.

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

@@ -74,9 +74,20 @@ type traceImport struct {
 	// XXX back link to *Package?
 
 	Pos	token.Position
+	PkgName string
 	PkgPath string
 }
 
+// ImportSpec returns string representation of import spec
+func (ti *traceImport) ImportSpec() string {
+	t := ti.PkgName
+	if t != "" {
+		t += " "
+	}
+	t += fmt.Sprintf("%q", ti.PkgPath)
+	return t
+}
+
 // Package represents tracing-related information about a package
 type Package struct {
 	Pkgi *loader.PackageInfo // original non-augmented package
@@ -186,6 +197,44 @@ func (p *Package) parseTraceEvent(srcfile *ast.File, pos token.Position, text st
 	return &traceEvent{Pkgt: p, FuncDecl: declf}, nil
 }
 
+// parseTraceImport parses trace import directive into traceImport
+// text is text argument after "//trace:import "
+func (p *Package) parseTraceImport(pos token.Position, text string) (*traceImport, error) {
+	// //trace:import "path/to/pkg"
+	// //traca:import name "path/to/pkg"
+
+	if len(text) == 0 {
+		return nil, fmt.Errorf("%v: empty trace-import spec", pos)
+	}
+
+	pkgname := ""
+	pkgqpath := text
+
+	if !(text[0] == '"' || text[0] == '\'') {
+		textv := strings.SplitN(text, " ", 2)
+		if len(textv) != 2 {
+			return nil, fmt.Errorf("%v: invalid trace-import spec %v", pos, text)
+		}
+		pkgname = textv[0]
+		pkgqpath = textv[1]
+	}
+
+	// Unqote pkgqpath as in regular import does
+	pkgpath, err := strconv.Unquote(pkgqpath)
+	if err != nil || pkgpath == "" || pkgpath[0] == '\'' {
+		return nil, fmt.Errorf("%v: invalid trace-import path %v", pos, pkgqpath)
+	}
+
+	// reject duplicate imports
+	for _, imported := range p.Importv {
+		if pkgpath == imported.PkgPath {
+			return nil, fmt.Errorf("%v: duplicate trace import of %v (previous at %v)", pos, pkgpath, imported.Pos)
+		}
+	}
+
+	return &traceImport{Pos: pos, PkgName: pkgname, PkgPath: pkgpath}, nil
+}
+
 // packageTrace returns tracing information about a package
 func packageTrace(prog *loader.Program, pkgi *loader.PackageInfo) (*Package, error) {
 	// prepare Package with typechecker ready to typecheck trace files
@@ -263,19 +312,13 @@ func packageTrace(prog *loader.Program, pkgi *loader.PackageInfo) (*Package, err
 					p.Eventv = append(p.Eventv, event)
 
 				case "//trace:import":
-					// Unqote arg as in regular import
-					importPath, err := strconv.Unquote(arg)
-					if err != nil || arg[0] == '\'' {
-						return nil, fmt.Errorf("%v: invalid trace-import path %v", pos, arg)
+					imported, err := p.parseTraceImport(pos, arg)
+					if err != nil {
+						return nil, err
 					}
 
-					// reject duplicate imports
-					for _, imported := range p.Importv {
-						if importPath == imported.PkgPath {
-							return nil, fmt.Errorf("%v: duplicate trace import of %v (previous at %v)", pos, importPath, imported.Pos)
-						}
-					}
-					p.Importv = append(p.Importv, &traceImport{Pos: pos, PkgPath: importPath})
+					// XXX needed here? - better append in parseTraceEvent
+					p.Importv = append(p.Importv, imported)
 
 				default:
 					return nil, fmt.Errorf("%v: unknown tracing directive %q", pos, directive)
@@ -322,11 +365,12 @@ func (te *traceEvent) Argv() string {
 // ArgvTyped returns argument list with types
 // types are qualified relative to original package
 func (te *traceEvent) ArgvTyped() string {
-	return te.ArgvTypedRelativeTo(te.Pkgt.tracePkg)
+	return te.ArgvTypedRelativeTo(te.Pkgt.tracePkg, nil)
 }
 
 // ArgvTypedRelativeTo returns argument list with types qualified relative to specified package
-func (te *traceEvent) ArgvTypedRelativeTo(pkg *types.Package) string {
+// importedAs specifies under which name a package was imported, if name was explicitly set
+func (te *traceEvent) ArgvTypedRelativeTo(pkg *types.Package, importedAs map[string/*pkgpath*/]string/*pkgname*/) string {
 	argv := []string{}
 
 	// default qualifier - relative to original package
@@ -336,6 +380,12 @@ func (te *traceEvent) ArgvTypedRelativeTo(pkg *types.Package) string {
 			return ""
 		}
 
+		// qualify as explicitly named
+		pkgname := importedAs[p.Path()]
+		if pkgname != "" {
+			return pkgname
+		}
+
 		// default qualification
 		return p.Name()
 	}
@@ -415,8 +465,9 @@ 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 {{.Pkgt.Pkgi.Pkg.Name}}_{{.Name}}_Attach {{.Pkgt.Pkgi.Pkg.Path}}.{{.Name}}_Attach
-func {{.Pkgt.Pkgi.Pkg.Name}}_{{.Name}}_Attach(*tracing.ProbeGroup, func({{.ArgvTypedRelativeTo .ImporterPkg}})) *tracing.Probe
+{{/* function to attach a probe to tracepoint imported via go:linkname */ -}}
+//go:linkname {{.ImportSpec.PkgName}}_{{.Name}}_Attach {{.ImportSpec.PkgPath}}.{{.Name}}_Attach
+func {{.ImportSpec.PkgName}}_{{.Name}}_Attach(*tracing.ProbeGroup, func({{.ArgvTypedRelativeTo .ImporterPkg .ImportedAs}})) *tracing.Probe
 `))
 
 // magic begins all files generated by gotrace
@@ -592,9 +643,14 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 		prologue.emit("\nimport (")
 		prologue.emit("\t%q", "lab.nexedi.com/kirr/neo/go/xcommon/tracing")
 		prologue.emit("\t%q", "unsafe")
-		// import of all packages needed for used types will go here in the end
+
+
+		// import of all packages needed for used types
 		needPkg := StrSet{}
 
+		// some packages are imported with explicit name
+		importedAs := map[string/*pkgpath*/]string/*pkgname*/{}
+
 		// code for trace:event definitions
 		text := &Buffer{}
 		for _, event := range tpkg.Eventv {
@@ -609,13 +665,20 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 
 		// code for trace:import imports
 		for _, timport := range tpkg.Importv {
-			text.emit("\n// traceimport: %q", timport.PkgPath)
+			text.emit("\n// traceimport: %s", timport.ImportSpec())
 
 			impProg, impPkgi, err := P.Import(timport.PkgPath)
 			if err != nil {
 				return fmt.Errorf("%v: error trace-importing %s: %v", timport.Pos, timport.PkgPath, err)
 			}
 
+			// set name of the package if it was not explicitly specified
+			if timport.PkgName == "" {
+				timport.PkgName = impPkgi.Pkg.Name()
+			} else {
+				importedAs[timport.PkgPath] = timport.PkgName
+			}
+
 			impPkg, err := packageTrace(impProg, impPkgi)
 			if err != nil {
 				return err // XXX err ctx
@@ -625,8 +688,10 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 				needPkg.Add(event.NeedPkgv()...)
 				importedEvent := struct{
 					*traceEvent
-					ImporterPkg *types.Package
-				} {event, pkgi.Pkg }
+					ImportSpec   *traceImport
+					ImporterPkg  *types.Package
+					ImportedAs   map[string]string
+				} {event, timport, pkgi.Pkg, importedAs}
 				err = traceEventImportTmpl.Execute(text, importedEvent)
 				if err != nil {
 					panic(err)	// XXX
@@ -644,7 +709,11 @@ func tracegen(pkgpath string, ctxt *build.Context, cwd string) error {
 		}
 
 		for _, needpkg := range needPkgv {
-			prologue.emit("\t%q", needpkg)
+			pkgname := importedAs[needpkg]
+			if pkgname != "" {
+				pkgname += " "
+			}
+			prologue.emit("\t%s%q", pkgname, needpkg)
 		}
 		prologue.emit(")")
 

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

@@ -2,7 +2,10 @@ package pkg2
 
 // trace-import another package
 // NOTE "a/pkg1" is not regularly imported
-//trace:import "a/pkg1"
+////trace:import "a/pkg1"
+
+// XXX temp
+//trace:import bbb "a/pkg1"
 
 // additional tracepoint which pkg2 defines
 //trace:event traceDoSomething(i, j int, q string)

go/xcommon/tracing/cmd/gotrace/testdata/src/c/pkg3/pkg3_test.go

@@ -2,8 +2,8 @@ package pkg3
 
 import "testing"
 
-// trace import that should be added only to tests
-//trace:import "a/pkg1"
+// trace import that should be added only to tests, and under specified package name
+//trace:import aaa1 "a/pkg1"
 
 func TestZzz(t *testing.T) {
 	if zzz() != 2 {