Bug 1807780 - Use -ivfsoverlay instead of liblowercase. r=firefox-build-system-reviewers,ahochheiden

Because this involves affecting the MSVC + Windows SDK packs, we need to do this for toolchain tasks as well as Firefox builds in a single pass. The MSVC + Windows SDK packs are altered to keep the original case instead of lowercasing everything (except .lib files), and contain an overlay file that we now automatically use from the WINSYSROOT. This requires adjusting some paths to match what the original case is, as well as removing everything related to the use of liblowercase, which conflicts with the use of the overlay file. People using liblowercase locally will still have a working setup as long as they don't set WINSYSROOT (it's new, so they won't have it), and don't have an overlay file in there (which they only would if they ran the new pack_vs.py). Differential Revision: https://phabricator.services.mozilla.com/D165596
2022-12-29 00:05:49 +00:00 · 2022-12-29 00:05:49 +00:00 · 007a7a25e5
--- a/build/midl.py
+++ b/build/midl.py
@ -2,6 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.

+import functools
 import os
 import shutil
 import subprocess
@ -25,11 +26,20 @@ def relativize(path, base=None):
    return os.path.relpath(path, base)


+@functools.lru_cache(maxsize=None)
+def files_in(path):
+    return {p.lower(): os.path.join(path, p) for p in os.listdir(path)}
+
+
 def search_path(paths, path):
    for p in paths:
        f = os.path.join(p, path)
        if os.path.isfile(f):
            return f
+        # try an case-insensitive match
+        maybe_match = files_in(p).get(path.lower())
+        if maybe_match:
+            return maybe_match
    raise RuntimeError(f"Cannot find {path}")


@ -90,8 +100,15 @@ def preprocess(base, input, flags):
        input = search_path(includes, input)
        # If there is a .acf file corresponding to the .idl we're processing,
        # we also want to preprocess that file because midl might look for it too.
-        if input.endswith(".idl") and os.path.exists(input[:-4] + ".acf"):
-            queue.append(input[:-4] + ".acf")
+        if input.lower().endswith(".idl"):
+            try:
+                acf = search_path(
+                    [os.path.dirname(input)], os.path.basename(input)[:-4] + ".acf"
+                )
+                if acf:
+                    queue.append(acf)
+            except RuntimeError:
+                pass
        command = preprocessor + [input]
        preprocessed = os.path.join(base, os.path.basename(input))
        subprocess.run(command, stdout=open(preprocessed, "wb"), check=True)
--- a/build/moz.configure/toolchain.configure
+++ b/build/moz.configure/toolchain.configure
@ -558,6 +558,11 @@ option(
 )


+@depends_if("WINSYSROOT", when=is_windows)
+def winsysroot(winsysroot):
+    return winsysroot[0]
+
+
 option(
    env="VC_PATH",
    nargs=1,
@ -571,7 +576,7 @@ option(
    vs_version,
    build_environment,
    "VC_PATH",
-    "WINSYSROOT",
+    winsysroot,
    when=is_windows,
 )
@imports("os")
@ -583,7 +588,7 @@ def vc_compiler_paths_for_version(host, vs_version, env, vc_path, winsysroot):
    if winsysroot:
        if vc_path:
            die("WINSYSROOT and VC_PATH cannot be set together.")
-        base_vc_path = os.path.join(winsysroot[0], "VC", "Tools", "MSVC")
+        base_vc_path = os.path.join(winsysroot, "VC", "Tools", "MSVC")
        versions = os.listdir(base_vc_path)
        vc_path = [os.path.join(base_vc_path, str(max(Version(v) for v in versions)))]
    if vc_path:
@ -606,8 +611,8 @@ def vc_compiler_paths_for_version(host, vs_version, env, vc_path, winsysroot):
        # Choose the newest version.
        path = all_versions[-1][1]
    host_dir = {
-        "x86_64": "HostX64",
-        "x86": "HostX86",
+        "x86_64": "Hostx64",
+        "x86": "Hostx86",
    }.get(host.cpu)
    if host_dir:
        path = os.path.join(path, "bin", host_dir)
@ -1180,6 +1185,7 @@ def compiler(
        sysroot,
        macos_target,
        multiarch_dir,
+        winsysroot,
    )
    @checking("whether %s can be used" % what, lambda x: bool(x))
    @imports(_from="mozbuild.shellutil", _import="quote")
@ -1192,6 +1198,7 @@ def compiler(
        sysroot,
        macos_target,
        multiarch_dir,
+        winsysroot,
    ):
        wrapper = list(compiler_wrapper or ())
        flags = []
@ -1308,6 +1315,23 @@ def compiler(
                    "Only clang-cl 8.0 or newer is supported (found version %s)"
                    % info.version
                )
+            if winsysroot:
+                overlay = os.path.join(winsysroot, "overlay.yaml")
+                if os.path.exists(overlay):
+                    overlay_flags = ["-Xclang", "-ivfsoverlay", "-Xclang", overlay]
+                    if info.version >= "16.0" or (
+                        # clang-cl 15 normally doesn't support the root-relative
+                        # overlay we use, but the bootstrapped clang-cl 15 is patched
+                        # to support it, so check we're using a patched version.
+                        info.version >= "15.0"
+                        and try_preprocess(
+                            wrapper + [compiler] + flags + overlay_flags,
+                            language,
+                            "",
+                            onerror=lambda: False,
+                        )
+                    ):
+                        flags.extend(overlay_flags)

        # If you want to bump the version check here ensure the version
        # is known for Xcode in get_compiler_info.
--- a/build/moz.configure/windows.configure
+++ b/build/moz.configure/windows.configure
@ -65,8 +65,8 @@ def get_sdk_dirs(sdk, subdir):
    def categorize(dirs):
        return {os.path.basename(d): d for d in dirs}

-    include_dirs = categorize(get_dirs_containing(sdk, "include", subdir))
-    lib_dirs = categorize(get_dirs_containing(sdk, "lib", subdir))
+    include_dirs = categorize(get_dirs_containing(sdk, "Include", subdir))
+    lib_dirs = categorize(get_dirs_containing(sdk, "Lib", subdir))

    valid_versions = sorted(set(include_dirs) & set(lib_dirs), reverse=True)
    return [
--- a/build/vs/pack_vs.py
+++ b/build/vs/pack_vs.py
@ -40,28 +40,64 @@ if __name__ == "__main__":
        unpacked = tmpdir / "unpack"
        extractPackages(selected, dl_cache, unpacked)
        stem = Path(Path(args.output.stem).stem)
+        vfs = {}
        # Create an archive containing all the paths in lowercase form for
        # cross-compiles.
-        with open(args.output, "wb") as f:
-            with ZstdCompressor().stream_writer(f) as z:
-                with tarfile.open(mode="w|", fileobj=z) as tar:
-                    for subpath, dest in (
-                        ("VC", "vc"),
-                        ("Program Files/Windows Kits/10", "windows kits/10"),
-                        ("DIA SDK", "dia sdk"),
-                    ):
-                        subpath = unpacked / subpath
-                        dest = Path(dest)
-                        for root, dirs, files in os.walk(subpath):
-                            relpath = Path(root).relative_to(subpath)
-                            for f in files:
-                                path = Path(root) / f
-                                info = tar.gettarinfo(path)
-                                with open(path, "rb") as fh:
-                                    info.name = str(stem / dest / relpath / f).lower()
-                                    # Set executable flag on .exe files, the Firefox build
-                                    # system wants it.
-                                    if info.name.endswith(".exe"):
-                                        info.mode |= (info.mode & 0o444) >> 2
-                                    print("Adding", info.name)
-                                    tar.addfile(info, fh)
+        with ZstdCompressor().stream_writer(open(args.output, "wb")) as z, tarfile.open(
+            mode="w|", fileobj=z
+        ) as tar:
+            for subpath in ("VC", "Program Files/Windows Kits/10", "DIA SDK"):
+                dest = subpath
+                if dest.startswith("Program Files/"):
+                    dest = dest[len("Program Files/") :]
+                subpath = unpacked / subpath
+                dest = Path(dest)
+                for root, dirs, files in os.walk(subpath):
+                    relpath = Path(root).relative_to(subpath)
+                    for f in files:
+                        path = Path(root) / f
+                        info = tar.gettarinfo(path)
+                        with open(path, "rb") as fh:
+                            lower_f = f.lower()
+                            # Ideally, we'd use the overlay for .libs too but as of
+                            # writing it's still impractical to use, so lowercase
+                            # them for now, that'll be enough.
+                            if lower_f.endswith(".lib"):
+                                f = lower_f
+                            info.name = str(stem / dest / relpath / f)
+                            # Set executable flag on .exe files, the Firefox build
+                            # system wants it.
+                            if lower_f.endswith(".exe"):
+                                info.mode |= (info.mode & 0o444) >> 2
+                            print("Adding", info.name)
+                            tar.addfile(info, fh)
+                            if lower_f.endswith((".h", ".idl")):
+                                vfs.setdefault(str(dest / relpath), []).append(f)
+            # Create an overlay file for use with clang's -ivfsoverlay flag.
+            overlay = {
+                "version": 0,
+                "case-sensitive": False,
+                "root-relative": "overlay-dir",
+                "overlay-relative": True,
+                "roots": [
+                    {
+                        "name": p,
+                        "type": "directory",
+                        "contents": [
+                            {
+                                "name": f,
+                                "type": "file",
+                                "external-contents": f"{p}/{f}",
+                            }
+                            for f in files
+                        ],
+                    }
+                    for p, files in vfs.items()
+                ],
+            }
+            overlay_yaml = tmpdir / "overlay.yaml"
+            with overlay_yaml.open("w") as fh:
+                fh.write(yaml.dump(overlay))
+            info = tar.gettarinfo(overlay_yaml)
+            info.name = str(stem / "overlay.yaml")
+            tar.addfile(info, overlay_yaml.open("rb"))
--- a/build/win32/mozconfig.vs2017
+++ b/build/win32/mozconfig.vs2017
@ -3,8 +3,8 @@ if [ -z "${VSPATH}" ]; then
 fi

 if [ -d "${VSPATH}" ]; then
-    export WIN32_REDIST_DIR="${VSPATH}/vc/redist/msvc/14.16.27012/x86/microsoft.vc141.crt"
-    export WIN_UCRT_REDIST_DIR="${VSPATH}/windows kits/10/redist/ucrt/dlls/x86"
+    export WIN32_REDIST_DIR="${VSPATH}/VC/Redist/MSVC/14.16.27012/x86/Microsoft.VC141.CRT"
+    export WIN_UCRT_REDIST_DIR="${VSPATH}/Windows Kits/10/Redist/ucrt/DLLs/x86"
    export WINSYSROOT="${VSPATH}"
 fi

--- a/build/win64/mozconfig.vs2017
+++ b/build/win64/mozconfig.vs2017
@ -3,7 +3,7 @@ if [ -z "${VSPATH}" ]; then
 fi

 if [ -d "${VSPATH}" ]; then
-    export WIN32_REDIST_DIR=${VSPATH}/vc/redist/msvc/14.16.27012/x64/microsoft.vc141.crt
-    export WIN_UCRT_REDIST_DIR="${VSPATH}/windows kits/10/redist/ucrt/dlls/x64"
+    export WIN32_REDIST_DIR=${VSPATH}/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT
+    export WIN_UCRT_REDIST_DIR="${VSPATH}/Windows Kits/10/Redist/ucrt/DLLs/x64"
    export WINSYSROOT="${VSPATH}"
 fi
--- a/taskcluster/ci/build/windows.yml
+++ b/taskcluster/ci/build/windows.yml
@ -35,9 +35,6 @@ win32/debug:
        mozconfig-variant: debug
        extra-config:
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    use-sccache: true
    fetches:
        toolchain:
@ -50,7 +47,6 @@ win32/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -87,9 +83,6 @@ win32/opt:
        extra-config:
            stage_platform: win32
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['integration']
    use-sccache: true
    fetches:
@ -103,7 +96,6 @@ win32/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -140,9 +132,6 @@ win32-fuzzing/debug:
        extra-config:
            stage_platform: win32
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: debug-fuzzing
    run-on-projects: ['trunk']
    use-sccache: true
@ -157,7 +146,6 @@ win32-fuzzing/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -197,9 +185,6 @@ win64/debug:
        mozconfig-variant: debug
        extra-config:
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    use-sccache: true
    fetches:
        toolchain:
@ -212,7 +197,6 @@ win64/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -246,9 +230,6 @@ win64-hybrid/plain:
        mozconfig-variant: hybrid
        extra-config:
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    use-sccache: true
    run-on-projects: ['integration']
    fetches:
@ -262,7 +243,6 @@ win64-hybrid/plain:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -298,9 +278,6 @@ win64-fuzzing/debug:
            - builds/taskcluster_sub_win64/debug.py
        extra-config:
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: debug-fuzzing
    run-on-projects: ['trunk']
    use-sccache: true
@ -315,7 +292,6 @@ win64-fuzzing/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -397,13 +373,6 @@ win64/opt:
        extra-config:
            stage_platform: win64
            mozconfig_platform: win64
-            env:
-                # Setting LD_PRELOAD at the worker level would set it during
-                # fetch-content, which can fail randomly when a tar/unzip subprocess
-                # of fetch-content starts while the library is being extracted by
-                # another.
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['integration']
    use-sccache: true
    fetches:
@ -417,7 +386,6 @@ win64/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -514,9 +482,6 @@ win32-shippable/opt:
        extra-config:
            stage_platform: win32
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    fetches:
        toolchain:
            - linux64-clang
@ -527,7 +492,6 @@ win32-shippable/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -570,9 +534,6 @@ win64-shippable/opt:
        extra-config:
            stage_platform: win64
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    fetches:
        toolchain:
            - linux64-clang
@ -583,7 +544,6 @@ win64-shippable/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -615,9 +575,6 @@ win32-add-on-devel/opt:
        extra-config:
            stage_platform: win32-add-on-devel
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: add-on-devel
    run-on-projects: ['mozilla-beta', 'mozilla-release']
    use-sccache: true
@ -632,7 +589,6 @@ win32-add-on-devel/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -664,9 +620,6 @@ win64-add-on-devel/opt:
        extra-config:
            stage_platform: win64-on-devel
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: add-on-devel
    run-on-projects: ['mozilla-beta', 'mozilla-release']
    use-sccache: true
@ -681,7 +634,6 @@ win64-add-on-devel/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -714,9 +666,6 @@ win64-noopt/debug:
        mozconfig-variant: noopt-debug
        extra-config:
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['mozilla-central']
    use-sccache: true
    fetches:
@ -730,7 +679,6 @@ win64-noopt/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -763,9 +711,6 @@ win32-noopt/debug:
        mozconfig-variant: noopt-debug
        extra-config:
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['mozilla-central']
    use-sccache: true
    fetches:
@ -779,7 +724,6 @@ win32-noopt/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1087,9 +1031,6 @@ win64-asan/debug:
            - builds/taskcluster_sub_win64/asan_debug.py
        extra-config:
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: debug-asan
    use-sccache: true
    fetches:
@ -1103,7 +1044,6 @@ win64-asan/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1141,9 +1081,6 @@ win64-asan/opt:
        extra-config:
            stage_platform: win64-asan
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: nightly-asan
    use-sccache: true
    fetches:
@ -1157,7 +1094,6 @@ win64-asan/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1201,9 +1137,6 @@ win64-asan-reporter-shippable/opt:
        extra-config:
            stage_platform: win64-asan-reporter
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: nightly-asan-reporter
        mar-channel-id:
            firefox-mozilla-central-asan
@ -1220,7 +1153,6 @@ win64-asan-reporter-shippable/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1254,9 +1186,6 @@ win64-asan-fuzzing/opt:
        extra-config:
            stage_platform: win64-fuzzing-asan
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: nightly-fuzzing-asan
    use-sccache: true
    fetches:
@ -1270,7 +1199,6 @@ win64-asan-fuzzing/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1325,9 +1253,6 @@ win32-devedition/opt:
        extra-config:
            stage_platform: win32-devedition
            mozconfig_platform: win32
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: devedition
    run-on-projects: ['mozilla-beta']
    fetches:
@ -1340,7 +1265,6 @@ win32-devedition/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1382,9 +1306,6 @@ win64-devedition/opt:
        extra-config:
            stage_platform: win64-devedition
            mozconfig_platform: win64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: devedition
    run-on-projects: ['mozilla-beta']
    fetches:
@ -1397,7 +1318,6 @@ win64-devedition/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1433,9 +1353,6 @@ win64-aarch64/debug:
            - builds/taskcluster_sub_win64/debug.py
        extra-config:
            mozconfig_platform: win64-aarch64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: debug
    use-sccache: true
    fetches:
@ -1449,7 +1366,6 @@ win64-aarch64/debug:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1493,9 +1409,6 @@ win64-aarch64/opt:
        extra-config:
            stage_platform: win64-aarch64
            mozconfig_platform: win64-aarch64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['integration']
    use-sccache: true
    fetches:
@ -1509,7 +1422,6 @@ win64-aarch64/opt:
            - linux64-sccache
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1695,9 +1607,6 @@ win64-aarch64-shippable-no-eme/opt:
        extra-config:
            stage_platform: win64-aarch64
            mozconfig_platform: win64-aarch64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
    run-on-projects: ['all']
    fetches:
        toolchain:
@ -1709,7 +1618,6 @@ win64-aarch64-shippable-no-eme/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
@ -1853,9 +1761,6 @@ win64-aarch64-devedition-no-eme/opt:
        extra-config:
            stage_platform: win64-aarch64
            mozconfig_platform: win64-aarch64
-            env:
-                LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        mozconfig-variant: devedition
    run-on-projects: ['mozilla-beta']
    fetches:
@ -1868,7 +1773,6 @@ win64-aarch64-devedition-no-eme/opt:
            - linux64-cbindgen
            - linux64-dump_syms
            - linux64-wine
-            - linux64-liblowercase
            - linux64-winchecksec
            - nsis
            - sysroot-x86_64-linux-gnu
--- a/taskcluster/ci/instrumented-build/kind.yml
+++ b/taskcluster/ci/instrumented-build/kind.yml
@ -263,9 +263,6 @@ jobs:
            extra-config:
                stage_platform: win32
                mozconfig_platform: win32
-                env:
-                    LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                    LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        fetches:
            toolchain:
                - linux64-clang
@ -276,7 +273,6 @@ jobs:
                - linux64-cbindgen
                - linux64-dump_syms
                - linux64-wine
-                - linux64-liblowercase
                - linux64-winchecksec
                - nsis
                - sysroot-x86_64-linux-gnu
@ -303,9 +299,6 @@ jobs:
            extra-config:
                stage_platform: win64
                mozconfig_platform: win64
-                env:
-                    LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                    LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        fetches:
            toolchain:
                - linux64-clang
@ -316,7 +309,6 @@ jobs:
                - linux64-cbindgen
                - linux64-dump_syms
                - linux64-wine
-                - linux64-liblowercase
                - linux64-winchecksec
                - nsis
                - sysroot-x86_64-linux-gnu
--- a/taskcluster/ci/l10n/kind.yml
+++ b/taskcluster/ci/l10n/kind.yml
@ -49,7 +49,6 @@ job-template:
                    - linux64-hfsplus
                win.*:
                    - linux64-wine
-                    - linux64-liblowercase
                    - nsis
        fetch:
            by-build-platform:
--- a/taskcluster/ci/searchfox/kind.yml
+++ b/taskcluster/ci/searchfox/kind.yml
@ -123,9 +123,6 @@ jobs:
                - builds/taskcluster_sub_win64/searchfox_debug.py
            extra-config:
                mozconfig_platform: win64
-                env:
-                    LD_PRELOAD: "/builds/worker/fetches/liblowercase/liblowercase.so"
-                    LOWERCASE_DIRS: "/builds/worker/fetches/vs"
        use-sccache: true
        fetches:
            toolchain:
@ -138,7 +135,6 @@ jobs:
                - linux64-sccache
                - linux64-dump_syms
                - linux64-wine
-                - linux64-liblowercase
                - linux64-winchecksec
                - nsis
                - sysroot-x86_64-linux-gnu
--- a/taskcluster/ci/shippable-l10n/kind.yml
+++ b/taskcluster/ci/shippable-l10n/kind.yml
@ -56,7 +56,6 @@ job-template:
                    - linux64-hfsplus
                win.*:
                    - linux64-wine
-                    - linux64-liblowercase
                    - nsis
        fetch:
            by-build-platform:
--- a/taskcluster/ci/toolchain/cargo-vet.yml
+++ b/taskcluster/ci/toolchain/cargo-vet.yml
@ -61,5 +61,4 @@ win64-cargo-vet:
        toolchain:
            - linux64-clang-toolchain
            - linux64-rust-windows-toolchain
-            - linux64-liblowercase
            - win64-vs2017
--- a/taskcluster/ci/toolchain/cbindgen.yml
+++ b/taskcluster/ci/toolchain/cbindgen.yml
@ -64,5 +64,4 @@ win64-cbindgen:
        toolchain:
            - linux64-clang-toolchain
            - linux64-rust-windows-toolchain
-            - linux64-liblowercase
            - win64-vs2017
--- a/taskcluster/ci/toolchain/compiler-rt.yml
+++ b/taskcluster/ci/toolchain/compiler-rt.yml
@ -188,7 +188,6 @@ win32-compiler-rt-15:
            - clang-15
        toolchain:
            - linux64-clang-15-stage1
-            - linux64-liblowercase
            - win64-vs2019

 win64-compiler-rt-15:
@ -207,7 +206,6 @@ win64-compiler-rt-15:
            - clang-15
        toolchain:
            - linux64-clang-15-stage1
-            - linux64-liblowercase
            - win64-vs2019

 wasm32-wasi-compiler-rt-15:
@ -424,7 +422,6 @@ win32-compiler-rt-trunk:
            - clang-trunk
        toolchain:
            - linux64-clang-trunk-stage1
-            - linux64-liblowercase
            - win64-vs2019

 win64-compiler-rt-trunk:
@ -445,7 +442,6 @@ win64-compiler-rt-trunk:
            - clang-trunk
        toolchain:
            - linux64-clang-trunk-stage1
-            - linux64-liblowercase
            - win64-vs2019

 wasm32-wasi-compiler-rt-trunk:
--- a/taskcluster/ci/toolchain/dump-syms.yml
+++ b/taskcluster/ci/toolchain/dump-syms.yml
@ -62,5 +62,4 @@ win64-dump_syms:
        toolchain:
            - linux64-clang-toolchain
            - linux64-rust-windows-1.66
-            - linux64-liblowercase
            - win64-vs2017
--- a/taskcluster/ci/toolchain/fix-stacks.yml
+++ b/taskcluster/ci/toolchain/fix-stacks.yml
@ -60,7 +60,6 @@ win32-fix-stacks:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017

@ -72,6 +71,5 @@ win64-fix-stacks:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017
--- a/taskcluster/ci/toolchain/geckodriver.yml
+++ b/taskcluster/ci/toolchain/geckodriver.yml
@ -105,7 +105,6 @@ win32-geckodriver:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows
            - win64-vs2017

@ -121,7 +120,6 @@ win64-aarch64-geckodriver:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows
            - win64-vs2017

@ -137,6 +135,5 @@ win64-geckodriver:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows
            - win64-vs2017
--- a/taskcluster/ci/toolchain/grcov.yml
+++ b/taskcluster/ci/toolchain/grcov.yml
@ -46,6 +46,5 @@ win64-grcov:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017
--- a/taskcluster/ci/toolchain/llvm-symbolizer.yml
+++ b/taskcluster/ci/toolchain/llvm-symbolizer.yml
@ -118,7 +118,6 @@ win64-llvm-symbolizer-15:
            - clang-15
        toolchain:
            - linux64-clang-15-stage1
-            - linux64-liblowercase
            - win64-vs2019

 linux32-llvm-symbolizer-trunk:
@ -239,5 +238,4 @@ win64-llvm-symbolizer-trunk:
            - clang-trunk
        toolchain:
            - linux64-clang-trunk-stage1
-            - linux64-liblowercase
            - win64-vs2019
--- a/taskcluster/ci/toolchain/minidump-stackwalk.yml
+++ b/taskcluster/ci/toolchain/minidump-stackwalk.yml
@ -62,7 +62,6 @@ win32-minidump-stackwalk:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017

@ -74,7 +73,6 @@ win64-minidump-stackwalk:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017

--- a/taskcluster/ci/toolchain/misc.yml
+++ b/taskcluster/ci/toolchain/misc.yml
@ -279,7 +279,6 @@ win64-winchecksec:
            - winchecksec
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - win64-vs2017

 linux64-makecab:
@ -315,7 +314,6 @@ win64-mozmake:
            - gnumake
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - win64-vs2017

 nsis:
--- a/taskcluster/ci/toolchain/rust-size.yml
+++ b/taskcluster/ci/toolchain/rust-size.yml
@ -34,6 +34,5 @@ win64-rust-size:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017
--- a/taskcluster/ci/toolchain/sccache.yml
+++ b/taskcluster/ci/toolchain/sccache.yml
@ -85,6 +85,5 @@ win64-sccache:
    fetches:
        toolchain:
            - linux64-clang-toolchain
-            - linux64-liblowercase
            - linux64-rust-windows-toolchain
            - win64-vs2017
--- a/taskcluster/scripts/misc/build-geckodriver.sh
+++ b/taskcluster/scripts/misc/build-geckodriver.sh
@ -19,8 +19,8 @@ case "$TARGET" in
  . $GECKO_PATH/taskcluster/scripts/misc/vs-setup.sh
  # Bug 1584530: don't require the Microsoft MSVC runtime to be installed.
  export RUSTFLAGS="-Ctarget-feature=+crt-static -C linker=$MOZ_FETCHES_DIR/clang/bin/lld-link"
-  export LD_PRELOAD=$MOZ_FETCHES_DIR/liblowercase/liblowercase.so
-  export LOWERCASE_DIRS=$MOZ_FETCHES_DIR/vs
+  export TARGET_CFLAGS="-Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
+  export TARGET_CXXFLAGS="-Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
  ;;
 # OSX cross builds are a bit harder
 *-apple-darwin)
--- a/taskcluster/scripts/misc/build-llvm-common.sh
+++ b/taskcluster/scripts/misc/build-llvm-common.sh
@ -126,8 +126,6 @@ case "$target" in
  "
  ;;
 *-pc-windows-msvc)
-  export LD_PRELOAD="/builds/worker/fetches/liblowercase/liblowercase.so"
-  export LOWERCASE_DIRS="/builds/worker/fetches/vs"
  EXTRA_CMAKE_FLAGS="
    $EXTRA_CMAKE_FLAGS
    -DCMAKE_TOOLCHAIN_FILE=$MOZ_FETCHES_DIR/llvm-project/llvm/cmake/platforms/WinMsvc.cmake
--- a/taskcluster/scripts/misc/build-mozmake.sh
+++ b/taskcluster/scripts/misc/build-mozmake.sh
@ -50,14 +50,12 @@ EOF

 chmod +w src/config.h.W32
 sed "/#define BATCH_MODE_ONLY_SHELL/s/\/\*\(.*\)\*\//\1/" src/config.h.W32 > src/config.h
-export LD_PRELOAD=$MOZ_FETCHES_DIR/liblowercase/liblowercase.so
-export LOWERCASE_DIRS=$MOZ_FETCHES_DIR/vs
 make -f Basic.mk \
  MAKE_HOST=Windows32 \
  MKDIR.cmd='mkdir -p $1' \
  RM.cmd='rm -f $1' \
  CP.cmd='cp $1 $2' \
-  msvc_CC=$MOZ_FETCHES_DIR/clang/bin/clang-cl \
+  msvc_CC="$MOZ_FETCHES_DIR/clang/bin/clang-cl -Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml" \
  msvc_LD=$MOZ_FETCHES_DIR/clang/bin/lld-link

 mkdir mozmake
--- a/taskcluster/scripts/misc/build-rust-based-toolchain.sh
+++ b/taskcluster/scripts/misc/build-rust-based-toolchain.sh
@ -44,8 +44,8 @@ x86_64-unknown-linux-gnu)
    . $GECKO_PATH/taskcluster/scripts/misc/vs-setup.sh
    export CARGO_TARGET_I686_PC_WINDOWS_MSVC_LINKER=$MOZ_FETCHES_DIR/clang/bin/lld-link
    export CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_LINKER=$MOZ_FETCHES_DIR/clang/bin/lld-link
-    export LD_PRELOAD=$MOZ_FETCHES_DIR/liblowercase/liblowercase.so
-    export LOWERCASE_DIRS=$MOZ_FETCHES_DIR/vs
+    export TARGET_CFLAGS="-Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
+    export TARGET_CXXFLAGS="-Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
    ;;
 esac

--- a/taskcluster/scripts/misc/build-winchecksec.sh
+++ b/taskcluster/scripts/misc/build-winchecksec.sh
@ -12,9 +12,6 @@ x86_64-pc-windows-msvc)
    SUFFIX=.exe
    export PATH="$MOZ_FETCHES_DIR/clang/bin:$PATH"

-    export LD_PRELOAD=$MOZ_FETCHES_DIR/liblowercase/liblowercase.so
-    export LOWERCASE_DIRS=$MOZ_FETCHES_DIR/vs
-
    . $GECKO_PATH/taskcluster/scripts/misc/vs-setup.sh

    # Patch pe-parse because clang-cl doesn't support /analyze.
@ -34,8 +31,8 @@ EOF
      -DCMAKE_CXX_COMPILER=clang-cl
      -DCMAKE_C_COMPILER=clang-cl
      -DCMAKE_LINKER=lld-link
-      -DCMAKE_C_FLAGS=-fuse-ld=lld
-      -DCMAKE_CXX_FLAGS="-fuse-ld=lld -EHsc"
+      -DCMAKE_C_FLAGS="-fuse-ld=lld -Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
+      -DCMAKE_CXX_FLAGS="-fuse-ld=lld -EHsc -Xclang -ivfsoverlay -Xclang $MOZ_FETCHES_DIR/vs/overlay.yaml"
      -DCMAKE_RC_COMPILER=llvm-rc
      -DCMAKE_MT=llvm-mt
      -DCMAKE_SYSTEM_NAME=Windows
--- a/taskcluster/scripts/misc/vs-setup.sh
+++ b/taskcluster/scripts/misc/vs-setup.sh
@ -1,13 +1,13 @@
 VSDIR=vs
 VSPATH="${MOZ_FETCHES_DIR}/${VSDIR}"
 UNIX_VSPATH="$(cd ${MOZ_FETCHES_DIR} && pwd)/${VSDIR}"
-VCDIR=vc/tools/msvc/14.16.27023
+VCDIR=VC/Tools/MSVC/14.16.27023
 if [ ! -d "${VSPATH}/${VCDIR}" ]; then
-    VCDIR=vc/tools/msvc/14.29.30133
+    VCDIR=VC/Tools/MSVC/14.29.30133
 fi
-SDKDIR="windows kits/10"
+SDKDIR="Windows Kits/10"
 SDK_VERSION=10.0.17134.0
-if [ ! -d "${VSPATH}/${SDKDIR}/lib/${SDK_VERSION}" ]; then
+if [ ! -d "${VSPATH}/${SDKDIR}/Lib/${SDK_VERSION}" ]; then
    SDK_VERSION=10.0.19041.0
 fi

@ -23,6 +23,6 @@ i686-pc-windows-msvc)
    ;;
 esac

-export INCLUDE="${VSPATH}/${VCDIR}/include;${VSPATH}/${VCDIR}/atlmfc/include;${VSPATH}/${SDKDIR}/include/${SDK_VERSION}/ucrt;${VSPATH}/${SDKDIR}/include/${SDK_VERSION}/shared;${VSPATH}/${SDKDIR}/include/${SDK_VERSION}/um;${VSPATH}/${SDKDIR}/include/${SDK_VERSION}/winrt;${VSPATH}/dia sdk/include"
-export LIB="${VSPATH}/${VCDIR}/lib/${SDK_CPU};${VSPATH}/${VCDIR}/atlmfc/lib/${SDK_CPU};${VSPATH}/${SDKDIR}/lib/${SDK_VERSION}/um/${SDK_CPU};${VSPATH}/${SDKDIR}/lib/${SDK_VERSION}/ucrt/${SDK_CPU};${VSPATH}/dia sdk/lib/amd64"
+export INCLUDE="${VSPATH}/${VCDIR}/include;${VSPATH}/${VCDIR}/atlmfc/include;${VSPATH}/${SDKDIR}/Include/${SDK_VERSION}/ucrt;${VSPATH}/${SDKDIR}/Include/${SDK_VERSION}/shared;${VSPATH}/${SDKDIR}/Include/${SDK_VERSION}/um;${VSPATH}/${SDKDIR}/Include/${SDK_VERSION}/winrt;${VSPATH}/dia sdk/include"
+export LIB="${VSPATH}/${VCDIR}/lib/${SDK_CPU};${VSPATH}/${VCDIR}/atlmfc/lib/${SDK_CPU};${VSPATH}/${SDKDIR}/Lib/${SDK_VERSION}/um/${SDK_CPU};${VSPATH}/${SDKDIR}/Lib/${SDK_VERSION}/ucrt/${SDK_CPU};${VSPATH}/dia sdk/lib/amd64"
 export PATH="${UNIX_VSPATH}/${VCDIR}/bin/hostx64/${SDK_CPU}:${UNIX_VSPATH}/${VCDIR}/bin/hostx86/x86:${UNIX_VSPATH}/${SDKDIR}/bin/${SDK_VERSION}/${SDK_CPU}:${UNIX_VSPATH}/redist/${SDK_CPU}/microsoft.vc141.crt:${UNIX_VSPATH}/${SDKDIR}/redist/ucrt/dlls/${SDK_CPU}:${UNIX_VSPATH}/dia sdk/bin/amd64:$PATH"