nx_js_feedback_gate.nx source

1// nx_js_feedback_gate.nx -- P6 rung 1: TYPE FEEDBACK (Maglev's "runtime metadata collected during 2// unoptimized execution"). Proves the interpreter correctly classifies each BINOP site as INT-monomorphic 3// (safe for the optimizing tier to speculate unboxed i64) vs polymorphic. OPT-IN (js_fb_enable) = zero 4// baseline overhead. This is the substrate the CFG-SSA optimizing tier consumes. [[reference-js-optimizing-jit-sota-2026-07-08]] 5// expect_exit: 0 license_tier: ORIGINAL 6import "nx_js_vm.nx" 7func fw(s: *u8) -> i64 { var n: i64 = 0; while s[n] != (0 as u8) { n = n + 1 } sys_write(1, s, n); return 0 } 8func fn(v: i64) -> i64 { if v==0 { sys_write(1,"0" as *u8,1); return 0 } var m: i64=v; if m<0 { sys_write(1,"-" as *u8,1); m=0-m } let t: *u8=sys_mmap(24); var k: i64=0; while m>0 { t[k]=(48+(m%10)) as u8; m=m/10; k=k+1 } let o: *u8=sys_mmap(24); var q: i64=k-1; var x: i64=0; while q>=0 { o[x]=t[q]; x=x+1; q=q-1 } sys_write(1,o,x); return 0 } 9 10func main(argc: i64, argv: *i64) -> i64 { 11 fw("=== nx_js_feedback_gate: P6 rung 1 -- type feedback (int-mono vs poly BINOP sites) ===\n" as *u8) 12 let out: *i64 = sys_mmap(16) as *i64 13 var pass: i64 = 0 14 var tot: i64 = 0 15 js_jit_disable(1) // force the INTERPRETER so feedback is collected (Maglev collects in the low tier) 16 17 // A) all-integer kernel: every BINOP site (+ - * <) sees int+int -> ALL should be INT-monomorphic, ZERO poly. 18 js_fb_enable(1) 19 compile_run("var s=0;var i=0;while(i<50){s=s+i*3-i;i=i+1;}s" as *u8, out) 20 let intA: i64 = js_fb_count(1) 21 let polyA: i64 = js_fb_count(2) 22 fw(" A all-int loop: int-mono sites=") 23 fn(intA) 24 fw(" poly sites=") 25 fn(polyA) 26 fw(" (result ") 27 fn(out[1]) 28 fw(")\n") 29 tot = tot + 1 30 if intA > 0 { if polyA == 0 { pass = pass + 1; fw(" -> ok (all sites int-monomorphic, none poly)\n" as *u8) } else { fw(" -> FAIL (unexpected poly)\n" as *u8) } } else { fw(" -> FAIL (no int-mono sites recorded)\n" as *u8) } 31 32 // B) mixed int/float kernel: i*1.5 and s+float -> those sites MUST be classified polymorphic. 33 js_fb_enable(1) 34 compile_run("var s=0;var i=0;while(i<50){s=s+i*1.5;i=i+1;}s" as *u8, out) 35 let intB: i64 = js_fb_count(1) 36 let polyB: i64 = js_fb_count(2) 37 fw(" B mixed int/float loop: int-mono sites=") 38 fn(intB) 39 fw(" poly sites=") 40 fn(polyB) 41 fw("\n") 42 tot = tot + 1 43 if polyB > 0 { pass = pass + 1; fw(" -> ok (float-tainted sites correctly polymorphic)\n" as *u8) } else { fw(" -> FAIL (float site not flagged poly)\n" as *u8) } 44 45 // C) feedback OFF by default = zero recording (no overhead in production). 46 js_fb_enable(0) 47 js_jit_disable(0) 48 tot = tot + 1 49 // re-enable+reset, run nothing, expect all cold 50 js_fb_enable(1) 51 let coldC: i64 = js_fb_count(1) + js_fb_count(2) 52 js_fb_enable(0) 53 if coldC == 0 { pass = pass + 1; fw(" C reset clears the table (opt-in, zero baseline overhead): ok\n" as *u8) } else { fw(" C FAIL (stale feedback)\n" as *u8) } 54 55 fw(" --- ") 56 fn(pass) 57 fw("/") 58 fn(tot) 59 fw(" ---\n" as *u8) 60 if pass == tot { 61 fw("=== GREEN: type-feedback substrate works -- int-mono sites separable from poly (P6 rung 1) ===\n" as *u8) 62 return 0 63 } 64 fw("=== RED ===\n" as *u8) 65 return 1 66}