similar to: [LLVMdev] Unwind behaviour in Clang/LLVM

On 6 February 2014 19:21, Richard Smith <richard at metafoo.co.uk> wrote: > > if (nounwind) > can't unwind > can't unwind == unwind table + no EH directives + no EH table if (uwtable || (!nounwind && need uwtable to unwind)) > unwind table > "need unwind table to unwind" is probably true in almost all cases. At least in all where

On 20 March 2014 02:09, Rafael Espíndola <rafael.espindola at gmail.com> wrote: > I think this is just 2. It uses .eh_frame for unwinding proper. The > only difference in .eh_frame is that there is a personality function > defined. If there is no debug information, it should still be possible to unwind the stack via the saved LR on the stack, no? If there is only line info, you

On 21 March 2014 18:47, Logan Chien <tzuhsiang.chien at gmail.com> wrote: > * There's the table for ARM target: > > - no attribute => emit unwind table > - with nounwind => emit unwind table with cantunwind > - with uwtable => emit unwind table > - with uwtable+nounwind => emit unwind table WITHOUT the cantunwind > > The cantunwind record will stop the

> From: Renato Golin [mailto:renato.golin at linaro.org] > > We're having some discussions about the behaviour of exception handling and Dwarf > sharing unwind logic, tables, etc. and it seems that the code around it wasn't > designed with any particular goal in mind, but evolved (like the EHABI) and now > we're seeing the results from it. > > The problems below

> I disagree on this. Table emission by itself doesn't involve code > generation and I don't think it makes sense as a per function attribute > either. You either want it for all functions or only when needed (e.g. > exceptions are possible). As such, it makes perfect sense to me as a > global flag. It has to be an attribute because of LTO. You can LTO a file compiled with

Folks, I'm sorry for getting at this again, but this will not be the last discussion on the topic, so let's just get to business. We're about to merge the last critical patch to make EHABI compatible with other EH mechanisms in LLVM (D3079), and that has unearthed a few issues with the function attributes. Logan's blog post [1] contains a proposal to split unwinding from

I'd love to hear more details. Are you saying that this infinite loop is a limitation of EHABI table format, and not something that can be fixed in the compiler? Meanwhile, please notice that gcc behavior matches current clang behavior that I described above. We would not want to create an incompatibility. On Fri, Feb 14, 2014 at 8:42 PM, Logan Chien <tzuhsiang.chien at gmail.com>

On 7 February 2014 00:19, Richard Smith <richard at metafoo.co.uk> wrote: > This (-fexceptions and -g imply -funwind-tables) seems like it's probably > the right thing for most targets. With SjLj exceptions, -fexceptions > probably doesn't need -funwind-tables. > Thanks, I think that's the general consensus, yes. Do we have such logic in Clang at the moment? My

On 6 February 2014 13:59, Joerg Sonnenberger <joerg at britannica.bec.de>wrote: > This is not true. Even for nounwind, you want to get basic tables so > that backtrace(3) works. > Hi Joerg, It's a matter of consensus, I believe. Is it the general consensus that we will *always* want unwind tables to exist? Code size is a clear reason to not want unwind tables at all, but

Hi Joerg, You are right, there are three separate issues here: unwinding, debug info and exception handling. Debug and EH require unwinding, but one doesn't require the other and unwinding is not exclusive to either. On 6 February 2014 14:51, Joerg Sonnenberger <joerg at britannica.bec.de>wrote: > (1) Should enough unwind data be provided for a basic, read-only stack > walk?

Hi Keith, Anton, Logan, Last time we spoke about ARM unwinding, we agreed to have both CFI and directive variants in ARM, so that both EH and debuggers/profilers could correctly unwind the stack. The problem, obviously, is that we now have redundant information and I decided to have a go commoning them up. One of the issues, I think, is GNU compatibility (so GAS can generate the tables correctly

On Thu, Feb 13, 2014 at 5:52 PM, Renato Golin <renato.golin at linaro.org> wrote: > On 13 February 2014 13:47, Evgeniy Stepanov <eugenis at google.com> wrote: >> Hm, I see that -funwind-tables on arm-linux-androideabi target >> replaces this "cantunwind" with a proper unwind table. >> Hence http://llvm-reviews.chandlerc.com/D2762. > > If Android is

On 10 February 2014 03:44, Renato Golin <renato.golin at linaro.org> wrote: > On 10 February 2014 02:59, Rafael Espíndola <rafael.espindola at gmail.com> wrote: >> It has to be an attribute because of LTO. You can LTO a file compiled >> with -fasynchronous-unwind-tables and one with >> -fno-asynchronous-unwind-tables. That is why we have the uwtable >>

> On 18 Nov 2019, at 22:11, Peter Smith <peter.smith at linaro.org> wrote: > > On Mon, 18 Nov 2019 at 17:06, Sergej Jaskiewicz <jaskiewiczs at icloud.com <mailto:jaskiewiczs at icloud.com>> wrote: >> >> >> >> On 18 Nov 2019, at 19:55, Peter Smith <peter.smith at linaro.org> wrote: >> >> On Mon, 18 Nov 2019 at 15:23, Sergej

On Thu, Feb 13, 2014 at 5:39 PM, Renato Golin <renato.golin at linaro.org> wrote: > On 13 February 2014 11:35, Evgeniy Stepanov <eugenis at google.com> wrote: >> Unwind table index '.ARM.exidx' at offset 0x818 contains 4 entries: >> 0x5d4 <main>: 0x1 [cantunwind] > > This is exactly what I meant. > > >> because the latter prevent any

Hi all, I feel that there are two problems with the existing infrastructure: * The nounwind attribute is ambiguous for (1) not throwing exceptions and (2) not performing stack unwinding. I feel that it will be better to separate this in two different attributes * There is some problem when the function has both uwtable and nounwind. Although, I think it fine to keep the current definition of

> On 18 Nov 2019, at 19:55, Peter Smith <peter.smith at linaro.org> wrote: > > On Mon, 18 Nov 2019 at 15:23, Sergej Jaskiewicz <jaskiewiczs at icloud.com <mailto:jaskiewiczs at icloud.com>> wrote: >> >> Hi Peter, >> >> Thanks for your response. >> >> On 18 Nov 2019, at 17:44, Peter Smith <peter.smith at linaro.org> wrote:

Hello Everyone, This is my first attempt to getting used with the submission process. Trying to get the "good practice" with the coding standard, tools, mailing lists... and already a few questions: - Is it possible to "link" 2 related entries in Phabricator ? one for LLVM and one for CFE ? what's the best way of posting 2 related or dependent patches ? - I'd

Dear all, AFAIK, ARM EHABI is not ready for both asm and obj emitter. Some people including me what to implement them. My question is, to avoid duplicate effort, does someone take charge of this part? or does anyone is already implementing this currently? BTW, any suggestion on this effort? I'm very appreciated! Thanks in advance! -- Best regards, Wen-Han Gu (Nowar) -------------- next

On 12 May 2014 20:20, Logan Chien <tzuhsiang.chien at gmail.com> wrote: > There is a known issue in the code generated by LLVM. > As a workaround, I am adding "-funwind-tables" to compile the unit tests. I thought I had fixed all of them. Do you have a bug number? > BTW, the LLVM revision which I am using is r207501. > It seems that the recent master has come