doesn't work with llvm 3.5.0

[pranavk]

code gives seg fault when run with llvm 3.5.0

[shamsuddin508]

use it in llvm 3.4.2

[pranavk]

I think that was probably because the binaries and the source code in which we put the llvm passes need to be the same version.

[pranavk]

I realised that there are some changes in LLVM version 3.5.0 and I think this code needs to be changed so that it works with LLVM 3.5.0.

hence, i am reopening this issue until it compiles with 3.5.0

[pranavk]

port branch taking care of the port to 3.5.0.

I have already tested it and it compiles successfuly. Few more days and we will merge it to master.

[pranavk]

There is a problem of infinite loop and then eventually segmentation fault.

From the stack trace it seems that it is all because of improper data structure used. Probably we need to do something more efficient.

Here is the stack trace :

0 opt 0x0000000000fdd155 llvm::sys::PrintStackTrace(IO_FILE) + 37
1 opt 0x0000000000fdd5a3
2 libpthread.so.0 0x00007f6c0b9fa0d0
3 opt 0x0000000000fe21a3 llvm::StringMapImpl::FindKey(llvm::StringRef) const + 67
4 opt 0x0000000000fe22a4 llvm::StringMapImpl::RemoveKey(llvm::StringMapEntryBase_) + 20
5 opt 0x0000000000f950c1 llvm::Value::setName(llvm::Twine const&) + 465
6 Spatial.so 0x00007f6c0a9f5389 WaveScalar::init(llvm::Function const&) + 489
7 Spatial.so 0x00007f6c0a9f4f6c WaveScalar::annotateWaves(llvm::Function const&, llvm::SmallVectorImpl<std::pair<llvm::BasicBlock const*, llvm::BasicBlock const*> >*) + 44
8 Spatial.so 0x00007f6c0a9f45a8
9 opt 0x0000000000f81fab llvm::FPPassManager::runOnFunction(llvm::Function&) + 315
10 opt 0x0000000000f8216b llvm::FPPassManager::runOnModule(llvm::Module&) + 43
11 opt 0x0000000000f825cb llvm::legacy::PassManagerImpl::run(llvm::Module&) + 859
12 opt 0x00000000005616bc main + 7004
13 libc.so.6 0x00007f6c0ac1afe0 __libc_start_main + 240
14 opt 0x000000000055d0b1

[shashagit]

I am not able to replicate this issue. Instead I get the correct output on the terminal followed by this error:

LLVM ERROR: IO failure on output stream.

Also the dfg.dot that this is generating does not seem correct.

[pranavk]

"LLVM ERROR: IO failure on output stream."

is there because you are not using "-o" flag with opt to output the bitcode file. When -o flag is not used, it means that it will output the bitcode format on standard output stream which is the reason of IO failure by LLVM in this case.

I am able to resolve this issue easily by using -o flag with opt when executing pases.

[pranavk]

After some more investigation, I think the culprit is FindFunctionBackedges function that I used in waves.cpp.

If I comment that line, it obviously gives wrong information about waves and wave annotation is done wrongly but it doesn't output any error.

If you are able to solve this problem with above solution too, please let me know.

[shashagit]

Commenting FindFunctionBackedges clears out the seg faults. Nice observation!