Debug Info: Support generic function specialization by substituting

the archetype with the specialized type.

rdar://problem/21949734

Author: adrian-prantl

lib/IRGen/DebugTypeInfo.h

@@ -76,6 +76,19 @@ namespace swift {
         Type = Type->getLValueOrInOutObjectType().getPointer();
       }
 
+      // Determine whether this type is an Archetype itself.
+      bool isArchetype() const {
+        return Type->getLValueOrInOutObjectType()->getKind() ==
+               TypeKind::Archetype;
+      }
+
+      /// LValues, inout args, and Archetypes are implicitly indirect by
+      /// virtue of their DWARF type.
+      bool isImplicitlyIndirect() const {
+        return Type->isLValueType() || isArchetype() ||
+               (Type->getKind() == TypeKind::InOut);
+      }
+      
       bool isNull() const { return Type == nullptr; }
       bool operator==(DebugTypeInfo T) const;
       bool operator!=(DebugTypeInfo T) const;

lib/IRGen/IRGenDebugInfo.cpp

@@ -961,24 +961,6 @@ getStorageSize(const llvm::DataLayout &DL, ArrayRef<llvm::Value *> Storage) {
   return Size(size);
 }
 
-/// LValues, inout args, and Archetypes are implicitly indirect by
-/// virtue of their DWARF type.
-static bool isImplicitlyIndirect(TypeBase *Ty) {
-  switch (Ty->getKind()) {
-  case TypeKind::Paren:
-    return isImplicitlyIndirect(
-        cast<ParenType>(Ty)->getUnderlyingType().getPointer());
-  case TypeKind::NameAlias:
-    return isImplicitlyIndirect(
-        cast<NameAliasType>(Ty)->getSinglyDesugaredType());
-  case TypeKind::InOut:
-  case TypeKind::Archetype:
-    return true;
-  default:
-    return false;
-  }
-}
-
 void IRGenDebugInfo::emitVariableDeclaration(
     IRBuilder &Builder, ArrayRef<llvm::Value *> Storage, DebugTypeInfo DbgTy,
     const SILDebugScope *DS, StringRef Name, unsigned ArgNo,
@@ -1018,9 +1000,6 @@ void IRGenDebugInfo::emitVariableDeclaration(
   if (Artificial || DITy->isArtificial() || DITy == InternalType)
     Flags |= llvm::DINode::FlagArtificial;
 
-  if (isImplicitlyIndirect(DbgTy.getType()))
-    Indirection = DirectValue;
-
   // Create the descriptor for the variable.
   llvm::DILocalVariable *Var = nullptr;
 

lib/IRGen/IRGenSIL.cpp

@@ -3012,11 +3012,18 @@ void IRGenSILFunction::visitDebugValueAddrInst(DebugValueAddrInst *i) {
 
   StringRef Name = getVarName(i);
   auto Addr = getLoweredAddress(SILVal).getAddress();
-  DebugTypeInfo DbgTy(Decl, Decl->getType(), getTypeInfo(SILVal.getType()));
-  // Put the value into a stack slot at -Onone and emit a debug intrinsic.
+  DebugTypeInfo DbgTy(Decl, SILVal.getType().getSwiftType(),
+                      getTypeInfo(SILVal.getType()));
+  // Unwrap implicitly indirect types and types that are passed by
+  // reference only at the SIL level and below.
+  if (DbgTy.isArchetype() || i->getVarInfo().Constant)
+    DbgTy.unwrapLValueOrInOutType();
+  // Put the value's address into a stack slot at -Onone and emit a debug
+  // intrinsic.
   emitDebugVariableDeclaration(
-      emitShadowCopy(Addr, i->getDebugScope(), Name), DbgTy,
-      i->getDebugScope(), Name, i->getVarInfo().ArgNo, IndirectValue);
+      emitShadowCopy(Addr, i->getDebugScope(), Name), DbgTy, i->getDebugScope(),
+      Name, i->getVarInfo().ArgNo,
+      DbgTy.isImplicitlyIndirect() ? DirectValue : IndirectValue);
 }
 
 void IRGenSILFunction::visitLoadWeakInst(swift::LoadWeakInst *i) {
@@ -3427,10 +3434,11 @@ void IRGenSILFunction::visitAllocBoxInst(swift::AllocBoxInst *i) {
     if (Name == IGM.Context.Id_self.str())
       return;
 
+    DebugTypeInfo DbgTy(Decl, i->getElementType().getSwiftType(), type);
     IGM.DebugInfo->emitVariableDeclaration(
         Builder, emitShadowCopy(addr.getAddress(), i->getDebugScope(), Name),
-        DebugTypeInfo(Decl, i->getElementType().getSwiftType(), type),
-        i->getDebugScope(), Name, 0, IndirectValue);
+        DbgTy, i->getDebugScope(), Name, 0,
+        DbgTy.isImplicitlyIndirect() ? DirectValue : IndirectValue);
   }
 }
 

test/DebugInfo/byref-capture.swift

@@ -7,10 +7,11 @@ func makeIncrementor(inc : Int64) -> () -> Int64
   func inner() -> Int64 {
     // CHECK: call void @llvm.dbg.declare(metadata %Vs5Int64**
     // CHECK-SAME:                        metadata ![[SUM_CAPTURE:[0-9]+]],
-    // CHECK-SAME:                        metadata ![[DEREF:[0-9]+]])
-    // CHECK: ![[DEREF]] = !DIExpression(DW_OP_deref)
-    // CHECK: ![[SUM_CAPTURE]] = !DILocalVariable(name: "sum",
-    // CHECK-SAME:                                line: [[@LINE-8]]
+    // CHECK-SAME:                        metadata ![[EMPTY:.*]])
+    // CHECK: ![[EMPTY]] = !DIExpression()
+    // CHECK: ![[SUM_CAPTURE]] = !DILocalVariable(name: "sum", arg: 1,
+    // CHECK-SAME:     line: [[@LINE-8]], type: !"_TtRVs5Int64"
+    //                                               ^ inout type.
     sum += inc
     return sum
   }

test/DebugInfo/specialization.swift

@@ -0,0 +1,18 @@
+// RUN: %target-swift-frontend -O %s -disable-llvm-optzns -emit-sil -g -o - | FileCheck %s
+
+// CHECK: sil shared [noinline] @_TTSg5SiSis21IntegerArithmeticTypes__
+// CHECK-SAME: _TF14specialization3sumuRxs21IntegerArithmeticTyperFTxx_x
+// CHECK-SAME: $@convention(thin) (@out Int, @in Int, @in Int) -> () {
+// CHECK: bb0(%0 : $*Int, %1 : $*Int, %2 : $*Int):
+// CHECK:  debug_value_addr %1 : $*Int, let, name "i", argno 1
+// CHECK:  debug_value_addr %2 : $*Int, let, name "j", argno 2
+  
+@inline(never)
+public func sum<T : IntegerArithmeticType>(i : T, _ j : T) -> T {
+  let result = i + j
+  return result
+}
+
+public func inc(inout i : Int) {
+  i = sum(i, 1)
+}