1 files changed, 26 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 5646099015b..99d4a79c466 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9828,6 +9828,16 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
     FinalizeVarWithDestructor(var, recordType);
 }
 
+/// \brief Determines if a variable's alignment is dependent.
+static bool hasDependentAlignment(VarDecl *VD) {
+  if (VD->getType()->isDependentType())
+    return true;
+  for (auto *I : VD->specific_attrs<AlignedAttr>())
+    if (I->isAlignmentDependent())
+      return true;
+  return false;
+}
+
 /// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
 /// any semantic actions necessary after any initializer has been attached.
 void
@@ -9841,6 +9851,22 @@ Sema::FinalizeDeclaration(Decl *ThisDecl) {
 
   checkAttributesAfterMerging(*this, *VD);
 
+  // Perform TLS alignment check here after attributes attached to the variable
+  // which may affect the alignment have been processed. Only perform the check
+  // if the target has a maximum TLS alignment (zero means no constraints).
+  if (unsigned MaxAlign = Context.getTargetInfo().getMaxTLSAlign()) {
+    // Protect the check so that it's not performed on dependent types and
+    // dependent alignments (we can't determine the alignment in that case).
+    if (VD->getTLSKind() && !hasDependentAlignment(VD)) {
+      CharUnits MaxAlignChars = Context.toCharUnitsFromBits(MaxAlign);
+      if (Context.getDeclAlign(VD) > MaxAlignChars) {
+        Diag(VD->getLocation(), diag::err_tls_var_aligned_over_maximum)
+          << (unsigned)Context.getDeclAlign(VD).getQuantity() << VD
+          << (unsigned)MaxAlignChars.getQuantity();
+      }
+    }
+  }
+
   // Static locals inherit dll attributes from their function.
   if (VD->isStaticLocal()) {
     if (FunctionDecl *FD =