Go 1.16 support branch (#2214)

* proc: misc test fixes for Go 1.16

* proc: fix cgo stacktraces in Go 1.16 with simplified C -> Go call path

* dwarf/line: make dwarf/line correct when '\\' are used

Our code depends heavily on paths being '/' separated because go always
produced '/' separated file paths. The call to filepath.Join will
normalize the paths, on windows, to always be '\\' separated, which
violated our assumptions.

This didn't use to be a problem because the codepath that calls
filepath.Join was never exercised by executable files produced by Go,
but Go 1.16 started producing debug_line sections that use the
directory table with https://go-review.googlesource.com/c/go/+/263017/.

Fix this to always use path.Join after making sure, on windows, to
always normalize paths to use '/' as a separator. Replace the use of
filepath.IsAbs with an operating system independent version.

* goversion: bump supported Go version

pkg/dwarf/line/line_parser.go

@@ -3,7 +3,7 @@ package line
 import (
 	"bytes"
 	"encoding/binary"
-	"path/filepath"
+	"path"
 	"strings"
 
 	"github.com/go-delve/delve/pkg/dwarf/util"
@@ -193,21 +193,37 @@ func readFileEntry(info *DebugLineInfo, buf *bytes.Buffer, exitOnEmptyPath bool)
 	}
 
 	if info.normalizeBackslash {
-		entry.Path = strings.Replace(entry.Path, "\\", "/", -1)
+		entry.Path = strings.ReplaceAll(entry.Path, "\\", "/")
 	}
 
 	entry.DirIdx, _ = util.DecodeULEB128(buf)
 	entry.LastModTime, _ = util.DecodeULEB128(buf)
 	entry.Length, _ = util.DecodeULEB128(buf)
-	if !filepath.IsAbs(entry.Path) {
+	if !pathIsAbs(entry.Path) {
 		if entry.DirIdx >= 0 && entry.DirIdx < uint64(len(info.IncludeDirs)) {
-			entry.Path = filepath.Join(info.IncludeDirs[entry.DirIdx], entry.Path)
+			entry.Path = path.Join(info.IncludeDirs[entry.DirIdx], entry.Path)
 		}
 	}
 
 	return entry
 }
 
+// pathIsAbs returns true if this is an absolute path.
+// We can not use path.IsAbs because it will not recognize windows paths as
+// absolute. We also can not use filepath.Abs because we want this
+// processing to be independent of the host operating system (we could be
+// reading an executable file produced on windows on a unix machine or vice
+// versa).
+func pathIsAbs(s string) bool {
+	if len(s) >= 1 && s[0] == '/' {
+		return true
+	}
+	if len(s) >= 2 && s[1] == ':' && (('a' <= s[0] && s[0] <= 'z') || ('A' <= s[0] && s[0] <= 'Z')) {
+		return true
+	}
+	return false
+}
+
 // parseFileEntries5 parses the file table for DWARF 5
 func parseFileEntries5(info *DebugLineInfo, buf *bytes.Buffer) {
 	fileEntryFormReader := readEntryFormat(buf, info.Logf)
@@ -217,13 +233,13 @@ func parseFileEntries5(info *DebugLineInfo, buf *bytes.Buffer) {
 		fileEntryFormReader.reset()
 		for fileEntryFormReader.next(buf) {
 			entry := new(FileEntry)
-			var path string
+			var p string
 			var diridx int = -1
 
 			switch fileEntryFormReader.contentType {
 			case _DW_LNCT_path:
 				if fileEntryFormReader.formCode != _DW_FORM_string {
-					path = fileEntryFormReader.str
+					p = fileEntryFormReader.str
 				} else {
 					//TODO(aarzilli): support debug_string, debug_line_str
 					info.Logf("unsupported string form %#x", fileEntryFormReader.formCode)
@@ -238,10 +254,14 @@ func parseFileEntries5(info *DebugLineInfo, buf *bytes.Buffer) {
 				// not implemented
 			}
 
-			if diridx >= 0 && !filepath.IsAbs(path) && diridx < len(info.IncludeDirs) {
-				path = filepath.Join(info.IncludeDirs[diridx], path)
+			if info.normalizeBackslash {
+				p = strings.ReplaceAll(p, "\\", "/")
 			}
-			entry.Path = path
+
+			if diridx >= 0 && !pathIsAbs(p) && diridx < len(info.IncludeDirs) {
+				p = path.Join(info.IncludeDirs[diridx], p)
+			}
+			entry.Path = p
 			info.FileNames = append(info.FileNames, entry)
 			info.Lookup[entry.Path] = entry
 		}

pkg/dwarf/line/line_parser_test.go

@@ -11,12 +11,14 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
 	"unsafe"
 
 	"github.com/go-delve/delve/pkg/dwarf/godwarf"
+	"github.com/go-delve/delve/pkg/goversion"
 )
 
 var userTestFile string
@@ -113,8 +115,10 @@ func testDebugLinePrologueParser(p string, t *testing.T) {
 			}
 		}
 
-		if len(dbl.IncludeDirs) != 1 {
-			t.Fatal("Include dirs not parsed correctly")
+		if !goversion.VersionAfterOrEqual(runtime.Version(), 1, 16) {
+			if len(dbl.IncludeDirs) != 1 {
+				t.Fatal("Include dirs not parsed correctly")
+			}
 		}
 
 		for _, ln := range dbl.Lookup {
@@ -127,6 +131,7 @@ func testDebugLinePrologueParser(p string, t *testing.T) {
 		}
 
 		for _, n := range dbl.FileNames {
+			t.Logf("file %s\n", n.Path)
 			if strings.Contains(n.Path, "/_fixtures/testnextprog.go") {
 				mainFileFound = true
 				break

pkg/goversion/compat.go

@@ -8,7 +8,7 @@ var (
 	MinSupportedVersionOfGoMajor = 1
 	MinSupportedVersionOfGoMinor = 13
 	MaxSupportedVersionOfGoMajor = 1
-	MaxSupportedVersionOfGoMinor = 15
+	MaxSupportedVersionOfGoMinor = 16
 	goTooOldErr                  = fmt.Errorf("Version of Go is too old for this version of Delve (minimum supported version %d.%d, suppress this error with --check-go-version=false)", MinSupportedVersionOfGoMajor, MinSupportedVersionOfGoMinor)
 	dlvTooOldErr                 = fmt.Errorf("Version of Delve is too old for this version of Go (maximum supported version %d.%d, suppress this error with --check-go-version=false)", MaxSupportedVersionOfGoMajor, MaxSupportedVersionOfGoMinor)
 )

pkg/proc/amd64_arch.go

@@ -161,7 +161,7 @@ func amd64SwitchStack(it *stackIterator, _ *op.DwarfRegisters) bool {
 		it.top = false
 		return true
 
-	case "runtime.cgocallback_gofunc":
+	case "runtime.cgocallback_gofunc", "runtime.cgocallback":
 		// For a detailed description of how this works read the long comment at
 		// the start of $GOROOT/src/runtime/cgocall.go and the source code of
 		// runtime.cgocallback_gofunc in $GOROOT/src/runtime/asm_amd64.s

pkg/proc/arm64_arch.go

@@ -139,7 +139,7 @@ const spAlign = 16
 func arm64SwitchStack(it *stackIterator, callFrameRegs *op.DwarfRegisters) bool {
 	if it.frame.Current.Fn != nil {
 		switch it.frame.Current.Fn.Name {
-		case "runtime.asmcgocall", "runtime.cgocallback_gofunc", "runtime.sigpanic":
+		case "runtime.asmcgocall", "runtime.cgocallback_gofunc", "runtime.sigpanic", "runtime.cgocallback":
 			//do nothing
 		case "runtime.goexit", "runtime.rt0_go", "runtime.mcall":
 			// Look for "top of stack" functions.
@@ -202,7 +202,7 @@ func arm64SwitchStack(it *stackIterator, callFrameRegs *op.DwarfRegisters) bool
 		callFrameRegs.Reg(callFrameRegs.SPRegNum).Uint64Val = uint64(int64(newsp))
 		return false
 
-	case "runtime.cgocallback_gofunc":
+	case "runtime.cgocallback_gofunc", "runtime.cgocallback":
 		// For a detailed description of how this works read the long comment at
 		// the start of $GOROOT/src/runtime/cgocall.go and the source code of
 		// runtime.cgocallback_gofunc in $GOROOT/src/runtime/asm_arm64.s

service/test/integration2_test.go

@@ -1709,7 +1709,7 @@ func TestAcceptMulticlient(t *testing.T) {
 			},
 		})
 		if err := server.Run(); err != nil {
-			t.Fatal(err)
+			panic(err)
 		}
 		<-disconnectChan
 		server.Stop()