Merge pull request swiftlang#32461 from hamishknight/its-all-linked

Author: hamishknight

include/swift/AST/SILOptions.h

@@ -40,11 +40,6 @@ class SILOptions {
   /// Controls the aggressiveness of the loop unroller.
   int UnrollThreshold = 250;
 
-  /// Controls whether to pull in SIL from partial modules during the
-  /// merge modules step. Could perhaps be merged with the link mode
-  /// above but the interactions between all the flags are tricky.
-  bool MergePartialModules = false;
-
   /// Remove all runtime assertions during optimizations.
   bool RemoveRuntimeAsserts = false;
 

include/swift/Option/FrontendOptions.td

@@ -554,8 +554,9 @@ def sil_unroll_threshold : Separate<["-"], "sil-unroll-threshold">,
   MetaVarName<"<250>">,
   HelpText<"Controls the aggressiveness of loop unrolling">;
 
+// FIXME: This option is now redundant and should eventually be removed.
 def sil_merge_partial_modules : Flag<["-"], "sil-merge-partial-modules">,
-  HelpText<"Merge SIL from all partial swiftmodules into the final module">;
+  Alias<merge_modules>;
 
 def sil_verify_all : Flag<["-"], "sil-verify-all">,
   HelpText<"Verify SIL after each transform">;

include/swift/SIL/SILModule.h

@@ -561,10 +561,6 @@ class SILModule {
   /// i.e. it can be linked by linkFunction.
   bool hasFunction(StringRef Name);
 
-  /// Link all definitions in all segments that are logically part of
-  /// the same AST module.
-  void linkAllFromCurrentModule();
-
   /// Look up the SILWitnessTable representing the lowering of a protocol
   /// conformance, and collect the substitutions to apply to the referenced
   /// witnesses, if any.

include/swift/Serialization/SerializedSILLoader.h

@@ -74,10 +74,6 @@ class SerializedSILLoader {
 
   bool invalidateFunction(SILFunction *F);
 
-  /// Deserialize all SILFunctions, VTables, and WitnessTables in all
-  /// SILModules.
-  void getAll();
-
   /// Deserialize all SILFunctions, VTables, and WitnessTables for
   /// a given Module.
   ///

lib/Frontend/CompilerInvocation.cpp

@@ -1049,9 +1049,6 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   if (FEOpts.RequestedAction == FrontendOptions::ActionType::EmitModuleOnly)
     Opts.StopOptimizationAfterSerialization = true;
 
-  if (Args.hasArg(OPT_sil_merge_partial_modules))
-    Opts.MergePartialModules = true;
-
   // Propagate the typechecker's understanding of
   // -experimental-skip-non-inlinable-function-bodies to SIL.
   Opts.SkipNonInlinableFunctionBodies = TCOpts.SkipNonInlinableFunctionBodies;

lib/Frontend/Frontend.cpp

@@ -982,22 +982,17 @@ void CompilerInstance::freeASTContext() {
 /// Perform "stable" optimizations that are invariant across compiler versions.
 static bool performMandatorySILPasses(CompilerInvocation &Invocation,
                                       SILModule *SM) {
+  // Don't run diagnostic passes at all when merging modules.
   if (Invocation.getFrontendOptions().RequestedAction ==
       FrontendOptions::ActionType::MergeModules) {
-    // Don't run diagnostic passes at all.
-  } else if (!Invocation.getDiagnosticOptions().SkipDiagnosticPasses) {
-    if (runSILDiagnosticPasses(*SM))
-      return true;
-  } else {
+    return false;
+  }
+  if (Invocation.getDiagnosticOptions().SkipDiagnosticPasses) {
     // Even if we are not supposed to run the diagnostic passes, we still need
     // to run the ownership evaluator.
-    if (runSILOwnershipEliminatorPass(*SM))
-      return true;
+    return runSILOwnershipEliminatorPass(*SM);
   }
-
-  if (Invocation.getSILOptions().MergePartialModules)
-    SM->linkAllFromCurrentModule();
-  return false;
+  return runSILDiagnosticPasses(*SM);
 }
 
 /// Perform SIL optimization passes if optimizations haven't been disabled.

lib/SIL/IR/SILModule.cpp

@@ -427,11 +427,6 @@ bool SILModule::hasFunction(StringRef Name) {
   return getSILLoader()->hasSILFunction(Name);
 }
 
-void SILModule::linkAllFromCurrentModule() {
-  getSILLoader()->getAllForModule(getSwiftModule()->getName(),
-                                  /*PrimaryFile=*/nullptr);
-}
-
 void SILModule::invalidateSILLoaderCaches() {
   getSILLoader()->invalidateCaches();
 }

lib/SIL/Verifier/SILVerifier.cpp

@@ -1751,8 +1751,9 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
               "[dynamically_replaceable] function");
 
     // In canonical SIL, direct reference to a shared_external declaration
-    // is an error; we should have deserialized a body. In raw SIL, we may
-    // not have deserialized the body yet.
+    // is an error; we should have deserialized a body. In raw SIL, including
+    // the merge-modules phase, we may not have deserialized the body yet as we
+    // may not have run the SILLinker pass.
     if (F.getModule().getStage() >= SILStage::Canonical) {
       if (RefF->isExternalDeclaration()) {
         require(SingleFunction ||
@@ -5560,20 +5561,13 @@ void SILModule::verify() const {
   // Uniquing set to catch symbol name collisions.
   llvm::DenseSet<StringRef> symbolNames;
 
-  // When merging partial modules, we only link functions from the current
-  // module, without enabling "LinkAll" mode or running the SILLinker pass;
-  // in this case, we need to relax some of the checks.
-  bool SingleFunction = false;
-  if (getOptions().MergePartialModules)
-    SingleFunction = true;
-
   // Check all functions.
   for (const SILFunction &f : *this) {
     if (!symbolNames.insert(f.getName()).second) {
       llvm::errs() << "Symbol redefined: " << f.getName() << "!\n";
       assert(false && "triggering standard assertion failure routine");
     }
-    f.verify(SingleFunction);
+    f.verify(/*singleFunction*/ false);
   }
 
   // Check all globals.

lib/SILGen/SILGen.cpp

@@ -1928,12 +1928,12 @@ ASTLoweringRequest::evaluate(Evaluator &evaluator,
   }
 
   // Also make sure to process any intermediate files that may contain SIL.
-  bool hasSIB = llvm::any_of(desc.getFiles(), [](const FileUnit *File) -> bool {
-    auto *SASTF = dyn_cast<SerializedASTFile>(File);
-    return SASTF && SASTF->isSIB();
-  });
-  if (hasSIB) {
-    auto primary = desc.context.dyn_cast<FileUnit *>();
+  bool shouldDeserialize =
+      llvm::any_of(desc.getFiles(), [](const FileUnit *File) -> bool {
+        return isa<SerializedASTFile>(File);
+      });
+  if (shouldDeserialize) {
+    auto *primary = desc.context.dyn_cast<FileUnit *>();
     silMod->getSILLoader()->getAllForModule(silMod->getSwiftModule()->getName(),
                                             primary);
   }

lib/Serialization/DeserializeSIL.cpp

@@ -597,7 +597,13 @@ SILDeserializer::readSILFunctionChecked(DeclID FID, SILFunction *existingFn,
 
     fn->setSerialized(IsSerialized_t(isSerialized));
 
-    if (SILMod.getOptions().MergePartialModules)
+    // If the serialized function comes from the same module, we're merging
+    // modules, and can update the the linkage directly. This is needed to
+    // correctly update the linkage for forward declarations to entities defined
+    // in another file of the same module – we want to ensure the linkage
+    // reflects the fact that the entity isn't really external and shouldn't be
+    // dropped from the resulting merged module.
+    if (getFile()->getParentModule() == SILMod.getSwiftModule())
       fn->setLinkage(linkage);
 
     // Don't override the transparency or linkage of a function with