similar to: [LLVMdev] [RFC] Exhaustive bitcode compatibility tests for IR features

> On Sep 19, 2014, at 9:57 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote: > > So the proposal is that during development new features are added to > test/Features/compatibility.ll (or some other name). When 3.6 is > released, we will > > * assemble the file with llvm-as-3.6. > * Check in the .bc file as test/Features/Input/compatibility-3.6.bc > *

This sounds like a good plan. Initially, the tests will be very repetitious, but over time as we make changes they will diverge. For example, before swapping the order of 'alias' and linkage in the IL, we would've had: @a = alias weak i8* @target ; CHECK: @a = alias weak i8* @target This would've been copied to compatibility-3.N.ll for the previous release before the change, and

It sounds like the Android RenderScript guys have the most in-the-trenches experience with bitcode incompatibilities. Stephen Hines (CC'd), what sorts of incompatibilities have you guys seen during the 3.x timeline? Would Steven Wu's proposal catch the sorts of incompatibilities that you guys have seen? -- Sean Silva On Thu, Nov 6, 2014 at 4:38 PM, Steven Wu <stevenwu at apple.com>

Hello, A strange problem appears when upgrading from release_34 to testing. Some transformations to bitcode files cause registered global_ctors to not be called. Here's an example (I've also attached the complete example and pasted it below): This works: clang -fsanitize=address -flto -c -o sum.o sum.c clang -fsanitize=address -o sum sum.o This doesn't work: clang

Can anyone explain how llc translates "appending linkage" global variables like llvm.global_ctors into assembly? In the case I am examining, the global_ctor variables are in multiple bitcode object modules produced by the llvm compiler as arrays of pointers. As documented, the arrays seem to be combined when the different bitcode object modules are linked into one, so now there is one

Hi, I'm running LLVM bitcode generated by my compiler under lli. The bitcode is linked against Boehm GC (lli -load=/usr/lib/libgc.so). It looks like Boehm GC isn't scanning global variables and as a result objects referenced only through globals are being prematurely collected. I understand that Boehm GC needs to see the data segment containing my global variables as a root. For native

A recent commit added the ability to opt and llc to read .ll files directly. Should we go through and update the existing tests? llvm-as < %s | opt ... | llvm-dis would become: opt %s ... -print-module and llvm-as < %s | llc would become: llc < %s The pro of this is that it would remove the bitcode write and read from the tests, making them faster. The con of this is

I've implemented this by adding calls to GC_add_roots(<first global in module>,<last global in module>+1) to the llvm.global_ctors before any other static initialization code for the module. This should be safe assuming that: - global variables are laid out in memory in the order they appear in their module (and ideally contiguously without being interleaved with any other values)

On Wed, Jul 30, 2014 at 3:46 PM, Rafael Espíndola < rafael.espindola at gmail.com> wrote: > > Looking a little deeper, it's not "old-style" exactly; rejecting this > > isn't trivial. > > > > - According to LangRef, the third field is optional [1]. > > > > [1]: > http://llvm.org/docs/LangRef.html#the-llvm-global-ctors-global-variable

You should look at http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ExecutionEngine/JITMemoryManager.h?view=markup and see if inheriting from that and overriding allocateGlobal() will do what you want. I'm a little surprised the boehm gc doesn't already see the globals, since there's a reference to their memory from the JMM, but maybe it doesn't scan mmap regions by

+reid, +llvmdev, -llvm-commits > On 2014-Jul-30, at 11:56, Rafael Avila de Espindola <rafael.espindola at gmail.com> wrote: > > >> I think the fix is to upgrade old-style global arrays (or reject >> them?) in the .ll parser. >> > > The .ll format is not stable, so you should be able to just reject it. Looking a little deeper, it's not

On Tue, Feb 18, 2020 at 9:42 PM David Blaikie <dblaikie at gmail.com> wrote: > I'm /guessing/ this might be related to the COFF support specifically > (perhaps COFF has no appending linkage support - in some cases LLVM IR > supports the union of all semantics so that different formats can be fully > expressed - but it means when targeting certain formats, some features are

On 10 Sep 2015, at 10:09, serge guelton via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > On Thu, Sep 10, 2015 at 04:20:01PM +0800, Dipanjan Das via llvm-dev wrote: >> Hello, >> >> I can see the occurrences of several LLVM intrinsic functions in the LLVM >> IR generated by llvm-dis disassembler. Is there any means to rewrite these >> functions

Thanks for the hindsight. I am currently working on a patch/potential fix which introduces a new Linker::ImportIntrinsicGlobalVariables flag. The patch includes a unit test reproducing the problem. Hopefully, that will help getting more feedback. Note that it might take a while before I am allowed to upload the patch since I need approval from Autodesk Legal department. Cheers, Benoit Benoit

> On 2014-Jul-30, at 18:05, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote: > >> On 2014-Jul-30, at 17:19, Reid Kleckner <rnk at google.com> wrote: >> >>> On Wed, Jul 30, 2014 at 3:46 PM, Rafael Espíndola <rafael.espindola at gmail.com> wrote: >>>> Looking a little deeper, it's not "old-style" exactly; rejecting this

Thanks Peter, this is very useful feedback. I did manage to change the behavior of LinkOnlyNeeded to correctly import all variables with AppendingLinkage. In fact, I discovered that there was already something fishy. A variable with AppendingLinkage would get imported correctly from the source module if the destination module already contained a definition for that variable and wouldn't be

Hi Everyone, We are looking for advise regarding the proper use of LTO in conjunction with just-in time generated code. Our usage scenario goes as follows. 1. Our front-end generates an LLVM module. 2. A small runtime support library is linked-in. The runtime library is distributed as bitcode. It is generated using "clang++ -emit-llvm' and 'llvm-link'. This allows

> On 2014-Jul-31, at 10:07, Reid Kleckner <rnk at google.com> wrote: > >> On Thu, Jul 31, 2014 at 9:49 AM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote: >> Hold on, I'm still not sure what kind of guarantees (restrictions) the C >> API imposes. >> >> If I implement (2), then -verify will fail if someone (e.g.) adds >>

The debug information is actually still in a different format in the .bc file, it is LLVM metadata. I think the best reference for it is here: https://llvm.org/docs/SourceLevelDebugging.html#ccxx-frontend You can dump it just by disassembling the .bc file to textual IR using llvm-dis and examining the !DI* metadata nodes. You will have to run the file through llc to generate an object file to

I have a problem. I'm writing a C compiler in my favorite programming language (don't ask :-) I have made a .s file, which can be correctly assembled and run with lli. But when I optimize it I get no errors from the optimizer, but the resultant file is incorrect. Here's what happens: llvm-as test2_gen.s %% no errors test2_gen.s.bc is produced lli test2_gen.s.bc n=887459712