src/librustc_codegen_llvm/llvm_util.rs

   1 use crate::back::write::create_informational_target_machine;
   2 use crate::llvm;
   3 use syntax_pos::symbol::Symbol;
   4 use rustc::session::Session;
   5 use rustc::session::config::PrintRequest;
   6 use rustc_data_structures::fx::FxHashSet;
   7 use rustc_target::spec::{MergeFunctions, PanicStrategy};
   8 use libc::c_int;
   9 use std::ffi::CString;
  10 use rustc_feature::UnstableFeatures;
  11 use syntax::symbol::sym;
  12 use rustc::bug;
  13
  14 use std::str;
  15 use std::slice;
  16 use std::sync::atomic::{AtomicBool, Ordering};
  17 use std::sync::Once;
  18
  19 static POISONED: AtomicBool = AtomicBool::new(false);
  20 static INIT: Once = Once::new();
  21
  22 pub(crate) fn init(sess: &Session) {
  23     unsafe {
  24         // Before we touch LLVM, make sure that multithreading is enabled.
  25         INIT.call_once(|| {
  26             if llvm::LLVMStartMultithreaded() != 1 {
  27                 // use an extra bool to make sure that all future usage of LLVM
  28                 // cannot proceed despite the Once not running more than once.
  29                 POISONED.store(true, Ordering::SeqCst);
  30             }
  31
  32             configure_llvm(sess);
  33         });
  34
  35         if POISONED.load(Ordering::SeqCst) {
  36             bug!("couldn't enable multi-threaded LLVM");
  37         }
  38     }
  39 }
  40
  41 fn require_inited() {
  42     INIT.call_once(|| bug!("llvm is not initialized"));
  43     if POISONED.load(Ordering::SeqCst) {
  44         bug!("couldn't enable multi-threaded LLVM");
  45     }
  46 }
  47
  48 unsafe fn configure_llvm(sess: &Session) {
  49     let n_args = sess.opts.cg.llvm_args.len();
  50     let mut llvm_c_strs = Vec::with_capacity(n_args + 1);
  51     let mut llvm_args = Vec::with_capacity(n_args + 1);
  52
  53     llvm::LLVMRustInstallFatalErrorHandler();
  54
  55     fn llvm_arg_to_arg_name(full_arg: &str) -> &str {
  56         full_arg.trim().split(|c: char| {
  57             c == '=' || c.is_whitespace()
  58         }).next().unwrap_or("")
  59     }
  60
  61     let user_specified_args: FxHashSet<_> = sess
  62         .opts
  63         .cg
  64         .llvm_args
  65         .iter()
  66         .map(|s| llvm_arg_to_arg_name(s))
  67         .filter(|s| s.len() > 0)
  68         .collect();
  69
  70     {
  71         // This adds the given argument to LLVM. Unless `force` is true
  72         // user specified arguments are *not* overridden.
  73         let mut add = |arg: &str, force: bool| {
  74             if force || !user_specified_args.contains(llvm_arg_to_arg_name(arg)) {
  75                 let s = CString::new(arg).unwrap();
  76                 llvm_args.push(s.as_ptr());
  77                 llvm_c_strs.push(s);
  78             }
  79         };
  80         add("rustc", true); // fake program name
  81         if sess.time_llvm_passes() { add("-time-passes", false); }
  82         if sess.print_llvm_passes() { add("-debug-pass=Structure", false); }
  83
  84         if sess.opts.debugging_opts.generate_arange_section {
  85             add("-generate-arange-section", false);
  86         }
  87         if get_major_version() >= 8 {
  88             match sess.opts.debugging_opts.merge_functions
  89                   .unwrap_or(sess.target.target.options.merge_functions) {
  90                 MergeFunctions::Disabled |
  91                 MergeFunctions::Trampolines => {}
  92                 MergeFunctions::Aliases => {
  93                     add("-mergefunc-use-aliases", false);
  94                 }
  95             }
  96         }
  97
  98         if sess.target.target.target_os == "emscripten" &&
  99             sess.panic_strategy() == PanicStrategy::Unwind {
 100             add("-enable-emscripten-cxx-exceptions", false);
 101         }
 102
 103         // HACK(eddyb) LLVM inserts `llvm.assume` calls to preserve align attributes
 104         // during inlining. Unfortunately these may block other optimizations.
 105         add("-preserve-alignment-assumptions-during-inlining=false", false);
 106
 107         for arg in &sess.opts.cg.llvm_args {
 108             add(&(*arg), true);
 109         }
 110     }
 111
 112     llvm::LLVMInitializePasses();
 113
 114     ::rustc_llvm::initialize_available_targets();
 115
 116     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
 117                                  llvm_args.as_ptr());
 118 }
 119
 120 // WARNING: the features after applying `to_llvm_feature` must be known
 121 // to LLVM or the feature detection code will walk past the end of the feature
 122 // array, leading to crashes.
 123
 124 const ARM_WHITELIST: &[(&str, Option<Symbol>)] = &[
 125     ("aclass", Some(sym::arm_target_feature)),
 126     ("mclass", Some(sym::arm_target_feature)),
 127     ("rclass", Some(sym::arm_target_feature)),
 128     ("dsp", Some(sym::arm_target_feature)),
 129     ("neon", Some(sym::arm_target_feature)),
 130     ("crc", Some(sym::arm_target_feature)),
 131     ("crypto", Some(sym::arm_target_feature)),
 132     ("v5te", Some(sym::arm_target_feature)),
 133     ("v6", Some(sym::arm_target_feature)),
 134     ("v6k", Some(sym::arm_target_feature)),
 135     ("v6t2", Some(sym::arm_target_feature)),
 136     ("v7", Some(sym::arm_target_feature)),
 137     ("v8", Some(sym::arm_target_feature)),
 138     ("vfp2", Some(sym::arm_target_feature)),
 139     ("vfp3", Some(sym::arm_target_feature)),
 140     ("vfp4", Some(sym::arm_target_feature)),
 141 ];
 142
 143 const AARCH64_WHITELIST: &[(&str, Option<Symbol>)] = &[
 144     ("fp", Some(sym::aarch64_target_feature)),
 145     ("neon", Some(sym::aarch64_target_feature)),
 146     ("sve", Some(sym::aarch64_target_feature)),
 147     ("crc", Some(sym::aarch64_target_feature)),
 148     ("crypto", Some(sym::aarch64_target_feature)),
 149     ("ras", Some(sym::aarch64_target_feature)),
 150     ("lse", Some(sym::aarch64_target_feature)),
 151     ("rdm", Some(sym::aarch64_target_feature)),
 152     ("fp16", Some(sym::aarch64_target_feature)),
 153     ("rcpc", Some(sym::aarch64_target_feature)),
 154     ("dotprod", Some(sym::aarch64_target_feature)),
 155     ("v8.1a", Some(sym::aarch64_target_feature)),
 156     ("v8.2a", Some(sym::aarch64_target_feature)),
 157     ("v8.3a", Some(sym::aarch64_target_feature)),
 158 ];
 159
 160 const X86_WHITELIST: &[(&str, Option<Symbol>)] = &[
 161     ("adx", Some(sym::adx_target_feature)),
 162     ("aes", None),
 163     ("avx", None),
 164     ("avx2", None),
 165     ("avx512bw", Some(sym::avx512_target_feature)),
 166     ("avx512cd", Some(sym::avx512_target_feature)),
 167     ("avx512dq", Some(sym::avx512_target_feature)),
 168     ("avx512er", Some(sym::avx512_target_feature)),
 169     ("avx512f", Some(sym::avx512_target_feature)),
 170     ("avx512ifma", Some(sym::avx512_target_feature)),
 171     ("avx512pf", Some(sym::avx512_target_feature)),
 172     ("avx512vbmi", Some(sym::avx512_target_feature)),
 173     ("avx512vl", Some(sym::avx512_target_feature)),
 174     ("avx512vpopcntdq", Some(sym::avx512_target_feature)),
 175     ("bmi1", None),
 176     ("bmi2", None),
 177     ("cmpxchg16b", Some(sym::cmpxchg16b_target_feature)),
 178     ("f16c", Some(sym::f16c_target_feature)),
 179     ("fma", None),
 180     ("fxsr", None),
 181     ("lzcnt", None),
 182     ("mmx", Some(sym::mmx_target_feature)),
 183     ("movbe", Some(sym::movbe_target_feature)),
 184     ("pclmulqdq", None),
 185     ("popcnt", None),
 186     ("rdrand", None),
 187     ("rdseed", None),
 188     ("rtm", Some(sym::rtm_target_feature)),
 189     ("sha", None),
 190     ("sse", None),
 191     ("sse2", None),
 192     ("sse3", None),
 193     ("sse4.1", None),
 194     ("sse4.2", None),
 195     ("sse4a", Some(sym::sse4a_target_feature)),
 196     ("ssse3", None),
 197     ("tbm", Some(sym::tbm_target_feature)),
 198     ("xsave", None),
 199     ("xsavec", None),
 200     ("xsaveopt", None),
 201     ("xsaves", None),
 202 ];
 203
 204 const HEXAGON_WHITELIST: &[(&str, Option<Symbol>)] = &[
 205     ("hvx", Some(sym::hexagon_target_feature)),
 206     ("hvx-length128b", Some(sym::hexagon_target_feature)),
 207 ];
 208
 209 const POWERPC_WHITELIST: &[(&str, Option<Symbol>)] = &[
 210     ("altivec", Some(sym::powerpc_target_feature)),
 211     ("power8-altivec", Some(sym::powerpc_target_feature)),
 212     ("power9-altivec", Some(sym::powerpc_target_feature)),
 213     ("power8-vector", Some(sym::powerpc_target_feature)),
 214     ("power9-vector", Some(sym::powerpc_target_feature)),
 215     ("vsx", Some(sym::powerpc_target_feature)),
 216 ];
 217
 218 const MIPS_WHITELIST: &[(&str, Option<Symbol>)] = &[
 219     ("fp64", Some(sym::mips_target_feature)),
 220     ("msa", Some(sym::mips_target_feature)),
 221 ];
 222
 223 const WASM_WHITELIST: &[(&str, Option<Symbol>)] = &[
 224     ("simd128", Some(sym::wasm_target_feature)),
 225     ("atomics", Some(sym::wasm_target_feature)),
 226 ];
 227
 228 /// When rustdoc is running, provide a list of all known features so that all their respective
 229 /// primitives may be documented.
 230 ///
 231 /// IMPORTANT: If you're adding another whitelist to the above lists, make sure to add it to this
 232 /// iterator!
 233 pub fn all_known_features() -> impl Iterator<Item=(&'static str, Option<Symbol>)> {
 234     ARM_WHITELIST.iter().cloned()
 235         .chain(AARCH64_WHITELIST.iter().cloned())
 236         .chain(X86_WHITELIST.iter().cloned())
 237         .chain(HEXAGON_WHITELIST.iter().cloned())
 238         .chain(POWERPC_WHITELIST.iter().cloned())
 239         .chain(MIPS_WHITELIST.iter().cloned())
 240         .chain(WASM_WHITELIST.iter().cloned())
 241 }
 242
 243 pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
 244     let arch = if sess.target.target.arch == "x86_64" {
 245         "x86"
 246     } else {
 247         &*sess.target.target.arch
 248     };
 249     match (arch, s) {
 250         ("x86", "pclmulqdq") => "pclmul",
 251         ("x86", "rdrand") => "rdrnd",
 252         ("x86", "bmi1") => "bmi",
 253         ("x86", "cmpxchg16b") => "cx16",
 254         ("aarch64", "fp") => "fp-armv8",
 255         ("aarch64", "fp16") => "fullfp16",
 256         (_, s) => s,
 257     }
 258 }
 259
 260 pub fn target_features(sess: &Session) -> Vec<Symbol> {
 261     let target_machine = create_informational_target_machine(sess, true);
 262     target_feature_whitelist(sess)
 263         .iter()
 264         .filter_map(|&(feature, gate)| {
 265             if UnstableFeatures::from_environment().is_nightly_build() || gate.is_none() {
 266                 Some(feature)
 267             } else {
 268                 None
 269             }
 270         })
 271         .filter(|feature| {
 272             let llvm_feature = to_llvm_feature(sess, feature);
 273             let cstr = CString::new(llvm_feature).unwrap();
 274             unsafe { llvm::LLVMRustHasFeature(target_machine, cstr.as_ptr()) }
 275         })
 276         .map(|feature| Symbol::intern(feature)).collect()
 277 }
 278
 279 pub fn target_feature_whitelist(sess: &Session)
 280     -> &'static [(&'static str, Option<Symbol>)]
 281 {
 282     match &*sess.target.target.arch {
 283         "arm" => ARM_WHITELIST,
 284         "aarch64" => AARCH64_WHITELIST,
 285         "x86" | "x86_64" => X86_WHITELIST,
 286         "hexagon" => HEXAGON_WHITELIST,
 287         "mips" | "mips64" => MIPS_WHITELIST,
 288         "powerpc" | "powerpc64" => POWERPC_WHITELIST,
 289         "wasm32" => WASM_WHITELIST,
 290         _ => &[],
 291     }
 292 }
 293
 294 pub fn print_version() {
 295     // Can be called without initializing LLVM
 296     unsafe {
 297         println!("LLVM version: {}.{}",
 298                  llvm::LLVMRustVersionMajor(), llvm::LLVMRustVersionMinor());
 299     }
 300 }
 301
 302 pub fn get_major_version() -> u32 {
 303     unsafe { llvm::LLVMRustVersionMajor() }
 304 }
 305
 306 pub fn print_passes() {
 307     // Can be called without initializing LLVM
 308     unsafe { llvm::LLVMRustPrintPasses(); }
 309 }
 310
 311 pub(crate) fn print(req: PrintRequest, sess: &Session) {
 312     require_inited();
 313     let tm = create_informational_target_machine(sess, true);
 314     unsafe {
 315         match req {
 316             PrintRequest::TargetCPUs => llvm::LLVMRustPrintTargetCPUs(tm),
 317             PrintRequest::TargetFeatures => llvm::LLVMRustPrintTargetFeatures(tm),
 318             _ => bug!("rustc_codegen_llvm can't handle print request: {:?}", req),
 319         }
 320     }
 321 }
 322
 323 pub fn target_cpu(sess: &Session) -> &str {
 324     let name = match sess.opts.cg.target_cpu {
 325         Some(ref s) => &**s,
 326         None => &*sess.target.target.options.cpu
 327     };
 328     if name != "native" {
 329         return name
 330     }
 331
 332     unsafe {
 333         let mut len = 0;
 334         let ptr = llvm::LLVMRustGetHostCPUName(&mut len);
 335         str::from_utf8(slice::from_raw_parts(ptr as *const u8, len)).unwrap()
 336     }
 337 }