[AutoDiff] NFC: gardening.

include/swift/AST/ASTMangler.h

@@ -172,6 +172,19 @@ class ASTMangler : public Mangler {
                                             AutoDiffLinearMapKind kind,
                                             AutoDiffConfig config);
 
+  /// Mangle the AutoDiff generated declaration for the given:
+  /// - Generated declaration kind: linear map struct or branching trace enum.
+  /// - Mangled original function name.
+  /// - Basic block number.
+  /// - Linear map kind: differential or pullback.
+  /// - Derivative function configuration: parameter/result indices and
+  ///   derivative generic signature.
+  std::string
+  mangleAutoDiffGeneratedDeclaration(AutoDiffGeneratedDeclarationKind declKind,
+                                     StringRef origFnName, unsigned bbId,
+                                     AutoDiffLinearMapKind linearMapKind,
+                                     AutoDiffConfig config);
+
   /// Mangle a SIL differentiability witness key:
   /// - Mangled original function name.
   /// - Parameter indices.

include/swift/AST/AutoDiff.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2019 Apple Inc. and the Swift project authors
+// Copyright (c) 2019 - 2020 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -31,6 +31,7 @@
 namespace swift {
 
 class AnyFunctionType;
+class SourceFile;
 class SILFunctionType;
 class TupleType;
 
@@ -164,6 +165,12 @@ struct DifferentiabilityWitnessFunctionKind {
   Optional<AutoDiffDerivativeFunctionKind> getAsDerivativeFunctionKind() const;
 };
 
+/// The kind of a declaration generated by the differentiation transform.
+enum class AutoDiffGeneratedDeclarationKind : uint8_t {
+  LinearMapStruct,
+  BranchingTraceEnum
+};
+
 /// SIL-level automatic differentiation indices. Consists of:
 /// - Parameter indices: indices of parameters to differentiate with respect to.
 /// - Result index: index of the result to differentiate from.
@@ -386,6 +393,9 @@ class TangentSpace {
 /// derivative generic signature.
 using SILDifferentiabilityWitnessKey = std::pair<StringRef, AutoDiffConfig>;
 
+/// Returns `true` iff differentiable programming is enabled.
+bool isDifferentiableProgrammingEnabled(SourceFile &SF);
+
 /// Automatic differentiation utility namespace.
 namespace autodiff {
 

include/swift/SILOptimizer/Utils/Differentiation/LinearMapInfo.h

@@ -113,30 +113,26 @@ class LinearMapInfo {
   /// whose cases represent the predecessors/successors of the given original
   /// block.
   EnumDecl *createBranchingTraceDecl(SILBasicBlock *originalBB,
-                                     SILAutoDiffIndices indices,
                                      CanGenericSignature genericSig,
                                      SILLoopInfo *loopInfo);
 
   /// Creates a struct declaration with the given JVP/VJP generic signature, for
   /// storing the linear map values and predecessor/successor basic block of the
   /// given original block.
   StructDecl *createLinearMapStruct(SILBasicBlock *originalBB,
-                                    SILAutoDiffIndices indices,
                                     CanGenericSignature genericSig);
 
   /// Adds a linear map field to the linear map struct.
   VarDecl *addLinearMapDecl(ApplyInst *ai, SILType linearMapType);
 
   /// Given an `apply` instruction, conditionally adds a linear map struct field
   /// for its linear map function if it is active.
-  void addLinearMapToStruct(ADContext &context, ApplyInst *ai,
-                            SILAutoDiffIndices indices);
+  void addLinearMapToStruct(ADContext &context, ApplyInst *ai);
 
   /// Generates linear map struct and branching enum declarations for the given
   /// function. Linear map structs are populated with linear map fields and a
   /// branching enum field.
   void generateDifferentiationDataStructures(ADContext &context,
-                                             SILAutoDiffIndices indices,
                                              SILFunction *derivative);
 
 public:

lib/AST/ASTMangler.cpp

@@ -424,6 +424,45 @@ std::string ASTMangler::mangleAutoDiffLinearMapHelper(
   return result;
 }
 
+std::string ASTMangler::mangleAutoDiffGeneratedDeclaration(
+    AutoDiffGeneratedDeclarationKind declKind, StringRef origFnName,
+    unsigned bbId, AutoDiffLinearMapKind linearMapKind, AutoDiffConfig config) {
+  beginManglingWithoutPrefix();
+
+  Buffer << "_AD__" << origFnName << "_bb" + std::to_string(bbId);
+  switch (declKind) {
+  case AutoDiffGeneratedDeclarationKind::LinearMapStruct:
+    switch (linearMapKind) {
+    case AutoDiffLinearMapKind::Differential:
+      Buffer << "__DF__";
+      break;
+    case AutoDiffLinearMapKind::Pullback:
+      Buffer << "__PB__";
+      break;
+    }
+    break;
+  case AutoDiffGeneratedDeclarationKind::BranchingTraceEnum:
+    switch (linearMapKind) {
+    case AutoDiffLinearMapKind::Differential:
+      Buffer << "__Succ__";
+      break;
+    case AutoDiffLinearMapKind::Pullback:
+      Buffer << "__Pred__";
+      break;
+    }
+    break;
+  }
+  Buffer << config.getSILAutoDiffIndices().mangle();
+  if (config.derivativeGenericSignature) {
+    Buffer << '_';
+    appendGenericSignature(config.derivativeGenericSignature);
+  }
+
+  auto result = Storage.str().str();
+  Storage.clear();
+  return result;
+}
+
 std::string ASTMangler::mangleSILDifferentiabilityWitnessKey(
     SILDifferentiabilityWitnessKey key) {
   // TODO(TF-20): Make the mangling scheme robust. Support demangling.

lib/AST/AutoDiff.cpp

@@ -13,6 +13,7 @@
 #include "swift/AST/AutoDiff.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/GenericEnvironment.h"
+#include "swift/AST/ImportCache.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/TypeCheckRequests.h"
 #include "swift/AST/Types.h"
@@ -124,6 +125,23 @@ void AutoDiffConfig::print(llvm::raw_ostream &s) const {
   s << ')';
 }
 
+bool swift::isDifferentiableProgrammingEnabled(SourceFile &SF) {
+  auto &ctx = SF.getASTContext();
+  // Return true if differentiable programming is explicitly enabled.
+  if (ctx.LangOpts.EnableExperimentalDifferentiableProgramming)
+    return true;
+  // Otherwise, return true iff the `_Differentiation` module is imported in
+  // the given source file.
+  bool importsDifferentiationModule = false;
+  for (auto import : namelookup::getAllImports(&SF)) {
+    if (import.second->getName() == ctx.Id_Differentiation) {
+      importsDifferentiationModule = true;
+      break;
+    }
+  }
+  return importsDifferentiationModule;
+}
+
 // TODO(TF-874): This helper is inefficient and should be removed. Unwrapping at
 // most once (for curried method types) is sufficient.
 static void unwrapCurryLevels(AnyFunctionType *fnTy,

lib/SILOptimizer/Utils/Differentiation/LinearMapInfo.cpp

@@ -59,7 +59,7 @@ LinearMapInfo::LinearMapInfo(ADContext &context, AutoDiffLinearMapKind kind,
     : kind(kind), original(original), derivative(derivative),
       activityInfo(activityInfo), indices(indices),
       typeConverter(context.getTypeConverter()) {
-  generateDifferentiationDataStructures(context, indices, derivative);
+  generateDifferentiationDataStructures(context, derivative);
 }
 
 SILType LinearMapInfo::remapTypeInDerivative(SILType ty) {
@@ -122,27 +122,24 @@ void LinearMapInfo::computeAccessLevel(NominalTypeDecl *nominal,
   }
 }
 
-EnumDecl *LinearMapInfo::createBranchingTraceDecl(
-    SILBasicBlock *originalBB, SILAutoDiffIndices indices,
-    CanGenericSignature genericSig, SILLoopInfo *loopInfo) {
+EnumDecl *
+LinearMapInfo::createBranchingTraceDecl(SILBasicBlock *originalBB,
+                                        CanGenericSignature genericSig,
+                                        SILLoopInfo *loopInfo) {
   assert(originalBB->getParent() == original);
   auto &astCtx = original->getASTContext();
   auto *moduleDecl = original->getModule().getSwiftModule();
   auto &file = getDeclarationFileUnit();
   // Create a branching trace enum.
-  std::string enumName;
-  switch (kind) {
-  case AutoDiffLinearMapKind::Differential:
-    enumName = "_AD__" + original->getName().str() + "_bb" +
-               std::to_string(originalBB->getDebugID()) + "__Succ__" +
-               indices.mangle();
-    break;
-  case AutoDiffLinearMapKind::Pullback:
-    enumName = "_AD__" + original->getName().str() + "_bb" +
-               std::to_string(originalBB->getDebugID()) + "__Pred__" +
-               indices.mangle();
-    break;
-  }
+  Mangle::ASTMangler mangler;
+  auto *resultIndices = IndexSubset::get(
+      original->getASTContext(),
+      original->getLoweredFunctionType()->getNumResults(), indices.source);
+  auto *parameterIndices = indices.parameters;
+  AutoDiffConfig config(parameterIndices, resultIndices, genericSig);
+  auto enumName = mangler.mangleAutoDiffGeneratedDeclaration(
+      AutoDiffGeneratedDeclarationKind::BranchingTraceEnum,
+      original->getName().str(), originalBB->getDebugID(), kind, config);
   auto enumId = astCtx.getIdentifier(enumName);
   auto loc = original->getLocation().getSourceLoc();
   GenericParamList *genericParams = nullptr;
@@ -199,25 +196,21 @@ EnumDecl *LinearMapInfo::createBranchingTraceDecl(
 
 StructDecl *
 LinearMapInfo::createLinearMapStruct(SILBasicBlock *originalBB,
-                                     SILAutoDiffIndices indices,
                                      CanGenericSignature genericSig) {
   assert(originalBB->getParent() == original);
   auto *original = originalBB->getParent();
   auto &astCtx = original->getASTContext();
   auto &file = getDeclarationFileUnit();
-  std::string structName;
-  switch (kind) {
-  case swift::AutoDiffLinearMapKind::Differential:
-    structName = "_AD__" + original->getName().str() + "_bb" +
-                 std::to_string(originalBB->getDebugID()) + "__DF__" +
-                 indices.mangle();
-    break;
-  case swift::AutoDiffLinearMapKind::Pullback:
-    structName = "_AD__" + original->getName().str() + "_bb" +
-                 std::to_string(originalBB->getDebugID()) + "__PB__" +
-                 indices.mangle();
-    break;
-  }
+  // Create a linear map struct.
+  Mangle::ASTMangler mangler;
+  auto *resultIndices = IndexSubset::get(
+      original->getASTContext(),
+      original->getLoweredFunctionType()->getNumResults(), indices.source);
+  auto *parameterIndices = indices.parameters;
+  AutoDiffConfig config(parameterIndices, resultIndices, genericSig);
+  auto structName = mangler.mangleAutoDiffGeneratedDeclaration(
+      AutoDiffGeneratedDeclarationKind::LinearMapStruct,
+      original->getName().str(), originalBB->getDebugID(), kind, config);
   auto structId = astCtx.getIdentifier(structName);
   GenericParamList *genericParams = nullptr;
   if (genericSig)
@@ -274,8 +267,7 @@ VarDecl *LinearMapInfo::addLinearMapDecl(ApplyInst *ai, SILType linearMapType) {
   return linearMapDecl;
 }
 
-void LinearMapInfo::addLinearMapToStruct(ADContext &context, ApplyInst *ai,
-                                         SILAutoDiffIndices indices) {
+void LinearMapInfo::addLinearMapToStruct(ADContext &context, ApplyInst *ai) {
   SmallVector<SILValue, 4> allResults;
   SmallVector<unsigned, 8> activeParamIndices;
   SmallVector<unsigned, 8> activeResultIndices;
@@ -379,7 +371,7 @@ void LinearMapInfo::addLinearMapToStruct(ADContext &context, ApplyInst *ai,
 }
 
 void LinearMapInfo::generateDifferentiationDataStructures(
-    ADContext &context, SILAutoDiffIndices indices, SILFunction *derivativeFn) {
+    ADContext &context, SILFunction *derivativeFn) {
   auto &astCtx = original->getASTContext();
   auto *loopAnalysis = context.getPassManager().getAnalysis<SILLoopAnalysis>();
   auto *loopInfo = loopAnalysis->get(original);
@@ -392,8 +384,7 @@ void LinearMapInfo::generateDifferentiationDataStructures(
 
   // Create linear map struct for each original block.
   for (auto &origBB : *original) {
-    auto *linearMapStruct =
-        createLinearMapStruct(&origBB, indices, derivativeFnGenSig);
+    auto *linearMapStruct = createLinearMapStruct(&origBB, derivativeFnGenSig);
     linearMapStructs.insert({&origBB, linearMapStruct});
   }
 
@@ -409,8 +400,8 @@ void LinearMapInfo::generateDifferentiationDataStructures(
     break;
   }
   for (auto &origBB : *original) {
-    auto *traceEnum = createBranchingTraceDecl(&origBB, indices,
-                                               derivativeFnGenSig, loopInfo);
+    auto *traceEnum =
+        createBranchingTraceDecl(&origBB, derivativeFnGenSig, loopInfo);
     branchingTraceDecls.insert({&origBB, traceEnum});
     if (origBB.isEntry())
       continue;
@@ -433,7 +424,7 @@ void LinearMapInfo::generateDifferentiationDataStructures(
           continue;
         LLVM_DEBUG(getADDebugStream()
                    << "Adding linear map struct field for " << *ai);
-        addLinearMapToStruct(context, ai, indices);
+        addLinearMapToStruct(context, ai);
       }
     }
   }

lib/Sema/TypeChecker.cpp

@@ -410,23 +410,6 @@ void swift::performWholeModuleTypeChecking(SourceFile &SF) {
 #endif
 }
 
-bool swift::isDifferentiableProgrammingEnabled(SourceFile &SF) {
-  auto &ctx = SF.getASTContext();
-  // Return true if differentiable programming is explicitly enabled.
-  if (ctx.LangOpts.EnableExperimentalDifferentiableProgramming)
-    return true;
-  // Otherwise, return true iff the `_Differentiation` module is imported in
-  // the given source file.
-  bool importsDifferentiationModule = false;
-  for (auto import : namelookup::getAllImports(&SF)) {
-    if (import.second->getName() == ctx.Id_Differentiation) {
-      importsDifferentiationModule = true;
-      break;
-    }
-  }
-  return importsDifferentiationModule;
-}
-
 bool swift::isAdditiveArithmeticConformanceDerivationEnabled(SourceFile &SF) {
   auto &ctx = SF.getASTContext();
   // Return true if `AdditiveArithmetic` derived conformances are explicitly

lib/Sema/TypeChecker.h

@@ -1520,9 +1520,6 @@ bool isMemberOperator(FuncDecl *decl, Type type);
 /// Complain if @objc or dynamic is used without importing Foundation.
 void diagnoseAttrsRequiringFoundation(SourceFile &SF);
 
-/// Returns `true` iff differentiable programming is enabled.
-bool isDifferentiableProgrammingEnabled(SourceFile &SF);
-
 /// Returns `true` iff `AdditiveArithmetic` derived conformances are enabled.
 bool isAdditiveArithmeticConformanceDerivationEnabled(SourceFile &SF);