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