[LLVM] Add LLVMContext API to print one SyncScope ID string

Author: gonzalobg

llvm/include/llvm/IR/LLVMContext.h

@@ -130,6 +130,10 @@ class LLVMContext {
   /// scope names are ordered by increasing synchronization scope IDs.
   void getSyncScopeNames(SmallVectorImpl<StringRef> &SSNs) const;
 
+  /// getSyncScopeName - Returns the name of a SyncScope::ID
+  /// registered with LLVMContext, if any.
+  std::optional<StringRef> getSyncScopeName(SyncScope::ID Id) const;
+  
   /// Define the GC for a function
   void setGC(const Function &Fn, std::string GCName);
 

llvm/lib/IR/LLVMContext.cpp

@@ -330,6 +330,10 @@ void LLVMContext::getSyncScopeNames(SmallVectorImpl<StringRef> &SSNs) const {
   pImpl->getSyncScopeNames(SSNs);
 }
 
+std::optional<StringRef> LLVMContext::getSyncScopeName(SyncScope::ID Id) const {
+  return pImpl->getSyncScopeName(Id);
+}
+
 void LLVMContext::setGC(const Function &Fn, std::string GCName) {
   auto It = pImpl->GCNames.find(&Fn);
 

llvm/lib/IR/LLVMContextImpl.cpp

@@ -244,6 +244,14 @@ void LLVMContextImpl::getSyncScopeNames(
     SSNs[SSE.second] = SSE.first();
 }
 
+std::optional<StringRef> LLVMContextImpl::getSyncScopeName(SyncScope::ID Id) const {
+  for (const auto &SSE : SSC) {
+    if (SSE.second != Id) continue;
+    return SSE.first();
+  }
+  return std::nullopt;
+}
+
 /// Gets the OptPassGate for this LLVMContextImpl, which defaults to the
 /// singleton OptBisect if not explicitly set.
 OptPassGate &LLVMContextImpl::getOptPassGate() const {

llvm/lib/IR/LLVMContextImpl.h

@@ -1665,6 +1665,10 @@ class LLVMContextImpl {
   /// scope names are ordered by increasing synchronization scope IDs.
   void getSyncScopeNames(SmallVectorImpl<StringRef> &SSNs) const;
 
+  /// getSyncScopeName - Returns the name of a SyncScope::ID
+  /// registered with LLVMContext, if any.
+  std::optional<StringRef> getSyncScopeName(SyncScope::ID Id) const;
+  
   /// Maintain the GC name for each function.
   ///
   /// This saves allocating an additional word in Function for programs which