[PATCH] D95673: [dllimport] Honor always_inline when deciding whether a dllimport function should be available for inlining (PR48925)

[Hans Wennborg via Phabricator via cfe-commits]

hans created this revision.
hans added a reviewer: rnk.
hans requested review of this revision.
Herald added a project: clang.

Normally, Clang will not make dllimport functions available for inlining if they reference non-imported symbols, as this can lead to confusing link errors. But if the function is marked always_inline, the user presumably knows what they're doing and the attribute should be honored.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D95673

Files:
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/test/CodeGenCXX/dllimport.cpp


Index: clang/test/CodeGenCXX/dllimport.cpp
===================================================================
--- clang/test/CodeGenCXX/dllimport.cpp
+++ clang/test/CodeGenCXX/dllimport.cpp
@@ -386,6 +386,13 @@
 USE(FunctionWithTLSVar)
 USE(FunctionWithNormalVar)
 
+// always_inline and __force_inline take precedence.
+__declspec(dllimport) inline int ReferencingNonImportedFuncAlwaysInline() __attribute__((always_inline)) { return NonImportedFunc(); }
+USE(ReferencingNonImportedFuncAlwaysInline)
+// MO1-DAG: define available_externally dllimport i32 @"?ReferencingNonImportedFuncAlwaysInline@@YAHXZ"
+__declspec(dllimport) __forceinline int ReferencingNonImportedFuncForceInline() { return NonImportedFunc(); }
+USE(ReferencingNonImportedFuncForceInline)
+// MO1-DAG: define available_externally dllimport i32 @"?ReferencingNonImportedFuncForceInline@@YAHXZ"
 
 //===----------------------------------------------------------------------===//
 // Function templates
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -3031,7 +3031,7 @@
   if (CodeGenOpts.OptimizationLevel == 0 && !F->hasAttr<AlwaysInlineAttr>())
     return false;
 
-  if (F->hasAttr<DLLImportAttr>()) {
+  if (F->hasAttr<DLLImportAttr>() && !F->hasAttr<AlwaysInlineAttr>()) {
     // Check whether it would be safe to inline this dllimport function.
     DLLImportFunctionVisitor Visitor;
     Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));


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