llvm/lib/Transforms/Coroutines/CoroInternal.h

   1 //===- CoroInternal.h - Internal Coroutine interfaces ---------*- C++ -*---===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 // Common definitions/declarations used internally by coroutine lowering passes.
   9 //===----------------------------------------------------------------------===//
  10
  11 #ifndef LLVM_LIB_TRANSFORMS_COROUTINES_COROINTERNAL_H
  12 #define LLVM_LIB_TRANSFORMS_COROUTINES_COROINTERNAL_H
  13
  14 #include "CoroInstr.h"
  15 #include "llvm/IR/IRBuilder.h"
  16 #include "llvm/Transforms/Coroutines.h"
  17
  18 namespace llvm {
  19
  20 class CallGraph;
  21 class CallGraphSCC;
  22 class PassRegistry;
  23
  24 void initializeCoroEarlyLegacyPass(PassRegistry &);
  25 void initializeCoroSplitLegacyPass(PassRegistry &);
  26 void initializeCoroElideLegacyPass(PassRegistry &);
  27 void initializeCoroCleanupLegacyPass(PassRegistry &);
  28
  29 // CoroEarly pass marks every function that has coro.begin with a string
  30 // attribute "coroutine.presplit"="0". CoroSplit pass processes the coroutine
  31 // twice. First, it lets it go through complete IPO optimization pipeline as a
  32 // single function. It forces restart of the pipeline by inserting an indirect
  33 // call to an empty function "coro.devirt.trigger" which is devirtualized by
  34 // CoroElide pass that triggers a restart of the pipeline by CGPassManager.
  35 // When CoroSplit pass sees the same coroutine the second time, it splits it up,
  36 // adds coroutine subfunctions to the SCC to be processed by IPO pipeline.
  37
  38 #define CORO_PRESPLIT_ATTR "coroutine.presplit"
  39 #define UNPREPARED_FOR_SPLIT "0"
  40 #define PREPARED_FOR_SPLIT "1"
  41
  42 #define CORO_DEVIRT_TRIGGER_FN "coro.devirt.trigger"
  43
  44 namespace coro {
  45
  46 bool declaresIntrinsics(const Module &M,
  47                         const std::initializer_list<StringRef>);
  48 void replaceAllCoroAllocs(CoroBeginInst *CB, bool Replacement);
  49 void replaceAllCoroFrees(CoroBeginInst *CB, Value *Replacement);
  50 void replaceCoroFree(CoroIdInst *CoroId, bool Elide);
  51 void updateCallGraph(Function &Caller, ArrayRef<Function *> Funcs,
  52                      CallGraph &CG, CallGraphSCC &SCC);
  53
  54 // Keeps data and helper functions for lowering coroutine intrinsics.
  55 struct LowererBase {
  56   Module &TheModule;
  57   LLVMContext &Context;
  58   PointerType *const Int8Ptr;
  59   FunctionType *const ResumeFnType;
  60   ConstantPointerNull *const NullPtr;
  61
  62   LowererBase(Module &M);
  63   Value *makeSubFnCall(Value *Arg, int Index, Instruction *InsertPt);
  64 };
  65
  66 enum class ABI {
  67   /// The "resume-switch" lowering, where there are separate resume and
  68   /// destroy functions that are shared between all suspend points.  The
  69   /// coroutine frame implicitly stores the resume and destroy functions,
  70   /// the current index, and any promise value.
  71   Switch,
  72
  73   /// The "returned-continuation" lowering, where each suspend point creates a
  74   /// single continuation function that is used for both resuming and
  75   /// destroying.  Does not support promises.
  76   Retcon,
  77
  78   /// The "unique returned-continuation" lowering, where each suspend point
  79   /// creates a single continuation function that is used for both resuming
  80   /// and destroying.  Does not support promises.  The function is known to
  81   /// suspend at most once during its execution, and the return value of
  82   /// the continuation is void.
  83   RetconOnce,
  84 };
  85
  86 // Holds structural Coroutine Intrinsics for a particular function and other
  87 // values used during CoroSplit pass.
  88 struct LLVM_LIBRARY_VISIBILITY Shape {
  89   CoroBeginInst *CoroBegin;
  90   SmallVector<CoroEndInst *, 4> CoroEnds;
  91   SmallVector<CoroSizeInst *, 2> CoroSizes;
  92   SmallVector<AnyCoroSuspendInst *, 4> CoroSuspends;
  93   SmallVector<CallInst*, 2> SwiftErrorOps;
  94
  95   // Field indexes for special fields in the switch lowering.
  96   struct SwitchFieldIndex {
  97     enum {
  98       Resume,
  99       Destroy,
 100       Promise,
 101       Index,
 102       /// The index of the first spill field.
 103       FirstSpill
 104     };
 105   };
 106
 107   coro::ABI ABI;
 108
 109   StructType *FrameTy;
 110   Instruction *FramePtr;
 111   BasicBlock *AllocaSpillBlock;
 112
 113   struct SwitchLoweringStorage {
 114     SwitchInst *ResumeSwitch;
 115     AllocaInst *PromiseAlloca;
 116     BasicBlock *ResumeEntryBlock;
 117     bool HasFinalSuspend;
 118   };
 119
 120   struct RetconLoweringStorage {
 121     Function *ResumePrototype;
 122     Function *Alloc;
 123     Function *Dealloc;
 124     BasicBlock *ReturnBlock;
 125     bool IsFrameInlineInStorage;
 126   };
 127
 128   union {
 129     SwitchLoweringStorage SwitchLowering;
 130     RetconLoweringStorage RetconLowering;
 131   };
 132
 133   CoroIdInst *getSwitchCoroId() const {
 134     assert(ABI == coro::ABI::Switch);
 135     return cast<CoroIdInst>(CoroBegin->getId());
 136   }
 137
 138   AnyCoroIdRetconInst *getRetconCoroId() const {
 139     assert(ABI == coro::ABI::Retcon ||
 140            ABI == coro::ABI::RetconOnce);
 141     return cast<AnyCoroIdRetconInst>(CoroBegin->getId());
 142   }
 143
 144   IntegerType *getIndexType() const {
 145     assert(ABI == coro::ABI::Switch);
 146     assert(FrameTy && "frame type not assigned");
 147     return cast<IntegerType>(FrameTy->getElementType(SwitchFieldIndex::Index));
 148   }
 149   ConstantInt *getIndex(uint64_t Value) const {
 150     return ConstantInt::get(getIndexType(), Value);
 151   }
 152
 153   PointerType *getSwitchResumePointerType() const {
 154     assert(ABI == coro::ABI::Switch);
 155   assert(FrameTy && "frame type not assigned");
 156   return cast<PointerType>(FrameTy->getElementType(SwitchFieldIndex::Resume));
 157   }
 158
 159   FunctionType *getResumeFunctionType() const {
 160     switch (ABI) {
 161     case coro::ABI::Switch: {
 162       auto *FnPtrTy = getSwitchResumePointerType();
 163       return cast<FunctionType>(FnPtrTy->getPointerElementType());
 164     }
 165     case coro::ABI::Retcon:
 166     case coro::ABI::RetconOnce:
 167       return RetconLowering.ResumePrototype->getFunctionType();
 168     }
 169     llvm_unreachable("Unknown coro::ABI enum");
 170   }
 171
 172   ArrayRef<Type*> getRetconResultTypes() const {
 173     assert(ABI == coro::ABI::Retcon ||
 174            ABI == coro::ABI::RetconOnce);
 175     auto FTy = CoroBegin->getFunction()->getFunctionType();
 176
 177     // The safety of all this is checked by checkWFRetconPrototype.
 178     if (auto STy = dyn_cast<StructType>(FTy->getReturnType())) {
 179       return STy->elements().slice(1);
 180     } else {
 181       return ArrayRef<Type*>();
 182     }
 183   }
 184
 185   ArrayRef<Type*> getRetconResumeTypes() const {
 186     assert(ABI == coro::ABI::Retcon ||
 187            ABI == coro::ABI::RetconOnce);
 188
 189     // The safety of all this is checked by checkWFRetconPrototype.
 190     auto FTy = RetconLowering.ResumePrototype->getFunctionType();
 191     return FTy->params().slice(1);
 192   }
 193
 194   CallingConv::ID getResumeFunctionCC() const {
 195     switch (ABI) {
 196     case coro::ABI::Switch:
 197       return CallingConv::Fast;
 198
 199     case coro::ABI::Retcon:
 200     case coro::ABI::RetconOnce:
 201       return RetconLowering.ResumePrototype->getCallingConv();
 202     }
 203     llvm_unreachable("Unknown coro::ABI enum");
 204   }
 205
 206   unsigned getFirstSpillFieldIndex() const {
 207     switch (ABI) {
 208     case coro::ABI::Switch:
 209       return SwitchFieldIndex::FirstSpill;
 210
 211     case coro::ABI::Retcon:
 212     case coro::ABI::RetconOnce:
 213       return 0;
 214     }
 215     llvm_unreachable("Unknown coro::ABI enum");
 216   }
 217
 218   AllocaInst *getPromiseAlloca() const {
 219     if (ABI == coro::ABI::Switch)
 220       return SwitchLowering.PromiseAlloca;
 221     return nullptr;
 222   }
 223
 224   /// Allocate memory according to the rules of the active lowering.
 225   ///
 226   /// \param CG - if non-null, will be updated for the new call
 227   Value *emitAlloc(IRBuilder<> &Builder, Value *Size, CallGraph *CG) const;
 228
 229   /// Deallocate memory according to the rules of the active lowering.
 230   ///
 231   /// \param CG - if non-null, will be updated for the new call
 232   void emitDealloc(IRBuilder<> &Builder, Value *Ptr, CallGraph *CG) const;
 233
 234   Shape() = default;
 235   explicit Shape(Function &F) { buildFrom(F); }
 236   void buildFrom(Function &F);
 237 };
 238
 239 void buildCoroutineFrame(Function &F, Shape &Shape);
 240
 241 } // End namespace coro.
 242 } // End namespace llvm
 243
 244 #endif