Don't use string slices when processing RexExp replace

Don't use string slices when processing RexExp replace.

String slices from RegExp replace results is now encoded in either one or two smis. Substrings are not used any more.

If the existing one smi encoding cannot hold the start/length information two smis are used the first having the negative length and the second having the start.

This is in preparation for removing string slices.

Committed: http://code.google.com/p/v8/source/detail?r=3153

[Erik Corry, 2009-10-28 08:24:07]

LGTM with a few extra checks.

http://codereview.chromium.org/342015/diff/4001/5001
File src/runtime.cc (right):

http://codereview.chromium.org/342015/diff/4001/5001#newcode3806
Line 3806: // This assumpsion is used by the slice encoding in one or two smis.
assumpsion -> assumption

http://codereview.chromium.org/342015/diff/4001/5001#newcode3849
Line 3849: i++;  // Skip position
Needs to be checked for type/range.

http://codereview.chromium.org/342015/diff/4001/5002
File src/string.js (right):

http://codereview.chromium.org/342015/diff/4001/5002#newcode2
Line 2: // modification, are permitted provided that the following conditions
are
This looks unintentional.

http://codereview.chromium.org/342015/diff/4001/5002#newcode812
Line 812: if (start >= 0 && len > 0 && start < 0x80000 && len < 0x800) {
Start and len will never be < 0 so we should omit this test.

[Søren Thygesen Gjesse, 2009-10-28 08:53:32]

http://codereview.chromium.org/342015/diff/4001/5001
File src/runtime.cc (right):

http://codereview.chromium.org/342015/diff/4001/5001#newcode3806
Line 3806: // This assumpsion is used by the slice encoding in one or two smis.
On 2009/10/28 08:24:07, Erik Corry wrote:
> assumpsion -> assumption

Done.

http://codereview.chromium.org/342015/diff/4001/5001#newcode3849
Line 3849: i++;  // Skip position
On 2009/10/28 08:24:07, Erik Corry wrote:
> Needs to be checked for type/range.

Done.

http://codereview.chromium.org/342015/diff/4001/5002
File src/string.js (right):

http://codereview.chromium.org/342015/diff/4001/5002#newcode2
Line 2: // modification, are permitted provided that the following conditions
are
On 2009/10/28 08:24:07, Erik Corry wrote:
> This looks unintentional.

Reverted with 2008->2009

http://codereview.chromium.org/342015/diff/4001/5002#newcode812
Line 812: if (start >= 0 && len > 0 && start < 0x80000 && len < 0x800) {
On 2009/10/28 08:24:07, Erik Corry wrote:
> Start and len will never be < 0 so we should omit this test.

Done.