From 6df925b595220a0db1d7c172f15f39f4bee9f75d Mon Sep 17 00:00:00 2001 From: Brad King Date: Mon, 6 May 2024 09:59:51 -0400 Subject: cxxmodules: Do not scan sources while testing the compiler The C++ sources we use to test the compiler do not use modules. Avoid requiring a compiler that can scan just to enable the language, even when CMP0155 is NEW. The project may explicitly turn off `CMAKE_CXX_SCAN_FOR_MODULES` before adding any targets. Fixes: #25956 --- Modules/CMakeDetermineCompilerABI.cmake | 3 +++ Modules/CMakeTestCXXCompiler.cmake | 13 +++++++++++++ 2 files changed, 16 insertions(+) diff --git a/Modules/CMakeDetermineCompilerABI.cmake b/Modules/CMakeDetermineCompilerABI.cmake index efc18f9..b21ec73 100644 --- a/Modules/CMakeDetermineCompilerABI.cmake +++ b/Modules/CMakeDetermineCompilerABI.cmake @@ -34,6 +34,9 @@ function(CMAKE_DETERMINE_COMPILER_ABI lang src) endif() set(CMAKE_${lang}_RUNTIME_LIBRARY "Static") endif() + if(lang STREQUAL "CXX") + set(CMAKE_${lang}_SCAN_FOR_MODULES OFF) + endif() if(NOT "x${CMAKE_${lang}_COMPILER_ID}" STREQUAL "xMSVC") # Avoid adding our own platform standard libraries for compilers # from which we might detect implicit link libraries. diff --git a/Modules/CMakeTestCXXCompiler.cmake b/Modules/CMakeTestCXXCompiler.cmake index e640ff9..a9fbb26 100644 --- a/Modules/CMakeTestCXXCompiler.cmake +++ b/Modules/CMakeTestCXXCompiler.cmake @@ -37,6 +37,13 @@ endif() # any makefiles or projects. if(NOT CMAKE_CXX_COMPILER_WORKS) PrintTestCompilerStatus("CXX") + # FIXME: Use a block() to isolate the variables we set/unset here. + if(DEFINED CMAKE_CXX_SCAN_FOR_MODULES) + set(__CMAKE_SAVED_CXX_SCAN_FOR_MODULES "${CMAKE_CXX_SCAN_FOR_MODULES}") + else() + unset(__CMAKE_SAVED_CXX_SCAN_FOR_MODULES) + endif() + set(CMAKE_CXX_SCAN_FOR_MODULES OFF) __TestCompiler_setTryCompileTargetType() string(CONCAT __TestCompiler_testCXXCompilerSource "#ifndef __cplusplus\n" @@ -49,6 +56,12 @@ if(NOT CMAKE_CXX_COMPILER_WORKS) try_compile(CMAKE_CXX_COMPILER_WORKS SOURCE_FROM_VAR testCXXCompiler.cxx __TestCompiler_testCXXCompilerSource OUTPUT_VARIABLE __CMAKE_CXX_COMPILER_OUTPUT) + if(DEFINED __CMAKE_SAVED_CXX_SCAN_FOR_MODULES) + set(CMAKE_CXX_SCAN_FOR_MODULES "${__CMAKE_SAVED_CXX_SCAN_FOR_MODULES}") + unset(__CMAKE_SAVED_CXX_SCAN_FOR_MODULES) + else() + unset(CMAKE_CXX_SCAN_FOR_MODULES) + endif() unset(__TestCompiler_testCXXCompilerSource) # Move result from cache to normal variable. set(CMAKE_CXX_COMPILER_WORKS ${CMAKE_CXX_COMPILER_WORKS}) -- cgit v0.12