Merge pull request #84595 from meg-gupta/moreborrowaccessors

Extend borrow accessor support

Author: meg-gupta

include/swift/AST/DeclAttr.def

@@ -902,7 +902,12 @@ DECL_ATTR(specialized, Specialized,
   AllowMultipleAttributes | LongAttribute | UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   172)
 
-LAST_DECL_ATTR(Specialized)
+SIMPLE_DECL_ATTR(_unsafeSelfDependentResult, UnsafeSelfDependentResult,
+  OnAccessor,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIBreakingToAdd | APIBreakingToRemove | EquivalentInABIAttr,
+  173)
+
+LAST_DECL_ATTR(UnsafeSelfDependentResult)
 
 #undef DECL_ATTR_ALIAS
 #undef CONTEXTUAL_DECL_ATTR_ALIAS

include/swift/AST/DiagnosticsSema.def

@@ -8946,5 +8946,8 @@ GROUPED_WARNING(perf_hint_closure_returns_array,ReturnTypeImplicitCopy,DefaultIg
                 "Performance: closure returns a%select{ dictionary|n array}0, leading to implicit copies. "
                 "Consider using an 'inout' parameter instead.", (bool))
 
+ERROR(unsafe_self_dependent_result_attr_on_invalid_decl,none,
+      "invalid use of @_unsafeSelfDependentResult", ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

include/swift/AST/Types.h

@@ -5401,6 +5401,13 @@ class SILFunctionType final
     return hasErrorResult() && getErrorResult().isFormalIndirect();
   }
 
+  bool hasGuaranteedResult() const {
+    if (getNumResults() != 1) {
+      return false;
+    }
+    return getResults()[0].isGuaranteedResult();
+  }
+
   bool hasGuaranteedAddressResult() const {
     if (getNumResults() != 1) {
       return false;

include/swift/SIL/InstructionUtils.h

@@ -41,6 +41,8 @@ SILValue stripCastsWithoutMarkDependence(SILValue V);
 /// begin_borrow instructions.
 SILValue lookThroughOwnershipInsts(SILValue v);
 
+SILValue lookThroughMoveOnlyCheckerPattern(SILValue value);
+
 /// Reverse of lookThroughOwnershipInsts.
 ///
 /// Return true if \p visitor returned true for all uses.

include/swift/SIL/MemAccessUtils.h

@@ -1809,9 +1809,11 @@ Result AccessUseDefChainVisitor<Impl, Result>::visit(SILValue sourceAddr) {
       return asImpl().visitUnidentified(sourceAddr);
 
     if (isGuaranteedAddressReturn(sourceAddr)) {
-      return asImpl().visitAccessProjection(
-          cast<ApplyInst>(sourceAddr),
-          &cast<ApplyInst>(sourceAddr)->getSelfArgumentOperand());
+      auto *selfOp = &cast<ApplyInst>(sourceAddr)->getSelfArgumentOperand();
+      if (selfOp->get()->getType().isObject()) {
+        return asImpl().visitUnidentified(sourceAddr);
+      }
+      return asImpl().visitAccessProjection(cast<ApplyInst>(sourceAddr), selfOp);
     }
 
     // Don't currently allow any other calls to return an accessed address.

include/swift/SIL/SILValue.h

@@ -616,6 +616,8 @@ class ValueBase : public SILNode, public SILAllocated<ValueBase> {
 
   bool isBeginApplyToken() const;
 
+  bool isBorrowAccessorResult() const;
+
   /// Unsafely eliminate moveonly from this value's type. Returns true if the
   /// value's underlying type was move only and thus was changed. Returns false
   /// otherwise.

lib/AST/ASTDumper.cpp

@@ -5062,6 +5062,7 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(WeakLinked, weak_linked)
   TRIVIAL_ATTR_PRINTER(Nonexhaustive, nonexhaustive)
   TRIVIAL_ATTR_PRINTER(Concurrent, concurrent)
+  TRIVIAL_ATTR_PRINTER(UnsafeSelfDependentResult, unsafe_self_dependent_result)
 
 #undef TRIVIAL_ATTR_PRINTER
 

lib/ASTGen/Sources/ASTGen/DeclAttrs.swift

@@ -309,7 +309,8 @@ extension ASTGenVisitor {
         .UsableFromInline,
         .Used,
         .WarnUnqualifiedAccess,
-        .WeakLinked:
+        .WeakLinked,
+        .UnsafeSelfDependentResult:
 
         return handle(self.generateSimpleDeclAttr(attribute: node, kind: attrKind!))
 

lib/IRGen/CallEmission.h

@@ -103,6 +103,7 @@ class CallEmission {
   virtual void emitCallToUnmappedExplosion(llvm::CallBase *call,
                                            Explosion &out) = 0;
   void emitYieldsToExplosion(Explosion &out);
+  void emitGuaranteedAddressToExplosion(Explosion &out);
   void setKeyPathAccessorArguments(Explosion &in, bool isOutlined,
                                    Explosion &out);
   virtual FunctionPointer getCalleeFunctionPointer() = 0;

lib/IRGen/GenCall.cpp

@@ -591,6 +591,10 @@ namespace {
     /// function type.
     void expandCoroutineContinuationType();
 
+    /// Initializes the result type for functions with @guaranteed_addr return
+    /// convention.
+    void expandGuaranteedAddressResult();
+
     // Expand the components for the async continuation entrypoint of the
     // function type (the function to be called on returning).
     void expandAsyncReturnType();
@@ -694,6 +698,10 @@ void SignatureExpansion::expandResult(
 
   auto fnConv = getSILFuncConventions();
 
+  if (fnConv.hasGuaranteedAddressResult()) {
+    return expandGuaranteedAddressResult();
+  }
+
   // Disable the use of sret if we have multiple indirect results.
   if (fnConv.getNumIndirectSILResults() > 1)
     CanUseSRet = false;
@@ -911,6 +919,11 @@ void SignatureExpansion::expandCoroutineContinuationParameters() {
   }
 }
 
+void SignatureExpansion::expandGuaranteedAddressResult() {
+  CanUseSRet = false;
+  ResultIRType = IGM.PtrTy;
+}
+
 void SignatureExpansion::addAsyncParameters() {
   // using TaskContinuationFunction =
   //   SWIFT_CC(swift)
@@ -3945,6 +3958,11 @@ void CallEmission::emitYieldsToExplosion(Explosion &out) {
   }
 }
 
+void CallEmission::emitGuaranteedAddressToExplosion(Explosion &out) {
+  auto call = emitCallSite();
+  out.add(call);
+}
+
 /// Emit the result of this call to an explosion.
 void CallEmission::emitToExplosion(Explosion &out, bool isOutlined) {
   assert(state == State::Emitting);
@@ -3960,6 +3978,14 @@ void CallEmission::emitToExplosion(Explosion &out, bool isOutlined) {
 
   SILFunctionConventions fnConv(getCallee().getSubstFunctionType(),
                                 IGF.getSILModule());
+
+  if (fnConv.hasGuaranteedAddressResult()) {
+    assert(LastArgWritten == 0 &&
+           "@guaranteed_addr along with indirect result?");
+    emitGuaranteedAddressToExplosion(out);
+    return;
+  }
+
   SILType substResultType =
       fnConv.getSILResultType(IGF.IGM.getMaximalTypeExpansionContext());
 
@@ -7019,6 +7045,16 @@ void irgen::emitYieldOnceCoroutineResult(IRGenFunction &IGF, Explosion &result,
   }
 }
 
+void irgen::emitGuaranteedAddressResult(IRGenFunction &IGF, Explosion &result,
+                                        SILType funcResultType,
+                                        SILType returnResultType) {
+  assert(funcResultType == returnResultType);
+  assert(funcResultType.isAddress());
+  auto &Builder = IGF.Builder;
+  Builder.CreateRet(result.claimNext());
+  assert(result.empty());
+}
+
 FunctionPointer
 IRGenFunction::getFunctionPointerForResumeIntrinsic(llvm::Value *resume) {
   auto *fnTy = llvm::FunctionType::get(