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