SIL: Remove -sil-link-all frontend flag

It was only used in a few tests. Those tests now use -emit-sil instead
of -emit-silgen, with some functions marked @_transparent and a few
CHECK: lines changed now that the mandatory optimizations get to run.

Author: slavapestov

include/swift/Option/FrontendOptions.td

@@ -393,9 +393,6 @@ def sil_unroll_threshold : Separate<["-"], "sil-unroll-threshold">,
 def sil_merge_partial_modules : Flag<["-"], "sil-merge-partial-modules">,
   HelpText<"Merge SIL from all partial swiftmodules into the final module">;
 
-def sil_link_all : Flag<["-"], "sil-link-all">,
-  HelpText<"Link all SIL functions">;
-
 def sil_verify_all : Flag<["-"], "sil-verify-all">,
   HelpText<"Verify SIL after each transform">;
 

include/swift/SIL/SILModule.h

@@ -504,12 +504,6 @@ class SILModule {
   /// i.e. it can be linked by linkFunction.
   bool hasFunction(StringRef Name);
 
-  /// Link in all Witness Tables in the module.
-  void linkAllWitnessTables();
-
-  /// Link in all VTables in the module.
-  void linkAllVTables();
-
   /// Link all definitions in all segments that are logically part of
   /// the same AST module.
   void linkAllFromCurrentModule();

include/swift/SILOptimizer/PassManager/Passes.h

@@ -55,12 +55,6 @@ namespace swift {
   /// \brief Remove dead functions from \p M.
   void performSILDeadFunctionElimination(SILModule *M);
 
-  /// \brief Link a SILFunction declaration to the actual definition in the
-  /// serialized modules.
-  ///
-  /// \param M the SILModule on which to operate
-  void performSILLinking(SILModule *M);
-
   /// \brief Convert SIL to a lowered form suitable for IRGen.
   void runSILLoweringPasses(SILModule &M);
 

lib/Frontend/CompilerInvocation.cpp

@@ -576,15 +576,8 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
     }
   }
 
-  if (const Arg *A = Args.getLastArg(OPT_disable_sil_linking,
-                                     OPT_sil_link_all)) {
-    if (A->getOption().matches(OPT_disable_sil_linking))
-      Opts.LinkMode = SILOptions::LinkNone;
-    else if (A->getOption().matches(OPT_sil_link_all))
-      Opts.LinkMode = SILOptions::LinkAll;
-    else
-      llvm_unreachable("Unknown SIL linking option!");
-  }
+  if (const Arg *A = Args.getLastArg(OPT_disable_sil_linking))
+    Opts.LinkMode = SILOptions::LinkNone;
 
   if (Args.hasArg(OPT_sil_merge_partial_modules))
     Opts.MergePartialModules = true;

lib/FrontendTool/FrontendTool.cpp

@@ -980,13 +980,6 @@ static bool performCompile(CompilerInstance &Instance,
   return false;
 }
 
-/// If we are asked to link all, link all.
-static void linkAllIfNeeded(const CompilerInvocation &Invocation,
-                            SILModule *SM) {
-  if (Invocation.getSILOptions().LinkMode == SILOptions::LinkAll)
-    performSILLinking(SM);
-}
-
 /// Perform "stable" optimizations that are invariant across compiler versions.
 static bool performMandatorySILPasses(CompilerInvocation &Invocation,
                                       SILModule *SM,
@@ -1008,8 +1001,6 @@ static bool performMandatorySILPasses(CompilerInvocation &Invocation,
       return true;
   }
 
-  linkAllIfNeeded(Invocation, SM);
-
   if (Invocation.getSILOptions().MergePartialModules)
     SM->linkAllFromCurrentModule();
   return false;
@@ -1211,12 +1202,10 @@ static bool performCompileStepsPostSILGen(
 
   // We've been told to emit SIL after SILGen, so write it now.
   if (Action == FrontendOptions::ActionType::EmitSILGen) {
-    linkAllIfNeeded(Invocation, SM.get());
     return writeSIL(*SM, PSPs, Instance, Invocation);
   }
 
   if (Action == FrontendOptions::ActionType::EmitSIBGen) {
-    linkAllIfNeeded(Invocation, SM.get());
     serializeSIB(SM.get(), PSPs, Instance.getASTContext(), MSF);
     return Context.hadError();
   }

lib/SIL/SILModule.cpp

@@ -561,14 +561,6 @@ void SILModule::linkAllFromCurrentModule() {
                                   /*PrimaryFile=*/nullptr);
 }
 
-void SILModule::linkAllWitnessTables() {
-  getSILLoader()->getAllWitnessTables();
-}
-
-void SILModule::linkAllVTables() {
-  getSILLoader()->getAllVTables();
-}
-
 void SILModule::invalidateSILLoaderCaches() {
   getSILLoader()->invalidateCaches();
 }

lib/SILOptimizer/UtilityPasses/Link.cpp

@@ -20,15 +20,6 @@ using namespace swift;
 //                          Top Level Driver
 //===----------------------------------------------------------------------===//
 
-void swift::performSILLinking(SILModule *M) {
-  for (auto &Fn : *M)
-    M->linkFunction(&Fn, SILModule::LinkingMode::LinkAll);
-
-  M->linkAllWitnessTables();
-  M->linkAllVTables();
-}
-
-
 namespace {
 
 /// Copies code from the standard library into the user program to enable

test/SIL/Serialization/generic_shared_function.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -o %t %S/Inputs/generic_shared_function_helper.sil -module-name SILSource
-// RUN: %target-swift-frontend -emit-module -o %t -I %t -primary-file %s -module-name main -sil-link-all
+// RUN: %target-swift-frontend -emit-module -o %t -I %t -primary-file %s -module-name main
 
 // Just don't crash when using -primary-file and re-serializing a
 // generic shared_external SIL function.