No local variable name info with -g4 in Emscripten 1.37.0

[xiyanggudao]

After upgrade Emscripten from 1.35 to 1.37, the JS code generate by -g4 has no local variable name info, it looks like they were minimized when compiled to BC. Is there any method to keep these info?
Thanks.

[kripken]

That's surprising, do you have a testcase showing the issue?

[xiyanggudao]

I use the llvm-dis to transform bc to assembler, and find the local variable name info has lost. So I guess it is because the upgrade of llvm.

A a testcase hello_world.cpp
#include <stdio.h>
int main() {
int local_val;
scanf("%d", &local_val);
printf("hello, world! %d\n", local_val);
return 0;
}

compile command
emcc hello_world.cpp -o hello_world.js -g4

The javascript code. local variable “local_val” was transformed with "$2"
function _main() {
var $0 = 0, $1 = 0, $2 = 0, $vararg_buffer = 0, $vararg_buffer1 = 0, label = 0, sp = 0;
sp = STACKTOP;
STACKTOP = STACKTOP + 32|0; if ((STACKTOP|0) >= (STACK_MAX|0)) abortStackOverflow(32|0);
$vararg_buffer1 = sp + 8|0;
$vararg_buffer = sp;
$1 = sp + 12|0;
$0 = 0;
HEAP32[$vararg_buffer>>2] = $1; //@line 7 "hello_world.cpp"
(_scanf(488,$vararg_buffer)|0); //@line 7 "hello_world.cpp"
$2 = HEAP32[$1>>2]|0; //@line 8 "hello_world.cpp"
HEAP32[$vararg_buffer1>>2] = $2; //@line 8 "hello_world.cpp"
(_printf(491,$vararg_buffer1)|0); //@line 8 "hello_world.cpp"
STACKTOP = sp;return 0; //@line 9 "hello_world.cpp"
}

[kripken]

LLVM updates can change that, but on latest incoming (1.37.9), I see this output:

function _main() {
 var $0 = 0, $local_val = 0, $retval = 0, $vararg_buffer = 0, $vararg_buffer1 = 0, label = 0, sp = 0;
 sp = STACKTOP;
 STACKTOP = STACKTOP + 32|0; if ((STACKTOP|0) >= (STACK_MAX|0)) abortStackOverflow(32|0);
 $vararg_buffer1 = sp + 8|0;
 $vararg_buffer = sp;
 $local_val = sp + 12|0;
 $retval = 0;
 HEAP32[$vararg_buffer>>2] = $local_val; //@line 4 "a.cpp"
 (_scanf(756,$vararg_buffer)|0); //@line 4 "a.cpp"
 $0 = HEAP32[$local_val>>2]|0; //@line 5 "a.cpp"
 HEAP32[$vararg_buffer1>>2] = $0; //@line 5 "a.cpp"
 (_printf(759,$vararg_buffer1)|0); //@line 5 "a.cpp"
 STACKTOP = sp;return 0; //@line 6 "a.cpp"
}

Looks like local_val is there, so perhaps the last LLVM update changed things again.

[xiyanggudao]

OK, thanks