[clang] [CIR] Enable AppendingLinkage in GlobalLinkage enum (PR #182228)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clangir

Author: Chaitanya (skc7)

<details>
<summary>Changes</summary>

Upstreaming clangIR PR: https://github.com/llvm/clangir/pull/2098

This PR enables AppendingLinkage in CIR_GlobalLinkageKind.

---
Full diff: https://github.com/llvm/llvm-project/pull/182228.diff


4 Files Affected:

- (modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+1-2) 
- (modified) clang/include/clang/CIR/Dialect/IR/CIROpsEnums.h (+4) 
- (modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+2) 
- (added) clang/test/CIR/IR/invalid-linkage.cir (+8) 


``````````diff
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index cf312af194e85..05e3d70aebc9e 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -2345,9 +2345,8 @@ def CIR_GlobalLinkageKind : CIR_I32EnumAttr<
     I32EnumAttrCase<"WeakAnyLinkage", 4, "weak">,
     // Same, but only replaced by something equivalent.
     I32EnumAttrCase<"WeakODRLinkage", 5, "weak_odr">,
-    // TODO: should we add something like appending linkage too?
     // Special purpose, only applies to global arrays
-    // I32EnumAttrCase<"AppendingLinkage", 6, "appending">,
+    I32EnumAttrCase<"AppendingLinkage", 6, "appending">,
     // Rename collisions when linking (static functions).
     I32EnumAttrCase<"InternalLinkage", 7, "internal">,
     // Like Internal, but omit from symbol table, prefix it with
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROpsEnums.h b/clang/include/clang/CIR/Dialect/IR/CIROpsEnums.h
index dbd030446a6fc..6429ac8d5e93b 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROpsEnums.h
+++ b/clang/include/clang/CIR/Dialect/IR/CIROpsEnums.h
@@ -57,6 +57,9 @@ static bool isExternalWeakLinkage(GlobalLinkageKind linkage) {
 [[maybe_unused]] static bool isCommonLinkage(GlobalLinkageKind linkage) {
   return linkage == GlobalLinkageKind::CommonLinkage;
 }
+[[maybe_unused]] static bool isAppendingLinkage(GlobalLinkageKind linkage) {
+  return linkage == GlobalLinkageKind::AppendingLinkage;
+}
 [[maybe_unused]] static bool
 isValidDeclarationLinkage(GlobalLinkageKind linkage) {
   return isExternalWeakLinkage(linkage) || isExternalLinkage(linkage);
@@ -79,6 +82,7 @@ isValidDeclarationLinkage(GlobalLinkageKind linkage) {
     // The above three cannot be overridden but can be de-refined.
 
   case GlobalLinkageKind::ExternalLinkage:
+  case GlobalLinkageKind::AppendingLinkage:
   case GlobalLinkageKind::InternalLinkage:
   case GlobalLinkageKind::PrivateLinkage:
     return false;
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 2fd80d5e91e86..39ac686b8268e 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -152,6 +152,8 @@ mlir::LLVM::Linkage convertLinkage(cir::GlobalLinkageKind linkage) {
   using LLVM = mlir::LLVM::Linkage;
 
   switch (linkage) {
+  case CIR::AppendingLinkage:
+    return LLVM::Appending;
   case CIR::AvailableExternallyLinkage:
     return LLVM::AvailableExternally;
   case CIR::CommonLinkage:
diff --git a/clang/test/CIR/IR/invalid-linkage.cir b/clang/test/CIR/IR/invalid-linkage.cir
new file mode 100644
index 0000000000000..23771b14fcac9
--- /dev/null
+++ b/clang/test/CIR/IR/invalid-linkage.cir
@@ -0,0 +1,8 @@
+// Test that cir.global requires a valid linkage attribute
+// RUN: cir-opt %s -verify-diagnostics
+
+!u32i = !cir.int<u, 32>
+module {
+  // expected-error at +1 {{expected string or keyword containing one of the following enum values for attribute 'linkage' [external, available_externally, linkonce, linkonce_odr, weak, weak_odr, appending, internal, cir_private, extern_weak, common]}}
+  cir.global @a = #cir.const_array<[0 : !u8i, -23 : !u8i, 33 : !u8i] : !cir.array<!u32i x 3>>
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/182228