[CMake] avoid rebuilding targets depending on generated source files
Michael Hertling
mhertling at online.de
Sun Mar 4 19:05:05 EST 2012
On 03/04/2012 08:02 PM, Ajay Panyala wrote:
> The following project is a boiled-down version of yours but doesn't
> need any programs except for CMake - that's what I actually meant
> with "minimal but complete" as I don't have the org.antlr.Tool
> Java program:
>
> I am sorry. I was mainly trying to cleanup the big CMakeLists file
> I had and removed about 10 different targets - all of which were
> rebuilt because the 5 files (test*.*) were overwritten.
>
> If you want to try running the test project on your system
>
> test.g is at http://pastie.org/private/agzor3ibzoa5pom6q31qq
>
> org.antlr.Tool is at www.antlr.org/download/antlr-3.4-complete.jar
>
> After configuration, you can run the target by "make X=0" and check the
> timestamps by "ls -l --full-time test.tokens parser src". Issuing "make
> X=0" again reveals that the copied files aren't rewritten as it happens
> after "make X=1". Thus, AFAICS, everything works as expected. Could you
> check if the above-noted example also works on your system?
>
> It does not work. The files are still overwritten.
Could you run the following shell script in a build tree configured
with the CMakeLists.txt from my previous reply and post the output?
# check.sh:
make X=0 2>&1 > /dev/null
echo "After make X=0 (1):"
echo "-------------------"
echo ""
ls --full-time test.tokens src parser
echo -ne "\n\n"
sleep 3
make X=0 2>&1 > /dev/null
echo "After make X=0 (2):"
echo "-------------------"
echo ""
ls --full-time test.tokens src parser
echo -ne "\n\n"
sleep 3
make X=1 2>&1 > /dev/null
echo "After make X=1:"
echo "---------------"
echo ""
ls --full-time test.tokens src parser
# End of check.sh
BTW, which CMake version do you use?
Regards,
Michael
PS: Could you set up your e-mail client so that it marks quoted
text in some way? Currently, one can't distinguish between
the lines you are writing and the lines written by others.
> What exactly does not work with your example? You wrote:
>
>>>> I have 4 cmake -E copy_if_different commands, one for each file.
>>>> Only the last file is not copied (if similar). [...]
>
> Does this mean that the last file out of four - in fact, your example
> handles five files - is not copied *although* the source file and the
> destination file are different, i.e. similar but not equal?
>
> Yes the file test.tokens is not copied overwritten since they are
> exactly (diff) similar files. This is the case with the other 4 files as
> well,
> but they are still copied over and rewritten.
>
>
> You wrote further:
>
>>>> [...] The others are copied
>>>> even if they are the same.
>>>>
>>>> I verfied that they are the same with a diff.
>
> Does this mean that source files are copied *although* they are equal
> to their respective destination file? How do you determine that they
> have been copied? Do you check the timestamps? With --full-time?
>
> Yes, I do check with ls -l --full-time. Except test.tokens, all the other
> files
> are copied over (rewritten) even though they are exactly the same (diff
> same I mean).
>
> This is what is confusing me about the behavior of copy_if_different.
> that is why it works only with test.tokens and not others.
>
> PS: Does org.antlr.Tool write to the source tree? If so: Don't do that.
>
> Yes, it generates the files in the source dir itself (where test.g is
> present)
> I now modified CMakeLists to copy test.g to the project build folder and
> run it there. The new CMakeLists is at
>
> http://pastie.org/private/p1yi0l8so9cqimqlywfmhw
>
>
> Thank You
> Ajay
>
> On Sun, Mar 4, 2012 at 12:52 AM, Michael Hertling <mhertling at online.de>wrote:
>
>> On 03/04/2012 01:06 AM, Ajay Panyala wrote:
>>> Please provide a minimal but complete example for this issue.
>>>
>>> Please find it in the following link
>>> http://pastie.org/private/pd13u33s9xpfihf2dbzc1q
>>
>>
>
>
>> The following project is a boiled-down version of yours but doesn't
>> need any programs except for CMake - that's what I actually meant
>> with "minimal but complete" as I don't have the org.antlr.Tool
>> Java program:
>>
>> CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
>> PROJECT(P NONE)
>> SET(CMAKE_VERBOSE_MAKEFILE ON)
>>
>> SET(GrammarSource ${PROJECT_BINARY_DIR}/src)
>> FILE(MAKE_DIRECTORY ${PROJECT_BINARY_DIR}/src)
>>
>> ADD_CUSTOM_TARGET(GrammarBuild ALL
>> COMMAND ${CMAKE_COMMAND} -E echo "\${X}"
>> > ${GrammarSource}/testLexer.h
>> COMMAND ${CMAKE_COMMAND} -E echo "\${X}"
>> > ${GrammarSource}/testLexer.c
>> COMMAND ${CMAKE_COMMAND} -E echo "\${X}"
>> > ${GrammarSource}/testParser.h
>> COMMAND ${CMAKE_COMMAND} -E echo "\${X}"
>> > ${GrammarSource}/testParser.c
>> COMMAND ${CMAKE_COMMAND} -E echo "\${X}"
>> > ${PROJECT_BINARY_DIR}/test.tokens
>> )
>>
>> ADD_CUSTOM_COMMAND(TARGET GrammarBuild POST_BUILD
>> COMMAND ${CMAKE_COMMAND} -E copy_if_different
>> ${GrammarSource}/testLexer.h
>> ${PROJECT_BINARY_DIR}/parser/testLexer.h
>> COMMAND ${CMAKE_COMMAND} -E copy_if_different
>> ${GrammarSource}/testLexer.c
>> ${PROJECT_BINARY_DIR}/parser/testLexer.c
>> COMMAND ${CMAKE_COMMAND} -E copy_if_different
>> ${GrammarSource}/testParser.h
>> ${PROJECT_BINARY_DIR}/parser/testParser.h
>> COMMAND ${CMAKE_COMMAND} -E copy_if_different
>> ${GrammarSource}/testParser.c
>> ${PROJECT_BINARY_DIR}/parser/testParser.c
>> COMMAND ${CMAKE_COMMAND} -E copy_if_different
>> ${PROJECT_BINARY_DIR}/test.tokens
>> ${PROJECT_BINARY_DIR}/parser/test.tokens
>> )
>>
>> After configuration, you can run the target by "make X=0" and check the
>> timestamps by "ls -l --full-time test.tokens parser src". Issuing "make
>> X=0" again reveals that the copied files aren't rewritten as it happens
>> after "make X=1". Thus, AFAICS, everything works as expected. Could you
>> check if the above-noted example also works on your system?
>>
>> What exactly does not work with your example? You wrote:
>>
>>>>> I have 4 cmake -E copy_if_different commands, one for each file.
>>>>> Only the last file is not copied (if similar). [...]
>>
>> Does this mean that the last file out of four - in fact, your example
>> handles five files - is not copied *although* the source file and the
>> destination file are different, i.e. similar but not equal?
>>
>> You wrote further:
>>
>>>>> [...] The others are copied
>>>>> even if they are the same.
>>>>>
>>>>> I verfied that they are the same with a diff.
>>
>> Does this mean that source files are copied *although* they are equal
>> to their respective destination file? How do you determine that they
>> have been copied? Do you check the timestamps? With --full-time?
>>
>> Regards,
>>
>> Michael
>>
>> PS: Does org.antlr.Tool write to the source tree? If so: Don't do that.
>>
>>> On Sat, Mar 3, 2012 at 3:54 PM, Michael Hertling <mhertling at online.de
>>> wrote:
>>>
>>>> On 03/04/2012 12:14 AM, Ajay Panyala wrote:
>>>>> No, it wouldn't; check it out:
>>>>>
>>>>> % touch a
>>>>> % rm -f b
>>>>> % ls b
>>>>> ls: cannot access b: No such file or directory
>>>>> % cmake -E copy_if_different a b
>>>>> % ls b
>>>>> b
>>>>> % cksum a b
>>>>> 4294967295 0 a
>>>>> 4294967295 0 b
>>>>>
>>>>> It works with one file, but I have 4 files that are generated.
>>>>> I have 4 cmake -E copy_if_different commands, one for each file.
>>>>> Only the last file is not copied (if similar). The others are copied
>>>>> even if they are the same.
>>>>>
>>>>> I verfied that they are the same with a diff.
>>>>>
>>>>> Any idea what might be happening here ?
>>>>
>>>> Please provide a minimal but complete example for this issue.
>>>>
>>>> Regards,
>>>>
>>>> Michael
>>>>
>>>>> On Sat, Mar 3, 2012 at 2:47 PM, Michael Hertling <mhertling at online.de
>>>>> wrote:
>>>>>
>>>>>> On 03/03/2012 10:36 PM, Ajay Panyala wrote:
>>>>>>> Try "cmake -E copy_if_different ..."
>>>>>>>
>>>>>>> cmake -E copy_if_different build/test1.c build/tests/test1.c
>>>>>>>
>>>>>>> That would work when make is run atleast once.
>>>>>>> When running make for the 1st time test1.c was never
>>>>>>> copied to build/tests before. So I would be comparing a file with
>>>>>>> another non-existant file and that would result in an error halting
>>>>>>> the make process.
>>>>>>
>>>>>> No, it wouldn't; check it out:
>>>>>>
>>>>>> % touch a
>>>>>> % rm -f b
>>>>>> % ls b
>>>>>> ls: cannot access b: No such file or directory
>>>>>> % cmake -E copy_if_different a b
>>>>>> % ls b
>>>>>> b
>>>>>> % cksum a b
>>>>>> 4294967295 0 a
>>>>>> 4294967295 0 b
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>> Michael
>>>>>>
>>>>>>> On Sat, Mar 3, 2012 at 1:20 PM, Hendrik Sattler <
>>>> post at hendrik-sattler.de
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Am Samstag, 3. März 2012, 21:41:49 schrieb Ajay Panyala:
>>>>>>>>> I have a custom target which runs a command to generate
>>>>>>>>> a C source file say test1.c
>>>>>>>>>
>>>>>>>>> ADD_CUSTOM_TARGET(TestGen ALL
>>>>>>>>> COMMAND genExec ${PROJECT_SOURCE_DIR}/Main.java
>>>>>>>>> DEPENDS ${PROJECT_SOURCE_DIR}/Main.java
>>>>>>>>> )
>>>>>>>>>
>>>>>>>>> And I have a custom command that moves the generated *test1.c *
>>>>>>>>> to a new directory inside the build directory.
>>>>>>>>>
>>>>>>>>> ADD_CUSTOM_COMMAND(
>>>>>>>>> TARGET TestGen
>>>>>>>>> POST_BUILD
>>>>>>>>> COMMAND mv
>>>>>>>>> ARGS ${PROJECT_BINARY_DIR}/test1.c ${PROJECT_BINARY_DIR}/tests/
>>>>>>>>> )
>>>>>>>>>
>>>>>>>>> Each time I run make, the custom target is run (since custom
>> targets
>>>>>> are
>>>>>>>>> always
>>>>>>>>> out-of-date). But I want to avoid moving the new test1.c generated
>>>> each
>>>>>>>>> time if build/test1.c is the same as build/tests/test1.c since
>> there
>>>>>> are
>>>>>>>>> other targets
>>>>>>>>> like add_executable and add_library later in the CMakelists file
>> that
>>>>>> are
>>>>>>>>> re-built
>>>>>>>>> each time since they depend on test1.c
>>>>>>>>
>>>>>>>> Try "cmake -E copy_if_different ..."
>>>>>>>>
>>>>>>>> HS
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