search for: ifunc

Hi Everyone, I would like to implement GCC ifunc attribute support in Clang and LLVM. At the moment Clang ignores the attribute with a warning. On LLVM IR level there is no support for ifunc. But there is some support for ELF symbol type `@gnu_indirect_function` in ELF reader/writer/target asm parser. This RFC is looking for thoughts and suggesti...

I would like to support __attribute__((target)) later so ifunc won't be opaque for compiler generated dispatchers. Thank you all for the feedback! On Sat, Dec 19, 2015 at 8:49 AM, Eric Christopher via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I think 2 is the only reasonable answer. And to answer Reid's comment: > yes, it might be...

...more than once I wished we had an easy way to iterate all GlobalValues or all GrobalObjects. Any thoughts on the tradeoff having a single list with pointer to the start of each sub list? Something like Func1 <-> Func2 <-> Var1 <-> Var2 <-> Alias1 <-> Alias2 <-> IFunc1 <-> Ifunc2 and keep FirstFunc, FirstVar, FirstAlias and FirstIFunc pointers. One place where having another list might be a bit annoying is the symbol iterator of IRObjectFile. Cheers, Rafael On 22 December 2015 at 08:23, Dmitry Polukhin <dmitry.polukhin at gmail.com> wrote: >...

Are you going to have to teach LLVM how to look through ifuncs, or is it OK if they are totally opaque? For example, with __attribute__((target)), you might have one target-specialized function call another. Is it important that we be able to optimize away the dynamic dispatch there or not? Either way, I think a new IR construct is the way to go. On Fri, D...

Hello, We've recently started using ifuncs in the x86(_64) FreeBSD kernel. Currently lld will emit a PLT entry for each ifunc, so ifunc calls are more expensive that those of regular functions. In our kernel, this overhead isn't really necessary: if lld instead emits PC-relative relocations for each ifunc call site, where each relocat...

Hi, I just spent 4 hours trying to find a way to get the name of the resolver function of a ifunc definition ... :-( and with all that time I didnt event get far: for (GlobalIFunc &IF : M.ifuncs()) { StringRef ifunc_name = IF.getName(); Constant *r = IF.getResolver(); But how do I get to the (Function*) or function name of the resolver from there? I tried everything with the Constant...

..."character" > length(allBP) [1] 16066 > I want to create a function so that I can execute the command by passing as a parameter the portion in quotes in the above command (""GO:0008150"). So my current function looks like: > str <- "GO:0008150" > ifunc <- function(str){ + allBP <- paste('GOBPOFFSPRING$',str,sep='') + return(allBP) + } > x <- ifunc(str) > class(x) [1] "character" > length(x) [1] 1 > But this just returns a string. How do I get the command to execute? thanks! [[alternative...

In the context of support not only IFunc but DTrace, what kind of features do you want to add to lld, if you have a chance to implement it in the linker instead of a post-processing tool? I wonder if we can solve both of your problems. On Thu, Aug 23, 2018 at 1:33 AM Mark Johnston <markj at freebsd.org> wrote: > On Wed, Aug 22,...

Hi, It looks like the the ELFPassFile doesnot get an ordinal value assigned, as its added in a pass. Is there a way to assign a file ordinal for the files added by Passes ? Till that time, I am going to XFAIL the ifunc test. More tests should fail, and am not sure why they are not failing. Thanks Shankar Easwaran -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by the Linux Foundation

I was working on https://reviews.llvm.org/D81911 to try and fix https://bugs.llvm.org/show_bug.cgi?id=46340 . Through the review process we happened upon a design limitation or perhaps a potential mis-modelling of GlobalIFunc in the IR object hierarchy, which leads to some problems in LTO flows. To summarize, as it currently stands (and in the hopes of faithfully representing the conclusions of that discussion): * Calling getBaseObject() on a GlobalAlias whose aliasee is a GlobalIFunc currently returns null. * Calling...

...n 10/6/2013 10:54 PM, Shankar Easwaran wrote: > Hi, > > It looks like the the ELFPassFile doesnot get an ordinal value > assigned, as its added in a pass. > > Is there a way to assign a file ordinal for the files added by Passes ? > > Till that time, I am going to XFAIL the ifunc test. > > More tests should fail, and am not sure why they are not failing. > > Thanks > > Shankar Easwaran > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by the Linux Foundation

...-dev at lists.llvm.org> wrote: > > However, if you pass the -emit-relocs option to the linker, lld keeps all > relocations that have already been resolved in an output executable. By > analyzing a relocation table in a resulting executable, you could find all > locations where the ifunc PLT is called. Then, you can construct a new table > for your linker, embed it to the executable using objcopy or something like > that, and then let the kernel loader interpret it. > > Have you considered that? I've thought about alternative ways to achieve the same thing, includi...

...swaran wrote: >> Hi, >> >> It looks like the the ELFPassFile doesnot get an ordinal value >> assigned, as its added in a pass. >> >> Is there a way to assign a file ordinal for the files added by Passes ? >> >> Till that time, I am going to XFAIL the ifunc test. >> >> More tests should fail, and am not sure why they are not failing. >> >> Thanks >> >> Shankar Easwaran >> > > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by the Linux Foundation

> * Calling getBaseObject() on a GlobalIFunc returns its resolver function. I still don't understand how it can happen looking to the code ( https://github.com/llvm/llvm-project/blob/master/llvm/lib/IR/Globals.cpp#L430). I believe it should return nullptr (the same as if you call it from GlobalAlias that refers to GlobalIFunc). I don...

Friends, I'm trying to pass an equation as an argument to a function. The idea is as follows. Let us say i write an independent function Ideal Situation: ifunc <- function(x) { return((x*x)-2) } mainfunc <- function(a,b) { evala <- ifunc(a) evalb <- ifunc(b) if (evala>evalb){return(evala)} else return(evalb) } Now I want to try and write this entire program in a single function with the user specifying the equation as an argument to the f...

...>>> >>> It looks like the the ELFPassFile doesnot get an ordinal value assigned, >>> as its added in a pass. >>> >>> Is there a way to assign a file ordinal for the files added by Passes ? >>> >>> Till that time, I am going to XFAIL the ifunc test. >>> >>> More tests should fail, and am not sure why they are not failing. >>> >>> Thanks >>> >>> Shankar Easwaran >>> >>> >> >> > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora For...

On 10/7/2013 3:43 PM, Rui Ueyama wrote: > On Mon, Oct 7, 2013 at 11:51 AM, Shankar Easwaran > <shankare at codeaurora.org>wrote: > >> Ping ? >> >> Do you think that we need to have an API in LinkingContext to return the >> next ordinal available, so that files created by passes can be assigned >> ordinals ? >> > That API may work, but I

...6-32, x86-64 and aarch64) in assembly refers to a > function whose address can be insignificant. The assembler produces an > R_386_PLT32/R_X86_64_PLT32/R_AARCH64_PLT32 relocation which will be > resolved by the linker to either: > > * the definition (non-preemptible (logical AND (non-ifunc or ld.lld -z ifunc- > noplt is specified))) > * a PLT entry (other cases) > > The address can be insignificant: ultimately the program will call the > function. There is no difference if the program calls the function > directly or calls through one PLT entry in any module (execut...

...; wrote: >> >> I'm not there yet, but at some point I'm going to need the notion of a >> global callable function like symbol that's resolved at runtime. I've >> not given it much thought but I may need a new callable entity here >> (this is for the gnu ifunc stuff). >> >> Don't even know if this fits into the discussion, but since we were >> talking about weird symbols... >> > > It is a symbol or a value that is loaded? If it is an symbol, what does it point to? That is, what is the value that shows up in the .o? Relo...

Hi, I've been using rsync (OSX Tiger now Leopard) to backup my home folder daily using -a -H -A -X link-dest=dir to make incremental backups. There was a problem though since many files especially images, movies etc would be recopied each time instead of creating hard links. I have been testing the pre5 release and found that it seems to make hard links correctly for all files. I