Revert "[LLD][COFF] Support CF guards on ARM64X (llvm#128440)"

This reverts commit 14bab65.
It causes lld-link to crash, posted repro at llvm#128440 (comment).

Author: ZequanWu

lld/COFF/Writer.cpp

@@ -1986,17 +1986,10 @@ static void maybeAddAddressTakenFunction(SymbolRVASet &addressTakenSyms,
     // Common is always data, so it is ignored.
     break;
   case Symbol::DefinedAbsoluteKind:
+  case Symbol::DefinedSyntheticKind:
     // Absolute is never code, synthetic generally isn't and usually isn't
     // determinable.
     break;
-  case Symbol::DefinedSyntheticKind:
-    // For EC export thunks, mark both the thunk itself and its target.
-    if (auto expChunk = dyn_cast_or_null<ECExportThunkChunk>(
-            cast<Defined>(s)->getChunk())) {
-      addSymbolToRVASet(addressTakenSyms, cast<Defined>(s));
-      addSymbolToRVASet(addressTakenSyms, expChunk->target);
-    }
-    break;
   case Symbol::LazyArchiveKind:
   case Symbol::LazyObjectKind:
   case Symbol::LazyDLLSymbolKind:
@@ -2061,11 +2054,9 @@ void Writer::createGuardCFTables() {
     // with /guard:cf.
     for (ObjFile *file : ctx.objFileInstances) {
       if (file->hasGuardCF()) {
-        ctx.forEachSymtab([&](SymbolTable &symtab) {
-          Symbol *flagSym = symtab.findUnderscore("__guard_flags");
-          cast<DefinedAbsolute>(flagSym)->setVA(
-              uint32_t(GuardFlags::CF_INSTRUMENTED));
-        });
+        Symbol *flagSym = ctx.symtab.findUnderscore("__guard_flags");
+        cast<DefinedAbsolute>(flagSym)->setVA(
+            uint32_t(GuardFlags::CF_INSTRUMENTED));
         break;
       }
     }
@@ -2147,10 +2138,8 @@ void Writer::createGuardCFTables() {
     guardFlags |= uint32_t(GuardFlags::CF_LONGJUMP_TABLE_PRESENT);
   if (config->guardCF & GuardCFLevel::EHCont)
     guardFlags |= uint32_t(GuardFlags::EH_CONTINUATION_TABLE_PRESENT);
-  ctx.forEachSymtab([guardFlags](SymbolTable &symtab) {
-    Symbol *flagSym = symtab.findUnderscore("__guard_flags");
-    cast<DefinedAbsolute>(flagSym)->setVA(guardFlags);
-  });
+  Symbol *flagSym = ctx.symtab.findUnderscore("__guard_flags");
+  cast<DefinedAbsolute>(flagSym)->setVA(guardFlags);
 }
 
 // Take a list of input sections containing symbol table indices and add those
@@ -2221,12 +2210,10 @@ void Writer::maybeAddRVATable(SymbolRVASet tableSymbols, StringRef tableSym,
     tableChunk = make<RVATableChunk>(std::move(tableSymbols));
   rdataSec->addChunk(tableChunk);
 
-  ctx.forEachSymtab([&](SymbolTable &symtab) {
-    Symbol *t = symtab.findUnderscore(tableSym);
-    Symbol *c = symtab.findUnderscore(countSym);
-    replaceSymbol<DefinedSynthetic>(t, t->getName(), tableChunk);
-    cast<DefinedAbsolute>(c)->setVA(tableChunk->getSize() / (hasFlag ? 5 : 4));
-  });
+  Symbol *t = ctx.symtab.findUnderscore(tableSym);
+  Symbol *c = ctx.symtab.findUnderscore(countSym);
+  replaceSymbol<DefinedSynthetic>(t, t->getName(), tableChunk);
+  cast<DefinedAbsolute>(c)->setVA(tableChunk->getSize() / (hasFlag ? 5 : 4));
 }
 
 // Create CHPE metadata chunks.