VEX

Posted Aug 19, 2009 17:55 UTC (Wed) by abacus (guest, #49001)
Parent article: Google's Chromium sandbox

I'm surprised that the article doesn't mention the VEX library, the core of the Valgrind tool suite. This is a library that allows to disassemble i386, x86_86 and ppc assembly code to an intermediate representation and also back to assembly. I don't doubt that the Chromium authors know about the existence of VEX and that they had good reasons to write their own disassembly code instead of using the VEX library. But I'm curious to know why.

VEX

Posted Aug 19, 2009 19:04 UTC (Wed) by agl (guest, #4541) [Link]

As the text mentions, the disassembler didn't actually turn out to be all
that much code, so the motivation to use something pre-existing was less.

But also, we wouldn't want to transform all the code back and forth. By
patching the code rather than transforming it we can reuse nearly all the
.text pages and save memory.