Increase the "local variables in a function" limit.

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

diff --git a/src/messages.js b/src/messages.js
index e6365a4..bc14785 100644 (file)
--- a/src/messages.js
+++ b/src/messages.js
@@ -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"],

diff --git a/src/parser.h b/src/parser.h
index 3d2f032..f3984e8 100644 (file)
--- a/src/parser.h
+++ b/src/parser.h
@@ -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,

diff --git a/test/mjsunit/limit-locals.js b/test/mjsunit/limit-locals.js
deleted file mode 100644 (file)
index 1d36c80..0000000
--- a/test/mjsunit/limit-locals.js
+++ /dev/null
@@ -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)");