[clang] [clang-repl] Keep earlier declarations alive when an input fails (PR #218149)

[Vassil Vassilev via cfe-commits]

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@@ -120,6 +120,8 @@ std::unique_ptr<llvm::Module> IncrementalAction::GenModule() {
   return nullptr;
 }
 
+void IncrementalAction::discardModule() { GenModule(); }
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vgvassilev wrote:

I also think this is suboptimal -- we are forcing a module to be removed but that's only the last module. What happens if we are undoing a past module? Also we need to free the machine code produced by the jit...

https://github.com/llvm/llvm-project/pull/218149