SIL: Sink GenericContextScope into IRGen.

jckarter · jckarter · commit 0926d2380bf2 · 2019-12-02T12:20:05.000-08:00
All the context dependencies in SIL type lowering have been eradicated, but IRGen's
type info lowering is still context-dependent and doesn't systemically pass generic
contexts around. Sink GenericContextScope bookkeeping entirely into IRGen for now.
diff --git a/include/swift/SIL/TypeLowering.h b/include/swift/SIL/TypeLowering.h
@@ -654,20 +654,6 @@ class TypeConverter {
   /// Mapping for types independent on contextual generic parameters.
   llvm::DenseMap<CachingTypeKey, const TypeLowering *> LoweredTypes;
 
-  struct DependentTypeState {
-    CanGenericSignature Sig;
-
-    explicit DependentTypeState(CanGenericSignature sig) : Sig(sig) {}
-
-    DependentTypeState(DependentTypeState &&) = default;
-
-    // No copy constructor or assignment.
-    DependentTypeState(const DependentTypeState &) = delete;
-    void operator=(const DependentTypeState &) = delete;
-  };
-
-  llvm::SmallVector<DependentTypeState, 1> DependentTypes;
-
   llvm::DenseMap<std::pair<TypeExpansionContext, SILDeclRef>, SILConstantInfo *>
       ConstantTypes;
 
@@ -950,26 +936,6 @@ class TypeConverter {
                                     AbstractStorageDecl *value,
                                     Type lvalueType);
 
-  /// Push a generic function context. See GenericContextScope for an RAII
-  /// interface to this function.
-  ///
-  /// Types containing generic parameter references must be lowered in a generic
-  /// context. There can be at most one level of generic context active at any
-  /// point in time.
-  void pushGenericContext(CanGenericSignature sig);
-
-  /// Return the current generic context.  This should only be used in
-  /// the type-conversion routines.
-  CanGenericSignature getCurGenericContext() const {
-    if (DependentTypes.empty())
-      return CanGenericSignature();
-    return DependentTypes.back().Sig;
-  }
-  
-  /// Pop a generic function context. See GenericContextScope for an RAII
-  /// interface to this function. There must be an active generic context.
-  void popGenericContext(CanGenericSignature sig);
-  
   /// Known types for bridging.
 #define BRIDGING_KNOWN_TYPE(BridgedModule,BridgedType) \
   CanType get##BridgedType##Type();
@@ -1080,26 +1046,6 @@ class TypeConverter {
                                bool suppressOptional);
 };
 
-/// RAII interface to push a generic context.
-class GenericContextScope {
-  TypeConverter &TC;
-  CanGenericSignature Sig;
-public:
-  GenericContextScope(TypeConverter &TC, CanGenericSignature sig)
-    : TC(TC), Sig(sig)
-  {
-    TC.pushGenericContext(sig);
-  }
-  
-  ~GenericContextScope() {
-    TC.popGenericContext(Sig);
-  }
-  
-private:
-  GenericContextScope(const GenericContextScope&) = delete;
-  GenericContextScope &operator=(const GenericContextScope&) = delete;
-};
-
 } // namespace Lowering
 } // namespace swift
 
diff --git a/lib/IRGen/GenType.cpp b/lib/IRGen/GenType.cpp
@@ -1262,13 +1262,11 @@ TypeConverter::~TypeConverter() {
   }
 }
 
-void TypeConverter::pushGenericContext(CanGenericSignature signature) {
+void TypeConverter::setGenericContext(CanGenericSignature signature) {
   if (!signature)
     return;
   
-  // Push the generic context down to the SIL TypeConverter, so we can share
-  // archetypes with SIL.
-  IGM.getSILTypes().pushGenericContext(signature);
+  CurGenericSignature = signature;
 
   // Clear the dependent type info cache since we have a new active signature
   // now.
@@ -1277,21 +1275,12 @@ void TypeConverter::pushGenericContext(CanGenericSignature signature) {
   Types.getCacheFor(/*isDependent*/ true, Mode::CompletelyFragile).clear();
 }
 
-void TypeConverter::popGenericContext(CanGenericSignature signature) {
-  if (!signature)
-    return;
-
-  // Pop the SIL TypeConverter's generic context too.
-  IGM.getSILTypes().popGenericContext(signature);
-  
-  Types.getCacheFor(/*isDependent*/ true, Mode::Normal).clear();
-  Types.getCacheFor(/*isDependent*/ true, Mode::Legacy).clear();
-  Types.getCacheFor(/*isDependent*/ true, Mode::CompletelyFragile).clear();
+CanGenericSignature IRGenModule::getCurGenericContext() {
+  return Types.getCurGenericContext();
 }
 
 GenericEnvironment *TypeConverter::getGenericEnvironment() {
-  auto genericSig = IGM.getSILTypes().getCurGenericContext();
-  return genericSig->getCanonicalSignature()->getGenericEnvironment();
+  return CurGenericSignature->getGenericEnvironment();
 }
 
 GenericEnvironment *IRGenModule::getGenericEnvironment() {
diff --git a/lib/IRGen/GenType.h b/lib/IRGen/GenType.h
@@ -53,6 +53,7 @@ namespace swift {
   
 namespace irgen {
   class Alignment;
+  class GenericContextScope;
   class ProtocolInfo;
   class Size;
   class FixedTypeInfo;
@@ -86,6 +87,13 @@ class TypeConverter {
 
   IRGenModule &IGM;
 private:
+  // Set using the GenericContextScope RAII object.
+  friend GenericContextScope;
+  CanGenericSignature CurGenericSignature;
+  // Enter a generic context for lowering the parameters of a generic function
+  // type.
+  void setGenericContext(CanGenericSignature signature);
+
   Mode LoweringMode = Mode::Normal;
 
   llvm::DenseMap<ProtocolDecl*, std::unique_ptr<const ProtocolInfo>> Protocols;
@@ -187,13 +195,10 @@ class TypeConverter {
 
   llvm::Type *getExistentialType(unsigned numWitnessTables);
 
-  /// Enter a generic context for lowering the parameters of a generic function
-  /// type.
-  void pushGenericContext(CanGenericSignature signature);
+  /// Retrieve the generic signature for the current generic context, or null if no
+  /// generic environment is active.
+  CanGenericSignature getCurGenericContext() { return CurGenericSignature; }
   
-  /// Exit a generic context.
-  void popGenericContext(CanGenericSignature signature);
-
   /// Retrieve the generic environment for the current generic context.
   ///
   /// Fails if there is no generic context.
@@ -235,20 +240,23 @@ class TypeConverter {
 /// a scope.
 class GenericContextScope {
   TypeConverter &TC;
-  CanGenericSignature sig;
+  CanGenericSignature newSig, oldSig;
 public:
   GenericContextScope(TypeConverter &TC, CanGenericSignature sig)
-    : TC(TC), sig(sig)
+    : TC(TC), newSig(sig), oldSig(TC.CurGenericSignature)
   {
-    TC.pushGenericContext(sig);
+    TC.setGenericContext(newSig);
   }
   
   GenericContextScope(IRGenModule &IGM, CanGenericSignature sig)
     : GenericContextScope(IGM.Types, sig)
   {}
   
   ~GenericContextScope() {
-    TC.popGenericContext(sig);
+    if (!newSig)
+      return;
+    assert(TC.CurGenericSignature == newSig);
+    TC.setGenericContext(oldSig);
   }
 };
 
diff --git a/lib/IRGen/IRGenDebugInfo.cpp b/lib/IRGen/IRGenDebugInfo.cpp
@@ -841,7 +841,7 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
                    llvm::DINode::DIFlags Flags, unsigned &SizeInBits) {
     SmallVector<llvm::Metadata *, 16> Elements;
     unsigned OffsetInBits = 0;
-    auto genericSig = IGM.getSILTypes().getCurGenericContext();
+    auto genericSig = IGM.getCurGenericContext();
     for (auto ElemTy : TupleTy->getElementTypes()) {
       auto &elemTI = IGM.getTypeInfoForUnlowered(
           AbstractionPattern(genericSig, ElemTy->getCanonicalType()), ElemTy);
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
@@ -858,7 +858,7 @@ class IRGenModule {
 
 private:
   TypeConverter &Types;
-  friend class TypeConverter;
+  friend TypeConverter;
 
   const clang::ASTContext *ClangASTContext;
   ClangTypeConverter *ClangTypes;
@@ -1423,6 +1423,10 @@ private:                            \
 
   Address getAddrOfObjCISAMask();
 
+  /// Retrieve the generic signature for the current generic context, or null if no
+  /// generic environment is active.
+  CanGenericSignature getCurGenericContext();
+  
   /// Retrieve the generic environment for the current generic context.
   ///
   /// Fails if there is no generic context.
diff --git a/lib/ParseSIL/ParseSIL.cpp b/lib/ParseSIL/ParseSIL.cpp
@@ -3175,9 +3175,6 @@ bool SILParser::parseSILInstruction(SILBuilder &B) {
     SmallVector<SILValue, 4> operands;
     
     if (P.consumeIf(tok::l_paren)) {
-      Lowering::GenericContextScope scope(SILMod.Types,
-        patternEnv ? patternEnv->getGenericSignature()->getCanonicalSignature()
-                   : nullptr);
       while (true) {
         SILValue v;
         
diff --git a/lib/SIL/SILType.cpp b/lib/SIL/SILType.cpp
@@ -422,7 +422,6 @@ SILResultInfo::getOwnershipKind(SILFunction &F) const {
   auto &M = F.getModule();
   auto FTy = F.getLoweredFunctionType();
   auto sig = FTy->getInvocationGenericSignature();
-  GenericContextScope GCS(M.Types, sig);
 
   bool IsTrivial = getSILStorageType(M, FTy).isTrivial(F);
   switch (getConvention()) {
diff --git a/lib/SIL/SILVerifier.cpp b/lib/SIL/SILVerifier.cpp
@@ -4478,9 +4478,6 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
             "keypath value type should match value type of keypath pattern");
     
     {
-      Lowering::GenericContextScope scope(F.getModule().Types,
-                                          pattern->getGenericSignature());
-      
       for (auto &component : pattern->getComponents()) {
         bool hasIndices;
         switch (component.getKind()) {
@@ -5130,7 +5127,6 @@ void SILProperty::verify(const SILModule &M) const {
   }
 
   auto canSig = sig ? sig->getCanonicalSignature() : nullptr;
-  Lowering::GenericContextScope scope(M.Types, canSig);
 
   auto require = [&](bool reqt, StringRef message) {
       if (!reqt) {
diff --git a/lib/SIL/TypeLowering.cpp b/lib/SIL/TypeLowering.cpp
@@ -2144,26 +2144,6 @@ SILType TypeConverter::getSubstitutedStorageType(TypeExpansionContext context,
   return SILType::getPrimitiveAddressType(substLoweredType);
 }
 
-void TypeConverter::pushGenericContext(CanGenericSignature sig) {
-  // If the generic signature is empty, this is a no-op.
-  if (!sig)
-    return;
-
-  DependentTypeState state(sig);
-  DependentTypes.push_back(std::move(state));
-}
-
-void TypeConverter::popGenericContext(CanGenericSignature sig) {
-  // If the generic signature is empty, this is a no-op.
-  if (!sig)
-    return;
-
-  DependentTypeState &state = DependentTypes.back();
-  assert(state.Sig == sig && "unpaired push/pop");
-  
-  DependentTypes.pop_back();
-}
-
 ProtocolDispatchStrategy
 TypeConverter::getProtocolDispatchStrategy(ProtocolDecl *P) {
   // ObjC protocols use ObjC method dispatch, and Swift protocols
@@ -2668,8 +2648,6 @@ TypeConverter::getInterfaceBoxTypeForCapture(ValueDecl *captured,
 
   auto boxTy = SILBoxType::get(C, layout, subMap);
 #ifndef NDEBUG
-  // FIXME: Map the box type out of context when asserting the field so
-  // we don't need to push a GenericContextScope (which really ought to die).
   auto loweredContextType = loweredInterfaceType;
   auto contextBoxTy = boxTy;
   if (signature) {
@@ -2738,7 +2716,6 @@ CanSILBoxType TypeConverter::getBoxTypeForEnumElement(
 
   // Lower the enum element's argument in the box's context.
   auto eltIntfTy = elt->getArgumentInterfaceType();
-  GenericContextScope scope(*this, boxSignature);
 
   auto boxVarTy = getLoweredRValueType(context,
                                        getAbstractionPattern(elt), eltIntfTy);
diff --git a/lib/SILGen/SILGenBridging.cpp b/lib/SILGen/SILGenBridging.cpp
@@ -229,7 +229,6 @@ emitBridgeObjectiveCToNative(SILGenFunction &SGF,
   auto subs = witness.getSubstitutions();
 
   // Set up the generic signature, since formalResultTy is an interface type.
-  GenericContextScope genericContextScope(SGF.SGM.Types, genericSig);
   CalleeTypeInfo calleeTypeInfo(
       witnessFnTy,
       AbstractionPattern(genericSig, formalResultTy),
diff --git a/lib/SILGen/SILGenExpr.cpp b/lib/SILGen/SILGenExpr.cpp
@@ -2796,7 +2796,6 @@ static SILFunction *getOrCreateKeyPathSetter(SILGenModule &SGM,
   // Build the signature of the thunk as expected by the keypath runtime.
   CanType loweredBaseTy, loweredPropTy;
   {
-    GenericContextScope scope(SGM.Types, genericSig);
     AbstractionPattern opaque = AbstractionPattern::getOpaque();
 
     loweredBaseTy = SGM.Types.getLoweredRValueType(
diff --git a/lib/SILOptimizer/IPO/CapturePromotion.cpp b/lib/SILOptimizer/IPO/CapturePromotion.cpp
@@ -337,10 +337,7 @@ computeNewArgInterfaceTypes(SILFunction *F, IndicesSet &PromotableIndices,
 
   LLVM_DEBUG(llvm::dbgs() << "Preparing New Args!\n");
 
-  auto fnTy = F->getLoweredFunctionType();
-
   auto &Types = F->getModule().Types;
-  Lowering::GenericContextScope scope(Types, fnTy->getInvocationGenericSignature());
 
   // For each parameter in the old function...
   for (unsigned Index : indices(Parameters)) {
diff --git a/lib/SILOptimizer/Mandatory/AddressLowering.cpp b/lib/SILOptimizer/Mandatory/AddressLowering.cpp
@@ -388,15 +388,6 @@ class OpaqueStorageAllocation {
 
 /// Top-level entry point: allocate storage for all opaque/resilient values.
 void OpaqueStorageAllocation::allocateOpaqueStorage() {
-  // TODO: I think we need a GenericContextScope for mapTypeIntoContext, but all
-  // tests are currently passing without it.
-#if 0
-  auto canFnType = pass.F->getLoweredFunctionType();
-
-  // Setup a generic context for argument and result types.
-  swift::Lowering::GenericContextScope scope(pass.F->getModule().Types,
-                                             canFnType->getGenericSignature());
-#endif
   // Fixup this function's argument types with temporary loads.
   convertIndirectFunctionArgs();
 
diff --git a/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp b/lib/SILOptimizer/Transforms/AllocBoxToStack.cpp
@@ -584,8 +584,6 @@ SILFunction *PromotedParamCloner::initCloned(SILOptFunctionBuilder &FuncBuilder,
       SILType paramTy;
       {
         auto &TC = Orig->getModule().Types;
-        Lowering::GenericContextScope scope(TC,
-                                      OrigFTI->getSubstGenericSignature());
         paramTy = getSILBoxFieldType(TypeExpansionContext(*Orig), boxTy, TC, 0);
       }
       auto promotedParam = SILParameterInfo(paramTy.getASTType(),
diff --git a/lib/SILOptimizer/Utils/Generics.cpp b/lib/SILOptimizer/Utils/Generics.cpp
@@ -676,7 +676,6 @@ void ReabstractionInfo::createSubstitutedAndSpecializedTypes() {
   CanGenericSignature CanSig;
   if (SpecializedGenericSig)
     CanSig = SpecializedGenericSig->getCanonicalSignature();
-  Lowering::GenericContextScope GenericScope(M.Types, CanSig);
 
   SILFunctionConventions substConv(SubstitutedType, M);
 
@@ -759,8 +758,6 @@ ReabstractionInfo::createSubstitutedType(SILFunction *OrigF,
   // First substitute concrete types into the existing function type.
   CanSILFunctionType FnTy;
   {
-    Lowering::GenericContextScope GenericScope(M.Types,
-                                               CanSpecializedGenericSig);
     FnTy = OrigF->getLoweredFunctionType()->substGenericArgs(
         M, SubstMap, getResilienceExpansion());
     // FIXME: Some of the added new requirements may not have been taken into
@@ -2092,11 +2089,6 @@ SILFunction *ReabstractionThunkGenerator::createThunk() {
 
   Thunk->setGenericEnvironment(ReInfo.getSpecializedGenericEnvironment());
 
-  // Set proper generic context scope for the type lowering.
-  CanSILFunctionType SpecType = SpecializedFunc->getLoweredFunctionType();
-  Lowering::GenericContextScope GenericScope(M.Types,
-                                     SpecType->getInvocationGenericSignature());
-
   SILBasicBlock *EntryBB = Thunk->createBasicBlock();
   SILBuilder Builder(EntryBB);
 

Original file line number	Diff line number	Diff line change
`@@ -4478,9 +4478,6 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {`
`4478`	`4478`	`"keypath value type should match value type of keypath pattern");`
`4479`	`4479`
`4480`	`4480`	`{`
`4481`		`- Lowering::GenericContextScope scope(F.getModule().Types,`
`4482`		`- pattern->getGenericSignature());`
`4483`		`-`
`4484`	`4481`	`for (auto &component : pattern->getComponents()) {`
`4485`	`4482`	`bool hasIndices;`
`4486`	`4483`	`switch (component.getKind()) {`
`@@ -5130,7 +5127,6 @@ void SILProperty::verify(const SILModule &M) const {`
`5130`	`5127`	`}`
`5131`	`5128`
`5132`	`5129`	`auto canSig = sig ? sig->getCanonicalSignature() : nullptr;`
`5133`		`- Lowering::GenericContextScope scope(M.Types, canSig);`
`5134`	`5130`
`5135`	`5131`	`auto require = [&](bool reqt, StringRef message) {`
`5136`	`5132`	`if (!reqt) {`