[clang-repl] Remove memory leak of ASTContext/TargetMachine.

[sunho]

Summary

Removes memory leak of ASTContext and TargetMachine. When DisableFree is turned on, it intentionally leaks these instances as they can be trivially deallocated. This patch turns this off and delete Parser instance early so that they will not reference dangling pargma headers.

Asan shouldn't detect these as leaks normally, since burypointer is called for them. But, every invocation of incremental parser createa an additional leak of TargetMachine. If there are many invocations within a single test case, we easily reach number of leaks exceeding kGraveYardMaxSize (which is 12) and leaks start to get reported by asan buildbots.

[sunho]

This comment was removed by sunho.

[sunho]

Remove leaks of targetmachine too.

[sunho]

@Purva-Chaudhari Could you check this out? Basically, this should allow even long execute.cpp test case to be ran without asan failures.

[sunho]

format

[Purva-Chaudhari]

In D127991#3589949, @sunho wrote:

@Purva-Chaudhari Could you check this out? Basically, this should allow even long execute.cpp test case to be ran without asan failures.

Sure

[Purva-Chaudhari]

Asan tests passing! Solves the memory leak issue for original as well as modified version of execute.cpp (Commit issue solved )

[sunho]

In D127991#3591355, @Purva-Chaudhari wrote:

Asan tests passing! Solves the memory leak issue for original as well as modified version of execute.cpp (Commit issue solved )

Nice!!

[v.g.vassilev]

Lgtm!

clang/lib/Interpreter/IncrementalParser.cpp

if (Err)
     return;
   CI->ExecuteAction(*Act);
   Consumer = &CI->getASTConsumer();
   P.reset(
       new Parser(CI->getPreprocessor(), CI->getSema(), /*SkipBodies=*/false));
   P->Initialize();
 }
 
-IncrementalParser::~IncrementalParser() { Act->FinalizeAction(); }
+IncrementalParser::~IncrementalParser() {
+  P.reset();
+  Act->FinalizeAction();
+}
 
 llvm::Expected<PartialTranslationUnit &>
 IncrementalParser::ParseOrWrapTopLevelDecl() {
   // Recover resources if we crash before exiting this method.
   Sema &S = CI->getSema();
   llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(&S);
   Sema::GlobalEagerInstantiationScope GlobalInstantiations(S, /*Enabled=*/true);
   Sema::LocalEagerInstantiationScope LocalInstantiations(S);

clang/lib/Interpreter/Interpreter.cpp

return llvm::createStringError(llvm::errc::not_supported,
                                    "Target is missing");
 
   Clang->getTarget().adjust(Clang->getDiagnostics(), Clang->getLangOpts());
 
   // Don't clear the AST before backend codegen since we do codegen multiple
   // times, reusing the same AST.
   Clang->getCodeGenOpts().ClearASTBeforeBackend = false;
 
+  Clang->getFrontendOpts().DisableFree = false;
+  Clang->getCodeGenOpts().DisableFree = false;
+
   return std::move(Clang);
 }
 
 } // anonymous namespace
 
 llvm::Expected<std::unique_ptr<CompilerInstance>>
 IncrementalCompilerBuilder::create(std::vector<const char *> &ClangArgv) {