[AIX][TOC] Add -mtocdata/-mno-tocdata options on AIX (#67999)

This patch enables support that the XL compiler had for AIX under
-qdatalocal/-qdataimported.

1 files changed, 26 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 967319b..8ceecff 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -626,6 +626,26 @@ static bool checkAliasedGlobal(
   return true;
 }
 
+// Emit a warning if toc-data attribute is requested for global variables that
+// have aliases and remove the toc-data attribute.
+static void checkAliasForTocData(llvm::GlobalVariable *GVar,
+                                 const CodeGenOptions &CodeGenOpts,
+                                 DiagnosticsEngine &Diags,
+                                 SourceLocation Location) {
+  if (GVar->hasAttribute("toc-data")) {
+    auto GVId = GVar->getName();
+    // Is this a global variable specified by the user as local?
+    if ((llvm::binary_search(CodeGenOpts.TocDataVarsUserSpecified, GVId))) {
+      Diags.Report(Location, diag::warn_toc_unsupported_type)
+          << GVId << "the variable has an alias";
+    }
+    llvm::AttributeSet CurrAttributes = GVar->getAttributes();
+    llvm::AttributeSet NewAttributes =
+        CurrAttributes.removeAttribute(GVar->getContext(), "toc-data");
+    GVar->setAttributes(NewAttributes);
+  }
+}
+
 void CodeGenModule::checkAliases() {
   // Check if the constructed aliases are well formed. It is really unfortunate
   // that we have to do this in CodeGen, but we only construct mangled names
@@ -652,6 +672,12 @@ void CodeGenModule::checkAliases() {
       continue;
     }
 
+    if (getContext().getTargetInfo().getTriple().isOSAIX())
+      if (const llvm::GlobalVariable *GVar =
+              dyn_cast<const llvm::GlobalVariable>(GV))
+        checkAliasForTocData(const_cast<llvm::GlobalVariable *>(GVar),
+                             getCodeGenOpts(), Diags, Location);
+
     llvm::Constant *Aliasee =
         IsIFunc ? cast<llvm::GlobalIFunc>(Alias)->getResolver()
                 : cast<llvm::GlobalAlias>(Alias)->getAliasee();