LLVM/Polly build configurations

[Michael Kruse]

Hi,

I tried which build configurations for Polly currently work and which don't which what reason. I thought this might be useful information to see whether new patches (such as D51963) regress and/or to know what needs to be fixed.  The version of LLVM/Polly used is r342650. I looked at 18 different build configurations.

 

Legend:

	All test pass
	Partially works
	Doesn’t work

 

GNU/WSL

	LLVM_POLLY_LINK_INTO_TOOLS=1	LLVM_POLLY_LINK_INTO_TOOLS=0	Out-of-source-tree
Static link		(1)	(1)
BUILD_SHARED_LIBS=1			(2)
LLVM_LINK_LLVM_DYLIB=1

 

Windows (msvc)

	LLVM_POLLY_LINK_INTO_TOOLS=1	LLVM_POLLY_LINK_INTO_TOOLS=0	Out-of-source-tree
Static link		(3)
BUILD_SHARED_LIBS=1	(4)
LLVM_LINK_LLVM_DYLIB=1	(5)

 

(1)         opt: symbol lookup error: /home/meinersbur/build/polly/release_static/lib/LLVMPolly.so: undefined symbol: _ZN4llvm4json5parseENS_9StringRefE

 

The JSON parser is not used in LLVM, so the symbols from Support/JSON.cpp are not in the opt executable.

JSON is only needed for some regression tests, the others work.

 

(2)    Undefined references to gtest when linking unit tests

but “opt -load LLVMPolly.so” works

(3)    -load mechanism cannot work on windows since library imports need to specify which library they are importing from (so LLVMPolly.so would need to know whether e.g. it is loaded into opt or clang)

(4)         LINK : fatal error LNK1181: cannot open input file 'lib\LLVMDemangle.lib'

 

Not supported according to http://lists.llvm.org/pipermail/llvm-dev/2018-September/126173.html

 

(5)    CMake Error at tools/llvm-shlib/CMakeLists.txt:15 (message):

  Generating libLLVM is not supported on MSVC

 

 Michael

[Tobias Grosser]

I feel we should drop support for everything except LLVM_POLLY_LINK_INTO_TOOLS=1.

Best,
Tobias

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[Philip Pfaffe]

I strongly disagree in general, because that breaks essentially all downstream users. That being said, I'm fine with dropping the support on Windows (native). LLVM itself doesn't support plugins on windows, so there's no point in supporting this in polly.

[Tobias Grosser]

Philip, you have a valid point. Could we then maybe may make sure to either get a clear error message for unsupported configurations (windows) or get the configurations green?

I feel for windows we could just report that this is a unsupported configuration. For linux, maybe we don't include the JSON import/export in case we build a plugin? For (2) we could also report an error that unit tests are not supported in this configuration?

Best,
Tobias

[Michael Kruse]

Am Fr., 28. Sep. 2018 um 09:13 Uhr schrieb Tobias Grosser
<tobias....@inf.ethz.ch>:

> I feel for windows we could just report that this is a unsupported configuration. For linux, maybe we don't include the JSON import/export in case we build a plugin? For (2) we could also report an error that unit tests are not supported in this configuration?

It might be easy to fix (2) depending on why the linking fails. For
instance, it could be because more c/.cpp have been added to newer
versions to gtest. Haven't looked into the why.

Michael

[Philip Pfaffe]

Micheal,

Can you share the exact steps configurations for (1) and (2), or a Dockerfile to reproduce this?

Cheers,

Philip

[Michael Kruse]

Did you have problems reproducing the configurations? Setting the
cmake definitions should be sufficient.

Anyway, here are the configurations that I used:

The scripts assume to be in ~/build/llvm (respectively ~/build/polly)
and the llvm source in ~/src/llvm with clang/polly checked-out
(respectively ~/src/polly). You can either put them in the same path,
create a symlink to the real path or change the script.

(1) [LLVM_POLLY_LINK_INTO_TOOLS=0]

$ cd ~/build/llvm
$ ./release_static_loadpolly.sh
$ cd release_static_loadpolly
$ ninja check-polly

(2)

$ cd ~/build/llvm
$ ./release_shared_nopolly.sh
$ cd release_shared_nopolly
$ ninja install
$ cd ~/build/polly
$ ./release_shared.sh
$ cd release_shared
$ ninja check-polly

Michael
Am So., 30. Sep. 2018 um 04:55 Uhr schrieb Philip Pfaffe
<philip...@gmail.com>:

[Michael Kruse]

I re-did the same test for Linux again (for  https://reviews.llvm.org/D61446) with the results below. The reason for (2) has changed. I split the out-of-source configurations into LLVM_DIR either pointing to LLVM's build directory and LLVM's install prefix (after filling it with ninja install).

		Works
		partially works
		broken
Linux
	LLVM_POLLY_LINK_INTO_TOOLS=1	LLVM_POLLY_LINK_INTO_TOOLS=0	Out-of-source-tree: builddir	Out-of-source-tree: installdir
Static link		(1)	(1)	(1)
BUILD_SHARED_LIBS=1				(2)
LLVM_LINK_LLVM_DYLIB=1

(1) Failing Tests (1):     Polly :: GPGPU/libdevice-functions-copied-into-kernel.ll GPGPU/libdevice-functions-copied-into-kernel.ll fails: LLVMPolly.so: undefined symbol: _ZN4llvm6LinkerC1ERNS_6ModuleE The llvm::Linker class is not used inside opt, such that the object file LinkModules.o is not included in the opt executable. A fix is available here:  https://reviews.llvm.org/D65295

(2)

Undefined references to gtest when linking unit tests

However, "clang -Xclang -load -Xclang LLVMPolly.so" works Michael