From a831ce528fc0fd16734d644e62ae956834276c1b Mon Sep 17 00:00:00 2001
From: Shoaib Meenai <smeenai@fb.com>
Date: Thu, 26 May 2022 09:34:18 -0700
Subject: [PATCH] Revert "[runtimes] Detect changes to Tests.cmake"

This reverts commit ec10ac750a8ad96983d85263323635f3dabe92fd.

See https://discourse.llvm.org/t/cmake-regeneration-is-broken/62788.
This change caused Ninja's CMake regeneration to depend on the build,
which prevented CMake regeneration from functioning properly and caused
spurious build failures on incremental builds when a CMake change
occurred.
---
 .../modules/LLVMExternalProjectUtils.cmake    |  5 +----
 llvm/runtimes/CMakeLists.txt                  | 22 ++++++++++---------
 2 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/llvm/cmake/modules/LLVMExternalProjectUtils.cmake b/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
index cf0f18476b60..f99a50df2280 100644
--- a/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
+++ b/llvm/cmake/modules/LLVMExternalProjectUtils.cmake
@@ -56,14 +56,12 @@ endfunction()
 #     Use provided strip tool instead of the default one.
 #   TARGET_TRIPLE triple
 #     Optional target triple to pass to the compiler
-#   BYPRODUCTS files...
-#     Files generated as a byproduct of this build.
 #   )
 function(llvm_ExternalProject_Add name source_dir)
   cmake_parse_arguments(ARG
     "USE_TOOLCHAIN;EXCLUDE_FROM_ALL;NO_INSTALL;ALWAYS_CLEAN"
     "SOURCE_DIR"
-    "CMAKE_ARGS;TOOLCHAIN_TOOLS;RUNTIME_LIBRARIES;DEPENDS;EXTRA_TARGETS;PASSTHROUGH_PREFIXES;STRIP_TOOL;TARGET_TRIPLE;BYPRODUCTS"
+    "CMAKE_ARGS;TOOLCHAIN_TOOLS;RUNTIME_LIBRARIES;DEPENDS;EXTRA_TARGETS;PASSTHROUGH_PREFIXES;STRIP_TOOL;TARGET_TRIPLE"
     ${ARGN})
   canonicalize_tool_name(${name} nameCanon)
 
@@ -324,7 +322,6 @@ function(llvm_ExternalProject_Add name source_dir)
     INSTALL_COMMAND ""
     STEP_TARGETS configure build
     BUILD_ALWAYS 1
-    BUILD_BYPRODUCTS ${ARG_BYPRODUCTS}
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     USES_TERMINAL_INSTALL 1
diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
index 836e9149a71f..34fcccab100c 100644
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -219,11 +219,13 @@ function(runtime_default_target)
   endforeach()
 
   if(LLVM_INCLUDE_TESTS)
-    include(${LLVM_BINARY_DIR}/runtimes/Tests.cmake OPTIONAL)
+    include(${LLVM_BINARY_DIR}/runtimes/Tests.cmake OPTIONAL RESULT_VARIABLE have_tests)
     set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/Tests.cmake)
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_TESTSUITES ${SUB_LIT_TESTSUITES})
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_PARAMS ${SUB_LIT_PARAMS})
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_EXTRA_ARGS ${SUB_LIT_EXTRA_ARGS})
+    if(have_tests)
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_TESTSUITES ${SUB_LIT_TESTSUITES})
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_PARAMS ${SUB_LIT_PARAMS})
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_EXTRA_ARGS ${SUB_LIT_EXTRA_ARGS})
+    endif()
     list(APPEND test_targets runtimes-test-depends check-runtimes)
   endif()
 
@@ -258,7 +260,6 @@ function(runtime_default_target)
                                          ${SUB_INSTALL_TARGETS}
                            USE_TOOLCHAIN
                            TARGET_TRIPLE ${LLVM_TARGET_TRIPLE}
-                           BYPRODUCTS ${LLVM_BINARY_DIR}/runtimes/Tests.cmake
                            ${EXTRA_ARGS})
 endfunction()
 
@@ -300,11 +301,13 @@ function(runtime_register_target name target)
   endforeach()
 
   if(LLVM_INCLUDE_TESTS)
-    include(${LLVM_BINARY_DIR}/runtimes/${name}/Tests.cmake OPTIONAL)
+    include(${LLVM_BINARY_DIR}/runtimes/${name}/Tests.cmake OPTIONAL RESULT_VARIABLE have_tests)
     set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${LLVM_BINARY_DIR}/runtimes/${name}/Tests.cmake)
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_TESTSUITES ${SUB_LIT_TESTSUITES})
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_PARAMS ${SUB_LIT_PARAMS})
-    set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_EXTRA_ARGS ${SUB_LIT_EXTRA_ARGS})
+    if(have_tests)
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_TESTSUITES ${SUB_LIT_TESTSUITES})
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_PARAMS ${SUB_LIT_PARAMS})
+      set_property(GLOBAL APPEND PROPERTY LLVM_ALL_LIT_EXTRA_ARGS ${SUB_LIT_EXTRA_ARGS})
+    endif()
     set(runtimes-test-depends-${name} runtimes-test-depends)
     set(check-runtimes-${name} check-runtimes)
     list(APPEND ${name}_test_targets runtimes-test-depends-${name} check-runtimes-${name})
@@ -364,7 +367,6 @@ function(runtime_register_target name target)
                                          ${${name}_test_targets}
                            USE_TOOLCHAIN
                            TARGET_TRIPLE ${target}
-                           BYPRODUCTS ${LLVM_BINARY_DIR}/runtimes/${name}/Tests.cmake
                            ${EXTRA_ARGS})
 endfunction()