Implement TypeSystemSwiftTypeRef::GetTypeBitAlign() (NFC)

This also fixes a pretty serious bit/byte bug in
SwiftASTContext::GetTypeBitAlign() that go uncovered by the new
validation assertion.

<rdar://problem/68171432>

(cherry picked from commit 593758e)

Author: adrian-prantl

lldb/include/lldb/Target/SwiftLanguageRuntime.h

@@ -260,7 +260,8 @@ class SwiftLanguageRuntime : public LanguageRuntime {
   llvm::Optional<uint64_t> GetByteStride(CompilerType type);
 
   /// Ask Remote mirrors for the alignment of a Swift type.
-  llvm::Optional<size_t> GetBitAlignment(CompilerType type);
+  llvm::Optional<size_t> GetBitAlignment(CompilerType type,
+                                         ExecutionContextScope *exe_scope);
 
   /// Release the RemoteASTContext associated with the given swift::ASTContext.
   /// Note that a RemoteASTContext must be destroyed before its associated

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -6039,20 +6039,22 @@ SwiftASTContext::GetTypeBitAlign(opaque_compiler_type_t type,
     exe_scope->CalculateExecutionContext(exe_ctx);
     auto swift_scratch_ctx_lock = SwiftASTContextLock(&exe_ctx);
     CompilerType bound_type = BindGenericTypeParameters({this, type}, exe_scope);
+    if (bound_type.GetOpaqueQualType() == type)
+      return {};
     // Note thay the bound type may be in a different AST context.
     return bound_type.GetTypeBitAlign(exe_scope);
   }
 
   const swift::irgen::FixedTypeInfo *fixed_type_info =
       GetSwiftFixedTypeInfo(type);
   if (fixed_type_info)
-    return fixed_type_info->getFixedAlignment().getValue();
+    return fixed_type_info->getFixedAlignment().getValue() * 8;
 
   // Ask the dynamic type system.
   if (!exe_scope)
     return {};
   if (auto *runtime = SwiftLanguageRuntime::Get(exe_scope->CalculateProcess()))
-    return runtime->GetBitAlignment({this, type});
+    return runtime->GetBitAlignment({this, type}, exe_scope);
   return {};
 }
 

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp

@@ -1033,6 +1033,30 @@ DWARFASTParser *TypeSystemSwiftTypeRef::GetDWARFParser() {
   return m_swift_ast_context->GetDWARFParser();
 }
 
+TypeSP TypeSystemSwiftTypeRef::LookupTypeInModule(
+    lldb::opaque_compiler_type_t opaque_type) {
+  auto *M = GetModule();
+  if (!M)
+    return {};
+  swift::Demangle::Demangler dem;
+  auto *node = GetDemangledType(dem, AsMangledName(opaque_type));
+  auto module_type = GetNominal(dem, node);
+  if (!module_type)
+    return {};
+  // DW_AT_linkage_name is not part of the accelerator table, so
+  // we need to search by module+name.
+  ConstString module(module_type->first);
+  ConstString type(module_type->second);
+  llvm::SmallVector<CompilerContext, 2> decl_context;
+  decl_context.push_back({CompilerContextKind::Module, module});
+  decl_context.push_back({CompilerContextKind::AnyType, type});
+  llvm::DenseSet<SymbolFile *> searched_symbol_files;
+  TypeMap types;
+  M->FindTypes(decl_context, TypeSystemSwift::GetSupportedLanguagesForTypes(),
+               searched_symbol_files, types);
+  return types.Empty() ? TypeSP() : types.GetTypeAtIndex(0);
+}
+
 // Tests
 
 #ifndef NDEBUG
@@ -1680,27 +1704,8 @@ TypeSystemSwiftTypeRef::GetBitSize(opaque_compiler_type_t type,
     // If there is no process, we can still try to get the static size
     // information out of DWARF. Because it is stored in the Type
     // object we need to look that up by name again.
-    if (auto *M = GetModule()) {
-      swift::Demangle::Demangler dem;
-      auto node = GetDemangledType(dem, AsMangledName(type));
-      if (auto module_type = GetNominal(dem, node)) {
-        // DW_AT_linkage_name is not part of the accelerator table, so
-        // we need to search by module+name.
-        ConstString module(module_type->first);
-        ConstString type(module_type->second);
-        llvm::SmallVector<CompilerContext, 2> decl_context;
-        decl_context.push_back({CompilerContextKind::Module, module});
-        decl_context.push_back({CompilerContextKind::AnyType, type});
-        llvm::DenseSet<SymbolFile *> searched_symbol_files;
-        TypeMap types;
-        M->FindTypes(decl_context,
-                     TypeSystemSwift::GetSupportedLanguagesForTypes(),
-                     searched_symbol_files, types);
-        if (!types.Empty())
-          if (auto type = types.GetTypeAtIndex(0))
-            return type->GetByteSize(nullptr);
-      }
-    }
+    if (TypeSP type_sp = LookupTypeInModule(type))
+      return type_sp->GetByteSize(exe_scope);
     LLDB_LOGF(GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES),
               "Couldn't compute size of type %s without a process.",
               AsMangledName(type));
@@ -1955,7 +1960,41 @@ bool TypeSystemSwiftTypeRef::IsPointerOrReferenceType(
 llvm::Optional<size_t>
 TypeSystemSwiftTypeRef::GetTypeBitAlign(opaque_compiler_type_t type,
                                         ExecutionContextScope *exe_scope) {
-  return m_swift_ast_context->GetTypeBitAlign(ReconstructType(type), exe_scope);
+    auto impl = [&]() -> llvm::Optional<size_t> {
+    // Clang types can be resolved even without a process.
+    if (CompilerType clang_type = GetAsClangTypeOrNull(type)) {
+      // Swift doesn't know pointers: return the size alignment of the
+      // object pointer instead of the underlying object.
+      if (Flags(clang_type.GetTypeInfo()).AllSet(eTypeIsObjC | eTypeIsClass))
+        return GetPointerByteSize() * 8;
+      return clang_type.GetTypeBitAlign(exe_scope);
+    }
+    if (!exe_scope) {
+      LLDB_LOGF(GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES),
+                "Couldn't compute alignment of type %s without an execution "
+                "context.",
+                AsMangledName(type));
+      return {};
+    }
+    if (auto *runtime =
+            SwiftLanguageRuntime::Get(exe_scope->CalculateProcess()))
+      return runtime->GetBitAlignment({this, type}, exe_scope);
+
+    // If there is no process, we can still try to get the static
+    // alignment information out of DWARF. Because it is stored in the
+    // Type object we need to look that up by name again.
+    if (TypeSP type_sp = LookupTypeInModule(type))
+      return type_sp->GetLayoutCompilerType().GetTypeBitAlign(exe_scope);
+    LLDB_LOGF(GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES),
+              "Couldn't compute alignment of type %s without a process.",
+              AsMangledName(type));
+    return {};
+  };
+  if (exe_scope && exe_scope->CalculateProcess())
+    VALIDATE_AND_RETURN(impl, GetTypeBitAlign, type,
+                        (ReconstructType(type), exe_scope));
+  else
+    return impl();
 }
 bool TypeSystemSwiftTypeRef::IsTypedefType(opaque_compiler_type_t type) {
   return m_swift_ast_context->IsTypedefType(ReconstructType(type));

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.h

@@ -277,6 +277,9 @@ class TypeSystemSwiftTypeRef : public TypeSystemSwift {
   /// Cast \p opaque_type as a mangled name.
   const char *AsMangledName(lldb::opaque_compiler_type_t type);
 
+  /// Lookup a type in the debug info.
+  lldb::TypeSP LookupTypeInModule(lldb::opaque_compiler_type_t type);
+
   /// Demangle the mangled name of the canonical type of \p type and
   /// drill into the Global(TypeMangling(Type())).
   ///

lldb/source/Target/SwiftLanguageRuntime.cpp

@@ -270,7 +270,8 @@ class SwiftLanguageRuntimeStub {
     return {};
   }
 
-  llvm::Optional<size_t> GetBitAlignment(CompilerType type) {
+  llvm::Optional<size_t> GetBitAlignment(CompilerType type,
+                                         ExecutionContextScope *exe_scope) {
     STUB_LOG();
     return {};
   }
@@ -2131,8 +2132,9 @@ SwiftLanguageRuntime::GetByteStride(CompilerType type) {
 }
 
 llvm::Optional<size_t>
-SwiftLanguageRuntime::GetBitAlignment(CompilerType type) {
-  FORWARD(GetBitAlignment, type);
+SwiftLanguageRuntime::GetBitAlignment(CompilerType type,
+                                      ExecutionContextScope *exe_scope) {
+  FORWARD(GetBitAlignment, type, exe_scope);
 }
 
 bool SwiftLanguageRuntime::IsValidErrorValue(ValueObject &in_value) {

lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp

@@ -2181,9 +2181,10 @@ SwiftLanguageRuntimeImpl::GetByteStride(CompilerType type) {
 }
 
 llvm::Optional<size_t>
-SwiftLanguageRuntimeImpl::GetBitAlignment(CompilerType type) {
-  if (auto *type_info = GetTypeInfo(type, nullptr))
-    return type_info->getAlignment();
+SwiftLanguageRuntimeImpl::GetBitAlignment(CompilerType type,
+                                          ExecutionContextScope *exe_scope) {
+  if (auto *type_info = GetTypeInfo(type, exe_scope))
+    return type_info->getAlignment() * 8;
   return {};
 }
 

lldb/source/Target/SwiftLanguageRuntimeImpl.h

@@ -92,7 +92,8 @@ class SwiftLanguageRuntimeImpl {
   llvm::Optional<uint64_t> GetByteStride(CompilerType type);
 
   /// Ask Remote mirrors for the alignment of a Swift type.
-  llvm::Optional<size_t> GetBitAlignment(CompilerType type);
+  llvm::Optional<size_t> GetBitAlignment(CompilerType type,
+                                         ExecutionContextScope *exe_scope);
 
   SwiftLanguageRuntime::MetadataPromiseSP
   GetMetadataPromise(lldb::addr_t addr, ValueObject &for_object);