Diffusion Ant (type-hints-typescript) Code

ant/tests/bench_jit_deopt.js
899dad6b8a9etype-hints-typescript

bench_jit_deopt.js
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			// Benchmark: JIT deoptimization & recompilation
			//
			// Scenarios:
			// 1. Single bailout → recompile → regain JIT speed
			// 2. Repeated bailouts → permanent ban
			// 3. No bailout baseline (pure numeric hot loop)
			// 4. Periodic type instability across rounds
			// 5. Correctness across all JIT states
			// 6. Multi-op arithmetic chain (ADD/SUB/MUL/DIV) bailout recovery
			// 7. Large hot loop — JIT vs interpreter throughput
			// 8. Rapid-fire bailouts (many in quick succession)
			// 9. Comparison operators bailout recovery
			// 10. Closure with upvalue — bailout and recovery

			var get_clock = typeof performance !== 'undefined' ? performance.now : Date.now;
			var JIT_THRESHOLD = 100;
			var RECOMPILE_DELAY = 50;
			var ITER = 500000;

			function timeit(fn, label) {
			var best = Infinity;
			for (var t = 0; t < 3; t++) {
			var t0 = get_clock();
			var result = fn();
			var elapsed = get_clock() - t0;
			if (elapsed < best) best = elapsed;
			}
			console.log(' ' + label + ': ' + best.toFixed(2) + ' ms');
			return best;
			}

			function warmup(fn, n) {
			for (var i = 0; i < (n \|\| JIT_THRESHOLD + 10); i++) fn(i, i + 1);
			}

			// ============================================================
			// Scenario 1: Single bailout then recompile
			// ============================================================
			console.log('--- S1: single bailout + recompile ---');

			function addS1(a, b) { return a + b; }
			warmup(addS1);

			var s1_before = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addS1(s, 1);
			return s;
			}, 'before bailout');

			addS1('bail', 'out');
			warmup(addS1, RECOMPILE_DELAY + 10);

			var s1_after = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addS1(s, 1);
			return s;
			}, 'after recompile');

			// ============================================================
			// Scenario 2: Exhaust deopts → permanent ban
			// ============================================================
			console.log('');
			console.log('--- S2: permanent ban ---');

			function addS2(a, b) { return a + b; }

			for (var deopt = 0; deopt < 4; deopt++) {
			warmup(addS2);
			addS2('x' + deopt, 'y');
			warmup(addS2, RECOMPILE_DELAY + 10);
			}
			// should be banned now regardless of strategy
			for (var i = 0; i < JIT_THRESHOLD * 3; i++) addS2(i, i + 1);

			var s2 = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addS2(s, 1);
			return s;
			}, 'banned (interpreter)');

			// ============================================================
			// Scenario 3: Pure numeric baseline
			// ============================================================
			console.log('');
			console.log('--- S3: pure numeric baseline ---');

			function addS3(a, b) { return a + b; }
			warmup(addS3);

			var s3 = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addS3(s, 1);
			return s;
			}, 'JIT baseline');

			// ============================================================
			// Scenario 4: Periodic type instability
			// ============================================================
			console.log('');
			console.log('--- S4: periodic type instability ---');

			function addS4(a, b) { return a + b; }

			var s4_times = [];
			for (var round = 0; round < 8; round++) {
			warmup(addS4);
			var t = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addS4(s, 1);
			return s;
			}, 'round ' + round);
			s4_times.push(t);
			addS4('round', String(round));
			warmup(addS4, RECOMPILE_DELAY + 10);
			}

			// ============================================================
			// Scenario 5: Correctness across all JIT states
			// ============================================================
			console.log('');
			console.log('--- S5: correctness ---');

			function compute(a, b) { return a + b; }
			var allCorrect = true;

			warmup(compute);
			if (compute(20, 22) !== 42) { allCorrect = false; console.log(' FAIL: numeric JIT'); }
			if (compute('hello', ' world') !== 'hello world') { allCorrect = false; console.log(' FAIL: string bailout'); }
			if (compute(100, -58) !== 42) { allCorrect = false; console.log(' FAIL: numeric post-bailout'); }
			warmup(compute, RECOMPILE_DELAY + 10);
			if (compute(20, 22) !== 42) { allCorrect = false; console.log(' FAIL: numeric recompile'); }
			if (compute('foo', 'bar') !== 'foobar') { allCorrect = false; console.log(' FAIL: string bailout 2'); }
			warmup(compute, RECOMPILE_DELAY + 10);
			if (compute(1, 1) !== 2) { allCorrect = false; console.log(' FAIL: numeric recompile 2'); }
			if (compute('a', 'b') !== 'ab') { allCorrect = false; console.log(' FAIL: string bailout 3'); }
			for (var i = 0; i < 500; i++) compute(i, 1);
			if (compute(20, 22) !== 42) { allCorrect = false; console.log(' FAIL: numeric after ban'); }
			console.log(' all correct: ' + allCorrect);

			// ============================================================
			// Scenario 6: Multi-op arithmetic chain — bailout recovery
			// ============================================================
			console.log('');
			console.log('--- S6: arithmetic chain bailout ---');

			function mathChain(a, b, c) {
			var x = a + b;
			var y = x * c;
			var z = y - a;
			return z / b;
			}

			for (var i = 1; i < JIT_THRESHOLD + 10; i++) mathChain(i, i + 1, 2);

			var s6_before = timeit(function() {
			var s = 0;
			for (var i = 1; i <= ITER; i++) s = mathChain(i, i + 1, 2);
			return s;
			}, 'chain before bailout');

			// bailout: string in numeric chain triggers coercion
			mathChain('10', 5, 3);

			for (var i = 1; i < RECOMPILE_DELAY + 10; i++) mathChain(i, i + 1, 2);

			var s6_after = timeit(function() {
			var s = 0;
			for (var i = 1; i <= ITER; i++) s = mathChain(i, i + 1, 2);
			return s;
			}, 'chain after recompile');

			// ============================================================
			// Scenario 7: Large hot loop — throughput comparison
			// ============================================================
			console.log('');
			console.log('--- S7: large hot loop throughput ---');

			function hotSum(n) {
			var sum = 0;
			for (var i = 0; i < n; i++) sum = sum + i;
			return sum;
			}

			warmup(function(i) { hotSum(10); return i; });

			var s7_jit = timeit(function() { return hotSum(1000000); }, 'JIT 1M loop');

			// bailout
			hotSum('not a number');
			warmup(function(i) { hotSum(10); return i; }, RECOMPILE_DELAY + 10);

			var s7_recover = timeit(function() { return hotSum(1000000); }, 'after bailout 1M');

			// ============================================================
			// Scenario 8: Rapid-fire bailouts
			// ============================================================
			console.log('');
			console.log('--- S8: rapid-fire bailouts ---');

			function addRapid(a, b) { return a + b; }

			warmup(addRapid);

			// fire 10 bailouts in quick succession, re-warming each time
			for (var k = 0; k < 10; k++) {
			addRapid('rapid' + k, '!');
			warmup(addRapid, RECOMPILE_DELAY + 10);
			}

			var s8 = timeit(function() {
			var s = 0;
			for (var i = 0; i < ITER; i++) s = addRapid(s, 1);
			return s;
			}, 'after 10 rapid bailouts');

			// ============================================================
			// Scenario 9: Comparison operators
			// ============================================================
			console.log('');
			console.log('--- S9: comparison bailout ---');

			function ltCmp(a, b) { return a < b; }

			for (var i = 0; i < JIT_THRESHOLD + 10; i++) ltCmp(i, 100);

			var s9_before = timeit(function() {
			var c = 0;
			for (var i = 0; i < ITER; i++) { if (ltCmp(i, ITER / 2)) c++; }
			return c;
			}, 'LT before bailout');

			ltCmp('abc', 'def');
			for (var i = 0; i < RECOMPILE_DELAY + 10; i++) ltCmp(i, 100);

			var s9_after = timeit(function() {
			var c = 0;
			for (var i = 0; i < ITER; i++) { if (ltCmp(i, ITER / 2)) c++; }
			return c;
			}, 'LT after recompile');

			// ============================================================
			// Scenario 10: Closure with upvalue
			// ============================================================
			console.log('');
			console.log('--- S10: closure upvalue bailout ---');

			function makeAccum(init) {
			var total = init;
			return function(v) { total = total + v; return total; };
			}

			var accum = makeAccum(0);
			for (var i = 0; i < JIT_THRESHOLD + 10; i++) accum(1);

			var s10_before = timeit(function() {
			var a = makeAccum(0);
			for (var i = 0; i < JIT_THRESHOLD + 10; i++) a(1); // re-JIT the inner fn
			for (var i = 0; i < ITER; i++) a(1);
			return a(0);
			}, 'closure before bailout');

			// bailout: string into numeric accumulator
			var accum2 = makeAccum(0);
			for (var i = 0; i < JIT_THRESHOLD + 10; i++) accum2(1);
			accum2(' world');
			for (var i = 0; i < RECOMPILE_DELAY + 10; i++) accum2(1);

			var s10_after = timeit(function() {
			var a = makeAccum(0);
			for (var i = 0; i < JIT_THRESHOLD + 10; i++) a(1);
			for (var i = 0; i < ITER; i++) a(1);
			return a(0);
			}, 'closure after recompile');

			// ============================================================
			// Summary
			// ============================================================
			console.log('');
			console.log('=== SUMMARY ===');
			console.log(' S1 recovery: ' + (s1_after / s1_before * 100).toFixed(0) + '% of JIT speed');
			console.log(' S3 baseline: ' + s3.toFixed(2) + ' ms');
			console.log(' S2 banned: ' + s2.toFixed(2) + ' ms (' + (s2 / s3).toFixed(1) + 'x slower than JIT)');
			console.log(' S6 chain recovery: ' + (s6_after / s6_before * 100).toFixed(0) + '%');
			console.log(' S7 loop recovery: ' + (s7_recover / s7_jit * 100).toFixed(0) + '%');
			console.log(' S9 cmp recovery: ' + (s9_after / s9_before * 100).toFixed(0) + '%');
			console.log(' S5 correctness: ' + allCorrect);

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