From 75b9b6c7c23ecd100b868bf397f3e6f4eddb7e32 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sun, 12 Mar 2023 13:34:08 +0000
Subject: [PATCH 1/6] [FIXUP] cmake: Drop C language from the global project

Must be squashed with the commit 91f28a6a961f962e0408130cbc46d9aa8cc4b84b
"cmake: Add root `CMakeLists.txt` file".
---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 35ea1d0bdbb76..9424387a90c8d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,7 @@ project("Bitcoin Core"
   VERSION 24.99.0
   DESCRIPTION "Bitcoin client software"
   HOMEPAGE_URL "https://bitcoincore.org/"
-  LANGUAGES CXX C ASM
+  LANGUAGES CXX ASM
 )
 
 set(CLIENT_VERSION_IS_RELEASE "false")

From 3bb3448b90e0664da9cf57a90a063ad5555e5ac2 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sun, 12 Mar 2023 13:34:25 +0000
Subject: [PATCH 2/6] [FIXUP] cmake: Enable C language for libsecp256k1

Must be squashed with the commit eb3546f2235fe135328b2999053a9692d80cd6e0
"cmake: Build `secp256k1` static library".
---
 cmake/secp256k1.cmake | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cmake/secp256k1.cmake b/cmake/secp256k1.cmake
index d965493e79749..fd1d04198ec09 100644
--- a/cmake/secp256k1.cmake
+++ b/cmake/secp256k1.cmake
@@ -6,6 +6,7 @@
 # support has been merged we should switch to using the upstream CMake
 # buildsystem.
 
+enable_language(C)
 set(CMAKE_C_STANDARD 90)
 set(CMAKE_C_EXTENSIONS OFF)
 

From d37c9a248432bb9ec56f2bd9025e0b895f46c737 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Fri, 24 Mar 2023 17:47:57 +0000
Subject: [PATCH 3/6] [FIXUP] cmake: Ensure C language is disabled for
 FindThreads

Must be squashed with the commit d028a49c35abe55d6f53c2515cab30d30e726b08
"cmake: Build `bitcoin_util` static library".
---
 cmake/module/AddThreadsIfNeeded.cmake | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/cmake/module/AddThreadsIfNeeded.cmake b/cmake/module/AddThreadsIfNeeded.cmake
index d11e9e5205566..2939f1a0c6fcb 100644
--- a/cmake/module/AddThreadsIfNeeded.cmake
+++ b/cmake/module/AddThreadsIfNeeded.cmake
@@ -7,8 +7,17 @@ function(add_threads_if_needed)
   #       require Threads. Therefore, a proper check will be
   #       appropriate here.
 
+  if(CMAKE_C_COMPILER_LOADED)
+    message(FATAL_ERROR [=[
+  To make FindThreads check C++ language features, C language must be
+  disabled. This is essential, at least, when cross-compiling for MinGW-w64
+  because two different threading models are available.
+    ]=] )
+  endif()
+
   set(THREADS_PREFER_PTHREAD_FLAG ON)
   find_package(Threads REQUIRED)
+  set_target_properties(Threads::Threads PROPERTIES IMPORTED_GLOBAL TRUE)
 
   set(thread_local)
   if(MINGW)

From e5e6bd3a4b1b65e207c342b6f9362086f9cfded7 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Fri, 24 Mar 2023 20:33:34 +0000
Subject: [PATCH 4/6] build: Generate `share/toolchain.cmake` in  depends

---
 depends/Makefile           |  32 ++++++++-
 depends/toolchain.cmake.in | 137 +++++++++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+), 1 deletion(-)
 create mode 100644 depends/toolchain.cmake.in

diff --git a/depends/Makefile b/depends/Makefile
index 27bf804c6b09b..3f1bcaa8bb669 100644
--- a/depends/Makefile
+++ b/depends/Makefile
@@ -190,6 +190,7 @@ $(host_arch)_$(host_os)_native_toolchain?=$($(host_os)_native_toolchain)
 include funcs.mk
 
 final_build_id_long+=$(shell $(build_SHA256SUM) config.site.in)
+final_build_id_long+=$(shell $(build_SHA256SUM) toolchain.cmake.in)
 final_build_id+=$(shell echo -n "$(final_build_id_long)" | $(build_SHA256SUM) | cut -c-$(HASH_LENGTH))
 $(host_prefix)/.stamp_$(final_build_id): $(native_packages) $(packages)
 	rm -rf $(@D)
@@ -257,6 +258,34 @@ $(host_prefix)/share/config.site : config.site.in $(host_prefix)/.stamp_$(final_
             $< > $@
 	touch $@
 
+$(host_prefix)/share/toolchain.cmake : toolchain.cmake.in $(host_prefix)/.stamp_$(final_build_id)
+	@mkdir -p $(@D)
+	sed -e 's|@host_system@|$($(host_os)_cmake_system)|' \
+            -e 's|@host_arch@|$(host_arch)|' \
+            -e 's|@CC@|$(host_CC)|' \
+            -e 's|@CXX@|$(host_CXX)|' \
+            -e 's|@AR@|$(host_AR)|' \
+            -e 's|@RANLIB@|$(host_RANLIB)|' \
+            -e 's|@STRIP@|$(host_STRIP)|' \
+            -e 's|@OBJCOPY@|$(host_OBJCOPY)|' \
+            -e 's|@INSTALL_NAME_TOOL@|$(host_INSTALL_NAME_TOOL)|' \
+            -e 's|@OTOOL@|$(host_OTOOL)|' \
+            -e 's|@depends_prefix@|$(host_prefix)|' \
+            -e 's|@CFLAGS@|$(strip $(host_CFLAGS) $(host_$(release_type)_CFLAGS))|' \
+            -e 's|@CXXFLAGS@|$(strip $(host_CXXFLAGS) $(host_$(release_type)_CXXFLAGS))|' \
+            -e 's|@CPPFLAGS@|$(strip $(host_CPPFLAGS) $(host_$(release_type)_CPPFLAGS))|' \
+            -e 's|@allow_host_packages@|$(ALLOW_HOST_PACKAGES)|' \
+            -e 's|@no_qt@|$(NO_QT)|' \
+            -e 's|@no_qr@|$(NO_QR)|' \
+            -e 's|@no_zmq@|$(NO_ZMQ)|' \
+            -e 's|@no_wallet@|$(NO_WALLET)|' \
+            -e 's|@no_bdb@|$(NO_BDB)|' \
+            -e 's|@no_sqlite@|$(NO_SQLITE)|' \
+            -e 's|@no_upnp@|$(NO_UPNP)|' \
+            -e 's|@no_natpmp@|$(NO_NATPMP)|' \
+            -e 's|@no_usdt@|$(NO_USDT)|' \
+            $< > $@
+	touch $@
 
 define check_or_remove_cached
   mkdir -p $(BASE_CACHE)/$(host)/$(package) && cd $(BASE_CACHE)/$(host)/$(package); \
@@ -278,6 +307,7 @@ check-sources:
 	@$(foreach package,$(all_packages),$(call check_or_remove_sources,$(package));)
 
 $(host_prefix)/share/config.site: check-packages
+$(host_prefix)/share/toolchain.cmake: check-packages
 
 check-packages: check-sources
 
@@ -287,7 +317,7 @@ clean-all: clean
 clean:
 	@rm -rf $(WORK_PATH) $(BASE_CACHE) $(BUILD) *.log
 
-install: check-packages $(host_prefix)/share/config.site
+install: check-packages $(host_prefix)/share/config.site $(host_prefix)/share/toolchain.cmake
 
 
 download-one: check-sources $(all_sources)
diff --git a/depends/toolchain.cmake.in b/depends/toolchain.cmake.in
new file mode 100644
index 0000000000000..59c98d745209d
--- /dev/null
+++ b/depends/toolchain.cmake.in
@@ -0,0 +1,137 @@
+# This file is expected to be highly volatile and may still change substantially.
+
+set(CMAKE_SYSTEM_NAME @host_system@)
+set(CMAKE_SYSTEM_PROCESSOR @host_arch@)
+
+function(split_compiler_launcher env_compiler launcher compiler)
+  set(${launcher})
+  list(GET ${env_compiler} 0 start_token)
+  if(start_token STREQUAL "env")
+    set(${compiler})
+    set(env_arg_parsing TRUE)
+    foreach(token IN LISTS ${env_compiler})
+      if(env_arg_parsing)
+        list(APPEND ${launcher} ${token})
+        set(env_arg_parsing FALSE)
+        continue()
+      elseif(token STREQUAL "-u")
+        list(APPEND ${launcher} ${token})
+        set(env_arg_parsing TRUE)
+        continue()
+      endif()
+      list(APPEND ${compiler} ${token})
+    endforeach()
+  else()
+    set(${compiler} ${${env_compiler}})
+  endif()
+  set(${launcher} ${${launcher}} PARENT_SCOPE)
+  set(${compiler} ${${compiler}} PARENT_SCOPE)
+endfunction()
+
+if(NOT CMAKE_C_COMPILER)
+  set(DEPENDS_C_COMPILER_WITH_LAUNCHER @CC@)
+  split_compiler_launcher(DEPENDS_C_COMPILER_WITH_LAUNCHER CMAKE_C_COMPILER_LAUNCHER CMAKE_C_COMPILER)
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21)
+    set(CMAKE_C_LINKER_LAUNCHER ${CMAKE_C_COMPILER_LAUNCHER})
+  endif()
+  if(CMAKE_VERSION VERSION_LESS 3.19)
+    set(DEPENDS_C_COMPILER_FLAGS ${CMAKE_C_COMPILER})
+    list(REMOVE_AT DEPENDS_C_COMPILER_FLAGS 0)
+    string(REPLACE ";" " " DEPENDS_C_COMPILER_FLAGS "${DEPENDS_C_COMPILER_FLAGS}")
+    list(GET CMAKE_C_COMPILER 0 CMAKE_C_COMPILER)
+  endif()
+endif()
+set(CMAKE_C_FLAGS_INIT "${DEPENDS_C_COMPILER_FLAGS} @CPPFLAGS@ @CFLAGS@")
+
+if(NOT CMAKE_CXX_COMPILER)
+  set(DEPENDS_CXX_COMPILER_WITH_LAUNCHER @CXX@)
+  split_compiler_launcher(DEPENDS_CXX_COMPILER_WITH_LAUNCHER CMAKE_CXX_COMPILER_LAUNCHER CMAKE_CXX_COMPILER)
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21)
+    set(CMAKE_CXX_LINKER_LAUNCHER ${CMAKE_CXX_COMPILER_LAUNCHER})
+  endif()
+  if(CMAKE_VERSION VERSION_LESS 3.19)
+    set(DEPENDS_CXX_COMPILER_FLAGS ${CMAKE_CXX_COMPILER})
+    list(REMOVE_AT DEPENDS_CXX_COMPILER_FLAGS 0)
+    string(REPLACE ";" " " DEPENDS_CXX_COMPILER_FLAGS "${DEPENDS_CXX_COMPILER_FLAGS}")
+    list(GET CMAKE_CXX_COMPILER 0 CMAKE_CXX_COMPILER)
+  endif()
+endif()
+set(CMAKE_CXX_FLAGS_INIT "${DEPENDS_CXX_COMPILER_FLAGS} @CPPFLAGS@ @CXXFLAGS@")
+
+if(NOT CMAKE_OBJCXX_COMPILER)
+  set(DEPENDS_OBJCXX_COMPILER_WITH_LAUNCHER @CXX@)
+  split_compiler_launcher(DEPENDS_OBJCXX_COMPILER_WITH_LAUNCHER CMAKE_OBJCXX_COMPILER_LAUNCHER CMAKE_OBJCXX_COMPILER)
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21)
+    set(CMAKE_OBJCXX_LINKER_LAUNCHER ${CMAKE_OBJCXX_COMPILER_LAUNCHER})
+  endif()
+  if(CMAKE_VERSION VERSION_LESS 3.19)
+    set(DEPENDS_OBJCXX_COMPILER_FLAGS ${CMAKE_OBJCXX_COMPILER})
+    list(REMOVE_AT DEPENDS_OBJCXX_COMPILER_FLAGS 0)
+    string(REPLACE ";" " " DEPENDS_OBJCXX_COMPILER_FLAGS "${DEPENDS_OBJCXX_COMPILER_FLAGS}")
+    list(GET CMAKE_OBJCXX_COMPILER 0 CMAKE_OBJCXX_COMPILER)
+  endif()
+endif()
+set(CMAKE_OBJCXX_FLAGS_INIT "${DEPENDS_OBJCXX_COMPILER_FLAGS} @CPPFLAGS@ @CXXFLAGS@")
+
+set(CMAKE_AR "@AR@")
+set(CMAKE_RANLIB "@RANLIB@")
+set(CMAKE_STRIP "@STRIP@")
+set(CMAKE_OBJCOPY "@OBJCOPY@")
+set(CMAKE_INSTALL_NAME_TOOL "@INSTALL_NAME_TOOL@")
+set(OTOOL "@OTOOL@")
+
+set(CMAKE_FIND_ROOT_PATH "@depends_prefix@")
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+set(PKG_CONFIG_PATH "@depends_prefix@/lib/pkgconfig")
+if("@allow_host_packages@" STREQUAL "1")
+  set(DEPENDS_ALLOW_HOST_PACKAGES TRUE)
+else()
+  set(DEPENDS_ALLOW_HOST_PACKAGES FALSE)
+  set(PKG_CONFIG_LIBDIR "${PKG_CONFIG_PATH}")
+endif()
+set(QT_TRANSLATIONS_DIR "@depends_prefix@/translations")
+
+if(NOT WITH_GUI AND "@no_qt@" STREQUAL "1")
+  set(WITH_GUI "no" CACHE STRING "")
+endif()
+
+if(NOT WITH_QRENCODE AND "@no_qr@" STREQUAL "1")
+  set(WITH_QRENCODE OFF CACHE STRING "")
+endif()
+
+if(NOT WITH_ZMQ AND "@no_zmq@" STREQUAL "1")
+  set(WITH_ZMQ OFF CACHE STRING "")
+endif()
+
+if(NOT ENABLE_WALLET AND "@no_wallet@" STREQUAL "1")
+  set(ENABLE_WALLET OFF CACHE BOOL "")
+endif()
+
+if(NOT WITH_BDB AND "@no_bdb@" STREQUAL "1")
+  set(WITH_BDB OFF CACHE STRING "")
+endif()
+
+if(NOT WITH_SQLITE AND "@no_sqlite@" STREQUAL "1")
+  set(WITH_SQLITE OFF CACHE STRING "")
+endif()
+
+if(NOT WITH_MINIUPNPC AND "@no_upnp@" STREQUAL "1")
+  set(WITH_MINIUPNPC OFF CACHE STRING "")
+endif()
+
+if(NOT WITH_NATPMP AND "@no_natpmp@" STREQUAL "1")
+  set(WITH_NATPMP OFF CACHE STRING "")
+endif()
+
+if(NOT WITH_USDT AND "@no_usdt@" STREQUAL "1")
+  set(WITH_USDT OFF CACHE STRING "")
+endif()
+
+if(DEFINED ENV{PYTHONPATH})
+  set(PYTHONPATH "@depends_prefix@/native/lib/python3/dist-packages:$ENV{PYTHONPATH}")
+else()
+  set(PYTHONPATH "@depends_prefix@/native/lib/python3/dist-packages")
+endif()

From a8917aba8933772dba00fde33b0988fbca9f0174 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sun, 12 Mar 2023 17:15:42 +0000
Subject: [PATCH 5/6] cmake: Add cross-compiling support

To configure CMake for cross-compiling, use
`--toolchain depends/${HOST}/share/toolchain.cmake` command-line option.
---
 CMakeLists.txt                         | 10 ++++++++++
 cmake/module/AddLibeventIfNeeded.cmake |  6 +++---
 cmake/module/CrossPkgConfig.cmake      | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 cmake/module/CrossPkgConfig.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9424387a90c8d..110619e53efff 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -98,6 +98,10 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   add_compile_definitions(MAC_OSX)
 endif()
 
+if(CMAKE_CROSSCOMPILING AND DEPENDS_ALLOW_HOST_PACKAGES)
+  list(APPEND CMAKE_FIND_ROOT_PATH "${CMAKE_SYSTEM_PREFIX_PATH}")
+endif()
+
 include(AddThreadsIfNeeded)
 add_threads_if_needed()
 
@@ -127,6 +131,12 @@ message("=================")
 message("Executables:")
 message("  bitcoind ............................ ${BUILD_DAEMON}")
 message("")
+if(CMAKE_CROSSCOMPILING)
+  set(cross_status "TRUE, for ${CMAKE_SYSTEM_NAME}, ${CMAKE_SYSTEM_PROCESSOR}")
+else()
+  set(cross_status "FALSE")
+endif()
+message("Cross compiling ....................... ${cross_status}")
 get_directory_property(definitions COMPILE_DEFINITIONS)
 string(REPLACE ";" " " definitions "${definitions}")
 message("Preprocessor defined macros ........... ${definitions}")
diff --git a/cmake/module/AddLibeventIfNeeded.cmake b/cmake/module/AddLibeventIfNeeded.cmake
index 186095700b83a..d6e6ff1397ab7 100644
--- a/cmake/module/AddLibeventIfNeeded.cmake
+++ b/cmake/module/AddLibeventIfNeeded.cmake
@@ -37,8 +37,8 @@ function(add_libevent_if_needed)
     return()
   endif()
 
-  find_package(PkgConfig)
-  pkg_check_modules(libevent REQUIRED libevent>=${libevent_minimum_version} IMPORTED_TARGET GLOBAL)
+  include(CrossPkgConfig)
+  cross_pkg_check_modules(libevent REQUIRED libevent>=${libevent_minimum_version} IMPORTED_TARGET GLOBAL)
   check_evhttp_connection_get_peer(PkgConfig::libevent)
   target_link_libraries(PkgConfig::libevent INTERFACE
     $<$<BOOL:${MINGW}>:iphlpapi;ws2_32>
@@ -46,6 +46,6 @@ function(add_libevent_if_needed)
   add_library(libevent::libevent ALIAS PkgConfig::libevent)
 
   if(NOT WIN32)
-    pkg_check_modules(libevent_pthreads REQUIRED libevent_pthreads>=${libevent_minimum_version} IMPORTED_TARGET)
+    cross_pkg_check_modules(libevent_pthreads REQUIRED libevent_pthreads>=${libevent_minimum_version} IMPORTED_TARGET)
   endif()
 endfunction()
diff --git a/cmake/module/CrossPkgConfig.cmake b/cmake/module/CrossPkgConfig.cmake
new file mode 100644
index 0000000000000..4d845a60fe3e3
--- /dev/null
+++ b/cmake/module/CrossPkgConfig.cmake
@@ -0,0 +1,19 @@
+# Copyright (c) 2023 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+find_package(PkgConfig REQUIRED)
+
+macro(cross_pkg_check_modules)
+  if(CMAKE_CROSSCOMPILING)
+    set(pkg_config_path_saved "$ENV{PKG_CONFIG_PATH}")
+    set(pkg_config_libdir_saved "$ENV{PKG_CONFIG_LIBDIR}")
+    set(ENV{PKG_CONFIG_PATH} ${PKG_CONFIG_PATH})
+    set(ENV{PKG_CONFIG_LIBDIR} ${PKG_CONFIG_LIBDIR})
+    pkg_check_modules(${ARGV})
+    set(ENV{PKG_CONFIG_PATH} ${pkg_config_path_saved})
+    set(ENV{PKG_CONFIG_LIBDIR} ${pkg_config_libdir_saved})
+  else()
+    pkg_check_modules(${ARGV})
+  endif()
+endmacro()

From b0351e34b79c0b361623f9bb923dcfd4129344f5 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Mon, 13 Mar 2023 17:24:26 +0000
Subject: [PATCH 6/6] [FIXUP] cmake: Rework PIC/PIE logic

Must be squashed with the commit 91f28a6a961f962e0408130cbc46d9aa8cc4b84b
"cmake: Add root `CMakeLists.txt` file".
---
 CMakeLists.txt | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 110619e53efff..c9d4fc6dec212 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,16 +52,6 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
 set(configure_warnings)
-if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.14)
-  include(CheckPIESupported)
-  check_pie_supported(OUTPUT_VARIABLE check_pie_output LANGUAGES CXX)
-  if(NOT CMAKE_CXX_LINK_PIE_SUPPORTED)
-    list(APPEND configure_warnings "PIE link options are not supported for executable targets: ${check_pie_output}.")
-  endif()
-else()
-  list(APPEND configure_warnings "No PIE options will be passed to a linker for executable targets.")
-endif()
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 if(WIN32)
   #[=[
@@ -123,6 +113,19 @@ include(cmake/secp256k1.cmake)
 include(CheckStdFilesystem)
 check_std_filesystem()
 
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.14)
+  include(CheckPIESupported)
+  check_pie_supported(OUTPUT_VARIABLE check_pie_output LANGUAGES CXX)
+  if(CMAKE_CXX_LINK_PIE_SUPPORTED)
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+  endif()
+else()
+  check_cxx_source_links_with_flags(-fPIE "int main(){}" COMPILER_SUPPORTS_PIE)
+  if(COMPILER_SUPPORTS_PIE)
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+  endif()
+endif()
+
 add_subdirectory(src)
 
 message("\n")