SILFunction: add getMemoryBehavior

This retrieves the side effect information from the function effects.

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Function.swift

@@ -305,6 +305,11 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
           }
         }
         return BridgedEffectInfo(argumentIndex: -1, isDerived: false, isEmpty: true, isValid: false)
+      },
+      // getMemBehaviorFn
+      { (f: BridgedFunction, observeRetains: Bool) -> BridgedMemoryBehavior in
+        let e = f.function.getSideEffects()
+        return e.getMemBehavior(observeRetains: observeRetains)
       }
     )
   }
@@ -335,3 +340,17 @@ extension BridgedFunction {
 extension OptionalBridgedFunction {
   public var function: Function? { obj.getAs(Function.self) }
 }
+
+public extension SideEffects.GlobalEffects {
+  func getMemBehavior(observeRetains: Bool) -> BridgedMemoryBehavior {
+    if allocates || ownership.destroy || (ownership.copy && observeRetains) {
+      return MayHaveSideEffectsBehavior
+    }
+    switch (memory.read, memory.write) {
+    case (false, false): return NoneBehavior
+    case (true, false): return MayReadBehavior
+    case (false, true): return MayWriteBehavior
+    case (true, true): return MayReadWriteBehavior
+    }
+  }
+}

include/swift/SIL/SILBridging.h

@@ -244,12 +244,14 @@ typedef BridgedParsingError (*_Nonnull FunctionParseFn)(BridgedFunction,
 typedef SwiftInt (* _Nonnull FunctionCopyEffectsFn)(BridgedFunction,
                                                     BridgedFunction);
 typedef BridgedEffectInfo (* _Nonnull FunctionGetEffectInfoFn)(BridgedFunction, SwiftInt);
+typedef BridgedMemoryBehavior (* _Nonnull FunctionGetMemBehviorFn)(BridgedFunction, bool);
 
 void Function_register(SwiftMetatype metatype,
             FunctionRegisterFn initFn, FunctionRegisterFn destroyFn,
             FunctionWriteFn writeFn, FunctionParseFn parseFn,
             FunctionCopyEffectsFn copyEffectsFn,
-            FunctionGetEffectInfoFn effectInfoFn);
+            FunctionGetEffectInfoFn effectInfoFn,
+            FunctionGetMemBehviorFn memBehaviorFn);
 
 SwiftInt PassContext_continueWithNextSubpassRun(BridgedPassContext passContext,
                                                 OptionalBridgedInstruction inst);

include/swift/SIL/SILFunction.h

@@ -1055,6 +1055,7 @@ class SILFunction
   void copyEffects(SILFunction *from);
   bool hasArgumentEffects() const;
   void visitArgEffects(std::function<void(int, int, bool)> c) const;
+  SILInstruction::MemoryBehavior getMemoryBehavior(bool observeRetains);
 
   Purpose getSpecialPurpose() const { return specialPurpose; }
 

lib/SIL/IR/SILFunction.cpp

@@ -146,6 +146,7 @@ static FunctionWriteFn writeFunction = nullptr;
 static FunctionParseFn parseFunction = nullptr;
 static FunctionCopyEffectsFn copyEffectsFunction = nullptr;
 static FunctionGetEffectInfoFn getEffectInfoFunction = nullptr;
+static FunctionGetMemBehviorFn getMemBehvaiorFunction = nullptr;
 
 SILFunction::SILFunction(
     SILModule &Module, SILLinkage Linkage, StringRef Name,
@@ -932,14 +933,16 @@ void Function_register(SwiftMetatype metatype,
             FunctionRegisterFn initFn, FunctionRegisterFn destroyFn,
             FunctionWriteFn writeFn, FunctionParseFn parseFn,
             FunctionCopyEffectsFn copyEffectsFn,
-            FunctionGetEffectInfoFn effectInfoFn) {
+            FunctionGetEffectInfoFn effectInfoFn,
+            FunctionGetMemBehviorFn memBehaviorFn) {
   functionMetatype = metatype;
   initFunction = initFn;
   destroyFunction = destroyFn;
   writeFunction = writeFn;
   parseFunction = parseFn;
   copyEffectsFunction = copyEffectsFn;
   getEffectInfoFunction = effectInfoFn;
+  getMemBehvaiorFunction = memBehaviorFn;
 }
 
 std::pair<const char *, int>  SILFunction::
@@ -1020,6 +1023,14 @@ visitArgEffects(std::function<void(int, int, bool)> c) const {
   }
 }
 
+SILInstruction::MemoryBehavior SILFunction::getMemoryBehavior(bool observeRetains) {
+  if (!getMemBehvaiorFunction)
+    return SILInstruction::MemoryBehavior::MayHaveSideEffects;
+
+  auto b = getMemBehvaiorFunction({this}, observeRetains);
+  return (SILInstruction::MemoryBehavior)b;
+}
+
 SILFunction *SILFunction::getFunction(SILDeclRef ref, SILModule &M) {
   swift::Lowering::SILGenModule SILGenModule(M, ref.getModuleContext());
   return SILGenModule.getFunction(ref, swift::NotForDefinition);