From 9f6b5327a4691ba91c7ecbd4d8fb5b685af01d2e Mon Sep 17 00:00:00 2001 From: Rainer Orth Date: Fri, 28 Aug 2020 11:40:34 +0200 Subject: [PATCH] [cmake] Don't build with -O3 -fPIC on Solaris/sparcv9 Tests on Solaris/sparcv9 currently show about 250 failures when building with gcc, 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 > >::_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` It has meanwhile been determined that `gcc` doesn't correctly heed some TLS code sequences. To make things worse, Solaris `ld` doesn't properly validate its assumptions against the input, generating wrong code. `gld` like `gcc` is more liberal here and correctly deals with the code it gets fed from `gcc`. There's PR target/96607: GCC feeds SPARC/Solaris linker with unrecognized TLS sequences now. An attempt to build with `-DLLVM_ENABLE_PIC=Off` initially failed since neither `libRemarks.so` (D85626 ) nor `LLVMPolly.so` (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` and `RelWithDebInfo` builds. As detailed in Bug 47304, 2-stage builds also show large numbers of failures when building with `-O3` or `-O2`, which are likewise worked around by building with `-O` until they are sufficiently analyzed and fixed. This way, all failures relative to a `Debug` build go away. Tested on `sparcv9-sun-solaris2.11`. Differential Revision: https://reviews.llvm.org/D85630 (cherry picked from commit 15c66b10114d239c96282cf8fc5330186178974b) --- cmake/modules/HandleLLVMOptions.cmake | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake index 2e249593e12..5ef22eb493b 100644 --- a/cmake/modules/HandleLLVMOptions.cmake +++ b/cmake/modules/HandleLLVMOptions.cmake @@ -12,6 +12,7 @@ include(CheckCCompilerFlag) 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) @@ -291,6 +292,15 @@ if( LLVM_ENABLE_PIC ) NOT Uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG") add_flag_or_print_warning("-fno-shrink-wrap" FNO_SHRINK_WRAP) endif() + # gcc with -O3 -fPIC generates TLS sequences that violate the spec on + # Solaris/sparcv9, causing executables created with the system linker + # to SEGV (GCC PR target/96607). + # clang with -O3 -fPIC generates code that SEGVs. + # Both can be worked around by compiling with -O instead. + if(${CMAKE_SYSTEM_NAME} STREQUAL "SunOS" AND LLVM_NATIVE_ARCH STREQUAL "Sparc") + llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O[23]" "-O") + llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O[23]" "-O") + endif() endif() if(NOT WIN32 AND NOT CYGWIN AND NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX" AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU"))