1 files changed, 140 insertions, 0 deletions
diff --git a/src/debug/dwarf/open.go b/src/debug/dwarf/open.go
new file mode 100644
index 0000000..0901341
--- /dev/null
+++ b/src/debug/dwarf/open.go
@@ -0,0 +1,140 @@
+// 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 provides access to DWARF debugging information loaded from
+executable files, as defined in the DWARF 2.0 Standard at
+http://dwarfstd.org/doc/dwarf-2.0.0.pdf.
+
+# Security
+
+This package is not designed to be hardened against adversarial inputs, and is
+outside the scope of https://go.dev/security/policy. In particular, only basic
+validation is done when parsing object files. As such, care should be taken when
+parsing untrusted inputs, as parsing malformed files may consume significant
+resources, or cause panics.
+*/
+package dwarf
+
+import (
+	"encoding/binary"
+	"errors"
+)
+
+// Data represents the DWARF debugging information
+// loaded from an executable file (for example, an ELF or Mach-O executable).
+type Data struct {
+	// raw data
+	abbrev   []byte
+	aranges  []byte
+	frame    []byte
+	info     []byte
+	line     []byte
+	pubnames []byte
+	ranges   []byte
+	str      []byte
+
+	// New sections added in DWARF 5.
+	addr       []byte
+	lineStr    []byte
+	strOffsets []byte
+	rngLists   []byte
+
+	// parsed data
+	abbrevCache map[uint64]abbrevTable
+	bigEndian   bool
+	order       binary.ByteOrder
+	typeCache   map[Offset]Type
+	typeSigs    map[uint64]*typeUnit
+	unit        []unit
+}
+
+var errSegmentSelector = errors.New("non-zero segment_selector size not supported")
+
+// New returns a new [Data] object initialized from the given parameters.
+// Rather than calling this function directly, clients should typically use
+// the DWARF method of the File type of the appropriate package [debug/elf],
+// [debug/macho], or [debug/pe].
+//
+// The []byte arguments are the data from the corresponding debug section
+// in the object file; for example, for an ELF object, abbrev is the contents of
+// the ".debug_abbrev" section.
+func New(abbrev, aranges, frame, info, line, pubnames, ranges, str []byte) (*Data, error) {
+	d := &Data{
+		abbrev:      abbrev,
+		aranges:     aranges,
+		frame:       frame,
+		info:        info,
+		line:        line,
+		pubnames:    pubnames,
+		ranges:      ranges,
+		str:         str,
+		abbrevCache: make(map[uint64]abbrevTable),
+		typeCache:   make(map[Offset]Type),
+		typeSigs:    make(map[uint64]*typeUnit),
+	}
+
+	// Sniff .debug_info to figure out byte order.
+	// 32-bit DWARF: 4 byte length, 2 byte version.
+	// 64-bit DWARf: 4 bytes of 0xff, 8 byte length, 2 byte version.
+	if len(d.info) < 6 {
+		return nil, DecodeError{"info", Offset(len(d.info)), "too short"}
+	}
+	offset := 4
+	if d.info[0] == 0xff && d.info[1] == 0xff && d.info[2] == 0xff && d.info[3] == 0xff {
+		if len(d.info) < 14 {
+			return nil, DecodeError{"info", Offset(len(d.info)), "too short"}
+		}
+		offset = 12
+	}
+	// Fetch the version, a tiny 16-bit number (1, 2, 3, 4, 5).
+	x, y := d.info[offset], d.info[offset+1]
+	switch {
+	case x == 0 && y == 0:
+		return nil, DecodeError{"info", 4, "unsupported version 0"}
+	case x == 0:
+		d.bigEndian = true
+		d.order = binary.BigEndian
+	case y == 0:
+		d.bigEndian = false
+		d.order = binary.LittleEndian
+	default:
+		return nil, DecodeError{"info", 4, "cannot determine byte order"}
+	}
+
+	u, err := d.parseUnits()
+	if err != nil {
+		return nil, err
+	}
+	d.unit = u
+	return d, nil
+}
+
+// AddTypes will add one .debug_types section to the DWARF data. A
+// typical object with DWARF version 4 debug info will have multiple
+// .debug_types sections. The name is used for error reporting only,
+// and serves to distinguish one .debug_types section from another.
+func (d *Data) AddTypes(name string, types []byte) error {
+	return d.parseTypes(name, types)
+}
+
+// AddSection adds another DWARF section by name. The name should be a
+// DWARF section name such as ".debug_addr", ".debug_str_offsets", and
+// so forth. This approach is used for new DWARF sections added in
+// DWARF 5 and later.
+func (d *Data) AddSection(name string, contents []byte) error {
+	var err error
+	switch name {
+	case ".debug_addr":
+		d.addr = contents
+	case ".debug_line_str":
+		d.lineStr = contents
+	case ".debug_str_offsets":
+		d.strOffsets = contents
+	case ".debug_rnglists":
+		d.rngLists = contents
+	}
+	// Just ignore names that we don't yet support.
+	return err
+}