echo/CMake
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

CheckSymbolExists: Work around GCC failure with -pedantic-errors option

Browse Source 
GCC mistakenly issues the pedantic warning "ISO C forbids conversion of
function pointer to object pointer type". With -pedantic-errors in the
compile flags, that diagnostic prevents check_symbol_exists() from
detecting function symbols.

The solution is to filter out -pedantic-errors (and -Werror, just to be
future proof) before invoking try_compile().

Fixes: #13208
This commit is contained in:
Timo Röhling 2021-10-22 15:47:14 +02:00
parent ca3e83250f
commit 1ab7c3cd28
2 changed files with 26 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
Modules/CheckSymbolExists.cmake
View File

@ -67,14 +67,29 @@ cmake_policy(SET CMP0054 NEW) # if() quoted variables not dereferenced
macro(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
if(CMAKE_C_COMPILER_LOADED)
__CHECK_SYMBOL_EXISTS_FILTER_FLAGS(C)
__CHECK_SYMBOL_EXISTS_IMPL("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
__CHECK_SYMBOL_EXISTS_RESTORE_FLAGS(C)
elseif(CMAKE_CXX_COMPILER_LOADED)
__CHECK_SYMBOL_EXISTS_FILTER_FLAGS(CXX)
__CHECK_SYMBOL_EXISTS_IMPL("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
__CHECK_SYMBOL_EXISTS_RESTORE_FLAGS(CXX)
else()
message(FATAL_ERROR "CHECK_SYMBOL_EXISTS needs either C or CXX language enabled")
endif()
endmacro()
macro(__CHECK_SYMBOL_EXISTS_FILTER_FLAGS LANG)
set(__CMAKE_${LANG}_FLAGS_SAVED "${CMAKE_${LANG}_FLAGS}")
string(REGEX REPLACE "(^| )-Werror([= ][^ ]*)?( |$)" " " CMAKE_${LANG}_FLAGS "${CMAKE_${LANG}_FLAGS}")
string(REGEX REPLACE "(^| )-pedantic-errors( |$)" " " CMAKE_${LANG}_FLAGS "${CMAKE_${LANG}_FLAGS}")
endmacro()
macro(__CHECK_SYMBOL_EXISTS_RESTORE_FLAGS LANG)
set(CMAKE_${LANG}_FLAGS "${__CMAKE_${LANG}_FLAGS_SAVED}")
unset(__CMAKE_${LANG}_FLAGS_SAVED)
endmacro()
macro(__CHECK_SYMBOL_EXISTS_IMPL SOURCEFILE SYMBOL FILES VARIABLE)
if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}")
set(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")

11
Tests/CMakeOnly/CheckSymbolExists/CMakeLists.txt
View File

@ -48,4 +48,15 @@ if (CMAKE_COMPILER_IS_GNUCC)
if (CSE_RESULT_O3)
message(SEND_ERROR "CheckSymbolExists reported a nonexistent symbol as existing with optimization -O3")
endif ()
string(APPEND CMAKE_C_FLAGS " -pedantic-errors")
unset(CS_RESULT_PEDANTIC_ERRORS CACHE)
message(STATUS "Testing with -pedantic-errors")
check_symbol_exists(fopen "stdio.h" CSE_RESULT_PEDANTIC_ERRORS)
if(NOT CSE_RESULT_PEDANTIC_ERRORS)
message(SEND_ERROR "CheckSymbolExists reported an existing symbol as nonexisting with -pedantic-errors")
endif()
endif ()