The JIT has a codepath that supports JIT memory managers that return true for NeedsExactSize(). This is particularly bad for X86, because the "exact size" is not exact, and looks completely wrong in a lot of cases. Is anyone using this? Can I rip it out? This stuff should go away with the mc'ization of the JIT in the long term. -Chris
Oh god, rip it out. IIRC it's just a complete parallel reimplementation of bunch of instruction encoding stuff just to compute the code size. Reid On Wed, Jul 21, 2010 at 3:52 PM, Chris Lattner <clattner at apple.com> wrote:> The JIT has a codepath that supports JIT memory managers that return true for NeedsExactSize(). This is particularly bad for X86, because the "exact size" is not exact, and looks completely wrong in a lot of cases. Is anyone using this? Can I rip it out? This stuff should go away with the mc'ization of the JIT in the long term. > > -Chris > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
On Jul 21, 2010, at 5:01 PM, Reid Kleckner wrote:> Oh god, rip it out. IIRC it's just a complete parallel > reimplementation of bunch of instruction encoding stuff just to > compute the code size.Yeah, I know. It's the 3rd and most incorrect copy of the instruction emitter. I really really want to rip it out, but we do have a unit test for the 'needsexactsize()' stuff, so I figure someone might actually care. Does vmkit use this? -Chris> > Reid > > On Wed, Jul 21, 2010 at 3:52 PM, Chris Lattner <clattner at apple.com> wrote: >> The JIT has a codepath that supports JIT memory managers that return true for NeedsExactSize(). This is particularly bad for X86, because the "exact size" is not exact, and looks completely wrong in a lot of cases. Is anyone using this? Can I rip it out? This stuff should go away with the mc'ization of the JIT in the long term. >> >> -Chris >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>
Reasonably Related Threads
- [LLVMdev] JIT memory manager: NeedsExactSize() ?
- [LLVMdev] JIT memory manager: NeedsExactSize() ?
- [LLVMdev] vmkit, jvm, newbie bytecode translation + jit question
- [LLVMdev] Disable JIT and interpret code instead in VMKit
- [LLVMdev] Importance of VMKit JIT function cache