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Increase the "local variables in a function" limit.

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The limit was originally added to avoid having large user-controlled constants
(variable indexes) in the code generated by full-codegen.

History behind this change:

The original CL for adding the limit was https://codereview.chromium.org/7003030
and at that time, the limit was 32767.

Reason for adding the limit (in CL comments): "The motivation behind this change
is to avoid large user controlled constants in the code. The slot_operand used
in the IA32 full code generator uses a relative load where the local index is an
(negative) immediate."

The limit was then bumped to 65535 by https://codereview.chromium.org/10965063
and to 131071 by https://codereview.chromium.org/11099063.

R=dcarney@chromium.org, svenpanne@chromium.org, jkummerow@chromium.org, rossberg@chromium.org
BUG=v8:3205
LOG=Y

Review URL: https://codereview.chromium.org/206143004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20126 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
marja@chromium.org 2014-03-20 13:37:26 +00:00
parent d017e6ce54
commit e9358fa9ce
3 changed files with 9 additions and 49 deletions
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2
src/messages.js
View File

@ -157,7 +157,7 @@ var kMessages = {
strict_eval_arguments: ["Unexpected eval or arguments in strict mode"],
too_many_arguments: ["Too many arguments in function call (only 65535 allowed)"],
too_many_parameters: ["Too many parameters in function definition (only 65535 allowed)"],
too_many_variables: ["Too many variables declared (only 131071 allowed)"],
too_many_variables: ["Too many variables declared (only 4194303 allowed)"],
strict_param_dupe: ["Strict mode function may not have duplicate parameter names"],
strict_octal_literal: ["Octal literals are not allowed in strict mode."],
strict_duplicate_property: ["Duplicate data property in object literal not allowed in strict mode"],

9
src/parser.h
View File

@ -618,7 +618,14 @@ class Parser : public ParserBase<ParserTraits> {
private:
friend class ParserTraits;
static const int kMaxNumFunctionLocals = 131071; // 2^17-1
// Limit the allowed number of local variables in a function. The hard limit
// is that offsets computed by FullCodeGenerator::StackOperand and similar
// functions are ints, and they should not overflow. In addition, accessing
// local variables creates user-controlled constants in the generated code,
// and we don't want too much user-controlled memory inside the code (this was
// the reason why this limit was introduced in the first place; see
// https://codereview.chromium.org/7003030/ ).
static const int kMaxNumFunctionLocals = 4194303; // 2^22-1
enum Mode {
PARSE_LAZILY,

47
test/mjsunit/limit-locals.js
View File

@ -1,47 +0,0 @@
// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Test that there is a limit of 131071 locals.
// Flags: --stack-size=1200
function function_with_n_locals(n) {
test_prefix = "prefix ";
test_suffix = " suffix";
var src = "test_prefix + (function () {"
for (var i = 1; i <= n; i++) {
src += "; var x" + i;
}
src += "; return " + n + ";})() + test_suffix";
return eval(src);
}
assertEquals("prefix 0 suffix", function_with_n_locals(0));
assertEquals("prefix 16000 suffix", function_with_n_locals(16000));
assertEquals("prefix 131071 suffix", function_with_n_locals(131071));
assertThrows("function_with_n_locals(131072)");