basic DWARF reading.

R=r
DELTA=949  (949 added, 0 deleted, 0 changed)
OCL=34676
CL=34678

1 files changed, 63 insertions, 0 deletions

diff --git a/src/pkg/debug/dwarf/unit.go b/src/pkg/debug/dwarf/unit.go
new file mode 100644
index 0000000000..040151f39d
--- /dev/null
+++ b/src/pkg/debug/dwarf/unit.go
@@ -0,0 +1,63 @@
+// Copyright 2009 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 dwarf
+
+import (
+	"os";
+	"strconv";
+)
+
+// DWARF debug info is split into a sequence of compilation units.
+// Each unit has its own abbreviation table and address size.
+
+type unit struct {
+	base Offset;	// byte offset of header within the aggregate info
+	off Offset;	// byte offset of data within the aggregate info
+	data []byte;
+	atable abbrevTable;
+	addrsize int;
+}
+
+func (d *Data) parseUnits() ([]unit, os.Error) {
+	// Count units.
+	nunit := 0;
+	b := makeBuf(d, "info", 0, d.info, 0);
+	for len(b.data) > 0 {
+		b.skip(int(b.uint32()));
+		nunit++;
+	}
+	if b.err != nil {
+		return nil, b.err;
+	}
+
+	// Again, this time writing them down.
+	b = makeBuf(d, "info", 0, d.info, 0);
+	units := make([]unit, nunit);
+	for i := range units {
+		u := &units[i];
+		u.base = b.off;
+		n := b.uint32();
+		if vers := b.uint16(); vers != 2 {
+			b.error("unsupported DWARF version " + strconv.Itoa(int(vers)));
+			break;
+		}
+		atable, err := d.parseAbbrev(b.uint32());
+		if err != nil {
+			if b.err == nil {
+				b.err = err;
+			}
+			break;
+		}
+		u.atable = atable;
+		u.addrsize = int(b.uint8());
+		u.off = b.off;
+		u.data = b.bytes(int(n - (2+4+1)));
+	}
+	if b.err != nil {
+		return nil, b.err;
+	}
+	return units, nil;
+}
+