Revert "[snapshot] Rename embedded*.S files to .asm"

This reverts commit 68a7736b.

Reason for revert: Broke Bazel and gcc builds
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20-%20bazel%20-%20builder/2237/overview
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20gcc%20-%20builder/2103/overview

Original change's description:
> [snapshot] Rename embedded*.S files to .asm
>
> We want to use llvm-ml to assemble files on Windows, but it only
> recognizes .asm files as input files. See
> https://chromium-review.googlesource.com/c/v8/v8/+/3668287.
>
> Change-Id: I34ff6d2693a34653c8e22a7c2d093853505cd455
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3672420
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80782}

Change-Id: I92f4435aca26da16555734b95b9aabe3271af15c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3673428
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Owners-Override: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80784}

BUILD.bazel

@@ -3240,11 +3240,11 @@ filegroup(
         "src/init/setup-isolate-deserialize.cc",
     ] + select({
         "@v8//bazel/config:v8_target_arm": [
-            "google3/snapshots/arm/noicu/embedded.asm",
+            "google3/snapshots/arm/noicu/embedded.S",
             "google3/snapshots/arm/noicu/snapshot.cc",
         ],
         "@v8//bazel/config:v8_target_ia32": [
-            "google3/snapshots/ia32/noicu/embedded.asm",
+            "google3/snapshots/ia32/noicu/embedded.S",
             "google3/snapshots/ia32/noicu/snapshot.cc",
         ],
         "//conditions:default": [":noicu/generated_snapshot_files"],
@@ -3257,11 +3257,11 @@ filegroup(
         "src/init/setup-isolate-deserialize.cc",
     ] + select({
         "@v8//bazel/config:v8_target_arm": [
-            "google3/snapshots/arm/icu/embedded.asm",
+            "google3/snapshots/arm/icu/embedded.S",
             "google3/snapshots/arm/icu/snapshot.cc",
         ],
         "@v8//bazel/config:v8_target_ia32": [
-            "google3/snapshots/ia32/icu/embedded.asm",
+            "google3/snapshots/ia32/icu/embedded.S",
             "google3/snapshots/ia32/icu/snapshot.cc",
         ],
         "//conditions:default": [":icu/generated_snapshot_files"],

BUILD.gn

@@ -1527,7 +1527,7 @@ config("v8_gcov_coverage_ldflags") {
 # Actions
 #
 
-# Only for Windows clang builds. Converts the embedded.asm file produced by
+# Only for Windows clang builds. Converts the embedded.S file produced by
 # mksnapshot into an embedded.cc file with corresponding inline assembly.
 template("asm_to_inline_asm") {
   name = target_name
@@ -1544,11 +1544,11 @@ template("asm_to_inline_asm") {
 
     script = "tools/snapshot/asm_to_inline_asm.py"
     deps = [ ":run_mksnapshot_" + name ]
-    sources = [ "$target_gen_dir/embedded${suffix}.asm" ]
+    sources = [ "$target_gen_dir/embedded${suffix}.S" ]
     outputs = [ "$target_gen_dir/embedded${suffix}.cc" ]
     args = invoker.args
     args += [
-      rebase_path("$target_gen_dir/embedded${suffix}.asm", root_build_dir),
+      rebase_path("$target_gen_dir/embedded${suffix}.S", root_build_dir),
       rebase_path("$target_gen_dir/embedded${suffix}.cc", root_build_dir),
     ]
   }
@@ -2086,7 +2086,7 @@ action("generate_bytecode_builtins_list") {
 # Template to generate different V8 snapshots based on different runtime flags.
 # Can be invoked with run_mksnapshot(<name>). The target will resolve to
 # run_mksnapshot_<name>. If <name> is "default", no file suffixes will be used.
-# Otherwise files are suffixed, e.g. embedded_<name>.asm and
+# Otherwise files are suffixed, e.g. embedded_<name>.S and
 # snapshot_blob_<name>.bin.
 #
 # The template exposes the variables:
@@ -2131,7 +2131,7 @@ template("run_mksnapshot") {
       "--target_arch=$current_cpu",
 
       "--embedded_src",
-      rebase_path("$target_gen_dir/embedded${suffix}.asm", root_build_dir),
+      rebase_path("$target_gen_dir/embedded${suffix}.S", root_build_dir),
     ]
 
     if (v8_enable_builtins_profiling) {
@@ -2157,7 +2157,7 @@ template("run_mksnapshot") {
 
     args += invoker.args
 
-    outputs += [ "$target_gen_dir/embedded${suffix}.asm" ]
+    outputs += [ "$target_gen_dir/embedded${suffix}.S" ]
     if (invoker.embedded_variant != "") {
       args += [
         "--embedded_variant",
@@ -2320,7 +2320,7 @@ v8_source_set("v8_snapshot") {
     deps += [ ":asm_to_inline_asm_default" ]
     sources += [ "$target_gen_dir/embedded.cc" ]
   } else {
-    sources += [ "$target_gen_dir/embedded.asm" ]
+    sources += [ "$target_gen_dir/embedded.S" ]
   }
 
   configs = [ ":internal_config" ]

bazel/defs.bzl

@@ -409,7 +409,7 @@ v8_target_cpu_transition = transition(
 def _mksnapshot(ctx):
     outs = [
         ctx.actions.declare_file(ctx.attr.prefix + "/snapshot.cc"),
-        ctx.actions.declare_file(ctx.attr.prefix + "/embedded.asm"),
+        ctx.actions.declare_file(ctx.attr.prefix + "/embedded.S"),
     ]
     ctx.actions.run(
         outputs = outs,

src/snapshot/embedded/embedded-file-writer.h

@@ -23,7 +23,7 @@
 
 namespace v8 {
 namespace internal {
-// Generates the embedded.asm file which is later compiled into the final v8
+// Generates the embedded.S file which is later compiled into the final v8
 // binary. Its contents are exported through two symbols:
 //
 // v8_<variant>_embedded_blob_ (intptr_t):

src/snapshot/embedded/platform-embedded-file-writer-base.h

@@ -45,7 +45,7 @@ enum class EmbeddedTargetArch {
 };
 
 // The platform-dependent logic for emitting assembly code for the generated
-// embedded.asm file.
+// embedded.S file.
 class PlatformEmbeddedFileWriterBase {
  public:
   virtual ~PlatformEmbeddedFileWriterBase() = default;

src/snapshot/embedded/platform-embedded-file-writer-win.cc

@@ -694,7 +694,7 @@ DataDirective PlatformEmbeddedFileWriterWin::ByteChunkDataDirective() const {
 #if defined(V8_COMPILER_IS_MSVC)
   // Windows MASM doesn't have an .octa directive, use QWORDs instead.
   // Note: MASM *really* does not like large data streams. It takes over 5
-  // minutes to assemble the ~350K lines of embedded.asm produced when using
+  // minutes to assemble the ~350K lines of embedded.S produced when using
   // BYTE directives in a debug build. QWORD produces roughly 120KLOC and
   // reduces assembly time to ~40 seconds. Still terrible, but much better
   // than before. See also: https://crbug.com/v8/8475.

tools/snapshot/asm_to_inline_asm.py

@@ -7,7 +7,7 @@
 '''
 Converts a given file in clang assembly syntax to a corresponding
 representation in inline assembly. Specifically, this is used to convert
-embedded.asm to embedded.cc for Windows clang builds.
+embedded.S to embedded.cc for Windows clang builds.
 '''
 
 import argparse