be/c: use temporary file for emitting c-code

[michaellilltokiwa]

PR due to @maxteufel suggestion from here: #2574 (review)

example output:

/home/not_synced/fuzion (2024-02-23T11-51-27+01-00)$ fz -verbose=1 -c tests/hello/HelloWorld.fz 

warning 1: New clazz created during layout phase: (list u8).as_array.#fun1.call


warning 2: New clazz created during layout phase: (list u8).as_stream.as_stream


warning 3: New clazz created during layout phase: (list u8).as_array.lm.#fun52.call


warning 4: New clazz created during layout phase: ((list u8).as_array.lm.go (array u8)).#fun2.call

 + /tmp/fuzion-3219614508357886221.c
 * clang -Wall -Werror -Wno-trigraphs -Wno-gnu-empty-struct -Wno-unused-variable -Wno-unused-label -Wno-unused-function -Wno-infinite-recursion -Wno-unused-but-set-variable -O3 -lgc -DGC_THREADS -DGC_PTHREADS -DPTW32_STATIC_LIB -DGC_WIN32_PTHREADS -fno-trigraphs -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -std=c11 -o HelloWorld /home/not_synced/fuzion/build/include/shared.c /home/not_synced/fuzion/build/include/posix.c /tmp/fuzion-3219614508357886221.c
Elapsed time for phases: prep 31ms, fe 75ms, createMIR 1ms, me 68ms, ir 645ms, effectsCheck 132ms, be 1234ms
4 warnings.

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[fridis]

It is much nicer not dumping temporary files into the current directory.

I think these temp files are not deleted automatically, so this will result in lots of temp files with ending up in /tmp. But when they are automatically deleted, we will need some option for the fz command to keep them for our debugging.

Also, I think it would be better to include the main feature name just to make this a little less confusion, i..e, create /tmp/fuzion-helloworld-3219614508357886221.c.

[michaellilltokiwa]

I think these temp files are not deleted automatically, so this will result in lots of temp files with ending up in /tmp. But when they are automatically deleted, we will need some option for the fz command to keep them for our debugging.

My understanding is that the OS is responsible to delete these files after a while. For example when rebooting.

[maxteufel]

My understanding is that the OS is responsible to delete these files after a while.

The OS can delete them after a while, but likely we will do ourselves a favor if we remove the files unless an option is set to keep the files. You don't want to try every one of them if you're debugging something.

[michaellilltokiwa]

@maxteufel I added an option -XkeepGeneratedCode as suggested. Also temporary c-file gets deleted when java exists.

[maxteufel]

I expected this to simply keep the files in /tmp but this works too.

[maxteufel]

is that done without precompiling the library?

[michaellilltokiwa]

Currently yes, see issue #2589

[maxteufel]

no i mean this comment shouldn't be removed then since the task is not done yet.

[maxteufel]

do not forget to change this in flang.dev, too