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

[Eli Friedman via cfe-commits]

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@@ -265,6 +269,63 @@ bool AIXTargetCodeGenInfo::initDwarfEHRegSizeTable(
   return PPC_initDwarfEHRegSizeTable(CGF, Address, Is64Bit, /*IsAIX*/ true);
 }
 
+void AIXTargetCodeGenInfo::setTargetAttributes(
+    const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const {
+  if (auto *GVar = dyn_cast<llvm::GlobalVariable>(GV)) {
+    auto GVId = M.getMangledName(dyn_cast<NamedDecl>(D));
+
+    // Is this a global variable specified by the user as toc-data?
+    bool UserSpecifiedTOC =
+        llvm::binary_search(M.getCodeGenOpts().TocDataVarsUserSpecified, GVId);
+    // Assumes the same variable cannot be in both TocVarsUserSpecified and
+    // NoTocVars.
+    if (UserSpecifiedTOC ||
+        ((M.getCodeGenOpts().AllTocData) &&
+         !llvm::binary_search(M.getCodeGenOpts().NoTocDataVars, GVId))) {
+      const unsigned long PointerSize =
+          GV->getParent()->getDataLayout().getPointerSizeInBits() / 8;
+      ASTContext &Context = D->getASTContext();
+      auto *VarD = dyn_cast<VarDecl>(D);
+      assert(VarD && "Invalid declaration of global variable.");
+
+      unsigned Alignment = Context.toBits(Context.getDeclAlign(D)) / 8;
+      const auto *Ty = VarD->getType().getTypePtr();
+      const RecordDecl *RDecl =
+          Ty->isRecordType() ? Ty->getAs<RecordType>()->getDecl() : nullptr;
+
+      bool EmitDiagnostic = UserSpecifiedTOC && GV->hasExternalLinkage();
+      if (!Ty || Ty->isIncompleteType()) {
+        if (EmitDiagnostic)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "of incomplete type";
+      } else if (RDecl && RDecl->hasFlexibleArrayMember()) {
+        if (UserSpecifiedTOC)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "it contains a flexible array member";
+      } else if (VarD->getTLSKind() != VarDecl::TLS_None) {
+        if (EmitDiagnostic)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "of thread local storage model";
+      } else if (PointerSize < Context.getTypeInfo(VarD->getType()).Width / 8) {
+        if (EmitDiagnostic)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "variable is larger than a pointer";
+      } else if (PointerSize < Alignment) {
+        if (EmitDiagnostic)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "variable is aligned wider than a pointer";
+      } else if (D->hasAttr<SectionAttr>()) {
+        if (EmitDiagnostic)
+          M.getDiags().Report(D->getLocation(), diag::warn_toc_unsupported_type)
+              << GVId << "of a section attribute";
+      } else if ((GV->hasExternalLinkage() || M.getCodeGenOpts().AllTocData) &&
+                 !GV->hasInternalLinkage()) {
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efriedma-quic wrote:

Maybe should be `hasLocalLinkage()`?

https://github.com/llvm/llvm-project/pull/67999