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enhance passes (#2229)

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- remove hardcoded upper limit
- continue based on node count reduction
- emit verbose statistics

fixes #2226
This commit is contained in:
Alex Lam S.L
2017-07-13 02:18:59 +08:00
committed by GitHub
parent c615a1e80a
commit 458e3e15f0
3 changed files with 40 additions and 26 deletions
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2
README.md
View File

@@ -721,7 +721,7 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
compressor from discarding function names. Useful for code relying on
`Function.prototype.name`. See also: the `keep_fnames` [mangle option](#mangle).
- `passes` -- default `1`. Number of times to run compress with a maximum of 3.
- `passes` -- default `1`. The maximum number of times to run compress.
In some cases more than one pass leads to further compressed code. Keep in
mind more passes will take more time.

12
lib/compress.js
View File

@@ -148,10 +148,20 @@ merge(Compressor.prototype, {
node.process_expression(true);
}
var passes = +this.options.passes || 1;
for (var pass = 0; pass < passes && pass < 3; ++pass) {
var last_count = 1 / 0;
for (var pass = 0; pass < passes; pass++) {
if (pass > 0 || this.option("reduce_vars"))
node.reset_opt_flags(this, true);
node = node.transform(this);
if (passes > 1) {
var count = 0;
node.walk(new TreeWalker(function() {
count++;
}));
this.info("pass " + pass + ": last_count: " + last_count + ", count: " + count);
if (count >= last_count) break;
last_count = count;
}
}
if (this.option("expression")) {
node.process_expression(false);

52
test/compress/issue-1034.js
View File

@@ -71,11 +71,13 @@ non_hoisted_function_after_return_2a: {
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:51,16]",
"WARN: Dropping unused variable a [test/compress/issue-1034.js:48,20]",
"WARN: Dropping unused function nope [test/compress/issue-1034.js:55,21]",
"WARN: pass 0: last_count: Infinity, count: 37",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:53,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:53,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:56,12]",
"WARN: Dropping unused variable b [test/compress/issue-1034.js:51,20]",
"WARN: Dropping unused variable c [test/compress/issue-1034.js:53,16]",
"WARN: pass 1: last_count: 37, count: 18",
]
}
@@ -109,11 +111,11 @@ non_hoisted_function_after_return_2b: {
}
expect_warnings: [
// duplicate warnings no longer emitted
"WARN: Dropping unreachable code [test/compress/issue-1034.js:95,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:95,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:97,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:97,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:101,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:97,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:97,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:99,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:99,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:103,12]",
]
}
@@ -151,10 +153,10 @@ non_hoisted_function_after_return_strict: {
}
expect_stdout: "8 7"
expect_warnings: [
'WARN: Dropping unreachable code [test/compress/issue-1034.js:131,16]',
"WARN: Dropping unreachable code [test/compress/issue-1034.js:134,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:137,12]",
"WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:138,21]"
"WARN: Dropping unreachable code [test/compress/issue-1034.js:133,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:136,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:139,12]",
"WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:140,21]",
]
}
@@ -194,17 +196,19 @@ non_hoisted_function_after_return_2a_strict: {
}
expect_stdout: "5 6"
expect_warnings: [
"WARN: Dropping unreachable code [test/compress/issue-1034.js:173,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:173,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:176,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:176,16]",
"WARN: Dropping unused variable a [test/compress/issue-1034.js:173,20]",
"WARN: Dropping unused function nope [test/compress/issue-1034.js:180,21]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:178,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:178,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:181,12]",
"WARN: Dropping unused variable b [test/compress/issue-1034.js:176,20]",
"WARN: Dropping unused variable c [test/compress/issue-1034.js:178,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:175,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:175,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:178,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:178,16]",
"WARN: Dropping unused variable a [test/compress/issue-1034.js:175,20]",
"WARN: Dropping unused function nope [test/compress/issue-1034.js:182,21]",
"WARN: pass 0: last_count: Infinity, count: 48",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:180,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:180,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:183,12]",
"WARN: Dropping unused variable b [test/compress/issue-1034.js:178,20]",
"WARN: Dropping unused variable c [test/compress/issue-1034.js:180,16]",
"WARN: pass 1: last_count: 48, count: 29",
]
}
@@ -243,10 +247,10 @@ non_hoisted_function_after_return_2b_strict: {
expect_stdout: "5 6"
expect_warnings: [
// duplicate warnings no longer emitted
"WARN: Dropping unreachable code [test/compress/issue-1034.js:225,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:225,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:227,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:227,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:229,16]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:229,16]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:231,12]",
"WARN: Declarations in unreachable code! [test/compress/issue-1034.js:231,12]",
"WARN: Dropping unreachable code [test/compress/issue-1034.js:235,12]",
]
}