[llvm] [CI] Disable precompiled headers in monolithic-*.sh (PR #143369)

[Kajetan Puchalski via llvm-commits]

https://github.com/mrkajetanp created https://github.com/llvm/llvm-project/pull/143369

Using precompiled headers can result in code with missing explicit includes building correctly because the headers will be already included through the pch. If code like this is committed, however, then trying to build the project with precompiled headers disabled will cause build errors.

Disable precompiled headers in pre-merge CI scripts to make sure these issues are caught early.

Resolves https://github.com/llvm/llvm-project/issues/143234.

>From 5d1a87c7db62f52a0d3fbc5a7db70c70710c9181 Mon Sep 17 00:00:00 2001
From: Kajetan Puchalski <kajetan.puchalski at arm.com>
Date: Mon, 9 Jun 2025 11:18:17 +0000
Subject: [PATCH] [CI] Disable precompiled headers in monolithic-*.sh

Using precompiled headers can result in code with missing explicit
includes building correctly because the headers will be already included
through the pch. If code like this is committed, however, then trying to
build the project with precompiled headers disabled will cause build
errors.

Disable precompiled headers in pre-merge CI scripts to make sure these
issues are caught early.

Signed-off-by: Kajetan Puchalski <kajetan.puchalski at arm.com>
---
 .ci/monolithic-linux.sh   | 1 +
 .ci/monolithic-windows.sh | 1 +
 2 files changed, 2 insertions(+)

diff --git a/.ci/monolithic-linux.sh b/.ci/monolithic-linux.sh
index 52a80958b4025..d0b553cc6d865 100755
--- a/.ci/monolithic-linux.sh
+++ b/.ci/monolithic-linux.sh
@@ -81,6 +81,7 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D LLVM_ENABLE_LLD=ON \
       -D CMAKE_CXX_FLAGS=-gmlt \
       -D LLVM_CCACHE_BUILD=ON \
+      -D CMAKE_DISABLE_PRECOMPILE_HEADERS=ON \
       -D LIBCXX_CXX_ABI=libcxxabi \
       -D MLIR_ENABLE_BINDINGS_PYTHON=ON \
       -D LLDB_ENABLE_PYTHON=ON \
diff --git a/.ci/monolithic-windows.sh b/.ci/monolithic-windows.sh
index a0997420b0d3f..8c83885e4bea9 100755
--- a/.ci/monolithic-windows.sh
+++ b/.ci/monolithic-windows.sh
@@ -76,6 +76,7 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D COMPILER_RT_BUILD_ORC=OFF \
       -D CMAKE_C_COMPILER_LAUNCHER=sccache \
       -D CMAKE_CXX_COMPILER_LAUNCHER=sccache \
+      -D CMAKE_DISABLE_PRECOMPILE_HEADERS=ON \
       -D MLIR_ENABLE_BINDINGS_PYTHON=ON \
       -D CMAKE_EXE_LINKER_FLAGS="/MANIFEST:NO" \
       -D CMAKE_MODULE_LINKER_FLAGS="/MANIFEST:NO" \