Bytecode cache: compile-time layout asserts (replacing the layout dump); canonical NaN constants

.github/workflows/build-reusable.yml

@@ -718,33 +718,6 @@ jobs:
           while read -r name; do mv "dl/$name/bun-webkit.tar.gz" "out/$name.tar.gz"; done < artifacts.txt
           ls -la out
 
-      # A bytecode cache payload written on one platform is read in place on the others (bun build --compile
-      # cross-compiles), so the records it is made of must be laid out identically everywhere. Every Docker-built
-      # archive carries its layouts (Tools/Scripts/dump-bytecode-cache-layout.ts); any difference from linux-amd64, or a
-      # missing dump, fails the release. The one native build (windows-arm64-debug) has no dump and is not compared.
-      - name: Bytecode cache layouts agree across platforms
-        if: false # each image still writes bytecode-cache-layout.txt; the cross-platform comparison moves to its own fast job in a follow-up
-        run: |
-          set -euo pipefail
-          mkdir -p layouts
-          status=0
-          while read -r name; do
-            [ "$name" = bun-webkit-windows-arm64-debug ] && continue
-            if ! tar -xzf "out/$name.tar.gz" -O bun-webkit/bytecode-cache-layout.txt > "layouts/$name.txt"; then
-              echo "::error::$name has no bytecode-cache-layout.txt"
-              status=1
-            fi
-          done < artifacts.txt
-          for f in layouts/*.txt; do
-            if ! diff -u layouts/bun-webkit-linux-amd64.txt "$f" > "$f.diff"; then
-              echo "::error::bytecode cache record layouts in $(basename "$f" .txt) differ from linux-amd64"
-              head -50 "$f.diff"
-              status=1
-            fi
-          done
-          echo "$(ls layouts/*.txt | wc -l) platforms compared"
-          exit $status
-
       - name: Set release info
         id: release_info
         run: |

Dockerfile

@@ -308,7 +308,6 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     cd /webkitbuild && \
     cmake --build /webkitbuild --config $WEBKIT_RELEASE_TYPE --target "jsc" --target "testFFI" && \
     python3 /webkit/Tools/Scripts/check-classinfo-uniqueness.py $WEBKIT_OUT_DIR/bin/jsc && \
-    node --experimental-strip-types /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     cp -r $WEBKIT_OUT_DIR/lib/*.a /output/lib && \
     cp $WEBKIT_OUT_DIR/*.h /output/include && \
     cp -r $WEBKIT_OUT_DIR/bin /output/bin && \

Dockerfile.android

@@ -86,13 +86,6 @@ RUN mkdir -p /output/lib /output/include /output/include/JavaScriptCore /output/
 # etc.) at build time, so a host build is required first; the target build
 # points at it via --with-cross-build.
 # ───────────────────────────────────────────────────────────────────────────
-
-# Node — only used to run Tools/Scripts/dump-bytecode-cache-layout.ts after the build.
-ARG NODE_VERSION=24.16.0
-RUN wget -qO- "https://nodejs.org/dist/v${NODE_VERSION}/node-v${NODE_VERSION}-linux-$(uname -m | sed 's/x86_64/x64/;s/aarch64/arm64/').tar.xz" \
-      | tar -xJ -C /usr/local --strip-components=1 && \
-    node --version
-
 FROM base AS build_icu
 
 ARG MARCH_FLAG
@@ -214,7 +207,6 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     /webkit && \
     cmake --build /webkitbuild --config ${WEBKIT_RELEASE_TYPE} --target jsc --target testFFI && \
     python3 /webkit/Tools/Scripts/check-classinfo-uniqueness.py $WEBKIT_OUT_DIR/bin/jsc && \
-    node --experimental-strip-types /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     cp -r $WEBKIT_OUT_DIR/lib/*.a /output/lib && \
     cp $WEBKIT_OUT_DIR/*.h /output/include && \
     cp -r $WEBKIT_OUT_DIR/bin /output/bin && \

Dockerfile.freebsd

@@ -75,13 +75,6 @@ RUN mkdir -p /output/lib /output/include /output/include/JavaScriptCore /output/
 # ICU — cross-compiled. Same two-stage host/target build as Android: host
 # tools first, then --with-cross-build.
 # ───────────────────────────────────────────────────────────────────────────
-
-# Node — only used to run Tools/Scripts/dump-bytecode-cache-layout.ts after the build.
-ARG NODE_VERSION=24.16.0
-RUN wget -qO- "https://nodejs.org/dist/v${NODE_VERSION}/node-v${NODE_VERSION}-linux-$(uname -m | sed 's/x86_64/x64/;s/aarch64/arm64/').tar.xz" \
-      | tar -xJ -C /usr/local --strip-components=1 && \
-    node --version
-
 FROM base AS build_icu
 
 ARG MARCH_FLAG
@@ -206,7 +199,6 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     /webkit && \
     cmake --build /webkitbuild --config ${WEBKIT_RELEASE_TYPE} --target jsc --target testFFI && \
     python3 /webkit/Tools/Scripts/check-classinfo-uniqueness.py $WEBKIT_OUT_DIR/bin/jsc && \
-    node --experimental-strip-types /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     cp -r $WEBKIT_OUT_DIR/lib/*.a /output/lib && \
     cp $WEBKIT_OUT_DIR/*.h /output/include && \
     cp -r $WEBKIT_OUT_DIR/bin /output/bin && \

Dockerfile.macos

@@ -231,7 +231,6 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     /webkit && \
     cmake --build /webkitbuild --config ${WEBKIT_RELEASE_TYPE} --target jsc --target testFFI && \
     python3 /webkit/Tools/Scripts/check-classinfo-uniqueness.py $WEBKIT_OUT_DIR/bin/jsc && \
-    bun /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     # -L everywhere: WebKit's cmake stages the WTF/bmalloc framework headers
     # as *symlinks* into the source tree when the host filesystem supports
     # them. Copied verbatim they'd dangle outside this container (pointing at

Dockerfile.musl

@@ -101,7 +101,7 @@ ARG DEFAULT_CFLAGS
 ARG USE_MIMALLOC
 ARG USE_EXTERNAL_MIMALLOC
 
-RUN apk add --no-cache cpio curl file gnupg ninja nodejs ruby ruby-getoptlong unzip rsync perl python3 openssl-dev openssl linux-headers
+RUN apk add --no-cache cpio curl file gnupg ninja ruby ruby-getoptlong unzip rsync perl python3 openssl-dev openssl linux-headers
 
 ENV WEBKIT_OUT_DIR=/webkitbuild
 # These are unnecessary on musl
@@ -143,7 +143,6 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     cd /webkitbuild && \
     cmake --build /webkitbuild --config ${WEBKIT_RELEASE_TYPE} --target "jsc" --target "testFFI" && \
     python3 /webkit/Tools/Scripts/check-classinfo-uniqueness.py $WEBKIT_OUT_DIR/bin/jsc && \
-    node --experimental-strip-types /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     cp -r $WEBKIT_OUT_DIR/lib/*.a /output/lib && \
     cp $WEBKIT_OUT_DIR/*.h /output/include && \
     cp -r $WEBKIT_OUT_DIR/bin /output/bin && \

Dockerfile.windows

@@ -325,7 +325,6 @@ ARG USE_MIMALLOC
 ARG USE_EXTERNAL_MIMALLOC
 
 COPY --from=build_icu /icu-out /icu-out
-COPY --from=build_icu /usr/local/bin/node /usr/local/bin/node
 COPY . /webkit
 WORKDIR /webkit
 
@@ -412,11 +411,9 @@ RUN --mount=type=tmpfs,target=/webkitbuild \
     "-DCMAKE_CXX_FLAGS_RELEASE=/O2 /Ob2 /DNDEBUG ${LTO_FLAG}" \
     "-DCMAKE_C_FLAGS_DEBUG=/FS /O0 /Ob0" \
     "-DCMAKE_CXX_FLAGS_DEBUG=/FS /O0 /Ob0" \
-    -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
     -G Ninja \
     /webkit && \
     cmake --build /webkitbuild --config ${WEBKIT_RELEASE_TYPE} --target jsc --target testFFI && \
-    mkdir -p /output && node --experimental-strip-types /webkit/Tools/Scripts/dump-bytecode-cache-layout.ts /webkitbuild > /output/bytecode-cache-layout.txt && \
     \
     mkdir -p /output/lib /output/include/JavaScriptCore /output/include/wtf /output/include/bmalloc && \
     cp -rL $WEBKIT_OUT_DIR/lib/* /output/lib/ && \

Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

@@ -1694,6 +1694,10 @@ RegisterID* BytecodeGenerator::addConstantValue(JSValue v, SourceCodeRepresentat
 
     if (sourceCodeRepresentation == SourceCodeRepresentation::Double && v.isInt32())
         v = jsDoubleNumber(v.asNumber());
+    // A NaN the parser folded (0 / 0) has whatever bits this CPU's arithmetic produces (the sign differs between x86 and
+    // ARM); the constant, and so the bytecode, should not depend on that.
+    if (v.isDouble() && std::isnan(v.asDouble()))
+        v = jsNaN();
     EncodedJSValueWithRepresentation valueMapKey { JSValue::encode(v), sourceCodeRepresentation };
     JSValueMap::AddResult result = m_jsValueMap.add(valueMapKey, m_nextConstantOffset);
     if (result.isNewEntry) {