DI: Add Function::getSubprogram()

Add `Function::setSubprogram()` and `Function::getSubprogram()`,
convenience methods to forward to `setMetadata()` and `getMetadata()`,
respectively, and deal in `DISubprogram` instead of `MDNode`.

Also add a verifier check to enforce that `!dbg` attachments are always
subprograms.

Originally (when I had the llvm-dev discussion back in April) I thought
I'd store a pointer directly on `llvm::Function` for these attachments
-- we frequently have debug info, and that's much cheaper than using map
in the context if there are no other function-level attachments -- but
for now I'm just using the generic infrastructure.  Let's add the extra
complexity only if this shows up in a profile.

llvm-svn: 246339

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index 431fee1b7b7..7d8c3523743 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -1259,3 +1259,11 @@ void Function::clearMetadata() {
   getContext().pImpl->FunctionMetadata.erase(this);
   setHasMetadataHashEntry(false);
 }
+
+void Function::setSubprogram(DISubprogram *SP) {
+  setMetadata(LLVMContext::MD_dbg, SP);
+}
+
+DISubprogram *Function::getSubprogram() const {
+  return cast_or_null<DISubprogram>(getMetadata(LLVMContext::MD_dbg));
+}