From 5b3d4fc91d9f2152199fb9173e948b7612d84fc7 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Wed, 30 Jul 2025 17:04:06 -0700
Subject: [PATCH] Put PCH behind a cmake flag

Allows developers to turn it off if they don't like/don't want it
---
 CMakeLists.txt           |  4 +++
 common/CMakeLists.txt    | 76 ++++++++++++++++++++++------------------
 common/build_version.cpp |  7 ++++
 eeschema/CMakeLists.txt  | 24 +++++++------
 pcbnew/CMakeLists.txt    |  2 +-
 5 files changed, 66 insertions(+), 47 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7720645811..97d3097cb9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -233,6 +233,10 @@ cmake_dependent_option( KICAD_WIN32_LTCG
     OFF "WIN32"
     OFF )
 
+option( KICAD_USE_PCH
+    "Enable precompiled header support"
+    ON )
+
 # Advanced option to make link maps (only available on linux)
 cmake_dependent_option( KICAD_MAKE_LINK_MAPS
     "Create link maps for artifacts"
diff --git a/common/CMakeLists.txt b/common/CMakeLists.txt
index 92d278086a..153afcffc1 100644
--- a/common/CMakeLists.txt
+++ b/common/CMakeLists.txt
@@ -239,18 +239,20 @@ add_library( kicommon SHARED
     ${KICOMMON_SRCS}
     )
 
-target_precompile_headers( kicommon
-    PRIVATE
-        <kicommon.h>
-        <algorithm>
-        <map>
-        <memory>
-        <optional>
-        <set>
-        <string>
-        <vector>
-        <wx/wx.h>
-         )
+if( KICAD_USE_PCH )
+    target_precompile_headers( kicommon
+        PRIVATE
+            <kicommon.h>
+            <algorithm>
+            <map>
+            <memory>
+            <optional>
+            <set>
+            <string>
+            <vector>
+            <wx/wx.h>
+             )
+endif()
 
 set_target_properties(kicommon PROPERTIES CXX_VISIBILITY_PRESET hidden)
 
@@ -750,18 +752,20 @@ add_library( common STATIC
     ${COMMON_SRCS}
     )
 
-target_precompile_headers( kicommon
-    PRIVATE
-        <kicommon.h>
-        <algorithm>
-        <map>
-        <memory>
-        <optional>
-        <set>
-        <string>
-        <vector>
-        <wx/wx.h>
-         )
+if( KICAD_USE_PCH )
+    target_precompile_headers( kicommon
+        PRIVATE
+            <kicommon.h>
+            <algorithm>
+            <map>
+            <memory>
+            <optional>
+            <set>
+            <string>
+            <vector>
+            <wx/wx.h>
+             )
+endif()
 
 add_dependencies( common version_header )
 add_dependencies( common compoundfilereader )  # used by altium_parser.cpp
@@ -929,17 +933,19 @@ set( PCB_COMMON_SRCS
 
 add_library( pcbcommon STATIC ${PCB_COMMON_SRCS} )
 
-target_precompile_headers( pcbcommon
-    PRIVATE
-        <vector>
-        <map>
-        <memory>
-        <unordered_map>
-        <board.h>
-        <footprint.h>
-        <zone.h>
-        <connectivity/connectivity_data.h>
-        <drc/drc_engine.h> )
+if( KICAD_USE_PCH )
+    target_precompile_headers( pcbcommon
+        PRIVATE
+            <vector>
+            <map>
+            <memory>
+            <unordered_map>
+            <board.h>
+            <footprint.h>
+            <zone.h>
+            <connectivity/connectivity_data.h>
+            <drc/drc_engine.h> )
+endif()
 
 target_compile_definitions(pcbcommon PRIVATE PCBNEW)
 
diff --git a/common/build_version.cpp b/common/build_version.cpp
index cef7fd092e..535eeff29e 100644
--- a/common/build_version.cpp
+++ b/common/build_version.cpp
@@ -317,6 +317,13 @@ wxString GetVersionInfoData( const wxString& aTitle, bool aHtml, bool aBrief )
     aMsg << indent4 << "KICAD_IPC_API=" << OFF;
 #endif
 
+    aMsg << indent4 << "KICAD_USE_PCH=";
+#ifdef KICAD_USE_PCH
+    aMsg << ON;
+#else
+    aMsg << OFF;
+#endif
+
 #ifndef NDEBUG
     aMsg << indent4 << "KICAD_STDLIB_DEBUG=";
 #ifdef KICAD_STDLIB_DEBUG
diff --git a/eeschema/CMakeLists.txt b/eeschema/CMakeLists.txt
index 0ef7b15ae8..96342b23f7 100644
--- a/eeschema/CMakeLists.txt
+++ b/eeschema/CMakeLists.txt
@@ -576,17 +576,19 @@ add_library( eeschema_kiface_objects OBJECT
     ${EESCHEMA_COMMON_SRCS}
     )
 
-target_precompile_headers( eeschema_kiface_objects
-    PRIVATE
-        <vector>
-        <map>
-        <memory>
-        <unordered_map>
-        <sch_edit_frame.h>
-        <string_utils.h>
-        <schematic.h>
-        <pgm_base.h>
-        <wx/wx.h> )
+if( KICAD_USE_PCH )
+    target_precompile_headers( eeschema_kiface_objects
+        PRIVATE
+            <vector>
+            <map>
+            <memory>
+            <unordered_map>
+            <sch_edit_frame.h>
+            <string_utils.h>
+            <schematic.h>
+            <pgm_base.h>
+            <wx/wx.h> )
+endif()
 
 target_include_directories( eeschema_kiface_objects
     PUBLIC
diff --git a/pcbnew/CMakeLists.txt b/pcbnew/CMakeLists.txt
index 28dfa67528..15e8aeaf27 100644
--- a/pcbnew/CMakeLists.txt
+++ b/pcbnew/CMakeLists.txt
@@ -720,7 +720,7 @@ add_library( pcbnew_kiface_objects OBJECT
     ${PCBNEW_SCRIPTING_SRCS}
     )
 
-if( CMAKE_CXX_COMPILER_ID MATCHES "Clang" )
+if( KICAD_USE_PCH AND CMAKE_CXX_COMPILER_ID MATCHES "Clang" )
     target_precompile_headers( pcbnew_kiface_objects
         PRIVATE
             <vector>