1 files changed, 43 insertions, 21 deletions

diff --git a/src/cmd/compile/internal/ssa/html.go b/src/cmd/compile/internal/ssa/html.go
index ba37a80412..a9d52fa4ee 100644
--- a/src/cmd/compile/internal/ssa/html.go
+++ b/src/cmd/compile/internal/ssa/html.go
@@ -28,18 +28,23 @@ type HTMLWriter struct {
 }
 
 func NewHTMLWriter(path string, f *Func, cfgMask string) *HTMLWriter {
+	path = strings.Replace(path, "/", string(filepath.Separator), -1)
 	out, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 	if err != nil {
 		f.Fatalf("%v", err)
 	}
-	pwd, err := os.Getwd()
-	if err != nil {
-		f.Fatalf("%v", err)
+	reportPath := path
+	if !filepath.IsAbs(reportPath) {
+		pwd, err := os.Getwd()
+		if err != nil {
+			f.Fatalf("%v", err)
+		}
+		reportPath = filepath.Join(pwd, path)
 	}
 	html := HTMLWriter{
 		w:    out,
 		Func: f,
-		path: filepath.Join(pwd, path),
+		path: reportPath,
 		dot:  newDotWriter(cfgMask),
 	}
 	html.start()
@@ -119,7 +124,8 @@ td.collapsed {
 }
 
 td.collapsed div {
-    /* TODO: Flip the direction of the phase's title 90 degrees on a collapsed column. */
+    text-align: right;
+    transform: rotate(180deg);
     writing-mode: vertical-lr;
     white-space: pre;
 }
@@ -357,6 +363,21 @@ body.darkmode ellipse.outline-black { outline: gray solid 2px; }
 </style>
 
 <script type="text/javascript">
+
+// Contains phase names which are expanded by default. Other columns are collapsed.
+let expandedDefault = [
+    "start",
+    "deadcode",
+    "opt",
+    "lower",
+    "late-deadcode",
+    "regalloc",
+    "genssa",
+];
+if (history.state === null) {
+    history.pushState({expandedDefault}, "", location.href);
+}
+
 // ordered list of all available highlight colors
 var highlights = [
     "highlight-aquamarine",
@@ -401,6 +422,9 @@ for (var i = 0; i < outlines.length; i++) {
 }
 
 window.onload = function() {
+    if (history.state !== null) {
+        expandedDefault = history.state.expandedDefault;
+    }
     if (window.matchMedia && window.matchMedia("(prefers-color-scheme: dark)").matches) {
         toggleDarkMode();
         document.getElementById("dark-mode-button").checked = true;
@@ -409,9 +433,6 @@ window.onload = function() {
     var ssaElemClicked = function(elem, event, selections, selected) {
         event.stopPropagation();
 
-        // TODO: pushState with updated state and read it on page load,
-        // so that state can survive across reloads
-
         // find all values with the same name
         var c = elem.classList.item(0);
         var x = document.getElementsByClassName(c);
@@ -489,21 +510,18 @@ window.onload = function() {
         lines[i].addEventListener('click', ssaValueClicked);
     }
 
-    // Contains phase names which are expanded by default. Other columns are collapsed.
-    var expandedDefault = [
-        "start",
-        "deadcode",
-        "opt",
-        "lower",
-        "late-deadcode",
-        "regalloc",
-        "genssa",
-    ];
 
     function toggler(phase) {
         return function() {
             toggle_cell(phase+'-col');
             toggle_cell(phase+'-exp');
+            const i = expandedDefault.indexOf(phase);
+            if (i !== -1) {
+                expandedDefault.splice(i, 1);
+            } else {
+                expandedDefault.push(phase);
+            }
+            history.pushState({expandedDefault}, "", location.href);
         };
     }
 
@@ -531,9 +549,13 @@ window.onload = function() {
             const len = combined.length;
             if (len > 1) {
                 for (let i = 0; i < len; i++) {
-                    if (expandedDefault.indexOf(combined[i]) !== -1) {
-                        show = true;
-                        break;
+                    const num = expandedDefault.indexOf(combined[i]);
+                    if (num !== -1) {
+                        expandedDefault.splice(num, 1);
+                        if (expandedDefault.indexOf(phase) === -1) {
+                            expandedDefault.push(phase);
+                            show = true;
+                        }
                     }
                 }
             }