From d8f6d5cdd7114f8e31f75f76752738170e83c8e9 Mon Sep 17 00:00:00 2001 From: Nico Weber Date: Wed, 6 Jan 2016 19:05:19 +0000 Subject: [PATCH] Make WinCOFFObjectWriter.cpp's timestamp writing not use ENABLE_TIMESTAMPS MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit LLVM_ENABLE_TIMESTAMPS controls if timestamps are embedded into llvm's binaries. Turning it off is useful for deterministic builds. r246905 made it so that the define suddenly also controls if the binaries that the llvm binaries _create_ embed timestamps or not – but this shouldn't be a configure-time option. r256203/r256204 added a driver option to toggle this on and off, so this patch now passes this driver option in LLVM_ENABLE_TIMESTAMPS builds so that if LLVM_ENABLE_TIMESTAMPS is set, the build of LLVM is deterministic – but the built clang can still write timestamps into other executables when requested. This also allows removing some of the test machinery added in r292012 to work around this problem. See PR24740 for background. http://reviews.llvm.org/D15783 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256958 91177308-0d34-0410-b5e6-96231b3b80d8 --- cmake/modules/HandleLLVMOptions.cmake | 30 +++++++++++++++++++++++++++ lib/MC/WinCOFFObjectWriter.cpp | 8 +------ test/MC/COFF/timestamp.s | 1 - test/lit.cfg | 4 ---- test/lit.site.cfg.in | 1 - 5 files changed, 31 insertions(+), 13 deletions(-) diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake index 4c5ffe2f7b2..6db258ff66a 100644 --- a/cmake/modules/HandleLLVMOptions.cmake +++ b/cmake/modules/HandleLLVMOptions.cmake @@ -363,6 +363,36 @@ if( MSVC ) append("/Zc:inline" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) + if (NOT LLVM_ENABLE_TIMESTAMPS AND CMAKE_CXX_COMPILER_ID MATCHES "Clang") + # clang-cl and cl by default produce non-deterministic binaries because + # link.exe /incremental requires a timestamp in the .obj file. clang-cl + # has the flag /Brepro to force deterministic binaries, so pass that when + # LLVM_ENABLE_TIMESTAMPS is turned off. + # This checks CMAKE_CXX_COMPILER_ID in addition to check_cxx_compiler_flag() + # because cl.exe does not emit an error on flags it doesn't understand, + # letting check_cxx_compiler_flag() claim it understands all flags. + check_cxx_compiler_flag("/Brepro" SUPPORTS_BREPRO) + append_if(SUPPORTS_BREPRO "/Brepro" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) + + if (SUPPORTS_BREPRO) + # Check if /INCREMENTAL is passed to the linker and complain that it + # won't work with /Brepro. + string(TOUPPER "${CMAKE_EXE_LINKER_FLAGS}" upper_exe_flags) + string(TOUPPER "${CMAKE_MODULE_LINKER_FLAGS}" upper_module_flags) + string(TOUPPER "${CMAKE_SHARED_LINKER_FLAGS}" upper_shared_flags) + + string(FIND "${upper_exe_flags}" "/INCREMENTAL" exe_index) + string(FIND "${upper_module_flags}" "/INCREMENTAL" module_index) + string(FIND "${upper_shared_flags}" "/INCREMENTAL" shared_index) + + if (${exe_index} GREATER -1 OR + ${module_index} GREATER -1 OR + ${shared_index} GREATER -1) + message(FATAL_ERROR "LLVM_ENABLE_TIMESTAMPS not compatible with /INCREMENTAL linking") + endif() + endif() + endif() + # Disable sized deallocation if the flag is supported. MSVC fails to compile # the operator new overload in User otherwise. check_c_compiler_flag("/WX /Zc:sizedDealloc-" SUPPORTS_SIZED_DEALLOC) diff --git a/lib/MC/WinCOFFObjectWriter.cpp b/lib/MC/WinCOFFObjectWriter.cpp index a3820906b76..a76cbdbd544 100644 --- a/lib/MC/WinCOFFObjectWriter.cpp +++ b/lib/MC/WinCOFFObjectWriter.cpp @@ -969,9 +969,6 @@ void WinCOFFObjectWriter::writeObject(MCAssembler &Asm, Header.PointerToSymbolTable = offset; - // FIXME: Remove the #else branch and make the #if branch unconditional once - // LLVM's self host configuration is aware of /Brepro. -#if (ENABLE_TIMESTAMPS == 1) // MS LINK expects to be able to use this timestamp to implement their // /INCREMENTAL feature. if (Asm.isIncrementalLinkerCompatible()) { @@ -980,12 +977,9 @@ void WinCOFFObjectWriter::writeObject(MCAssembler &Asm, Now = UINT32_MAX; Header.TimeDateStamp = Now; } else { + // Have deterministic output if /INCREMENTAL isn't needed. Also matches GNU. Header.TimeDateStamp = 0; } -#else - // We want a deterministic output. It looks like GNU as also writes 0 in here. - Header.TimeDateStamp = 0; -#endif // Write it all to disk... WriteFileHeader(Header); diff --git a/test/MC/COFF/timestamp.s b/test/MC/COFF/timestamp.s index a2761575789..140225acf7e 100644 --- a/test/MC/COFF/timestamp.s +++ b/test/MC/COFF/timestamp.s @@ -1,5 +1,4 @@ // RUN: llvm-mc -filetype=obj -triple i686-pc-win32 -incremental-linker-compatible %s -o - | llvm-readobj -h | FileCheck %s -// REQUIRES: timestamps // CHECK: ImageFileHeader { // CHECK: TimeDateStamp: diff --git a/test/lit.cfg b/test/lit.cfg index 36b4c704408..5cc4d6e0456 100644 --- a/test/lit.cfg +++ b/test/lit.cfg @@ -459,10 +459,6 @@ if platform.system() in ['Windows'] and re.match(r'.*-win32$', config.target_tri if not re.match(r'^x86_64.*-(mingw32|windows-gnu|win32)', config.target_triple): config.available_features.add('debug_frame') -# Check if we are embedding timestamps. -if config.enable_timestamps == '1': - config.available_features.add('timestamps') - # Check if we should use gmalloc. use_gmalloc_str = lit_config.params.get('use_gmalloc', None) if use_gmalloc_str is not None: diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in index ae5814f02f4..13f5372ef7e 100644 --- a/test/lit.site.cfg.in +++ b/test/lit.site.cfg.in @@ -36,7 +36,6 @@ config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@" config.have_zlib = "@HAVE_LIBZ@" config.have_dia_sdk = @HAVE_DIA_SDK@ config.enable_ffi = "@LLVM_ENABLE_FFI@" -config.enable_timestamps = "@ENABLE_TIMESTAMPS@" config.test_examples = "@ENABLE_EXAMPLES@" # Support substitution of the tools_dir with user parameters. This is -- 2.34.1