Remove recursion in filterThreadToSearchString (#5572)

Profile showing before/after: https://share.firefox.dev/45Ogp1l

The previous implementation was recursing to check whether the parent
stack matches the search filter. With some profiles I was seeing JS
stack exhaustion exceptions, but only on localhost:4242 with the
development environment, not in the production environment.

Author: canova

src/profile-logic/profile-data.ts

@@ -25,7 +25,7 @@ import {
 } from 'firefox-profiler/app-logic/constants';
 import { timeCode } from 'firefox-profiler/utils/time-code';
 import { bisectionRight, bisectionLeft } from 'firefox-profiler/utils/bisect';
-import { makeBitSet } from 'firefox-profiler/utils/bitset';
+import { checkBit, makeBitSet, setBit } from 'firefox-profiler/utils/bitset';
 import { parseFileNameFromSymbolication } from 'firefox-profiler/utils/special-paths';
 import { StringTable } from 'firefox-profiler/utils/string-table';
 import {
@@ -1504,7 +1504,7 @@ export function filterThreadToSearchString(
   const { funcTable, frameTable, stackTable, stringTable, resourceTable } =
     thread;
 
-  function computeFuncMatchesFilter(func: IndexIntoFuncTable) {
+  function computeFuncMatchesSearch(func: IndexIntoFuncTable) {
     const nameIndex = funcTable.name[func];
     const nameString = stringTable.getString(nameIndex);
     if (nameString.toLowerCase().includes(lowercaseSearchString)) {
@@ -1531,38 +1531,32 @@ export function filterThreadToSearchString(
     return false;
   }
 
-  const funcMatchesFilterCache = new Map();
-  function funcMatchesFilter(func: IndexIntoFuncTable) {
-    let result = funcMatchesFilterCache.get(func);
-    if (result === undefined) {
-      result = computeFuncMatchesFilter(func);
-      funcMatchesFilterCache.set(func, result);
+  const funcMatchesSearch = makeBitSet(funcTable.length);
+  for (let funcIndex = 0; funcIndex < funcTable.length; funcIndex++) {
+    if (computeFuncMatchesSearch(funcIndex)) {
+      setBit(funcMatchesSearch, funcIndex);
     }
-    return result;
   }
 
-  const stackMatchesFilterCache = new Map();
-  function stackMatchesFilter(stackIndex: IndexIntoStackTable | null) {
-    if (stackIndex === null) {
-      return false;
-    }
-    let result = stackMatchesFilterCache.get(stackIndex);
-    if (result === undefined) {
-      const prefix = stackTable.prefix[stackIndex];
-      if (stackMatchesFilter(prefix)) {
-        result = true;
-      } else {
-        const frame = stackTable.frame[stackIndex];
-        const func = frameTable.func[frame];
-        result = funcMatchesFilter(func);
+  const stackMatchesSearch = makeBitSet(funcTable.length);
+  for (let stackIndex = 0; stackIndex < stackTable.length; stackIndex++) {
+    const prefix = stackTable.prefix[stackIndex];
+    if (prefix !== null && checkBit(stackMatchesSearch, prefix)) {
+      setBit(stackMatchesSearch, stackIndex);
+    } else {
+      const funcIndex = frameTable.func[stackTable.frame[stackIndex]];
+      if (checkBit(funcMatchesSearch, funcIndex)) {
+        setBit(stackMatchesSearch, stackIndex);
       }
-      stackMatchesFilterCache.set(stackIndex, result);
     }
-    return result;
   }
 
+  // Set any stacks which don't include the search string to null.
+  // TODO: This includes stacks in markers; maybe we shouldn't clear marker stacks?
   return updateThreadStacks(thread, stackTable, (stackIndex) =>
-    stackMatchesFilter(stackIndex) ? stackIndex : null
+    stackIndex !== null && checkBit(stackMatchesSearch, stackIndex)
+      ? stackIndex
+      : null
   );
 }