[lldb][Type Completion] Load C++ methods lazily from DWARF

clang/include/clang/AST/ExternalASTSource.h

@@ -150,6 +150,11 @@ class ExternalASTSource : public RefCountedBase<ExternalASTSource> {
   virtual bool
   FindExternalVisibleDeclsByName(const DeclContext *DC, DeclarationName Name);
 
+  virtual bool FindExternalVisibleMethodsByName(const DeclContext *DC,
+                                                DeclarationName Name) {
+    return false;
+  }
+
   /// Ensures that the table of all visible declarations inside this
   /// context is up to date.
   ///

clang/lib/Sema/SemaExprMember.cpp

@@ -715,6 +715,13 @@ static bool LookupMemberExprInRecord(Sema &SemaRef, LookupResult &R,
     }
   }
 
+  if (ExternalASTSource *Source =
+          DC->getParentASTContext().getExternalSource()) {
+    if (auto LookupName = R.getLookupName()) {
+      Source->FindExternalVisibleMethodsByName(DC, LookupName);
+    }
+  }
+
   // The record definition is complete, now look up the member.
   SemaRef.LookupQualifiedName(R, DC, SS);
 

lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp

@@ -11,6 +11,7 @@
 #include "ClangDeclVendor.h"
 #include "ClangModulesDeclVendor.h"
 
+#include "NameSearchContext.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleList.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
@@ -21,6 +22,7 @@
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
 #include "clang/Basic/SourceManager.h"
 
 #include "Plugins/ExpressionParser/Clang/ClangUtil.h"
@@ -615,6 +617,125 @@ bool ClangASTSource::IgnoreName(const ConstString name,
          name_string_ref.starts_with("_$");
 }
 
+bool ClangASTSource::FindExternalVisibleMethodsByName(
+    const clang::DeclContext *DC, clang::DeclarationName Name) {
+  if (!TypeSystemClang::UseRedeclCompletion())
+    return true;
+
+  SmallVector<clang::NamedDecl *> decls;
+  NameSearchContext context(*m_clang_ast_context, decls, Name, DC);
+  FindExternalVisibleMethods(context);
+
+  return true;
+}
+
+void ClangASTSource::FindExternalVisibleMethods(NameSearchContext &context) {
+  assert(m_ast_context);
+
+  const ConstString name(context.m_decl_name.getAsString().c_str());
+  CompilerDeclContext namespace_decl;
+  FindExternalVisibleMethods(context, lldb::ModuleSP(), namespace_decl);
+}
+
+bool ClangASTSource::CompilerDeclContextsMatch(
+    CompilerDeclContext candidate_decl_ctx, DeclContext const *context,
+    TypeSystemClang &ts) {
+  auto CDC1 = candidate_decl_ctx.GetTypeSystem()->DeclContextGetCompilerContext(
+      candidate_decl_ctx.GetOpaqueDeclContext());
+
+  // Member functions have at least 2 entries (1
+  // for method name, 1 for parent class)
+  assert(CDC1.size() > 1);
+
+  // drop last entry (which is function name)
+  CDC1.pop_back();
+
+  const auto CDC2 = ts.DeclContextGetCompilerContext(
+      const_cast<clang::DeclContext *>(context));
+
+  // Quick by-name check of the entire context hierarchy.
+  if (CDC1 == CDC2)
+    return true;
+
+  // Otherwise, check whether the 'candidate_decl_ctx' is a base class of
+  // 'context'.
+  auto const *candidate_context =
+      (static_cast<clang::DeclContext *>(
+           candidate_decl_ctx.GetOpaqueDeclContext()))
+          ->getParent();
+
+  auto const *candidate_cxx_record =
+      dyn_cast<clang::CXXRecordDecl>(candidate_context);
+  if (!candidate_cxx_record)
+    return false;
+
+  auto const *cxx_record = dyn_cast<clang::CXXRecordDecl>(context);
+  if (!cxx_record)
+    return false;
+
+  // cxx_record comes from user expression AST. So we need to get origin
+  // to compare against candidate_context.
+  auto orig = GetDeclOrigin(cxx_record);
+  if (!orig.Valid())
+    return false;
+
+  if (llvm::cast<CXXRecordDecl>(orig.decl)->isDerivedFrom(candidate_cxx_record))
+    return true;
+
+  return false;
+}
+
+void ClangASTSource::FindExternalVisibleMethods(
+    NameSearchContext &context, lldb::ModuleSP module_sp,
+    CompilerDeclContext &namespace_decl) {
+  assert(m_ast_context);
+
+  SymbolContextList sc_list;
+  const ConstString name(context.m_decl_name.getAsString().c_str());
+  if (!m_target)
+    return;
+
+  if (context.m_found_type)
+    return;
+
+  ModuleFunctionSearchOptions function_options;
+  function_options.include_inlines = false;
+  function_options.include_symbols = false;
+  m_target->GetImages().FindFunctions(name, lldb::eFunctionNameTypeMethod,
+                                      function_options, sc_list);
+
+  auto num_matches = sc_list.GetSize();
+  if (num_matches == 0)
+    return;
+
+  for (const SymbolContext &sym_ctx : sc_list) {
+    assert(sym_ctx.function);
+    CompilerDeclContext decl_ctx = sym_ctx.function->GetDeclContext();
+    if (!decl_ctx)
+      continue;
+
+    assert(decl_ctx.IsClassMethod());
+
+    if (!CompilerDeclContextsMatch(decl_ctx, context.m_decl_context,
+                                   context.m_clang_ts))
+      continue;
+
+    clang::CXXMethodDecl *src_method = llvm::cast<CXXMethodDecl>(
+        static_cast<clang::DeclContext *>(decl_ctx.GetOpaqueDeclContext()));
+    Decl *copied_decl = CopyDecl(src_method);
+
+    if (!copied_decl)
+      continue;
+
+    CXXMethodDecl *copied_method_decl = dyn_cast<CXXMethodDecl>(copied_decl);
+
+    if (!copied_method_decl)
+      continue;
+
+    context.AddNamedDecl(copied_method_decl);
+  }
+}
+
 void ClangASTSource::FindExternalVisibleDecls(
     NameSearchContext &context, lldb::ModuleSP module_sp,
     CompilerDeclContext &namespace_decl) {

lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h

@@ -87,6 +87,9 @@ class ClangASTSource : public ImporterBackedASTSource,
   bool FindExternalVisibleDeclsByName(const clang::DeclContext *DC,
                                       clang::DeclarationName Name) override;
 
+  bool FindExternalVisibleMethodsByName(const clang::DeclContext *DC,
+                                        clang::DeclarationName Name) override;
+
   /// Enumerate all Decls in a given lexical context.
   ///
   /// \param[in] DC
@@ -197,6 +200,7 @@ class ClangASTSource : public ImporterBackedASTSource,
   /// \param[in] context
   ///     The NameSearchContext to use when filing results.
   virtual void FindExternalVisibleDecls(NameSearchContext &context);
+  virtual void FindExternalVisibleMethods(NameSearchContext &context);
 
   clang::Sema *getSema();
 
@@ -219,6 +223,12 @@ class ClangASTSource : public ImporterBackedASTSource,
       return m_original.FindExternalVisibleDeclsByName(DC, Name);
     }
 
+    bool
+    FindExternalVisibleMethodsByName(const clang::DeclContext *DC,
+                                     clang::DeclarationName Name) override {
+      return m_original.FindExternalVisibleMethodsByName(DC, Name);
+    }
+
     void FindExternalLexicalDecls(
         const clang::DeclContext *DC,
         llvm::function_ref<bool(clang::Decl::Kind)> IsKindWeWant,
@@ -288,6 +298,9 @@ class ClangASTSource : public ImporterBackedASTSource,
   void FindExternalVisibleDecls(NameSearchContext &context,
                                 lldb::ModuleSP module,
                                 CompilerDeclContext &namespace_decl);
+  void FindExternalVisibleMethods(NameSearchContext &context,
+                                  lldb::ModuleSP module,
+                                  CompilerDeclContext &namespace_decl);
 
   /// Find all Objective-C methods matching a given selector.
   ///
@@ -364,6 +377,10 @@ class ClangASTSource : public ImporterBackedASTSource,
       NameSearchContext &context,
       DeclFromUser<const clang::ObjCInterfaceDecl> &origin_iface_decl);
 
+  bool CompilerDeclContextsMatch(CompilerDeclContext candidate_decl_ctx,
+                                 clang::DeclContext const *context,
+                                 TypeSystemClang &ts);
+
 protected:
   bool FindObjCMethodDeclsWithOrigin(
       NameSearchContext &context,

lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp

@@ -1337,6 +1337,13 @@ void ClangExpressionDeclMap::LookupFunction(
   }
 }
 
+void ClangExpressionDeclMap::FindExternalVisibleMethods(
+    NameSearchContext &context) {
+  assert(m_ast_context);
+
+  ClangASTSource::FindExternalVisibleMethods(context);
+}
+
 void ClangExpressionDeclMap::FindExternalVisibleDecls(
     NameSearchContext &context, lldb::ModuleSP module_sp,
     const CompilerDeclContext &namespace_decl) {

lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h

@@ -18,6 +18,7 @@
 #include "ClangASTSource.h"
 #include "ClangExpressionVariable.h"
 
+#include "Plugins/ExpressionParser/Clang/NameSearchContext.h"
 #include "lldb/Core/Value.h"
 #include "lldb/Expression/Materializer.h"
 #include "lldb/Symbol/SymbolContext.h"
@@ -266,6 +267,7 @@ class ClangExpressionDeclMap : public ClangASTSource {
   /// \param[in] context
   ///     The NameSearchContext that can construct Decls for this name.
   void FindExternalVisibleDecls(NameSearchContext &context) override;
+  void FindExternalVisibleMethods(NameSearchContext &context) override;
 
   /// Find all entities matching a given name in a given module/namespace,
   /// using a NameSearchContext to make Decls for them.

lldb/source/Plugins/ExpressionParser/Clang/ClangExternalASTSourceCallbacks.h

@@ -37,6 +37,11 @@ class ClangExternalASTSourceCallbacks : public ImporterBackedASTSource {
   bool FindExternalVisibleDeclsByName(const clang::DeclContext *DC,
                                       clang::DeclarationName Name) override;
 
+  bool FindExternalVisibleMethodsByName(const clang::DeclContext *DC,
+                                        clang::DeclarationName Name) override {
+    return false;
+  }
+
   void CompleteType(clang::TagDecl *tag_decl) override;
 
   void CompleteType(clang::ObjCInterfaceDecl *objc_decl) override;

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

@@ -2346,8 +2346,34 @@ bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
                       default_accessibility, layout_info);
 
     // Now parse any methods if there were any...
-    for (const DWARFDIE &die : member_function_dies)
-      dwarf->ResolveType(die);
+    for (const DWARFDIE &mem : member_function_dies) {
+      if (!TypeSystemClang::UseRedeclCompletion() ||
+          type_is_objc_object_or_interface) {
+        dwarf->ResolveType(mem);
+        continue;
+      }
+
+      ConstString mem_name(mem.GetName());
+      ConstString die_name(die.GetName());
+      const bool is_ctor = mem_name == die_name;
+      const bool is_virtual_method =
+          mem.GetAttributeValueAsUnsigned(
+              DW_AT_virtuality, DW_VIRTUALITY_none) > DW_VIRTUALITY_none;
+      const bool is_operator = mem_name.GetStringRef().starts_with("operator");
+      const bool is_static_method =
+          mem.GetFirstChild().GetAttributeValueAsUnsigned(DW_AT_artificial,
+                                                          0) == 0;
+
+      // FIXME: With RedeclCompletion, we currently don't have a good
+      // way to call `FindExternalVisibleMethods` from Clang
+      // for static functions, constructors or operators.
+      // So resolve them now.
+      //
+      // We want to resolve virtual methods now too because
+      // we set the method overrides below.
+      if (is_ctor || is_operator || is_virtual_method || is_static_method)
+        dwarf->ResolveType(mem);
+    }
 
     if (type_is_objc_object_or_interface) {
       ConstString class_name(clang_type.GetTypeName());

lldb/test/API/commands/expression/completion/TestExprCompletion.py

@@ -13,6 +13,7 @@
 class CommandLineExprCompletionTestCase(TestBase):
     NO_DEBUG_INFO_TESTCASE = True
 
+    @expectedFailureAll(setting=('plugin.typesystem.clang.experimental-redecl-completion', 'true'))
     def test_expr_completion(self):
         self.build()
         self.main_source = "main.cpp"

lldb/test/API/commands/expression/context-object/TestContextObject.py

@@ -5,9 +5,29 @@
 import lldb
 import lldbsuite.test.lldbutil as lldbutil
 from lldbsuite.test.lldbtest import *
-
+from lldbsuite.test.decorators import *
 
 class ContextObjectTestCase(TestBase):
+    @expectedFailureAll(setting=('plugin.typesystem.clang.experimental-redecl-completion', 'true'))
+    def test_context_object_eval_function(self):
+        """Tests expression evaluation of functions in context of an object."""
+        self.build()
+
+        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+            self, "// Break here", self.main_source_spec
+        )
+        frame = thread.GetFrameAtIndex(0)
+        for obj in "cpp_struct", "cpp_struct_ref":
+            obj_val = frame.FindVariable(obj)
+            self.assertTrue(obj_val.IsValid())
+
+            # Test functions evaluation
+            value = obj_val.EvaluateExpression("function()")
+            self.assertTrue(value.IsValid())
+            self.assertSuccess(value.GetError())
+            self.assertEqual(value.GetValueAsSigned(), 2222)
+
+
     def test_context_object(self):
         """Tests expression evaluation in context of an object."""
         self.build()
@@ -35,12 +55,6 @@ def test_context_object(self):
             self.assertSuccess(value.GetError())
             self.assertEqual(value.GetValueAsSigned(), 1111)
 
-            # Test functions evaluation
-            value = obj_val.EvaluateExpression("function()")
-            self.assertTrue(value.IsValid())
-            self.assertSuccess(value.GetError())
-            self.assertEqual(value.GetValueAsSigned(), 2222)
-
             # Test that we retrieve the right global
             value = obj_val.EvaluateExpression("global.field")
             self.assertTrue(value.IsValid())

lldb/test/API/commands/expression/import-std-module/empty-module/TestEmptyStdModule.py

@@ -15,6 +15,7 @@ class ImportStdModule(TestBase):
     @add_test_categories(["libc++"])
     @skipIfRemote
     @skipIf(compiler=no_match("clang"))
+    @expectedFailureAll(setting=('plugin.typesystem.clang.experimental-redecl-completion', 'true'))
     def test(self):
         self.build()
 

lldb/test/API/commands/expression/pr35310/TestExprsBug35310.py

@@ -12,6 +12,7 @@ def setUp(self):
         self.main_source = "main.cpp"
         self.main_source_spec = lldb.SBFileSpec(self.main_source)
 
+    @expectedFailureAll(setting=('plugin.typesystem.clang.experimental-redecl-completion', 'true'))
     def test_issue35310(self):
         """Test invoking functions with non-standard linkage names.
 

lldb/test/API/lang/cpp/function-ref-qualifiers/TestCppFunctionRefQualifiers.py

@@ -34,11 +34,11 @@ def test(self):
         self.expect_expr("Foo{}.func()", result_type="int64_t", result_value="3")
 
         self.filecheck("target modules dump ast", __file__)
-        # CHECK:      |-CXXMethodDecl {{.*}} func 'uint32_t () const &'
-        # CHECK-NEXT: | `-AsmLabelAttr {{.*}}
-        # CHECK-NEXT: |-CXXMethodDecl {{.*}} func 'int64_t () const &&'
-        # CHECK-NEXT: | `-AsmLabelAttr {{.*}}
-        # CHECK-NEXT: |-CXXMethodDecl {{.*}} func 'uint32_t () &'
-        # CHECK-NEXT: | `-AsmLabelAttr {{.*}}
-        # CHECK-NEXT: `-CXXMethodDecl {{.*}} func 'int64_t () &&'
-        # CHECK-NEXT:   `-AsmLabelAttr {{.*}}
+        # CHECK-DAG: CXXMethodDecl {{.*}} func 'uint32_t () const &'
+        # CHECK-DAG: `-AsmLabelAttr {{.*}}
+        # CHECK-DAG: CXXMethodDecl {{.*}} func 'int64_t () const &&'
+        # CHECK-DAG: `-AsmLabelAttr {{.*}}
+        # CHECK-DAG: CXXMethodDecl {{.*}} func 'uint32_t () &'
+        # CHECK-DAG: `-AsmLabelAttr {{.*}}
+        # CHECK-DAG: CXXMethodDecl {{.*}} func 'int64_t () &&'
+        # CHECK-DAG: `-AsmLabelAttr {{.*}}

lldb/test/API/python_api/class_members/TestSBTypeClassMembers.py

@@ -19,6 +19,7 @@ def setUp(self):
         self.source = "main.mm"
         self.line = line_number(self.source, "// set breakpoint here")
 
+    @expectedFailureAll(setting=('plugin.typesystem.clang.experimental-redecl-completion', 'true'))
     @skipUnlessDarwin
     def test(self):
         """Test SBType APIs to fetch member function types."""