[MLIR] Add target_specific_attrs attribute to mlir.global (#154706)

Adds a `target_specific_attrs` optional array attribute to
`mlir.global`, as well as conversions to and from LLVM attributes on
`llvm::GlobalVariable` objects. This is necessary to preserve unknown
attributes on global variables when converting to and from the LLVM
Dialect. Previously, any attributes on an `llvm::GlobalVariable` not
explicitly modeled by `mlir.global` were dropped during conversion.

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index d1fbcb9..4ac2ebd 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -954,6 +954,19 @@ AttributeSet AttributeSet::addAttributes(LLVMContext &C,
   return get(C, B);
 }
 
+AttributeSet AttributeSet::addAttributes(LLVMContext &C,
+                                         const AttrBuilder &B) const {
+  if (!hasAttributes())
+    return get(C, B);
+
+  if (!B.hasAttributes())
+    return *this;
+
+  AttrBuilder Merged(C, *this);
+  Merged.merge(B);
+  return get(C, Merged);
+}
+
 AttributeSet AttributeSet::removeAttribute(LLVMContext &C,
                                              Attribute::AttrKind Kind) const {
   if (!hasAttribute(Kind)) return *this;