fix: set correct argc=0 in _start() function

[luoliwoshang]

The original code used icmp eq i32 0, 0 which always evaluates to true, resulting in argc=1:

 declare i32 @printf(i8*, ...)
  @fmt = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1

  define i32 @main() {
  entry:
    %argc_val = icmp eq i32 0, 0
    %argc = zext i1 %argc_val to i32
    %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @fmt, i64 0, i64 0), i32 %argc)
    ret i32 0
  }

Output: 1 (incorrect)

After fix with add i32 0, 0, argc correctly equals 0.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.94%. Comparing base (f43e2c0) to head (b9fdc2a).
⚠️ Report is 19 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1211   +/-   ##
=======================================
  Coverage   87.93%   87.94%           
=======================================
  Files          32       32           
  Lines        7653     7657    +4     
=======================================
+ Hits         6730     6734    +4     
  Misses        844      844           
  Partials       79       79           

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[cpunion]

Fixing argv instead of argc. argc should be greater than or equal to 1, and argv[0] should be the executable path.

[luoliwoshang]

argc should be greater than or equal to 1, and argv[0] should be the executable path.

I found a few challenges:

1. Executable path cannot be determined at compile time
2. LLVM cannot dynamically retrieve this path - it maybe requires OS-specific syscalls

So i think the most reasonable solution might be setting argc = 1 and argv[0] to an empty string to at least comply with the C standard minimum requirements, rather than the current argc = 0, argv = null.

[cpunion]

I found a few challenges:

1. Executable path cannot be determined at compile time
2. LLVM cannot dynamically retrieve this path - it maybe requires OS-specific syscalls

So i think the most reasonable solution might be setting argc = 1 and argv[0] to an empty string to at least comply with the C standard minimum requirements, rather than the current argc = 0, argv = null.

I agree with your solution.