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https://github.com/apple/swift.git
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99 lines
2.8 KiB
C++
99 lines
2.8 KiB
C++
#include "swift/SILAnalysis/DestructorAnalysis.h"
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#include "swift/SIL/SILInstruction.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/Decl.h"
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#include "swift/SIL/SILModule.h"
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#include "llvm/Support/Debug.h"
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#define DEBUG_TYPE "destructor-analysis"
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using namespace swift;
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/// A type T's destructor does not store to memory if the type
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/// * is a trivial builtin type like builtin float or int types
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/// * is a value type with stored properties that are safe or
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/// * is a value type that implements the _DestructorSafeContainer protocol and
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/// whose type parameters are safe types T1...Tn.
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bool DestructorAnalysis::mayStoreToMemoryOnDestruction(SILType T) {
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bool IsSafe = isSafeType(T.getSwiftRValueType());
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DEBUG(llvm::dbgs() << " DestructorAnalysis::mayStoreToMemoryOnDestruction is"
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<< (IsSafe ? " false: " : " true: "));
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DEBUG(T.getSwiftRValueType()->print(llvm::errs()));
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return !IsSafe;
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}
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bool DestructorAnalysis::isSafeType(Type Ty) {
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CanType Cannonical = Ty.getCanonicalTypeOrNull();
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if (Cannonical.isNull())
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return false;
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// Trivial value types.
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if (Cannonical->getKind() == TypeKind::BuiltinInteger)
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return true;
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if (Cannonical->getKind() == TypeKind::BuiltinFloat)
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return true;
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// A struct is safe if
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// * either it implements the _DestructorSafeContainer protocol and
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// all the type parameters are safe types.
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// * or all stored properties are safe types.
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if (auto *Struct = Cannonical->getStructOrBoundGenericStruct()) {
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if (implementsDestructorSafeContainerProtocol(Struct) &&
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areTypeParametersSafe(Cannonical))
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return true;
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// Check the stored properties.
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for (auto SP : Struct->getStoredProperties())
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if (!isSafeType(SP->getType()))
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return false;
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return true;
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}
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// A tuple type is safe if its elements are safe.
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if (auto Tuple = dyn_cast<TupleType>(Cannonical)) {
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for (auto &Elt : Tuple->getFields())
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if (!isSafeType(Elt.getType()))
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return false;
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return true;
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}
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// TODO: enum types.
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return false;
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}
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bool DestructorAnalysis::implementsDestructorSafeContainerProtocol(
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NominalTypeDecl *NomDecl) {
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ProtocolDecl *DestructorSafeContainer =
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getASTContext().getProtocol(KnownProtocolKind::_DestructorSafeContainer);
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for (auto Proto : NomDecl->getProtocols())
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if (Proto == DestructorSafeContainer)
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return true;
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return false;
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}
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bool DestructorAnalysis::areTypeParametersSafe(CanType Ty) {
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auto BGT = dyn_cast<BoundGenericType>(Ty);
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if (!BGT)
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return false;
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// Make sure all type parameters are safe.
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for (auto TP : BGT->getGenericArgs()) {
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if (!isSafeType(TP))
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return false;
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}
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return true;
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}
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ASTContext &DestructorAnalysis::getASTContext() {
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return Mod->getASTContext();
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}
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SILAnalysis *swift::createDestructorAnalysis(SILModule *M) {
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return new DestructorAnalysis(M);
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}
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