DebugTypeInfo: Prefer the size of the Storage type derived from the TypeInfo.

Previously type sizes would be inconsistently sourced from either the LLVM type
or the FixedTypeInfo, depending on the call site. This was problematic because
TypeInfo operates with a resolution of whole bytes, which means that types such
as i1 would get a reported as having a size of 8. This patch now asserts that
all occurrences of the same type have the same size as the first, cached
occurence.

To avoid triggering the cached type verification assertion, this patch avoids
caching of storage-sized containers. It also removes the unique identifier from
forward declarations, which could lead to type confusion during LTO.

rdar://102367872

Author: adrian-prantl

lib/IRGen/DebugTypeInfo.cpp

@@ -47,10 +47,13 @@ static bool hasDefaultAlignment(swift::Type Ty) {
 }
 
 DebugTypeInfo DebugTypeInfo::getFromTypeInfo(swift::Type Ty, const TypeInfo &TI,
+                                             IRGenModule &IGM,
                                              bool IsFragmentTypeInfo) {
   Optional<Size::int_type> SizeInBits;
   llvm::Type *StorageType = TI.getStorageType();
-  if (TI.isFixedSize()) {
+  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;
@@ -63,6 +66,7 @@ DebugTypeInfo DebugTypeInfo::getFromTypeInfo(swift::Type Ty, const TypeInfo &TI,
 
 DebugTypeInfo DebugTypeInfo::getLocalVariable(VarDecl *Decl, swift::Type Ty,
                                               const TypeInfo &Info,
+                                              IRGenModule &IGM,
                                               bool IsFragmentTypeInfo) {
 
   auto DeclType = Decl->getInterfaceType();
@@ -77,7 +81,7 @@ DebugTypeInfo DebugTypeInfo::getLocalVariable(VarDecl *Decl, swift::Type Ty,
   // the type hasn't been mucked with by an optimization pass.
   auto *Type = Sugared->isEqual(RealType) ? DeclType.getPointer()
                                           : RealType.getPointer();
-  return getFromTypeInfo(Type, Info, IsFragmentTypeInfo);
+  return getFromTypeInfo(Type, Info, IGM, IsFragmentTypeInfo);
 }
 
 DebugTypeInfo DebugTypeInfo::getGlobalMetadata(swift::Type Ty,
@@ -120,7 +124,7 @@ DebugTypeInfo DebugTypeInfo::getGlobal(SILGlobalVariable *GV,
       Type = DeclType.getPointer();
   }
   auto &TI = IGM.getTypeInfoForUnlowered(Type);
-  DebugTypeInfo DbgTy = getFromTypeInfo(Type, TI, false);
+  DebugTypeInfo DbgTy = getFromTypeInfo(Type, TI, IGM, false);
   assert(FragmentStorageType && "FragmentStorageType is a nullptr");
   assert(!DbgTy.isContextArchetype() &&
          "type of global variable cannot be an archetype");
@@ -163,7 +167,7 @@ DebugTypeInfo DebugTypeInfo::getObjCClass(ClassDecl *theClass,
 DebugTypeInfo DebugTypeInfo::getErrorResult(swift::Type Ty,
                                             IRGenModule &IGM) {
   auto &TI = IGM.getTypeInfoForUnlowered(Ty);
-  DebugTypeInfo DbgTy = getFromTypeInfo(Ty, TI, false);
+  DebugTypeInfo DbgTy = getFromTypeInfo(Ty, TI, IGM, false);
   return DbgTy;
 }
 
@@ -195,7 +199,8 @@ LLVM_DUMP_METHOD void DebugTypeInfo::dump() const {
   if (SizeInBits)
     llvm::errs() << "SizeInBits " << *SizeInBits << " ";
   llvm::errs() << "Alignment " << Align.getValue() << "] ";
-  getType()->dump(llvm::errs());
+  if (auto *Type = getType())
+    Type->dump(llvm::errs());
 
   if (FragmentStorageType) {
     llvm::errs() << "FragmentStorageType=";

lib/IRGen/DebugTypeInfo.h

@@ -61,7 +61,7 @@ class DebugTypeInfo {
 
   /// Create type for a local variable.
   static DebugTypeInfo getLocalVariable(VarDecl *Decl, swift::Type Ty,
-                                        const TypeInfo &Info,
+                                        const TypeInfo &Info, IRGenModule &IGM,
                                         bool IsFragmentTypeInfo);
   /// Create type for global type metadata.
   static DebugTypeInfo getGlobalMetadata(swift::Type Ty, llvm::Type *StorageTy,
@@ -75,6 +75,7 @@ class DebugTypeInfo {
 
   /// Create a standalone type from a TypeInfo object.
   static DebugTypeInfo getFromTypeInfo(swift::Type Ty, const TypeInfo &Info,
+                                       IRGenModule &IGM,
                                        bool IsFragmentTypeInfo);
   /// Global variables.
   static DebugTypeInfo getGlobal(SILGlobalVariable *GV,
@@ -111,7 +112,6 @@ class DebugTypeInfo {
     return SizeIsFragmentSize ? llvm::None : SizeInBits;
   }
   Optional<Size::int_type> getRawSizeInBits() const { return SizeInBits; }
-  void setSizeInBits(Size::int_type NewSize) { SizeInBits = NewSize; }
   Alignment getAlignment() const { return Align; }
   bool isNull() const { return Type == nullptr; }
   bool isForwardDecl() const { return FragmentStorageType == nullptr; }
@@ -139,9 +139,9 @@ class CompletedDebugTypeInfo : public DebugTypeInfo {
   }
 
   static Optional<CompletedDebugTypeInfo>
-  getFromTypeInfo(swift::Type Ty, const TypeInfo &Info) {
+  getFromTypeInfo(swift::Type Ty, const TypeInfo &Info, IRGenModule &IGM) {
     return CompletedDebugTypeInfo::get(
-        DebugTypeInfo::getFromTypeInfo(Ty, Info, /*IsFragment*/ false));
+        DebugTypeInfo::getFromTypeInfo(Ty, Info, IGM, /*IsFragment*/ false));
   }
 
   Size::int_type getSizeInBits() const { return *SizeInBits; }