1 files changed, 48 insertions, 63 deletions

diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 83040b5..7580b469 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -500,7 +500,9 @@ void LinkerDriver::parseDirectives(InputFile *file) {
       file->symtab.parseAlternateName(arg->getValue());
       break;
     case OPT_arm64xsameaddress:
-      if (!file->symtab.isEC())
+      if (file->symtab.isEC())
+        parseSameAddress(arg->getValue());
+      else
         Warn(ctx) << arg->getSpelling()
                   << " is not allowed in non-ARM64EC files (" << toString(file)
                   << ")";
@@ -1318,13 +1320,9 @@ void LinkerDriver::convertResources() {
 }
 
 void LinkerDriver::maybeCreateECExportThunk(StringRef name, Symbol *&sym) {
-  Defined *def;
   if (!sym)
     return;
-  if (auto undef = dyn_cast<Undefined>(sym))
-    def = undef->getDefinedWeakAlias();
-  else
-    def = dyn_cast<Defined>(sym);
+  Defined *def = sym->getDefined();
   if (!def)
     return;
 
@@ -1356,11 +1354,7 @@ void LinkerDriver::createECExportThunks() {
     Symbol *sym = ctx.symtab.find(targetName);
     if (!sym)
       continue;
-    Defined *targetSym;
-    if (auto undef = dyn_cast<Undefined>(sym))
-      targetSym = undef->getDefinedWeakAlias();
-    else
-      targetSym = dyn_cast<Defined>(sym);
+    Defined *targetSym = sym->getDefined();
     if (!targetSym)
       continue;
 
@@ -2303,6 +2297,13 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
        args.filtered(OPT_dependentloadflag, OPT_dependentloadflag_opt))
     parseDependentLoadFlags(arg);
 
+  for (auto *arg : args.filtered(OPT_arm64xsameaddress)) {
+    if (ctx.hybridSymtab)
+      parseSameAddress(arg->getValue());
+    else
+      Warn(ctx) << arg->getSpelling() << " is allowed only on EC targets";
+  }
+
   if (tar) {
     llvm::TimeTraceScope timeScope("Reproducer: response file");
     tar->append(
@@ -2554,28 +2555,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
             e.symbolName = symtab.mangleMaybe(e.sym);
         }
 
-        // Add weak aliases. Weak aliases is a mechanism to give remaining
-        // undefined symbols final chance to be resolved successfully.
-        for (auto pair : symtab.alternateNames) {
-          StringRef from = pair.first;
-          StringRef to = pair.second;
-          Symbol *sym = symtab.find(from);
-          if (!sym)
-            continue;
-          if (auto *u = dyn_cast<Undefined>(sym)) {
-            if (u->weakAlias) {
-              // On ARM64EC, anti-dependency aliases are treated as undefined
-              // symbols unless a demangled symbol aliases a defined one, which
-              // is part of the implementation.
-              if (!symtab.isEC() || !u->isAntiDep)
-                continue;
-              if (!isa<Undefined>(u->weakAlias) &&
-                  !isArm64ECMangledFunctionName(u->getName()))
-                continue;
-            }
-            u->setWeakAlias(symtab.addUndefined(to));
-          }
-        }
+        symtab.resolveAlternateNames();
       });
 
       ctx.forEachActiveSymtab([&](SymbolTable &symtab) {
@@ -2697,12 +2677,46 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
     createECExportThunks();
 
   // Resolve remaining undefined symbols and warn about imported locals.
+  std::vector<Undefined *> aliases;
   ctx.forEachSymtab(
-      [&](SymbolTable &symtab) { symtab.resolveRemainingUndefines(); });
+      [&](SymbolTable &symtab) { symtab.resolveRemainingUndefines(aliases); });
 
   if (errorCount())
     return;
 
+  ctx.forEachActiveSymtab([](SymbolTable &symtab) {
+    symtab.initializeECThunks();
+    symtab.initializeLoadConfig();
+  });
+
+  // Identify unreferenced COMDAT sections.
+  if (config->doGC) {
+    if (config->mingw) {
+      // markLive doesn't traverse .eh_frame, but the personality function is
+      // only reached that way. The proper solution would be to parse and
+      // traverse the .eh_frame section, like the ELF linker does.
+      // For now, just manually try to retain the known possible personality
+      // functions. This doesn't bring in more object files, but only marks
+      // functions that already have been included to be retained.
+      ctx.forEachSymtab([&](SymbolTable &symtab) {
+        for (const char *n : {"__gxx_personality_v0", "__gcc_personality_v0",
+                              "rust_eh_personality"}) {
+          Defined *d = dyn_cast_or_null<Defined>(symtab.findUnderscore(n));
+          if (d && !d->isGCRoot) {
+            d->isGCRoot = true;
+            config->gcroot.push_back(d);
+          }
+        }
+      });
+    }
+
+    markLive(ctx);
+  }
+
+  ctx.symtab.initializeSameAddressThunks();
+  for (auto alias : aliases)
+    alias->resolveWeakAlias();
+
   if (config->mingw) {
     // Make sure the crtend.o object is the last object file. This object
     // file can contain terminating section chunks that need to be placed
@@ -2794,35 +2808,6 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   if (auto *arg = args.getLastArg(OPT_print_symbol_order))
     config->printSymbolOrder = arg->getValue();
 
-  if (ctx.symtab.isEC())
-    ctx.symtab.initializeECThunks();
-  ctx.forEachActiveSymtab(
-      [](SymbolTable &symtab) { symtab.initializeLoadConfig(); });
-
-  // Identify unreferenced COMDAT sections.
-  if (config->doGC) {
-    if (config->mingw) {
-      // markLive doesn't traverse .eh_frame, but the personality function is
-      // only reached that way. The proper solution would be to parse and
-      // traverse the .eh_frame section, like the ELF linker does.
-      // For now, just manually try to retain the known possible personality
-      // functions. This doesn't bring in more object files, but only marks
-      // functions that already have been included to be retained.
-      ctx.forEachSymtab([&](SymbolTable &symtab) {
-        for (const char *n : {"__gxx_personality_v0", "__gcc_personality_v0",
-                              "rust_eh_personality"}) {
-          Defined *d = dyn_cast_or_null<Defined>(symtab.findUnderscore(n));
-          if (d && !d->isGCRoot) {
-            d->isGCRoot = true;
-            config->gcroot.push_back(d);
-          }
-        }
-      });
-    }
-
-    markLive(ctx);
-  }
-
   // Needs to happen after the last call to addFile().
   convertResources();