[clang] [CIR] Upstream missing support for vtables and virtual bases (PR #192617)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Elio (xiongzile)

<details>
<summary>Changes</summary>

Refer: https://github.com/llvm/llvm-project/issues/192330

---
Full diff: https://github.com/llvm/llvm-project/pull/192617.diff


1 Files Affected:

- (modified) clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp (+3-2) 


``````````diff
diff --git a/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp b/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
index 75658b23790bf..edfaea83c1a7f 100644
--- a/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
@@ -2069,8 +2069,9 @@ mlir::Value CIRGenItaniumCXXABI::getVirtualBaseClassOffset(
 
   mlir::Value vbaseOffset;
   if (cgm.getLangOpts().RelativeCXXABIVTables) {
-    assert(!cir::MissingFeatures::vtableRelativeLayout());
-    cgm.errorNYI(loc, "getVirtualBaseClassOffset: relative layout");
+    vbaseOffset = cgf.getBuilder().createLoad(
+        loc, Address(vbaseOffsetPtr, cgm.sInt32Ty,
+                     CharUnits::fromQuantity(4))); // vbase.offset
   } else {
     mlir::Value offsetPtr = builder.createBitcast(
         vbaseOffsetPtr, builder.getPointerTo(cgm.ptrDiffTy));

``````````

</details>


https://github.com/llvm/llvm-project/pull/192617