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-rw-r--r--misc/cgo/test/issue8428.go48
-rw-r--r--src/cmd/cgo/gcc.go65
-rw-r--r--src/pkg/debug/dwarf/type.go52
3 files changed, 108 insertions, 57 deletions
diff --git a/misc/cgo/test/issue8428.go b/misc/cgo/test/issue8428.go
new file mode 100644
index 000000000..f5b0ee497
--- /dev/null
+++ b/misc/cgo/test/issue8428.go
@@ -0,0 +1,48 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cgotest
+
+// Issue 8428. Cgo inconsistently translated zero size arrays.
+
+/*
+struct issue8428one {
+ char b;
+ char rest[];
+};
+
+struct issue8428two {
+ void *p;
+ char b;
+ char rest[0];
+};
+
+struct issue8428three {
+ char w[1][2][3][0];
+ char x[2][3][0][1];
+ char y[3][0][1][2];
+ char z[0][1][2][3];
+};
+*/
+import "C"
+
+import "unsafe"
+
+var _ = C.struct_issue8428one{
+ b: C.char(0),
+ rest: [0]C.char{},
+}
+
+var _ = C.struct_issue8428two{
+ p: unsafe.Pointer(nil),
+ b: C.char(0),
+ rest: [0]C.char{},
+}
+
+var _ = C.struct_issue8428three{
+ w: [1][2][3][0]C.char{},
+ x: [2][3][0][1]C.char{},
+ y: [3][0][1][2]C.char{},
+ z: [0][1][2][3]C.char{},
+}
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 26def654d..482b35197 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -1075,12 +1075,6 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
return t
}
- // clang won't generate DW_AT_byte_size for pointer types,
- // so we have to fix it here.
- if dt, ok := base(dtype).(*dwarf.PtrType); ok && dt.ByteSize == -1 {
- dt.ByteSize = c.ptrSize
- }
-
t := new(Type)
t.Size = dtype.Size() // note: wrong for array of pointers, corrected below
t.Align = -1
@@ -1104,12 +1098,20 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
t.Go = c.Opaque(t.Size)
break
}
+ count := dt.Count
+ if count == -1 {
+ // Indicates flexible array member, which Go doesn't support.
+ // Translate to zero-length array instead.
+ count = 0
+ }
sub := c.Type(dt.Type, pos)
t.Align = sub.Align
t.Go = &ast.ArrayType{
- Len: c.intExpr(dt.Count),
+ Len: c.intExpr(count),
Elt: sub.Go,
}
+ // Recalculate t.Size now that we know sub.Size.
+ t.Size = count * sub.Size
t.C.Set("__typeof__(%s[%d])", sub.C, dt.Count)
case *dwarf.BoolType:
@@ -1210,6 +1212,11 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
}
case *dwarf.PtrType:
+ // Clang doesn't emit DW_AT_byte_size for pointer types.
+ if t.Size != c.ptrSize && t.Size != -1 {
+ fatalf("%s: unexpected: %d-byte pointer type - %s", lineno(pos), t.Size, dtype)
+ }
+ t.Size = c.ptrSize
t.Align = c.ptrSize
if _, ok := base(dt.Type).(*dwarf.VoidType); ok {
@@ -1381,34 +1388,24 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
}
}
- if t.Size <= 0 {
- // Clang does not record the size of a pointer in its DWARF entry,
- // so if dtype is an array, the call to dtype.Size at the top of the function
- // computed the size as the array length * 0 = 0.
- // The type switch called Type (this function) recursively on the pointer
- // entry, and the code near the top of the function updated the size to
- // be correct, so calling dtype.Size again will produce the correct value.
- t.Size = dtype.Size()
- if t.Size < 0 {
- // Unsized types are [0]byte, unless they're typedefs of other types
- // or structs with tags.
- // if so, use the name we've already defined.
- t.Size = 0
- switch dt := dtype.(type) {
- case *dwarf.TypedefType:
- // ok
- case *dwarf.StructType:
- if dt.StructName != "" {
- break
- }
- t.Go = c.Opaque(0)
- default:
- t.Go = c.Opaque(0)
- }
- if t.C.Empty() {
- t.C.Set("void")
+ if t.Size < 0 {
+ // Unsized types are [0]byte, unless they're typedefs of other types
+ // or structs with tags.
+ // if so, use the name we've already defined.
+ t.Size = 0
+ switch dt := dtype.(type) {
+ case *dwarf.TypedefType:
+ // ok
+ case *dwarf.StructType:
+ if dt.StructName != "" {
+ break
}
- return t
+ t.Go = c.Opaque(0)
+ default:
+ t.Go = c.Opaque(0)
+ }
+ if t.C.Empty() {
+ t.C.Set("void")
}
}
diff --git a/src/pkg/debug/dwarf/type.go b/src/pkg/debug/dwarf/type.go
index b64333ecc..fa40b2bef 100644
--- a/src/pkg/debug/dwarf/type.go
+++ b/src/pkg/debug/dwarf/type.go
@@ -118,7 +118,12 @@ func (t *ArrayType) String() string {
return "[" + strconv.FormatInt(t.Count, 10) + "]" + t.Type.String()
}
-func (t *ArrayType) Size() int64 { return t.Count * t.Type.Size() }
+func (t *ArrayType) Size() int64 {
+ if t.Count == -1 {
+ return 0
+ }
+ return t.Count * t.Type.Size()
+}
// A VoidType represents the C void type.
type VoidType struct {
@@ -369,7 +374,7 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
t.StrideBitSize, _ = e.Val(AttrStrideSize).(int64)
// Accumulate dimensions,
- ndim := 0
+ var dims []int64
for kid := next(); kid != nil; kid = next() {
// TODO(rsc): Can also be TagEnumerationType
// but haven't seen that in the wild yet.
@@ -381,26 +386,24 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
count, ok = kid.Val(AttrUpperBound).(int64)
if ok {
count++ // Length is one more than upper bound.
- } else {
+ } else if len(dims) == 0 {
count = -1 // As in x[].
}
}
- if ndim == 0 {
- t.Count = count
- } else {
- // Multidimensional array.
- // Create new array type underneath this one.
- t.Type = &ArrayType{Type: t.Type, Count: count}
- }
- ndim++
+ dims = append(dims, count)
case TagEnumerationType:
err = DecodeError{name, kid.Offset, "cannot handle enumeration type as array bound"}
goto Error
}
}
- if ndim == 0 {
+ if len(dims) == 0 {
// LLVM generates this for x[].
- t.Count = -1
+ dims = []int64{-1}
+ }
+
+ t.Count = dims[0]
+ for i := len(dims) - 1; i >= 1; i-- {
+ t.Type = &ArrayType{Type: t.Type, Count: dims[i]}
}
case TagBaseType:
@@ -476,7 +479,7 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
t.StructName, _ = e.Val(AttrName).(string)
t.Incomplete = e.Val(AttrDeclaration) != nil
t.Field = make([]*StructField, 0, 8)
- var lastFieldType Type
+ var lastFieldType *Type
var lastFieldBitOffset int64
for kid := next(); kid != nil; kid = next() {
if kid.Tag == TagMember {
@@ -518,7 +521,7 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
// (DWARF writes out 0-length arrays as if they were 1-length arrays.)
zeroArray(lastFieldType)
}
- lastFieldType = f.Type
+ lastFieldType = &f.Type
lastFieldBitOffset = bito
}
}
@@ -667,13 +670,16 @@ Error:
return nil, err
}
-func zeroArray(t Type) {
- for {
- at, ok := t.(*ArrayType)
- if !ok {
- break
- }
- at.Count = 0
- t = at.Type
+func zeroArray(t *Type) {
+ if t == nil {
+ return
+ }
+ at, ok := (*t).(*ArrayType)
+ if !ok || at.Type.Size() == 0 {
+ return
}
+ // Make a copy to avoid invalidating typeCache.
+ tt := *at
+ tt.Count = 0
+ *t = &tt
}
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