[arm64][msvc] Implement missing functions in mksnapshot

Because this code is compile-time gated, it's bit-rotted as new
functions have come along. This patch brings things back to
parity with x86/x64.

Bug: v8:10012
Change-Id: Iba4cd1155a1ae46742ecddbed96f36938a10db48
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2066973Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Richard Townsend <richard.townsend@arm.com>
Cr-Commit-Position: refs/heads/master@{#66419}

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

@@ -484,6 +484,39 @@ void PlatformEmbeddedFileWriterWin::SectionRoData() {
           ARM64_DATA_ALIGNMENT_POWER);
 }
 
+void PlatformEmbeddedFileWriterWin::StartPdataSection() {
+  fprintf(fp_, "  AREA |.pdata|, DATA, ALIGN=%d, READONLY\n",
+          ARM64_DATA_ALIGNMENT_POWER);
+}
+
+void PlatformEmbeddedFileWriterWin::EndPdataSection() {}
+
+void PlatformEmbeddedFileWriterWin::StartXdataSection() {
+  fprintf(fp_, "  AREA |.xdata|, DATA, ALIGN=%d, READONLY\n",
+          ARM64_DATA_ALIGNMENT_POWER);
+}
+
+void PlatformEmbeddedFileWriterWin::EndXdataSection() {}
+
+void PlatformEmbeddedFileWriterWin::DeclareRvaToSymbol(const char* name,
+                                                       uint64_t offset) {
+  if (offset > 0) {
+    fprintf(fp_, "  DCD  %s + %llu\n", name, offset);
+  } else {
+    fprintf(fp_, "  DCD  %s\n", name);
+  }
+  // The default relocation entry generated by MSVC armasm64.exe for DCD
+  // directive is IMAGE_REL_ARM64_ADDR64 which represents relocation for
+  // 64-bit pointer instead of 32-bit RVA. Append RELOC with
+  // IMAGE_REL_ARM64_ADDR32NB(2) to generate correct relocation entry for
+  // 32-bit RVA.
+  fprintf(fp_, "  RELOC 2\n");
+}
+
+void PlatformEmbeddedFileWriterWin::DeclareExternalFunction(const char* name) {
+  fprintf(fp_, "  EXTERN %s\n", name);
+}
+
 void PlatformEmbeddedFileWriterWin::DeclareUint32(const char* name,
                                                   uint32_t value) {
   DeclareSymbolGlobal(name);