80 lines
3.3 KiB
Rust
80 lines
3.3 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use syntax::ast;
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use llvm::LLVMRustHasFeature;
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use rustc::session::Session;
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use rustc_trans::back::write::create_target_machine;
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use syntax::feature_gate::UnstableFeatures;
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use syntax::symbol::Symbol;
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use libc::c_char;
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// WARNING: the features must be known to LLVM or the feature
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// detection code will walk past the end of the feature array,
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// leading to crashes.
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const ARM_WHITELIST: &'static [&'static str] = &["neon\0", "vfp2\0", "vfp3\0", "vfp4\0"];
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const X86_WHITELIST: &'static [&'static str] = &["avx\0", "avx2\0", "bmi\0", "bmi2\0", "sse\0",
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"sse2\0", "sse3\0", "sse4.1\0", "sse4.2\0",
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"ssse3\0", "tbm\0", "lzcnt\0", "popcnt\0",
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"sse4a\0", "rdrnd\0", "rdseed\0", "fma\0"];
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/// Add `target_feature = "..."` cfgs for a variety of platform
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/// specific features (SSE, NEON etc.).
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///
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/// This is performed by checking whether a whitelisted set of
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/// features is available on the target machine, by querying LLVM.
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pub fn add_configuration(cfg: &mut ast::CrateConfig, sess: &Session) {
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let target_machine = create_target_machine(sess);
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let whitelist = match &*sess.target.target.arch {
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"arm" => ARM_WHITELIST,
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"x86" | "x86_64" => X86_WHITELIST,
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_ => &[],
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};
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let tf = Symbol::intern("target_feature");
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for feat in whitelist {
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assert_eq!(feat.chars().last(), Some('\0'));
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if unsafe { LLVMRustHasFeature(target_machine, feat.as_ptr() as *const c_char) } {
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cfg.insert((tf, Some(Symbol::intern(&feat[..feat.len() - 1]))));
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}
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}
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let requested_features = sess.opts.cg.target_feature.split(',');
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let unstable_options = sess.opts.debugging_opts.unstable_options;
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let is_nightly = UnstableFeatures::from_environment().is_nightly_build();
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let found_negative = requested_features.clone().any(|r| r == "-crt-static");
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let found_positive = requested_features.clone().any(|r| r == "+crt-static");
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// If the target we're compiling for requests a static crt by default,
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// then see if the `-crt-static` feature was passed to disable that.
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// Otherwise if we don't have a static crt by default then see if the
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// `+crt-static` feature was passed.
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let crt_static = if sess.target.target.options.crt_static_default {
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!found_negative
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} else {
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found_positive
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};
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// If we switched from the default then that's only allowed on nightly, so
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// gate that here.
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if (found_positive || found_negative) && (!is_nightly || !unstable_options) {
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sess.fatal("specifying the `crt-static` target feature is only allowed \
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on the nightly channel with `-Z unstable-options` passed \
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as well");
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}
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if crt_static {
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cfg.insert((tf, Some(Symbol::intern("crt-static"))));
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}
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}
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