proc: support DW_AT_go_package_name (#1757)

Use the name specified by compile unit attribute DW_AT_go_package_name,
introduced in Go 1.13, to map package names to package paths, instead of
trying to deduce it from names of types.
Also use this mapping for resolving global variables and function
expressions.

_fixtures/internal/dir.io/dir.go

@@ -3,3 +3,9 @@ package dirio
 type SomeType struct {
 	X int
 }
+
+var A string = "something"
+
+func SomeFunction() {
+	println("hello world")
+}

_fixtures/pkgrenames.go

@@ -8,6 +8,7 @@ import (
 	pkg1 "go/ast"
 	pkg2 "net/http"
 
+	"github.com/go-delve/delve/_fixtures/internal/dir.io"
 	"github.com/go-delve/delve/_fixtures/internal/dir0/pkg"
 	"github.com/go-delve/delve/_fixtures/internal/dir0/renamedpackage"
 	dir1pkg "github.com/go-delve/delve/_fixtures/internal/dir1/pkg"
@@ -51,5 +52,5 @@ func main() {
 	m := t.Method(0)
 	fmt.Println(m.Type.In(0))
 	fmt.Println(m.Type.String())
-	fmt.Println(badexpr, req, amap, amap2, dir0someType, dir1someType, amap3, anarray, achan, aslice, afunc, astruct, astruct2, iface2iface, iface3, pkg.SomeVar, pkg.A, dir1pkg.A)
+	fmt.Println(badexpr, req, amap, amap2, dir0someType, dir1someType, amap3, anarray, achan, aslice, afunc, astruct, astruct2, iface2iface, iface3, pkg.SomeVar, pkg.A, dir1pkg.A, dirio.A, dirio.SomeFunction)
 }

pkg/dwarf/godwarf/type.go

@@ -26,6 +26,7 @@ const (
 	AttrGoElem          dwarf.Attr = 0x2902
 	AttrGoEmbeddedField dwarf.Attr = 0x2903
 	AttrGoRuntimeType   dwarf.Attr = 0x2904
+	AttrGoPackageName   dwarf.Attr = 0x2905
 )
 
 // Basic type encodings -- the value for AttrEncoding in a TagBaseType Entry.

pkg/proc/bininfo.go

@@ -61,8 +61,16 @@ type BinaryInfo struct {
 	closer         io.Closer
 	sepDebugCloser io.Closer
 
-	// Maps package names to package paths, needed to lookup types inside DWARF info
-	packageMap map[string]string
+	// PackageMap maps package names to package paths, needed to lookup types inside DWARF info.
+	// On Go1.12 this mapping is determined by using the last element of a package path, for example:
+	//   github.com/go-delve/delve
+	// will map to 'delve' because it ends in '/delve'.
+	// Starting with Go1.13 debug_info will contain a special attribute
+	// (godwarf.AttrGoPackageName) containing the canonical package name for
+	// each package.
+	// If multiple packages have the same name the map entry will have more
+	// than one item in the slice.
+	PackageMap map[string][]string
 
 	frameEntries frame.FrameDescriptionEntries
 
@@ -1253,7 +1261,7 @@ func (bi *BinaryInfo) registerTypeToPackageMap(entry *dwarf.Entry) {
 		return
 	}
 	name := path[slash+1:]
-	bi.packageMap[name] = path
+	bi.PackageMap[name] = []string{path}
 }
 
 func (bi *BinaryInfo) loadDebugInfoMaps(image *Image, debugLineBytes []byte, wg *sync.WaitGroup, cont func()) {
@@ -1267,8 +1275,8 @@ func (bi *BinaryInfo) loadDebugInfoMaps(image *Image, debugLineBytes []byte, wg
 	if bi.consts == nil {
 		bi.consts = make(map[dwarfRef]*constantType)
 	}
-	if bi.packageMap == nil {
-		bi.packageMap = make(map[string]string)
+	if bi.PackageMap == nil {
+		bi.PackageMap = make(map[string][]string)
 	}
 	if bi.inlinedCallLines == nil {
 		bi.inlinedCallLines = make(map[fileLine][]uint64)
@@ -1329,6 +1337,10 @@ func (bi *BinaryInfo) loadDebugInfoMaps(image *Image, debugLineBytes []byte, wg
 					cu.producer = cu.producer[:semicolon]
 				}
 			}
+			gopkg, _ := entry.Val(godwarf.AttrGoPackageName).(string)
+			if cu.isgo && gopkg != "" {
+				bi.PackageMap[gopkg] = append(bi.PackageMap[gopkg], escapePackagePath(strings.Replace(cu.name, "\\", "/", -1)))
+			}
 			bi.compileUnits = append(bi.compileUnits, cu)
 			if entry.Children {
 				bi.loadDebugInfoMapsCompileUnit(ctxt, image, reader, cu)
@@ -1370,6 +1382,8 @@ func (bi *BinaryInfo) loadDebugInfoMaps(image *Image, debugLineBytes []byte, wg
 
 // loadDebugInfoMapsCompileUnit loads entry from a single compile unit.
 func (bi *BinaryInfo) loadDebugInfoMapsCompileUnit(ctxt *loadDebugInfoMapsContext, image *Image, reader *reader.Reader, cu *compileUnit) {
+	hasAttrGoPkgName := goversion.ProducerAfterOrEqual(cu.producer, 1, 13)
+
 	for entry, err := reader.Next(); entry != nil; entry, err = reader.Next() {
 		if err != nil {
 			image.setLoadError("error reading debug_info: %v", err)
@@ -1391,7 +1405,7 @@ func (bi *BinaryInfo) loadDebugInfoMapsCompileUnit(ctxt *loadDebugInfoMapsContex
 					bi.types[name] = dwarfRef{image.index, entry.Offset}
 				}
 			}
-			if cu != nil && cu.isgo {
+			if cu != nil && cu.isgo && !hasAttrGoPkgName {
 				bi.registerTypeToPackageMap(entry)
 			}
 			image.registerRuntimeTypeToDIE(entry, ctxt.ardr)
@@ -1684,8 +1698,13 @@ func (bi *BinaryInfo) expandPackagesInType(expr ast.Expr) {
 	case *ast.SelectorExpr:
 		switch x := e.X.(type) {
 		case *ast.Ident:
-			if path, ok := bi.packageMap[x.Name]; ok {
-				x.Name = path
+			if len(bi.PackageMap[x.Name]) > 0 {
+				// There's no particular reason to expect the first entry to be the
+				// correct one if the package name is ambiguous, but trying all possible
+				// expansions of all types mentioned in the expression is complicated
+				// and, besides type assertions, users can always specify the type they
+				// want exactly, using a string.
+				x.Name = bi.PackageMap[x.Name][0]
 			}
 		default:
 			bi.expandPackagesInType(e.X)
@@ -1697,6 +1716,17 @@ func (bi *BinaryInfo) expandPackagesInType(expr ast.Expr) {
 	}
 }
 
+// escapePackagePath returns pkg with '.' replaced with '%2e' (in all
+// elements of the path except the first one) like Go does in variable and
+// type names.
+func escapePackagePath(pkg string) string {
+	slash := strings.Index(pkg, "/")
+	if slash < 0 {
+		slash = 0
+	}
+	return pkg[:slash] + strings.Replace(pkg[slash:], ".", "%2e", -1)
+}
+
 // Looks up symbol (either functions or global variables) at address addr.
 // Used by disassembly formatter.
 func (bi *BinaryInfo) symLookup(addr uint64) (string, uint64) {

pkg/proc/eval.go

@@ -379,7 +379,21 @@ func (scope *EvalScope) PackageVariables(cfg LoadConfig) ([]*Variable, error) {
 	return vars, nil
 }
 
-func (scope *EvalScope) findGlobal(name string) (*Variable, error) {
+func (scope *EvalScope) findGlobal(pkgName, varName string) (*Variable, error) {
+	for _, pkgPath := range scope.BinInfo.PackageMap[pkgName] {
+		v, err := scope.findGlobalInternal(pkgPath + "." + varName)
+		if err != nil || v != nil {
+			return v, err
+		}
+	}
+	v, err := scope.findGlobalInternal(pkgName + "." + varName)
+	if err != nil || v != nil {
+		return v, err
+	}
+	return nil, fmt.Errorf("could not find symbol value for %s.%s", pkgName, varName)
+}
+
+func (scope *EvalScope) findGlobalInternal(name string) (*Variable, error) {
 	for _, pkgvar := range scope.BinInfo.packageVars {
 		if pkgvar.name == name || strings.HasSuffix(pkgvar.name, "/"+name) {
 			reader := pkgvar.cu.image.dwarfReader
@@ -426,7 +440,7 @@ func (scope *EvalScope) findGlobal(name string) (*Variable, error) {
 			}
 		}
 	}
-	return nil, fmt.Errorf("could not find symbol value for %s", name)
+	return nil, nil
 }
 
 // image returns the image containing the current function.
@@ -608,7 +622,7 @@ func (scope *EvalScope) evalAST(t ast.Expr) (*Variable, error) {
 				return scope.g.variable.clone(), nil
 			} else if maybePkg.Name == "runtime" && node.Sel.Name == "frameoff" {
 				return newConstant(constant.MakeInt64(scope.frameOffset), scope.Mem), nil
-			} else if v, err := scope.findGlobal(maybePkg.Name + "." + node.Sel.Name); err == nil {
+			} else if v, err := scope.findGlobal(maybePkg.Name, node.Sel.Name); err == nil {
 				return v, nil
 			}
 		}
@@ -616,7 +630,7 @@ func (scope *EvalScope) evalAST(t ast.Expr) (*Variable, error) {
 		if maybePkg, ok := node.X.(*ast.BasicLit); ok && maybePkg.Kind == token.STRING {
 			pkgpath, err := strconv.Unquote(maybePkg.Value)
 			if err == nil {
-				if v, err := scope.findGlobal(pkgpath + "." + node.Sel.Name); err == nil {
+				if v, err := scope.findGlobal(pkgpath, node.Sel.Name); err == nil {
 					return v, nil
 				}
 			}
@@ -1013,7 +1027,7 @@ func (scope *EvalScope) evalIdent(node *ast.Ident) (*Variable, error) {
 
 	// if it's not a local variable then it could be a package variable w/o explicit package name
 	if scope.Fn != nil {
-		if v, err := scope.findGlobal(scope.Fn.PackageName() + "." + node.Name); err == nil {
+		if v, err := scope.findGlobal(scope.Fn.PackageName(), node.Name); err == nil {
 			v.Name = node.Name
 			return v, nil
 		}

pkg/proc/moduledata.go

@@ -15,7 +15,7 @@ type moduleData struct {
 func loadModuleData(bi *BinaryInfo, mem MemoryReadWriter) ([]moduleData, error) {
 	scope := globalScope(bi, bi.Images[0], mem)
 	var md *Variable
-	md, err := scope.findGlobal("runtime.firstmoduledata")
+	md, err := scope.findGlobal("runtime", "firstmoduledata")
 	if err != nil {
 		return nil, err
 	}
@@ -131,7 +131,7 @@ func resolveNameOff(bi *BinaryInfo, mds []moduleData, typeAddr uintptr, off uint
 
 func reflectOffsMapAccess(bi *BinaryInfo, off uintptr, mem MemoryReadWriter) (*Variable, error) {
 	scope := globalScope(bi, bi.Images[0], mem)
-	reflectOffs, err := scope.findGlobal("runtime.reflectOffs")
+	reflectOffs, err := scope.findGlobal("runtime", "reflectOffs")
 	if err != nil {
 		return nil, err
 	}

service/debugger/locations.go

@@ -216,7 +216,7 @@ func stripReceiverDecoration(in string) string {
 	return in[2 : len(in)-1]
 }
 
-func (spec *FuncLocationSpec) Match(sym proc.Function) bool {
+func (spec *FuncLocationSpec) Match(sym proc.Function, packageMap map[string][]string) bool {
 	if spec.BaseName != sym.BaseName() {
 		return false
 	}
@@ -231,17 +231,26 @@ func (spec *FuncLocationSpec) Match(sym proc.Function) bool {
 				return false
 			}
 		} else {
-			if !partialPathMatch(spec.PackageName, sym.PackageName()) {
+			if !packageMatch(spec.PackageName, sym.PackageName(), packageMap) {
 				return false
 			}
 		}
 	}
-	if spec.PackageOrReceiverName != "" && !partialPathMatch(spec.PackageOrReceiverName, sym.PackageName()) && spec.PackageOrReceiverName != recv {
+	if spec.PackageOrReceiverName != "" && !packageMatch(spec.PackageOrReceiverName, sym.PackageName(), packageMap) && spec.PackageOrReceiverName != recv {
 		return false
 	}
 	return true
 }
 
+func packageMatch(specPkg, symPkg string, packageMap map[string][]string) bool {
+	for _, pkg := range packageMap[specPkg] {
+		if partialPackageMatch(pkg, symPkg) {
+			return true
+		}
+	}
+	return partialPackageMatch(specPkg, symPkg)
+}
+
 func (loc *RegexLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr string, includeNonExecutableLines bool) ([]api.Location, error) {
 	funcs := d.target.BinInfo().Functions
 	matches, err := regexFilterFuncs(loc.FuncRegex, funcs)
@@ -304,6 +313,10 @@ func partialPathMatch(expr, path string) bool {
 		expr = strings.ToLower(filepath.ToSlash(expr))
 		path = strings.ToLower(filepath.ToSlash(path))
 	}
+	return partialPackageMatch(expr, path)
+}
+
+func partialPackageMatch(expr, path string) bool {
 	if len(expr) < len(path)-1 {
 		return strings.HasSuffix(path, expr) && (path[len(path)-len(expr)-1] == '/')
 	} else {
@@ -347,7 +360,7 @@ func (loc *NormalLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr s
 	var candidateFuncs []string
 	if loc.FuncBase != nil {
 		for _, f := range d.target.BinInfo().Functions {
-			if !loc.FuncBase.Match(f) {
+			if !loc.FuncBase.Match(f, d.target.BinInfo().PackageMap) {
 				continue
 			}
 			if loc.Base == f.Name {

service/test/integration2_test.go

@@ -725,6 +725,13 @@ func TestClientServer_FindLocations(t *testing.T) {
 		}
 		c.ClearBreakpoint(bp.ID)
 	})
+
+	if goversion.VersionAfterOrEqual(runtime.Version(), 1, 13) {
+		withTestClient2("pkgrenames", t, func(c service.Client) {
+			someFuncLoc := findLocationHelper(t, c, "github.com/go-delve/delve/_fixtures/internal/dir%2eio.SomeFunction:0", false, 1, 0)[0]
+			findLocationHelper(t, c, "dirio.SomeFunction:0", false, 1, someFuncLoc)
+		})
+	}
 }
 
 func TestClientServer_FindLocationsAddr(t *testing.T) {

service/test/variables_test.go

@@ -971,6 +971,23 @@ func TestIssue426(t *testing.T) {
 	})
 }
 
+func testPackageRenamesHelper(t *testing.T, p proc.Process, testcases []varTest) {
+	for _, tc := range testcases {
+		variable, err := evalVariable(p, tc.name, pnormalLoadConfig)
+		if tc.err == nil {
+			assertNoError(err, t, fmt.Sprintf("EvalExpression(%s) returned an error", tc.name))
+			assertVariable(t, variable, tc)
+		} else {
+			if err == nil {
+				t.Fatalf("Expected error %s, got no error (%s)", tc.err.Error(), tc.name)
+			}
+			if tc.err.Error() != err.Error() {
+				t.Fatalf("Unexpected error. Expected %s got %s", tc.err.Error(), err.Error())
+			}
+		}
+	}
+}
+
 func TestPackageRenames(t *testing.T) {
 	// Tests that the concrete type of an interface variable is resolved
 	// correctly in a few edge cases, in particular:
@@ -999,41 +1016,43 @@ func TestPackageRenames(t *testing.T) {
 		{"aslice", true, `interface {}([]github.com/go-delve/delve/_fixtures/internal/dir0/pkg.SomeType) [{X: 3},{X: 4}]`, "", "interface {}", nil},
 		{"afunc", true, `interface {}(func(github.com/go-delve/delve/_fixtures/internal/dir0/pkg.SomeType, github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType)) main.main.func1`, "", "interface {}", nil},
 		{"astruct", true, `interface {}(*struct { A github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType; B github.com/go-delve/delve/_fixtures/internal/dir0/pkg.SomeType }) *{A: github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, B: github.com/go-delve/delve/_fixtures/internal/dir0/pkg.SomeType {X: 3}}`, "", "interface {}", nil},
-		{"astruct2", true, `interface {}(*struct { github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{SomeType: github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`, "", "interface {}", nil},
 		{"iface2iface", true, `interface {}(*interface { AMethod(int) int; AnotherMethod(int) int }) **github.com/go-delve/delve/_fixtures/internal/dir0/pkg.SomeType {X: 4}`, "", "interface {}", nil},
 
 		{`"dir0/pkg".A`, false, "0", "", "int", nil},
 		{`"dir1/pkg".A`, false, "1", "", "int", nil},
 	}
 
-	ver, _ := goversion.Parse(runtime.Version())
-	if ver.Major > 0 && !ver.AfterOrEqual(goversion.GoVersion{1, 7, -1, 0, 0, ""}) {
-		// Not supported on 1.6 or earlier
+	testcases1_8 := []varTest{
+		// before 1.9 embedded struct fields have fieldname == type
+		{"astruct2", true, `interface {}(*struct { github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType: github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`, "", "interface {}", nil},
+	}
+
+	testcases1_9 := []varTest{
+		{"astruct2", true, `interface {}(*struct { github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{SomeType: github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`, "", "interface {}", nil},
+	}
+
+	testcases1_13 := []varTest{
+		// needs DW_AT_go_package_name attribute added to Go1.13
+		{`dirio.A`, false, `"something"`, "", "string", nil},
+	}
+
+	if !goversion.VersionAfterOrEqual(runtime.Version(), 1, 7) {
 		return
 	}
 
 	protest.AllowRecording(t)
 	withTestProcess("pkgrenames", t, func(p proc.Process, fixture protest.Fixture) {
 		assertNoError(proc.Continue(p), t, "Continue() returned an error")
-		for _, tc := range testcases {
-			if ver.Major > 0 && !ver.AfterOrEqual(goversion.GoVersion{1, 9, -1, 0, 0, ""}) {
-				// before 1.9 embedded struct field have fieldname == type
-				if tc.name == "astruct2" {
-					tc.value = `interface {}(*struct { github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType: github.com/go-delve/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`
-				}
-			}
-			variable, err := evalVariable(p, tc.name, pnormalLoadConfig)
-			if tc.err == nil {
-				assertNoError(err, t, fmt.Sprintf("EvalExpression(%s) returned an error", tc.name))
-				assertVariable(t, variable, tc)
-			} else {
-				if err == nil {
-					t.Fatalf("Expected error %s, got no error (%s)", tc.err.Error(), tc.name)
-				}
-				if tc.err.Error() != err.Error() {
-					t.Fatalf("Unexpected error. Expected %s got %s", tc.err.Error(), err.Error())
-				}
-			}
+		testPackageRenamesHelper(t, p, testcases)
+
+		if goversion.VersionAfterOrEqual(runtime.Version(), 1, 9) {
+			testPackageRenamesHelper(t, p, testcases1_9)
+		} else {
+			testPackageRenamesHelper(t, p, testcases1_8)
+		}
+
+		if goversion.VersionAfterOrEqual(runtime.Version(), 1, 13) {
+			testPackageRenamesHelper(t, p, testcases1_13)
 		}
 	})
 }
@@ -1049,7 +1068,7 @@ func TestConstants(t *testing.T) {
 		{"bitZero", true, "1", "", "main.BitFieldType", nil},
 		{"bitOne", true, "2", "", "main.BitFieldType", nil},
 		{"constTwo", true, "2", "", "main.ConstType", nil},
-		{"pkg.SomeConst", true, "2", "", "int", nil},
+		{"pkg.SomeConst", false, "2", "", "int", nil},
 	}
 	ver, _ := goversion.Parse(runtime.Version())
 	if ver.Major > 0 && !ver.AfterOrEqual(goversion.GoVersion{1, 10, -1, 0, 0, ""}) {