[Embedded] Remove -mergeable-symbols

This option is no longer necessary, because we emit weak definitions for any imported modules. Fixes rdar://158364032.
2025-12-14 20:36:38 +01:00 · 2025-09-08 17:40:56 -07:00
parent 74e85c8416
commit 66a730b638
12 changed files with 24 additions and 38 deletions
--- a/include/swift/AST/IRGenOptions.h
+++ b/include/swift/AST/IRGenOptions.h
@@ -498,8 +498,6 @@ public:
  /// Internalize symbols (static library) - do not export any public symbols.
  unsigned InternalizeSymbols : 1;

-  unsigned MergeableSymbols : 1;
-
  /// Emit a section with references to class_ro_t* in generic class patterns.
  unsigned EmitGenericRODatas : 1;

@@ -645,7 +643,7 @@ public:
        WitnessMethodElimination(false), ConditionalRuntimeRecords(false),
        AnnotateCondFailMessage(false),
        InternalizeAtLink(false), InternalizeSymbols(false),
-        MergeableSymbols(false), EmitGenericRODatas(true),
+        EmitGenericRODatas(true),
        NoPreallocatedInstantiationCaches(false),
        DisableReadonlyStaticObjects(false), CollocatedMetadataFunctions(false),
        ColocateTypeDescriptors(true), UseRelativeProtocolWitnessTables(false),
--- a/include/swift/IRGen/Linking.h
+++ b/include/swift/IRGen/Linking.h
@@ -57,15 +57,10 @@ public:
  /// be promoted to public external. Used by the LLDB expression evaluator.
  bool ForcePublicDecls;

-  /// When true, allows duplicate external and hidden declarations by marking
-  /// them as linkonce / weak.
-  bool MergeableSymbols;
-
  explicit UniversalLinkageInfo(IRGenModule &IGM);

  UniversalLinkageInfo(const llvm::Triple &triple, bool hasMultipleIGMs,
-                       bool forcePublicDecls, bool isStaticLibrary,
-                       bool mergeableSymbols);
+                       bool forcePublicDecls, bool isStaticLibrary);

  /// In case of multiple llvm modules (in multi-threaded compilation) all
  /// private decls must be visible from other files.
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -3766,10 +3766,6 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,

  Opts.InternalizeSymbols = FrontendOpts.Static;

-  if (Args.hasArg(OPT_mergeable_symbols)) {
-    Opts.MergeableSymbols = true;
-  }
-
  if (Args.hasArg(OPT_disable_preallocated_instantiation_caches)) {
    Opts.NoPreallocatedInstantiationCaches = true;
  }
@@ -3906,6 +3902,10 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,

  Opts.DebugCallsiteInfo |= Args.hasArg(OPT_debug_callsite_info);

+  if (Args.hasArg(OPT_mergeable_symbols))
+    Diags.diagnose(SourceLoc(), diag::warn_flag_deprecated,
+                   "-mergeable-symbols");
+
  return false;
 }

--- a/lib/IRGen/GenDecl.cpp
+++ b/lib/IRGen/GenDecl.cpp
@@ -2332,8 +2332,6 @@ getIRLinkage(StringRef name, const UniversalLinkageInfo &info,

    if (hasNonUniqueDefinition)
      linkage = llvm::GlobalValue::WeakODRLinkage;
-    else if (info.MergeableSymbols)
-      linkage = llvm::GlobalValue::WeakODRLinkage;

    return {linkage, PublicDefinitionVisibility,
            info.Internalize ? llvm::GlobalValue::DefaultStorageClass
@@ -2352,8 +2350,6 @@ getIRLinkage(StringRef name, const UniversalLinkageInfo &info,
  case SILLinkage::Hidden:
    if (hasNonUniqueDefinition)
      return RESULT(WeakODR, Hidden, Default);
-    if (info.MergeableSymbols)
-      return RESULT(WeakODR, Hidden, Default);

    return RESULT(External, Hidden, Default);

--- a/lib/IRGen/Linking.cpp
+++ b/lib/IRGen/Linking.cpp
@@ -82,19 +82,16 @@ bool swift::irgen::useDllStorage(const llvm::Triple &triple) {
 UniversalLinkageInfo::UniversalLinkageInfo(IRGenModule &IGM)
    : UniversalLinkageInfo(IGM.Triple, IGM.IRGen.hasMultipleIGMs(),
                           IGM.IRGen.Opts.ForcePublicLinkage,
-                           IGM.IRGen.Opts.InternalizeSymbols,
-                           IGM.IRGen.Opts.MergeableSymbols) {}
+                           IGM.IRGen.Opts.InternalizeSymbols) {}

 UniversalLinkageInfo::UniversalLinkageInfo(const llvm::Triple &triple,
                                           bool hasMultipleIGMs,
                                           bool forcePublicDecls,
-                                           bool isStaticLibrary,
-                                           bool mergeableSymbols)
+                                           bool isStaticLibrary)
    : IsELFObject(triple.isOSBinFormatELF()),
      IsMSVCEnvironment(triple.isWindowsMSVCEnvironment()),
      UseDLLStorage(useDllStorage(triple)), Internalize(isStaticLibrary),
-      HasMultipleIGMs(hasMultipleIGMs), ForcePublicDecls(forcePublicDecls),
-      MergeableSymbols(mergeableSymbols) {}
+      HasMultipleIGMs(hasMultipleIGMs), ForcePublicDecls(forcePublicDecls) {}

 LinkEntity LinkEntity::forSILGlobalVariable(SILGlobalVariable *G,
                                            IRGenModule &IGM) {
--- a/lib/IRGen/TBDGenVisitor.h
+++ b/lib/IRGen/TBDGenVisitor.h
@@ -124,7 +124,7 @@ public:
                APIRecorder &recorder)
      : DataLayoutDescription(dataLayoutString),
        UniversalLinkInfo(target, opts.HasMultipleIGMs, /*forcePublic*/ false,
-                          /*static=*/false, /*mergeableSymbols*/false),
+                          /*static=*/false),
        SwiftModule(swiftModule), Opts(opts), recorder(recorder),
        previousInstallNameMap(parsePreviousModuleInstallNameMap()) {}

--- a/test/embedded/linkage-custom-entry-point.swift
+++ b/test/embedded/linkage-custom-entry-point.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -mergeable-symbols    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
-// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s

 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded
--- a/test/embedded/linkage-mergeable-dead-strip.swift
+++ b/test/embedded/linkage-mergeable-dead-strip.swift
@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)

-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -mergeable-symbols -O %s -emit-ir | %FileCheck %s --check-prefix=CHECK-IR
-// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -mergeable-symbols -O %s -c -o %t/a.o
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -O %s -emit-ir | %FileCheck %s --check-prefix=CHECK-IR
+// RUN: %target-swift-frontend -enable-experimental-feature Embedded -enable-experimental-feature SymbolLinkageMarkers -module-name main -O %s -c -o %t/a.o
 // RUN: %target-clang %target-clang-resource-dir-opt %t/a.o -o %t/a.out -dead_strip
 // RUN: %llvm-nm --defined-only --format=just-symbols --demangle %t/a.out | sort | %FileCheck %s --check-prefix=CHECK-NM
 // RUN: %target-run %t/a.out | %FileCheck %s
@@ -16,8 +16,8 @@ public func a_this_is_unused() { }
@_used
 public func b_this_is_unused_but_explicitly_retained() { }

-// CHECK-IR: define weak_odr {{.*}}@"$e4main16a_this_is_unusedyyF"()
-// CHECK-IR: define weak_odr {{.*}}@"$e4main40b_this_is_unused_but_explicitly_retainedyyF"()
+// CHECK-IR: define {{.*}}@"$e4main16a_this_is_unusedyyF"()
+// CHECK-IR: define {{.*}}@"$e4main40b_this_is_unused_but_explicitly_retainedyyF"()

 // CHECK-NM-NOT: $e4main14this_is_unusedyyF
 // CHECK-NM: $e4main40b_this_is_unused_but_explicitly_retainedyyF
--- a/test/embedded/linkage-mergeable.swift
+++ b/test/embedded/linkage-mergeable.swift
@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s

-// RUN: %target-swift-frontend -mergeable-symbols -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
+// RUN: %target-swift-frontend -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
 // RUN: %target-clang %target-clang-resource-dir-opt %t/a.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s

--- a/test/embedded/linkage-mergeable2.swift
+++ b/test/embedded/linkage-mergeable2.swift
@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s

-// RUN: %target-swift-frontend -mergeable-symbols -O -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -O -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
+// RUN: %target-swift-frontend -O -c -emit-module -o %t/MyModule.o %t/MyModule.swift   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -O -c              -o %t/a.o        %t/Main.swift -I %t -enable-experimental-feature Embedded
 // RUN: %target-clang %target-clang-resource-dir-opt %t/a.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s

--- a/test/embedded/linkage-mergeable3.swift
+++ b/test/embedded/linkage-mergeable3.swift
@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/split_file.py -o %t %s

-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
-// RUN: %target-swift-frontend -mergeable-symbols -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -num-threads 2 -O -c -emit-module -o %t/MyModule.o             %t/MyModule.swift                   -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -num-threads 2 -O -c              -o %t/MainA.o -o %t/MainB.o  %t/MainA.swift %t/MainB.swift -I %t -enable-experimental-feature Embedded -parse-as-library
 // RUN: %target-clang %target-clang-resource-dir-opt %t/MainA.o %t/MainB.o %t/MyModule.o -o %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s

--- a/test/embedded/linkage-public-exports.swift
+++ b/test/embedded/linkage-public-exports.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend %s -mergeable-symbols    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
-// RUN: %target-swift-frontend %s -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s    -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend %s -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s

 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_Embedded