IRGen: reuse linker directives collected from tbd gen to emit these symbols to IR

Author: nkcsgexi

include/swift/Subsystems.h

@@ -25,6 +25,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Mutex.h"
 
 #include <memory>
@@ -276,7 +277,8 @@ namespace swift {
                       StringRef ModuleName, const PrimarySpecificPaths &PSPs,
                       llvm::LLVMContext &LLVMContext,
                       ArrayRef<std::string> parallelOutputFilenames,
-                      llvm::GlobalVariable **outModuleHash = nullptr);
+                      llvm::GlobalVariable **outModuleHash = nullptr,
+                      llvm::StringSet<> *LinkerDirectives = nullptr);
 
   /// Turn the given Swift module into either LLVM IR or native code
   /// and return the generated LLVM IR module.
@@ -286,7 +288,8 @@ namespace swift {
                       std::unique_ptr<SILModule> SILMod,
                       StringRef ModuleName, const PrimarySpecificPaths &PSPs,
                       llvm::LLVMContext &LLVMContext,
-                      llvm::GlobalVariable **outModuleHash = nullptr);
+                      llvm::GlobalVariable **outModuleHash = nullptr,
+                      llvm::StringSet<> *LinkerDirectives = nullptr);
 
   /// Given an already created LLVM module, construct a pass pipeline and run
   /// the Swift LLVM Pipeline upon it. This does not cause the module to be

include/swift/TBDGen/TBDGen.h

@@ -33,6 +33,9 @@ struct TBDGenOptions {
   /// Whether this compilation is producing a TBD for InstallAPI.
   bool IsInstallAPI;
 
+  /// Only collect linker directive symbols.
+  bool LinkerDirectivesOnly = false;
+
   /// The install_name to use in the TBD file.
   std::string InstallName;
 

lib/FrontendTool/FrontendTool.cpp

@@ -1347,18 +1347,20 @@ static void generateIR(IRGenOptions &IRGenOpts, std::unique_ptr<SILModule> SM,
                        StringRef OutputFilename, ModuleOrSourceFile MSF,
                        std::unique_ptr<llvm::Module> &IRModule,
                        llvm::GlobalVariable *&HashGlobal,
-                       ArrayRef<std::string> parallelOutputFilenames) {
+                       ArrayRef<std::string> parallelOutputFilenames,
+                       llvm::StringSet<> &LinkerDirectives) {
   // FIXME: We shouldn't need to use the global context here, but
   // something is persisting across calls to performIRGeneration.
   auto &LLVMContext = getGlobalLLVMContext();
   IRModule = MSF.is<SourceFile *>()
                  ? performIRGeneration(IRGenOpts, *MSF.get<SourceFile *>(),
                                        std::move(SM), OutputFilename, PSPs,
-                                       LLVMContext, &HashGlobal)
+                                       LLVMContext, &HashGlobal,
+                                       &LinkerDirectives)
                  : performIRGeneration(IRGenOpts, MSF.get<ModuleDecl *>(),
                                        std::move(SM), OutputFilename, PSPs,
                                        LLVMContext, parallelOutputFilenames,
-                                       &HashGlobal);
+                                       &HashGlobal, &LinkerDirectives);
 }
 
 static bool processCommandLineAndRunImmediately(CompilerInvocation &Invocation,
@@ -1457,6 +1459,17 @@ static bool generateCode(CompilerInvocation &Invocation,
                      EffectiveLanguageVersion, OutputFilename, Stats);
 }
 
+static void collectLinkerDirectives(CompilerInvocation &Invocation,
+                                    ModuleOrSourceFile MSF,
+                                    llvm::StringSet<> &Symbols) {
+  auto tbdOpts = Invocation.getTBDGenOptions();
+  tbdOpts.LinkerDirectivesOnly = true;
+  if (MSF.is<SourceFile*>())
+    enumeratePublicSymbols(MSF.get<SourceFile*>(), Symbols, tbdOpts);
+  else
+    enumeratePublicSymbols(MSF.get<ModuleDecl*>(), Symbols, tbdOpts);
+}
+
 static bool performCompileStepsPostSILGen(
     CompilerInstance &Instance, CompilerInvocation &Invocation,
     std::unique_ptr<SILModule> SM, bool astGuaranteedToCorrespondToSIL,
@@ -1585,14 +1598,16 @@ static bool performCompileStepsPostSILGen(
     return processCommandLineAndRunImmediately(
         Invocation, Instance, std::move(SM), MSF, observer, ReturnValue);
 
+  llvm::StringSet<> LinkerDirectives;
+  collectLinkerDirectives(Invocation, MSF, LinkerDirectives);
   StringRef OutputFilename = PSPs.OutputFilename;
   std::vector<std::string> ParallelOutputFilenames =
     Invocation.getFrontendOptions().InputsAndOutputs.copyOutputFilenames();
   std::unique_ptr<llvm::Module> IRModule;
   llvm::GlobalVariable *HashGlobal;
   generateIR(
       IRGenOpts, std::move(SM), PSPs, OutputFilename, MSF, IRModule, HashGlobal,
-      ParallelOutputFilenames);
+      ParallelOutputFilenames, LinkerDirectives);
 
   // Walk the AST for indexing after IR generation. Walking it before seems
   // to cause miscompilation issues.

lib/IRGen/GenDecl.cpp

@@ -998,7 +998,7 @@ static bool hasCodeCoverageInstrumentation(SILFunction &f, SILModule &m) {
   return f.getProfiler() && m.getOptions().EmitProfileCoverageMapping;
 }
 
-void IRGenerator::emitGlobalTopLevel() {
+void IRGenerator::emitGlobalTopLevel(llvm::StringSet<> *linkerDirectives) {
   // Generate order numbers for the functions in the SIL module that
   // correspond to definitions in the LLVM module.
   unsigned nextOrderNumber = 0;
@@ -1018,7 +1018,11 @@ void IRGenerator::emitGlobalTopLevel() {
     CurrentIGMPtr IGM = getGenModule(wt.getProtocol()->getDeclContext());
     ensureRelativeSymbolCollocation(wt);
   }
-
+  if (linkerDirectives) {
+    for (auto &entry: *linkerDirectives) {
+      createLinkerDirectiveVariable(*PrimaryIGM, entry.getKey());
+    }
+  }
   for (SILGlobalVariable &v : PrimaryIGM->getSILModule().getSILGlobals()) {
     Decl *decl = v.getDecl();
     CurrentIGMPtr IGM = getGenModule(decl ? decl->getDeclContext() : nullptr);

lib/IRGen/IRGen.cpp

@@ -858,7 +858,8 @@ performIRGeneration(IRGenOptions &Opts, ModuleDecl *M,
                     std::unique_ptr<SILModule> SILMod, StringRef ModuleName,
                     const PrimarySpecificPaths &PSPs,
                     llvm::LLVMContext &LLVMContext, SourceFile *SF = nullptr,
-                    llvm::GlobalVariable **outModuleHash = nullptr) {
+                    llvm::GlobalVariable **outModuleHash = nullptr,
+                    llvm::StringSet<> *linkerDirectives = nullptr) {
   auto &Ctx = M->getASTContext();
   assert(!Ctx.hadError());
 
@@ -879,8 +880,9 @@ performIRGeneration(IRGenOptions &Opts, ModuleDecl *M,
 
   {
     FrontendStatsTracer tracer(Ctx.Stats, "IRGen");
+
     // Emit the module contents.
-    irgen.emitGlobalTopLevel();
+    irgen.emitGlobalTopLevel(linkerDirectives);
 
     if (SF) {
       IGM.emitSourceFile(*SF);
@@ -1068,7 +1070,8 @@ struct LLVMCodeGenThreads {
 static void performParallelIRGeneration(
     IRGenOptions &Opts, swift::ModuleDecl *M, std::unique_ptr<SILModule> SILMod,
     StringRef ModuleName, int numThreads,
-    ArrayRef<std::string> outputFilenames) {
+    ArrayRef<std::string> outputFilenames,
+    llvm::StringSet<> *linkerDirectives) {
 
   IRGenerator irgen(Opts, *SILMod);
 
@@ -1134,7 +1137,7 @@ static void performParallelIRGeneration(
   }
 
   // Emit the module contents.
-  irgen.emitGlobalTopLevel();
+  irgen.emitGlobalTopLevel(linkerDirectives);
 
   for (auto *File : M->getFiles()) {
     if (auto *SF = dyn_cast<SourceFile>(File)) {
@@ -1262,29 +1265,33 @@ std::unique_ptr<llvm::Module> swift::performIRGeneration(
     StringRef ModuleName, const PrimarySpecificPaths &PSPs,
     llvm::LLVMContext &LLVMContext,
     ArrayRef<std::string> parallelOutputFilenames,
-    llvm::GlobalVariable **outModuleHash) {
+    llvm::GlobalVariable **outModuleHash,
+    llvm::StringSet<> *LinkerDirectives) {
   if (SILMod->getOptions().shouldPerformIRGenerationInParallel() &&
       !parallelOutputFilenames.empty()) {
     auto NumThreads = SILMod->getOptions().NumThreads;
     ::performParallelIRGeneration(Opts, M, std::move(SILMod), ModuleName,
-                                  NumThreads, parallelOutputFilenames);
+                                  NumThreads, parallelOutputFilenames,
+                                  LinkerDirectives);
     // TODO: Parallel LLVM compilation cannot be used if a (single) module is
     // needed as return value.
     return nullptr;
   }
   return ::performIRGeneration(Opts, M, std::move(SILMod), ModuleName, PSPs,
-                               LLVMContext, nullptr, outModuleHash);
+                               LLVMContext, nullptr, outModuleHash,
+                               LinkerDirectives);
 }
 
 std::unique_ptr<llvm::Module> swift::
 performIRGeneration(IRGenOptions &Opts, SourceFile &SF,
                     std::unique_ptr<SILModule> SILMod,
                     StringRef ModuleName, const PrimarySpecificPaths &PSPs,
                     llvm::LLVMContext &LLVMContext,
-                    llvm::GlobalVariable **outModuleHash) {
+                    llvm::GlobalVariable **outModuleHash,
+                    llvm::StringSet<> *LinkerDirectives) {
   return ::performIRGeneration(Opts, SF.getParentModule(), std::move(SILMod),
                                ModuleName, PSPs, LLVMContext, &SF,
-                               outModuleHash);
+                               outModuleHash, LinkerDirectives);
 }
 
 void

lib/IRGen/IRGenModule.h

@@ -331,7 +331,7 @@ class IRGenerator {
 
   /// Emit functions, variables and tables which are needed anyway, e.g. because
   /// they are externally visible.
-  void emitGlobalTopLevel();
+  void emitGlobalTopLevel(llvm::StringSet<> *LinkerDirectives);
 
   /// Emit references to each of the protocol descriptors defined in this
   /// IR module.

lib/TBDGen/TBDGen.cpp

@@ -57,7 +57,10 @@ static bool isGlobalOrStaticVar(VarDecl *VD) {
 }
 
 void TBDGenVisitor::addSymbolInternal(StringRef name,
-                                      llvm::MachO::SymbolKind kind) {
+                                      llvm::MachO::SymbolKind kind,
+                                      bool isLinkerDirective) {
+  if (!isLinkerDirective && Opts.LinkerDirectivesOnly)
+    return;
   Symbols.addSymbol(kind, name, Targets);
   if (StringSymbols && kind == SymbolKind::GlobalSymbol) {
     auto isNewValue = StringSymbols->insert(name).second;
@@ -102,7 +105,8 @@ void TBDGenVisitor::addLinkerDirectiveSymbols(StringRef name,
       llvm::SmallString<64> Buffer;
       llvm::raw_svector_ostream OS(Buffer);
       OS << "$ld$hide$os" << CurMaj << "." << CurMin << "$" << name;
-      addSymbolInternal(OS.str(), llvm::MachO::SymbolKind::GlobalSymbol);
+      addSymbolInternal(OS.str(), llvm::MachO::SymbolKind::GlobalSymbol,
+                        /*LinkerDirective*/true);
     }
   }
 }
@@ -686,6 +690,12 @@ static bool isApplicationExtensionSafe(const LangOptions &LangOpts) {
          llvm::sys::Process::GetEnv("LD_APPLICATION_EXTENSION_SAFE");
 }
 
+static bool hasLinkerDirective(Decl *D) {
+  if (D->getAttrs().hasAttribute<OriginallyDefinedInAttr>())
+    return true;
+  return false;
+}
+
 static void enumeratePublicSymbolsAndWrite(ModuleDecl *M, FileUnit *singleFile,
                                            StringSet *symbols,
                                            llvm::raw_ostream *os,
@@ -734,6 +744,8 @@ static void enumeratePublicSymbolsAndWrite(ModuleDecl *M, FileUnit *singleFile,
     visitor.addMainIfNecessary(file);
 
     for (auto d : decls) {
+      if (opts.LinkerDirectivesOnly && !hasLinkerDirective(d))
+        continue;
       visitor.TopLevelDecl = d;
       SWIFT_DEFER { visitor.TopLevelDecl = nullptr; };
       visitor.visit(d);

lib/TBDGen/TBDGenVisitor.h

@@ -57,7 +57,8 @@ class TBDGenVisitor : public ASTVisitor<TBDGenVisitor> {
   Decl* TopLevelDecl = nullptr;
 
 private:
-  void addSymbolInternal(StringRef name, llvm::MachO::SymbolKind kind);
+  void addSymbolInternal(StringRef name, llvm::MachO::SymbolKind kind,
+                         bool isLinkerDirective = false);
   void addLinkerDirectiveSymbols(StringRef name, llvm::MachO::SymbolKind kind);
   void addSymbol(StringRef name, llvm::MachO::SymbolKind kind =
                                      llvm::MachO::SymbolKind::GlobalSymbol);

test/attr/Inputs/SymbolMove/LowLevel.swift

@@ -1,52 +1,52 @@
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 public func printMessageMoved() {
   print("Hello from LowLevel")
 }
 
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 public struct Entity {
     public let value = "LowLevel"
     public init() {}
     public func location() -> String { return "Entity from " + value }
 }
 
 // =================== Move protocol =================================//
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 public protocol Box {
   associatedtype Item
   var ItemKind: String { get }
   func getItem() -> Item
   func shape() -> String
 }
 
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 extension Box {
   public func shape() -> String { return "round"}
 }
 
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 public struct Candy {
   public var kind = "candy"
   public init() {}
 }
 
 // =================== Move enum ============================ //
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 public enum LanguageKind: Int {
   case Cpp = 1
   case Swift = 2
   case ObjC = 3
 }
 
 // =================== Move class ============================ //
-@available(OSX 10.8, *)
-@_originallyDefinedIn(module: "HighLevel", OSX 10.10)
+@available(OSX 10.7, *)
+@_originallyDefinedIn(module: "HighLevel", OSX 10.9)
 open class Vehicle {
     public init() {}
     public var currentSpeed = 40.0