perf(jsc): carry stack coordinate cache into rebased release

.github/openclaw/qualification/stack/check-jsc.sh

@@ -3,14 +3,17 @@ set -euo pipefail
 : "${WEBKIT_CHECKOUT:?}" "${JSC:?}" "${RESULT_DIR:?}"
 mkdir -p "$RESULT_DIR"
 cd "$WEBKIT_CHECKOUT"
-for mode in default interpreter optimizer eager-ftl; do
+for mode in default interpreter baseline dfg optimizer eager-ftl concurrent; do
  args=()
  case "$mode" in
  interpreter) args=(--useJIT=false);;
+ baseline) args=(--useDFGJIT=false --useFTLJIT=false);;
+ dfg) args=(--useFTLJIT=false --useConcurrentJIT=false);;
  optimizer) args=(--useBytecodeOptimizer=true);;
- eager-ftl) args=(--useConcurrentJIT=false --thresholdForOptimizeAfterWarmUp=10 --thresholdForFTLOptimizeAfterWarmUp=20);;
+ eager-ftl) args=(--useConcurrentJIT=false --thresholdForJITAfterWarmUp=10 --thresholdForOptimizeAfterWarmUp=10 --thresholdForFTLOptimizeAfterWarmUp=20);;
+ concurrent) args=(--gcAtEnd=true --useConcurrentGC=true);;
  esac
- for fixture in callsite-syntax-positions.js stack-position-regressions.js callsite-async-position.mjs; do
+ for fixture in callsite-syntax-positions.js stack-position-regressions.js stack-position-regressions-cache.js callsite-async-position.mjs; do
   module=(); case "$fixture" in *.mjs) module=(-m);; esac
   "$JSC" "${args[@]}" "${module[@]}" "JSTests/stress/$fixture" > "$RESULT_DIR/$mode-$fixture.log" 2>&1
  done
@@ -21,7 +24,7 @@ for kind in owned persistent; do
  args=(--diskCachePath="$cache")
  if test "$kind" = persistent; then args+=(--diskCachePayloadIsPersistentForTesting=true); fi
  for repeat in cold warm; do
-  for fixture in callsite-syntax-positions.js stack-position-regressions.js callsite-async-position.mjs; do
+  for fixture in callsite-syntax-positions.js stack-position-regressions.js stack-position-regressions-cache.js callsite-async-position.mjs; do
    module=(); case "$fixture" in *.mjs) module=(-m);; esac
    "$JSC" "${args[@]}" "${module[@]}" "JSTests/stress/$fixture" > "$RESULT_DIR/cache-$kind-$repeat-$fixture.log" 2>&1
   done

.github/openclaw/qualify-engine.sh

@@ -8,9 +8,9 @@ tar -xzf "$ARTIFACT_DIR/bun-webkit-linux-amd64.tar.gz" -C "$QUALIFICATION_DIR/en
 jsc="$QUALIFICATION_DIR/engine/bun-webkit/bin/jsc"
 "$jsc" --useDollarVM=true -e 'if(typeof $vm.moduleNamespaceForRequire!=="function")throw Error("namespace hook absent")'
 Tools/Scripts/run-jsc-stress-tests JSTests/stress --jsc "$jsc" --child-processes 16 \
-  --filter 'promise|microtask|dynamic-import|bun-async-context|module-loader|top-level-await|async-module|module-namespace|intl-segmenter|callsite-syntax-positions|stack-position-regressions' \
+  --filter 'promise|microtask|dynamic-import|bun-async-context|module-loader|top-level-await|async-module|module-namespace|intl-segmenter|callsite-syntax-positions|stack-position-regressions|error-stack' \
   --output-dir "$QUALIFICATION_DIR/jsc-stress" --no-retry > "$QUALIFICATION_DIR/jsc-stress.log" 2>&1
-python3 .github/openclaw/verify-jsc-results.py "$QUALIFICATION_DIR/jsc-stress" --require module-namespace-esmodule-marker.js --require callsite-syntax-positions.js --require stack-position-regressions.js
+python3 .github/openclaw/verify-jsc-results.py "$QUALIFICATION_DIR/jsc-stress" --require module-namespace-esmodule-marker.js --require callsite-syntax-positions.js --require stack-position-regressions.js --require stack-position-regressions-cache.js
 python3 .github/openclaw/check-stack-visitor.py "$jsc" > "$QUALIFICATION_DIR/stack-visitor.log"
 WEBKIT_CHECKOUT="$PWD" JSC="$jsc" RESULT_DIR="$QUALIFICATION_DIR/jsc-stack" bash .github/openclaw/qualification/stack/check-jsc.sh
 Tools/Scripts/run-jsc-stress-tests JSTests/modules.yaml --jsc "$jsc" --child-processes 16 \
@@ -38,5 +38,5 @@ for name,minimum in [('jsc-stress',1400),('jsc-modules',1600)]:
     assert len(lines)>=minimum,(name,len(lines))
     assert all(line.endswith(': PASS') for line in lines),name+' failures'
     counts[name]=len(lines)
-(root/'engine-gate.json').write_text(json.dumps({'passed':True,'source':sys.argv[2],'stress_counts':counts,'sampling_tiers':4,'arraybuffer_execution_modes':5,'stack_execution_modes':4,'stack_cache':json.loads((root/'jsc-stack/cache-files.json').read_text())},indent=2)+'\n')
+(root/'engine-gate.json').write_text(json.dumps({'passed':True,'source':sys.argv[2],'stress_counts':counts,'sampling_tiers':4,'arraybuffer_execution_modes':5,'stack_execution_modes':7,'stack_cache':json.loads((root/'jsc-stack/cache-files.json').read_text())},indent=2)+'\n')
 PY

.github/openclaw/release-notes.md

@@ -1,4 +1,8 @@
-This release rebases the qualified OpenClaw engine patches onto upstream `5718a6ec579b98362ea7276a426deedcc6281ef5`.
+This release adds engine PR #8's repeated stack-coordinate cache to the qualified OpenClaw engine on upstream `5718a6ec579b98362ea7276a426deedcc6281ef5`.
+
+- Cache requested provider-relative stack line and column conversions under the existing line-table lock, preserving document offsets, builtin overrides, and persistent bytecode format; thanks @steipete. Regressions cover repeated reads, independent providers, UTF-16 columns, and compressed line-table boundaries across interpreter/JIT tiers and cache modes.
+
+The previously released engine changes remain included:
 
 - Release free allocator memory from idle compiler threads and long Atomics waits; thanks @Jarred-Sumner.
 - Preserve Segmenter surrogate boundaries, opt-in Proxy global prototypes, module-loader AsyncLocalStorage context, and per-VM worker heap/stack budgets; thanks @steipete and @robobun.

.github/workflows/openclaw-checks.yml

@@ -16,7 +16,8 @@ jobs:
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
         with:
-          fetch-depth: 64
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
+          fetch-depth: 0
           persist-credentials: false
           sparse-checkout-cone-mode: false
           sparse-checkout: |
@@ -86,3 +87,27 @@ jobs:
             ${{ runner.temp }}/qualification/sync/runtime-cache/*.json
           if-no-files-found: error
           retention-days: 7
+  macos-fork-artifact:
+    if: github.repository == 'openclaw/WebKit'
+    runs-on: blacksmith-32vcpu-ubuntu-2404
+    timeout-minutes: 150
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
+          fetch-depth: 0
+          persist-credentials: false
+          sparse-checkout-cone-mode: false
+          sparse-checkout: |
+            /*
+            !/LayoutTests/
+            !/JSTests/*
+            !/PerformanceTests/
+            !/Websites/
+            !/ManualTests/
+            !/WebDriverTests/
+      - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020
+        with:
+          node-version: '26.3.0'
+      - name: Build the macOS fork artifact on Linux without publishing
+        run: python3 .github/openclaw/artifacts.py build --lane bun-webkit-macos-arm64 --output "$RUNNER_TEMP/macos-fork-artifact"

JSTests/stress/stack-position-regressions-cache.js

@@ -0,0 +1,20 @@
+// Exercise cached offsets from independent providers, including equal offsets
+// with different line tables, UTF-16 columns, and compressed-table boundaries.
+const sources = [];
+for (const terminator of ["\n", "\r\n", "\u2028", "\u2029"]) {
+    for (const lines of [0, 1, 63, 64, 65, 127]) {
+        const prefix = "/* 🦞 */ ";
+        const body = prefix + "(function positionCacheProbe() { return new Error('cache'); })";
+        const source = terminator.repeat(lines) + body;
+        sources.push({ create: eval(source), line: lines + 1, column: body.indexOf("new Error") + 1 });
+    }
+}
+for (let repeat = 0; repeat < Math.min(testLoopCount, 30); ++repeat) {
+    for (const { create, line, column } of sources) {
+        const error = create();
+        // Anonymous eval frames omit their URL from stack strings, but expose
+        // the same computed coordinates through JSC's error properties.
+        if (error.line !== line || error.column !== column)
+            throw new Error(`Expected ${line}:${column}, got ${error.line}:${error.column}`);
+    }
+}

OPENCLAW.md

@@ -54,8 +54,11 @@ Batch 1 is published from `openclaw/batch-1` so concurrently reviewed batch-2
 engine changes can land on `openclaw/main` without entering this release. All publication
 branches require the same protected environment and full-SHA/green-job checks.
 
-Pull requests run **OpenClaw engine checks**, a read-only Linux build using the same
-lane recipe and Bun qualification gate. It also runs the ArrayBuffer accounting
+Pull requests run **OpenClaw engine checks** at the exact PR head, with a native
+Linux build using the same lane recipe and Bun qualification gate, plus the
+macOS arm64 fork artifact cross-built on a separate Linux runner. Both jobs are
+read-only; the macOS lane proves compilation, not native macOS execution.
+The native job also runs the ArrayBuffer accounting
 and confirmed parked-waiter inspection regression with LLInt, DFG, FTL and
 concurrent GC. This workflow provides the pre-merge check; it cannot publish.
 
@@ -145,6 +148,12 @@ baseline. Engine and Bun headers and libraries must be rebuilt together.
 
 No changes yet.
 
+## Repeated stack coordinates (2026-10-05)
+
+- Cache source-relative stack line and column lookups on demand, including syntax-selected positions; carries engine PR #8 onto the rebased release line, thanks @steipete.
+- Build both fork engine artifacts at the exact pull-request head before landing, with native Linux qualification and a Linux-hosted macOS arm64 compilation check.
+- Require the repeated-coordinate regression and surrounding error-stack stress cases, with seven direct stack execution modes including interpreter, baseline-only, DFG-only, eager FTL and concurrent GC, while retaining every rebased release gate.
+
 ## Rebased engine batch
 
 - Keep syntax-selected stack positions separate from exception ranges for calls, constructors, property reads, and async continuations. Preserve the positions across bytecode rewriting, optimization, and cache replay.
@@ -222,3 +231,9 @@ regressions. A combined regression inspects a worker during the new idle-memory
 purge and notification windows. VM inspection runs before the idle-purge branch,
 with the waiter-list lock dropped and VM heap access restored only for inspection;
 both paths recheck notification/termination before waiting again.
+
+The source provider caches only requested line/column conversions under its existing
+line-table lock. Coordinates remain relative to the provider's text; document
+offsets and builtin provider overrides retain their existing behavior. The cache
+fills only when a reader requests a position, and the persistent bytecode-cache
+format is unchanged.

Source/JavaScriptCore/parser/SourceProvider.cpp

@@ -320,8 +320,12 @@ static unsigned lineEndFor(StringView text, const EncodedLineStarts& lineStarts,
 LineColumn LineStartTable::lineColumnForOffset(StringView text, unsigned offset)
 {
     Locker locker { m_lock };
-    auto line = EncodedLineStarts { ensureBuilt(text).bytes }.lineContaining(offset);
-    return { line.line0Based, offset - line.start };
+    // Syntax-selected stack positions bypass the per-instruction expression cache.
+    // Cache provider-relative coordinates so document offsets remain applied by the caller.
+    return m_cachedLineColumns.ensure(offset, [&] {
+        auto line = EncodedLineStarts { ensureBuilt(text).bytes }.lineContaining(offset);
+        return LineColumn { line.line0Based, offset - line.start };
+    }).iterator->value;
 }
 
 LineStartTable::PositionInfo LineStartTable::positionInfoForOffset(StringView text, unsigned offset)
@@ -365,4 +369,3 @@ LineColumn BuiltinsSourceProvider::lineColumnInTextForOffset(unsigned offset)
 }
 
 } // namespace JSC
-

Source/JavaScriptCore/parser/SourceProvider.h

@@ -40,6 +40,7 @@ WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
 #include <JavaScriptCore/SourceOrigin.h>
 #include <JavaScriptCore/SourceTaintedOrigin.h>
 #include <span>
+#include <wtf/HashMap.h>
 #include <wtf/Lock.h>
 #include <wtf/Noncopyable.h>
 #include <wtf/RefCountedFixedVector.h>
@@ -125,6 +126,8 @@ class LineStartTable {
 
     mutable Lock m_lock;
     LineStarts m_lineStarts WTF_GUARDED_BY_LOCK(m_lock);
+    using LineColumnMap = UncheckedKeyHashMap<uint64_t, LineColumn, WTF::IntHash<uint64_t>, WTF::UnsignedWithZeroKeyHashTraits<uint64_t>>;
+    LineColumnMap m_cachedLineColumns WTF_GUARDED_BY_LOCK(m_lock);
 };
 
 class JS_EXPORT_PRIVATE SourceProvider : public ThreadSafeRefCounted<SourceProvider> {
@@ -505,4 +508,4 @@ class SourceProviderBufferGuard {
     SourceProvider* m_sourceProvider { nullptr };
 };
 
-} // namespace JSC
+} // namespace JSC