[lldb][DWARFASTParser] Don't pass CompilerType by non-const reference in the DWARFASTParserClang APIs

[Michael137]

The CompilerType is just a wrapper around two pointers, and there is no usage of the CompilerType where those are expected to change underneath the caller.

To make the interface more straightforward to reason about, this patch changes all instances of CompilerType& to const CompilerType& around the DWARFASTParserClang APIs.

We could probably pass these by-value, but all other APIs don't, and this patch just makes the parameter passing convention consistent with the rest of the file.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Michael Buch (Michael137)

Changes

The CompilerType is just a wrapper around two pointers, and there is no usage of the CompilerType where those are expected to change underneath the caller.

To make the interface more straightforward to reason about, this patch changes all instances of CompilerType& to const CompilerType& around the DWARFASTParserClang APIs.

We could probably pass these by-value, but all other APIs don't, and this patch just makes the parameter passing convention consistent with the rest of the file.

---

Full diff: https://github.com/llvm/llvm-project/pull/103245.diff

3 Files Affected:

• (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h (+1-1)
• (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp (+9-8)
• (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h (+9-9)

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h
index abaeb2502cbbdc..636ff4b5cf11dc 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParser.h
@@ -45,7 +45,7 @@ class DWARFASTParser {
                                            const AddressRange &range) = 0;
 
   virtual bool CompleteTypeFromDWARF(const DWARFDIE &die, Type *type,
-                                     CompilerType &compiler_type) = 0;
+                                     const CompilerType &compiler_type) = 0;
 
   virtual CompilerDecl GetDeclForUIDFromDWARF(const DWARFDIE &die) = 0;
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index 86b3117f361cd1..3c58be26c266bb 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -2057,7 +2057,7 @@ bool DWARFASTParserClang::ParseTemplateParameterInfos(
 
 bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
                                              lldb_private::Type *type,
-                                             CompilerType &clang_type) {
+                                             const CompilerType &clang_type) {
   const dw_tag_t tag = die.Tag();
   SymbolFileDWARF *dwarf = die.GetDWARF();
 
@@ -2152,7 +2152,7 @@ bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
 
 bool DWARFASTParserClang::CompleteEnumType(const DWARFDIE &die,
                                            lldb_private::Type *type,
-                                           CompilerType &clang_type) {
+                                           const CompilerType &clang_type) {
   if (TypeSystemClang::StartTagDeclarationDefinition(clang_type)) {
     if (die.HasChildren()) {
       bool is_signed = false;
@@ -2165,9 +2165,9 @@ bool DWARFASTParserClang::CompleteEnumType(const DWARFDIE &die,
   return (bool)clang_type;
 }
 
-bool DWARFASTParserClang::CompleteTypeFromDWARF(const DWARFDIE &die,
-                                                lldb_private::Type *type,
-                                                CompilerType &clang_type) {
+bool DWARFASTParserClang::CompleteTypeFromDWARF(
+    const DWARFDIE &die, lldb_private::Type *type,
+    const CompilerType &clang_type) {
   SymbolFileDWARF *dwarf = die.GetDWARF();
 
   std::lock_guard<std::recursive_mutex> guard(
@@ -2244,7 +2244,7 @@ DWARFASTParserClang::GetDeclContextContainingUIDFromDWARF(const DWARFDIE &die) {
 }
 
 size_t DWARFASTParserClang::ParseChildEnumerators(
-    lldb_private::CompilerType &clang_type, bool is_signed,
+    const lldb_private::CompilerType &clang_type, bool is_signed,
     uint32_t enumerator_byte_size, const DWARFDIE &parent_die) {
   if (!parent_die)
     return 0;
@@ -3032,7 +3032,7 @@ void DWARFASTParserClang::ParseSingleMember(
 }
 
 bool DWARFASTParserClang::ParseChildMembers(
-    const DWARFDIE &parent_die, CompilerType &class_clang_type,
+    const DWARFDIE &parent_die, const CompilerType &class_clang_type,
     std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> &base_classes,
     std::vector<DWARFDIE> &member_function_dies,
     std::vector<DWARFDIE> &contained_type_dies,
@@ -3763,7 +3763,8 @@ bool DWARFASTParserClang::ShouldCreateUnnamedBitfield(
 }
 
 void DWARFASTParserClang::ParseRustVariantPart(
-    DWARFDIE &die, const DWARFDIE &parent_die, CompilerType &class_clang_type,
+    DWARFDIE &die, const DWARFDIE &parent_die,
+    const CompilerType &class_clang_type,
     const lldb::AccessType default_accesibility,
     ClangASTImporter::LayoutInfo &layout_info) {
   assert(die.Tag() == llvm::dwarf::DW_TAG_variant_part);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
index 4b0ae026bce7e9..ae6720608121f5 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
@@ -61,10 +61,10 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
                          const lldb_private::plugin::dwarf::DWARFDIE &die,
                          const lldb_private::AddressRange &func_range) override;
 
-  bool
-  CompleteTypeFromDWARF(const lldb_private::plugin::dwarf::DWARFDIE &die,
-                        lldb_private::Type *type,
-                        lldb_private::CompilerType &compiler_type) override;
+  bool CompleteTypeFromDWARF(
+      const lldb_private::plugin::dwarf::DWARFDIE &die,
+      lldb_private::Type *type,
+      const lldb_private::CompilerType &compiler_type) override;
 
   lldb_private::CompilerDecl GetDeclForUIDFromDWARF(
       const lldb_private::plugin::dwarf::DWARFDIE &die) override;
@@ -178,7 +178,7 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
 
   bool ParseChildMembers(
       const lldb_private::plugin::dwarf::DWARFDIE &die,
-      lldb_private::CompilerType &class_compiler_type,
+      const lldb_private::CompilerType &class_compiler_type,
       std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> &base_classes,
       std::vector<lldb_private::plugin::dwarf::DWARFDIE> &member_function_dies,
       std::vector<lldb_private::plugin::dwarf::DWARFDIE> &contained_type_dies,
@@ -196,7 +196,7 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
                        unsigned &type_quals);
 
   size_t ParseChildEnumerators(
-      lldb_private::CompilerType &compiler_type, bool is_signed,
+      const lldb_private::CompilerType &compiler_type, bool is_signed,
       uint32_t enumerator_byte_size,
       const lldb_private::plugin::dwarf::DWARFDIE &parent_die);
 
@@ -362,10 +362,10 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
 
   bool CompleteRecordType(const lldb_private::plugin::dwarf::DWARFDIE &die,
                           lldb_private::Type *type,
-                          lldb_private::CompilerType &clang_type);
+                          const lldb_private::CompilerType &clang_type);
   bool CompleteEnumType(const lldb_private::plugin::dwarf::DWARFDIE &die,
                         lldb_private::Type *type,
-                        lldb_private::CompilerType &clang_type);
+                        const lldb_private::CompilerType &clang_type);
 
   lldb::TypeSP
   ParseTypeModifier(const lldb_private::SymbolContext &sc,
@@ -467,7 +467,7 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
   void
   ParseRustVariantPart(lldb_private::plugin::dwarf::DWARFDIE &die,
                        const lldb_private::plugin::dwarf::DWARFDIE &parent_die,
-                       lldb_private::CompilerType &class_clang_type,
+                       const lldb_private::CompilerType &class_clang_type,
                        const lldb::AccessType default_accesibility,
                        lldb_private::ClangASTImporter::LayoutInfo &layout_info);
 };