbeGroup, func({{.ArgvTypedRelativeTo .ImporterPkg}})) *tracing.Probe
+//go:linkname {{.Pkg.Pkgi.Pkg.Name}}_{{.Name}}_Attach {{.Pkg.Pkgi.Pkg.Path}}.{{.Name}}_Attach
+func {{.Pkg.Pkgi.Pkg.Name}}_{{.Name}}_Attach(*tracing.ProbeGroup, func({{.ArgvTypedRelativeTo .ImporterPkg}})) *tracing.Probe
 `))
 
 // magic begins all files generated by gotrace
@@ -538,14 +538,25 @@ func findPackageNoZTrace(ctxt *build.Context, importPath, fromDir string, mode b
 }
 */
 
-// tracegen generates code according to tracing directives in a package @ pkgpath
-//
-// ctxt is build context for discovering packages
-// cwd is "current" directory for resolving local imports (e.g. packages like "./some/package")
-func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
-	// TODO test-only with .TestGoFiles  .XTestGoFiles
 
-	// filter-out ztrace* files when disovering packages
+type Program struct {
+	// list of loader.Programs in use
+	//
+	// We generally need to have several programs because a package can
+	// trace:import another package which is not otherwise imported by
+	// original program.
+	//
+	// Since go/loader does not support incrementally augmenting loaded
+	// program with more packages we work-around it with having several
+	// progs.
+	progv []*loader.Program
+
+	// config for loading programs
+	loaderConf *loader.Config
+}
+
+func NewProgram(ctxt *build.Context, cwd string) *Program {
+	// adjust build context to filter-out ztrace* files when disovering packages
 	//
 	// we don't load what should be generated by us for 2 reasons:
 	// - code generated could be wrong with older version of the
@@ -568,23 +579,54 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 		return okv, err
 	}
 
-	// XXX text
-	conf := loader.Config{
+	p := &Program{}
+	p.loaderConf = &loader.Config{
 		ParserMode: parser.ParseComments,
 		TypeCheckFuncBodies: func(path string) bool { return false },
 		Build: &ctxtNoZTrace,
 		Cwd: cwd,
-//		FindPackage: findPackageNoZTrace,
 	}
-	conf.Import(pkgpath)
 
-	// load package + all its imports
-	lprog, err := conf.Load()
+	return p
+}
+
+// Import imports a package and returns associated package info and program under which it was loaded
+func (p *Program) Import(pkgpath string) (prog *loader.Program, pkgi *loader.PackageInfo, err error) {
+	// let's see - maybe it is already there
+	for _, prog := range p.progv {
+		pkgi := prog.Package(pkgpath)
+		if pkgi != nil {
+			return prog, pkgi, nil
+		}
+	}
+
+	// not found - we have to load new program rooted at pkgpath
+	p.loaderConf.ImportPkgs = nil
+	p.loaderConf.Import(pkgpath)
+
+	prog, err = p.loaderConf.Load()
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
-	pkgi := lprog.InitialPackages()[0]
+	p.progv = append(p.progv, prog)
+	pkgi = prog.InitialPackages()[0]
+	return prog, pkgi, nil
+}
+
+// tracegen generates code according to tracing directives in a package @ pkgpath
+//
+// ctxt is build context for discovering packages
+// cwd is "current" directory for resolving local imports (e.g. packages like "./some/package")
+func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
+	// TODO test-only with .TestGoFiles  .XTestGoFiles
+
+	P := NewProgram(ctxt, cwd)
+
+	lprog, pkgi, err := P.Import(pkgpath)
+	if err != nil {
+		return err
+	}
 
 	// determine package directory
 	if len(pkgi.Files) == 0 {
@@ -638,13 +680,12 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 		for _, timport := range tpkg.Importv {
 			text.emit("\n// traceimport: %v", timport.PkgPath)
 
-			impPkgi := lprog.Package(timport.PkgPath)
-			if impPkgi == nil {
-				// TODO do not require vvv
-				return fmt.Errorf("%v: package %s must be also regularly imported", timport.Pos, timport.PkgPath)
+			impProg, impPkgi, err := P.Import(timport.PkgPath)
+			if err != nil {
+				return fmt.Errorf("%v: error trace-importing %s: %v", timport.Pos, timport.PkgPath, err)
 			}
 
-			impPkg, err := packageTrace(lprog, impPkgi)
+			impPkg, err := packageTrace(impProg, impPkgi)
 			if err != nil {
 				return err // XXX err ctx
 			}

go/xcommon/tracing/cmd/gotrace/testdata/src/b/pkg2/ztrace.go.ok

+// Code generated by lab.nexedi.com/kirr/go123/tracing/cmd/gotrace; DO NOT EDIT.
+
+package pkg2
+// code generated for tracepoints
+
+import (
+	"lab.nexedi.com/kirr/neo/go/xcommon/tracing"
+	"unsafe"
+
+	"a/pkg1"
+	"net/url"
+)
+
+// traceevent: traceDoSomething(i, j int, q string)	XXX better raw .Text (e.g. comments)
+
+type _t_traceDoSomething struct {
+	tracing.Probe
+	probefunc     func(i, j int, q string)
+}
+
+var _traceDoSomething *_t_traceDoSomething
+
+func traceDoSomething(i, j int, q string) {
+	if _traceDoSomething != nil {
+		_traceDoSomething_run(i, j, q)
+	}
+}
+
+func _traceDoSomething_run(i, j int, q string) {
+	for p := _traceDoSomething; p != nil; p = (*_t_traceDoSomething)(unsafe.Pointer(p.Next())) {
+		p.probefunc(i, j, q)
+	}
+}
+
+func traceDoSomething_Attach(pg *tracing.ProbeGroup, probe func(i, j int, q string)) *tracing.Probe {
+	p := _t_traceDoSomething{probefunc: probe}
+	tracing.AttachProbe(pg, (**tracing.Probe)(unsafe.Pointer(&_traceDoSomething)), &p.Probe)
+	return &p.Probe
+}
+
+// traceimport: a/pkg1
+
+//go:linkname pkg1_traceDoSomething_Attach a/pkg1.traceDoSomething_Attach
+func pkg1_traceDoSomething_Attach(*tracing.ProbeGroup, func(topic string)) *tracing.Probe
+
+//go:linkname pkg1_traceNewT_Attach a/pkg1.traceNewT_Attach
+func pkg1_traceNewT_Attach(*tracing.ProbeGroup, func(t *pkg1.T)) *tracing.Probe
+
+//go:linkname pkg1_traceNewTPre_Attach a/pkg1.traceNewTPre_Attach
+func pkg1_traceNewTPre_Attach(*tracing.ProbeGroup, func()) *tracing.Probe
+
+//go:linkname pkg1_traceURLParsed_Attach a/pkg1.traceURLParsed_Attach
+func pkg1_traceURLParsed_Attach(*tracing.ProbeGroup, func(u *url.URL)) *tracing.Probe

go/xcommon/tracing/cmd/gotrace/testdata/src/b/pkg2/ztrace.s.ok

+// Code generated by lab.nexedi.com/kirr/go123/tracing/cmd/gotrace; DO NOT EDIT.
+// empty .s so `go build` does not use -complete for go:linkname to work