cmd/internal/goobj: accept int64 in readInt

The counter part, writeInt in cmd/internal/obj, writes int64s.
So the reader side should also read int64s. This may cause a
larger range of values being accepted, some of which should
not be that large. This is probably ok: for example, for
size/index/length, the very large value (due to corruption)
may be well past the end and causes other errors. And we did
not do much bound check anyway.

One exmaple where this matters is ARM32's object file. For one
type of relocation it encodes the instruction into Reloc.Add
field (which itself may be problematic and worth fix) and the
instruction encoding overflows int32, causing ARM32 object
file being rejected by goobj (and so objdump and nm) before.

Unskip ARM32 object file tests in goobj, nm, and objdump.

Updates #19811.

Change-Id: Ia46c2b68df5f1c5204d6509ceab6416ad6372315
Reviewed-on: https://go-review.googlesource.com/69010
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/internal/goobj/goobj_test.go

@@ -32,14 +32,6 @@ func TestMain(m *testing.M) {
 		return
 	}
 
-	if runtime.GOARCH == "arm" {
-		switch runtime.GOOS {
-		case "darwin", "android", "nacl":
-		default:
-			return // skip tests due to #19811
-		}
-	}
-
 	if err := buildGoobj(); err != nil {
 		fmt.Println(err)
 		os.RemoveAll(buildDir)

src/cmd/internal/goobj/read.go

@@ -25,7 +25,7 @@ type Sym struct {
 	SymID                // symbol identifier (name and version)
 	Kind  objabi.SymKind // kind of symbol
 	DupOK bool           // are duplicate definitions okay?
-	Size  int            // size of corresponding data
+	Size  int64          // size of corresponding data
 	Type  SymID          // symbol for Go type information
 	Data  Data           // memory image of symbol
 	Reloc []Reloc        // relocations to apply to Data
@@ -43,7 +43,7 @@ type SymID struct {
 	// declarations in C) have a non-zero version distinguishing
 	// a symbol in one file from a symbol of the same name
 	// in another file
-	Version int
+	Version int64
 }
 
 func (s SymID) String() string {
@@ -67,10 +67,10 @@ type Reloc struct {
 	// The bytes at [Offset, Offset+Size) within the containing Sym
 	// should be updated to refer to the address Add bytes after the start
 	// of the symbol Sym.
-	Offset int
-	Size   int
+	Offset int64
+	Size   int64
 	Sym    SymID
-	Add    int
+	Add    int64
 
 	// The Type records the form of address expected in the bytes
 	// described by the previous fields: absolute, PC-relative, and so on.
@@ -85,16 +85,16 @@ type Var struct {
 	// identifies a variable in a function stack frame.
 	// Using fewer of these - in particular, using only Name - does not.
 	Name   string // Name of variable.
-	Kind   int    // TODO(rsc): Define meaning.
-	Offset int    // Frame offset. TODO(rsc): Define meaning.
+	Kind   int64  // TODO(rsc): Define meaning.
+	Offset int64  // Frame offset. TODO(rsc): Define meaning.
 
 	Type SymID // Go type for variable.
 }
 
 // Func contains additional per-symbol information specific to functions.
 type Func struct {
-	Args     int        // size in bytes of argument frame: inputs and outputs
-	Frame    int        // size in bytes of local variable frame
+	Args     int64      // size in bytes of argument frame: inputs and outputs
+	Frame    int64      // size in bytes of local variable frame
 	Leaf     bool       // function omits save of link register (ARM)
 	NoSplit  bool       // function omits stack split prologue
 	Var      []Var      // detail about local variables
@@ -119,9 +119,9 @@ type FuncData struct {
 // An InlinedCall is a node in an InlTree.
 // See cmd/internal/obj.InlTree for details.
 type InlinedCall struct {
-	Parent int
+	Parent int64
 	File   string
-	Line   int
+	Line   int64
 	Func   SymID
 }
 
@@ -131,7 +131,7 @@ type Package struct {
 	Imports    []string        // packages imported by this package
 	SymRefs    []SymID         // list of symbol names and versions referred to by this pack
 	Syms       []*Sym          // symbols defined by this package
-	MaxVersion int             // maximum Version in any SymID in Syms
+	MaxVersion int64           // maximum Version in any SymID in Syms
 	Arch       string          // architecture
 	Native     []*NativeReader // native object data (e.g. ELF)
 }
@@ -255,7 +255,7 @@ func (r *objReader) readFull(b []byte) error {
 }
 
 // readInt reads a zigzag varint from the input file.
-func (r *objReader) readInt() int {
+func (r *objReader) readInt() int64 {
 	var u uint64
 
 	for shift := uint(0); ; shift += 7 {
@@ -270,12 +270,7 @@ func (r *objReader) readInt() int {
 		}
 	}
 
-	v := int64(u>>1) ^ (int64(u) << 63 >> 63)
-	if int64(int(v)) != v {
-		r.error(errCorruptObject) // TODO
-		return 0
-	}
-	return int(v)
+	return int64(u>>1) ^ (int64(u) << 63 >> 63)
 }
 
 // readString reads a length-delimited string from the input file.
@@ -313,8 +308,8 @@ func (r *objReader) readRef() {
 // readData reads a data reference from the input file.
 func (r *objReader) readData() Data {
 	n := r.readInt()
-	d := Data{Offset: r.dataOffset, Size: int64(n)}
-	r.dataOffset += int64(n)
+	d := Data{Offset: r.dataOffset, Size: n}
+	r.dataOffset += n
 	return d
 }
 
@@ -530,7 +525,7 @@ func (r *objReader) parseObject(prefix []byte) error {
 	r.readInt() // n files - ignore
 
 	r.dataOffset = r.offset
-	r.skip(int64(dataLength))
+	r.skip(dataLength)
 
 	// Symbols.
 	for {
@@ -615,7 +610,7 @@ func (r *objReader) parseObject(prefix []byte) error {
 }
 
 func (r *Reloc) String(insnOffset uint64) string {
-	delta := r.Offset - int(insnOffset)
+	delta := r.Offset - int64(insnOffset)
 	s := fmt.Sprintf("[%d:%d]%s", delta, delta+r.Size, r.Type)
 	if r.Sym.Name != "" {
 		if r.Add != 0 {

src/cmd/nm/nm_cgo_test.go

@@ -36,12 +36,5 @@ func TestExternalLinkerCgoExec(t *testing.T) {
 }
 
 func TestCgoLib(t *testing.T) {
-	if runtime.GOARCH == "arm" {
-		switch runtime.GOOS {
-		case "darwin", "android", "nacl":
-		default:
-			t.Skip("skip test due to #19811")
-		}
-	}
 	testGoLib(t, true)
 }

src/cmd/objdump/objdump_test.go

@@ -198,8 +198,6 @@ func TestDisasmExtld(t *testing.T) {
 
 func TestDisasmGoobj(t *testing.T) {
 	switch runtime.GOARCH {
-	case "arm":
-		t.Skipf("skipping on %s, issue 19811", runtime.GOARCH)
 	case "mips", "mipsle", "mips64", "mips64le":
 		t.Skipf("skipping on %s, issue 12559", runtime.GOARCH)
 	case "s390x":