[BUG] global variable initialized from num_performance_cores() become 0 after compile

[SynodicMonth]

Bug description

from sys.info import num_performance_cores
var workers = num_performance_cores()

def main():
    print(workers)

Using mojo run, it works normally and prints 6.
After mojo compile, it prints 0.

Steps to reproduce

just run the code above.

btw,

from sys.info import num_performance_cores

def main():
    print(num_performance_cores())

This works well in both mojo run and mojo compile.

System information

- Ubuntu 22.04.4 LTS
- mojo 24.4.0 (2cb57382)
- modular 0.8.0 (39a426b5)

[DWSimmons]

Appears it's not just cores, it's all of sys.info(?!)*

Confirmed same behavior on mojo 2024.7.2521 (a7cec710) and ubuntu 22.04.4

*Tested 5 of the sys.info calls

from sys.info import *

var workers = num_performance_cores()
var logical = num_logical_cores()
var physical = num_physical_cores()

var SIMD_BIT_WIDTH = simdbitwidth()
var SIMDBITEWIDTH = simdbytewidth()


def main():
    print(workers)
    print(logical)
    print(physical)
    print(SIMD_BIT_WIDTH)
    print(SIMDBITEWIDTH)

Returns

darin@home:~/Playground/mojo_bug_testing$ mojo 3311_test_extra.mojo
8
16
8
256
32
darin@home:~/Playground/mojo_bug_testing$ mojo build 3311_test_extra.mojo
darin@home:~/Playground/mojo_bug_testing$ ./3311_test_extra 
0
0
0
0
0

[DWSimmons]

Aliasing all the above calls does not compile

from sys.info import *

alias workers = num_performance_cores()
alias logical = num_logical_cores()
alias physical = num_physical_cores()

alias SIMD_BIT_WIDTH = simdbitwidth()
alias SIMDBITEWIDTH = simdbytewidth()


def main():
    print(workers)
    print(logical)
    print(physical)
    print(SIMD_BIT_WIDTH)
    print(SIMDBITEWIDTH)

returns

/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:113:4: error: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:96:4: note: function instantiation failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:108:57: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:68:4: note: function instantiation failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:84:18: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:105:8: note: function instantiation failed
<unknown>:0: note: failed to compile-time evaluate function call
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:709:4: note: failed to interpret function @stdlib::sys::info::num_performance_cores()
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:716:76: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/ffi.mojo:342:6: note: failed to interpret operation pop.external_call{func: "KGEN_CompilerRT_NumPerformanceCores" : !kgen.string, funcAttrs: ["willreturn"], memory: #llvm.memory_effects<other = none, argMem = none, inaccessibleMem = none>, resAttrs: [{llvm.noundef}]}(#kgen.pack<> : !kgen.pack<[]>)
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:716:76: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/ffi.mojo:342:6: note: unable to interpret call to unknown external function: KGEN_CompilerRT_NumPerformanceCores
mojo: error: failed to run the pass manager

[jackos]

I can't reproduce this on the current internal build. If you move var workers = num_performance_cores() into def main like:

from sys.info import num_performance_cores

def main():
    var workers = num_performance_cores()
    print(workers)

Does that fix it?

@abduld is a global var statement undefined behavior at the moment?

[DWSimmons]

I can't reproduce this on the current internal build. If you move var workers = num_performance_cores() into def main like:

from sys.info import num_performance_cores

def main():
    var workers = num_performance_cores()
    print(workers)

Does that fix it?

@abduld is a global var statement undefined behavior at the moment?

Yes, var in scope of main works.

alias workers in global throws an error on print for variadic statements [expected?]
alias workers in def main returns

/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:113:4: error: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:96:4: note: function instantiation failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:108:57: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:68:4: note: function instantiation failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:84:18: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/builtin/_startup.mojo:105:8: note: function instantiation failed
<unknown>:0: note: failed to compile-time evaluate function call
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:709:4: note: failed to interpret function @stdlib::sys::info::num_performance_cores()
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:716:76: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/ffi.mojo:342:6: note: failed to interpret operation pop.external_call{func: "KGEN_CompilerRT_NumPerformanceCores" : !kgen.string, funcAttrs: ["willreturn"], memory: #llvm.memory_effects<other = none, argMem = none, inaccessibleMem = none>, resAttrs: [{llvm.noundef}]}(#kgen.pack<> : !kgen.pack<[]>)
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/info.mojo:716:76: note: call expansion failed
/__w/modular/modular/open-source/mojo/stdlib/stdlib/sys/ffi.mojo:342:6: note: unable to interpret call to unknown external function: KGEN_CompilerRT_NumPerformanceCores
mojo: error: failed to run the pass manager

[jackos]

alias workers in global throws an error on print for variadic statements [expected?]

No that is unexpected and we should fix it