Emit pointer-sized structs only when -gdwarf-types is specified.

rdar://problem/25498103

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -1212,11 +1212,18 @@ uint64_t IRGenDebugInfo::getSizeOfBasicType(DebugTypeInfo DbgTy) {
 llvm::DIType *IRGenDebugInfo::createPointerSizedStruct(
     llvm::DIScope *Scope, StringRef Name, llvm::DIFile *File, unsigned Line,
     unsigned Flags, StringRef MangledName) {
-  auto FwdDecl = DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
-                                            Name, Scope, File, Line,
-                                            llvm::dwarf::DW_LANG_Swift, 0, 0);
-  return createPointerSizedStruct(Scope, Name, FwdDecl, File, Line, Flags,
-                                  MangledName);
+  if (Opts.DebugInfoKind > IRGenDebugInfoKind::ASTTypes) {
+    auto FwdDecl = DBuilder.createForwardDecl(
+        llvm::dwarf::DW_TAG_structure_type, Name, Scope, File, Line,
+        llvm::dwarf::DW_LANG_Swift, 0, 0);
+    return createPointerSizedStruct(Scope, Name, FwdDecl, File, Line, Flags,
+                                    MangledName);
+  } else {
+    unsigned SizeInBits = CI.getTargetInfo().getPointerWidth(0);
+    unsigned AlignInBits = CI.getTargetInfo().getPointerAlign(0);
+    return createOpaqueStruct(Scope, Name, File, Line, SizeInBits, AlignInBits,
+                              Flags, MangledName);
+  }
 }
 
 llvm::DIType *IRGenDebugInfo::createPointerSizedStruct(
@@ -1557,10 +1564,14 @@ llvm::DIType *IRGenDebugInfo::createType(DebugTypeInfo DbgTy,
     // DW_TAG_reference_type types, but LLDB can deal better with pointer-sized
     // struct that has the appropriate mangled name.
     auto ObjectTy = BaseTy->castTo<InOutType>()->getObjectType();
-    auto DT = getOrCreateDesugaredType(ObjectTy, DbgTy);
-    return createPointerSizedStruct(Scope, MangledName, DT, File, 0, Flags,
-                                    BaseTy->isUnspecializedGeneric()
-                                    ? StringRef() : MangledName);
+    if (Opts.DebugInfoKind > IRGenDebugInfoKind::ASTTypes) {
+      auto DT = getOrCreateDesugaredType(ObjectTy, DbgTy);
+      return createPointerSizedStruct(
+          Scope, MangledName, DT, File, 0, Flags,
+          BaseTy->isUnspecializedGeneric() ? StringRef() : MangledName);
+    } else
+      return createOpaqueStruct(Scope, MangledName, File, 0, SizeInBits,
+                                AlignInBits, Flags, MangledName);
   }
 
   case TypeKind::Archetype: {

test/DebugInfo/enum.swift

@@ -70,7 +70,9 @@ enum Rose<A> {
 func foo<T>(_ x : Rose<T>) -> Rose<T> { return x }
 
 // CHECK: !DICompositeType({{.*}}name: "Tuple", {{.*}}elements: ![[ELTS:[0-9]+]],
-// CHECK-SAME:             {{.*}}identifier: "_TtGO4enum5Tuplex_")
+// CHECK-SAME:             {{.*}}identifier: "_TtGO4enum5TupleQq_FS_3barurFGS0_x_GS0_x__")
+// DWARF: !DICompositeType({{.*}}name: "Tuple", {{.*}}elements: ![[ELTS:[0-9]+]],
+// DWARF-SAME:             {{.*}}identifier: "_TtGO4enum5Tuplex_")
 public enum Tuple<P> {
   // DWARF: !DICompositeType({{.*}}name: "Tuple",{{.*}}identifier: "_TtGO4enum5TupleQq_S0__")
 	case C(P, () -> Tuple)

test/DebugInfo/protocolarg.swift

@@ -1,6 +1,7 @@
 // RUN: %target-swift-frontend %s -emit-ir -g -o - | FileCheck %s
 
 func markUsed<T>(_ t: T) {}
+func use<T>(_ t: inout T) {}
 
 public protocol IGiveOutInts {
   func callMe() -> Int64
@@ -13,15 +14,16 @@ public protocol IGiveOutInts {
 // CHECK-SAME:              metadata ![[ARG:.*]], metadata ![[DEREF:.*]])
 
 // CHECK: ![[EMPTY]] = !DIExpression()
-// FIXME: Should be DW_TAG_interface_type
-// CHECK: ![[PT:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "IGiveOutInts"
 
 public func printSomeNumbers(_ gen: IGiveOutInts) {
   var gen = gen
   // CHECK: ![[VAR]] = !DILocalVariable(name: "gen", {{.*}} line: [[@LINE-1]]
+  // FIXME: Should be DW_TAG_interface_type
+  // CHECK: ![[PT:.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "IGiveOutInts"
   // CHECK: ![[ARG]] = !DILocalVariable(name: "gen", arg: 1,
-  // CHECK-SAME:                        line: [[@LINE-4]], type: ![[PT]]
+  // CHECK-SAME:                        line: [[@LINE-6]], type: ![[PT]]
   // CHECK: ![[DEREF]] = !DIExpression(DW_OP_deref)
   markUsed(gen.callMe())
+  use(&gen)
 }