Revert "SILCombine: Constant-fold MemoryLayout<T>.offset(of: \.literalKeyPath)"

This reverts commit d7d829c.

The test stdlib/KeyPath.swift is failing on linux.

rdar://problem/64997950

Author: eeckstein

lib/SILOptimizer/SILCombiner/SILCombiner.h

@@ -246,11 +246,8 @@ class SILCombiner :
   bool tryOptimizeKeypath(ApplyInst *AI);
   bool tryOptimizeInoutKeypath(BeginApplyInst *AI);
   bool tryOptimizeKeypathApplication(ApplyInst *AI, SILFunction *callee);
-  bool tryOptimizeKeypathOffsetOf(ApplyInst *AI, FuncDecl *calleeFn,
-                                  KeyPathInst *kp);
-  bool tryOptimizeKeypathKVCString(ApplyInst *AI, FuncDecl *calleeFn,
-                                  KeyPathInst *kp);
-
+  bool tryOptimizeKeypathKVCString(ApplyInst *AI, SILDeclRef callee);
+      
   // Optimize concatenation of string literals.
   // Constant-fold concatenation of string literals known at compile-time.
   SILInstruction *optimizeConcatenationOfStringLiterals(ApplyInst *AI);

lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp

@@ -271,122 +271,6 @@ bool SILCombiner::tryOptimizeKeypathApplication(ApplyInst *AI,
   return true;
 }
 
-/// Replaces a call of the getter of AnyKeyPath._storedInlineOffset with a
-/// "constant" offset, in case of a keypath literal.
-///
-/// "Constant" offset means a series of struct_element_addr and
-/// tuple_element_addr instructions with a 0-pointer as base address.
-/// These instructions can then be lowered to "real" constants in IRGen for
-/// concrete types, or to metatype offset lookups for generic or resilient types.
-///
-/// Replaces:
-///   %kp = keypath ...
-///   %offset = apply %_storedInlineOffset_method(%kp)
-/// with:
-///   %zero = integer_literal $Builtin.Word, 0
-///   %null_ptr = unchecked_trivial_bit_cast %zero to $Builtin.RawPointer
-///   %null_addr = pointer_to_address %null_ptr
-///   %projected_addr = struct_element_addr %null_addr
-///    ... // other address projections
-///   %offset_ptr = address_to_pointer %projected_addr
-///   %offset_builtin_int = unchecked_trivial_bit_cast %offset_ptr
-///   %offset_int = struct $Int (%offset_builtin_int)
-///   %offset = enum $Optional<Int>, #Optional.some!enumelt, %offset_int
-bool SILCombiner::tryOptimizeKeypathOffsetOf(ApplyInst *AI,
-                                             FuncDecl *calleeFn,
-                                             KeyPathInst *kp) {
-  auto *accessor = dyn_cast<AccessorDecl>(calleeFn);
-  if (!accessor || !accessor->isGetter())
-    return false;
-
-  AbstractStorageDecl *storage = accessor->getStorage();
-  DeclName name = storage->getName();
-  if (!name.isSimpleName() ||
-      (name.getBaseIdentifier().str() != "_storedInlineOffset"))
-    return false;
-
-  KeyPathPattern *pattern = kp->getPattern();
-  SubstitutionMap patternSubs = kp->getSubstitutions();
-  CanType rootTy = pattern->getRootType().subst(patternSubs)->getCanonicalType();
-  CanType parentTy = rootTy;
-  
-  // First check if _storedInlineOffset would return an offset or nil. Basically
-  // only stored struct and tuple elements produce an offset. Everything else
-  // (e.g. computed properties, class properties) result in nil.
-  bool hasOffset = true;
-  for (const KeyPathPatternComponent &component : pattern->getComponents()) {
-    switch (component.getKind()) {
-    case KeyPathPatternComponent::Kind::StoredProperty: {
-      if (!parentTy.getStructOrBoundGenericStruct())
-        hasOffset = false;
-      break;
-    }
-    case KeyPathPatternComponent::Kind::TupleElement:
-      break;
-    case KeyPathPatternComponent::Kind::GettableProperty:
-    case KeyPathPatternComponent::Kind::SettableProperty:
-      // We cannot predict the offset of fields in resilient types, because it's
-      // unknown if a resilient field is a computed or stored property.
-      if (component.getExternalDecl())
-        return false;
-      hasOffset = false;
-      break;
-    case KeyPathPatternComponent::Kind::OptionalChain:
-    case KeyPathPatternComponent::Kind::OptionalForce:
-    case KeyPathPatternComponent::Kind::OptionalWrap:
-      hasOffset = false;
-      break;
-    }
-    parentTy = component.getComponentType();
-  }
-
-  SILLocation loc = AI->getLoc();
-  SILValue result;
-
-  if (hasOffset) {
-    SILType rootAddrTy = SILType::getPrimitiveAddressType(rootTy);
-    SILValue rootAddr = Builder.createBaseAddrForOffset(loc, rootAddrTy);
-
-    auto projector = KeyPathProjector::create(kp, rootAddr, loc, Builder);
-    if (!projector)
-      return false;
-
-    // Create the address projections of the keypath.
-    SILType ptrType = SILType::getRawPointerType(Builder.getASTContext());
-    SILValue offsetPtr;
-    projector->project(KeyPathProjector::AccessType::Get, [&](SILValue addr) {
-      offsetPtr = Builder.createAddressToPointer(loc, addr, ptrType);
-    });
-
-    // The result of the _storedInlineOffset call should be Optional<Int>. If
-    // not, something is wrong with the stdlib. Anyway, if it's not like we
-    // expect, bail.
-    SILType intType = AI->getType().getOptionalObjectType();
-    if (!intType)
-      return false;
-    StructDecl *intDecl = intType.getStructOrBoundGenericStruct();
-    if (!intDecl || intDecl->getStoredProperties().size() != 1)
-      return false;
-    VarDecl *member = intDecl->getStoredProperties()[0];
-    CanType builtinIntTy = member->getType()->getCanonicalType();
-    if (!isa<BuiltinIntegerType>(builtinIntTy))
-      return false;
-
-    // Convert the projected address back to an optional integer.
-    SILValue offset = Builder.createUncheckedBitCast(loc, offsetPtr,
-                                SILType::getPrimitiveObjectType(builtinIntTy));
-    SILValue offsetInt = Builder.createStruct(loc, intType, { offset });
-    result = Builder.createOptionalSome(loc, offsetInt, AI->getType());
-  } else {
-    // The keypath has no offset.
-    result = Builder.createOptionalNone(loc, AI->getType());
-  }
-  AI->replaceAllUsesWith(result);
-  eraseInstFromFunction(*AI);
-  ++NumOptimizedKeypaths;
-  return true;
-}
-
 /// Try to optimize a keypath KVC string access on a literal key path.
 ///
 /// Replace:
@@ -395,8 +279,17 @@ bool SILCombiner::tryOptimizeKeypathOffsetOf(ApplyInst *AI,
 /// With:
 ///   %string = string_literal "blah"
 bool SILCombiner::tryOptimizeKeypathKVCString(ApplyInst *AI,
-                                              FuncDecl *calleeFn,
-                                              KeyPathInst *kp) {
+                                              SILDeclRef callee) {
+  if (AI->getNumArguments() != 1) {
+    return false;
+  }
+  if (!callee.hasDecl()) {
+    return false;
+  }
+  auto calleeFn = dyn_cast<FuncDecl>(callee.getDecl());
+  if (!calleeFn)
+    return false;
+  
   if (!calleeFn->getAttrs()
         .hasSemanticsAttr(semantics::KEYPATH_KVC_KEY_PATH_STRING))
     return false;
@@ -407,6 +300,11 @@ bool SILCombiner::tryOptimizeKeypathKVCString(ApplyInst *AI,
   if (!objTy || objTy.getStructOrBoundGenericStruct() != C.getStringDecl())
     return false;
 
+  KeyPathInst *kp
+    = KeyPathProjector::getLiteralKeyPath(AI->getArgument(0));
+  if (!kp || !kp->hasPattern())
+    return false;
+  
   auto objcString = kp->getPattern()->getObjCString();
 
   SILValue literalValue;
@@ -459,33 +357,10 @@ bool SILCombiner::tryOptimizeKeypath(ApplyInst *AI) {
     return tryOptimizeKeypathApplication(AI, callee);
   }
 
-  // Try optimize keypath method calls.
-  auto *methodInst = dyn_cast<ClassMethodInst>(AI->getCallee());
-  if (!methodInst)
-    return false;
-  
-  if (AI->getNumArguments() != 1) {
-    return false;
-  }
-
-  SILDeclRef callee = methodInst->getMember();
-  if (!callee.hasDecl()) {
-    return false;
+  if (auto method = dyn_cast<ClassMethodInst>(AI->getCallee())) {
+    return tryOptimizeKeypathKVCString(AI, method->getMember());
   }
-  auto *calleeFn = dyn_cast<FuncDecl>(callee.getDecl());
-  if (!calleeFn)
-    return false;
-
-  KeyPathInst *kp = KeyPathProjector::getLiteralKeyPath(AI->getArgument(0));
-  if (!kp || !kp->hasPattern())
-    return false;
 
-  if (tryOptimizeKeypathOffsetOf(AI, calleeFn, kp))
-    return true;
-
-  if (tryOptimizeKeypathKVCString(AI, calleeFn, kp))
-    return true;
-
   return false;
 }