Merge pull request swiftlang#28691 from nkcsgexi/tbdgen-ld-hide

TBDGen/IRGen: generate $ld$hide$os symbols for decls marked with @_originallyDefinedIn

Author: nkcsgexi

include/swift/AST/Attr.h

@@ -1625,6 +1625,8 @@ class OriginallyDefinedInAttr: public DeclAttribute {
   /// Indicates when the symbol was moved here.
   const llvm::VersionTuple MovedVersion;
 
+  /// Returns true if this attribute is active given the current platform.
+  bool isActivePlatform(const ASTContext &ctx) const;
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DAK_OriginallyDefinedIn;
   }

include/swift/AST/DiagnosticsSema.def

@@ -1467,6 +1467,15 @@ NOTE(option_set_empty_set_init,none,
 ERROR(originally_defined_in_dupe_platform,none,
       "duplicate version number for platform %0", (StringRef))
 
+ERROR(originally_definedin_topleve_decl,none,
+      "@%0 is only applicable to top-level decl", (StringRef))
+
+ERROR(originally_definedin_need_available,none,
+      "need @available attribute for @%0", (StringRef))
+
+ERROR(originally_definedin_must_after_available_version,none,
+      "moved version from @%0 must after introduced OS version", (StringRef))
+
 // Alignment attribute
 ERROR(alignment_not_power_of_two,none,
       "alignment value must be a power of two", ())

include/swift/Basic/SupplementaryOutputPaths.h

@@ -149,6 +149,16 @@ struct SupplementaryOutputPaths {
   /// \sa swift::emitSwiftInterface
   std::string ModuleInterfaceOutputPath;
 
+  /// The path to a .c file where we should declare $ld$add symbols for those
+  /// symbols moved to the current module.
+  /// When symbols are moved to this module, this module declares them as HIDE
+  /// for the OS versions prior to when the move happened. On the other hand, the
+  /// original module should ADD them for these OS versions. An executable
+  /// can choose the right library to link against depending on the deployment target.
+  /// This is a walk-around that linker directives cannot specify other install
+  /// name per symbol, we should eventually remove this.
+  std::string LdAddCFilePath;
+
   SupplementaryOutputPaths() = default;
   SupplementaryOutputPaths(const SupplementaryOutputPaths &) = default;
 
@@ -158,7 +168,7 @@ struct SupplementaryOutputPaths {
            ReferenceDependenciesFilePath.empty() &&
            SerializedDiagnosticsPath.empty() && LoadedModuleTracePath.empty() &&
            TBDPath.empty() && ModuleInterfaceOutputPath.empty() &&
-           ModuleSourceInfoOutputPath.empty();
+           ModuleSourceInfoOutputPath.empty() && LdAddCFilePath.empty();
   }
 };
 } // namespace swift

include/swift/Frontend/Frontend.h

@@ -385,6 +385,8 @@ class CompilerInvocation {
   /// fail an assert if not in that mode.
   std::string getModuleInterfaceOutputPathForWholeModule() const;
 
+  std::string getLdAddCFileOutputPathForWholeModule() const;
+
   SerializationOptions
   computeSerializationOptions(const SupplementaryOutputPaths &outs,
                               bool moduleIsPublic);

include/swift/Option/FrontendOptions.td

@@ -644,4 +644,7 @@ def type_info_dump_filter_EQ : Joined<["-"], "type-info-dump-filter=">,
   Flags<[FrontendOption]>,
   HelpText<"One of 'all', 'resilient' or 'fragile'">;
 
+def emit_ldadd_cfile_path
+  : Separate<["-"], "emit-ldadd-cfile-path">, MetaVarName<"<path>">,
+    HelpText<"Generate .c file defining symbols to add back">;
 } // end let Flags = [FrontendOption, NoDriverOption, HelpHidden]

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>
@@ -277,7 +278,8 @@ 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.
@@ -287,7 +289,8 @@ 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/AST/Attr.cpp

@@ -1244,6 +1244,10 @@ bool AvailableAttr::isActivePlatform(const ASTContext &ctx) const {
   return isPlatformActive(Platform, ctx.LangOpts);
 }
 
+bool OriginallyDefinedInAttr::isActivePlatform(const ASTContext &ctx) const {
+  return isPlatformActive(Platform, ctx.LangOpts);
+}
+
 bool AvailableAttr::isLanguageVersionSpecific() const {
   if (PlatformAgnostic ==
       PlatformAgnosticAvailabilityKind::SwiftVersionSpecific)

lib/AST/Decl.cpp

@@ -577,8 +577,12 @@ Result->X = SM.getLocFromExternalSource(Locs->SourceFilePath, Locs->X.Line,   \
 }
 
 StringRef Decl::getAlternateModuleName() const {
-  if (auto *OD = Attrs.getAttribute(DeclAttrKind::DAK_OriginallyDefinedIn)) {
-    return static_cast<const OriginallyDefinedInAttr*>(OD)->OriginalModuleName;
+  for (auto *Att: Attrs) {
+    if (auto *OD = dyn_cast<OriginallyDefinedInAttr>(Att)) {
+      if (OD->isActivePlatform(getASTContext())) {
+        return OD->OriginalModuleName;
+      }
+    }
   }
   for (auto *DC = getDeclContext(); DC; DC = DC->getParent()) {
     if (auto decl = DC->getAsDecl()) {
@@ -3535,7 +3539,11 @@ bool NominalTypeDecl::isResilient(ModuleDecl *M,
   case ResilienceExpansion::Minimal:
     return isResilient();
   case ResilienceExpansion::Maximal:
-    return M != getModuleContext() && isResilient();
+    // We consider this decl belongs to the module either it's currently
+    // defined in this module or it's originally defined in this module, which
+    // is specified by @_originallyDefinedIn
+    return M != getModuleContext() &&
+      M->getName().str() != getAlternateModuleName() && isResilient();
   }
   llvm_unreachable("bad resilience expansion");
 }

lib/Frontend/ArgsToFrontendOutputsConverter.cpp

@@ -302,11 +302,12 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
       options::OPT_emit_module_interface_path);
   auto moduleSourceInfoOutput = getSupplementaryFilenamesFromArguments(
       options::OPT_emit_module_source_info_path);
-
+  auto ldAddCFileOutput  = getSupplementaryFilenamesFromArguments(
+      options::OPT_emit_ldadd_cfile_path);
   if (!objCHeaderOutput || !moduleOutput || !moduleDocOutput ||
       !dependenciesFile || !referenceDependenciesFile ||
       !serializedDiagnostics || !fixItsOutput || !loadedModuleTrace || !TBD ||
-      !moduleInterfaceOutput || !moduleSourceInfoOutput) {
+      !moduleInterfaceOutput || !moduleSourceInfoOutput || !ldAddCFileOutput) {
     return None;
   }
   std::vector<SupplementaryOutputPaths> result;
@@ -328,6 +329,7 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
     sop.TBDPath = (*TBD)[i];
     sop.ModuleInterfaceOutputPath = (*moduleInterfaceOutput)[i];
     sop.ModuleSourceInfoOutputPath = (*moduleSourceInfoOutput)[i];
+    sop.LdAddCFilePath = (*ldAddCFileOutput)[i];
     result.push_back(sop);
   }
   return result;
@@ -446,6 +448,7 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
   sop.TBDPath = tbdPath;
   sop.ModuleInterfaceOutputPath = ModuleInterfaceOutputPath;
   sop.ModuleSourceInfoOutputPath = moduleSourceInfoOutputPath;
+  sop.LdAddCFilePath = pathsFromArguments.LdAddCFilePath;
   return sop;
 }
 
@@ -546,7 +549,8 @@ SupplementaryOutputPathsComputer::readSupplementaryOutputFileMap() const {
         options::OPT_emit_loaded_module_trace_path,
         options::OPT_emit_module_interface_path,
         options::OPT_emit_module_source_info_path,
-        options::OPT_emit_tbd_path)) {
+        options::OPT_emit_tbd_path,
+        options::OPT_emit_ldadd_cfile_path)) {
     Diags.diagnose(SourceLoc(),
                    diag::error_cannot_have_supplementary_outputs,
                    A->getSpelling(), "-supplementary-output-file-map");