similar to: [LLVMdev] _Unwind_Exception and _Unwind_Resume

On Mar 6, 2011, at 11:01 AM, Talin wrote: > Here's an interesting problem - is it legal to copy the _Unwind_Exception struct to a different address in memory before calling _Unwind_Resume? > > I'm thinking of the scenario in which a garbage collection run is triggered in the middle of a "finally" block. If it's a copying collector, it might relocate the exception

On Sun, Mar 6, 2011 at 7:37 PM, John McCall <rjmccall at apple.com> wrote: > On Mar 6, 2011, at 11:01 AM, Talin wrote: > > Here's an interesting problem - is it legal to copy the _Unwind_Exception > struct to a different address in memory before calling _Unwind_Resume? > > > > I'm thinking of the scenario in which a garbage collection run is > triggered in

Can you point out to me where in the VMKit code I should be looking? I spent some additional time reading the docs, and I have some specific questions: 1) I'm trying to figure out the relationship between the __cxa_throw function, and the _Unwind_RaiseException function mentioned in the ABI doc. My guess is that _Unwind_RaiseException is the language-neutral implementation of stack unwinding,

On Mon, Mar 7, 2011 at 4:08 AM, nicolas geoffray <nicolas.geoffray at gmail.com > wrote: > Hi Talin, > > On Sat, Mar 5, 2011 at 6:42 PM, Talin <viridia at gmail.com> wrote: >> >> >> So I've been thinking about your proposal, that of using a special address >> space to indicate garbage collection roots instead of intrinsics. > > > Great!

On Tue, Sep 21, 2010 at 8:20 PM, Talin <viridia at gmail.com> wrote: > On Mon, Sep 20, 2010 at 3:16 PM, Talin <viridia at gmail.com> wrote: >> >> So I've managed to get my stack crawler working and passing its unit tests >> - this is the one I've been working on as an alternative to shadow-stack: it >> uses only static constant data structures (no

On Wed, Sep 22, 2010 at 5:58 AM, Kenneth Uildriks <kennethuil at gmail.com>wrote: > On Tue, Sep 21, 2010 at 8:20 PM, Talin <viridia at gmail.com> wrote: > > On Mon, Sep 20, 2010 at 3:16 PM, Talin <viridia at gmail.com> wrote: > >> > >> So I've managed to get my stack crawler working and passing its unit > tests > >> - this is the one

On Mon, Feb 21, 2011 at 1:50 AM, nicolas geoffray < nicolas.geoffray at gmail.com> wrote: > Hi Talin, > > On Fri, Feb 18, 2011 at 5:50 PM, Talin <viridia at gmail.com> wrote: >> >> >> In the current scheme, the way you tell LLVM that a root is no longer >> needed is by assigning NULL to it. However, that assumes that all roots are >> pointers,

Forgive my top post but I hate Windows. J I am surprised you (Talin) say that "we know conservative collectors work" because my experience has very much been of them not working. Indeed, if you have 400Mb of allocated heap blocks on a 32-bit machine is there not a 10% chance of *each* random 32-bit int "pointing" into your heap, i.e. a false positive? I just did a simple

Hi Talin, On Sat, Mar 5, 2011 at 6:42 PM, Talin <viridia at gmail.com> wrote: > > > So I've been thinking about your proposal, that of using a special address > space to indicate garbage collection roots instead of intrinsics. Great! > > To address this, we need a better way of telling LLVM that a given variable > is no longer a root. > Live variable

Hi all, I've been looking through the documentation (http://llvm.org/docs/GarbageCollection.html) on how to implement a garbage collector for LLVM and there's a couple of things that I don't quite understand. Specifically, it says that when a stack variable goes out of scope, you're supposed to assign a null value to it to indicate that the value is no longer live. What I

Hi Talin, > 1) I'm trying to figure out the relationship between the __cxa_throw > function, and the _Unwind_RaiseException function mentioned in the ABI doc. > My guess is that _Unwind_RaiseException is the language-neutral > implementation of stack unwinding, and __cxa_throw is the C++ exception > semantics that are implemented on top of it. If that is the case, should I >

On Sep 2, 2007 5:31 AM, Gordon Henriksen <gordonhenriksen at mac.com> wrote: > Hi Talin, > > On Sep 2, 2007, at 04:54, Talin wrote: > > > I've been looking through the documentation (http://llvm.org/docs/ > > GarbageCollection.html) on how to implement a garbage collector for > > LLVM and there's a couple of things that I don't quite understand. >

Talin, how about having the front-end generate an llvm.safe.point () intrinsic call at the desired safe points, and having the addresses of the GC roots (at that point, can vary from call to call) be the parameters (with noescape attribute) to the intrinsic, IIUC currently the GC roots are tagged, and all analysis and transform optimizations have to special case these tagged

On Fri, Feb 18, 2011 at 1:05 AM, nicolas geoffray < nicolas.geoffray at gmail.com> wrote: > Hi Talin, > > On Fri, Feb 18, 2011 at 1:36 AM, Talin <viridia at gmail.com> wrote: >> >> Thinking about it even more, here's a short summary of what I would >> propose: >> >> - *llvm.gc.value*(value, metadata) - marks an SSA value as a garbage

Just a thought, but it would it make sense for garbage collection to be some sort of minimal debug information for potentially optimized code. Store just enough debug information to reconstruct call stacks and know where gc-roots are. Perhaps an approach like this could minimize the work required as it is shared between gc-support and debug information support. >From what I understand, DWARF

> On Feb 2, 2015, at 4:53 PM, Reid Kleckner <rnk at google.com> wrote: > This seems reasonable to me. Adding John explicitly… Thanks, Reid. Andy, I understand why Windows EH needs custom lowering here, and using intrinsics seems like a fine approach, but I don’t understand why you’re proposing changing the Itanium code generation pattern. There’s no reason for backends to have

Hi Talin, On Sep 2, 2007, at 04:54, Talin wrote: > I've been looking through the documentation (http://llvm.org/docs/ > GarbageCollection.html) on how to implement a garbage collector for > LLVM and there's a couple of things that I don't quite understand. > Specifically, it says that when a stack variable goes out of scope, > you're supposed to assign a

Hi Talin, Talin wrote: > After much delay, I have finally reached the point in my work where I > need to implement some kind of exception handling. I understand that > "unwind" is currently unimplemented and will remain so for the > forseeable future. > > In the mean time, are there any examples available for implementing Java > or Python-style exceptions using

After much delay, I have finally reached the point in my work where I need to implement some kind of exception handling. I understand that "unwind" is currently unimplemented and will remain so for the forseeable future. In the mean time, are there any examples available for implementing Java or Python-style exceptions using __cxa_throw or something similar? I've read and

Talin, do you identify safe-points in the current or proposed llvm scheme, and if so how, or are they implicit as being at all call sites (which begs the question what about leaves in the call tree, how does GC get started at all in that case). Peter Lawrence.