Commit Graph

417 Commits

Author SHA1 Message Date
Alex Lam S.L
711f88dcb4 scan assignment value in drop_unused() (#1578)
those were not optimised for `unused` before, which made it necessary for `reduce_vars` to have separate steps for `keep_fnames`

docs update by @kzc

closes #1577
2017-03-08 18:37:32 +08:00
Alex Lam S.L
c7cdcf06a6 fix function name eliminiation (#1576)
Function expression can be assigned to a variable and be given a name. Ensure function name is the reduced variable before clearing it out.

fixes #1573
fixes #1575
2017-03-08 12:39:57 +08:00
Alex Lam S.L
bd6dee52ab fix return from recursive IIFE (#1570)
`side-effects` did not account for IIFEs being able to reference itself thus making its return value potentially significant
2017-03-08 03:31:51 +08:00
Alex Lam S.L
8153b7bd8a transform function calls to IIFEs (#1560)
- expose function body to call sites for potential optimisations
- suppress substitution of variable used within `AST_Defun`
2017-03-07 15:37:52 +08:00
Alex Lam S.L
d787d70127 avoid substitution of global variables (#1557)
- unless `toplevel` is enabled
- global `const` works as before
2017-03-07 03:11:03 +08:00
kzc
3ac2421932 collapse_vars: do not replace a constant in loop condition or init (#1562) 2017-03-07 01:42:33 +08:00
Alex Lam S.L
067e5a5762 fixup for #1553 (#1555)
- `++a` is the one that is foldable
- transform `a++` into `++a` for better optimisation
2017-03-05 17:15:37 +08:00
Alex Lam S.L
35a849dc48 collapse assignment with adjacent subsequent usage (#1553)
- consolidate `cascade` optimisations
- support ++/-- postfixes
- remove redundant optimisation identified in #1460

fixes #368
2017-03-05 14:56:14 +08:00
Alex Lam S.L
b70591be1a handle variable declaration within catch blocks (#1546)
accounts for IE8- scoping
2017-03-05 13:13:44 +08:00
Alex Lam S.L
b33e7f88e6 improve unsafe on undefined (#1548)
`unsafe` turns undefined keyword into a variable of the same name if found, but that interferes with other related optimisations.

Keep track of such transformations to ensure zero information loss in the process.
2017-03-05 13:09:27 +08:00
Alex Lam S.L
1f0333e9f1 stay safe with constants in IE8- (#1547)
- `undefined` etc. can be redefined at top-level for IE8-, so disable related optimisations
- fixed `--support-ie8` catch mangle bug
2017-03-05 12:51:11 +08:00
Alex Lam S.L
78d1bb92d4 fix a corner case in #1530 (#1552) 2017-03-05 12:12:59 +08:00
kzc
ce54c9ccee disallow collapse_vars constant replacement in for-in statements (#1543) 2017-03-04 02:39:54 +08:00
Alex Lam S.L
07accd2fbb process code with implicit return statement (#1522)
Bookmarklet for instance implicitedly assumes a "completion value" without using `return`.
The `expression` option now supports such use cases.
Optimisations on IIFEs also enhanced.

fixes #354
fixes #543
fixes #625
fixes #628
fixes #640
closes #1293
2017-03-03 18:13:07 +08:00
Alex Lam S.L
18059cc94f compress numerical expressions (#1513)
safe operations
- `a === b` => `a == b`
- `a + -b`  => `a - b`
- `-a + b`  => `b - a`
- `a+ +b`   => `+b+a`

associative operations
(bit-wise operations are safe, otherwise `unsafe_math`)
- `a + (b + c)`       => `(a + b) + c`
- `(n + 2) + 3`       => `5 + n`
- `(2 * n) * 3`       => `6 * n`
- `(a | 1) | (2 | d)` => `(3 | a) | b`

fixes #412
2017-03-03 18:04:32 +08:00
Alex Lam S.L
b5e0e8c203 facilitate fix for #1531 (#1542) 2017-03-03 07:12:24 +08:00
Alex Lam S.L
17b81350d4 fix chained assignment with unused (#1540)
When #1450 optimises `a=b=42`, it stops after the first variable even if both are unused.

fixes #1539
2017-03-03 04:45:20 +08:00
kzc
4d63d4f5b3 collapse_vars should not replace constant in for-in init section (#1538)
fixes #1537
2017-03-03 03:51:15 +08:00
Alex Lam S.L
70d72ad806 properly cover all cases of for-in loop variables (#1536) 2017-03-03 02:39:57 +08:00
Alex Lam S.L
fe9227a41b fix reference marking in for-in loops (#1535)
fixes #1533
2017-03-03 00:56:06 +08:00
Alex Lam S.L
b49e142a26 disable do{...}while(false) optimisation (#1534)
- fails to handle `break` in body

fixes #1532
2017-03-03 00:54:41 +08:00
kzc
ee3b39b909 optimize trivial IIFEs returning constants (#1530) 2017-03-02 15:11:40 +08:00
Alex Lam S.L
9699ffb1af trim unused invocation parameters (#1526) 2017-03-02 11:33:59 +08:00
Alex Lam S.L
fdc9b9413b minor improvement to string optimisation (#1514)
- "" + "a"     => "a"
- "" + a + "b" => a + "b"
- "a" + ""     => "a" (improving on #45)
2017-03-02 11:31:39 +08:00
Alex Lam S.L
7aa69117e1 fix corner cases in reduce_vars (#1524)
Avoid variable substitution in the following cases:
- use of variable before declaration
- declaration within conditional code blocks
- declaration within loop body

fixes #1518
fixes #1525
2017-03-02 00:20:53 +08:00
Alex Lam S.L
c2334baa48 fix crash on missing props to string_template() (#1523)
Patched up `make_node()` without `orig`.

There may be other cases where `start` could be missing, so make it print "undefined" instead of crashing.

fixes #1518
2017-03-01 15:25:26 +08:00
Alex Lam S.L
f5cbe19b75 invert reduce_vars tracking flag (#1519)
Modules like webpack and grunt-contrib-uglify still uses `ast.transform(compressor)` before `Compressor.compress(ast)` was introduced.

Workaround this compatibility issue by deactivating `reduce_vars` in such case.

Also fix use case with omitted `options` when calling `Compressor()`.

fixes #1516
2017-03-01 04:12:10 +08:00
Alex Lam S.L
b34fa11a13 fix evaluate on object getter & setter (#1515) 2017-03-01 02:03:47 +08:00
Alex Lam S.L
4365a51237 temporarily disables reduce_vars (#1517)
... as we investigate #1516
2017-03-01 00:25:43 +08:00
Alex Lam S.L
858e6c78a4 warn & drop #__PURE__ iff IIFE is dropped (#1511)
- consolidate `side-effects` optimisations
- improve string `+` optimisation
- enhance literal & `conditionals` optimisations
2017-02-28 02:25:44 +08:00
Alex Lam S.L
13be50a4a9 faster tree transversal (#1462)
- convert `[].forEach()` to for-loops
2017-02-26 05:58:26 +08:00
Alex Lam S.L
16cd5d57a5 consolidate evaluate & reduce_vars (#1505)
- improve marking efficiency
- apply smarter `const` replacement to `var`

fixes #1501
2017-02-26 00:40:33 +08:00
alexlamsl
4e49302916 enable collapse_vars & reduce_vars by default
- fix corner cases in `const` optimisation
- deprecate `/*@const*/`

fixes #1497
closes #1498
2017-02-24 01:46:57 +08:00
kzc
1e51586996 Support marking a call as pure
A function call or IIFE with an immediately preceding comment
containing `@__PURE__` or `#__PURE__` is deemed to be a
side-effect-free pure function call and can potentially be
dropped.

Depends on `side_effects` option.

`[#@]__PURE__` hint will be removed from comment when pure
call is dropped.

fixes #1261
closes #1448
2017-02-21 14:24:18 +08:00
alexlamsl
26fbeece1c fix pure_funcs & improve side_effects
- only drops side-effect-free arguments
- drop side-effect-free parts with discarded value from `AST_Seq` & `AST_SimpleStatement`

closes #1494
2017-02-21 13:31:59 +08:00
alexlamsl
ec64acd2c8 introduce unsafe_proto
- `Array.prototype.slice` => `[].slice`

closes #1491
2017-02-21 13:29:58 +08:00
alexlamsl
e275148998 enhance global_defs
- support arrays, objects & AST_Node
- support `"a.b":1` on both cli & API
- emit warning if variable is modified
- override top-level variables

fixes #1416
closes #1198
closes #1469
2017-02-21 13:29:58 +08:00
alexlamsl
974247c8c0 evaluate AST_SymbolRef as parameter
fix invalid boolean conversion now exposed in `make_node_from_constant()`

closes #1477
2017-02-21 13:29:58 +08:00
alexlamsl
a0f4fd390a improve reduce_vars and fix a bug
- update modified flag between compress() passes
- support IIFE arguments
- fix corner case with multiple definitions

closes #1473
2017-02-21 13:29:58 +08:00
alexlamsl
b8b133d91a improve keep_fargs & keep_fnames
- utilise in_use_ids instead of unreferenced()
- drop_unused now up-to-date for subsequent passes

closes #1476
2017-02-21 13:29:58 +08:00
kzc
6ffbecb72b smarter const replacement taking name length into account
closes #1459
2017-02-21 13:29:58 +08:00
alexlamsl
f0ff6189be clean up negate_iife
- remove extra tree scanning phase for `negate_iife`
- `negate_iife` now only deals with the narrowest form, i.e. IIFE sitting directly under `AST_SimpleStatement`
- `booleans`, `conditionals` etc. will now take care the rest via more accurate accounting
- `a(); void b();` => `a(); b();`

fixes #1288
closes #1451
2017-02-21 13:29:58 +08:00
alexlamsl
6b3c49e458 improve string concatenation
shuffle associative operations to minimise parentheses and aid other uglification efforts

closes #1454
2017-02-21 13:29:57 +08:00
alexlamsl
f584ca8d07 -c sequences=N suboptimal at N expression cutoff
N = 2:
  a;
  b;
  c;
  d;
was:
  a, b;
  c;
  d;
now:
  a, b;
  c, d;

fixes #1455
closes #1457
2017-02-21 13:29:57 +08:00
alexlamsl
ae4db00991 tweak do-while loops
- `do{...}while(false)` => `{...}`
- clean up `AST_While` logic

closes #1452
2017-02-21 13:29:57 +08:00
alexlamsl
100307ab31 fixes & improvements to [].join()
fixes
- [a].join() => "" + a
- ["a", , "b"].join() => "a,,b"
- ["a", null, "b"].join() => "a,,b"
- ["a", undefined, "b"].join() => "a,,b"

improvements
- ["a", "b"].join(null) => "anullb"
- ["a", "b"].join(undefined) => "a,b"
- [a + "b", c].join("") => a + "b" + c

closes #1453
2017-02-21 13:29:57 +08:00
alexlamsl
148047fbbf drop unused: toplevel, assign-only
- assign statement does not count towards variable usage by default
- only works with assignments on the same scope level as declaration
- can be disabled with `unused` set to "keep_assign"
- `toplevel` to drop unused top-level variables and/or functions
- `top_retain` to whitelist top-level exceptions

closes #1450
2017-02-21 13:29:57 +08:00
kzc
d11dca3cf9 fix stray else in compress with conditionals=false
closes #1449
2017-02-21 13:29:57 +08:00
alexlamsl
e5badb9541 enable typeof "undefined" for general use
move out of unsafe, guard corner case with screw_id8 instead

closes #1446
2017-02-18 19:01:42 +08:00
alexlamsl
11676f9d72 fix crash in unsafe replacement of undefined
remove extraneous call to AST_SymbolRef.reference()

closes #1443
2017-02-18 18:58:23 +08:00