1 files changed, 379 insertions, 0 deletions
diff --git a/src/cmd/pprof/pprof.go b/src/cmd/pprof/pprof.go
new file mode 100644
index 0000000..11f91cb
--- /dev/null
+++ b/src/cmd/pprof/pprof.go
@@ -0,0 +1,379 @@
+// 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.
+
+// pprof is a tool for visualization of profile.data. It is based on
+// the upstream version at github.com/google/pprof, with minor
+// modifications specific to the Go distribution. Please consider
+// upstreaming any modifications to these packages.
+
+package main
+
+import (
+	"crypto/tls"
+	"debug/dwarf"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"cmd/internal/objfile"
+
+	"github.com/google/pprof/driver"
+	"github.com/google/pprof/profile"
+)
+
+func main() {
+	options := &driver.Options{
+		Fetch: new(fetcher),
+		Obj:   new(objTool),
+		UI:    newUI(),
+	}
+	if err := driver.PProf(options); err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(2)
+	}
+}
+
+type fetcher struct {
+}
+
+func (f *fetcher) Fetch(src string, duration, timeout time.Duration) (*profile.Profile, string, error) {
+	sourceURL, timeout := adjustURL(src, duration, timeout)
+	if sourceURL == "" {
+		// Could not recognize URL, let regular pprof attempt to fetch the profile (eg. from a file)
+		return nil, "", nil
+	}
+	fmt.Fprintln(os.Stderr, "Fetching profile over HTTP from", sourceURL)
+	if duration > 0 {
+		fmt.Fprintf(os.Stderr, "Please wait... (%v)\n", duration)
+	}
+	p, err := getProfile(sourceURL, timeout)
+	return p, sourceURL, err
+}
+
+func getProfile(source string, timeout time.Duration) (*profile.Profile, error) {
+	url, err := url.Parse(source)
+	if err != nil {
+		return nil, err
+	}
+
+	var tlsConfig *tls.Config
+	if url.Scheme == "https+insecure" {
+		tlsConfig = &tls.Config{
+			InsecureSkipVerify: true,
+		}
+		url.Scheme = "https"
+		source = url.String()
+	}
+
+	client := &http.Client{
+		Transport: &http.Transport{
+			ResponseHeaderTimeout: timeout + 5*time.Second,
+			Proxy:                 http.ProxyFromEnvironment,
+			TLSClientConfig:       tlsConfig,
+		},
+	}
+	resp, err := client.Get(source)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		defer resp.Body.Close()
+		return nil, statusCodeError(resp)
+	}
+	return profile.Parse(resp.Body)
+}
+
+func statusCodeError(resp *http.Response) error {
+	if resp.Header.Get("X-Go-Pprof") != "" && strings.Contains(resp.Header.Get("Content-Type"), "text/plain") {
+		// error is from pprof endpoint
+		if body, err := io.ReadAll(resp.Body); err == nil {
+			return fmt.Errorf("server response: %s - %s", resp.Status, body)
+		}
+	}
+	return fmt.Errorf("server response: %s", resp.Status)
+}
+
+// cpuProfileHandler is the Go pprof CPU profile handler URL.
+const cpuProfileHandler = "/debug/pprof/profile"
+
+// adjustURL applies the duration/timeout values and Go specific defaults
+func adjustURL(source string, duration, timeout time.Duration) (string, time.Duration) {
+	u, err := url.Parse(source)
+	if err != nil || (u.Host == "" && u.Scheme != "" && u.Scheme != "file") {
+		// Try adding http:// to catch sources of the form hostname:port/path.
+		// url.Parse treats "hostname" as the scheme.
+		u, err = url.Parse("http://" + source)
+	}
+	if err != nil || u.Host == "" {
+		return "", 0
+	}
+
+	if u.Path == "" || u.Path == "/" {
+		u.Path = cpuProfileHandler
+	}
+
+	// Apply duration/timeout overrides to URL.
+	values := u.Query()
+	if duration > 0 {
+		values.Set("seconds", fmt.Sprint(int(duration.Seconds())))
+	} else {
+		if urlSeconds := values.Get("seconds"); urlSeconds != "" {
+			if us, err := strconv.ParseInt(urlSeconds, 10, 32); err == nil {
+				duration = time.Duration(us) * time.Second
+			}
+		}
+	}
+	if timeout <= 0 {
+		if duration > 0 {
+			timeout = duration + duration/2
+		} else {
+			timeout = 60 * time.Second
+		}
+	}
+	u.RawQuery = values.Encode()
+	return u.String(), timeout
+}
+
+// objTool implements driver.ObjTool using Go libraries
+// (instead of invoking GNU binutils).
+type objTool struct {
+	mu          sync.Mutex
+	disasmCache map[string]*objfile.Disasm
+}
+
+func (*objTool) Open(name string, start, limit, offset uint64) (driver.ObjFile, error) {
+	of, err := objfile.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	f := &file{
+		name: name,
+		file: of,
+	}
+	if start != 0 {
+		if load, err := of.LoadAddress(); err == nil {
+			f.offset = start - load
+		}
+	}
+	return f, nil
+}
+
+func (*objTool) Demangle(names []string) (map[string]string, error) {
+	// No C++, nothing to demangle.
+	return make(map[string]string), nil
+}
+
+func (t *objTool) Disasm(file string, start, end uint64, intelSyntax bool) ([]driver.Inst, error) {
+	if intelSyntax {
+		return nil, fmt.Errorf("printing assembly in Intel syntax is not supported")
+	}
+	d, err := t.cachedDisasm(file)
+	if err != nil {
+		return nil, err
+	}
+	var asm []driver.Inst
+	d.Decode(start, end, nil, false, func(pc, size uint64, file string, line int, text string) {
+		asm = append(asm, driver.Inst{Addr: pc, File: file, Line: line, Text: text})
+	})
+	return asm, nil
+}
+
+func (t *objTool) cachedDisasm(file string) (*objfile.Disasm, error) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.disasmCache == nil {
+		t.disasmCache = make(map[string]*objfile.Disasm)
+	}
+	d := t.disasmCache[file]
+	if d != nil {
+		return d, nil
+	}
+	f, err := objfile.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	d, err = f.Disasm()
+	f.Close()
+	if err != nil {
+		return nil, err
+	}
+	t.disasmCache[file] = d
+	return d, nil
+}
+
+func (*objTool) SetConfig(config string) {
+	// config is usually used to say what binaries to invoke.
+	// Ignore entirely.
+}
+
+// file implements driver.ObjFile using Go libraries
+// (instead of invoking GNU binutils).
+// A file represents a single executable being analyzed.
+type file struct {
+	name   string
+	offset uint64
+	sym    []objfile.Sym
+	file   *objfile.File
+	pcln   objfile.Liner
+
+	triedDwarf bool
+	dwarf      *dwarf.Data
+}
+
+func (f *file) Name() string {
+	return f.name
+}
+
+func (f *file) Base() uint64 {
+	// No support for shared libraries.
+	return 0
+}
+
+func (f *file) BuildID() string {
+	// No support for build ID.
+	return ""
+}
+
+func (f *file) SourceLine(addr uint64) ([]driver.Frame, error) {
+	if f.pcln == nil {
+		pcln, err := f.file.PCLineTable()
+		if err != nil {
+			return nil, err
+		}
+		f.pcln = pcln
+	}
+	addr -= f.offset
+	file, line, fn := f.pcln.PCToLine(addr)
+	if fn != nil {
+		frame := []driver.Frame{
+			{
+				Func: fn.Name,
+				File: file,
+				Line: line,
+			},
+		}
+		return frame, nil
+	}
+
+	frames := f.dwarfSourceLine(addr)
+	if frames != nil {
+		return frames, nil
+	}
+
+	return nil, fmt.Errorf("no line information for PC=%#x", addr)
+}
+
+// dwarfSourceLine tries to get file/line information using DWARF.
+// This is for C functions that appear in the profile.
+// Returns nil if there is no information available.
+func (f *file) dwarfSourceLine(addr uint64) []driver.Frame {
+	if f.dwarf == nil && !f.triedDwarf {
+		// Ignore any error--we don't care exactly why there
+		// is no DWARF info.
+		f.dwarf, _ = f.file.DWARF()
+		f.triedDwarf = true
+	}
+
+	if f.dwarf != nil {
+		r := f.dwarf.Reader()
+		unit, err := r.SeekPC(addr)
+		if err == nil {
+			if frames := f.dwarfSourceLineEntry(r, unit, addr); frames != nil {
+				return frames
+			}
+		}
+	}
+
+	return nil
+}
+
+// dwarfSourceLineEntry tries to get file/line information from a
+// DWARF compilation unit. Returns nil if it doesn't find anything.
+func (f *file) dwarfSourceLineEntry(r *dwarf.Reader, entry *dwarf.Entry, addr uint64) []driver.Frame {
+	lines, err := f.dwarf.LineReader(entry)
+	if err != nil {
+		return nil
+	}
+	var lentry dwarf.LineEntry
+	if err := lines.SeekPC(addr, &lentry); err != nil {
+		return nil
+	}
+
+	// Try to find the function name.
+	name := ""
+FindName:
+	for entry, err := r.Next(); entry != nil && err == nil; entry, err = r.Next() {
+		if entry.Tag == dwarf.TagSubprogram {
+			ranges, err := f.dwarf.Ranges(entry)
+			if err != nil {
+				return nil
+			}
+			for _, pcs := range ranges {
+				if pcs[0] <= addr && addr < pcs[1] {
+					var ok bool
+					// TODO: AT_linkage_name, AT_MIPS_linkage_name.
+					name, ok = entry.Val(dwarf.AttrName).(string)
+					if ok {
+						break FindName
+					}
+				}
+			}
+		}
+	}
+
+	// TODO: Report inlined functions.
+
+	frames := []driver.Frame{
+		{
+			Func: name,
+			File: lentry.File.Name,
+			Line: lentry.Line,
+		},
+	}
+
+	return frames
+}
+
+func (f *file) Symbols(r *regexp.Regexp, addr uint64) ([]*driver.Sym, error) {
+	if f.sym == nil {
+		sym, err := f.file.Symbols()
+		if err != nil {
+			return nil, err
+		}
+		f.sym = sym
+	}
+	var out []*driver.Sym
+	for _, s := range f.sym {
+		// Ignore a symbol with address 0 and size 0.
+		// An ELF STT_FILE symbol will look like that.
+		if s.Addr == 0 && s.Size == 0 {
+			continue
+		}
+		if (r == nil || r.MatchString(s.Name)) && (addr == 0 || s.Addr <= addr && addr < s.Addr+uint64(s.Size)) {
+			out = append(out, &driver.Sym{
+				Name:  []string{s.Name},
+				File:  f.name,
+				Start: s.Addr,
+				End:   s.Addr + uint64(s.Size) - 1,
+			})
+		}
+	}
+	return out, nil
+}
+
+func (f *file) Close() error {
+	f.file.Close()
+	return nil
+}
+
+// newUI will be set in readlineui.go in some platforms
+// for interactive readline functionality.
+var newUI = func() driver.UI { return nil }