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