Merge pull request #20574 from compnerd/lazy-metadata

IRGen: force lazy metadata initialization for PE/COFF

Author: compnerd

include/swift/AST/IRGenOptions.h

@@ -171,6 +171,10 @@ class IRGenOptions {
   /// Bypass resilience when accessing resilient frameworks.
   unsigned EnableResilienceBypass : 1;
 
+  /// Force lazy initialization of class metadata
+  /// Used on Windows to avoid cross-module references.
+  unsigned LazyInitializeClassMetadata : 1;
+
   /// The path to load legacy type layouts from.
   StringRef ReadTypeInfoPath;
 
@@ -221,10 +225,10 @@ class IRGenOptions {
         EmbedMode(IRGenEmbedMode::None), HasValueNamesSetting(false),
         ValueNames(false), EnableReflectionMetadata(true),
         EnableReflectionNames(true), EnableClassResilience(false),
-        EnableResilienceBypass(false), UseIncrementalLLVMCodeGen(true),
-        UseSwiftCall(false), GenerateProfile(false),
-        EnableDynamicReplacementChaining(false), CmdArgs(),
-        SanitizeCoverage(llvm::SanitizerCoverageOptions()),
+        EnableResilienceBypass(false), LazyInitializeClassMetadata(false),
+        UseIncrementalLLVMCodeGen(true), UseSwiftCall(false),
+        GenerateProfile(false), EnableDynamicReplacementChaining(false),
+        CmdArgs(), SanitizeCoverage(llvm::SanitizerCoverageOptions()),
         TypeInfoFilter(TypeInfoDumpFilter::All) {}
 
   // Get a hash of all options which influence the llvm compilation but are not

lib/Frontend/CompilerInvocation.cpp

@@ -1059,6 +1059,10 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     Opts.EnableResilienceBypass = true;
   }
 
+  // PE/COFF cannot deal with the cross-module reference to the metadata parent
+  // (e.g. NativeObject).  Force the lazy initialization of the VWT always.
+  Opts.LazyInitializeClassMetadata = Triple.isOSBinFormatCOFF();
+
   if (const Arg *A = Args.getLastArg(OPT_read_type_info_path_EQ)) {
     Opts.ReadTypeInfoPath = A->getValue();
   }

lib/IRGen/GenClass.cpp

@@ -276,7 +276,8 @@ namespace {
       return (ClassHasMissingMembers ||
               ClassHasResilientMembers ||
               ClassHasResilientAncestry ||
-              ClassHasGenericAncestry);
+              ClassHasGenericAncestry ||
+              IGM.getOptions().LazyInitializeClassMetadata);
     }
 
     bool doesMetadataRequireRelocation() const {

test/IRGen/dllimport.swift

@@ -40,7 +40,6 @@ public func g() {
 // CHECK-NO-OPT-DAG: declare dllimport void @swift_deallocObject(%swift.refcounted*, i32, i32)
 // CHECK-NO-OPT-DAG: declare dllimport void @swift_release(%swift.refcounted*)
 // CHECK-NO-OPT-DAG: declare dllimport %swift.refcounted* @swift_retain(%swift.refcounted* returned)
-// CHECK-NO-OPT-DAG: @"$s9dllexport1cCN" = external dllimport global %swift.type
 // CHECK-NO-OPT-DAG: @"$s9dllexport1pMp" = external dllimport global %swift.protocol
 // CHECK-NO-OPT-DAG: @"$sytN" = external dllimport global %swift.full_type
 // CHECK-NO-OPT-DAG: @"$sBoWV" = external dllimport global i8*
@@ -51,7 +50,6 @@ public func g() {
 
 // CHECK-OPT-DAG: declare dllimport %swift.refcounted* @swift_retain(%swift.refcounted* returned) local_unnamed_addr
 // CHECK-OPT-DAG: @"$sBoWV" = external dllimport global i8*
-// CHECK-OPT-DAG: @"$s9dllexport1cCN" = external dllimport global %swift.type
 // CHECK-OPT-DAG: @"__imp_$s9dllexport1pMp" = external externally_initialized constant %swift.protocol*
 // CHECK-OPT-DAG: declare dllimport swiftcc i8* @"$s9dllexport2ciAA1cCvau"()
 // CHECK-OPT-DAG: declare dllimport swiftcc %swift.metadata_response @"$s9dllexport1cCMa"(i32)