[lldb] Avoid force loading symbols in statistics collection

lldb/include/lldb/Symbol/ObjectFile.h

@@ -319,7 +319,7 @@ class ObjectFile : public std::enable_shared_from_this<ObjectFile>,
   ///
   /// \return
   ///     The symbol table for this object file.
-  Symtab *GetSymtab();
+  Symtab *GetSymtab(bool can_create = true);
 
   /// Parse the symbol table into the provides symbol table object.
   ///

lldb/include/lldb/Symbol/SymbolFile.h

@@ -144,7 +144,7 @@ class SymbolFile : public PluginInterface {
   virtual uint32_t GetNumCompileUnits() = 0;
   virtual lldb::CompUnitSP GetCompileUnitAtIndex(uint32_t idx) = 0;
 
-  virtual Symtab *GetSymtab() = 0;
+  virtual Symtab *GetSymtab(bool can_create = true) = 0;
 
   virtual lldb::LanguageType ParseLanguage(CompileUnit &comp_unit) = 0;
   /// Return the Xcode SDK comp_unit was compiled against.
@@ -533,7 +533,7 @@ class SymbolFileCommon : public SymbolFile {
     return m_abilities;
   }
 
-  Symtab *GetSymtab() override;
+  Symtab *GetSymtab(bool can_create = true) override;
 
   ObjectFile *GetObjectFile() override { return m_objfile_sp.get(); }
   const ObjectFile *GetObjectFile() const override {

lldb/include/lldb/Symbol/SymbolFileOnDemand.h

@@ -186,7 +186,9 @@ class SymbolFileOnDemand : public lldb_private::SymbolFile {
 
   uint32_t GetAbilities() override;
 
-  Symtab *GetSymtab() override { return m_sym_file_impl->GetSymtab(); }
+  Symtab *GetSymtab(bool can_create = true) override {
+    return m_sym_file_impl->GetSymtab(can_create);
+  }
 
   ObjectFile *GetObjectFile() override {
     return m_sym_file_impl->GetObjectFile();

lldb/source/Core/Module.cpp

@@ -997,7 +997,7 @@ SymbolFile *Module::GetSymbolFile(bool can_create, Stream *feedback_strm) {
 
 Symtab *Module::GetSymtab(bool can_create) {
   if (SymbolFile *symbols = GetSymbolFile(can_create))
-    return symbols->GetSymtab();
+    return symbols->GetSymtab(can_create);
   return nullptr;
 }
 

lldb/source/Symbol/ObjectFile.cpp

@@ -734,10 +734,9 @@ void llvm::format_provider<ObjectFile::Strata>::format(
   }
 }
 
-
-Symtab *ObjectFile::GetSymtab() {
+Symtab *ObjectFile::GetSymtab(bool can_create) {
   ModuleSP module_sp(GetModule());
-  if (module_sp) {
+  if (module_sp && can_create) {
     // We can't take the module lock in ObjectFile::GetSymtab() or we can
     // deadlock in DWARF indexing when any file asks for the symbol table from
     // an object file. This currently happens in the preloading of symbols in

lldb/source/Symbol/SymbolFile.cpp

@@ -152,10 +152,10 @@ void SymbolFile::AssertModuleLock() {
 
 SymbolFile::RegisterInfoResolver::~RegisterInfoResolver() = default;
 
-Symtab *SymbolFileCommon::GetSymtab() {
+Symtab *SymbolFileCommon::GetSymtab(bool can_create) {
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   // Fetch the symtab from the main object file.
-  auto *symtab = GetMainObjectFile()->GetSymtab();
+  auto *symtab = GetMainObjectFile()->GetSymtab(can_create);
   if (m_symtab != symtab) {
     m_symtab = symtab;
 

lldb/unittests/Symbol/LineTableTest.cpp

@@ -58,7 +58,7 @@ class FakeSymbolFile : public SymbolFile {
   uint32_t CalculateAbilities() override { return UINT32_MAX; }
   uint32_t GetNumCompileUnits() override { return 1; }
   CompUnitSP GetCompileUnitAtIndex(uint32_t) override { return m_cu_sp; }
-  Symtab *GetSymtab() override { return nullptr; }
+  Symtab *GetSymtab(bool can_create = true) override { return nullptr; }
   LanguageType ParseLanguage(CompileUnit &) override { return eLanguageTypeC; }
   size_t ParseFunctions(CompileUnit &) override { return 0; }
   bool ParseLineTable(CompileUnit &) override { return true; }

lldb/unittests/Symbol/SymtabTest.cpp

@@ -721,7 +721,7 @@ TEST_F(SymtabTest, TestDecodeCStringMaps) {
   ASSERT_NE(symbol, nullptr);
 }
 
-TEST_F(SymtabTest, TestSymtabCreatedOnDemand) {
+TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
   auto ExpectedFile = TestFile::fromYaml(R"(
 --- !ELF
 FileHeader:
@@ -749,10 +749,20 @@ TEST_F(SymtabTest, TestSymtabCreatedOnDemand) {
   ASSERT_THAT_EXPECTED(ExpectedFile, llvm::Succeeded());
   auto module_sp = std::make_shared<Module>(ExpectedFile->moduleSpec());
 
-  // The symbol table should not be loaded by default.
+  // The symbol file should not be created by default.
   Symtab *module_symtab = module_sp->GetSymtab(/*can_create=*/false);
   ASSERT_EQ(module_symtab, nullptr);
 
+  // Even if the symbol file is created, the symbol table should not be created by default.
+
+  // TODO:
+  // I need to create a symbol file here, but without causing it to parse the symbol table.
+  // See next line as a failed attempt.
+
+  // module_sp->GetSymbolFile(/*can_create=*/true); // Cannot do this because it will parse the symbol table.
+  module_symtab = module_sp->GetSymtab(/*can_create=*/false);
+  ASSERT_EQ(module_symtab, nullptr);
+
   // But it should be created on demand.
   module_symtab = module_sp->GetSymtab(/*can_create=*/true);
   ASSERT_NE(module_symtab, nullptr);