[FMV] Emit the resolver along with the default version definition. (#84405)

We would like the resolver to be generated eagerly, even if the
versioned function is not called from the current translation
unit. Fixes #81494. It further allows Multi Versioning to work
even if the default target version attribute is omitted from
function declarations.

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index ec34680f..1cc4477 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -348,6 +348,8 @@ private:
   /// yet.
   llvm::DenseMap<StringRef, GlobalDecl> DeferredDecls;
 
+  llvm::StringSet<llvm::BumpPtrAllocator> DeferredResolversToEmit;
+
   /// This is a list of deferred decls which we have seen that *are* actually
   /// referenced. These get code generated when the module is done.
   std::vector<GlobalDecl> DeferredDeclsToEmit;
@@ -1588,6 +1590,9 @@ private:
       llvm::AttributeList ExtraAttrs = llvm::AttributeList(),
       ForDefinition_t IsForDefinition = NotForDefinition);
 
+  // Adds a declaration to the list of multi version functions if not present.
+  void AddDeferredMultiVersionResolverToEmit(GlobalDecl GD);
+
   // References to multiversion functions are resolved through an implicitly
   // defined resolver function. This function is responsible for creating
   // the resolver symbol for the provided declaration. The value returned