From 3f9ac6721aaeb9e9dd6347164219dc99bfde2a29 Mon Sep 17 00:00:00 2001 From: Louis Opter Date: Sat, 2 May 2026 22:22:03 +0000 Subject: [PATCH 1/2] CMake: rename QWELibClang_{BIN,BASE}_PATH to QWELibClang_LLVM_{BIN,BASE}_PATH These cache vars hold the LLVM installation prefix's bin dir and root directory -- where llvm-config and libclang.{so,dylib,dll} live -- but the unqualified names suggest "the path to the clang binary." Renaming makes the LLVM-prefix purpose explicit and frees the unqualified namespace for a separate compiler-invocation-prefix distinction introduced in a follow-up commit. No functional change. --- cmake/FindQWELibClang.cmake | 24 ++++++++++++------------ cmake/QtToolchainHelpers.cmake | 4 ++-- 2 files changed, 14 insertions(+), 14 deletions(-) diff --git a/cmake/FindQWELibClang.cmake b/cmake/FindQWELibClang.cmake index 3f6f484..ef7d570 100644 --- a/cmake/FindQWELibClang.cmake +++ b/cmake/FindQWELibClang.cmake @@ -10,7 +10,7 @@ else() endif() function(try_clang_executable Clang_EXECUTABLE) - if(NOT DEFINED QWELibClang_BIN_PATH) + if(NOT DEFINED QWELibClang_LLVM_BIN_PATH) # Extract the base dir from the clang executable if(MSVC) set(CLANG_PRINT_PATH_COMMAND /clang:-print-prog-name=clang) @@ -28,13 +28,13 @@ function(try_clang_executable Clang_EXECUTABLE) file(TO_CMAKE_PATH "${clang_output}" clang_output) # $base_path/bin/clang get_filename_component(clang_output "${clang_output}" DIRECTORY) # $base_path/bin - set(QWELibClang_BIN_PATH "${clang_output}" CACHE INTERNAL "internal") + set(QWELibClang_LLVM_BIN_PATH "${clang_output}" CACHE INTERNAL "internal") endif() # Try to find the llvm-config executable, and extract the library location from it find_program(QWELibClang_LLVM_CONFIG_EXECUTABLE NAMES llvm-config - PATHS ${QWELibClang_BIN_PATH} + PATHS ${QWELibClang_LLVM_BIN_PATH} NO_DEFAULT_PATH) if (QWELibClang_LLVM_CONFIG_EXECUTABLE) @@ -45,17 +45,17 @@ function(try_clang_executable Clang_EXECUTABLE) OUTPUT_STRIP_TRAILING_WHITESPACE ) file(TO_CMAKE_PATH "${llvm_config_output}" llvm_config_output) - get_filename_component(QWELibClang_BAS_PATH "${llvm_config_output}" DIRECTORY) + get_filename_component(QWELibClang_LLVM_BAS_PATH "${llvm_config_output}" DIRECTORY) else() # No llvm-config. Get the base path from the binary directory # This is the expected path for Windows and macOS - get_filename_component(QWELibClang_BAS_PATH "${QWELibClang_BIN_PATH}" DIRECTORY) + get_filename_component(QWELibClang_LLVM_BAS_PATH "${QWELibClang_LLVM_BIN_PATH}" DIRECTORY) endif() - set(QWELibClang_BASE_PATH ${QWELibClang_BAS_PATH} CACHE INTERNAL "internal") + set(QWELibClang_LLVM_BASE_PATH ${QWELibClang_LLVM_BAS_PATH} CACHE INTERNAL "internal") find_file(Libclang_LIBRARY NAMES libclang.dll libclang.dylib libclang.so - PATHS ${llvm_config_output} ${QWELibClang_BIN_PATH} ${QWELibClang_BASE_PATH}/lib ${QWELibClang_BASE_PATH}/lib64 + PATHS ${llvm_config_output} ${QWELibClang_LLVM_BIN_PATH} ${QWELibClang_LLVM_BASE_PATH}/lib ${QWELibClang_LLVM_BASE_PATH}/lib64 NO_DEFAULT_PATH) get_filename_component(Libclang_LIBRARY_DIR "${Libclang_LIBRARY}" DIRECTORY) @@ -110,9 +110,9 @@ if(Clang_EXECUTABLE) endif() # As a backup find the clang version used by pyside on CI -if(NOT (QWELibClang_LIBRARY_DIR AND QWELibClang_BASE_PATH AND QWELibClang_BIN_PATH) AND DEFINED ENV{LLVM_DYNAMIC_LIBS_100}) +if(NOT (QWELibClang_LIBRARY_DIR AND QWELibClang_LLVM_BASE_PATH AND QWELibClang_LLVM_BIN_PATH) AND DEFINED ENV{LLVM_DYNAMIC_LIBS_100}) unset(Clang_EXECUTABLE) - unset(QWELibClang_BIN_PATH CACHE) + unset(QWELibClang_LLVM_BIN_PATH CACHE) find_program(Clang_EXECUTABLE NAMES clang PATHS $ENV{LLVM_DYNAMIC_LIBS_100}/bin) if(Clang_EXECUTABLE) try_clang_executable(${Clang_EXECUTABLE}) @@ -122,12 +122,12 @@ endif() include(FindPackageHandleStandardArgs) find_package_handle_standard_args(QWELibClang - REQUIRED_VARS QWELibClang_LIBRARY_DIR QWELibClang_BASE_PATH QWELibClang_BIN_PATH + REQUIRED_VARS QWELibClang_LIBRARY_DIR QWELibClang_LLVM_BASE_PATH QWELibClang_LLVM_BIN_PATH VERSION_VAR QWELibClang_VERSION ) -mark_as_advanced(QWELibClang_BIN_PATH) -mark_as_advanced(QWELibClang_BASE_PATH) +mark_as_advanced(QWELibClang_LLVM_BIN_PATH) +mark_as_advanced(QWELibClang_LLVM_BASE_PATH) mark_as_advanced(QWELibClang_LIBRARY_DIR) mark_as_advanced(QWELibClang_RUNTIME_PATH) mark_as_advanced(QWELibClang_RESOURCE_PATH) diff --git a/cmake/QtToolchainHelpers.cmake b/cmake/QtToolchainHelpers.cmake index b0cd2dd..885fd53 100644 --- a/cmake/QtToolchainHelpers.cmake +++ b/cmake/QtToolchainHelpers.cmake @@ -404,7 +404,7 @@ macro(append_compiler_linker_sdk_setup) ) endif() list(APPEND gnArgArg - clang_base_path="${QWELibClang_BASE_PATH}" + clang_base_path="${QWELibClang_LLVM_BASE_PATH}" clang_version="${clang_runtime_path_version}" clang_use_chrome_plugins=false fatal_linker_warnings=false @@ -455,7 +455,7 @@ macro(append_compiler_linker_sdk_setup) endif() else() if(QT_FEATURE_use_lld_linker OR QT_FEATURE_webengine_rust_build) - list(APPEND gnArgArg clang_base_path="${QWELibClang_BASE_PATH}") + list(APPEND gnArgArg clang_base_path="${QWELibClang_LLVM_BASE_PATH}") if (QT_FEATURE_webengine_rust_build) get_clang_runtime_path_version(clang_runtime_path_version) list(APPEND gnArgArg clang_version="${clang_runtime_path_version}") From 76d33954567d9d96a738a4f1e8baea69d66286b2 Mon Sep 17 00:00:00 2001 From: Louis Opter Date: Sat, 2 May 2026 22:22:55 +0000 Subject: [PATCH 2/2] CMake: source clang_base_path from CMake-detected compiler dir The clang_base_path argument fed to Chromium's build system is used to invoke ${clang_base_path}/bin/clang++ when compiling chromium sources. Since 695dd68f8 ("Optionally build using rust"), it has been derived from QWELibClang_LLVM_BIN_PATH, which in turn is computed by running "clang -print-prog-name=clang" and taking dirname twice. That indirection produces wrong results on wrapped toolchains (ccache, distcc, sccache, nixpkgs cc-wrapper) where the wrapper script and the underlying clang live in different directories: the wrapper forwards the flag, the bare clang reports its own absolute path, and clang_base_path ends up at the bare LLVM prefix. The downstream chromium compilation then invokes the unwrapped clang, bypassing wrapper-injected flags such as -isystem for the libc++ headers, and fails on "'atomic' file not found". The print-prog-name indirection has a legitimate other purpose in this file: locating llvm-config and libclang.{so,dylib,dll}. These live in the bare LLVM prefix, not the wrapper directory, because wrappers are deliberately scoped to compile-driver flag injection: they ship the cc/c++/cpp shims plus bintools symlinks, nothing else -- no lib/ and no LLVM dev tools alongside. So we cannot simply revert the indirection; QWELibClang_LLVM_BIN_PATH and QWELibClang_LLVM_BASE_PATH remain unchanged for the libclang/llvm-config lookups they feed. Instead, introduce QWELibClang_COMPILER_BIN_PATH and QWELibClang_COMPILER_BASE_PATH, derived directly from Clang_EXECUTABLE via dirname, and route clang_base_path in QtToolchainHelpers.cmake through them. On a non-wrapped toolchain the two paths are identical, so this change is a no-op there. Reproduced on x86_64-darwin with nixpkgs (Qt 6.10.2 worked because the pre-695dd68f8 inline "dirname dirname ${CMAKE_OBJCXX_COMPILER}" ended up at the wrapper directory; Qt 6.11.0 fails). After this change, chromium compilation invokes the wrapper, NIX_CFLAGS_COMPILE flows through, and qtwebengine builds successfully. --- cmake/FindQWELibClang.cmake | 12 ++++++++++++ cmake/QtToolchainHelpers.cmake | 4 ++-- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/cmake/FindQWELibClang.cmake b/cmake/FindQWELibClang.cmake index ef7d570..62c87be 100644 --- a/cmake/FindQWELibClang.cmake +++ b/cmake/FindQWELibClang.cmake @@ -31,6 +31,15 @@ function(try_clang_executable Clang_EXECUTABLE) set(QWELibClang_LLVM_BIN_PATH "${clang_output}" CACHE INTERNAL "internal") endif() + if(NOT DEFINED QWELibClang_COMPILER_BIN_PATH) + # Directory of the compiler that CMake invokes; on a wrapped toolchain + # this differs from QWELibClang_LLVM_BIN_PATH. + get_filename_component(compiler_bin_path "${Clang_EXECUTABLE}" DIRECTORY) # $compiler_base_path/bin + get_filename_component(compiler_base_path "${compiler_bin_path}" DIRECTORY) # $compiler_base_path + set(QWELibClang_COMPILER_BIN_PATH "${compiler_bin_path}" CACHE INTERNAL "internal") + set(QWELibClang_COMPILER_BASE_PATH "${compiler_base_path}" CACHE INTERNAL "internal") + endif() + # Try to find the llvm-config executable, and extract the library location from it find_program(QWELibClang_LLVM_CONFIG_EXECUTABLE NAMES llvm-config @@ -113,6 +122,7 @@ endif() if(NOT (QWELibClang_LIBRARY_DIR AND QWELibClang_LLVM_BASE_PATH AND QWELibClang_LLVM_BIN_PATH) AND DEFINED ENV{LLVM_DYNAMIC_LIBS_100}) unset(Clang_EXECUTABLE) unset(QWELibClang_LLVM_BIN_PATH CACHE) + unset(QWELibClang_COMPILER_BIN_PATH CACHE) find_program(Clang_EXECUTABLE NAMES clang PATHS $ENV{LLVM_DYNAMIC_LIBS_100}/bin) if(Clang_EXECUTABLE) try_clang_executable(${Clang_EXECUTABLE}) @@ -128,6 +138,8 @@ find_package_handle_standard_args(QWELibClang mark_as_advanced(QWELibClang_LLVM_BIN_PATH) mark_as_advanced(QWELibClang_LLVM_BASE_PATH) +mark_as_advanced(QWELibClang_COMPILER_BIN_PATH) +mark_as_advanced(QWELibClang_COMPILER_BASE_PATH) mark_as_advanced(QWELibClang_LIBRARY_DIR) mark_as_advanced(QWELibClang_RUNTIME_PATH) mark_as_advanced(QWELibClang_RESOURCE_PATH) diff --git a/cmake/QtToolchainHelpers.cmake b/cmake/QtToolchainHelpers.cmake index 885fd53..3c86a03 100644 --- a/cmake/QtToolchainHelpers.cmake +++ b/cmake/QtToolchainHelpers.cmake @@ -404,7 +404,7 @@ macro(append_compiler_linker_sdk_setup) ) endif() list(APPEND gnArgArg - clang_base_path="${QWELibClang_LLVM_BASE_PATH}" + clang_base_path="${QWELibClang_COMPILER_BASE_PATH}" clang_version="${clang_runtime_path_version}" clang_use_chrome_plugins=false fatal_linker_warnings=false @@ -455,7 +455,7 @@ macro(append_compiler_linker_sdk_setup) endif() else() if(QT_FEATURE_use_lld_linker OR QT_FEATURE_webengine_rust_build) - list(APPEND gnArgArg clang_base_path="${QWELibClang_LLVM_BASE_PATH}") + list(APPEND gnArgArg clang_base_path="${QWELibClang_COMPILER_BASE_PATH}") if (QT_FEATURE_webengine_rust_build) get_clang_runtime_path_version(clang_runtime_path_version) list(APPEND gnArgArg clang_version="${clang_runtime_path_version}")