[llvm] Use LLVM_DEFAULT_TARGET_TRIPLE to find target libs (PR #72498)

[Omair Javaid via llvm-commits]

https://github.com/omjavaid created https://github.com/llvm/llvm-project/pull/72498

find_compiler_rt_library uses CMAKE_CXX_COMPILER_TARGET to find target triple in case it is not supplied as an argument. However in some situations CMAKE_CXX_COMPILER_TARGET may not be set and this patch allows usage of LLVM_DEFAULT_TARGET_TRIPLE for finding compiler rt libs.

>From d20016dfccc91f5657479b82f8c07fd33449370d Mon Sep 17 00:00:00 2001
From: Muhammad Omair Javaid <omair.javaid at linaro.org>
Date: Thu, 16 Nov 2023 14:46:29 +0500
Subject: [PATCH] Use LLVM_DEFAULT_TARGET_TRIPLE to find target libs

find_compiler_rt_library uses CMAKE_CXX_COMPILER_TARGET to find target
triple in case it is not supplied as an argument. However in some situations
CMAKE_CXX_COMPILER_TARGET may not be set and this patch allows usage of
LLVM_DEFAULT_TARGET_TRIPLE for finding compiler rt libs.
---
 cmake/Modules/HandleCompilerRT.cmake | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cmake/Modules/HandleCompilerRT.cmake b/cmake/Modules/HandleCompilerRT.cmake
index 6865f45175ed797..70d39acb27f98e8 100644
--- a/cmake/Modules/HandleCompilerRT.cmake
+++ b/cmake/Modules/HandleCompilerRT.cmake
@@ -61,6 +61,8 @@ function(find_compiler_rt_library name variable)
   set(target "${ARG_TARGET}")
   if(NOT target AND CMAKE_CXX_COMPILER_TARGET)
     set(target "${CMAKE_CXX_COMPILER_TARGET}")
+  elseif(LLVM_DEFAULT_TARGET_TRIPLE)
+    set(target "${LLVM_DEFAULT_TARGET_TRIPLE}")
   endif()
   if(NOT DEFINED COMPILER_RT_LIBRARY_builtins_${target})
     # If the cache variable is not defined, invoke Clang and then