import debug/gosym from usr/austin/sym

R=austin
DELTA=958  (956 added, 0 deleted, 2 changed)
OCL=34180
CL=34212

src/pkg/debug/binary/binary.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// This package implements translation between
+// unsigned integer values and byte sequences.
 package binary
 
 import (
@@ -12,7 +14,7 @@ import (
 )
 
 // A ByteOrder specifies how to convert byte sequences into
-// 16-, 32-, or 64-bit integers.
+// 16-, 32-, or 64-bit unsigned integers.
 type ByteOrder interface {
 	Uint16(b []byte) uint16;
 	Uint32(b []byte) uint32;

src/pkg/debug/elf/file.go

@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Package elf implements access to ELF object files.
 package elf
 
 import (
 	"debug/binary";
-"fmt";
+	"fmt";
 	"io";
 	"os";
 )
@@ -66,6 +67,13 @@ type Section struct {
 	sr *io.SectionReader;
 }
 
+// Data reads and returns the contents of the ELF section.
+func (s *Section) Data() ([]byte, os.Error) {
+	dat := make([]byte, s.sr.Size());
+	n, err := s.sr.ReadAt(dat, 0);
+	return dat[0:n], err;
+}
+
 // Open returns a new ReadSeeker reading the ELF section.
 func (s *Section) Open() io.ReadSeeker {
 	return io.NewSectionReader(s.sr, 0, 1<<63 - 1);

src/pkg/debug/gosym/pclinetest.h

+// Empty include file to generate z symbols
+
+
+
+
+
+// EOF

src/pkg/debug/gosym/pclntab.go

+// 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.
+
+/*
+ * Line tables
+ */
+
+package gosym
+
+import (
+	"debug/binary";
+	"io";
+)
+
+type LineTable struct {
+	Data []byte;
+	PC uint64;
+	Line int;
+}
+
+// TODO(rsc): Need to pull in quantum from architecture definition.
+const quantum = 1;
+
+func (t *LineTable) parse(targetPC uint64, targetLine int) (b []byte, pc uint64, line int) {
+	// The PC/line table can be thought of as a sequence of
+	//  <pc update>* <line update>
+	// batches.  Each update batch results in a (pc, line) pair,
+	// where line applies to every PC from pc up to but not
+	// including the pc of the next pair.
+	//
+	// Here we process each update individually, which simplifies
+	// the code, but makes the corner cases more confusing.
+	b, pc, line = t.Data, t.PC, t.Line;
+	for pc <= targetPC && line != targetLine && len(b) > 0 {
+		code := b[0];
+		b = b[1:len(b)];
+		switch {
+		case code == 0:
+			if len(b) < 4 {
+				b = b[0:0];
+				break;
+			}
+			val := binary.BigEndian.Uint32(b);
+			b = b[4:len(b)];
+			line += int(val);
+		case code <= 64:
+			line += int(code);
+		case code <= 128:
+			line -= int(code - 64);
+		default:
+			pc += quantum*uint64(code - 128);
+			continue;
+		}
+		pc += quantum;
+	}
+	return b, pc, line;
+}
+
+func (t *LineTable) slice(pc uint64) *LineTable {
+	data, pc, line := t.parse(pc, -1);
+	return &LineTable{data, pc, line};
+}
+
+func (t *LineTable) PCToLine(pc uint64) int {
+	b, pc, line := t.parse(pc, -1);
+	return line;
+}
+
+func (t *LineTable) LineToPC(line int, maxpc uint64) uint64 {
+	b, pc, line1 := t.parse(maxpc, line);
+	if line1 != line {
+		return 0;
+	}
+	// Subtract quantum from PC to account for post-line increment
+	return pc - quantum;
+}
+
+// NewLineTable returns a new PC/line table
+// corresponding to the encoded data.
+// Text must be the start address of the
+// corresponding text segment.
+func NewLineTable(data []byte, text uint64) *LineTable {
+	return &LineTable{data, text, 0};
+}

src/pkg/debug/gosym/pclntab_test.go

+// 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 gosym
+
+import (
+	"debug/elf";
+	"exec";
+	"io";
+	"os";
+	"testing";
+	"syscall";
+)
+
+func dotest() bool {
+	// For now, only works on ELF platforms.
+	return syscall.OS == "linux" && os.Getenv("GOARCH") == "amd64"
+}
+
+func getTable(t *testing.T) *Table {
+	f, tab := crack(os.Args[0], t);
+	f.Close();
+	return tab;
+}
+
+func crack(file string, t *testing.T) (*elf.File, *Table) {
+	// Open self
+	f, err := elf.Open(file);
+	if err != nil {
+		t.Fatal(err);
+	}
+	return parse(file, f, t);
+}
+
+func parse(file string, f *elf.File, t *testing.T) (*elf.File, *Table) {
+	symdat, err := f.Section(".gosymtab").Data();
+	if err != nil {
+		f.Close();
+		t.Fatalf("reading %s gosymtab: %v", file, err);
+	}
+	pclndat, err := f.Section(".gopclntab").Data();
+	if err != nil {
+		f.Close();
+		t.Fatalf("reading %s gopclntab: %v", file, err);
+	}
+
+	pcln := NewLineTable(pclndat, f.Section(".text").Addr);
+	tab, err := NewTable(symdat, pcln);
+	if err != nil {
+		f.Close();
+		t.Fatalf("parsing %s gosymtab: %v", file, err);
+	}
+
+	return f, tab;
+}
+
+var goarch = os.Getenv("O")
+
+func TestLineFromAline(t *testing.T) {
+	if !dotest() {
+		return;
+	}
+
+	tab := getTable(t);
+
+	// Find the sym package
+	pkg := tab.LookupFunc("gosym.TestLineFromAline").Obj;
+	if pkg == nil {
+		t.Fatalf("nil pkg");
+	}
+
+	// Walk every absolute line and ensure that we hit every
+	// source line monotonically
+	lastline := make(map[string] int);
+	final := -1;
+	for i := 0; i < 10000; i++ {
+		path, line := pkg.lineFromAline(i);
+		// Check for end of object
+		if path == "" {
+			if final == -1 {
+				final = i - 1;
+			}
+			continue;
+		} else if final != -1 {
+			t.Fatalf("reached end of package at absolute line %d, but absolute line %d mapped to %s:%d", final, i, path, line);
+		}
+		// It's okay to see files multiple times (e.g., sys.a)
+		if line == 1 {
+			lastline[path] = 1;
+			continue;
+		}
+		// Check that the is the next line in path
+		ll, ok := lastline[path];
+		if !ok {
+			t.Errorf("file %s starts on line %d", path, line);
+		} else if line != ll + 1 {
+			t.Errorf("expected next line of file %s to be %d, got %d", path, ll + 1, line);
+		}
+		lastline[path] = line;
+	}
+	if final == -1 {
+		t.Errorf("never reached end of object");
+	}
+}
+
+func TestLineAline(t *testing.T) {
+	if !dotest() {
+		return;
+	}
+
+	tab := getTable(t);
+
+	for _, o := range tab.Files {
+		// A source file can appear multiple times in a
+		// object.  alineFromLine will always return alines in
+		// the first file, so track which lines we've seen.
+		found := make(map[string] int);
+		for i := 0; i < 1000; i++ {
+			path, line := o.lineFromAline(i);
+			if path == "" {
+				break;
+			}
+
+			// cgo files are full of 'Z' symbols, which we don't handle
+			if len(path) > 4 && path[len(path)-4:len(path)] == ".cgo" {
+				continue;
+			}
+
+			if minline, ok := found[path]; path != "" && ok {
+				if minline >= line {
+					// We've already covered this file
+					continue;
+				}
+			}
+			found[path] = line;
+
+			a, err := o.alineFromLine(path, line);
+			if err != nil {
+				t.Errorf("absolute line %d in object %s maps to %s:%d, but mapping that back gives error %s", i, o.Paths[0].Name, path, line, err);
+			} else if a != i {
+				t.Errorf("absolute line %d in object %s maps to %s:%d, which maps back to absolute line %d\n", i, o.Paths[0].Name, path, line, a);
+			}
+		}
+	}
+}
+
+// gotest: if [ "$(uname)-$(uname -m)" = Linux-x86_64 ]; then
+// gotest:    mkdir -p _test && $AS pclinetest.s && $LD -E main -l -o _test/pclinetest pclinetest.$O
+// gotest: fi
+func TestPCLine(t *testing.T) {
+	if !dotest() {
+		return;
+	}
+
+	f, tab := crack("_test/pclinetest", t);
+	text := f.Section(".text");
+	textdat, err := text.Data();
+	if err != nil {
+		t.Fatalf("reading .text: %v", err);
+	}
+
+	// Test PCToLine
+	sym := tab.LookupFunc("linefrompc");
+	wantLine := 0;
+	for pc := sym.Entry; pc < sym.End; pc++ {
+		file, line, fn := tab.PCToLine(pc);
+		off := pc - text.Addr;	// TODO(rsc): should not need off; bug in 8g
+		wantLine += int(textdat[off]);
+		if fn == nil {
+			t.Errorf("failed to get line of PC %#x", pc);
+		} else if len(file) < 12 || file[len(file)-12:len(file)] != "pclinetest.s" || line != wantLine || fn != sym {
+			t.Errorf("expected %s:%d (%s) at PC %#x, got %s:%d (%s)", "pclinetest.s", wantLine, sym.Name, pc, file, line, fn.Name);
+		}
+	}
+
+	// Test LineToPC
+	sym = tab.LookupFunc("pcfromline");
+	lookupline := -1;
+	wantLine = 0;
+	off := uint64(0);	// TODO(rsc): should not need off; bug in 8g
+	for pc := sym.Value; pc < sym.End; pc += 2 + uint64(textdat[off]) {
+		file, line, fn := tab.PCToLine(pc);
+		off = pc-text.Addr;
+		wantLine += int(textdat[off]);
+		if line != wantLine {
+			t.Errorf("expected line %d at PC %#x in pcfromline, got %d", wantLine, pc, line);
+			off = pc+1-text.Addr;
+			continue;
+		}
+		if lookupline == -1 {
+			lookupline = line;
+		}
+		for ; lookupline <= line; lookupline++ {
+			pc2, fn2, err := tab.LineToPC(file, lookupline);
+			if lookupline != line {
+				// Should be nothing on this line
+				if err == nil {
+					t.Errorf("expected no PC at line %d, got %#x (%s)", lookupline, pc2, fn2.Name);
+				}
+			} else if err != nil {
+				t.Errorf("failed to get PC of line %d: %s", lookupline, err);
+			} else if pc != pc2 {
+				t.Errorf("expected PC %#x (%s) at line %d, got PC %#x (%s)", pc, fn.Name, line, pc2, fn2.Name);
+			}
+		}
+		off = pc+1-text.Addr;
+	}
+}

src/pkg/io/io.go

@@ -321,3 +321,7 @@ func (s *SectionReader) ReadAt(p []byte, off int64) (n int, err os.Error) {
 	return s.r.ReadAt(p, off);
 }
 
+// Size returns the size of the section in bytes.
+func (s *SectionReader) Size() int64 {
+	return s.limit - s.base
+}