Reland "[android] Re-adds ability to include both v8 snapshot types"

This is a reland of commit 87a4a1df82

The reland adds a dependency on v8_context_snapshot:buildflags in NaCL,
to fix lacros build issues.

Original change's description:
> [android] Re-adds ability to include both v8 snapshot types
>
> A reland of https://crrev.com/c/3209682, which allows selecting at
> runtime whether V8 uses the blink-generated context snapshot or not.
> This reland is both a rebase and an update, and as such has some
> mechanical differences with the original patch -- in particular, it
> switches to using BUILDFLAGS over `#if defined`.
>
> We're relanding this because we want to retry the experiment with
> various new differences (e.g. trying out enabling for just high-end
> Android, collecting metrics from partners rather than aggregated whole
> web performance, looking at metrics outside of CWV, experimenting with
> the impact on the trade-off space of alternative compression schemes
> for the snapshot).
>
> Original description:
>
> > And adds feature as to which one is used at runtime. Specific
> > parts:
> > . adds gn arg: include_both_v8_snapshots. At this time this is
> >   only supported on android. I will likely make it work on chromeos
> >   next.
> > . Adds feature kUseContextSnapshot. This feature is available if
> >   include_both_v8_snapshots is set.
> > . Adds switch kUseContextSnapshotSwitch. This is passed from browser
> >   to renderer if kUseContextSnapshot is enabled. A separate switch is
> >   used as at the time the v8 snapshot is loaded features have not been
> >   loaded.
> > And this updates a bunch of build targets accordingly.
>
> Bug: 40200623, 40539769
> Change-Id: I4e82581809321ec143b3c1484af4267279aa1e2f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5482109
> Reviewed-by: Richard (Torne) Coles <torne@chromium.org>
> Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1293558}

Bug: 40200623, 40539769
Cq-Include-Trybots: luci.chrome.try:linux-lacros-chrome
Change-Id: I5141e1a1ea488ffc3f539f941bf0c52297378e99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5491087
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Derek Schuff <dschuff@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1295360}

android_webview/lib/aw_main_delegate.cc

@@ -160,18 +160,26 @@ std::optional<int> AwMainDelegate::BasicStartupComplete() {
       cl->AppendSwitch(switches::kWebViewDrawFunctorUsesVulkan);
 
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
-#if BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
-    const gin::V8SnapshotFileType file_type =
-        gin::V8SnapshotFileType::kWithAdditionalContext;
-#else
-    const gin::V8SnapshotFileType file_type = gin::V8SnapshotFileType::kDefault;
-#endif
+#if !BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT) || BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
     base::android::RegisterApkAssetWithFileDescriptorStore(
         content::kV8Snapshot32DataDescriptor,
-        gin::V8Initializer::GetSnapshotFilePath(true, file_type));
+        gin::V8Initializer::GetSnapshotFilePath(
+            true, gin::V8SnapshotFileType::kDefault));
     base::android::RegisterApkAssetWithFileDescriptorStore(
         content::kV8Snapshot64DataDescriptor,
-        gin::V8Initializer::GetSnapshotFilePath(false, file_type));
+        gin::V8Initializer::GetSnapshotFilePath(
+            false, gin::V8SnapshotFileType::kDefault));
+#endif
+#if BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
+    base::android::RegisterApkAssetWithFileDescriptorStore(
+        content::kV8ContextSnapshot32DataDescriptor,
+        gin::V8Initializer::GetSnapshotFilePath(
+            true, gin::V8SnapshotFileType::kWithAdditionalContext));
+    base::android::RegisterApkAssetWithFileDescriptorStore(
+        content::kV8ContextSnapshot64DataDescriptor,
+        gin::V8Initializer::GetSnapshotFilePath(
+            false, gin::V8SnapshotFileType::kWithAdditionalContext));
+#endif
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
   }
 

chrome/BUILD.gn

@@ -969,7 +969,8 @@ if (is_win) {
       if (use_v8_context_snapshot) {
         sources += [ "$root_out_dir/$v8_context_snapshot_filename" ]
         public_deps += [ "//tools/v8_context_snapshot" ]
-      } else {
+      }
+      if (!use_v8_context_snapshot || include_both_v8_snapshots) {
         sources += [ "$root_out_dir/snapshot_blob.bin" ]
       }
     }

chrome/installer/mini_installer/BUILD.gn

@@ -232,7 +232,8 @@ action("mini_installer_archive") {
     if (use_v8_context_snapshot) {
       inputs += [ "$root_out_dir/$v8_context_snapshot_filename" ]
       deps += [ "//tools/v8_context_snapshot" ]
-    } else {
+    }
+    if (!use_v8_context_snapshot || include_both_v8_snapshots) {
       inputs += [ "$root_out_dir/snapshot_blob.bin" ]
       args += [ "--include_snapshotblob=1" ]
     }

components/nacl/common/BUILD.gn

@@ -56,7 +56,10 @@ if (enable_nacl) {
     ]
 
     # Deps required by the above headers.
-    deps = [ "//media:media_buildflags" ]
+    deps = [
+      "//media:media_buildflags",
+      "//tools/v8_context_snapshot:buildflags",
+    ]
   }
 
   static_library("common") {

content/DEPS

@@ -133,4 +133,8 @@ specific_include_rules = {
     "+content/shell/browser",
     "+content/shell/common",
   ],
+  "content_(features|switches).h": [
+    # content -> tools dependency is disallowed, except buildflags for switches.
+    "+tools/v8_context_snapshot/buildflags.h",
+  ],
 }

content/app/content_main_runner_impl.cc

@@ -224,15 +224,22 @@ namespace {
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA) && BUILDFLAG(IS_ANDROID)
 #if defined __LP64__
 #define kV8SnapshotDataDescriptor kV8Snapshot64DataDescriptor
+#define kV8ContextSnapshotDataDescriptor kV8ContextSnapshot64DataDescriptor
 #else
 #define kV8SnapshotDataDescriptor kV8Snapshot32DataDescriptor
+#define kV8ContextSnapshotDataDescriptor kV8ContextSnapshot32DataDescriptor
 #endif
 #endif
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
 
 gin::V8SnapshotFileType GetSnapshotType(const base::CommandLine& command_line) {
-#if BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+  if (command_line.HasSwitch(switches::kUseContextSnapshotSwitch)) {
+    return gin::V8SnapshotFileType::kWithAdditionalContext;
+  }
+  return gin::V8SnapshotFileType::kDefault;
+#elif BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
   return gin::V8SnapshotFileType::kWithAdditionalContext;
 #else
   return gin::V8SnapshotFileType::kDefault;
@@ -241,13 +248,13 @@ gin::V8SnapshotFileType GetSnapshotType(const base::CommandLine& command_line) {
 
 #if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_MAC)
 std::string GetSnapshotDataDescriptor(const base::CommandLine& command_line) {
-#if BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
-#if BUILDFLAG(IS_ANDROID)
-  // On android, the renderer loads the context snapshot directly.
-  return std::string();
-#else
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+  if (command_line.HasSwitch(switches::kUseContextSnapshotSwitch)) {
+    return kV8ContextSnapshotDataDescriptor;
+  }
+  return kV8SnapshotDataDescriptor;
+#elif BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
   return kV8ContextSnapshotDataDescriptor;
-#endif
 #else
   return kV8SnapshotDataDescriptor;
 #endif

content/browser/renderer_host/render_process_host_impl.cc

@@ -1736,7 +1736,7 @@ bool RenderProcessHostImpl::Init() {
 
     auto file_data = std::make_unique<ChildProcessLauncherFileData>();
 #if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_MAC)
-    file_data->files_to_preload = GetV8SnapshotFilesToPreload();
+    file_data->files_to_preload = GetV8SnapshotFilesToPreload(*cmd_line);
 #endif
 
     // Spawn the child process asynchronously to avoid blocking the UI thread.

content/browser/utility_process_host.cc

@@ -406,7 +406,7 @@ bool UtilityProcessHost::StartProcess() {
 #endif
 
 #if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_MAC)
-    file_data_->files_to_preload.merge(GetV8SnapshotFilesToPreload());
+    file_data_->files_to_preload.merge(GetV8SnapshotFilesToPreload(*cmd_line));
 #endif  // BUILDFLAG(IS_POSIX)
 
 #if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)

content/browser/v8_snapshot_files.cc

@@ -4,14 +4,18 @@
 
 #include "content/browser/v8_snapshot_files.h"
 
+#include "base/command_line.h"
+#include "base/feature_list.h"
 #include "build/build_config.h"
 #include "content/public/common/content_descriptor_keys.h"
+#include "content/public/common/content_features.h"
+#include "content/public/common/content_switches.h"
 #include "tools/v8_context_snapshot/buildflags.h"
 
 namespace content {
 
 std::map<std::string, absl::variant<base::FilePath, base::ScopedFD>>
-GetV8SnapshotFilesToPreload() {
+GetV8SnapshotFilesToPreload(base::CommandLine& process_command_line) {
   std::map<std::string, absl::variant<base::FilePath, base::ScopedFD>> files;
 #if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
 #if BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
@@ -22,13 +26,21 @@ GetV8SnapshotFilesToPreload() {
       base::FilePath(FILE_PATH_LITERAL("snapshot_blob.bin"));
 #endif
 #elif BUILDFLAG(IS_ANDROID)
-#if !BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
+#if !BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT) || BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+#if BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+  if (base::FeatureList::IsEnabled(features::kUseContextSnapshot)) {
+    process_command_line.AppendSwitch(switches::kUseContextSnapshotSwitch);
+    files[kV8ContextSnapshotDataDescriptor] = base::FilePath(
+        FILE_PATH_LITERAL(BUILDFLAG(V8_CONTEXT_SNAPSHOT_FILENAME)));
+  }
+#endif  // BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
   files[kV8Snapshot64DataDescriptor] =
       base::FilePath(FILE_PATH_LITERAL("assets/snapshot_blob_64.bin"));
   files[kV8Snapshot32DataDescriptor] =
       base::FilePath(FILE_PATH_LITERAL("assets/snapshot_blob_32.bin"));
 #elif BUILDFLAG(USE_V8_CONTEXT_SNAPSHOT)
-  // For USE_V8_CONTEXT_SNAPSHOT, the renderer reads the files directly.
+  files[kV8ContextSnapshotDataDescriptor] = base::FilePath(
+      FILE_PATH_LITERAL(BUILDFLAG(V8_CONTEXT_SNAPSHOT_FILENAME)));
 #endif
 #endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
   return files;

content/browser/v8_snapshot_files.h

@@ -12,6 +12,10 @@
 #include "base/files/scoped_file.h"
 #include "third_party/abseil-cpp/absl/types/variant.h"
 
+namespace base {
+class CommandLine;
+}
+
 namespace content {
 
 // Returns a mapping of V8 snapshot files to be preloaded for child processes
@@ -21,7 +25,7 @@ namespace content {
 // This mapping can be used in `content::ChildProcessLauncherFileData` when
 // constructing a ChildProcessLauncher.
 std::map<std::string, absl::variant<base::FilePath, base::ScopedFD>>
-GetV8SnapshotFilesToPreload();
+GetV8SnapshotFilesToPreload(base::CommandLine& process_command_line);
 
 }  // namespace content
 

content/public/common/BUILD.gn

@@ -89,6 +89,7 @@ source_set("static_switches") {
   deps = [
     "//build:chromeos_buildflags",
     "//media:media_buildflags",
+    "//tools/v8_context_snapshot:buildflags",
   ]
 }
 
@@ -107,6 +108,7 @@ source_set("switches") {
   deps = [
     "//build:chromeos_buildflags",
     "//media:media_buildflags",
+    "//tools/v8_context_snapshot:buildflags",
   ]
 
   configs += [ "//content:content_implementation" ]
@@ -255,6 +257,7 @@ source_set("common_sources") {
     "//services/service_manager/public/mojom",
     "//third_party/blink/public:blink_headers",
     "//third_party/blink/public/mojom:mojom_platform_headers",
+    "//tools/v8_context_snapshot:buildflags",
     "//ui/accessibility",
     "//ui/base/cursor/mojom:cursor_type",
     "//ui/gfx/geometry",

content/public/common/content_descriptor_keys.cc

@@ -14,6 +14,10 @@ const char kV8Snapshot64DataDescriptor[] = "v8_snapshot_64_data";
 
 const char kV8ContextSnapshotDataDescriptor[] = "v8_context_snapshot_data";
 
+const char kV8ContextSnapshot32DataDescriptor[] = "v8_context_snapshot_32_data";
+
+const char kV8ContextSnapshot64DataDescriptor[] = "v8_context_snapshot_64_data";
+
 const char kNetworkContextParentDirsDescriptor[] = "network_parent_dirs_pipe";
 
 }  // namespace content

content/public/common/content_descriptor_keys.h

@@ -14,6 +14,8 @@ extern const char kV8SnapshotDataDescriptor[];
 extern const char kV8Snapshot32DataDescriptor[];
 extern const char kV8Snapshot64DataDescriptor[];
 extern const char kV8ContextSnapshotDataDescriptor[];
+extern const char kV8ContextSnapshot32DataDescriptor[];
+extern const char kV8ContextSnapshot64DataDescriptor[];
 
 // A list of directories the network service needs (recursive) access to in
 // order to function.

content/public/common/content_features.cc

@@ -1028,6 +1028,13 @@ BASE_FEATURE(kUnrestrictedSharedArrayBuffer,
              "UnrestrictedSharedArrayBuffer",
              base::FEATURE_DISABLED_BY_DEFAULT);
 
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+// If enabled, blink's context snapshot is used rather than the v8 snapshot.
+BASE_FEATURE(kUseContextSnapshot,
+             "UseContextSnapshot",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+#endif
+
 // Allows user activation propagation to all frames having the same origin as
 // the activation notifier frame.  This is an intermediate measure before we
 // have an iframe attribute to declaratively allow user activation propagation

content/public/common/content_features.h

@@ -17,6 +17,7 @@
 #include "build/chromeos_buildflags.h"
 #include "content/common/content_export.h"
 #include "content/public/common/dips_utils.h"
+#include "tools/v8_context_snapshot/buildflags.h"
 
 namespace features {
 
@@ -216,6 +217,9 @@ CONTENT_EXPORT BASE_DECLARE_FEATURE(kTouchDragAndContextMenu);
 CONTENT_EXPORT extern const base::FeatureParam<int>
     kTouchDragMovementThresholdDip;
 #endif
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+CONTENT_EXPORT BASE_DECLARE_FEATURE(kUseContextSnapshot);
+#endif
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kUnrestrictedSharedArrayBuffer);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kUserActivationSameOriginVisibility);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kVerifyDidCommitParams);

content/public/common/content_switches.cc

@@ -812,6 +812,13 @@ const char kUseFakeUIForMediaStream[]     = "use-fake-ui-for-media-stream";
 // Texture target for CHROMIUM_image backed video frame textures.
 const char kVideoImageTextureTarget[] = "video-image-texture-target";
 
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+// Switch supplied to the renderer if the feature `kUseContextSnapshot` is
+// enabled. A switch is used as at the time the renderer needs this information
+// features have not yet been loaded.
+const char kUseContextSnapshotSwitch[] = "use-context-snapshot";
+#endif
+
 // Set when Chromium should use a mobile user agent.
 const char kUseMobileUserAgent[] = "use-mobile-user-agent";
 

content/public/common/content_switches.h

@@ -11,6 +11,7 @@
 #include "build/chromeos_buildflags.h"
 #include "content/common/content_export.h"
 #include "media/media_buildflags.h"
+#include "tools/v8_context_snapshot/buildflags.h"
 
 namespace switches {
 
@@ -216,6 +217,9 @@ CONTENT_EXPORT extern const char kUseFakeUIForDigitalIdentity[];
 CONTENT_EXPORT extern const char kUseFakeUIForFedCM[];
 CONTENT_EXPORT extern const char kUseFakeUIForMediaStream[];
 CONTENT_EXPORT extern const char kVideoImageTextureTarget[];
+#if BUILDFLAG(IS_ANDROID) && BUILDFLAG(INCLUDE_BOTH_V8_SNAPSHOTS)
+CONTENT_EXPORT extern const char kUseContextSnapshotSwitch[];
+#endif
 CONTENT_EXPORT extern const char kUseMobileUserAgent[];
 CONTENT_EXPORT extern const char kUseMockCertVerifierForTesting[];
 extern const char kUtilityCmdPrefix[];

content/shell/BUILD.gn

@@ -811,7 +811,8 @@ if (is_apple) {
       if (use_v8_context_snapshot) {
         sources += [ "$root_out_dir/$v8_context_snapshot_filename" ]
         public_deps += [ "//tools/v8_context_snapshot" ]
-      } else {
+      }
+      if (!use_v8_context_snapshot || include_both_v8_snapshots) {
         sources += [ "$root_out_dir/snapshot_blob.bin" ]
       }
     }

gin/BUILD.gn

@@ -135,10 +135,13 @@ if (is_android && enable_java_templates &&
   android_assets("v8_snapshot_assets") {
     if (v8_use_external_startup_data) {
       disable_compression = true
+      sources = []
+      deps = []
       if (use_v8_context_snapshot) {
-        deps = [ "//tools/v8_context_snapshot:v8_context_snapshot" ]
-        sources = [ "$root_build_dir/$v8_context_snapshot_filename" ]
-      } else {
+        deps += [ "//tools/v8_context_snapshot:v8_context_snapshot" ]
+        sources += [ "$root_build_dir/$v8_context_snapshot_filename" ]
+      }
+      if (!use_v8_context_snapshot || include_both_v8_snapshots) {
         if (current_cpu == "arm" || current_cpu == "x86") {
           _arch_suffix = "32"
         } else {
@@ -146,7 +149,7 @@ if (is_android && enable_java_templates &&
         }
         renaming_sources = [ "$root_build_dir/snapshot_blob.bin" ]
         renaming_destinations = [ "snapshot_blob_$_arch_suffix.bin" ]
-        deps = [ "//v8:run_mksnapshot_default" ]
+        deps += [ "//v8:run_mksnapshot_default" ]
       }
     }
   }
@@ -159,18 +162,21 @@ if (is_android && enable_java_templates &&
         assert(android_64bit_target_cpu,
                "32-bit targets shouldn't have secondary abi")
         disable_compression = true
+        sources = []
+        deps = []
         if (use_v8_context_snapshot) {
-          sources = [ "$root_out_dir/v8_context_snapshot_32.bin" ]
-          deps = [
+          sources += [ "$root_out_dir/v8_context_snapshot_32.bin" ]
+          deps += [
             "//tools/v8_context_snapshot($android_secondary_abi_toolchain)",
           ]
-        } else {
+        }
+        if (!use_v8_context_snapshot || include_both_v8_snapshots) {
           _secondary_abi_out_dir =
               get_label_info("//v8($android_secondary_abi_toolchain)",
                              "root_out_dir")
           renaming_sources = [ "$_secondary_abi_out_dir/snapshot_blob.bin" ]
           renaming_destinations = [ "snapshot_blob_32.bin" ]
-          deps = [
+          deps += [
             "//v8:run_mksnapshot_default($android_secondary_abi_toolchain)",
           ]
         }

headless/BUILD.gn

@@ -464,7 +464,8 @@ component("headless_non_renderer") {
     if (use_v8_context_snapshot) {
       data += [ "$root_out_dir/$v8_context_snapshot_filename" ]
       data_deps += [ "//tools/v8_context_snapshot" ]
-    } else {
+    }
+    if (!use_v8_context_snapshot || include_both_v8_snapshots) {
       data += [ "$root_out_dir/snapshot_blob.bin" ]
     }
   }

tools/v8_context_snapshot/BUILD.gn

@@ -31,6 +31,7 @@ buildflag_header("buildflags") {
   header = "buildflags.h"
   flags = [
     "USE_V8_CONTEXT_SNAPSHOT=$use_v8_context_snapshot",
+    "INCLUDE_BOTH_V8_SNAPSHOTS=$include_both_v8_snapshots",
     "V8_CONTEXT_SNAPSHOT_FILENAME=\"$v8_context_snapshot_filename\"",
   ]
 }

tools/v8_context_snapshot/v8_context_snapshot.gni

@@ -12,17 +12,24 @@ import("//build/config/chromeos/ui_mode.gni")
 import("//build/config/v8_target_cpu.gni")
 import("//v8/gni/v8.gni")
 
+declare_args() {
+  # If set, both snapshots are included. At this time, this only applicable to
+  # android. In other words, it will not work correctly on other platforms.
+  include_both_v8_snapshots = false
+}
+
 declare_args() {
   # TODO(crbug.com/40539769): Enable the feature on more environments.
   # Disable in mac and win cross builds since building Blink twice is slow.
   use_v8_context_snapshot =
-      !is_chromeos && !is_android && !is_castos && !is_fuchsia &&
-      # Android may build for both 64 bit and 32bit. When this happens, the
-      # v8_target_cpu will not equal the target_cpu (for example,
-      # v8_target_cpu == "arm" but target_os == "arm64").
-      (v8_target_cpu == target_cpu || target_os == "android") &&
-      !(host_toolchain == default_toolchain && is_msan) &&
-      !(is_win && host_os != "win") && !(is_mac && host_os != "mac")
+      include_both_v8_snapshots ||
+      (!is_chromeos && !is_android && !is_castos && !is_fuchsia &&
+       # Android may build for both 64 bit and 32bit. When this happens, the
+       # v8_target_cpu will not equal the target_cpu (for example,
+       # v8_target_cpu == "arm" but target_os == "arm64").
+       (v8_target_cpu == target_cpu || target_os == "android") &&
+       !(host_toolchain == default_toolchain && is_msan) &&
+       !(is_win && host_os != "win") && !(is_mac && host_os != "mac"))
 
   # We use a different filename for arm64 macOS builds so that the arm64 and
   # x64 snapshots can live side-by-side in a universal macOS app.