[clang] Set correct CXXABI for UEFI (llvm#150115)

The target triple x86_64-uefi must be assumed to have Microsft ABI by
default.

Fixes: llvm#150113

Author: Prabhuk

clang/lib/Basic/TargetInfo.cpp

@@ -172,7 +172,7 @@ TargetInfo::TargetInfo(const llvm::Triple &T) : Triple(T) {
   ComplexLongDoubleUsesFP2Ret = false;
 
   // Set the C++ ABI based on the triple.
-  TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment()
+  TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment() || Triple.isUEFI()
                     ? TargetCXXABI::Microsoft
                     : TargetCXXABI::GenericItanium);
 

clang/test/Layout/ms-no-unique-address.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -std=c++2a -fsyntax-only -triple x86_64-windows-msvc -fms-compatibility -fdump-record-layouts %s | FileCheck %s
+// RUN: %clang_cc1 -std=c++2a -fsyntax-only -triple x86_64-uefi -fms-compatibility -fdump-record-layouts %s | FileCheck %s
 
 namespace Empty {
   struct A {};

clang/test/SemaCXX/cxx2a-ms-no-unique-address.cpp

@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -std=c++2a %s -verify=unsupported -triple x86_64-linux-gnu
 // RUN: %clang_cc1 -std=c++2a %s -verify -triple x86_64-windows -fms-compatibility
+// RUN: %clang_cc1 -std=c++2a %s -verify -triple x86_64-uefi -fms-compatibility
 
 [[msvc::no_unique_address]] int a; // expected-error {{only applies to non-bit-field non-static data members}} unsupported-warning {{unknown}}
 [[msvc::no_unique_address]] void f(); // expected-error {{only applies to non-bit-field non-static data members}} unsupported-warning {{unknown}}