[ORC] Replace ThreadSafeContext::getContext with withContextDo. (#146819)

This removes ThreadSafeContext::Lock, ThreadSafeContext::getLock, and
ThreadSafeContext::getContext, and replaces them with a
ThreadSafeContext::withContextDo method (and const override).

The new method can be used to access an existing
ThreadSafeContext-wrapped LLVMContext in a safe way:

ThreadSafeContext TSCtx = ... ;
TSCtx.withContextDo([](LLVMContext *Ctx) {
  // this closure has exclusive access to Ctx.
});

The new API enforces correct locking, whereas the old APIs relied on
manual locking (which almost no in-tree code preformed, relying instead
on incidental exclusive access to the ThreadSafeContext).

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/ThreadSafeModule.cpp b/llvm/lib/ExecutionEngine/Orc/ThreadSafeModule.cpp
index 2e128dd23744..c927f2149469 100644
--- a/llvm/lib/ExecutionEngine/Orc/ThreadSafeModule.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ThreadSafeModule.cpp
@@ -53,9 +53,11 @@ ThreadSafeModule cloneToNewContext(const ThreadSafeModule &TSM,
         "cloned module buffer");
     ThreadSafeContext NewTSCtx(std::make_unique<LLVMContext>());
 
-    auto ClonedModule = cantFail(
-        parseBitcodeFile(ClonedModuleBufferRef, *NewTSCtx.getContext()));
-    ClonedModule->setModuleIdentifier(M.getName());
+    auto ClonedModule = NewTSCtx.withContextDo([&](LLVMContext *Ctx) {
+      auto TmpM = cantFail(parseBitcodeFile(ClonedModuleBufferRef, *Ctx));
+      TmpM->setModuleIdentifier(M.getName());
+      return TmpM;
+    });
     return ThreadSafeModule(std::move(ClonedModule), std::move(NewTSCtx));
   });
 }