[llvm] Revert "[CMake][LIT] Add option to run lit testsuites in parallel" (PR #84813)

[Jeff Niu via llvm-commits]

https://github.com/Mogball created https://github.com/llvm/llvm-project/pull/84813

Reverts llvm/llvm-project#82899

Per the discussion on the PR, this needs more design and justification.

>From 7cc43fe37282c8bdf4b1d3de60faa3597c6bcbaa Mon Sep 17 00:00:00 2001
From: Jeff Niu <jeff at modular.com>
Date: Mon, 11 Mar 2024 11:43:54 -0700
Subject: [PATCH] Revert "[CMake][LIT] Add option to run lit testsuites in
 parallel (#82899)"

This reverts commit 782147e82ab3e2d0e22f729ea4e54eeed7b3cb96.
---
 llvm/CMakeLists.txt              |  2 --
 llvm/cmake/modules/AddLLVM.cmake | 17 +++++------------
 llvm/docs/CMake.rst              |  6 ------
 3 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index d9a17a869acfa0..bd141619d03fd1 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -712,8 +712,6 @@ if(LLVM_INDIVIDUAL_TEST_COVERAGE)
 endif()
 set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
 
-option(LLVM_PARALLEL_LIT "Enable multiple lit suites to run in parallel" OFF)
-
 # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
 if( WIN32 AND NOT CYGWIN )
   set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 828de4bd9940d6..374f5e085d9118 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1947,18 +1947,11 @@ function(add_lit_target target comment)
     list(APPEND LIT_COMMAND --param ${param})
   endforeach()
   if (ARG_UNPARSED_ARGUMENTS)
-    if (LLVM_PARALLEL_LIT)
-     add_custom_target(${target}
-       COMMAND ${LIT_COMMAND} ${ARG_UNPARSED_ARGUMENTS}
-       COMMENT "${comment}"
-       )
-    else()
-     add_custom_target(${target}
-       COMMAND ${LIT_COMMAND} ${ARG_UNPARSED_ARGUMENTS}
-       COMMENT "${comment}"
-       USES_TERMINAL
-       )
-    endif()
+    add_custom_target(${target}
+      COMMAND ${LIT_COMMAND} ${ARG_UNPARSED_ARGUMENTS}
+      COMMENT "${comment}"
+      USES_TERMINAL
+      )
   else()
     add_custom_target(${target}
       COMMAND ${CMAKE_COMMAND} -E echo "${target} does nothing, no tools built.")
diff --git a/llvm/docs/CMake.rst b/llvm/docs/CMake.rst
index be5da5652e31e3..1490b38feb1eb5 100644
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@@ -762,12 +762,6 @@ enabled sub-projects. Nearly all of these variable names begin with
 **LLVM_PARALLEL_LINK_JOBS**:STRING
   Define the maximum number of concurrent link jobs.
 
-**LLVM_PARALLEL_LIT**:BOOL
-  Defaults to ``OFF``. If set to ``OFF``, lit testsuites will be configured
-  with CMake's ``USES_TERMINAL`` flag to give direct access to the terminal. If
-  set to ``ON``, that flag will be removed allowing Ninja to schedule multiple
-  lit testsuites in parallel.
-
 **LLVM_RAM_PER_COMPILE_JOB**:STRING
   Calculates the amount of Ninja compile jobs according to available resources.
   Value has to be in MB, overwrites LLVM_PARALLEL_COMPILE_JOBS. Compile jobs