wip: experiment with windows bazel v8 build

ci: enable the Windows Bazel workflow path
2026-03-28 19:16:30 +03:00 · 2026-03-27 19:34:32 -07:00 · 2026-03-27 19:34:32 -07:00
17 changed files with 761 additions and 56 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -20,9 +20,6 @@ common:windows --host_platform=//:local_windows
 common --@rules_cc//cc/toolchains/args/archiver_flags:use_libtool_on_macos=False
 common --@llvm//config:experimental_stub_libgcc_s

-# We need to use the sh toolchain on windows so we don't send host bash paths to the linux executor.
-common:windows --@rules_rust//rust/settings:experimental_use_sh_toolchain_for_bootstrap_process_wrapper
-
 # TODO(zbarsky): rules_rust doesn't implement this flag properly with remote exec...
 # common --@rules_rust//rust/settings:pipelined_compilation

--- a/.github/actions/setup-bazel-ci/action.yml
+++ b/.github/actions/setup-bazel-ci/action.yml
@@ -57,5 +57,11 @@ runs:
      if: runner.os == 'Windows'
      shell: pwsh
      run: |
-        # Use a very short path to reduce argv/path length issues.
-        "BAZEL_OUTPUT_USER_ROOT=C:\" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+        # Use a very short path to reduce argv/path length issues, but avoid the
+        # drive root because some Windows test launchers mis-handle MANIFEST paths there.
+        "BAZEL_OUTPUT_USER_ROOT=D:\b" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+
+    - name: Enable Git long paths (Windows)
+      if: runner.os == 'Windows'
+      shell: pwsh
+      run: git config --global core.longpaths true
--- a/.github/workflows/bazel.yml
+++ b/.github/workflows/bazel.yml
@@ -17,6 +17,7 @@ concurrency:
  cancel-in-progress: ${{ github.ref_name != 'main' }}
 jobs:
  test:
+    timeout-minutes: 120
    strategy:
      fail-fast: false
      matrix:
@@ -39,9 +40,9 @@ jobs:
          # - os: ubuntu-24.04-arm
          #   target: aarch64-unknown-linux-gnu

-          # TODO: Enable Windows once we fix the toolchain issues there.
-          #- os: windows-latest
-          #  target: x86_64-pc-windows-gnullvm
+          # Windows
+          - os: windows-latest
+            target: x86_64-pc-windows-gnullvm
    runs-on: ${{ matrix.os }}

    # Configure a human readable name for each job
@@ -67,8 +68,14 @@ jobs:
          BUILDBUDDY_API_KEY: ${{ secrets.BUILDBUDDY_API_KEY }}
        shell: bash
        run: |
-          # Keep V8 out of the ordinary Bazel CI path. Only the dedicated
-          # canary and release workflows should build `third_party/v8`.
+          bazel_targets=(
+            //...
+            # Keep standalone V8 library targets out of the ordinary Bazel CI
+            # path. V8 consumers under `//codex-rs/...` still participate
+            # transitively through `//...`.
+            -//third_party/v8:all
+          )
+
          ./.github/scripts/run-bazel-ci.sh \
            --print-failed-test-logs \
            --use-node-test-env \
@@ -77,8 +84,7 @@ jobs:
            --test_verbose_timeout_warnings \
            --build_metadata=COMMIT_SHA=${GITHUB_SHA} \
            -- \
-            //... \
-            -//third_party/v8:all
+            "${bazel_targets[@]}"

      # Save bazel repository cache explicitly; make non-fatal so cache uploading
      # never fails the overall job. Only save when key wasn't hit.
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -3,6 +3,25 @@ module(name = "codex")
 bazel_dep(name = "bazel_skylib", version = "1.8.2")
 bazel_dep(name = "platforms", version = "1.0.0")
 bazel_dep(name = "llvm", version = "0.6.8")
+# The upstream LLVM archive contains a few unix-only symlink entries and is
+# missing a couple of MinGW compatibility archives that windows-gnullvm needs
+# during extraction and linking, so patch it until upstream grows native support.
+single_version_override(
+    module_name = "llvm",
+    patch_strip = 1,
+    patches = [
+        "//patches:llvm_windows_symlink_extract.patch",
+    ],
+)
+# Abseil picks a MinGW pthread TLS path that does not match our hermetic
+# windows-gnullvm toolchain; force it onto the portable C++11 thread-local path.
+single_version_override(
+    module_name = "abseil-cpp",
+    patch_strip = 1,
+    patches = [
+        "//patches:abseil_windows_gnullvm_thread_identity.patch",
+    ],
+)

 register_toolchains("@llvm//toolchain:all")

@@ -44,8 +63,28 @@ bazel_dep(name = "apple_support", version = "2.1.0")
 bazel_dep(name = "rules_cc", version = "0.2.16")
 bazel_dep(name = "rules_platform", version = "0.1.0")
 bazel_dep(name = "rules_rs", version = "0.0.43")
+# `rules_rs` 0.0.43 does not model `windows-gnullvm` as a distinct Windows exec
+# platform, so patch it until upstream grows that support for both x86_64 and
+# aarch64.
+single_version_override(
+    module_name = "rules_rs",
+    patch_strip = 1,
+    patches = [
+        "//patches:rules_rs_windows_gnullvm_exec.patch",
+    ],
+    version = "0.0.43",
+)

 rules_rust = use_extension("@rules_rs//rs/experimental:rules_rust.bzl", "rules_rust")
+# Build-script probe binaries inherit CFLAGS/CXXFLAGS from Bazel's C++
+# toolchain. On `windows-gnullvm`, llvm-mingw does not ship
+# `libssp_nonshared`, so strip the forwarded stack-protector flags there.
+rules_rust.patch(
+    patches = [
+        "//patches:rules_rust_windows_gnullvm_build_script.patch",
+    ],
+    strip = 1,
+)
 use_repo(rules_rust, "rules_rust")

 toolchains = use_extension("@rules_rs//rs/experimental/toolchains:module_extension.bzl", "toolchains")
@@ -65,10 +104,15 @@ crate.from_cargo(
        "aarch64-unknown-linux-gnu",
        "aarch64-unknown-linux-musl",
        "aarch64-apple-darwin",
+        # Keep both Windows ABIs in the generated Cargo metadata: the V8
+        # experiment still consumes release assets that only exist under the
+        # MSVC names while targeting the GNU toolchain.
+        "aarch64-pc-windows-msvc",
        "aarch64-pc-windows-gnullvm",
        "x86_64-unknown-linux-gnu",
        "x86_64-unknown-linux-musl",
        "x86_64-apple-darwin",
+        "x86_64-pc-windows-msvc",
        "x86_64-pc-windows-gnullvm",
    ],
    use_experimental_platforms = True,
--- a/MODULE.bazel.lock
+++ b/MODULE.bazel.lock
@@ -1576,15 +1576,19 @@
    },
    "@@rules_rs+//rs/experimental/toolchains:module_extension.bzl%toolchains": {
      "cargo-1.93.0-aarch64-apple-darwin.tar.xz": "6443909350322ad07f09bb5edfd9ff29268e6fe88c7d78bfba7a5e254248dc25",
+      "cargo-1.93.0-aarch64-pc-windows-gnullvm.tar.xz": "387832b989c8eb96c9ebd66402a87962167633bc6d91a49ffb8c7903c45f3476",
      "cargo-1.93.0-aarch64-pc-windows-msvc.tar.xz": "155bff7a16aa7054e7ed7c3a82e362d4b302b3882d751b823e06ff63ae3f103d",
      "cargo-1.93.0-aarch64-unknown-linux-gnu.tar.xz": "5998940b8b97286bb67facb1a85535eeb3d4d7a61e36a85e386e5c0c5cfe5266",
      "cargo-1.93.0-x86_64-apple-darwin.tar.xz": "95a47c5ed797c35419908f04188d8b7de09946e71073c4b72632b16f5b10dfae",
+      "cargo-1.93.0-x86_64-pc-windows-gnullvm.tar.xz": "f19766837559f90476508140cb95cc708220012ec00a854fa9f99187b1f246b6",
      "cargo-1.93.0-x86_64-pc-windows-msvc.tar.xz": "e59c5e2baa9ec17261f2cda6676ebf7b68b21a860e3f7451c4d964728951da75",
      "cargo-1.93.0-x86_64-unknown-linux-gnu.tar.xz": "c23de3ae709ff33eed5e4ae59d1f9bcd75fa4dbaa9fb92f7b06bfb534b8db880",
      "clippy-1.93.0-aarch64-apple-darwin.tar.xz": "0b6e943a8d12be0e68575acf59c9ea102daf795055fcbbf862b0bfd35ec40039",
+      "clippy-1.93.0-aarch64-pc-windows-gnullvm.tar.xz": "296949f49be2de77ce9d1c5023a5f0a58e28e329eec03642a3da0e175a67beeb",
      "clippy-1.93.0-aarch64-pc-windows-msvc.tar.xz": "07bcf2edb88cdf5ead2f02e4a8493e9b0ef935a31253fac6f9f3378d8023f113",
      "clippy-1.93.0-aarch64-unknown-linux-gnu.tar.xz": "872ae6d68d625946d281b91d928332e6b74f6ab269b6af842338df4338805a60",
      "clippy-1.93.0-x86_64-apple-darwin.tar.xz": "e6d0b1afb9607c14a1172d09ee194a032bbb3e48af913d55c5a473e0559eddde",
+      "clippy-1.93.0-x86_64-pc-windows-gnullvm.tar.xz": "b6f1f7264ed6943c59dedfb9531fbadcc3c0fcf273c940a63d58898b14a1060f",
      "clippy-1.93.0-x86_64-pc-windows-msvc.tar.xz": "25fb103390bf392980b4689ac09b2ec2ab4beefb7022a983215b613ad05eab57",
      "clippy-1.93.0-x86_64-unknown-linux-gnu.tar.xz": "793108977514b15c0f45ade28ae35c58b05370cb0f22e89bd98fdfa61eabf55d",
      "rust-std-1.93.0-aarch64-apple-darwin.tar.xz": "8603c63715349636ed85b4fe716c4e827a727918c840e54aff5b243cedadf19b",
@@ -1653,15 +1657,19 @@
      "rust-std-1.93.0-x86_64-unknown-none.tar.xz": "01dcca7ae4b7e82fbfa399adb5e160afaa13143e5a17e1e0737c38cf07365fb3",
      "rust-std-1.93.0-x86_64-unknown-uefi.tar.xz": "ec4e439d9485ce752b56999e8e41ed82373fc833a005cf2531c6f7ef7e785392",
      "rustc-1.93.0-aarch64-apple-darwin.tar.xz": "092be03c02b44c405dab1232541c84f32b2d9e8295747568c3d531dd137221dc",
+      "rustc-1.93.0-aarch64-pc-windows-gnullvm.tar.xz": "d3bc0cdaf157e20b1f23e510b5e3c4c6e9117d08f5284c04dee60aecff1bc851",
      "rustc-1.93.0-aarch64-pc-windows-msvc.tar.xz": "a3ac1a8e411de8470f71b366f89d187718c431526912b181692ed0a18c56c7ad",
      "rustc-1.93.0-aarch64-unknown-linux-gnu.tar.xz": "1a9045695892ec08d8e9751bf7cf7db71fe27a6202dd12ce13aca48d0602dbde",
      "rustc-1.93.0-x86_64-apple-darwin.tar.xz": "594bb293f0a4f444656cf8dec2149fcb979c606260efee9e09bcf8c9c6ed6ae7",
+      "rustc-1.93.0-x86_64-pc-windows-gnullvm.tar.xz": "0cdaa8de66f5ce21d1ea73917efc5c64f408bda49f678ddde19465ced9d5ec63",
      "rustc-1.93.0-x86_64-pc-windows-msvc.tar.xz": "fa17677eee0d83eb055b309953184bf87ba634923d8897f860cda65d55c6e350",
      "rustc-1.93.0-x86_64-unknown-linux-gnu.tar.xz": "00c6e6740ea6a795e33568cd7514855d58408a1180cd820284a7bbf7c46af715",
      "rustfmt-1.93.0-aarch64-apple-darwin.tar.xz": "0dd1faedf0768ef362f4aae4424b34e8266f2b9cf5e76ea4fcaf780220b363a0",
+      "rustfmt-1.93.0-aarch64-pc-windows-gnullvm.tar.xz": "5888827e7fbd7d59930870b4856fce8d6d8fca5e02f6535f8ae3d7ad0ccf2d4a",
      "rustfmt-1.93.0-aarch64-pc-windows-msvc.tar.xz": "24eed108489567133bbfe40c8eacda1567be55fae4c526911b39eb33eb27a6cb",
      "rustfmt-1.93.0-aarch64-unknown-linux-gnu.tar.xz": "92e1acb45ae642136258b4dabb39302af2d53c83e56ebd5858bc969f9e5c141a",
      "rustfmt-1.93.0-x86_64-apple-darwin.tar.xz": "c8453b4c5758eb39423042ffa9c23ed6128cbed2b15b581e5e1192c9cc0b1d4e",
+      "rustfmt-1.93.0-x86_64-pc-windows-gnullvm.tar.xz": "47167e9e78db9be4503a060dee02f4df2cda252da32175dbf44331f965a747b9",
      "rustfmt-1.93.0-x86_64-pc-windows-msvc.tar.xz": "5becc7c2dba4b9ab5199012cad30829235a7f7fb5d85a238697e8f0e44cbd9af",
      "rustfmt-1.93.0-x86_64-unknown-linux-gnu.tar.xz": "7f81f6c17d11a7fda5b4e1b111942fb3b23d30dcec767e13e340ebfb762a5e33"
    }
--- a/defs.bzl
+++ b/defs.bzl
@@ -13,6 +13,18 @@ PLATFORMS = [
    "windows_arm64",
 ]

+# The Bazel-built windows-gnullvm binaries that pull in V8 need a larger PE
+# stack reserve than the default linker setting. Thread the flag through the
+# executable and test entry points so the final linked artifacts behave the same
+# in normal builds and under `bazel test`.
+WINDOWS_GNULLVM_RUSTC_STACK_FLAGS = select({
+    "@rules_rs//rs/experimental/platforms/constraints:windows_gnullvm": [
+        "-C",
+        "link-arg=-Wl,--stack,8388608",
+    ],
+    "//conditions:default": [],
+})
+
 def multiplatform_binaries(name, platforms = PLATFORMS):
    for platform in platforms:
        platform_data(
@@ -224,7 +236,7 @@ def codex_rust_crate(
            crate_root = main,
            deps = all_crate_deps() + maybe_deps + deps_extra,
            edition = crate_edition,
-            rustc_flags = rustc_flags_extra,
+            rustc_flags = rustc_flags_extra + WINDOWS_GNULLVM_RUSTC_STACK_FLAGS,
            srcs = native.glob(["src/**/*.rs"]),
            visibility = ["//visibility:public"],
        )
@@ -252,7 +264,7 @@ def codex_rust_crate(
            # Bazel has emitted both `codex-rs/<crate>/...` and
            # `../codex-rs/<crate>/...` paths for `file!()`. Strip either
            # prefix so Insta records Cargo-like metadata such as `core/tests/...`.
-            rustc_flags = rustc_flags_extra + [
+            rustc_flags = rustc_flags_extra + WINDOWS_GNULLVM_RUSTC_STACK_FLAGS + [
                "--remap-path-prefix=../codex-rs=",
                "--remap-path-prefix=codex-rs=",
            ],
--- a/patches/BUILD.bazel
+++ b/patches/BUILD.bazel
@@ -1,5 +1,9 @@
 exports_files([
+    "abseil_windows_gnullvm_thread_identity.patch",
    "aws-lc-sys_memcmp_check.patch",
+    "llvm_windows_symlink_extract.patch",
+    "rules_rust_windows_gnullvm_build_script.patch",
+    "rules_rs_windows_gnullvm_exec.patch",
    "rusty_v8_prebuilt_out_dir.patch",
    "v8_bazel_rules.patch",
    "v8_module_deps.patch",
--- a/patches/abseil_windows_gnullvm_thread_identity.patch
+++ b/patches/abseil_windows_gnullvm_thread_identity.patch
@@ -0,0 +1,16 @@
+# What: avoid MinGW pthread TLS linkage in Abseil thread identity selection.
+# Scope: one MinGW-specific preprocessor branch in Abseil's internal
+# thread-identity mode selection; no other Abseil behavior changes.
+
+diff --git a/absl/base/internal/thread_identity.h b/absl/base/internal/thread_identity.h
+--- a/absl/base/internal/thread_identity.h
+++ b/absl/base/internal/thread_identity.h
+@@ -217,6 +217,8 @@
+ #error ABSL_THREAD_IDENTITY_MODE cannot be directly set
+ #elif defined(ABSL_FORCE_THREAD_IDENTITY_MODE)
+ #define ABSL_THREAD_IDENTITY_MODE ABSL_FORCE_THREAD_IDENTITY_MODE
+#elif defined(__MINGW32__)
+#define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
+ #elif defined(_WIN32) && !defined(__MINGW32__)
+ #define ABSL_THREAD_IDENTITY_MODE ABSL_THREAD_IDENTITY_MODE_USE_CPP11
+ #elif defined(__APPLE__) && defined(ABSL_HAVE_THREAD_LOCAL)
--- a/patches/llvm_windows_symlink_extract.patch
+++ b/patches/llvm_windows_symlink_extract.patch
@@ -0,0 +1,64 @@
+diff --git a/extensions/llvm_source.bzl b/extensions/llvm_source.bzl
+index 89dcf81..cf27c92 100644
+--- a/extensions/llvm_source.bzl
+++ b/extensions/llvm_source.bzl
+@@ -83,6 +83,13 @@ def _llvm_source_archive_excludes():
+         "offload",
+         "libc/docs",
+         "libc/utils/gn",
+        # These entries are unix symlinks in the upstream source tarball.
+        # Windows tar.exe cannot materialize them during repository extraction,
+        # but nothing in our Bazel usage needs the symlink entrypoints.
+        "llvm/utils/mlgo-utils/extract_ir.py",
+        "llvm/utils/mlgo-utils/make_corpus.py",
+        "llvm/utils/mlgo-utils/combine_training_corpus.py",
+        "llvm/docs/_themes/llvm-theme",
+     ]
+ 
+     test_docs_subprojects = [
+diff --git a/runtimes/mingw/BUILD.bazel b/runtimes/mingw/BUILD.bazel
+index ebd99db..9eb5d5b 100644
+--- a/runtimes/mingw/BUILD.bazel
+++ b/runtimes/mingw/BUILD.bazel
+@@ -334,6 +334,30 @@ stub_library(
+     name = "stdc++",
+ )
+ 
+# Clang may inject -lssp and -lssp_nonshared for windows-gnu links.
+# Provide compatibility archives in the MinGW runtime search directory.
+stub_library(
+    name = "ssp",
+)
+
+stub_library(
+    name = "ssp_nonshared",
+)
+
+# Prebuilt MSVC archives can carry /DEFAULTLIB:libcmt.lib and
+# /DEFAULTLIB:oldnames.lib directives. Provide MinGW-compatible stand-ins so
+# lld can satisfy the lookup under windows-gnullvm.
+stub_library(
+    name = "libcmt",
+)
+
+copy_file(
+    name = "oldnames",
+    src = ":moldname",
+    out = "liboldnames.a",
+    visibility = ["//visibility:public"],
+)
+
+ copy_to_directory(
+     name = "mingw_crt_library_search_directory",
+     srcs = [
+@@ -344,6 +364,10 @@ copy_to_directory(
+         ":moldname",
+        ":oldnames",
+         ":pthread",
+         ":stdc++",
+        ":ssp",
+        ":ssp_nonshared",
+        ":libcmt",
+         ":ucrt",
+         ":ucrtbase",
+         ":ucrtbased",
--- a/patches/rules_rs_windows_gnullvm_exec.patch
+++ b/patches/rules_rs_windows_gnullvm_exec.patch
@@ -0,0 +1,151 @@
+# What: teach `rules_rs` that `windows-gnullvm` is a distinct Windows exec ABI.
+# Scope: experimental platform/toolchain naming only; no Cargo target changes.
+
+diff --git a/rs/experimental/platforms/triples.bzl b/rs/experimental/platforms/triples.bzl
+index 3ca3bb1..dd15656 100644
+--- a/rs/experimental/platforms/triples.bzl
+++ b/rs/experimental/platforms/triples.bzl
+@@ -30,7 +30,9 @@ SUPPORTED_EXEC_TRIPLES = [
+     "x86_64-unknown-linux-gnu",
+     "aarch64-unknown-linux-gnu",
+     "x86_64-pc-windows-msvc",
+    "x86_64-pc-windows-gnullvm",
+     "aarch64-pc-windows-msvc",
+    "aarch64-pc-windows-gnullvm",
+     "x86_64-apple-darwin",
+     "aarch64-apple-darwin",
+ ]
+diff --git a/rs/experimental/toolchains/declare_rustc_toolchains.bzl b/rs/experimental/toolchains/declare_rustc_toolchains.bzl
+index b9a0ce1..67e491c 100644
+--- a/rs/experimental/toolchains/declare_rustc_toolchains.bzl
+++ b/rs/experimental/toolchains/declare_rustc_toolchains.bzl
+@@ -10,6 +10,11 @@ def _channel(version):
+         return "beta"
+     return "stable"
+ 
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
+
+ def declare_rustc_toolchains(
+         *,
+         version,
+@@ -23,15 +28,14 @@ def declare_rustc_toolchains(
+ 
+     for triple in execs:
+         exec_triple = _parse_triple(triple)
+-        triple_suffix = exec_triple.system + "_" + exec_triple.arch
+        triple_suffix = _exec_triple_suffix(exec_triple)
+ 
+         rustc_repo_label = "@rustc_{}_{}//:".format(triple_suffix, version_key)
+         cargo_repo_label = "@cargo_{}_{}//:".format(triple_suffix, version_key)
+         clippy_repo_label = "@clippy_{}_{}//:".format(triple_suffix, version_key)
+ 
+-        rust_toolchain_name = "{}_{}_{}_rust_toolchain".format(
+-            exec_triple.system,
+-            exec_triple.arch,
+        rust_toolchain_name = "{}_{}_rust_toolchain".format(
+            triple_suffix,
+             version_key,
+         )
+ 
+@@ -90,11 +94,8 @@ def declare_rustc_toolchains(
+             target_key = sanitize_triple(target_triple)
+ 
+             native.toolchain(
+-                name = "{}_{}_to_{}_{}".format(exec_triple.system, exec_triple.arch, target_key, version_key),
+-                exec_compatible_with = [
+-                    "@platforms//os:" + exec_triple.system,
+-                    "@platforms//cpu:" + exec_triple.arch,
+-                ],
+                name = "{}_to_{}_{}".format(triple_suffix, target_key, version_key),
+                exec_compatible_with = triple_to_constraint_set(triple),
+                 target_compatible_with = triple_to_constraint_set(target_triple),
+                 target_settings = [
+                     "@rules_rust//rust/toolchain/channel:" + channel,
+diff --git a/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl b/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
+index a219209..ecb6b05 100644
+--- a/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
+++ b/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
+@@ -1,8 +1,13 @@
+ load("@rules_rust//rust:toolchain.bzl", "rustfmt_toolchain")
+ load("@rules_rust//rust/platform:triple.bzl", _parse_triple = "triple")
+-load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES")
+load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES", "triple_to_constraint_set")
+ load("//rs/experimental/toolchains:toolchain_utils.bzl", "sanitize_version")
+ 
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
+
+ def _channel(version):
+     if version.startswith("nightly"):
+         return "nightly"
+@@ -22,14 +27,13 @@ def declare_rustfmt_toolchains(
+ 
+     for triple in execs:
+         exec_triple = _parse_triple(triple)
+-        triple_suffix = exec_triple.system + "_" + exec_triple.arch
+        triple_suffix = _exec_triple_suffix(exec_triple)
+ 
+         rustc_repo_label = "@rustc_{}_{}//:".format(triple_suffix, version_key)
+         rustfmt_repo_label = "@rustfmt_{}_{}//:".format(triple_suffix, rustfmt_version_key)
+ 
+-        rustfmt_toolchain_name = "{}_{}_{}_rustfmt_toolchain".format(
+-            exec_triple.system,
+-            exec_triple.arch,
+        rustfmt_toolchain_name = "{}_{}_rustfmt_toolchain".format(
+            triple_suffix,
+             version_key,
+         )
+ 
+@@ -43,11 +47,8 @@ def declare_rustfmt_toolchains(
+         )
+ 
+         native.toolchain(
+-            name = "{}_{}_rustfmt_{}".format(exec_triple.system, exec_triple.arch, version_key),
+-            exec_compatible_with = [
+-                "@platforms//os:" + exec_triple.system,
+-                "@platforms//cpu:" + exec_triple.arch,
+-            ],
+            name = "{}_rustfmt_{}".format(triple_suffix, version_key),
+            exec_compatible_with = triple_to_constraint_set(triple),
+             target_compatible_with = [],
+             target_settings = [
+                 "@rules_rust//rust/toolchain/channel:" + channel,
+diff --git a/rs/experimental/toolchains/module_extension.bzl b/rs/experimental/toolchains/module_extension.bzl
+index 7bb0205..ace556b 100644
+--- a/rs/experimental/toolchains/module_extension.bzl
+++ b/rs/experimental/toolchains/module_extension.bzl
+@@ -37,6 +37,11 @@ def _normalize_arch_name(arch):
+         return "aarch64"
+     return arch
+ 
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
+
+ def _sanitize_path_fragment(path):
+     return path.replace("/", "_").replace(":", "_")
+ 
+@@ -181,7 +186,7 @@ def _toolchains_impl(mctx):
+         for triple in SUPPORTED_EXEC_TRIPLES:
+             exec_triple = _parse_triple(triple)
+ 
+-            triple_suffix = exec_triple.system + "_" + exec_triple.arch
+            triple_suffix = _exec_triple_suffix(exec_triple)
+             rustc_name = "rustc_{}_{}".format(triple_suffix, version_key)
+ 
+             rustc_repository(
+@@ -230,7 +235,7 @@ def _toolchains_impl(mctx):
+ 
+         for triple in SUPPORTED_EXEC_TRIPLES:
+             exec_triple = _parse_triple(triple)
+-            triple_suffix = exec_triple.system + "_" + exec_triple.arch
+            triple_suffix = _exec_triple_suffix(exec_triple)
+ 
+             rustfmt_repository(
+                 name = "rustfmt_{}_{}".format(triple_suffix, version_key),
--- a/patches/rules_rust_windows_gnullvm_build_script.patch
+++ b/patches/rules_rust_windows_gnullvm_build_script.patch
@@ -0,0 +1,38 @@
+diff --git a/cargo/private/cargo_build_script.bzl b/cargo/private/cargo_build_script.bzl
+--- a/cargo/private/cargo_build_script.bzl
+++ b/cargo/private/cargo_build_script.bzl
+@@ -120,6 +120,25 @@
+     executable = True,
+ )
+ 
+def _strip_stack_protector_for_windows_llvm_mingw(toolchain, args):
+    """Drop stack protector flags unsupported by llvm-mingw build-script probes."""
+    if "windows-gnullvm" not in toolchain.target_flag_value:
+        return args
+
+    uses_llvm_mingw = False
+    for arg in args:
+        if "mingw-w64-" in arg:
+            uses_llvm_mingw = True
+            break
+
+    if not uses_llvm_mingw:
+        return args
+
+    # llvm-mingw does not ship libssp_nonshared, so forwarding stack-protector
+    # flags through CFLAGS/CXXFLAGS breaks build.rs probe binaries compiled via
+    # cc-rs.
+    return [arg for arg in args if not arg.startswith("-fstack-protector")]
+
+ def get_cc_compile_args_and_env(cc_toolchain, feature_configuration):
+     """Gather cc environment variables from the given `cc_toolchain`
+ 
+@@ -503,6 +522,8 @@
+         if not env["AR"]:
+             env["AR"] = cc_toolchain.ar_executable
+ 
+        cc_c_args = _strip_stack_protector_for_windows_llvm_mingw(toolchain, cc_c_args)
+        cc_cxx_args = _strip_stack_protector_for_windows_llvm_mingw(toolchain, cc_cxx_args)
+         # Populate CFLAGS and CXXFLAGS that cc-rs relies on when building from source, in particular
+         # to determine the deployment target when building for apple platforms (`macosx-version-min`
+         # for example, itself derived from the `macos_minimum_os` Bazel argument).
--- a/patches/rusty_v8_prebuilt_out_dir.patch
+++ b/patches/rusty_v8_prebuilt_out_dir.patch
@@ -1,5 +1,27 @@
+# What: make `rusty_v8` accept Bazel-provided archives and bindings for the
+# windows-gnullvm experiment.
+# Scope: `rusty_v8` build.rs only; no V8 source or Bazel rule changes.
+
 --- a/build.rs
 +++ b/build.rs
+@@ -543,10 +543,15 @@
+ }
+ 
+ fn static_lib_name(suffix: &str) -> String {
+-  let target_os = env::var("CARGO_CFG_TARGET_OS").unwrap();
+-  if target_os == "windows" {
+  let target = env::var("TARGET").unwrap();
+  let target_os = env::var("CARGO_CFG_TARGET_OS").unwrap();
+  if target.contains("windows-gnullvm") {
+    // rustc looks for GNU-style archive names when bundling `-lstatic` on the
+    // gnullvm targets, even though the prebuilt release is a COFF `.lib`.
+    format!("librusty_v8{suffix}.a")
+  } else if target_os == "windows" {
+     format!("rusty_v8{suffix}.lib")
+   } else {
+     format!("librusty_v8{suffix}.a")
+   }
+ }
@@ -577,7 +577,23 @@
   path
 }
--- a/patches/v8_bazel_rules.patch
+++ b/patches/v8_bazel_rules.patch
@@ -29,11 +29,17 @@ index 9648e4a..88efd41 100644
             "@v8//bazel/config:is_gcc": [
                 "-Wno-extra",
                 "-Wno-array-bounds",
-@@ -155,7 +149,12 @@ def _default_args():
-             "@v8//bazel/config:is_windows": [
-                 "/std:c++20",
-             ],
+@@ -155,7 +149,15 @@ def _default_args():
+-            "@v8//bazel/config:is_windows": [
+-                "/std:c++20",
+-            ],
 -            "//conditions:default": [],
+            "@v8//bazel/config:is_windows": [
+                "-Wno-invalid-offsetof",
+                "-Wno-deprecated-this-capture",
+                "-Wno-deprecated-declarations",
+                "-std=c++20",
+            ],
 +            "//conditions:default": [
 +                "-Wno-invalid-offsetof",
 +                "-Wno-deprecated-this-capture",
@@ -43,8 +49,14 @@ index 9648e4a..88efd41 100644
         }) + select({
             "@v8//bazel/config:is_gcc_fastbuild": [
                 # Non-debug builds without optimizations fail because
-@@ -184,7 +183,7 @@ def _default_args():
-                 "Advapi32.lib",
+@@ -180,10 +179,10 @@ def _default_args():
+             "@v8//bazel/config:is_windows": [
+-                "Winmm.lib",
+-                "DbgHelp.lib",
+-                "Advapi32.lib",
+                "-lwinmm",
+                "-ldbghelp",
+                "-ladvapi32",
             ],
             "@v8//bazel/config:is_macos": ["-pthread"],
 -            "//conditions:default": ["-Wl,--no-as-needed -ldl -latomic -pthread"],
@@ -225,3 +237,39 @@ index 5fda2f4..381386c 100644
 # Copyright 2021 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+@@ -16,10 +18,7 @@ cc_library(
+     ]),
+     copts = select({
+         "@platforms//os:windows": [
+-            "/wd4005",  # Macro redefinition.
+-            "/wd4068",  # Unknown pragmas.
+-            "/wd4267",  # Conversion from size_t on 64-bits.
+-            "/utf-8",  # ICU source files are in UTF-8.
+            "-Wno-deprecated-declarations",
+         ],
+         "//conditions:default": [
+             "-Wno-deprecated-declarations",
+@@ -65,10 +64,7 @@ cc_library(
+     ]),
+     copts = select({
+         "@platforms//os:windows": [
+-            "/wd4005",  # Macro redefinition.
+-            "/wd4068",  # Unknown pragmas.
+-            "/wd4267",  # Conversion from size_t on 64-bits.
+-            "/utf-8",  # ICU source files are in UTF-8.
+            "-Wno-deprecated-declarations",
+         ],
+         "//conditions:default": [
+             "-Wno-deprecated-declarations",
+@@ -93,10 +89,7 @@ cc_library(
+     ]),
+     copts = select({
+         "@platforms//os:windows": [
+-            "/wd4005",  # Macro redefinition.
+-            "/wd4068",  # Unknown pragmas.
+-            "/wd4267",  # Conversion from size_t on 64-bits.
+-            "/utf-8",  # ICU source files are in UTF-8.
+            "-Wno-deprecated-declarations",
+         ],
+         "//conditions:default": [],
+     }),
--- a/patches/v8_module_deps.patch
+++ b/patches/v8_module_deps.patch
@@ -62,7 +62,7 @@ diff --git a/orig/v8-14.6.202.11/MODULE.bazel b/mod/v8-14.6.202.11/MODULE.bazel
 +    commit = "3d2de1816307bac63c16a297e8c4dc501b4076df",
 +    remote = "https://chromium.googlesource.com/external/github.com/Maratyszcza/FP16.git",
 +)
-
+ 
 pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
 pip.parse(
@@ -22,171 +72,3 @@
@@ -241,16 +241,29 @@ diff --git a/orig/v8-14.6.202.11/bazel/highway.patch b/mod/v8-14.6.202.11/bazel/
 new file mode 100644
 --- /dev/null
 +++ b/mod/v8-14.6.202.11/bazel/highway.patch
-@@ -0,0 +1,12 @@
+@@ -0,0 +1,25 @@
 +diff --git a/BUILD b/BUILD
 +--- a/BUILD
 ++++ b/BUILD
 +@@ -2,7 +2,7 @@
 + load("@bazel_skylib//lib:selects.bzl", "selects")
 + load("@rules_license//rules:license.bzl", "license")
-+
+ 
 +-load("@rules_cc//cc:defs.bzl", "cc_test")
 ++load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_test")
 + # Placeholder#2 for Guitar, do not remove
-+
+ 
 + package(
+@@ -134,11 +134,7 @@ COPTS = select({
+     ],
+ })
+ 
+-DEFINES = select({
+-    ":compiler_msvc": ["HWY_SHARED_DEFINE"],
+-    ":compiler_clangcl": ["HWY_SHARED_DEFINE"],
+-    "//conditions:default": [],
+-})
++DEFINES = []
+ 
+ # Unused on Bazel builds, where this is not defined/known; Copybara replaces
+ # usages with an empty list.
--- a/patches/v8_source_portability.patch
+++ b/patches/v8_source_portability.patch
@@ -2,7 +2,28 @@
 # Scope: minimal source-level portability fixes only, such as libexecinfo guards,
 # weak glibc symbol handling, and warning annotations; no dependency
 # include-path rewrites or intentional V8 feature changes.
-
+diff --git a/orig/v8-14.6.202.11/src/base/bits.h b/mod/v8-14.6.202.11/src/base/bits.h
+index 179a10f..4791e96 100644
+--- a/orig/v8-14.6.202.11/src/base/bits.h
+++ b/mod/v8-14.6.202.11/src/base/bits.h
+@@ -270,11 +270,17 @@ inline constexpr uint32_t RoundDownToPowerOfTwo32(uint32_t value) {
+ }
+ 
+ // Precondition: 0 <= shift < 32
+#ifdef RotateRight32
+#undef RotateRight32
+#endif
+ inline constexpr uint32_t RotateRight32(uint32_t value, uint32_t shift) {
+   return (value >> shift) | (value << ((32 - shift) & 31));
+ }
+ 
+ // Precondition: 0 <= shift < 32
+#ifdef RotateLeft32
+#undef RotateLeft32
+#endif
+ inline constexpr uint32_t RotateLeft32(uint32_t value, uint32_t shift) {
+   return (value << shift) | (value >> ((32 - shift) & 31));
+ }
 diff --git a/orig/v8-14.6.202.11/src/base/debug/stack_trace_posix.cc b/mod/v8-14.6.202.11/src/base/debug/stack_trace_posix.cc
 index 6176ed4..a02043d 100644
 --- a/orig/v8-14.6.202.11/src/base/debug/stack_trace_posix.cc
@@ -23,36 +44,35 @@ index 6176ed4..a02043d 100644
 // Demangles C++ symbols in the given text. Example:
 //
 // "out/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
-
+diff --git a/orig/v8-14.6.202.11/src/base/export-template.h b/mod/v8-14.6.202.11/src/base/export-template.h
+index 861cfe4..1e73954 100644
+--- a/orig/v8-14.6.202.11/src/base/export-template.h
+++ b/mod/v8-14.6.202.11/src/base/export-template.h
+@@ -153,8 +153,10 @@
+ 
+ EXPORT_TEMPLATE_TEST(DEFAULT, );
+ EXPORT_TEMPLATE_TEST(DEFAULT, __attribute__((visibility("default"))));
+#if defined(_MSC_VER)
+ EXPORT_TEMPLATE_TEST(MSVC_HACK, __declspec(dllexport));
+ EXPORT_TEMPLATE_TEST(DEFAULT, __declspec(dllimport));
+#endif
+ 
+ #undef EXPORT_TEMPLATE_TEST
+ #undef EXPORT_TEMPLATE_TEST_DEFAULT_DEFAULT
 diff --git a/orig/v8-14.6.202.11/src/base/platform/platform-posix.cc b/mod/v8-14.6.202.11/src/base/platform/platform-posix.cc
-index 4c7d878..0e45eb3 100644
+index 420df0b..6f47969 100644
 --- a/orig/v8-14.6.202.11/src/base/platform/platform-posix.cc
 +++ b/mod/v8-14.6.202.11/src/base/platform/platform-posix.cc
-@@ -95,7 +95,7 @@
+@@ -95,7 +95,7 @@ extern int madvise(caddr_t, size_t, int);
 #endif
-
+ 
 #if defined(V8_LIBC_GLIBC)
 -extern "C" void* __libc_stack_end;
 +extern "C" void* __libc_stack_end V8_WEAK;
 #endif
-
+ 
 namespace v8 {
-@@ -1461,10 +1461,13 @@
-     // pthread_getattr_np can fail for the main thread.
-     // For the main thread we prefer using __libc_stack_end (if it exists) since
-     // it generally provides a tighter limit for CSS.
-    return __libc_stack_end;
-+    if (__libc_stack_end != nullptr) {
-+      return __libc_stack_end;
-+    }
- #else
-     return nullptr;
- #endif  // !defined(V8_LIBC_GLIBC)
-+    return nullptr;
-   }
-   void* base;
-   size_t size;
-@@ -1476,7 +1479,8 @@
+@@ -1476,7 +1476,8 @@ Stack::StackSlot Stack::ObtainCurrentThreadStackStart() {
   // __libc_stack_end is process global and thus is only valid for
   // the main thread. Check whether this is the main thread by checking
   // __libc_stack_end is within the thread's stack.
@@ -62,7 +82,213 @@ index 4c7d878..0e45eb3 100644
     DCHECK(MainThreadIsCurrentThread());
     return __libc_stack_end;
   }
-
+diff --git a/orig/v8-14.6.202.11/src/base/platform/platform-win32.cc b/mod/v8-14.6.202.11/src/base/platform/platform-win32.cc
+index f5d9ddc..542ea1a 100644
+--- a/orig/v8-14.6.202.11/src/base/platform/platform-win32.cc
+++ b/mod/v8-14.6.202.11/src/base/platform/platform-win32.cc
+@@ -69,9 +69,7 @@ static_assert(offsetof(V8_CRITICAL_SECTION, SpinCount) ==
+ // Extra functions for MinGW. Most of these are the _s functions which are in
+ // the Microsoft Visual Studio C++ CRT.
+ #ifdef __MINGW32__
+-
+-
+-#ifndef __MINGW64_VERSION_MAJOR
+#if !defined(__MINGW64_VERSION_MAJOR)
+ 
+ #define _TRUNCATE 0
+ #define STRUNCATE 80
+@@ -81,9 +79,6 @@ inline void MemoryFence() {
+   __asm__ __volatile__("xchgl %%eax,%0 ":"=r" (barrier));
+ }
+ 
+-#endif  // __MINGW64_VERSION_MAJOR
+-
+-
+ int localtime_s(tm* out_tm, const time_t* time) {
+   tm* posix_local_time_struct = localtime_r(time, out_tm);
+   if (posix_local_time_struct == nullptr) return 1;
+@@ -134,6 +129,8 @@ int strncpy_s(char* dest, size_t dest_size, const char* source, size_t count) {
+   return 0;
+ }
+ 
+#endif  // !defined(__MINGW64_VERSION_MAJOR)
+
+ #endif  // __MINGW32__
+ 
+ namespace v8 {
+@@ -743,8 +740,10 @@ void OS::StrNCpy(char* dest, int length, const char* src, size_t n) {
+ }
+ 
+ 
+#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
+ #undef _TRUNCATE
+ #undef STRUNCATE
+#endif
+ 
+ DEFINE_LAZY_LEAKY_OBJECT_GETTER(RandomNumberGenerator,
+                                 GetPlatformRandomNumberGenerator)
+@@ -1894,3 +1893,4 @@ Stack::StackSlot Stack::GetCurrentStackPosition() {
+ 
+ }  // namespace base
+ }  // namespace v8
+
+diff --git a/orig/v8-14.6.202.11/src/base/platform/time.cc b/mod/v8-14.6.202.11/src/base/platform/time.cc
+index 8390288..cba6cd5 100644
+--- a/orig/v8-14.6.202.11/src/base/platform/time.cc
+++ b/mod/v8-14.6.202.11/src/base/platform/time.cc
+@@ -782,12 +782,12 @@ bool ThreadTicks::IsSupported() {
+ #elif defined(__PASE__)
+   // Thread CPU time accounting is unavailable in PASE
+   return false;
+#elif defined(V8_OS_WIN)
+  return IsSupportedWin();
+ #elif (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+     defined(V8_OS_DARWIN) || defined(V8_OS_ANDROID) ||                    \
+     defined(V8_OS_SOLARIS) || defined(V8_OS_ZOS)
+   return true;
+-#elif defined(V8_OS_WIN)
+-  return IsSupportedWin();
+ #else
+   return false;
+ #endif
+@@ -804,13 +804,13 @@ ThreadTicks ThreadTicks::Now() {
+   return ThreadTicks(ComputeThreadTicks());
+ #elif V8_OS_FUCHSIA
+   return ThreadTicks(GetFuchsiaThreadTicks());
+#elif V8_OS_WIN
+  return ThreadTicks::GetForThread(::GetCurrentThread());
+ #elif (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+     defined(V8_OS_ANDROID) || defined(V8_OS_ZOS)
+   return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
+ #elif V8_OS_SOLARIS
+   return ThreadTicks(gethrvtime() / Time::kNanosecondsPerMicrosecond);
+-#elif V8_OS_WIN
+-  return ThreadTicks::GetForThread(::GetCurrentThread());
+ #else
+   UNREACHABLE();
+ #endif
+diff --git a/orig/v8-14.6.202.11/src/heap/base/asm/x64/push_registers_masm.asm b/mod/v8-14.6.202.11/src/heap/base/asm/x64/push_registers_masm.asm
+index d0d0563..72e230b 100644
+--- a/orig/v8-14.6.202.11/src/heap/base/asm/x64/push_registers_masm.asm
+++ b/mod/v8-14.6.202.11/src/heap/base/asm/x64/push_registers_masm.asm
+@@ -1,70 +1,30 @@
+-;; Copyright 2020 the V8 project authors. All rights reserved.
+-;; Use of this source code is governed by a BSD-style license that can be
+-;; found in the LICENSE file.
+-
+-;; MASM syntax
+-;; https://docs.microsoft.com/en-us/cpp/assembler/masm/microsoft-macro-assembler-reference?view=vs-2019
+-
+-public PushAllRegistersAndIterateStack
+-
+-.code
+-PushAllRegistersAndIterateStack proc frame
+-    ;; Push all callee-saved registers to get them on the stack for conservative
+-    ;; stack scanning.
+-    ;;
+-    ;; We maintain 16-byte alignment at calls. There is an 8-byte return address
+-    ;; on the stack and we push 232 bytes which maintains 16-byte stack
+-    ;; alignment at the call.
+-    ;; Source: https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention
+-    ;;
+-    ;; rbp is callee-saved. Maintain proper frame pointer for debugging.
+-    push rbp
+-    .pushreg rbp
+-    mov rbp, rsp
+-    .setframe rbp, 0
+-    push 0CDCDCDh  ;; Dummy for alignment.
+-    .allocstack 8
+-    push rsi
+-    .pushreg rsi
+-    push rdi
+-    .pushreg rdi
+-    push rbx
+-    .pushreg rbx
+-    push r12
+-    .pushreg r12
+-    push r13
+-    .pushreg r13
+-    push r14
+-    .pushreg r14
+-    push r15
+-    .pushreg r15
+-    sub rsp, 160
+-    .allocstack 160
+-    .endprolog
+-    ;; Use aligned instrs as we are certain that the stack is properly aligned.
+-    movdqa  xmmword ptr [rsp + 144], xmm6
+-    movdqa  xmmword ptr [rsp + 128], xmm7
+-    movdqa  xmmword ptr [rsp + 112], xmm8
+-    movdqa  xmmword ptr [rsp + 96], xmm9
+-    movdqa  xmmword ptr [rsp + 80], xmm10
+-    movdqa  xmmword ptr [rsp + 64], xmm11
+-    movdqa  xmmword ptr [rsp + 48], xmm12
+-    movdqa  xmmword ptr [rsp + 32], xmm13
+-    movdqa  xmmword ptr [rsp + 16], xmm14
+-    movdqa  xmmword ptr [rsp], xmm15
+-    ;; Pass 1st parameter (rcx) unchanged (Stack*).
+-    ;; Pass 2nd parameter (rdx) unchanged (StackVisitor*).
+-    ;; Save 3rd parameter (r8; IterateStackCallback)
+-    mov r9, r8
+-    ;; Pass 3rd parameter as rsp (stack pointer).
+-    mov r8, rsp
+-    ;; Call the callback.
+-    call r9
+-    ;; Pop the callee-saved registers.
+-    add rsp, 224
+-    ;; Restore rbp as it was used as frame pointer.
+-    pop rbp
+-    ret
+-    PushAllRegistersAndIterateStack endp
+-
+-end
+.text
+.globl PushAllRegistersAndIterateStack
+.seh_proc PushAllRegistersAndIterateStack
+PushAllRegistersAndIterateStack:
+  push %rbp
+  .seh_pushreg %rbp
+  mov %rsp, %rbp
+  .seh_setframe %rbp, 0
+  push $0xCDCDCD
+  .seh_stackalloc 8
+  push %rsi
+  .seh_pushreg %rsi
+  push %rdi
+  .seh_pushreg %rdi
+  push %rbx
+  .seh_pushreg %rbx
+  push %r12
+  .seh_pushreg %r12
+  push %r13
+  .seh_pushreg %r13
+  push %r14
+  .seh_pushreg %r14
+  push %r15
+  .seh_pushreg %r15
+  sub $160, %rsp
+  .seh_stackalloc 160
+  # Preserve Windows unwind metadata even though this is now GNU syntax.
+  # Without the .seh_* directives, SEH and stack walking can mis-handle
+  # unwinding across this callback frame.
+  .seh_endprologue
+  movdqa %xmm6, 144(%rsp)
+  movdqa %xmm7, 128(%rsp)
+  movdqa %xmm8, 112(%rsp)
+  movdqa %xmm9, 96(%rsp)
+  movdqa %xmm10, 80(%rsp)
+  movdqa %xmm11, 64(%rsp)
+  movdqa %xmm12, 48(%rsp)
+  movdqa %xmm13, 32(%rsp)
+  movdqa %xmm14, 16(%rsp)
+  movdqa %xmm15, 0(%rsp)
+  mov %r8, %r9
+  mov %rsp, %r8
+  call *%r9
+  add $224, %rsp
+  pop %rbp
+  ret
+.seh_endproc
 diff --git a/orig/v8-14.6.202.11/src/libplatform/default-thread-isolated-allocator.cc b/mod/v8-14.6.202.11/src/libplatform/default-thread-isolated-allocator.cc
 index bda0e43..b44f1d9 100644
 --- a/orig/v8-14.6.202.11/src/libplatform/default-thread-isolated-allocator.cc
@@ -76,3 +302,26 @@ index bda0e43..b44f1d9 100644
   // PKU was broken on Linux kernels before 5.13 (see
   // https://lore.kernel.org/all/20210623121456.399107624@linutronix.de/).
   // A fix is also included in the 5.4.182 and 5.10.103 versions ("x86/fpu:
+diff --git a/orig/v8-14.6.202.11/src/profiler/heap-snapshot-generator.cc b/mod/v8-14.6.202.11/src/profiler/heap-snapshot-generator.cc
+index 27e748f..cbf886c 100644
+--- a/orig/v8-14.6.202.11/src/profiler/heap-snapshot-generator.cc
+++ b/mod/v8-14.6.202.11/src/profiler/heap-snapshot-generator.cc
+@@ -429,11 +429,11 @@ HeapSnapshot::HeapSnapshot(HeapProfiler* profiler,
+   static_assert(kSystemPointerSize != 4 || sizeof(HeapGraphEdge) == 12);
+   static_assert(kSystemPointerSize != 8 || sizeof(HeapGraphEdge) == 24);
+   static_assert(kSystemPointerSize != 4 || sizeof(HeapEntry) == 32);
+-#if V8_CC_MSVC
+#if V8_CC_MSVC || V8_OS_WIN
+   static_assert(kSystemPointerSize != 8 || sizeof(HeapEntry) == 48);
+ #else   // !V8_CC_MSVC
+   static_assert(kSystemPointerSize != 8 || sizeof(HeapEntry) == 40);
+-#endif  // !V8_CC_MSVC
+#endif  // !V8_CC_MSVC || V8_OS_WIN
+   memset(&gc_subroot_entries_, 0, sizeof(gc_subroot_entries_));
+ }
+ 
+@@ -3878,3 +3878,4 @@ void HeapSnapshotJSONSerializer::SerializeLocations() {
+ }
+ 
+ }  // namespace v8::internal
+
--- a/third_party/v8/BUILD.bazel
+++ b/third_party/v8/BUILD.bazel
@@ -64,12 +64,15 @@ alias(

 alias(
    name = "v8_146_4_0_aarch64_pc_windows_gnullvm",
-    actual = ":v8_146_4_0_aarch64_pc_windows_msvc",
+    # `rusty_v8` only ships prebuilt Windows archives for MSVC. Build the
+    # GNU-flavored archive in-tree so windows-gnullvm consumers can link
+    # against a matching ABI instead of trying to reuse the MSVC release.
+    actual = ":v8_146_4_0_aarch64_pc_windows_gnullvm_bazel",
 )

 alias(
    name = "v8_146_4_0_x86_64_pc_windows_gnullvm",
-    actual = ":v8_146_4_0_x86_64_pc_windows_msvc",
+    actual = ":v8_146_4_0_x86_64_pc_windows_gnullvm_bazel",
 )

 filegroup(
@@ -114,12 +117,16 @@ filegroup(

 alias(
    name = "src_binding_release_x86_64_pc_windows_gnullvm",
-    actual = ":src_binding_release_x86_64_pc_windows_msvc",
+    # `rusty_v8` does not publish a Windows GNU binding file. The generated
+    # binding only describes this V8 release's C++ API surface, so reuse the
+    # Linux release binding while the windows-gnullvm archive build is still
+    # experimental.
+    actual = ":src_binding_release_x86_64_unknown_linux_gnu",
 )

 alias(
    name = "src_binding_release_aarch64_pc_windows_gnullvm",
-    actual = ":src_binding_release_aarch64_pc_windows_msvc",
+    actual = ":src_binding_release_aarch64_unknown_linux_gnu",
 )

 alias(
@@ -167,6 +174,8 @@ genrule(
    name = "binding_cc",
    srcs = ["@v8_crate_146_4_0//:binding_cc"],
    outs = ["binding.cc"],
+    # Keep this as a literal shell snippet. The string-concatenated form looked
+    # cleaner in Starlark but produced a broken `sed` invocation in CI.
    cmd = """
      sed \
        -e '/#include "v8\\/src\\/flags\\/flags.h"/d' \
@@ -208,12 +217,24 @@ cc_static_library(
    features = V8_STATIC_LIBRARY_FEATURES,
 )

+cc_static_library(
+    name = "v8_146_4_0_aarch64_pc_windows_gnullvm_bazel",
+    deps = [":v8_146_4_0_binding"],
+    features = V8_STATIC_LIBRARY_FEATURES,
+)
+
 cc_static_library(
    name = "v8_146_4_0_x86_64_apple_darwin_bazel",
    deps = [":v8_146_4_0_binding"],
    features = V8_STATIC_LIBRARY_FEATURES,
 )

+cc_static_library(
+    name = "v8_146_4_0_x86_64_pc_windows_gnullvm_bazel",
+    deps = [":v8_146_4_0_binding"],
+    features = V8_STATIC_LIBRARY_FEATURES,
+)
+
 cc_static_library(
    name = "v8_146_4_0_x86_64_unknown_linux_gnu_bazel",
    deps = [":v8_146_4_0_binding"],
--- a/workspace_root_test_launcher.bat.tpl
+++ b/workspace_root_test_launcher.bat.tpl
@@ -41,11 +41,17 @@ if not defined manifest if exist "%~dpn0.runfiles_manifest" set "manifest=%~dpn0
 if not defined manifest if exist "%~f0.exe.runfiles_manifest" set "manifest=%~f0.exe.runfiles_manifest"

 if defined manifest if exist "%manifest%" (
-  for /f "usebackq tokens=1,* delims= " %%A in (`findstr /b /c:"%logical_path% " "%manifest%"`) do (
-    endlocal & set "%~1=%%B" & exit /b 0
-  )
-  for /f "usebackq tokens=1,* delims= " %%A in (`findstr /b /c:"%workspace_logical_path% " "%manifest%"`) do (
-    endlocal & set "%~1=%%B" & exit /b 0
+  rem Read the manifest directly instead of shelling out to findstr. In the
+  rem GitHub Windows runner, the nested `findstr` path produced
+  rem `FINDSTR: Cannot open D:MANIFEST`, which then broke runfile resolution for
+  rem Bazel tests even though the manifest file was present.
+  for /f "usebackq tokens=1,* delims= " %%A in ("%manifest%") do (
+    if "%%A"=="%logical_path%" (
+      endlocal & set "%~1=%%B" & exit /b 0
+    )
+    if "%%A"=="%workspace_logical_path%" (
+      endlocal & set "%~1=%%B" & exit /b 0
+    )
  )
 )
Author	SHA1	Message	Date
Michael Bolin	77137c412d	wip: experiment with windows bazel v8 build	2026-03-27 19:34:32 -07:00
Michael Bolin	ada573c8c1	ci: enable the Windows Bazel workflow path	2026-03-27 19:34:32 -07:00