{-# LANGUAGE ScopedTypeVariables #-} {- ----------------------------------------------------------------------------- -- -- (c) The University of Glasgow 2001-2003 -- -- Access to system tools: gcc, cp, rm etc -- ----------------------------------------------------------------------------- -} module GHC.SysTools ( -- * Initialisation initSysTools, lazyInitLlvmConfig, -- * Interface to system tools module GHC.SysTools.Tasks, module GHC.SysTools.Info, -- * Fast file copy copyFile, copyHandle, copyWithHeader, -- * General utilities Option(..), expandTopDir, ) where import GHC.Prelude import GHC.Settings.Utils import GHC.Utils.Panic import GHC.Driver.Session import GHC.Linker.ExtraObj import GHC.SysTools.Info import GHC.SysTools.Tasks import GHC.SysTools.BaseDir import GHC.Settings.IO import Control.Monad.Trans.Except (runExceptT) import System.FilePath import System.IO import System.IO.Unsafe (unsafeInterleaveIO) import Foreign.Marshal.Alloc (allocaBytes) import System.Directory (copyFile) {- Note [How GHC finds toolchain utilities] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC.SysTools.initSysProgs figures out exactly where all the auxiliary programs are, and initialises mutable variables to make it easy to call them. To do this, it makes use of definitions in Config.hs, which is a Haskell file containing variables whose value is figured out by the build system. Config.hs contains two sorts of things cGCC, The *names* of the programs cCPP e.g. cGCC = gcc cUNLIT cCPP = gcc -E etc They do *not* include paths cUNLIT_DIR The *path* to the directory containing unlit, split etc cSPLIT_DIR *relative* to the root of the build tree, for use when running *in-place* in a build tree (only) --------------------------------------------- NOTES for an ALTERNATIVE scheme (i.e *not* what is currently implemented): Another hair-brained scheme for simplifying the current tool location nightmare in GHC: Simon originally suggested using another configuration file along the lines of GCC's specs file - which is fine except that it means adding code to read yet another configuration file. What I didn't notice is that the current package.conf is general enough to do this: Package {name = "tools", import_dirs = [], source_dirs = [], library_dirs = [], hs_libraries = [], extra_libraries = [], include_dirs = [], c_includes = [], package_deps = [], extra_ghc_opts = ["-pgmc/usr/bin/gcc","-pgml${topdir}/bin/unlit", ... etc.], extra_cc_opts = [], extra_ld_opts = []} Which would have the advantage that we get to collect together in one place the path-specific package stuff with the path-specific tool stuff. End of NOTES --------------------------------------------- ************************************************************************ * * \subsection{Initialisation} * * ************************************************************************ -} -- Note [LLVM configuration] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- The `llvm-targets` and `llvm-passes` files are shipped with GHC and contain -- information needed by the LLVM backend to invoke `llc` and `opt`. -- Specifically: -- -- * llvm-targets maps autoconf host triples to the corresponding LLVM -- `data-layout` declarations. This information is extracted from clang using -- the script in utils/llvm-targets/gen-data-layout.sh and should be updated -- whenever we target a new version of LLVM. -- -- * llvm-passes maps GHC optimization levels to sets of LLVM optimization -- flags that GHC should pass to `opt`. -- -- This information is contained in files rather the GHC source to allow users -- to add new targets to GHC without having to recompile the compiler. -- -- Since this information is only needed by the LLVM backend we load it lazily -- with unsafeInterleaveIO. Consequently it is important that we lazily pattern -- match on LlvmConfig until we actually need its contents. lazyInitLlvmConfig :: String -> IO LlvmConfig lazyInitLlvmConfig top_dir = unsafeInterleaveIO $ do -- see Note [LLVM configuration] targets <- readAndParse "llvm-targets" passes <- readAndParse "llvm-passes" return $ LlvmConfig { llvmTargets = fmap mkLlvmTarget <$> targets, llvmPasses = passes } where readAndParse :: Read a => String -> IO a readAndParse name = do let llvmConfigFile = top_dir name llvmConfigStr <- readFile llvmConfigFile case maybeReadFuzzy llvmConfigStr of Just s -> return s Nothing -> pgmError ("Can't parse " ++ show llvmConfigFile) mkLlvmTarget :: (String, String, String) -> LlvmTarget mkLlvmTarget (dl, cpu, attrs) = LlvmTarget dl cpu (words attrs) initSysTools :: String -- TopDir path -> IO Settings -- Set all the mutable variables above, holding -- (a) the system programs -- (b) the package-config file -- (c) the GHC usage message initSysTools top_dir = do res <- runExceptT $ initSettings top_dir case res of Right a -> pure a Left (SettingsError_MissingData msg) -> pgmError msg Left (SettingsError_BadData msg) -> pgmError msg {- Note [Windows stack allocations] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ See: #8870 (and #8834 for related info) and #12186 On Windows, occasionally we need to grow the stack. In order to do this, we would normally just bump the stack pointer - but there's a catch on Windows. If the stack pointer is bumped by more than a single page, then the pages between the initial pointer and the resulting location must be properly committed by the Windows virtual memory subsystem. This is only needed in the event we bump by more than one page (i.e 4097 bytes or more). Windows compilers solve this by emitting a call to a special function called _chkstk, which does this committing of the pages for you. The reason this was causing a segfault was because due to the fact the new code generator tends to generate larger functions, we needed more stack space in GHC itself. In the x86 codegen, we needed approximately ~12kb of stack space in one go, which caused the process to segfault, as the intervening pages were not committed. GCC can emit such a check for us automatically but only when the flag -fstack-check is used. See https://gcc.gnu.org/onlinedocs/gnat_ugn/Stack-Overflow-Checking.html for more information. -} -- | Copy remaining bytes from the first Handle to the second one copyHandle :: Handle -> Handle -> IO () copyHandle hin hout = do let buf_size = 8192 allocaBytes buf_size $ \ptr -> do let go = do c <- hGetBuf hin ptr buf_size hPutBuf hout ptr c if c == 0 then return () else go go -- | Copy file after printing the given header copyWithHeader :: String -> FilePath -> FilePath -> IO () copyWithHeader header from to = withBinaryFile to WriteMode $ \hout -> do -- write the header string in UTF-8. The header is something like -- {-# LINE "foo.hs" #-} -- and we want to make sure a Unicode filename isn't mangled. hSetEncoding hout utf8 hPutStr hout header withBinaryFile from ReadMode $ \hin -> copyHandle hin hout