Improve array evaluation support

* First of a few commits to allow for evaluating arrays of arbitrary
  types
* Adds support for 32 bit integer arrays

_fixtures/testvariables.go

@@ -24,10 +24,11 @@ func foobar(baz string) {
 		neg = -1
 		i8  = int8(1)
 		f32 = float32(1.2)
+		i32 = [2]int32{1, 2}
 	)
 
 	barfoo()
-	fmt.Println(a1, a2, a3, a4, a5, a6, a7, baz, neg, i8, f32)
+	fmt.Println(a1, a2, a3, a4, a5, a6, a7, baz, neg, i8, f32, i32)
 }
 
 func main() {

proctl/variables.go

@@ -559,27 +559,24 @@ func (thread *ThreadContext) readIntSlice(addr uintptr) (string, error) {
 }
 
 func (thread *ThreadContext) readIntArray(addr uintptr, t *dwarf.ArrayType) (string, error) {
-	var (
-		number  uint64
-		members = make([]uint64, 0, t.ByteSize)
-	)
-
 	val, err := thread.readMemory(addr, uintptr(t.ByteSize))
 	if err != nil {
 		return "", err
 	}
 
-	buf := bytes.NewBuffer(val)
-	for {
-		err := binary.Read(buf, binary.LittleEndian, &number)
-		if err != nil {
-			break
-		}
-
-		members = append(members, number)
+	switch t.Type.Size() {
+	case 4:
+		members := *(*[]uint32)(unsafe.Pointer(&val))
+		lptr := (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(&members)) + ptrsize))
+		*lptr = int(t.Count)
+		return fmt.Sprintf("[%d]int32 %d", t.Count, members), nil
+	case 8:
+		members := *(*[]uint64)(unsafe.Pointer(&val))
+		lptr := (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(&members)) + ptrsize))
+		*lptr = int(t.Count)
+		return fmt.Sprintf("[%d]int %d", t.Count, members), nil
 	}
-
-	return fmt.Sprintf("[%d]int %d", t.ByteSize/int64(ptrsize), members), nil
+	return "", fmt.Errorf("Could not read array")
 }
 
 func (thread *ThreadContext) readInt(addr uintptr, size int64) (string, error) {

proctl/variables_test.go

@@ -30,10 +30,11 @@ func TestVariableEvaluation(t *testing.T) {
 		{"i8", "1", "int8"},
 		{"f32", "1.2", "float32"},
 		{"a6.Baz", "8", "int"},
+		{"i32", "[2]int32 [1 2]", "[2]int32"},
 	}
 
 	withTestProcess(executablePath, t, func(p *DebuggedProcess) {
-		pc, _, _ := p.GoSymTable.LineToPC(fp, 29)
+		pc, _, _ := p.GoSymTable.LineToPC(fp, 30)
 
 		_, err := p.Break(uintptr(pc))
 		assertNoError(err, t, "Break() returned an error")