[llvm-c] add LLVMReplaceMDNodeOperandWith

I'm working on a tool that visits debug info and massages it using the
llvm-c API. I noticed that LLVMGetOperand special cases MDNodes so I
can get their operands, but I can't replace them. This patch adds
LLVMReplaceMDNodeOperandWith which boils down to
MDNode::replaceOperandWith.

The name was chosen for consistency with LLVMGetMDNodeOperands and
LLVMGetMDNodeNumOperands.

Differential Revision: https://reviews.llvm.org/D136637

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/IR/Core.cpp b/llvm/lib/IR/Core.cpp
index b12c483..a93fc85 100644
--- a/llvm/lib/IR/Core.cpp
+++ b/llvm/lib/IR/Core.cpp
@@ -1009,6 +1009,13 @@ LLVMValueRef LLVMIsAMDNode(LLVMValueRef Val) {
   return nullptr;
 }
 
+LLVMValueRef LLVMIsAValueAsMetadata(LLVMValueRef Val) {
+  if (auto *MD = dyn_cast_or_null<MetadataAsValue>(unwrap(Val)))
+    if (isa<ValueAsMetadata>(MD->getMetadata()))
+      return Val;
+  return nullptr;
+}
+
 LLVMValueRef LLVMIsAMDString(LLVMValueRef Val) {
   if (auto *MD = dyn_cast_or_null<MetadataAsValue>(unwrap(Val)))
     if (isa<MDString>(MD->getMetadata()))
@@ -1268,6 +1275,13 @@ void LLVMGetMDNodeOperands(LLVMValueRef V, LLVMValueRef *Dest) {
     Dest[i] = getMDNodeOperandImpl(Context, N, i);
 }
 
+void LLVMReplaceMDNodeOperandWith(LLVMValueRef V, unsigned Index,
+                                  LLVMMetadataRef Replacement) {
+  auto *MD = cast<MetadataAsValue>(unwrap(V));
+  auto *N = cast<MDNode>(MD->getMetadata());
+  N->replaceOperandWith(Index, unwrap<Metadata>(Replacement));
+}
+
 unsigned LLVMGetNamedMetadataNumOperands(LLVMModuleRef M, const char *Name) {
   if (NamedMDNode *N = unwrap(M)->getNamedMetadata(Name)) {
     return N->getNumOperands();