[clang] [clang-tools-extra] [clang] Hide the `TargetOptions` pointer from `CompilerInvocation` (PR #106271)

[kadir çetinkaya via cfe-commits]

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@@ -216,7 +216,7 @@ enum OpenCLTypeKind : uint8_t {
 ///
 class TargetInfo : public TransferrableTargetInfo,
                    public RefCountedBase<TargetInfo> {
-  std::shared_ptr<TargetOptions> TargetOpts;
+  TargetOptions *TargetOpts;
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kadircet wrote:

this is making me a little anxious. previously a `TargetInfo` was valid even if `TargetOptions` used during construction went away.

now we're breaking that contract, any code pattern that keeps `TargetInfo`s alive, now needs to make sure underlying options are outliving it. AFAICT, you ensured usages upstream are updated accordingly (and are safe), but I am afraid this might break downstream projects. This is fine, but it would be nice to prevent it if we can.

I do understand we need to hide `TargetOptions` from `CompilerInvocation`, but do we have a reason to make this reference non-owning ? (this should also ensure we don't create a new unique_ptr for AuxTargetOpts in `CompilerInstance.h`.

https://github.com/llvm/llvm-project/pull/106271