Add unit test

Author: royitaqi

lldb/unittests/Symbol/SymtabTest.cpp

@@ -721,7 +721,7 @@ TEST_F(SymtabTest, TestDecodeCStringMaps) {
   ASSERT_NE(symbol, nullptr);
 }
 
-TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
+TEST_F(SymtabTest, TestSymbolFileCreatedOnDemand) {
   auto ExpectedFile = TestFile::fromYaml(R"(
 --- !ELF
 FileHeader:
@@ -753,16 +753,6 @@ TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
   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);
@@ -771,3 +761,74 @@ TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
   Symtab *cached_module_symtab = module_sp->GetSymtab(/*can_create=*/false);
   ASSERT_EQ(module_symtab, cached_module_symtab);
 }
+
+TEST_F(SymtabTest, TestSymbolTableCreatedOnDemand) {
+  const char *yamldata = R"(
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_386
+DWARF:
+  debug_abbrev:
+    - Table:
+        - Code:            0x00000001
+          Tag:             DW_TAG_compile_unit
+          Children:        DW_CHILDREN_no
+          Attributes:
+            - Attribute:       DW_AT_addr_base
+              Form:            DW_FORM_sec_offset
+  debug_info:
+    - Version:         5
+      AddrSize:        4
+      UnitType:        DW_UT_compile
+      Entries:
+        - AbbrCode:        0x00000001
+          Values:
+            - Value:           0x8 # Offset of the first Address past the header
+        - AbbrCode:        0x0
+  debug_addr:
+    - Version: 5
+      AddressSize: 4
+      Entries:
+        - Address: 0x1234
+        - Address: 0x5678
+  debug_line:
+    - Length:          42
+      Version:         2
+      PrologueLength:  36
+      MinInstLength:   1
+      DefaultIsStmt:   1
+      LineBase:        251
+      LineRange:       14
+      OpcodeBase:      13
+      StandardOpcodeLengths: [ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 ]
+      IncludeDirs:
+        - '/tmp'
+      Files:
+        - Name:            main.cpp
+          DirIdx:          1
+          ModTime:         0
+          Length:          0
+)";
+  llvm::Expected<TestFile> file = TestFile::fromYaml(yamldata);
+  EXPECT_THAT_EXPECTED(file, llvm::Succeeded());
+  auto module_sp = std::make_shared<Module>(file->moduleSpec());
+
+  SymbolFile* symbol_file = module_sp->GetSymbolFile();
+  // At this point, the symbol table is not created. This is because the above yaml data contains the necessary sections in order for SymbolFileDWARF::CalculateAbilities() to identify all abilities,
+  // saving the code from calling SymbolFileDWARFDebugMap::CalculateAbilities(), which eventually loads the symbol table, which we don't want.
+
+  // The symbol table should not be created if asked not to.
+  Symtab* symtab = symbol_file->GetSymtab(/*can_create=*/false);
+  ASSERT_EQ(symtab, nullptr);
+
+  // But it should be created on demand.
+  symtab = symbol_file->GetSymtab(/*can_create=*/true);
+  ASSERT_NE(symtab, nullptr);
+
+  // And we should be able to get it again once it has been created.
+  symtab = symbol_file->GetSymtab(/*can_create=*/false);
+  ASSERT_NE(symtab, nullptr);
+}