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support const (#4190)

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This commit is contained in:
Alex Lam S.L
2020-10-11 18:18:57 +01:00
committed by GitHub
parent ffcce28ce1
commit 55451e7b78
15 changed files with 1265 additions and 302 deletions
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334
lib/compress.js
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@@ -370,7 +370,8 @@ merge(Compressor.prototype, {
def.cross_loop = false;
def.direct_access = false;
def.escaped = [];
def.fixed = !def.scope.pinned()
def.fixed = !def.const_redefs
&& !def.scope.pinned()
&& !compressor.exposed(def)
&& !(def.init instanceof AST_Function && def.init !== def.scope)
&& def.init;
@@ -481,8 +482,10 @@ merge(Compressor.prototype, {
return def.fixed instanceof AST_Defun;
}
function safe_to_assign(tw, def) {
if (def.fixed === undefined) return true;
function safe_to_assign(tw, def, declare) {
if (def.fixed === undefined) return declare || all(def.orig, function(sym) {
return !(sym instanceof AST_SymbolConst);
});
if (def.fixed === null && def.safe_ids) {
def.safe_ids[def.id] = false;
delete def.safe_ids;
@@ -654,6 +657,11 @@ merge(Compressor.prototype, {
pop(tw);
return true;
});
def(AST_BlockScope, function(tw, descend, compressor) {
this.variables.each(function(def) {
reset_def(tw, compressor, def);
});
});
def(AST_Call, function(tw, descend) {
tw.find_parent(AST_Scope).may_call_this();
var exp = this.expression;
@@ -717,7 +725,10 @@ merge(Compressor.prototype, {
tw.in_loop = saved_loop;
return true;
});
def(AST_For, function(tw) {
def(AST_For, function(tw, descend, compressor) {
this.variables.each(function(def) {
reset_def(tw, compressor, def);
});
if (this.init) this.init.walk(tw);
var saved_loop = tw.in_loop;
tw.in_loop = this;
@@ -735,7 +746,10 @@ merge(Compressor.prototype, {
tw.in_loop = saved_loop;
return true;
});
def(AST_ForIn, function(tw) {
def(AST_ForIn, function(tw, descend, compressor) {
this.variables.each(function(def) {
reset_def(tw, compressor, def);
});
this.object.walk(tw);
var saved_loop = tw.in_loop;
tw.in_loop = this;
@@ -816,7 +830,10 @@ merge(Compressor.prototype, {
pop(tw);
return true;
});
def(AST_Switch, function(tw) {
def(AST_Switch, function(tw, descend, compressor) {
this.variables.each(function(def) {
reset_def(tw, compressor, def);
});
this.expression.walk(tw);
var first = true;
this.body.forEach(function(branch) {
@@ -900,7 +917,10 @@ merge(Compressor.prototype, {
walk_defuns(tw, this);
return true;
});
def(AST_Try, function(tw) {
def(AST_Try, function(tw, descend, compressor) {
this.variables.each(function(def) {
reset_def(tw, compressor, def);
});
push(tw);
walk_body(this, tw);
pop(tw);
@@ -963,7 +983,7 @@ merge(Compressor.prototype, {
if (!node.value) return;
descend();
var d = node.name.definition();
if (safe_to_assign(tw, d)) {
if (safe_to_assign(tw, d, true)) {
mark(tw, d);
tw.loop_ids[d.id] = tw.in_loop;
d.fixed = function() {
@@ -1667,8 +1687,6 @@ merge(Compressor.prototype, {
extract_candidates(expr.condition);
extract_candidates(expr.consequent);
extract_candidates(expr.alternative);
} else if (expr instanceof AST_Definitions) {
expr.definitions.forEach(extract_candidates);
} else if (expr instanceof AST_Dot) {
extract_candidates(expr.expression);
} else if (expr instanceof AST_DWLoop) {
@@ -1722,6 +1740,8 @@ merge(Compressor.prototype, {
} else {
extract_candidates(expr.expression);
}
} else if (expr instanceof AST_Var) {
expr.definitions.forEach(extract_candidates);
} else if (expr instanceof AST_VarDef) {
if (expr.value) {
var def = expr.name.definition();
@@ -1895,6 +1915,7 @@ merge(Compressor.prototype, {
function get_lhs(expr) {
if (expr instanceof AST_VarDef) {
var def = expr.name.definition();
if (def.const_redefs) return;
if (!member(expr.name, def.orig)) return;
var declared = def.orig.length - def.eliminated - (declare_only[def.name] || 0);
var referenced = def.references.length - def.replaced - (assignments[def.name] || 0);
@@ -2139,11 +2160,15 @@ merge(Compressor.prototype, {
for (var i = 0; i < statements.length;) {
var stat = statements[i];
if (stat instanceof AST_BlockStatement) {
CHANGED = true;
eliminate_spurious_blocks(stat.body);
[].splice.apply(statements, [i, 1].concat(stat.body));
i += stat.body.length;
continue;
if (all(stat.body, function(stat) {
return !(stat instanceof AST_Const);
})) {
CHANGED = true;
eliminate_spurious_blocks(stat.body);
[].splice.apply(statements, [i, 1].concat(stat.body));
i += stat.body.length;
continue;
}
}
if (stat instanceof AST_Directive) {
if (member(stat.value, seen_dirs)) {
@@ -2379,12 +2404,15 @@ merge(Compressor.prototype, {
}
function as_statement_array_with_return(node, ab) {
var body = as_statement_array(node).slice(0, -1);
if (ab.value) {
body.push(make_node(AST_SimpleStatement, ab.value, {
body: ab.value.expression
}));
var body = as_statement_array(node);
var block = body, last;
while ((last = block[block.length - 1]) !== ab) {
block = last.body;
}
block.pop();
if (ab.value) body.push(make_node(AST_SimpleStatement, ab.value, {
body: ab.value.expression
}));
return body;
}
@@ -2430,7 +2458,7 @@ merge(Compressor.prototype, {
statements.length = n;
CHANGED = n != len;
if (has_quit) has_quit.forEach(function(stat) {
extract_declarations_from_unreachable_code(stat, statements);
extract_declarations_from_unreachable_code(compressor, stat, statements);
});
}
@@ -2574,7 +2602,7 @@ merge(Compressor.prototype, {
if (merge_conditional_assignments(def, exprs, keep)) trimmed = true;
break;
}
if (join_var_assign(defn.definitions, exprs, keep)) trimmed = true;
if (defn instanceof AST_Var && join_var_assign(defn.definitions, exprs, keep)) trimmed = true;
}
return trimmed && exprs;
}
@@ -2668,7 +2696,7 @@ merge(Compressor.prototype, {
CHANGED = true;
} else {
statements[++j] = stat;
defs = stat;
if (stat instanceof AST_Var) defs = stat;
}
continue;
} else if (stat instanceof AST_Exit) {
@@ -2690,7 +2718,7 @@ merge(Compressor.prototype, {
defs.definitions = defs.definitions.concat(stat.init.definitions);
stat.init = null;
CHANGED = true;
} else if (stat.init instanceof AST_Definitions) {
} else if (stat.init instanceof AST_Var) {
defs = stat.init;
}
} else if (stat instanceof AST_ForIn) {
@@ -2750,25 +2778,46 @@ merge(Compressor.prototype, {
}
}
function extract_declarations_from_unreachable_code(stat, target) {
function extract_declarations_from_unreachable_code(compressor, stat, target) {
if (!(stat instanceof AST_Defun)) {
AST_Node.warn("Dropping unreachable code [{file}:{line},{col}]", stat.start);
}
stat.walk(new TreeWalker(function(node) {
var block;
stat.walk(new TreeWalker(function(node, descend) {
if (node instanceof AST_Definitions) {
AST_Node.warn("Declarations in unreachable code! [{file}:{line},{col}]", node.start);
node.remove_initializers();
target.push(node);
node.remove_initializers(compressor);
push(node);
return true;
}
if (node instanceof AST_Defun) {
target.push(node);
push(node);
return true;
}
if (node instanceof AST_Scope) {
if (node instanceof AST_Scope) return true;
if (node instanceof AST_BlockScope) {
var save = block;
block = [];
descend();
if (block.required) {
target.push(make_node(AST_BlockStatement, stat, {
body: block
}));
} else if (block.length) {
[].push.apply(target, block);
}
block = save;
return true;
}
}));
function push(node) {
if (block) {
block.push(node);
if (node instanceof AST_Const) block.required = true;
} else {
target.push(node);
}
}
}
function is_undefined(node, compressor) {
@@ -4038,7 +4087,9 @@ merge(Compressor.prototype, {
});
def(AST_SymbolDeclaration, return_false);
def(AST_SymbolRef, function(compressor) {
return !this.is_declared(compressor);
return !(this.is_declared(compressor) && all(this.definition().orig, function(sym) {
return !(sym instanceof AST_SymbolConst);
}));
});
def(AST_This, return_false);
def(AST_Try, function(compressor) {
@@ -4285,12 +4336,15 @@ merge(Compressor.prototype, {
return self;
});
function trim_block(stat) {
switch (stat.body.length) {
case 1: return stat.body[0];
case 0: return make_node(AST_EmptyStatement, stat);
function trim_block(node) {
switch (node.body.length) {
case 0:
return make_node(AST_EmptyStatement, node);
case 1:
var stat = node.body[0];
if (!(stat instanceof AST_Const)) return stat;
}
return stat;
return node;
}
OPT(AST_BlockStatement, function(self, compressor) {
@@ -4386,6 +4440,16 @@ merge(Compressor.prototype, {
pop();
return true;
}
if (node instanceof AST_Const) {
node.definitions.forEach(function(defn) {
var def = defn.name.definition();
references[def.id] = false;
def = def.redefined();
if (def) references[def.id] = false;
defn.value.walk(tw);
});
return true;
}
if (node instanceof AST_For) {
if (node.init) node.init.walk(tw);
push();
@@ -4633,7 +4697,7 @@ merge(Compressor.prototype, {
if (!(sym instanceof AST_SymbolRef)) return;
if (compressor.exposed(sym.definition())) return;
if (!all(sym.definition().orig, function(sym) {
return !(sym instanceof AST_SymbolLambda);
return !(sym instanceof AST_SymbolConst || sym instanceof AST_SymbolLambda);
})) return;
return sym;
};
@@ -4668,42 +4732,40 @@ merge(Compressor.prototype, {
});
}
if (node === self) return;
if (node instanceof AST_Defun) {
var node_def = node.name.definition();
if (!drop_funcs && scope === self) {
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
if (scope === self) {
if (node instanceof AST_Defun) {
var def = node.name.definition();
if (!drop_funcs && !(def.id in in_use_ids)) {
in_use_ids[def.id] = true;
in_use.push(def);
}
initializations.add(def.id, node);
return true; // don't go in nested scopes
}
initializations.add(node_def.id, node);
return true; // don't go in nested scopes
}
if (node instanceof AST_SymbolFunarg && scope === self) {
var node_def = node.definition();
var_defs_by_id.add(node_def.id, node);
assignments.add(node_def.id, node);
}
if (node instanceof AST_Definitions && scope === self) {
node.definitions.forEach(function(def) {
var node_def = def.name.definition();
var_defs_by_id.add(node_def.id, def);
if (!drop_vars) {
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
if (node instanceof AST_Definitions) {
node.definitions.forEach(function(defn) {
var def = defn.name.definition();
var_defs_by_id.add(def.id, defn);
if (!drop_vars && !(def.id in in_use_ids)) {
in_use_ids[def.id] = true;
in_use.push(def);
}
}
if (def.value) {
if (def.value.has_side_effects(compressor)) {
def.value.walk(tw);
if (!defn.value) return;
if (defn.value.has_side_effects(compressor)) {
defn.value.walk(tw);
} else {
initializations.add(node_def.id, def.value);
initializations.add(def.id, defn.value);
}
assignments.add(node_def.id, def);
}
});
return true;
assignments.add(def.id, defn);
});
return true;
}
if (node instanceof AST_SymbolFunarg) {
var def = node.definition();
var_defs_by_id.add(def.id, node);
assignments.add(def.id, node);
return true;
}
}
return scan_ref_scoped(node, descend, true);
});
@@ -4714,7 +4776,14 @@ merge(Compressor.prototype, {
// symbols (that may not be in_use).
tw = new TreeWalker(scan_ref_scoped);
for (var i = 0; i < in_use.length; i++) {
var init = initializations.get(in_use[i].id);
var in_use_def = in_use[i];
if (in_use_def.const_redefs) in_use_def.const_redefs.forEach(function(def) {
if (!(def.id in in_use_ids)) {
in_use_ids[def.id] = true;
in_use.push(def);
}
});
var init = initializations.get(in_use_def.id);
if (init) init.forEach(function(init) {
init.walk(tw);
});
@@ -4915,7 +4984,8 @@ merge(Compressor.prototype, {
}
tail.push(def);
}
} else if (sym.orig[0] instanceof AST_SymbolCatch) {
} else if (sym.orig[0] instanceof AST_SymbolCatch
&& sym.scope.resolve() === def.name.scope.resolve()) {
var value = def.value && def.value.drop_side_effect_free(compressor);
if (value) side_effects.push(value);
var var_defs = var_defs_by_id.get(sym.id);
@@ -5012,7 +5082,13 @@ merge(Compressor.prototype, {
return node;
}
}, function(node, in_list) {
if (node instanceof AST_For) {
if (node instanceof AST_BlockStatement) switch (node.body.length) {
case 0:
return in_list ? List.skip : make_node(AST_EmptyStatement, node);
case 1:
var stat = node.body[0];
if (!(stat instanceof AST_Const)) return stat;
} else if (node instanceof AST_For) {
// Certain combination of unused name + side effect leads to invalid AST:
// https://github.com/mishoo/UglifyJS/issues/44
// https://github.com/mishoo/UglifyJS/issues/1838
@@ -5574,6 +5650,9 @@ merge(Compressor.prototype, {
})
&& all(def.references, function(ref) {
return ref.fixed_value() === right;
})
&& all(def.orig, function(sym) {
return !(sym instanceof AST_SymbolConst);
});
}
});
@@ -5790,7 +5869,9 @@ merge(Compressor.prototype, {
return make_sequence(this, [ expression, property ]);
});
def(AST_SymbolRef, function(compressor) {
return this.is_declared(compressor) ? null : this;
return this.is_declared(compressor) && all(this.definition().orig, function(sym) {
return !(sym instanceof AST_SymbolConst);
}) ? null : this;
});
def(AST_This, return_null);
def(AST_Unary, function(compressor, first_in_statement) {
@@ -5848,26 +5929,24 @@ merge(Compressor.prototype, {
if (!compressor.option("loops")) return self;
var cond = self.condition.is_truthy() || self.condition.evaluate(compressor, true);
if (!(cond instanceof AST_Node)) {
if (cond) return make_node(AST_For, self, {
if (cond && !has_loop_control(self, compressor.parent(), AST_Continue)) return make_node(AST_For, self, {
body: make_node(AST_BlockStatement, self.body, {
body: [
self.body,
make_node(AST_SimpleStatement, self.condition, {
body: self.condition
})
}),
]
})
}).optimize(compressor);
if (!has_loop_control(self, compressor.parent())) {
return make_node(AST_BlockStatement, self.body, {
body: [
self.body,
make_node(AST_SimpleStatement, self.condition, {
body: self.condition
})
]
}).optimize(compressor);
}
if (!has_loop_control(self, compressor.parent())) return make_node(AST_BlockStatement, self.body, {
body: [
self.body,
make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}),
]
}).optimize(compressor);
}
if (self.body instanceof AST_BlockStatement && !has_loop_control(self, compressor.parent(), AST_Continue)) {
var body = self.body.body;
@@ -5877,6 +5956,7 @@ merge(Compressor.prototype, {
&& !stat.alternative
&& stat.body instanceof AST_Break
&& compressor.loopcontrol_target(stat.body) === self) {
if (has_block_scope_refs(stat.condition)) break;
self.condition = make_node(AST_Binary, self, {
operator: "&&",
left: stat.condition.negate(compressor),
@@ -5884,6 +5964,7 @@ merge(Compressor.prototype, {
});
body.splice(i, 1);
} else if (stat instanceof AST_SimpleStatement) {
if (has_block_scope_refs(stat.body)) break;
self.condition = make_sequence(self, [
stat.body,
self.condition,
@@ -5904,6 +5985,18 @@ merge(Compressor.prototype, {
body: make_node(AST_EmptyStatement, self)
}).optimize(compressor);
return self;
function has_block_scope_refs(node) {
var found = false;
node.walk(new TreeWalker(function(node) {
if (found) return true;
if (node instanceof AST_SymbolRef) {
if (!member(node.definition(), self.enclosed)) found = true;
return true;
}
}));
return found;
}
});
function if_break_in_loop(self, compressor) {
@@ -5934,7 +6027,7 @@ merge(Compressor.prototype, {
} else if (retain) {
body.push(first);
}
extract_declarations_from_unreachable_code(self.body, body);
extract_declarations_from_unreachable_code(compressor, self.body, body);
return make_node(AST_BlockStatement, self, {
body: body
});
@@ -5952,7 +6045,7 @@ merge(Compressor.prototype, {
self.condition = first.condition.negate(compressor);
}
var body = as_statement_array(first.alternative);
extract_declarations_from_unreachable_code(first.body, body);
extract_declarations_from_unreachable_code(compressor, first.body, body);
return drop_it(body);
}
ab = first_statement(first.alternative);
@@ -5967,7 +6060,7 @@ merge(Compressor.prototype, {
self.condition = first.condition;
}
var body = as_statement_array(first.body);
extract_declarations_from_unreachable_code(first.alternative, body);
extract_declarations_from_unreachable_code(compressor, first.alternative, body);
return drop_it(body);
}
}
@@ -6015,7 +6108,6 @@ merge(Compressor.prototype, {
if (!cond) {
if (compressor.option("dead_code")) {
var body = [];
extract_declarations_from_unreachable_code(self.body, body);
if (self.init instanceof AST_Statement) {
body.push(self.init);
} else if (self.init) {
@@ -6026,6 +6118,7 @@ merge(Compressor.prototype, {
body.push(make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}));
extract_declarations_from_unreachable_code(compressor, self.body, body);
return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor);
}
} else if (self.condition && !(cond instanceof AST_Node)) {
@@ -6121,21 +6214,23 @@ merge(Compressor.prototype, {
}
if (!cond) {
AST_Node.warn("Condition always false [{file}:{line},{col}]", self.condition.start);
var body = [];
extract_declarations_from_unreachable_code(self.body, body);
body.push(make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}));
var body = [
make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}),
];
extract_declarations_from_unreachable_code(compressor, self.body, body);
if (self.alternative) body.push(self.alternative);
return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor);
} else if (!(cond instanceof AST_Node)) {
AST_Node.warn("Condition always true [{file}:{line},{col}]", self.condition.start);
var body = [];
if (self.alternative) extract_declarations_from_unreachable_code(self.alternative, body);
body.push(make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}));
body.push(self.body);
var body = [
make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}),
self.body,
];
if (self.alternative) extract_declarations_from_unreachable_code(compressor, self.alternative, body);
return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor);
}
}
@@ -6459,7 +6554,7 @@ merge(Compressor.prototype, {
if (prev && !aborts(prev)) {
prev.body = prev.body.concat(branch.body);
} else {
extract_declarations_from_unreachable_code(branch, decl);
extract_declarations_from_unreachable_code(compressor, branch, decl);
}
}
});
@@ -6470,9 +6565,9 @@ merge(Compressor.prototype, {
if (has_declarations_only(self)) {
var body = [];
if (self.bcatch) {
extract_declarations_from_unreachable_code(self.bcatch, body);
extract_declarations_from_unreachable_code(compressor, self.bcatch, body);
body.forEach(function(stat) {
if (!(stat instanceof AST_Definitions)) return;
if (!(stat instanceof AST_Var)) return;
stat.definitions.forEach(function(var_def) {
var def = var_def.name.definition().redefined();
if (!def) return;
@@ -6499,7 +6594,13 @@ merge(Compressor.prototype, {
return self;
});
AST_Definitions.DEFMETHOD("remove_initializers", function() {
AST_Const.DEFMETHOD("remove_initializers", function(compressor) {
this.definitions.forEach(function(def) {
def.value = make_node(AST_Undefined, def).optimize(compressor);
});
});
AST_Var.DEFMETHOD("remove_initializers", function() {
this.definitions.forEach(function(def) {
def.value = null;
});
@@ -6526,8 +6627,31 @@ merge(Compressor.prototype, {
return make_sequence(this, assignments);
});
OPT(AST_Definitions, function(self, compressor) {
return self.definitions.length ? self : make_node(AST_EmptyStatement, self);
OPT(AST_Const, function(self, compressor) {
return all(self.definitions, function(defn) {
var node = defn.name;
if (!node.fixed_value()) return false;
var def = node.definition();
var scope = def.scope.resolve();
if (scope instanceof AST_Toplevel) {
if (!compressor.toplevel.vars) return false;
if (def.scope === scope) return true;
return !scope.variables.has(node.name) && !scope.globals.has(node.name);
}
return def.scope === scope || !scope.find_variable(node);
}) ? make_node(AST_Var, self, {
definitions: self.definitions.map(function(defn) {
var name = make_node(AST_SymbolVar, defn.name, defn.name);
var def = name.definition();
def.orig[def.orig.indexOf(defn.name)] = name;
var scope = def.scope.resolve();
if (def.scope !== scope) scope.variables.set(def.name, def);
return make_node(AST_VarDef, defn, {
name: name,
value: defn.value
});
})
}) : self;
});
function lift_sequence_in_expression(node, compressor) {