cmd/vendor: update vendored github.com/google/pprof for Go 1.20 release

The Go 1.20 code freeze has recently started. This is a time to
update the vendored copy.

Done by
	cd GOROOT/src/cmd
	go get -d github.com/google/pprof@latest
	go mod tidy
	go mod vendor

For #36905.

Change-Id: Iaec604c66ea8f4b7638a31bdb77d6dd56966e38a
Reviewed-on: https://go-review.googlesource.com/c/go/+/452815
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

15 files changed, 797 insertions, 33 deletions

diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
index 237cc33233..a9cae92d1b 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
@@ -363,5 +363,6 @@ var usageMsgVars = "\n\n" +
 	"   PPROF_TOOLS        Search path for object-level tools\n" +
 	"   PPROF_BINARY_PATH  Search path for local binary files\n" +
 	"                      default: $HOME/pprof/binaries\n" +
-	"                      searches $name, $path, $buildid/$name, $path/$buildid\n" +
+	"                      searches $buildid/$name, $buildid/*, $path/$buildid,\n" +
+	"                      ${buildid:0:2}/${buildid:2}.debug, $name, $path\n" +
 	"   * On Windows, %USERPROFILE% is used instead of $HOME"
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
index 6a1e64c600..27681c540f 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
@@ -59,9 +59,8 @@ func PProf(eo *plugin.Options) error {
 	return interactive(p, o)
 }
 
+// generateRawReport is allowed to modify p.
 func generateRawReport(p *profile.Profile, cmd []string, cfg config, o *plugin.Options) (*command, *report.Report, error) {
-	p = p.Copy() // Prevent modification to the incoming profile.
-
 	// Identify units of numeric tags in profile.
 	numLabelUnits := identifyNumLabelUnits(p, o.UI)
 
@@ -110,6 +109,7 @@ func generateRawReport(p *profile.Profile, cmd []string, cfg config, o *plugin.O
 	return c, rpt, nil
 }
 
+// generateReport is allowed to modify p.
 func generateReport(p *profile.Profile, cmd []string, cfg config, o *plugin.Options) error {
 	c, rpt, err := generateRawReport(p, cmd, cfg, o)
 	if err != nil {
@@ -201,7 +201,6 @@ func applyCommandOverrides(cmd string, outputFormat int, cfg config) config {
 	case report.Proto, report.Raw, report.Callgrind:
 		trim = false
 		cfg.Granularity = "addresses"
-		cfg.NoInlines = false
 	}
 
 	if !trim {
@@ -365,3 +364,23 @@ func valueExtractor(ix int) sampleValueFunc {
 		return v[ix]
 	}
 }
+
+// profileCopier can be used to obtain a fresh copy of a profile.
+// It is useful since reporting code may mutate the profile handed to it.
+type profileCopier []byte
+
+func makeProfileCopier(src *profile.Profile) profileCopier {
+	// Pre-serialize the profile. We will deserialize every time a fresh copy is needed.
+	var buf bytes.Buffer
+	src.WriteUncompressed(&buf)
+	return profileCopier(buf.Bytes())
+}
+
+// newCopy returns a new copy of the profile.
+func (c profileCopier) newCopy() *profile.Profile {
+	p, err := profile.ParseUncompressed([]byte(c))
+	if err != nil {
+		panic(err)
+	}
+	return p
+}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
index 0b361651bc..5ddee33610 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
@@ -18,7 +18,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -167,7 +166,7 @@ func grabSourcesAndBases(sources, bases []profileSource, fetch plugin.Fetcher, o
 // a single profile. It fetches a chunk of profiles concurrently, with a maximum
 // chunk size to limit its memory usage.
 func chunkedGrab(sources []profileSource, fetch plugin.Fetcher, obj plugin.ObjTool, ui plugin.UI, tr http.RoundTripper) (*profile.Profile, plugin.MappingSources, bool, int, error) {
-	const chunkSize = 64
+	const chunkSize = 128
 
 	var p *profile.Profile
 	var msrc plugin.MappingSources
@@ -242,10 +241,22 @@ func concurrentGrab(sources []profileSource, fetch plugin.Fetcher, obj plugin.Ob
 
 func combineProfiles(profiles []*profile.Profile, msrcs []plugin.MappingSources) (*profile.Profile, plugin.MappingSources, error) {
 	// Merge profiles.
+	//
+	// The merge call below only treats exactly matching sample type lists as
+	// compatible and will fail otherwise. Make the profiles' sample types
+	// compatible for the merge, see CompatibilizeSampleTypes() doc for details.
+	if err := profile.CompatibilizeSampleTypes(profiles); err != nil {
+		return nil, nil, err
+	}
 	if err := measurement.ScaleProfiles(profiles); err != nil {
 		return nil, nil, err
 	}
 
+	// Avoid expensive work for the common case of a single profile/src.
+	if len(profiles) == 1 && len(msrcs) == 1 {
+		return profiles[0], msrcs[0], nil
+	}
+
 	p, err := profile.Merge(profiles)
 	if err != nil {
 		return nil, nil, err
@@ -410,6 +421,10 @@ mapping:
 					fileNames = append(fileNames, matches...)
 				}
 				fileNames = append(fileNames, filepath.Join(path, m.File, m.BuildID)) // perf path format
+				// Llvm buildid protocol: the first two characters of the build id
+				// are used as directory, and the remaining part is in the filename.
+				// e.g. `/ab/cdef0123456.debug`
+				fileNames = append(fileNames, filepath.Join(path, m.BuildID[:2], m.BuildID[2:]+".debug"))
 			}
 			if m.File != "" {
 				// Try both the basename and the full path, to support the same directory
@@ -507,7 +522,7 @@ func fetchURL(source string, timeout time.Duration, tr http.RoundTripper) (io.Re
 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 := ioutil.ReadAll(resp.Body); err == nil {
+		if body, err := io.ReadAll(resp.Body); err == nil {
 			return fmt.Errorf("server response: %s - %s", resp.Status, body)
 		}
 	}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.css b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.css
index 03755abc0e..e0de53c1e1 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.css
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.css
@@ -116,6 +116,7 @@ a {
   box-shadow: 0 1px 5px rgba(0,0,0,.3);
   font-size: 100%;
   text-transform: none;
+  white-space: nowrap;
 }
 .menu-item, .submenu {
   user-select: none;
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.js b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.js
index 4fe3caa442..5282c1b363 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.js
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/common.js
@@ -388,7 +388,12 @@ function initConfigManager() {
   }
 }
 
-function viewer(baseUrl, nodes) {
+// options if present can contain:
+//   hiliter: function(Number, Boolean): Boolean
+//     Overridable mechanism for highlighting/unhighlighting specified node.
+//   current: function() Map[Number,Boolean]
+//     Overridable mechanism for fetching set of currently selected nodes.
+function viewer(baseUrl, nodes, options) {
   'use strict';
 
   // Elements
@@ -403,6 +408,16 @@ function viewer(baseUrl, nodes) {
   let searchAlarm = null;
   let buttonsEnabled = true;
 
+  // Return current selection.
+  function getSelection() {
+    if (selected.size > 0) {
+      return selected;
+    } else if (options && options.current) {
+      return options.current();
+    }
+    return new Map();
+  }
+
   function handleDetails(e) {
     e.preventDefault();
     const detailsText = document.getElementById('detailsbox');
@@ -453,7 +468,7 @@ function viewer(baseUrl, nodes) {
     // drop currently selected items that do not match re.
     selected.forEach(function(v, n) {
       if (!match(nodes[n])) {
-        unselect(n, document.getElementById('node' + n));
+        unselect(n);
       }
     })
 
@@ -461,7 +476,7 @@ function viewer(baseUrl, nodes) {
     if (nodes) {
       for (let n = 0; n < nodes.length; n++) {
         if (!selected.has(n) && match(nodes[n])) {
-          select(n, document.getElementById('node' + n));
+          select(n);
         }
       }
     }
@@ -482,23 +497,19 @@ function viewer(baseUrl, nodes) {
     const n = nodeId(elem);
     if (n < 0) return;
     if (selected.has(n)) {
-      unselect(n, elem);
+      unselect(n);
     } else {
-      select(n, elem);
+      select(n);
     }
     updateButtons();
   }
 
-  function unselect(n, elem) {
-    if (elem == null) return;
-    selected.delete(n);
-    setBackground(elem, false);
+  function unselect(n) {
+    if (setNodeHighlight(n, false)) selected.delete(n);
   }
 
   function select(n, elem) {
-    if (elem == null) return;
-    selected.set(n, true);
-    setBackground(elem, true);
+    if (setNodeHighlight(n, true)) selected.set(n, true);
   }
 
   function nodeId(elem) {
@@ -511,11 +522,17 @@ function viewer(baseUrl, nodes) {
     return n;
   }
 
-  function setBackground(elem, set) {
+  // Change highlighting of node (returns true if node was found).
+  function setNodeHighlight(n, set) {
+    if (options && options.hiliter) return options.hiliter(n, set);
+
+    const elem = document.getElementById('node' + n);
+    if (!elem) return false;
+
     // Handle table row highlighting.
     if (elem.nodeName == 'TR') {
       elem.classList.toggle('hilite', set);
-      return;
+      return true;
     }
 
     // Handle svg element highlighting.
@@ -528,6 +545,8 @@ function viewer(baseUrl, nodes) {
         p.style.fill = origFill.get(p);
       }
     }
+
+    return true;
   }
 
   function findPolygon(elem) {
@@ -575,8 +594,8 @@ function viewer(baseUrl, nodes) {
       // The selection can be in one of two modes: regexp-based or
       // list-based.  Construct regular expression depending on mode.
       let re = regexpActive
-        ? search.value
-        : Array.from(selected.keys()).map(key => quotemeta(nodes[key])).join('|');
+          ? search.value
+          : Array.from(getSelection().keys()).map(key => quotemeta(nodes[key])).join('|');
 
       setHrefParams(elem, function (params) {
         if (re != '') {
@@ -639,7 +658,7 @@ function viewer(baseUrl, nodes) {
   }
 
   function updateButtons() {
-    const enable = (search.value != '' || selected.size != 0);
+    const enable = (search.value != '' || getSelection().size != 0);
     if (buttonsEnabled == enable) return;
     buttonsEnabled = enable;
     for (const id of ['focus', 'ignore', 'hide', 'show', 'show-from']) {
@@ -663,8 +682,8 @@ function viewer(baseUrl, nodes) {
     toptable.addEventListener('touchstart', handleTopClick);
   }
 
-  const ids = ['topbtn', 'graphbtn', 'flamegraph', 'peek', 'list', 'disasm',
-               'focus', 'ignore', 'hide', 'show', 'show-from'];
+  const ids = ['topbtn', 'graphbtn', 'flamegraph', 'flamegraph2', 'peek', 'list',
+	       'disasm', 'focus', 'ignore', 'hide', 'show', 'show-from'];
   ids.forEach(makeSearchLinkDynamic);
 
   const sampleIDs = [{{range .SampleTypes}}'{{.}}', {{end}}];
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/header.html b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/header.html
index 66cabbbaa4..39cb55a1d1 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/header.html
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/header.html
@@ -12,6 +12,7 @@
       <a title="{{.Help.top}}"  href="./top" id="topbtn">Top</a>
       <a title="{{.Help.graph}}" href="./" id="graphbtn">Graph</a>
       <a title="{{.Help.flamegraph}}" href="./flamegraph" id="flamegraph">Flame Graph</a>
+      <a title="{{.Help.flamegraph2}}" href="./flamegraph2" id="flamegraph2">Flame Graph (new)</a>
       <a title="{{.Help.peek}}" href="./peek" id="peek">Peek</a>
       <a title="{{.Help.list}}" href="./source" id="list">Source</a>
       <a title="{{.Help.disasm}}" href="./disasm" id="disasm">Disassemble</a>
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.css b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.css
new file mode 100644
index 0000000000..d142aa789c
--- /dev/null
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.css
@@ -0,0 +1,80 @@
+body {
+  overflow: hidden; /* Want scrollbar not here, but in #stack-holder */
+}
+/* Scrollable container for flame graph */
+#stack-holder {
+  width: 100%;
+  flex-grow: 1;
+  overflow-y: auto;
+  background: #eee; /* Light grey gives better contrast with boxes */
+  position: relative; /* Allows absolute positioning of child boxes */
+}
+/* Flame graph */
+#stack-chart {
+  width: 100%;
+  position: relative; /* Allows absolute positioning of child boxes */
+}
+/* Shows details of frame that is under the mouse */
+#current-details {
+  position: absolute;
+  top: 5px;
+  right: 5px;
+  z-index: 2;
+  font-size: 12pt;
+}
+/* Background of a single flame-graph frame */
+.boxbg {
+  border-width: 0px;
+  position: absolute;
+  overflow: hidden;
+  box-sizing: border-box;
+}
+/* Not-inlined frames are visually separated from their caller. */
+.not-inlined {
+  border-top: 1px solid black;
+}
+/* Function name */
+.boxtext {
+  position: absolute;
+  width: 100%;
+  padding-left: 2px;
+  line-height: 18px;
+  cursor: default;
+  font-family: "Google Sans", Arial, sans-serif;
+  font-size: 12pt;
+  z-index: 2;
+}
+/* Box highlighting via shadows to avoid size changes */
+.hilite { box-shadow: 0px 0px 0px 2px #000; z-index: 1; }
+.hilite2 { box-shadow: 0px 0px 0px 2px #000; z-index: 1; }
+/* Self-cost region inside a box */
+.self {
+  position: absolute;
+  background: rgba(0,0,0,0.25); /* Darker hue */
+}
+/* Gap left between callers and callees */
+.separator {
+  position: absolute;
+  text-align: center;
+  font-size: 12pt;
+  font-weight: bold;
+}
+/* Ensure that pprof menu is above boxes */
+.submenu { z-index: 3; }
+/* Right-click menu */
+#action-menu {
+  max-width: 15em;
+}
+/* Right-click menu title */
+#action-title {
+  display: block;
+  padding: 0.5em 1em;
+  background: #888;
+  text-overflow: ellipsis;
+  overflow: hidden;
+}
+/* Internal canvas used to measure text size when picking fonts */
+#textsizer {
+  position: absolute;
+  bottom: -100px;
+}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.html b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.html
new file mode 100644
index 0000000000..1ddb7a3a1c
--- /dev/null
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>{{.Title}}</title>
+  {{template "css" .}}
+  {{template "stacks_css"}}
+</head>
+<body>
+  {{template "header" .}}
+  <div id="stack-holder">
+    <div id="stack-chart"></div>
+    <div id="current-details"></div>
+  </div>
+  <div id="action-menu" class="submenu">
+    <span id="action-title"></span>
+    <hr>
+    <a title="{{.Help.list}}" id="action-source" href="./source">Show source code</a>
+    <a title="{{.Help.list}}" id="action-source-tab" href="./source" target="_blank">Show source in new tab</a>
+    <hr>
+    <a title="{{.Help.focus}}" id="action-focus" href="?">Focus</a>
+    <a title="{{.Help.ignore}}" id="action-ignore" href="?">Ignore</a>
+    <a title="{{.Help.hide}}" id="action-hide" href="?">Hide</a>
+    <a title="{{.Help.show_from}}" id="action-showfrom" href="?">Show from</a>
+  </div>
+  {{template "script" .}}
+  {{template "stacks_js"}}
+  <script>
+    stackViewer({{.Stacks}}, {{.Nodes}});
+  </script>
+</body>
+</html>
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.js b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.js
new file mode 100644
index 0000000000..64229a000a
--- /dev/null
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/html/stacks.js
@@ -0,0 +1,524 @@
+// stackViewer displays a flame-graph like view (extended to show callers).
+//   stacks - report.StackSet
+//   nodes  - List of names for each source in report.StackSet
+function stackViewer(stacks, nodes) {
+  'use strict';
+
+  // Constants used in rendering.
+  const ROW = 20;
+  const PADDING = 2;
+  const MIN_WIDTH = 4;
+  const MIN_TEXT_WIDTH = 16;
+  const TEXT_MARGIN = 2;
+  const FONT_SIZE = 12;
+  const MIN_FONT_SIZE = 8;
+
+  // Mapping from unit to a list of display scales/labels.
+  // List should be ordered by increasing unit size.
+  const UNITS = new Map([
+    ['B', [
+      ['B', 1],
+      ['kB', Math.pow(2, 10)],
+      ['MB', Math.pow(2, 20)],
+      ['GB', Math.pow(2, 30)],
+      ['TB', Math.pow(2, 40)],
+      ['PB', Math.pow(2, 50)]]],
+    ['s', [
+      ['ns', 1e-9],
+      ['µs', 1e-6],
+      ['ms', 1e-3],
+      ['s', 1],
+      ['hrs', 60*60]]]]);
+
+  // Fields
+  let shownTotal = 0;       // Total value of all stacks
+  let pivots = [];          // Indices of currently selected data.Sources entries.
+  let matches = new Set();  // Indices of sources that match search
+  let elems = new Map();    // Mapping from source index to display elements
+  let displayList = [];     // List of boxes to display.
+  let actionMenuOn = false; // Is action menu visible?
+  let actionTarget = null;  // Box on which action menu is operating.
+
+  // Setup to allow measuring text width.
+  const textSizer = document.createElement('canvas');
+  textSizer.id = 'textsizer';
+  const textContext = textSizer.getContext('2d');
+
+  // Get DOM elements.
+  const chart = find('stack-chart');
+  const search = find('search');
+  const actions = find('action-menu');
+  const actionTitle = find('action-title');
+  const detailBox = find('current-details');
+
+  window.addEventListener('resize', render);
+  window.addEventListener('popstate', render);
+  search.addEventListener('keydown', handleSearchKey);
+
+  // Withdraw action menu when clicking outside, or when item selected.
+  document.addEventListener('mousedown', (e) => {
+    if (!actions.contains(e.target)) {
+      hideActionMenu();
+    }
+  });
+  actions.addEventListener('click', hideActionMenu);
+
+  // Initialize menus and other general UI elements.
+  viewer(new URL(window.location.href), nodes, {
+    hiliter: (n, on) => { return hilite(n, on); },
+    current: () => {
+      let r = new Map();
+      for (let p of pivots) {
+        r.set(p, true);
+      }
+      return r;
+    }});
+
+  render();
+
+  // Helper functions follow:
+
+  // hilite changes the highlighting of elements corresponding to specified src.
+  function hilite(src, on) {
+    if (on) {
+      matches.add(src);
+    } else {
+      matches.delete(src);
+    }
+    toggleClass(src, 'hilite', on);
+    return true;
+  }
+
+  // Display action menu (triggered by right-click on a frame)
+  function showActionMenu(e, box) {
+    if (box.src == 0) return; // No action menu for root
+    e.preventDefault(); // Disable browser context menu
+    const src = stacks.Sources[box.src];
+    actionTitle.innerText = src.Display[src.Display.length-1];
+    const menu = actions;
+    menu.style.display = 'block';
+    // Compute position so menu stays visible and near the mouse.
+    const x = Math.min(e.clientX - 10, document.body.clientWidth - menu.clientWidth);
+    const y = Math.min(e.clientY - 10, document.body.clientHeight - menu.clientHeight);
+    menu.style.left = x + 'px';
+    menu.style.top = y + 'px';
+    // Set menu links to operate on clicked box.
+    setHrefParam('action-source', 'f', box.src);
+    setHrefParam('action-source-tab', 'f', box.src);
+    setHrefParam('action-focus', 'f', box.src);
+    setHrefParam('action-ignore', 'i', box.src);
+    setHrefParam('action-hide', 'h', box.src);
+    setHrefParam('action-showfrom', 'sf', box.src);
+    toggleClass(box.src, 'hilite2', true);
+    actionTarget = box;
+    actionMenuOn = true;
+  }
+
+  function hideActionMenu() {
+    actions.style.display = 'none';
+    actionMenuOn = false;
+    if (actionTarget != null) {
+      toggleClass(actionTarget.src, 'hilite2', false);
+    }
+  }
+
+  // setHrefParam updates the specified parameter in the  href of an <a>
+  // element to make it operate on the specified src.
+  function setHrefParam(id, param, src) {
+    const elem = document.getElementById(id);
+    if (!elem) return;
+
+    let url = new URL(elem.href);
+    url.hash = '';
+
+    // Copy params from this page's URL.
+    const params = url.searchParams;
+    for (const p of new URLSearchParams(window.location.search)) {
+      params.set(p[0], p[1]);
+    }
+
+    // Update params to include src.
+    let v = stacks.Sources[src].RE;
+    if (param != 'f' && param != 'sf') { // old f,sf values are overwritten
+      // Add new source to current parameter value.
+      const old = params.get(param);
+      if (old && old != '') {
+        v += '|' + old;
+      }
+    }
+    params.set(param, v);
+
+    elem.href = url.toString();
+  }
+
+  // Capture Enter key in the search box to make it pivot instead of focus.
+  function handleSearchKey(e) {
+    if (e.key != 'Enter') return;
+    e.stopImmediatePropagation();  // Disable normal enter key handling
+    const val = search.value;
+    try {
+      new RegExp(search.value);
+    } catch (error) {
+      return;  // TODO: Display error state in search box
+    }
+    switchPivots(val);
+  }
+
+  function switchPivots(regexp) {
+    // Switch URL without hitting the server.
+    const url = new URL(document.URL);
+    url.searchParams.set('p', regexp);
+    history.pushState('', '', url.toString()); // Makes back-button work
+    matches = new Set();
+    search.value = '';
+    render();
+  }
+
+  function handleEnter(box, div) {
+    if (actionMenuOn) return;
+    const src = stacks.Sources[box.src];
+    const d = details(box);
+    div.title = d + ' ' + src.FullName + (src.Inlined ? "\n(inlined)" : "");
+    detailBox.innerText = d;
+    // Highlight all boxes that have the same source as box.
+    toggleClass(box.src, 'hilite2', true);
+  }
+
+  function handleLeave(box) {
+    if (actionMenuOn) return;
+    detailBox.innerText = '';
+    toggleClass(box.src, 'hilite2', false);
+  }
+
+  // Return list of sources that match the regexp given by the 'p' URL parameter.
+  function urlPivots() {
+    const pivots = [];
+    const params = (new URL(document.URL)).searchParams;
+    const val = params.get('p');
+    if (val !== null && val != '') {
+      try {
+        const re = new RegExp(val);
+        for (let i = 0; i < stacks.Sources.length; i++) {
+          const src = stacks.Sources[i];
+          if (re.test(src.UniqueName) || re.test(src.FileName)) {
+            pivots.push(i);
+          }
+        }
+      } catch (error) {}
+    }
+    if (pivots.length == 0) {
+      pivots.push(0);
+    }
+    return pivots;
+  }
+
+  // render re-generates the stack display.
+  function render() {
+    pivots = urlPivots();
+
+    // Get places where pivots occur.
+    let places = [];
+    for (let pivot of pivots) {
+      const src = stacks.Sources[pivot];
+      for (let p of src.Places) {
+        places.push(p);
+      }
+    }
+
+    const width = chart.clientWidth;
+    elems.clear();
+    actionTarget = null;
+    const total = totalValue(places);
+    const xscale = (width-2*PADDING) / total; // Converts from profile value to X pixels
+    const x = PADDING;
+    const y = 0;
+    shownTotal = total;
+
+    displayList.length = 0;
+    renderStacks(0, xscale, x, y, places, +1);  // Callees
+    renderStacks(0, xscale, x, y-ROW, places, -1);  // Callers (ROW left for separator)
+    display(displayList);
+  }
+
+  // renderStacks creates boxes with top-left at x,y with children drawn as
+  // nested stacks (below or above based on the sign of direction).
+  // Returns the largest y coordinate filled.
+  function renderStacks(depth, xscale, x, y, places, direction) {
+    // Example: suppose we are drawing the following stacks:
+    //   a->b->c
+    //   a->b->d
+    //   a->e->f
+    // After rendering a, we will call renderStacks, with places pointing to
+    // the preceding stacks.
+    //
+    // We first group all places with the same leading entry. In this example
+    // we get [b->c, b->d] and [e->f]. We render the two groups side-by-side.
+    const groups = partitionPlaces(places);
+    for (const g of groups) {
+      renderGroup(depth, xscale, x, y, g, direction);
+      x += xscale*g.sum;
+    }
+  }
+
+  function renderGroup(depth, xscale, x, y, g, direction) {
+    // Skip if not wide enough.
+    const width = xscale * g.sum;
+    if (width < MIN_WIDTH) return;
+
+    // Draw the box for g.src (except for selected element in upwards direction
+    // since that duplicates the box we added in downwards direction).
+    if (depth != 0 || direction > 0) {
+      const box = {
+        x:         x,
+        y:         y,
+        src:       g.src,
+        sum:       g.sum,
+        selfValue: g.self,
+        width:     xscale*g.sum,
+        selfWidth: (direction > 0) ? xscale*g.self : 0,
+      };
+      displayList.push(box);
+      x += box.selfWidth;
+    }
+    y += direction * ROW;
+
+    // Find child or parent stacks.
+    const next = [];
+    for (const place of g.places) {
+      const stack = stacks.Stacks[place.Stack];
+      const nextSlot = place.Pos + direction;
+      if (nextSlot >= 0 && nextSlot < stack.Sources.length) {
+        next.push({Stack: place.Stack, Pos: nextSlot});
+      }
+    }
+    renderStacks(depth+1, xscale, x, y, next, direction);
+  }
+
+  // partitionPlaces partitions a set of places into groups where each group
+  // contains places with the same source. If a stack occurs multiple times
+  // in places, only the outer-most occurrence is kept.
+  function partitionPlaces(places) {
+    // Find outer-most slot per stack (used later to elide duplicate stacks).
+    const stackMap = new Map();  // Map from stack index to outer-most slot#
+    for (const place of places) {
+      const prevSlot = stackMap.get(place.Stack);
+      if (prevSlot && prevSlot <= place.Pos) {
+        // We already have a higher slot in this stack.
+      } else {
+        stackMap.set(place.Stack, place.Pos);
+      }
+    }
+
+    // Now partition the stacks.
+    const groups = [];           // Array of Group {name, src, sum, self, places}
+    const groupMap = new Map();  // Map from Source to Group
+    for (const place of places) {
+      if (stackMap.get(place.Stack) != place.Pos) {
+        continue;
+      }
+
+      const stack = stacks.Stacks[place.Stack];
+      const src = stack.Sources[place.Pos];
+      let group = groupMap.get(src);
+      if (!group) {
+        const name = stacks.Sources[src].FullName;
+        group = {name: name, src: src, sum: 0, self: 0, places: []};
+        groupMap.set(src, group);
+        groups.push(group);
+      }
+      group.sum += stack.Value;
+      group.self += (place.Pos == stack.Sources.length-1) ? stack.Value : 0;
+      group.places.push(place);
+    }
+
+    // Order by decreasing cost (makes it easier to spot heavy functions).
+    // Though alphabetical ordering is a potential alternative that will make
+    // profile comparisons easier.
+    groups.sort(function(a, b) { return b.sum - a.sum; });
+
+    return groups;
+  }
+
+  function display(list) {
+    // Sort boxes so that text selection follows a predictable order.
+    list.sort(function(a, b) {
+      if (a.y != b.y) return a.y - b.y;
+      return a.x - b.x;
+    });
+
+    // Adjust Y coordinates so that zero is at top.
+    let adjust = (list.length > 0) ? list[0].y : 0;
+    adjust -= ROW + 2*PADDING;  // Room for details
+
+    const divs = [];
+    for (const box of list) {
+      box.y -= adjust;
+      divs.push(drawBox(box));
+    }
+    divs.push(drawSep(-adjust));
+
+    const h = (list.length > 0 ?  list[list.length-1].y : 0) + 4*ROW;
+    chart.style.height = h+'px';
+    chart.replaceChildren(...divs);
+  }
+
+  function drawBox(box) {
+    const srcIndex = box.src;
+    const src = stacks.Sources[srcIndex];
+
+    // Background
+    const w = box.width - 1; // Leave 1px gap
+    const r = document.createElement('div');
+    r.style.left = box.x + 'px';
+    r.style.top = box.y + 'px';
+    r.style.width = w + 'px';
+    r.style.height = ROW + 'px';
+    r.classList.add('boxbg');
+    r.style.background = makeColor(src.Color);
+    addElem(srcIndex, r);
+    if (!src.Inlined) {
+      r.classList.add('not-inlined');
+    }
+
+    // Box that shows time spent in self
+    if (box.selfWidth >= MIN_WIDTH) {
+      const s = document.createElement('div');
+      s.style.width = Math.min(box.selfWidth, w)+'px';
+      s.style.height = (ROW-1)+'px';
+      s.classList.add('self');
+      r.appendChild(s);
+    }
+
+    // Label
+    if (box.width >= MIN_TEXT_WIDTH) {
+      const t = document.createElement('div');
+      t.classList.add('boxtext');
+      fitText(t, box.width-2*TEXT_MARGIN, src.Display);
+      r.appendChild(t);
+    }
+
+    r.addEventListener('click', () => { switchPivots(src.RE); });
+    r.addEventListener('mouseenter', () => { handleEnter(box, r); });
+    r.addEventListener('mouseleave', () => { handleLeave(box); });
+    r.addEventListener('contextmenu', (e) => { showActionMenu(e, box); });
+    return r;
+  }
+
+  function drawSep(y) {
+    const m = document.createElement('div');
+    m.innerText = percent(shownTotal, stacks.Total) +
+	'\xa0\xa0\xa0\xa0' +  // Some non-breaking spaces
+	valueString(shownTotal);
+    m.style.top = (y-ROW) + 'px';
+    m.style.left = PADDING + 'px';
+    m.style.width = (chart.clientWidth - PADDING*2) + 'px';
+    m.classList.add('separator');
+    return m;
+  }
+
+  // addElem registers an element that belongs to the specified src.
+  function addElem(src, elem) {
+    let list = elems.get(src);
+    if (!list) {
+      list = [];
+      elems.set(src, list);
+    }
+    list.push(elem);
+    elem.classList.toggle('hilite', matches.has(src));
+  }
+
+  // Adds or removes cl from classList of all elements for the specified source.
+  function toggleClass(src, cl, value) {
+    const list = elems.get(src);
+    if (list) {
+      for (const elem of list) {
+        elem.classList.toggle(cl, value);
+      }
+    }
+  }
+
+  // fitText sets text and font-size clipped to the specified width w.
+  function fitText(t, avail, textList) {
+    // Find first entry in textList that fits.
+    let width = avail;
+    textContext.font = FONT_SIZE + 'pt Arial';
+    for (let i = 0; i < textList.length; i++) {
+      let text = textList[i];
+      width = textContext.measureText(text).width;
+      if (width <= avail) {
+        t.innerText = text;
+        return;
+      }
+    }
+
+    // Try to fit by dropping font size.
+    let text = textList[textList.length-1];
+    const fs = Math.max(MIN_FONT_SIZE, FONT_SIZE * (avail / width));
+    t.style.fontSize = fs + 'pt';
+    t.innerText = text;
+  }
+
+  // totalValue returns the combined sum of the stacks listed in places.
+  function totalValue(places) {
+    const seen = new Set();
+    let result = 0;
+    for (const place of places) {
+      if (seen.has(place.Stack)) continue; // Do not double-count stacks
+      seen.add(place.Stack);
+      const stack = stacks.Stacks[place.Stack];
+      result += stack.Value;
+    }
+    return result;
+  }
+
+  function details(box) {
+    // E.g., 10% 7s
+    // or    10% 7s (3s self
+    let result = percent(box.sum, stacks.Total) + ' ' + valueString(box.sum);
+    if (box.selfValue > 0) {
+      result += ` (${valueString(box.selfValue)} self)`;
+    }
+    return result;
+  }
+
+  function percent(v, total) {
+    return Number(((100.0 * v) / total).toFixed(1)) + '%';
+  }
+
+  // valueString returns a formatted string to display for value.
+  function valueString(value) {
+    let v = value * stacks.Scale;
+    // Rescale to appropriate display unit.
+    let unit = stacks.Unit;
+    const list = UNITS.get(unit);
+    if (list) {
+      // Find first entry in list that is not too small.
+      for (const [name, scale] of list) {
+        if (v <= 100*scale) {
+          v /= scale;
+          unit = name;
+          break;
+        }
+      }
+    }
+    return Number(v.toFixed(2)) + unit;
+  }
+
+  function find(name) {
+    const elem = document.getElementById(name);
+    if (!elem) {
+      throw 'element not found: ' + name
+    }
+    return elem;
+  }
+
+  function makeColor(index) {
+    // Rotate hue around a circle. Multiple by phi to spread things
+    // out better. Use 50% saturation to make subdued colors, and
+    // 80% lightness to have good contrast with black foreground text.
+    const PHI = 1.618033988;
+    const hue = (index+1) * PHI * 2 * Math.PI; // +1 to avoid 0
+    const hsl = `hsl(${hue}rad 50% 80%)`;
+    return hsl;
+  }
+}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive.go
index 777fb90bfb..e6e865f385 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive.go
@@ -42,6 +42,7 @@ func interactive(p *profile.Profile, o *plugin.Options) error {
 	interactiveMode = true
 	shortcuts := profileShortcuts(p)
 
+	copier := makeProfileCopier(p)
 	greetings(p, o.UI)
 	for {
 		input, err := o.UI.ReadLine("(pprof) ")
@@ -110,7 +111,7 @@ func interactive(p *profile.Profile, o *plugin.Options) error {
 
 			args, cfg, err := parseCommandLine(tokens)
 			if err == nil {
-				err = generateReportWrapper(p, args, cfg, o)
+				err = generateReportWrapper(copier.newCopy(), args, cfg, o)
 			}
 
 			if err != nil {
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/settings.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/settings.go
index 1e9154c5f5..b784618aca 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/settings.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/settings.go
@@ -3,7 +3,6 @@ package driver
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -33,7 +32,7 @@ func settingsFileName() (string, error) {
 
 // readSettings reads settings from fname.
 func readSettings(fname string) (*settings, error) {
-	data, err := ioutil.ReadFile(fname)
+	data, err := os.ReadFile(fname)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return &settings{}, nil
@@ -64,7 +63,7 @@ func writeSettings(fname string, settings *settings) error {
 		return fmt.Errorf("failed to create settings directory: %w", err)
 	}
 
-	if err := ioutil.WriteFile(fname, data, 0644); err != nil {
+	if err := os.WriteFile(fname, data, 0644); err != nil {
 		return fmt.Errorf("failed to write settings: %w", err)
 	}
 	return nil
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/stacks.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/stacks.go
new file mode 100644
index 0000000000..249dfe0742
--- /dev/null
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/stacks.go
@@ -0,0 +1,58 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package driver
+
+import (
+	"encoding/json"
+	"html/template"
+	"net/http"
+
+	"github.com/google/pprof/internal/report"
+)
+
+// stackView generates the new flamegraph view.
+func (ui *webInterface) stackView(w http.ResponseWriter, req *http.Request) {
+	// Get all data in a report.
+	rpt, errList := ui.makeReport(w, req, []string{"svg"}, func(cfg *config) {
+		cfg.CallTree = true
+		cfg.Trim = false
+		cfg.Granularity = "filefunctions"
+	})
+	if rpt == nil {
+		return // error already reported
+	}
+
+	// Make stack data and generate corresponding JSON.
+	stacks := rpt.Stacks()
+	b, err := json.Marshal(stacks)
+	if err != nil {
+		http.Error(w, "error serializing stacks for flame graph",
+			http.StatusInternalServerError)
+		ui.options.UI.PrintErr(err)
+		return
+	}
+
+	nodes := make([]string, len(stacks.Sources))
+	for i, src := range stacks.Sources {
+		nodes[i] = src.FullName
+	}
+	nodes[0] = "" // root is not a real node
+
+	_, legend := report.TextItems(rpt)
+	ui.render(w, req, "stacks", rpt, errList, legend, webArgs{
+		Stacks: template.JS(b),
+		Nodes:  nodes,
+	})
+}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/tagroot.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/tagroot.go
index c43d599982..76a594d9f7 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/tagroot.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/tagroot.go
@@ -97,6 +97,10 @@ func addLabelNodes(p *profile.Profile, rootKeys, leafKeys []string, outputUnit s
 			leafm = true
 		}
 
+		if len(leavesToAdd)+len(rootsToAdd) == 0 {
+			continue
+		}
+
 		var newLocs []*profile.Location
 		newLocs = append(newLocs, leavesToAdd...)
 		newLocs = append(newLocs, s.Location...)
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/webhtml.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/webhtml.go
index 94f32e3755..55973ffb9f 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/webhtml.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/webhtml.go
@@ -65,4 +65,7 @@ func addTemplates(templates *template.Template) {
 	def("sourcelisting", loadFile("html/source.html"))
 	def("plaintext", loadFile("html/plaintext.html"))
 	def("flamegraph", loadFile("html/flamegraph.html"))
+	def("stacks", loadFile("html/stacks.html"))
+	def("stacks_css", loadCSS("html/stacks.css"))
+	def("stacks_js", loadJS("html/stacks.js"))
 }
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go
index 0f3e8bf93c..8881e39eb2 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go
@@ -36,13 +36,14 @@ import (
 // webInterface holds the state needed for serving a browser based interface.
 type webInterface struct {
 	prof         *profile.Profile
+	copier       profileCopier
 	options      *plugin.Options
 	help         map[string]string
 	templates    *template.Template
 	settingsFile string
 }
 
-func makeWebInterface(p *profile.Profile, opt *plugin.Options) (*webInterface, error) {
+func makeWebInterface(p *profile.Profile, copier profileCopier, opt *plugin.Options) (*webInterface, error) {
 	settingsFile, err := settingsFileName()
 	if err != nil {
 		return nil, err
@@ -52,6 +53,7 @@ func makeWebInterface(p *profile.Profile, opt *plugin.Options) (*webInterface, e
 	report.AddSourceTemplates(templates)
 	return &webInterface{
 		prof:         p,
+		copier:       copier,
 		options:      opt,
 		help:         make(map[string]string),
 		templates:    templates,
@@ -86,6 +88,7 @@ type webArgs struct {
 	TextBody    string
 	Top         []report.TextItem
 	FlameGraph  template.JS
+	Stacks      template.JS
 	Configs     []configMenuEntry
 }
 
@@ -95,7 +98,8 @@ func serveWebInterface(hostport string, p *profile.Profile, o *plugin.Options, d
 		return err
 	}
 	interactiveMode = true
-	ui, err := makeWebInterface(p, o)
+	copier := makeProfileCopier(p)
+	ui, err := makeWebInterface(p, copier, o)
 	if err != nil {
 		return err
 	}
@@ -107,6 +111,8 @@ func serveWebInterface(hostport string, p *profile.Profile, o *plugin.Options, d
 	}
 	ui.help["details"] = "Show information about the profile and this view"
 	ui.help["graph"] = "Display profile as a directed graph"
+	ui.help["flamegraph"] = "Display profile as a flame graph"
+	ui.help["flamegraph2"] = "Display profile as a flame graph (experimental version that can display caller info on selection)"
 	ui.help["reset"] = "Show the entire profile"
 	ui.help["save_config"] = "Save current settings"
 
@@ -125,6 +131,7 @@ func serveWebInterface(hostport string, p *profile.Profile, o *plugin.Options, d
 			"/source":       http.HandlerFunc(ui.source),
 			"/peek":         http.HandlerFunc(ui.peek),
 			"/flamegraph":   http.HandlerFunc(ui.flamegraph),
+			"/flamegraph2":  http.HandlerFunc(ui.stackView), // Experimental
 			"/saveconfig":   http.HandlerFunc(ui.saveConfig),
 			"/deleteconfig": http.HandlerFunc(ui.deleteConfig),
 			"/download": http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
@@ -262,7 +269,7 @@ func (ui *webInterface) makeReport(w http.ResponseWriter, req *http.Request,
 	catcher := &errorCatcher{UI: ui.options.UI}
 	options := *ui.options
 	options.UI = catcher
-	_, rpt, err := generateRawReport(ui.prof, cmd, cfg, &options)
+	_, rpt, err := generateRawReport(ui.copier.newCopy(), cmd, cfg, &options)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		ui.options.UI.PrintErr(err)