[llvm] [llvm][IR] Add per-global code model attribute (PR #72077)

[Arthur Eubanks via llvm-commits]

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@@ -124,6 +126,24 @@ class GlobalObject : public GlobalValue {
   /// appropriate default object file section.
   void setSection(StringRef S);
 
+  /// Check if this global has a custom code model.
+  ///
+  bool hasCodeModel() const {
+    return getGlobalValueSubClassData() & (1 << HasCodeModelHashEntryBit);
+  }
+
+  /// Get the custom code model of this global if it has one.
+  ///
+  /// If this global does not have a custom code model, the default small code
+  /// model will be used.
+  CodeModel::Model getCodeModel() const {
+    return hasCodeModel() ? getCodeModelImpl() : CodeModel::Small;
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aeubanks wrote:

we shouldn't assume a default code model, this should return a std::optional

https://github.com/llvm/llvm-project/pull/72077