[clang] Hide the `TargetOptions` pointer from `CompilerInvocation` (#106271)

This PR hides the reference-counted pointer that holds `TargetOptions`
from the public API of `CompilerInvocation`. This gives
`CompilerInvocation` an exclusive control over the lifetime of this
member, which will eventually be leveraged to implement a copy-on-write
behavior.

There are two clients that currently share ownership of that pointer:

* `TargetInfo` - This was refactored to hold a non-owning reference to
`TargetOptions`. The options object is typically owned by the
`CompilerInvocation` or by the new `CompilerInstance::AuxTargetOpts` for
the auxiliary target. This needed a bit of care in `ASTUnit::Parse()` to
keep the `CompilerInvocation` alive.
* `clangd::PreambleData` - This was refactored to exclusively own the
`TargetOptions` that get moved out of the `CompilerInvocation`.

1 files changed, 3 insertions, 3 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 1526ea5..2d6ab87 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -110,7 +110,7 @@ void CompilerInstance::setAuxTarget(TargetInfo *Value) { AuxTarget = Value; }
 bool CompilerInstance::createTarget() {
   // Create the target instance.
   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
-                                         getInvocation().TargetOpts));
+                                         getInvocation().getTargetOpts()));
   if (!hasTarget())
     return false;
 
@@ -119,14 +119,14 @@ bool CompilerInstance::createTarget() {
   if (!getAuxTarget() &&
       (getLangOpts().CUDA || getLangOpts().isTargetDevice()) &&
       !getFrontendOpts().AuxTriple.empty()) {
-    auto TO = std::make_shared<TargetOptions>();
+    auto &TO = AuxTargetOpts = std::make_unique<TargetOptions>();
     TO->Triple = llvm::Triple::normalize(getFrontendOpts().AuxTriple);
     if (getFrontendOpts().AuxTargetCPU)
       TO->CPU = *getFrontendOpts().AuxTargetCPU;
     if (getFrontendOpts().AuxTargetFeatures)
       TO->FeaturesAsWritten = *getFrontendOpts().AuxTargetFeatures;
     TO->HostTriple = getTarget().getTriple().str();
-    setAuxTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), TO));
+    setAuxTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), *TO));
   }
 
   if (!getTarget().hasStrictFP() && !getLangOpts().ExpStrictFP) {