[lldb] Extend FindTypes to optionally search by mangled type name

Swift types have mangled type names. This adds functionality to look
up those types through the FindTypes API by searching for the mangled
type name instead of the regular name.

Author: augusto2112

lldb/include/lldb/Symbol/Type.h

@@ -84,6 +84,9 @@ FLAGS_ENUM(TypeQueryOptions){
     /// matching type is found. When false, the type query should find all
     /// matching types.
     e_find_one = (1u << 4),
+    // If set, treat TypeQuery::m_name as a mangled name that should be
+    // searched.
+    e_search_by_mangled_name = (1u << 5),
 };
 LLDB_MARK_AS_BITMASK_ENUM(TypeQueryOptions)
 
@@ -300,6 +303,19 @@ class TypeQuery {
       m_options &= ~e_find_one;
   }
 
+  /// Returns true if the type query is supposed to treat the name to be
+  /// searched as a mangled name.
+  bool GetSearchByMangledName() const {
+    return (m_options & e_search_by_mangled_name) != 0;
+  }
+
+  void SetSearchByMangledName(bool b) {
+    if (b)
+      m_options |= e_search_by_mangled_name;
+    else
+      m_options &= ~e_search_by_mangled_name;
+  }
+
   /// Access the internal compiler context array.
   ///
   /// Clients can use this to populate the context manually.

lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp

@@ -199,9 +199,9 @@ DWARFDIE::LookupDeepestBlock(lldb::addr_t address) const {
   return result;
 }
 
-const char *DWARFDIE::GetMangledName() const {
+const char *DWARFDIE::GetMangledName(bool substitute_name_allowed) const {
   if (IsValid())
-    return m_die->GetMangledName(m_cu);
+    return m_die->GetMangledName(m_cu, substitute_name_allowed);
   else
     return nullptr;
 }

lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.h

@@ -28,7 +28,7 @@ class DWARFDIE : public DWARFBaseDIE {
   // Accessors
 
   // Accessing information about a DIE
-  const char *GetMangledName() const;
+  const char *GetMangledName(bool substitute_name_allowed = true) const;
 
   const char *GetPubname() const;
 

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

@@ -2758,6 +2758,20 @@ void SymbolFileDWARF::FindTypes(const TypeQuery &query, TypeResults &results) {
         return true; // Keep iterating over index types, language mismatch.
     }
 
+    // Since mangled names are unique, we only need to check if the names are
+    // the same.
+    if (query.GetSearchByMangledName()) {
+      if (die.GetMangledName(/*substitute_name_allowed=*/false) !=
+          query.GetTypeBasename().GetStringRef())
+        return true; // Keep iterating over index types, mangled name mismatch.
+      if (Type *matching_type = ResolveType(die, true, true)) {
+        results.InsertUnique(matching_type->shared_from_this());
+        return !results.Done(query); // Keep iterating if we aren't done.
+      }
+      return true; // Keep iterating over index types, weren't able to resolve
+                   // this type
+    }
+
     // Check the context matches
     std::vector<lldb_private::CompilerContext> die_context;
     if (query.GetModuleSearch())

lldb/test/Shell/SymbolFile/DWARF/debug-types-mangled-name.ll

@@ -0,0 +1,63 @@
+; Test finding types by CompilerContext.
+; REQUIRES: aarch64
+; RUN: llc %s -filetype=obj -o %t.o
+; RUN: lldb-test symbols %t.o -find=type --mangled-name=UniqueDifferentName | FileCheck %s 
+;
+; NORESULTS: Found 0 types
+; CHECK: Found 1 types:
+; CHECK: struct DifferentName {
+; CHECK-NEXT:     int i;
+; CHECK-NEXT: }
+
+source_filename = "t.c"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32"
+target triple = "arm64-unknown-linux-gnu"
+
+%struct.SameName = type { i32 }
+%struct.DifferentName = type { i32 }
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @main() #0 !dbg !10 {
+entry:
+  %retval = alloca i32, align 4
+  %s = alloca %struct.SameName, align 4
+  %d = alloca %struct.DifferentName, align 4
+  store i32 0, ptr %retval, align 4
+    #dbg_declare(ptr %s, !16, !DIExpression(), !20)
+    #dbg_declare(ptr %d, !21, !DIExpression(), !25)
+  ret i32 0, !dbg !26
+}
+
+attributes #0 = { noinline nounwind optnone uwtable "frame-pointer"="non-leaf" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+fp-armv8,+neon,+v8a,-fmv" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "t.c", directory: "/")
+!2 = !{i32 7, !"Dwarf Version", i32 5}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 8, !"PIC Level", i32 2}
+!6 = !{i32 7, !"PIE Level", i32 2}
+!7 = !{i32 7, !"uwtable", i32 2}
+!8 = !{i32 7, !"frame-pointer", i32 1}
+!9 = !{!""}
+!10 = distinct !DISubprogram(name: "main", scope: !11, file: !11, line: 9, type: !12, scopeLine: 9, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !15)
+!11 = !DIFile(filename: "t.c", directory: "")
+!12 = !DISubroutineType(types: !13)
+!13 = !{!14}
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !{}
+!16 = !DILocalVariable(name: "s", scope: !10, file: !11, line: 10, type: !17)
+!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "SameName", file: !11, line: 1, size: 32, elements: !18, runtimeLang: DW_LANG_Swift, identifier: "SameName")
+!18 = !{!19}
+!19 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !17, file: !11, line: 2, baseType: !14, size: 32)
+!20 = !DILocation(line: 10, column: 19, scope: !10)
+!21 = !DILocalVariable(name: "d", scope: !10, file: !11, line: 11, type: !22)
+!22 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "DifferentName", file: !11, line: 5, size: 32, elements: !23, runtimeLang: DW_LANG_Swift, identifier: "UniqueDifferentName")
+!23 = !{!24}
+!24 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !22, file: !11, line: 6, baseType: !14, size: 32)
+!25 = !DILocation(line: 11, column: 24, scope: !10)
+!26 = !DILocation(line: 12, column: 3, scope: !10)

lldb/tools/lldb-test/lldb-test.cpp

@@ -13,6 +13,7 @@
 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
 #include "lldb/Breakpoint/BreakpointLocation.h"
 #include "lldb/Core/Debugger.h"
+#include "lldb/Core/Mangled.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Expression/IRMemoryMap.h"
@@ -23,6 +24,7 @@
 #include "lldb/Symbol/LineTable.h"
 #include "lldb/Symbol/SymbolFile.h"
 #include "lldb/Symbol/Symtab.h"
+#include "lldb/Symbol/Type.h"
 #include "lldb/Symbol/TypeList.h"
 #include "lldb/Symbol/TypeMap.h"
 #include "lldb/Symbol/VariableList.h"
@@ -179,6 +181,10 @@ static cl::opt<FindType> Find(
 
 static cl::opt<std::string> Name("name", cl::desc("Name to find."),
                                  cl::sub(SymbolsSubcommand));
+static cl::opt<std::string> MangledName(
+    "mangled-name",
+    cl::desc("Mangled name to find. Only compatible when searching types"),
+    cl::sub(SymbolsSubcommand));
 static cl::opt<bool>
     Regex("regex",
           cl::desc("Search using regular expressions (available for variables "
@@ -468,6 +474,9 @@ static lldb::DescriptionLevel GetDescriptionLevel() {
 }
 
 Error opts::symbols::findFunctions(lldb_private::Module &Module) {
+  if (!MangledName.empty())
+    return make_string_error("Cannot search functions by mangled name.");
+
   SymbolFile &Symfile = *Module.GetSymbolFile();
   SymbolContextList List;
   auto compiler_context = parseCompilerContext();
@@ -529,6 +538,8 @@ Error opts::symbols::findBlocks(lldb_private::Module &Module) {
   assert(!Regex);
   assert(!File.empty());
   assert(Line != 0);
+  if (!MangledName.empty())
+    return make_string_error("Cannot search blocks by mangled name.");
 
   SymbolContextList List;
 
@@ -563,6 +574,9 @@ Error opts::symbols::findBlocks(lldb_private::Module &Module) {
 }
 
 Error opts::symbols::findNamespaces(lldb_private::Module &Module) {
+  if (!MangledName.empty())
+    return make_string_error("Cannot search namespaces by mangled name.");
+
   SymbolFile &Symfile = *Module.GetSymbolFile();
   Expected<CompilerDeclContext> ContextOr = getDeclContext(Symfile);
   if (!ContextOr)
@@ -585,11 +599,15 @@ Error opts::symbols::findTypes(lldb_private::Module &Module) {
   Expected<CompilerDeclContext> ContextOr = getDeclContext(Symfile);
   if (!ContextOr)
     return ContextOr.takeError();
+  ;
 
   TypeQueryOptions Opts = TypeQueryOptions::e_module_search;
   if (FindInAnyModule)
     Opts |= TypeQueryOptions::e_ignore_modules;
   TypeResults results;
+  if (!Name.empty() && !MangledName.empty())
+    return make_string_error("Cannot search by both name and mangled name.");
+
   if (!Name.empty()) {
     if (ContextOr->IsValid()) {
       TypeQuery query(*ContextOr, ConstString(Name), Opts);
@@ -602,6 +620,20 @@ Error opts::symbols::findTypes(lldb_private::Module &Module) {
         query.AddLanguage(Language::GetLanguageTypeFromString(Language));
       Symfile.FindTypes(query, results);
     }
+  } else if (!MangledName.empty()) {
+    Opts = TypeQueryOptions::e_search_by_mangled_name;
+    if (ContextOr->IsValid()) {
+      TypeQuery query(*ContextOr, ConstString(MangledName), Opts);
+      if (!Language.empty())
+        query.AddLanguage(Language::GetLanguageTypeFromString(Language));
+      Symfile.FindTypes(query, results);
+    } else {
+      TypeQuery query(MangledName, Opts);
+      if (!Language.empty())
+        query.AddLanguage(Language::GetLanguageTypeFromString(Language));
+      Symfile.FindTypes(query, results);
+    }
+
   } else {
     TypeQuery query(parseCompilerContext(), Opts);
     if (!Language.empty())
@@ -619,6 +651,9 @@ Error opts::symbols::findTypes(lldb_private::Module &Module) {
 }
 
 Error opts::symbols::findVariables(lldb_private::Module &Module) {
+  if (!MangledName.empty())
+    return make_string_error("Cannot search variables by mangled name.");
+
   SymbolFile &Symfile = *Module.GetSymbolFile();
   VariableList List;
   if (Regex) {