MantisBT - CMake

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Date Submitted

Last Update

0008787

CMake

public

2009-03-24 18:40

2013-10-21 11:21

Reporter

Daniel Nelson

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

won't fix

Platform

OS Version

Product Version

CMake-2-6

Target Version

Fixed in Version

Summary

0008787: set_property on sources causing extra files to be rebuilt

Description

I am using set_property to add extra compile flags to source files that are
built using a precompiled header, but whenever a source file is added or
removed it causes every file in the executable to be rebuilt. I have come up
with a CMakeList that shows the issue.

#####
cmake_minimum_required(VERSION 2.6)
project(prop_test)
set(sources foo.cpp bar.cpp main.cpp)
add_executable(prop_test ${sources})
set_property(SOURCE foo.cpp main.cpp APPEND PROPERTY COMPILE_FLAGS -Wall)
#####

If you compile the project using a Makefile generator, then remove foo.cpp from
the sources variable and recompile, it will also recompile main.cpp and
bar.cpp even though no compile flags have changed. If you then put foo.cpp
back and build it will again rebuild main.cpp and bar.cpp. It seems that you
will need to rebuild every source file that is used in the executable, even
though nothing has changed.

The problem appears to be that all files depend on flags.make so they will be rebuilt if a flag changes. But since they all share the same flags.make, they will always be rebuilt as a group. Perhaps we could write a separate flags.make file for every object file that has compile/define flags set?

Steps To Reproduce

Additional Information