[NFC][IR] Add SetNoSanitize helpers (#86772)

This will be used by #86775

Author: vitalybuka

llvm/include/llvm/IR/GlobalValue.h

@@ -360,6 +360,7 @@ class GlobalValue : public Constant {
   // storage is shared between `G1` and `G2`.
   void setSanitizerMetadata(SanitizerMetadata Meta);
   void removeSanitizerMetadata();
+  void setNoSanitizeMetadata();
 
   bool isTagged() const {
     return hasSanitizerMetadata() && getSanitizerMetadata().Memtag;

llvm/include/llvm/IR/IRBuilder.h

@@ -221,6 +221,12 @@ class IRBuilderBase {
     AddOrRemoveMetadataToCopy(LLVMContext::MD_dbg, L.getAsMDNode());
   }
 
+  /// Set nosanitize metadata.
+  void SetNoSanitizeMetadata() {
+    AddOrRemoveMetadataToCopy(llvm::LLVMContext::MD_nosanitize,
+                              llvm::MDNode::get(getContext(), std::nullopt));
+  }
+
   /// Collect metadata with IDs \p MetadataKinds from \p Src which should be
   /// added to all created instructions. Entries present in MedataDataToCopy but
   /// not on \p Src will be dropped from MetadataToCopy.

llvm/lib/IR/Globals.cpp

@@ -243,6 +243,13 @@ void GlobalValue::removeSanitizerMetadata() {
   HasSanitizerMetadata = false;
 }
 
+void GlobalValue::setNoSanitizeMetadata() {
+  SanitizerMetadata Meta;
+  Meta.NoAddress = true;
+  Meta.NoHWAddress = true;
+  setSanitizerMetadata(Meta);
+}
+
 StringRef GlobalObject::getSectionImpl() const {
   assert(hasSection());
   return getContext().pImpl->GlobalObjectSections[this];