[PATCH] D85630: [cmake] Don't build with -O3 -fPIC on Solaris/sparcv9

[Rainer Orth via Phabricator via llvm-commits]

ro created this revision.
ro added reviewers: chandlerc, daltenty, tstellar, hans, serge-sans-paille.
Herald added subscribers: fedor.sergeev, mgorny, jyknight.
Herald added a reviewer: bollu.
Herald added a project: LLVM.
ro requested review of this revision.

Tests on Solaris/sparcv9 currently show about 250 failures, most of them like the following:

  FAIL: LLVM-Unit :: Support/./SupportTests/TaskQueueTest.UnOrderedFutures (4269 of 67884)
  ******************** TEST 'LLVM-Unit :: Support/./SupportTests/TaskQueueTest.UnOrderedFutures' FAILED ********************
  Note: Google Test filter = TaskQueueTest.UnOrderedFutures
  [==========] Running 1 test from 1 test case.
  [----------] Global test environment set-up.
  [----------] 1 test from TaskQueueTest
  [ RUN      ] TaskQueueTest.UnOrderedFutures
  0  SupportTests        0x0000000100753b20 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 32
  1  SupportTests        0x0000000100752974 llvm::sys::RunSignalHandlers() + 68
  2  SupportTests        0x0000000100752b18 SignalHandler(int) + 372
  3  libc.so.1           0xffffffff7eedc800 __sighndlr + 12
  4  libc.so.1           0xffffffff7eecf23c call_user_handler + 852
  5  libc.so.1           0xffffffff7eecf594 sigacthandler + 84
  6  SupportTests        0x00000001006f8cb8 std::thread::_State_impl<std::thread::_Invoker<std::tuple<llvm::ThreadPool::ThreadPool(llvm::ThreadPoolStrategy)::'lambda'()> > >::_M_run() + 512
  7  libstdc++.so.6.0.28 0xfffffffc628117cc execute_native_thread_routine + 16
  8  libc.so.1           0xffffffff7eedc6a0 _lwp_start + 0

Since it's effectively impossible to debug such a `SEGV` in a `Release` build, I tried a `Debug` build instead, only to find that the failures had gone away.

Further investigation revealed that most of the issue centers around `llvm/lib/Support/ThreadPool.cpp`.  That file is built with `-O3 -fPIC` in a `Release` build.  The failure vanishes if

- compiling without `-fPIC`
- compiling with `-O -fPIC`
- linking with GNU `ld` instead of Solaris `ld`

An attempt to build with `-DLLVM_ENABLE_PIC=Off` initially failed since neither `libRemarks.so` (D85626 <https://reviews.llvm.org/D85626>) nor `LLVMPolly.so` (D85627 <https://reviews.llvm.org/D85627>) heed that option.  Even with that fixed, a few codegen failures remain.

Next I tried to build just `ThreadPool.cpp` with `-O -fPIC`.  While that fixed the vast majority of the failures, 16 `LLVM :: CodeGen/X86` failures remained.

Given that that solution was both incomplete and fragile, I went for building the whole tree with `-O -fPIC` for `Release` builds.

This is what this patch does, making all failures relative to a `Debug` build go away.

Tested on `sparcv9-sun-solaris2.11`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85630

Files:
  llvm/cmake/modules/HandleLLVMOptions.cmake


Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -12,6 +12,7 @@
 include(CheckCXXCompilerFlag)
 include(CheckSymbolExists)
 include(CMakeDependentOption)
+include(LLVMProcessSources)
 
 if(CMAKE_LINKER MATCHES "lld-link" OR (MSVC AND (LLVM_USE_LINKER STREQUAL "lld" OR LLVM_ENABLE_LLD)))
   set(LINKER_IS_LLD_LINK TRUE)
@@ -296,6 +297,14 @@
          NOT Uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     add_flag_or_print_warning("-fno-shrink-wrap" FNO_SHRINK_WRAP)
   endif()
+  # When g++ builds with -O3 -fPIC on Solaris/sparcv9, executables created
+  # with the system linker SEGV.
+  if(CMAKE_COMPILER_IS_GNUCXX AND
+     ${CMAKE_SYSTEM_NAME} STREQUAL "SunOS" AND
+     LLVM_NATIVE_ARCH STREQUAL "Sparc" AND
+     NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+     llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O")
+  endif()
 endif()
 
 if(NOT WIN32 AND NOT CYGWIN AND NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX" AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU"))


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