Fix panic in regex execution

[0x7D2B]

This Pull Request fixes #1242, though that one might be accidentally triggering a different panic that's fixed in #1280

[0x7D2B]

The spec actually wants ToLength and not ToIndex for lastIndex. Makes sense, right?

[github-actions]

Test262 conformance changes:

Test result	master count	PR count	difference
Total	78,873	78,873	0
Passed	26,622	26,628	+6
Ignored	15,604	15,604	0
Failed	36,647	36,641	-6
Panics	22	22	0
Conformance	33.75%	33.76%	+0.01%

[github-actions]

Benchmark for 62f67b5

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Arithmetic operations (Execution)	310.8±0.16ns	302.2±0.15ns	+2.85%
Arithmetic operations (Full)	225.1±4.34µs	228.2±0.26µs	-1.36%
Array access (Execution)	5.2±0.02µs	5.3±0.02µs	-1.89%
Array access (Full)	248.7±0.30µs	254.4±0.66µs	-2.24%
Array creation (Execution)	2.4±0.00ms	2.4±0.01ms	0.00%
Array creation (Full)	2.8±0.02ms	2.8±0.00ms	0.00%
Array pop (Execution)	779.9±1.51µs	780.4±2.24µs	-0.06%
Array pop (Full)	1204.6±6.83µs	1199.2±1.29µs	+0.45%
Boolean Object Access (Execution)	4.5±0.01µs	4.5±0.00µs	0.00%
Boolean Object Access (Full)	242.7±5.72µs	249.8±0.44µs	-2.84%
Clean js (Execution)	551.6±3.10µs	558.2±5.00µs	-1.18%
Clean js (Full)	829.9±2.73µs	827.3±3.54µs	+0.31%
Clean js (Parser)	36.3±0.06µs	36.5±0.07µs	-0.55%
Create Realm	360.3±0.54ns	351.6±2.73ns	+2.47%
Dynamic Object Property Access (Execution)	4.2±0.01µs	4.3±0.00µs	-2.33%
Dynamic Object Property Access (Full)	245.7±1.30µs	249.6±0.36µs	-1.56%
Expression (Parser)	6.2±0.00µs	6.2±0.01µs	0.00%
Fibonacci (Execution)	641.9±1.45µs	642.5±1.94µs	-0.09%
Fibonacci (Full)	903.3±1.10µs	900.8±1.06µs	+0.28%
For loop (Execution)	18.4±0.16µs	18.5±0.05µs	-0.54%
For loop (Full)	257.2±3.32µs	259.9±0.32µs	-1.04%
For loop (Parser)	17.4±0.03µs	17.3±0.04µs	+0.58%
Goal Symbols (Parser)	12.2±0.04µs	12.2±0.02µs	0.00%
Hello World (Parser)	3.4±0.01µs	3.4±0.00µs	0.00%
Long file (Parser)	730.1±9.18ns	723.7±9.59ns	+0.88%
Mini js (Execution)	496.7±2.54µs	500.4±2.68µs	-0.74%
Mini js (Full)	771.1±3.54µs	771.2±2.39µs	-0.01%
Mini js (Parser)	31.7±0.30µs	31.7±0.50µs	0.00%
Number Object Access (Execution)	3.5±0.14µs	3.4±0.00µs	+2.94%
Number Object Access (Full)	237.6±0.29µs	244.8±0.64µs	-2.94%
Object Creation (Execution)	3.7±0.01µs	3.6±0.01µs	+2.78%
Object Creation (Full)	241.2±0.30µs	246.1±0.39µs	-1.99%
RegExp (Execution)	10.0±0.02µs	10.0±0.02µs	0.00%
RegExp (Full)	254.8±0.36µs	258.9±0.38µs	-1.58%
RegExp Literal (Execution)	10.0±0.02µs	10.0±0.02µs	0.00%
RegExp Literal (Full)	250.2±1.18µs	260.5±0.64µs	-3.95%
RegExp Literal Creation (Execution)	8.7±0.02µs	8.8±0.03µs	-1.14%
RegExp Literal Creation (Full)	246.5±0.37µs	251.6±0.68µs	-2.03%
Static Object Property Access (Execution)	3.8±0.02µs	3.8±0.02µs	0.00%
Static Object Property Access (Full)	241.5±0.29µs	247.6±0.32µs	-2.46%
String Object Access (Execution)	6.2±0.03µs	6.0±0.03µs	+3.33%
String Object Access (Full)	246.7±0.29µs	256.3±0.25µs	-3.75%
String comparison (Execution)	5.5±0.02µs	5.5±0.02µs	0.00%
String comparison (Full)	243.2±0.51µs	253.0±0.69µs	-3.87%
String concatenation (Execution)	4.5±0.01µs	4.5±0.05µs	0.00%
String concatenation (Full)	235.8±0.21µs	244.5±0.32µs	-3.56%
String copy (Execution)	3.3±0.01µs	3.3±0.01µs	0.00%
String copy (Full)	231.1±0.22µs	241.9±0.46µs	-4.46%
Symbols (Execution)	2.8±0.01µs	2.8±0.03µs	0.00%
Symbols (Full)	226.9±0.47µs	235.4±0.39µs	-3.61%

[github-actions]

Benchmark for 0818193

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Arithmetic operations (Execution)	404.4±22.59ns	410.6±28.40ns	-1.51%
Arithmetic operations (Full)	330.8±21.31µs	320.7±11.62µs	+3.15%
Array access (Execution)	7.7±0.65µs	7.5±0.43µs	+2.67%
Array access (Full)	356.0±15.62µs	351.4±13.30µs	+1.31%
Array creation (Execution)	3.1±0.16ms	3.1±0.12ms	0.00%
Array creation (Full)	3.4±0.12ms	3.5±0.20ms	-2.86%
Array pop (Execution)	988.6±30.93µs	999.7±46.87µs	-1.11%
Array pop (Full)	1550.4±118.49µs	1535.9±61.04µs	+0.94%
Boolean Object Access (Execution)	6.1±0.28µs	6.1±0.32µs	0.00%
Boolean Object Access (Full)	345.4±20.59µs	337.9±9.90µs	+2.22%
Clean js (Execution)	750.5±24.12µs	738.8±21.92µs	+1.58%
Clean js (Full)	1101.4±48.42µs	1092.5±46.43µs	+0.81%
Clean js (Parser)	48.5±3.76µs	47.3±3.36µs	+2.54%
Create Realm	467.0±31.94ns	456.1±14.93ns	+2.39%
Dynamic Object Property Access (Execution)	6.1±0.27µs	6.3±0.48µs	-3.17%
Dynamic Object Property Access (Full)	348.7±15.92µs	346.8±16.95µs	+0.55%
Expression (Parser)	7.9±0.54µs	7.8±0.34µs	+1.28%
Fibonacci (Execution)	978.4±53.20µs	967.3±131.03µs	+1.15%
Fibonacci (Full)	1312.2±124.45µs	1295.0±78.40µs	+1.33%
For loop (Execution)	26.2±1.72µs	25.6±1.86µs	+2.34%
For loop (Full)	371.7±36.24µs	361.4±16.16µs	+2.85%
For loop (Parser)	23.0±0.95µs	22.7±0.72µs	+1.32%
Goal Symbols (Parser)	15.7±0.84µs	15.7±0.81µs	0.00%
Hello World (Parser)	4.4±0.29µs	4.4±0.17µs	0.00%
Long file (Parser)	864.4±46.79ns	843.1±27.93ns	+2.53%
Mini js (Execution)	668.1±36.11µs	668.1±29.75µs	0.00%
Mini js (Full)	1031.0±82.02µs	1014.7±35.62µs	+1.61%
Mini js (Parser)	41.4±2.47µs	40.5±1.46µs	+2.22%
Number Object Access (Execution)	4.8±0.23µs	4.8±0.32µs	0.00%
Number Object Access (Full)	344.0±17.40µs	334.4±10.51µs	+2.87%
Object Creation (Execution)	5.4±0.26µs	5.2±0.16µs	+3.85%
Object Creation (Full)	348.5±18.95µs	348.4±18.31µs	+0.03%
RegExp (Execution)	13.0±0.89µs	12.5±0.52µs	+4.00%
RegExp (Full)	359.5±10.68µs	353.6±11.56µs	+1.67%
RegExp Literal (Execution)	12.8±0.68µs	12.8±1.11µs	0.00%
RegExp Literal (Full)	361.0±20.41µs	354.3±16.30µs	+1.89%
RegExp Literal Creation (Execution)	11.2±0.57µs	11.2±0.58µs	0.00%
RegExp Literal Creation (Full)	351.1±17.08µs	350.1±19.06µs	+0.29%
Static Object Property Access (Execution)	5.5±0.22µs	5.5±0.28µs	0.00%
Static Object Property Access (Full)	346.7±19.33µs	346.0±20.51µs	+0.20%
String Object Access (Execution)	8.5±0.44µs	8.5±0.54µs	0.00%
String Object Access (Full)	357.9±25.02µs	348.8±29.89µs	+2.61%
String comparison (Execution)	7.6±0.36µs	7.7±0.36µs	-1.30%
String comparison (Full)	352.5±24.18µs	345.3±16.76µs	+2.09%
String concatenation (Execution)	6.2±0.29µs	6.2±0.30µs	0.00%
String concatenation (Full)	340.0±22.98µs	347.9±34.05µs	-2.27%
String copy (Execution)	4.7±0.19µs	4.9±0.66µs	-4.08%
String copy (Full)	334.6±16.10µs	329.7±19.72µs	+1.49%
Symbols (Execution)	4.0±0.28µs	4.0±0.29µs	0.00%
Symbols (Full)	326.8±13.26µs	322.1±20.82µs	+1.46%

[RageKnify]

If master is merged into this branch we should see the panic numbers go down, right?

[Razican]

If master is merged into this branch we should see the panic numbers go down, right?

I think this is the panic that happens only "sometimes".

[0x7D2B]

There's something non-deterministic, there was a panic that disappeared after I made a commit that only added comments. With #1280 it should fix both of the issues causing panics that I came across.

[0x7D2B]

Let's see what happens to the tests.

[0x7D2B]

Weird. I was getting a panic in regress before this.

[github-actions]

Benchmark for 96c7491

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Arithmetic operations (Execution)	353.0±10.41ns	359.3±4.10ns	-1.75%
Arithmetic operations (Full)	265.5±6.60µs	275.8±0.31µs	-3.73%
Array access (Execution)	5.9±0.23µs	6.1±0.09µs	-3.28%
Array access (Full)	284.2±9.84µs	297.8±1.68µs	-4.57%
Array creation (Execution)	2.9±0.12ms	3.0±0.06ms	-3.33%
Array creation (Full)	3.2±0.11ms	3.5±0.13ms	-8.57%
Array pop (Execution)	934.4±28.56µs	964.8±19.18µs	-3.15%
Array pop (Full)	1414.4±46.33µs	1367.1±55.01µs	+3.46%
Boolean Object Access (Execution)	4.9±0.19µs	4.9±0.18µs	0.00%
Boolean Object Access (Full)	290.7±1.08µs	290.1±8.10µs	+0.21%
Clean js (Execution)	614.5±25.06µs	662.7±7.02µs	-7.27%
Clean js (Full)	979.5±13.67µs	921.5±37.40µs	+6.29%
Clean js (Parser)	40.3±0.91µs	40.6±0.74µs	-0.74%
Create Realm	446.7±10.93ns	415.8±12.01ns	+7.43%
Dynamic Object Property Access (Execution)	4.9±0.11µs	5.1±0.07µs	-3.92%
Dynamic Object Property Access (Full)	287.2±5.96µs	295.7±4.75µs	-2.87%
Expression (Parser)	7.3±0.06µs	7.0±0.29µs	+4.29%
Fibonacci (Execution)	711.6±23.77µs	752.5±1.90µs	-5.44%
Fibonacci (Full)	1014.7±36.18µs	1003.8±41.47µs	+1.09%
For loop (Execution)	21.9±0.14µs	22.0±0.15µs	-0.45%
For loop (Full)	288.9±9.91µs	289.7±14.24µs	-0.28%
For loop (Parser)	19.7±0.15µs	18.7±0.68µs	+5.35%
Goal Symbols (Parser)	13.7±0.37µs	14.3±0.15µs	-4.20%
Hello World (Parser)	4.0±0.07µs	3.9±0.13µs	+2.56%
Long file (Parser)	773.4±12.04ns	755.7±28.50ns	+2.34%
Mini js (Execution)	569.8±23.55µs	591.7±16.61µs	-3.70%
Mini js (Full)	898.1±13.31µs	859.7±33.12µs	+4.47%
Mini js (Parser)	35.9±0.51µs	36.0±0.06µs	-0.28%
Number Object Access (Execution)	3.8±0.15µs	4.0±0.11µs	-5.00%
Number Object Access (Full)	278.1±6.55µs	271.2±10.75µs	+2.54%
Object Creation (Execution)	4.1±0.22µs	4.4±0.03µs	-6.82%
Object Creation (Full)	279.9±4.65µs	285.2±7.65µs	-1.86%
RegExp (Execution)	10.5±0.25µs	10.9±0.10µs	-3.67%
RegExp (Full)	298.6±4.37µs	288.6±11.36µs	+3.47%
RegExp Literal (Execution)	10.0±0.50µs	10.7±0.13µs	-6.54%
RegExp Literal (Full)	294.6±6.24µs	303.4±0.50µs	-2.90%
RegExp Literal Creation (Execution)	9.3±0.14µs	9.4±0.15µs	-1.06%
RegExp Literal Creation (Full)	278.1±10.07µs	298.2±0.87µs	-6.74%
Static Object Property Access (Execution)	4.6±0.07µs	4.6±0.05µs	0.00%
Static Object Property Access (Full)	277.8±8.76µs	283.1±6.21µs	-1.87%
String Object Access (Execution)	6.5±0.27µs	7.1±0.09µs	-8.45%
String Object Access (Full)	287.2±5.49µs	298.7±0.58µs	-3.85%
String comparison (Execution)	6.1±0.32µs	6.5±0.15µs	-6.15%
String comparison (Full)	283.5±6.73µs	294.7±0.46µs	-3.80%
String concatenation (Execution)	4.9±0.19µs	5.1±0.08µs	-3.92%
String concatenation (Full)	271.4±11.11µs	272.8±8.56µs	-0.51%
String copy (Execution)	4.0±0.03µs	3.9±0.09µs	+2.56%
String copy (Full)	273.2±8.84µs	279.1±7.97µs	-2.11%
Symbols (Execution)	3.1±0.13µs	3.3±0.04µs	-6.06%
Symbols (Full)	267.1±7.74µs	277.8±0.84µs	-3.85%