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enhance collapse_vars (#3572)

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This commit is contained in:
Alex Lam S.L
2019-11-05 18:15:28 +08:00
committed by GitHub
parent 0e29ad5eb9
commit 3e2c51a4da
2 changed files with 79 additions and 5 deletions
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36
lib/compress.js
View File

@@ -1235,7 +1235,7 @@ merge(Compressor.prototype, {
var lvalues = get_lvalues(candidate);
var lhs_local = is_lhs_local(lhs);
if (!side_effects) side_effects = value_has_side_effects(candidate);
var replace_all = replace_all_symbols();
var replace_all = replace_all_symbols(candidate);
var may_throw = candidate.may_throw(compressor) ? in_try ? function(node) {
return node.has_side_effects(compressor);
} : side_effects_external : return_false;
@@ -1312,6 +1312,7 @@ merge(Compressor.prototype, {
function in_conditional(node, parent) {
if (parent instanceof AST_Binary) return lazy_op[parent.operator] && parent.left !== node;
if (parent instanceof AST_Case) return parent.expression !== node;
if (parent instanceof AST_Conditional) return parent.condition !== node;
return parent instanceof AST_If && parent.condition !== node;
}
@@ -1477,19 +1478,43 @@ merge(Compressor.prototype, {
if (parent instanceof AST_Call) return node;
if (parent instanceof AST_Case) return node;
if (parent instanceof AST_Conditional) return node;
if (parent instanceof AST_Definitions) return find_stop(parent, level + 1);
if (parent instanceof AST_Definitions) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Exit) return node;
if (parent instanceof AST_If) return node;
if (parent instanceof AST_IterationStatement) return node;
if (parent instanceof AST_PropAccess) return node;
if (parent instanceof AST_Sequence) return find_stop(parent, level + 1);
if (parent instanceof AST_SimpleStatement) return find_stop(parent, level + 1);
if (parent instanceof AST_Sequence) {
return (parent.tail_node() === node ? find_stop : find_stop_unused)(parent, level + 1);
}
if (parent instanceof AST_SimpleStatement) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Switch) return node;
if (parent instanceof AST_Unary) return node;
if (parent instanceof AST_VarDef) return node;
return null;
}
function find_stop_unused(node, level) {
var parent = scanner.parent(level);
if (is_last_node(node, parent)) return node;
if (in_conditional(node, parent)) return node;
if (parent instanceof AST_Assign) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Binary) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Call) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Case) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Conditional) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Definitions) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Exit) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_If) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_IterationStatement) return node;
if (parent instanceof AST_PropAccess) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Sequence) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_SimpleStatement) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Switch) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Unary) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_VarDef) return find_stop_unused(parent, level + 1);
return null;
}
function mangleable_var(var_def) {
var value = var_def.value;
if (!(value instanceof AST_SymbolRef)) return;
@@ -1656,7 +1681,8 @@ merge(Compressor.prototype, {
return get_rvalue(expr).has_side_effects(compressor);
}
function replace_all_symbols() {
function replace_all_symbols(expr) {
if (expr instanceof AST_Unary) return false;
if (side_effects) return false;
if (value_def) return true;
if (lhs instanceof AST_SymbolRef) {

48
test/compress/collapse_vars.js
View File

@@ -6387,3 +6387,51 @@ issue_3562: {
}
expect_stdout: "PASS PASS"
}
dot_throw_assign_sequence: {
options = {
collapse_vars: true,
}
input: {
var a = "FAIL";
try {
var b;
b[0] = (a = "PASS", 0);
a = 1 + a;
} catch (c) {
}
console.log(a);
}
expect: {
var a = "FAIL";
try {
var b;
b[0] = (a = "PASS", 0);
a = 1 + a;
} catch (c) {
}
console.log(a);
}
expect_stdout: "PASS"
}
call_assign_order: {
options = {
collapse_vars: true,
}
input: {
var a, b = 1, c = 0, log = console.log;
(function() {
a = b = "PASS";
})((b = "FAIL", c++));
log(a, b);
}
expect: {
var a, b = 1, c = 0, log = console.log;
(function() {
a = b = "PASS";
})((b = "FAIL", c++));
log(a, b);
}
expect_stdout: "PASS PASS"
}