Merge pull request #16515 from shajrawi/resilient_in_struct

[IRGen] Fix offset calculation when having a struct with a resilient type as its first field

Author: Joe Shajrawi

lib/IRGen/GenHeap.cpp

@@ -81,6 +81,34 @@ HeapLayout::HeapLayout(IRGenModule &IGM, LayoutStrategy strategy,
 #endif
 }
 
+static llvm::Value *calcInitOffset(swift::irgen::IRGenFunction &IGF,
+                                   unsigned int i,
+                                   const swift::irgen::HeapLayout &layout) {
+  llvm::Value *offset = nullptr;
+  if (i == 0) {
+    auto startoffset = layout.getSize();
+    offset = llvm::ConstantInt::get(IGF.IGM.SizeTy, startoffset.getValue());
+    return offset;
+  }
+  auto &prevElt = layout.getElement(i - 1);
+  auto prevType = layout.getElementTypes()[i - 1];
+  // Start calculating offsets from the last fixed-offset field.
+  Size lastFixedOffset = layout.getElement(i - 1).getByteOffset();
+  if (auto *fixedType = dyn_cast<FixedTypeInfo>(&prevElt.getTypeForLayout())) {
+    // If the last fixed-offset field is also fixed-size, we can
+    // statically compute the end of the fixed-offset fields.
+    auto fixedEnd = lastFixedOffset + fixedType->getFixedSize();
+    offset = llvm::ConstantInt::get(IGF.IGM.SizeTy, fixedEnd.getValue());
+  } else {
+    // Otherwise, we need to add the dynamic size to the fixed start
+    // offset.
+    offset = llvm::ConstantInt::get(IGF.IGM.SizeTy, lastFixedOffset.getValue());
+    offset = IGF.Builder.CreateAdd(
+        offset, prevElt.getTypeForLayout().getSize(IGF, prevType));
+  }
+  return offset;
+}
+
 HeapNonFixedOffsets::HeapNonFixedOffsets(IRGenFunction &IGF,
                                          const HeapLayout &layout) {
   if (!layout.isFixedLayout()) {
@@ -107,34 +135,8 @@ HeapNonFixedOffsets::HeapNonFixedOffsets(IRGenFunction &IGF,
       case ElementLayout::Kind::NonFixed:
         // Start calculating non-fixed offsets from the end of the first fixed
         // field.
-        if (i == 0) {
-          totalAlign = elt.getTypeForLayout().getAlignmentMask(IGF, eltTy);
-          offset = totalAlign;
-          Offsets.push_back(totalAlign);
-          break;
-        }
-
-        assert(i > 0 && "shouldn't begin with a non-fixed field");
-        auto &prevElt = layout.getElement(i-1);
-        auto prevType = layout.getElementTypes()[i-1];
-        // Start calculating offsets from the last fixed-offset field.
         if (!offset) {
-          Size lastFixedOffset = layout.getElement(i-1).getByteOffset();
-          if (auto *fixedType = dyn_cast<FixedTypeInfo>(&prevElt.getTypeForLayout())) {
-            // If the last fixed-offset field is also fixed-size, we can
-            // statically compute the end of the fixed-offset fields.
-            auto fixedEnd = lastFixedOffset + fixedType->getFixedSize();
-            offset
-              = llvm::ConstantInt::get(IGF.IGM.SizeTy, fixedEnd.getValue());
-          } else {
-            // Otherwise, we need to add the dynamic size to the fixed start
-            // offset.
-            offset
-              = llvm::ConstantInt::get(IGF.IGM.SizeTy,
-                                       lastFixedOffset.getValue());
-            offset = IGF.Builder.CreateAdd(offset,
-                                     prevElt.getTypeForLayout().getSize(IGF, prevType));
-          }
+          offset = calcInitOffset(IGF, i, layout);
         }
 
         // Round up to alignment to get the offset.

test/IRGen/struct_with_resilient_type.swift

@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-module -enable-resilience -emit-module-path=%t/resilient_struct.swiftmodule -module-name=resilient_struct %S/../Inputs/resilient_struct.swift
+// RUN: %target-swift-frontend -I %t -emit-ir %s | %FileCheck %s
+
+// REQUIRES: CPU=x86_64
+
+import resilient_struct
+
+struct StructWithFunc {
+  func foo(ptr: @escaping () -> Void) {
+  }
+}
+
+struct ProtAndResilStruct {
+  let foundationType: ResilientBool
+  
+  let fooImp: StructWithFunc
+  
+  init(fType: ResilientBool, fooImp: StructWithFunc) {
+    self.foundationType = fType
+    self.fooImp = fooImp
+  }
+  
+  func bar() {
+  }
+  
+  func crash() {
+    fooImp.foo(ptr: bar)
+  }
+// CHECK-LABEL: define{{.*}} @"$S26struct_with_resilient_type18ProtAndResilStructV3baryyFTc"(%T26struct_with_resilient_type18ProtAndResilStructV* noalias nocapture)
+// CHECK:   %flags.alignmentMask = and i64 %flags, 65535
+// CHECK: [[XOR_ALIGN:%.*]] = xor i64 %flags.alignmentMask, -1
+// CHECK: [[INIT_OFFSET:%.*]] = add i64 16, %flags.alignmentMask
+// CHECK: [[T0:%.*]] = and i64 [[INIT_OFFSET]], [[XOR_ALIGN]]
+// CHECK: [[T1:%.*]] = add i64 [[T0]], %size
+// CHECK: [[ALIGN:%.*]] = or i64 7, %flags.alignmentMask
+}
+
+func crashCaller() {
+  let fType = ResilientBool(b: false)
+  let fooImp = StructWithFunc()
+  let badStruct = ProtAndResilStruct(fType: fType, fooImp: fooImp)
+  badStruct.crash()
+}
+
+crashCaller()