[PATCH] D85627: [polly][cmake] Don't build LLVMPolly.so without PIC

Mon Aug 10 00:18:49 PDT 2020

ro created this revision.
ro added a reviewer: grosser.
ro added a project: Polly.
Herald added subscribers: llvm-commits, fedor.sergeev, mgorny, jyknight.
Herald added a reviewer: bollu.
Herald added a project: LLVM.
ro requested review of this revision.

A build on `sparcv9-sun-solaris2.11` with `-DLLVM_ENABLE_PIC=Off` failed linking `LLVMPolly.so`:

  [2277/2297] Linking CXX shared module lib/LLVMPolly.so
  FAILED: lib/LLVMPolly.so
  [...]
  ld: fatal: relocation error: R_SPARC_H44: file tools/polly/lib/CMakeFiles/obj.Polly.dir/Analysis/DependenceInfo.cpp.o: symbol .data._ZL16__gthread_active (section): invalid shared object relocation type: ABS44 code model unsupported
  [...]

As on many other targets, one cannot link non-PIC objects into a shared object on Solaris/sparcv9.

The following patch avoids this by not building the library without PIC.  It allowed the build to finish.

Testing showed one regression however:

  FAIL: Polly :: Isl/isl-args.ll (66183 of 67884)
  [...]
  Command Output (stderr):
  --
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
  Stack dump:
  0.      Program arguments: opt -polly-process-unprofitable -polly-remarks-minimal -polly-use-llvm-names -polly-import-jscop-dir=/vol/llvm/src/llvm-project/dist/polly/test/Isl -polly-codegen-verify -polly-scops -disable-output -polly-isl-arg=-h
  1.      Running pass 'Function Pass Manager' on module '<stdin>'.
  2.      Running pass 'Region Pass Manager' on function '@foo_1d'
  3.      Running pass 'Polly - Create polyhedral description of Scops' on basic block '%bb1'
  0  opt       0x000000010460fb70 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 20
  1  opt       0x000000010460e650 SignalHandler(int) + 420
  2  libc.so.1 0xffffffff7eedc800 __sighndlr + 12
  3  libc.so.1 0xffffffff7eecf23c call_user_handler + 852
  4  libc.so.1 0xffffffff7eecf594 sigacthandler + 84
  5  libc.so.1 0xffffffff7edecd50 strlen + 80
  6  libc.so.1 0xffffffff7ee4d28c _ndoprnt + 20
  7  libc.so.1 0xffffffff7ee4c110 printf + 272
  8  opt       0x0000000105208814 print_bool_help + 308
  9  opt       0x0000000105209e70 isl_args_parse + 1764
  10 opt       0x0000000104f36310 polly::Scop::Scop(llvm::Region&, llvm::ScalarEvolution&, llvm::LoopInfo&, llvm::DominatorTree&, polly::ScopDetection::DetectionContext&, llvm::OptimizationRemarkEmitter&, int) + 692
  11 opt       0x0000000104f69b50 polly::ScopBuilder::buildScop(llvm::Region&, llvm::AssumptionCache&) + 80
  12 opt       0x0000000104f6ada0 polly::ScopBuilder::ScopBuilder(llvm::Region*, llvm::AssumptionCache&, llvm::AAResults&, llvm::DataLayout const&, llvm::DominatorTree&, llvm::LoopInfo&, polly::ScopDetection&, llvm::ScalarEvolution&, llvm::OptimizationRemarkEmitter&) + 588
  13 opt       0x0000000104f37400 polly::ScopInfoRegionPass::runOnRegion(llvm::Region*, llvm::RGPassManager&) + 744
  14 opt       0x00000001036beda8 llvm::RGPassManager::runOnFunction(llvm::Function&) + 3172
  15 opt       0x0000000103dd1c18 llvm::FPPassManager::runOnFunction(llvm::Function&) + 1084
  16 opt       0x0000000103dd32e0 llvm::FPPassManager::runOnModule(llvm::Module&) + 32
  17 opt       0x0000000103dd0ee0 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 1440
  18 opt       0x00000001021070ac main + 9856
  19 opt       0x00000001020e6864 _start + 100

`gdb` shows that `strlen` incurred a `SEGV` which is usually a sign of calling it with `NULL`.  Debugging that requires a `Debug` build which I don't currently have the time and disk space to try.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85627

Files:
  polly/CMakeLists.txt
  polly/cmake/CMakeLists.txt
  polly/lib/CMakeLists.txt


Index: polly/lib/CMakeLists.txt
===================================================================

--- polly/lib/CMakeLists.txt
+++ polly/lib/CMakeLists.txt
@@ -137,7 +137,7 @@
 
 # Create a loadable module Polly.so that can be loaded using
 # LLVM's/clang's "-load" option.
-if (MSVC)
+if (MSVC OR NOT LLVM_ENABLE_PIC)
   # Add dummy target, because loadable modules are not supported on Windows
   add_custom_target(LLVMPolly)
   set_target_properties(LLVMPolly PROPERTIES FOLDER "Polly")
Index: polly/cmake/CMakeLists.txt
===================================================================
--- polly/cmake/CMakeLists.txt
+++ polly/cmake/CMakeLists.txt
@@ -10,7 +10,7 @@
 endif()
 
 set(POLLY_CONFIG_EXPORTED_TARGETS Polly ${ISL_TARGET})
-if (NOT MSVC)
+if (NOT MSVC AND LLVM_ENABLE_PIC)
   # LLVMPolly is a dummy target on Win
   list(APPEND POLLY_CONFIG_EXPORTED_TARGETS LLVMPolly)
 endif()
Index: polly/CMakeLists.txt
===================================================================
--- polly/CMakeLists.txt
+++ polly/CMakeLists.txt
@@ -58,8 +58,10 @@
     endif()
   endif()
 
-  # Make sure the isl c files are built as fPIC
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
+  if (LLVM_ENABLE_PIC)
+    # Make sure the isl c files are built as fPIC
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
+  endif ()
 
   # Set directory for polly-isl-test.
   set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin")


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