Emit extra inhabitants in debug info for basic types

To support debugging embedded Swift, we will need to store information
that previously we searched in metadata. Extra inhabitants is one of
those.

Author: augusto2112

lib/IRGen/DebugTypeInfo.cpp

@@ -29,11 +29,13 @@ DebugTypeInfo::DebugTypeInfo(swift::Type Ty, llvm::Type *FragmentStorageTy,
                              llvm::Optional<Size::int_type> SizeInBits,
                              Alignment Align, bool HasDefaultAlignment,
                              bool IsMetadata, bool SizeIsFragmentSize,
-                             bool IsFixedBuffer)
+                             bool IsFixedBuffer,
+                             std::optional<uint32_t> NumExtraInhabitants)
     : Type(Ty.getPointer()), FragmentStorageType(FragmentStorageTy),
-      SizeInBits(SizeInBits), Align(Align),
-      DefaultAlignment(HasDefaultAlignment), IsMetadataType(IsMetadata),
-      SizeIsFragmentSize(SizeIsFragmentSize), IsFixedBuffer(IsFixedBuffer) {
+      SizeInBits(SizeInBits), NumExtraInhabitants(NumExtraInhabitants),
+      Align(Align), DefaultAlignment(HasDefaultAlignment),
+      IsMetadataType(IsMetadata), SizeIsFragmentSize(SizeIsFragmentSize),
+      IsFixedBuffer(IsFixedBuffer) {
   assert(Align.getValue() != 0);
 }
 
@@ -52,17 +54,22 @@ DebugTypeInfo DebugTypeInfo::getFromTypeInfo(swift::Type Ty, const TypeInfo &TI,
                                              bool IsFragmentTypeInfo) {
   llvm::Optional<Size::int_type> SizeInBits;
   llvm::Type *StorageType = TI.getStorageType();
+  std::optional<uint32_t> NumExtraInhabitants;
   if (StorageType->isSized())
     SizeInBits = IGM.DataLayout.getTypeSizeInBits(StorageType);
   else if (TI.isFixedSize()) {
     const FixedTypeInfo &FixTy = *cast<const FixedTypeInfo>(&TI);
     Size::int_type Size = FixTy.getFixedSize().getValue() * 8;
     SizeInBits = Size;
   }
+  if (TI.isFixedSize()) {
+    const FixedTypeInfo &FixTy = *cast<const FixedTypeInfo>(&TI);
+    NumExtraInhabitants = FixTy.getFixedExtraInhabitantCount(IGM);
+  }
   assert(TI.getStorageType() && "StorageType is a nullptr");
   return DebugTypeInfo(Ty.getPointer(), StorageType, SizeInBits,
                        TI.getBestKnownAlignment(), ::hasDefaultAlignment(Ty),
-                       false, IsFragmentTypeInfo);
+                       false, IsFragmentTypeInfo, false, NumExtraInhabitants);
 }
 
 DebugTypeInfo DebugTypeInfo::getLocalVariable(VarDecl *Decl, swift::Type Ty,

lib/IRGen/DebugTypeInfo.h

@@ -45,6 +45,7 @@ class DebugTypeInfo {
   /// the storage type for undefined variables.
   llvm::Type *FragmentStorageType = nullptr;
   llvm::Optional<Size::int_type> SizeInBits;
+  std::optional<uint32_t> NumExtraInhabitants;
   Alignment Align;
   bool DefaultAlignment = true;
   bool IsMetadataType = false;
@@ -57,7 +58,8 @@ class DebugTypeInfo {
                 llvm::Optional<Size::int_type> SizeInBits = {},
                 Alignment AlignInBytes = Alignment(1),
                 bool HasDefaultAlignment = true, bool IsMetadataType = false,
-                bool IsFragmentTypeInfo = false, bool IsFixedBuffer = false);
+                bool IsFragmentTypeInfo = false, bool IsFixedBuffer = false,
+                std::optional<uint32_t> NumExtraInhabitants = {});
 
   /// Create type for a local variable.
   static DebugTypeInfo getLocalVariable(VarDecl *Decl, swift::Type Ty,
@@ -119,6 +121,9 @@ class DebugTypeInfo {
   bool hasDefaultAlignment() const { return DefaultAlignment; }
   bool isSizeFragmentSize() const { return SizeIsFragmentSize; }
   bool isFixedBuffer() const { return IsFixedBuffer; }
+  std::optional<uint32_t> getNumExtraInhabitants() const {
+    return NumExtraInhabitants;
+  }
 
   bool operator==(DebugTypeInfo T) const;
   bool operator!=(DebugTypeInfo T) const;

lib/IRGen/IRGenDebugInfo.cpp

@@ -1363,6 +1363,7 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
                                ? 0
                                : DbgTy.getAlignment().getValue() * SizeOfByte;
     unsigned Encoding = 0;
+    uint32_t NumExtraInhabitants = 0;
     llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
 
     TypeBase *BaseTy = DbgTy.getType();
@@ -1386,13 +1387,17 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       Encoding = llvm::dwarf::DW_ATE_unsigned;
       if (auto CompletedDbgTy = CompletedDebugTypeInfo::get(DbgTy))
         SizeInBits = getSizeOfBasicType(*CompletedDbgTy);
+      if (auto DbgTyNumExtraInhabitants = DbgTy.getNumExtraInhabitants())
+        NumExtraInhabitants = *DbgTyNumExtraInhabitants;
       break;
     }
 
     case TypeKind::BuiltinIntegerLiteral: {
       Encoding = llvm::dwarf::DW_ATE_unsigned; // ?
       if (auto CompletedDbgTy = CompletedDebugTypeInfo::get(DbgTy))
         SizeInBits = getSizeOfBasicType(*CompletedDbgTy);
+      if (auto DbgTyNumExtraInhabitants = DbgTy.getNumExtraInhabitants())
+        NumExtraInhabitants = *DbgTyNumExtraInhabitants;
       break;
     }
 
@@ -1401,6 +1406,8 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       // Assuming that the bitwidth and FloatTy->getFPKind() are identical.
       SizeInBits = FloatTy->getBitWidth();
       Encoding = llvm::dwarf::DW_ATE_float;
+      if (auto DbgTyNumExtraInhabitants = DbgTy.getNumExtraInhabitants())
+        NumExtraInhabitants = *DbgTyNumExtraInhabitants;
       break;
     }
 
@@ -1726,7 +1733,8 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
       DebugTypeInfo AliasedDbgTy(
           AliasedTy, DbgTy.getFragmentStorageType(), DbgTy.getRawSizeInBits(),
           DbgTy.getAlignment(), DbgTy.hasDefaultAlignment(), false,
-          DbgTy.isSizeFragmentSize(), DbgTy.isFixedBuffer());
+          DbgTy.isSizeFragmentSize(), DbgTy.isFixedBuffer(),
+          DbgTy.getNumExtraInhabitants());
       return DBuilder.createTypedef(getOrCreateType(AliasedDbgTy), MangledName,
                                     File, 0, Scope);
     }
@@ -1774,7 +1782,9 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
                  DbgTy.getType()->dump(llvm::dbgs()); llvm::dbgs() << "\n");
       MangledName = "<unknown>";
     }
-    return DBuilder.createBasicType(MangledName, SizeInBits, Encoding);
+    return DBuilder.createBasicType(MangledName, SizeInBits, Encoding,
+                                    llvm::DINode::FlagZero,
+                                    NumExtraInhabitants);
   }
 
   /// Determine if there exists a name mangling for the given type.

test/DebugInfo/bool.swift

@@ -5,7 +5,7 @@
 func markUsed<T>(_ t: T) {}
 
 // Int1 uses 1 bit, but is aligned at 8 bits.
-// CHECK: !DIBasicType(name: "$sBi1_D", size: 1, encoding: DW_ATE_unsigned)
+// CHECK: !DIBasicType(name: "$sBi1_D", size: 1, encoding: DW_ATE_unsigned, num_extra_inhabitants: 254)
 // Bool has a fixed layout with a storage size of 1 byte and 7 "spare" bits.
 // CHECK_G: !DICompositeType(tag: DW_TAG_structure_type, name: "Bool",
 // CHECK_G-SAME:             size: 8