nx_emptylit_probe.nx source

1// nx_emptylit_probe.nx -- MEASURE the empty-string-literal defect instead of asserting its scope. 2// A grep found 3137 uses of `"" as *u8` in runtime/. Before filing that as an estate-wide landmine I have 3// to know WHICH shapes are actually broken, because "3137 sites are wrong" and "one shape is wrong" are 4// very different findings and only one of them is true. 5// license_tier: ORIGINAL expect_exit: 0 6import "nx_syscalls.nx" 7 8func w(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 } 9func n_(v: i64) -> i64 { 10 let bb: *u8=sys_mmap(28); var m: i64=v 11 if m<0 { m=0-m; sys_write(1,"-" as *u8,1) } 12 let t: *u8=sys_mmap(28); var k: i64=0 13 if m==0 { t[0]=48 as u8; k=1 } 14 while m>0 { t[k]=(48+(m%10)) as u8; m=m/10; k=k+1 } 15 var i: i64=0 16 while i<k { bb[i]=t[k-1-i]; i=i+1 } 17 sys_write(1,bb,k); return 0 18} 19func sl(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} return n } 20 21// SHAPE A: multi-branch function returning an empty literal first, a non-empty one after. This is the 22// shape that actually bit the ruler. 23func shape_a(i: i64) -> *u8 { 24 if i==0 { return "" as *u8 } 25 if i==1 { return "runtime/" as *u8 } 26 return "buildroot/" as *u8 27} 28// SHAPE B: same, but the empty literal is the LAST return 29func shape_b(i: i64) -> *u8 { 30 if i==1 { return "runtime/" as *u8 } 31 return "" as *u8 32} 33// SHAPE C: empty literal returned by a function with no other literal at all 34func shape_c() -> *u8 { return "" as *u8 } 35 36func main() -> i64 { 37 w("--- shape A: empty literal is the FIRST of several returns ---\n" as *u8) 38 w(" A(0) len=" as *u8); n_(sl(shape_a(0))); w(" bytes=[" as *u8); w(shape_a(0)); w("]\n" as *u8) 39 w(" A(1) len=" as *u8); n_(sl(shape_a(1))); w(" bytes=[" as *u8); w(shape_a(1)); w("]\n" as *u8) 40 41 w("--- shape B: empty literal is the LAST return ---\n" as *u8) 42 w(" B(0) len=" as *u8); n_(sl(shape_b(0))); w(" bytes=[" as *u8); w(shape_b(0)); w("]\n" as *u8) 43 44 w("--- shape C: empty literal is the ONLY literal in the function ---\n" as *u8) 45 w(" C() len=" as *u8); n_(sl(shape_c())); w(" bytes=[" as *u8); w(shape_c()); w("]\n" as *u8) 46 47 w("--- shape D: empty literal bound to a local, next to another literal ---\n" as *u8) 48 let e: *u8 = "" as *u8 49 let f: *u8 = "runtime/" as *u8 50 w(" D len=" as *u8); n_(sl(e)); w(" bytes=[" as *u8); w(e); w("] (f=[" as *u8); w(f); w("])\n" as *u8) 51 52 w("--- shape E: empty literal passed straight as an argument ---\n" as *u8) 53 w(" E len=" as *u8); n_(sl("" as *u8)); w(" bytes=[" as *u8); w("" as *u8); w("]\n" as *u8) 54 55 w("--- shape F: comparing an empty literal to itself ---\n" as *u8) 56 let g1: *u8 = "" as *u8 57 var same: i64 = 0 58 if g1[0]==(0 as u8) { same = 1 } 59 w(" F first byte is NUL = " as *u8); n_(same); w("\n" as *u8) 60 sys_exit(0) 61 return 0 62}