[clang] [CIR][X86] Implement lowering for `_AddressOfReturnAddress` builtin (PR #171974)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Haocong Lu (Luhaocong)

<details>
<summary>Changes</summary>

Part of https://github.com/llvm/llvm-project/issues/167765

---
Full diff: https://github.com/llvm/llvm-project/pull/171974.diff


2 Files Affected:

- (modified) clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp (+6-1) 
- (added) clang/test/CIR/CodeGen/ms-intrinsics.c (+40) 


``````````diff
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
index f9e1f75a51143..5b6e0537c32d1 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
@@ -1706,7 +1706,12 @@ CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID, const CallExpr *expr) {
                                     cir::SyncScopeKind::SingleThread));
     return mlir::Value{};
   }
-  case X86::BI_AddressOfReturnAddress:
+  case X86::BI_AddressOfReturnAddress: {
+    mlir::Location loc = getLoc(expr->getExprLoc());
+    mlir::Value addr = emitIntrinsicCallOp(
+        builder, loc, "addressofreturnaddress", allocaInt8PtrTy);
+    return builder.createCast(loc, cir::CastKind::bitcast, addr, voidPtrTy);
+  }
   case X86::BI__stosb:
   case X86::BI__ud2:
   case X86::BI__int2c:
diff --git a/clang/test/CIR/CodeGen/ms-intrinsics.c b/clang/test/CIR/CodeGen/ms-intrinsics.c
new file mode 100644
index 0000000000000..0d07db2beac46
--- /dev/null
+++ b/clang/test/CIR/CodeGen/ms-intrinsics.c
@@ -0,0 +1,40 @@
+// RUN: %clang_cc1 -x c -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -Wno-implicit-function-declaration -fclangir -emit-cir -o %t.cir %s
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -x c++ -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -Wno-implicit-function-declaration -fclangir -emit-cir -o %t.cir %s
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+
+// RUN: %clang_cc1 -x c -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -Wno-implicit-function-declaration -fclangir -emit-llvm -o %t.ll %s
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t.ll %s
+// RUN: %clang_cc1 -x c++ -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -Wno-implicit-function-declaration -fclangir -emit-llvm -o %t.ll %s
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t.ll %s
+
+// RUN: %clang_cc1 -x c -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -emit-llvm -Wall -Werror %s -o - \
+// RUN:   | FileCheck %s -check-prefix=OGCG
+// RUN: %clang_cc1 -x c++ -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
+// RUN:   -triple x86_64-unknown-linux -emit-llvm -Wall -Werror %s -o - \
+// RUN:   | FileCheck %s -check-prefix=OGCG
+
+// This test mimics clang/test/CodeGen/ms-intrinsics.c, which eventually
+// CIR shall be able to support fully.
+
+void *_AddressOfReturnAddress(void);
+
+#if defined(__i386__) || defined(__x86_64__) || defined (__aarch64__)
+void *test_AddressOfReturnAddress(void) {
+  // CIR-LABEL: test_AddressOfReturnAddress
+  // CIR: %[[ADDR:.*]] = cir.call_llvm_intrinsic "addressofreturnaddress" : () -> !cir.ptr<!u8i>
+  // CIR: %{{.*}} = cir.cast bitcast %[[ADDR]] : !cir.ptr<!u8i> -> !cir.ptr<!void>
+
+  // LLVM-LABEL: test_AddressOfReturnAddress
+  // LLVM: call ptr @llvm.addressofreturnaddress.p0()
+
+  // OGCG-LABEL: test_AddressOfReturnAddress
+  // OGCG: call ptr @llvm.addressofreturnaddress.p0()
+  return _AddressOfReturnAddress();
+}
+#endif

``````````

</details>


https://github.com/llvm/llvm-project/pull/171974