Auto merge of #30417 - alexcrichton:better-detect-elf-tls, r=alexcrichton
Currently a compiler can be built with the `--disable-elf-tls` option for compatibility with OSX 10.6 which doesn't have ELF TLS. This is unfortunate, however, as a whole new compiler must be generated which can take some time. These commits add a new (feature gated) `cfg(target_thread_local)` annotation set by the compiler which indicates whether `#[thread_local]` is available for use. The compiler now interprets `MACOSX_DEPLOYMENT_TARGET` (a standard environment variable) to set this flag on OSX. With this we may want to start compiling our OSX nightlies with `MACOSX_DEPLOYMENT_TARGET` set to 10.6 which would allow the compiler out-of-the-box to generate 10.6-compatible binaries. For now the compiler still by default targets OSX 10.7 by allowing ELF TLS by default (e.g. if `MACOSX_DEPLOYMENT_TARGET` isn't set).
This commit is contained in:
commit
42c3ef8f9f
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@ -660,6 +660,9 @@ pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
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"windows" | "unix" => ret.push(attr::mk_word_item(fam)),
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_ => (),
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}
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if sess.target.target.options.has_elf_tls {
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ret.push(attr::mk_word_item(InternedString::new("target_thread_local")));
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}
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if sess.opts.debug_assertions {
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ret.push(attr::mk_word_item(InternedString::new("debug_assertions")));
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}
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|
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@ -11,7 +11,8 @@
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use target::Target;
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pub fn target() -> Target {
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let base = super::linux_base::opts();
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let mut base = super::linux_base::opts();
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base.has_elf_tls = false;
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Target {
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llvm_target: "aarch64-unknown-linux-gnu".to_string(),
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target_endian: "little".to_string(),
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@ -8,10 +8,30 @@
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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 std::env;
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use target::TargetOptions;
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use std::default::Default;
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pub fn opts() -> TargetOptions {
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// ELF TLS is only available in OSX 10.7+. If you try to compile for 10.6
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// either the linker will complain if it is used or the binary will end up
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// segfaulting at runtime when run on 10.6. Rust by default supports OSX
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// 10.7+, but there is a standard environment variable,
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// MACOSX_DEPLOYMENT_TARGET, which is used to signal targeting older
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// versions of OSX. For example compiling on 10.10 with
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// MACOSX_DEPLOYMENT_TARGET set to 10.6 will cause the linker to generate
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// warnings about the usage of ELF TLS.
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//
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// Here we detect what version is being requested, defaulting to 10.7. ELF
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// TLS is flagged as enabled if it looks to be supported.
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let deployment_target = env::var("MACOSX_DEPLOYMENT_TARGET").ok();
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let version = deployment_target.as_ref().and_then(|s| {
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let mut i = s.splitn(2, ".");
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i.next().and_then(|a| i.next().map(|b| (a, b)))
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}).and_then(|(a, b)| {
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a.parse::<u32>().and_then(|a| b.parse::<u32>().map(|b| (a, b))).ok()
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}).unwrap_or((10, 7));
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TargetOptions {
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// OSX has -dead_strip, which doesn't rely on ffunction_sections
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function_sections: false,
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@ -25,6 +45,7 @@ pub fn opts() -> TargetOptions {
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archive_format: "bsd".to_string(),
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pre_link_args: Vec::new(),
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exe_allocation_crate: super::maybe_jemalloc(),
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has_elf_tls: version >= (10, 7),
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.. Default::default()
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}
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}
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|
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@ -88,6 +88,7 @@ pub fn opts(arch: Arch) -> TargetOptions {
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dynamic_linking: false,
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executables: true,
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pre_link_args: pre_link_args(arch),
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has_elf_tls: false,
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.. super::apple_base::opts()
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}
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}
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@ -13,6 +13,7 @@ use target::Target;
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pub fn target() -> Target {
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let mut base = super::android_base::opts();
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base.features = "+v7".to_string();
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base.has_elf_tls = false;
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Target {
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llvm_target: "arm-linux-androideabi".to_string(),
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@ -30,6 +30,7 @@ pub fn opts() -> TargetOptions {
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position_independent_executables: true,
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archive_format: "gnu".to_string(),
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exe_allocation_crate: super::maybe_jemalloc(),
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has_elf_tls: true,
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.. Default::default()
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}
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}
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|
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@ -195,6 +195,10 @@ pub struct TargetOptions {
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/// Default crate for allocation symbols to link against
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pub lib_allocation_crate: String,
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pub exe_allocation_crate: String,
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/// Flag indicating whether ELF TLS (e.g. #[thread_local]) is available for
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/// this target.
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pub has_elf_tls: bool,
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}
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impl Default for TargetOptions {
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@ -240,6 +244,7 @@ impl Default for TargetOptions {
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lib_allocation_crate: "alloc_system".to_string(),
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exe_allocation_crate: "alloc_system".to_string(),
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allow_asm: true,
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has_elf_tls: false,
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}
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}
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}
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|
|
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@ -606,7 +606,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
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feature_gated_cfgs.sort();
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feature_gated_cfgs.dedup();
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for cfg in &feature_gated_cfgs {
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cfg.check_and_emit(sess.diagnostic(), &features);
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cfg.check_and_emit(sess.diagnostic(), &features, sess.codemap());
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}
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});
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|
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@ -218,6 +218,7 @@
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#![feature(borrow_state)]
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#![feature(box_syntax)]
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#![feature(cfg_target_vendor)]
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#![feature(cfg_target_thread_local)]
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#![feature(char_internals)]
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#![feature(clone_from_slice)]
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#![feature(collections)]
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|
|
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@ -15,10 +15,6 @@
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use cell::UnsafeCell;
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use mem;
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// Sure wish we had macro hygiene, no?
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#[doc(hidden)]
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pub use self::imp::Key as __KeyInner;
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/// A thread local storage key which owns its contents.
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///
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/// This key uses the fastest possible implementation available to it for the
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@ -61,41 +57,27 @@ pub use self::imp::Key as __KeyInner;
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/// });
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct LocalKey<T:'static> {
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// The key itself may be tagged with #[thread_local], and this `Key` is
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// stored as a `static`, and it's not valid for a static to reference the
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// address of another thread_local static. For this reason we kinda wonkily
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// work around this by generating a shim function which will give us the
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// address of the inner TLS key at runtime.
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pub struct LocalKey<T: 'static> {
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// This outer `LocalKey<T>` type is what's going to be stored in statics,
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// but actual data inside will sometimes be tagged with #[thread_local].
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// It's not valid for a true static to reference a #[thread_local] static,
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// so we get around that by exposing an accessor through a layer of function
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// indirection (this thunk).
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//
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// This is trivially devirtualizable by LLVM because we never store anything
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// to this field and rustc can declare the `static` as constant as well.
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inner: fn() -> &'static __KeyInner<T>,
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// Note that the thunk is itself unsafe because the returned lifetime of the
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// slot where data lives, `'static`, is not actually valid. The lifetime
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// here is actually `'thread`!
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//
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// Although this is an extra layer of indirection, it should in theory be
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// trivially devirtualizable by LLVM because the value of `inner` never
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// changes and the constant should be readonly within a crate. This mainly
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// only runs into problems when TLS statics are exported across crates.
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inner: unsafe fn() -> Option<&'static UnsafeCell<Option<T>>>,
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// initialization routine to invoke to create a value
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init: fn() -> T,
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}
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// Macro pain #4586:
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//
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// When cross compiling, rustc will load plugins and macros from the *host*
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// platform before search for macros from the target platform. This is primarily
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// done to detect, for example, plugins. Ideally the macro below would be
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// defined once per module below, but unfortunately this means we have the
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// following situation:
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//
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// 1. We compile libstd for x86_64-unknown-linux-gnu, this thread_local!() macro
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// will inject #[thread_local] statics.
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// 2. We then try to compile a program for arm-linux-androideabi
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// 3. The compiler has a host of linux and a target of android, so it loads
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// macros from the *linux* libstd.
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// 4. The macro generates a #[thread_local] field, but the android libstd does
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// not use #[thread_local]
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// 5. Compile error about structs with wrong fields.
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//
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// To get around this, we're forced to inject the #[cfg] logic into the macro
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// itself. Woohoo.
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/// Declare a new thread local storage key of type `std::thread::LocalKey`.
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///
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/// See [LocalKey documentation](thread/struct.LocalKey.html) for more
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@ -103,36 +85,14 @@ pub struct LocalKey<T:'static> {
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#[macro_export]
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#[stable(feature = "rust1", since = "1.0.0")]
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#[allow_internal_unstable]
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#[cfg(not(no_elf_tls))]
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macro_rules! thread_local {
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(static $name:ident: $t:ty = $init:expr) => (
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static $name: $crate::thread::LocalKey<$t> =
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__thread_local_inner!($t, $init,
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#[cfg_attr(all(any(target_os = "macos", target_os = "linux"),
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not(target_arch = "aarch64")),
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thread_local)]);
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__thread_local_inner!($t, $init);
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);
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(pub static $name:ident: $t:ty = $init:expr) => (
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pub static $name: $crate::thread::LocalKey<$t> =
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__thread_local_inner!($t, $init,
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#[cfg_attr(all(any(target_os = "macos", target_os = "linux"),
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not(target_arch = "aarch64")),
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thread_local)]);
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);
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}
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#[macro_export]
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#[stable(feature = "rust1", since = "1.0.0")]
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#[allow_internal_unstable]
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#[cfg(no_elf_tls)]
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macro_rules! thread_local {
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(static $name:ident: $t:ty = $init:expr) => (
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static $name: $crate::thread::LocalKey<$t> =
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__thread_local_inner!($t, $init, #[]);
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);
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(pub static $name:ident: $t:ty = $init:expr) => (
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pub static $name: $crate::thread::LocalKey<$t> =
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__thread_local_inner!($t, $init, #[]);
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__thread_local_inner!($t, $init);
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);
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}
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|
@ -143,12 +103,25 @@ macro_rules! thread_local {
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#[macro_export]
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#[allow_internal_unstable]
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macro_rules! __thread_local_inner {
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($t:ty, $init:expr, #[$($attr:meta),*]) => {{
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$(#[$attr])*
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static __KEY: $crate::thread::__LocalKeyInner<$t> =
|
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$crate::thread::__LocalKeyInner::new();
|
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($t:ty, $init:expr) => {{
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fn __init() -> $t { $init }
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fn __getit() -> &'static $crate::thread::__LocalKeyInner<$t> { &__KEY }
|
||||
|
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unsafe fn __getit() -> $crate::option::Option<
|
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&'static $crate::cell::UnsafeCell<
|
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$crate::option::Option<$t>>>
|
||||
{
|
||||
#[thread_local]
|
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#[cfg(target_thread_local)]
|
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static __KEY: $crate::thread::__ElfLocalKeyInner<$t> =
|
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$crate::thread::__ElfLocalKeyInner::new();
|
||||
|
||||
#[cfg(not(target_thread_local))]
|
||||
static __KEY: $crate::thread::__OsLocalKeyInner<$t> =
|
||||
$crate::thread::__OsLocalKeyInner::new();
|
||||
|
||||
__KEY.get()
|
||||
}
|
||||
|
||||
$crate::thread::LocalKey::new(__getit, __init)
|
||||
}}
|
||||
}
|
||||
|
@ -190,11 +163,11 @@ impl<T: 'static> LocalKey<T> {
|
|||
#[unstable(feature = "thread_local_internals",
|
||||
reason = "recently added to create a key",
|
||||
issue = "0")]
|
||||
pub const fn new(inner: fn() -> &'static __KeyInner<T>,
|
||||
pub const fn new(inner: unsafe fn() -> Option<&'static UnsafeCell<Option<T>>>,
|
||||
init: fn() -> T) -> LocalKey<T> {
|
||||
LocalKey {
|
||||
inner: inner,
|
||||
init: init
|
||||
init: init,
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -211,10 +184,10 @@ impl<T: 'static> LocalKey<T> {
|
|||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
pub fn with<F, R>(&'static self, f: F) -> R
|
||||
where F: FnOnce(&T) -> R {
|
||||
let slot = (self.inner)();
|
||||
unsafe {
|
||||
let slot = slot.get().expect("cannot access a TLS value during or \
|
||||
after it is destroyed");
|
||||
let slot = (self.inner)();
|
||||
let slot = slot.expect("cannot access a TLS value during or \
|
||||
after it is destroyed");
|
||||
f(match *slot.get() {
|
||||
Some(ref inner) => inner,
|
||||
None => self.init(slot),
|
||||
|
@ -270,7 +243,7 @@ impl<T: 'static> LocalKey<T> {
|
|||
issue = "27716")]
|
||||
pub fn state(&'static self) -> LocalKeyState {
|
||||
unsafe {
|
||||
match (self.inner)().get() {
|
||||
match (self.inner)() {
|
||||
Some(cell) => {
|
||||
match *cell.get() {
|
||||
Some(..) => LocalKeyState::Valid,
|
||||
|
@ -283,11 +256,9 @@ impl<T: 'static> LocalKey<T> {
|
|||
}
|
||||
}
|
||||
|
||||
#[cfg(all(any(target_os = "macos", target_os = "linux"),
|
||||
not(target_arch = "aarch64"),
|
||||
not(no_elf_tls)))]
|
||||
#[cfg(target_thread_local)]
|
||||
#[doc(hidden)]
|
||||
mod imp {
|
||||
pub mod elf {
|
||||
use cell::{Cell, UnsafeCell};
|
||||
use intrinsics;
|
||||
use ptr;
|
||||
|
@ -431,11 +402,8 @@ mod imp {
|
|||
}
|
||||
}
|
||||
|
||||
#[cfg(any(not(any(target_os = "macos", target_os = "linux")),
|
||||
target_arch = "aarch64",
|
||||
no_elf_tls))]
|
||||
#[doc(hidden)]
|
||||
mod imp {
|
||||
pub mod os {
|
||||
use prelude::v1::*;
|
||||
|
||||
use cell::{Cell, UnsafeCell};
|
||||
|
|
|
@ -191,7 +191,10 @@ pub use self::local::{LocalKey, LocalKeyState};
|
|||
pub use self::scoped_tls::ScopedKey;
|
||||
|
||||
#[unstable(feature = "libstd_thread_internals", issue = "0")]
|
||||
#[doc(hidden)] pub use self::local::__KeyInner as __LocalKeyInner;
|
||||
#[cfg(target_thread_local)]
|
||||
#[doc(hidden)] pub use self::local::elf::Key as __ElfLocalKeyInner;
|
||||
#[unstable(feature = "libstd_thread_internals", issue = "0")]
|
||||
#[doc(hidden)] pub use self::local::os::Key as __OsLocalKeyInner;
|
||||
#[unstable(feature = "libstd_thread_internals", issue = "0")]
|
||||
#[doc(hidden)] pub use self::scoped_tls::__KeyInner as __ScopedKeyInner;
|
||||
|
||||
|
|
|
@ -236,6 +236,9 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Option<u32>, Status
|
|||
|
||||
// allow using type ascription in expressions
|
||||
("type_ascription", "1.6.0", Some(23416), Active),
|
||||
|
||||
// Allows cfg(target_thread_local)
|
||||
("cfg_target_thread_local", "1.7.0", Some(29594), Active),
|
||||
];
|
||||
// (changing above list without updating src/doc/reference.md makes @cmr sad)
|
||||
|
||||
|
@ -414,6 +417,8 @@ const GATED_CFGS: &'static [(&'static str, &'static str, fn(&Features) -> bool)]
|
|||
// (name in cfg, feature, function to check if the feature is enabled)
|
||||
("target_feature", "cfg_target_feature", cfg_fn!(|x| x.cfg_target_feature)),
|
||||
("target_vendor", "cfg_target_vendor", cfg_fn!(|x| x.cfg_target_vendor)),
|
||||
("target_thread_local", "cfg_target_thread_local",
|
||||
cfg_fn!(|x| x.cfg_target_thread_local)),
|
||||
];
|
||||
|
||||
#[derive(Debug, Eq, PartialEq)]
|
||||
|
@ -449,10 +454,13 @@ impl PartialOrd for GatedCfgAttr {
|
|||
}
|
||||
|
||||
impl GatedCfgAttr {
|
||||
pub fn check_and_emit(&self, diagnostic: &Handler, features: &Features) {
|
||||
pub fn check_and_emit(&self,
|
||||
diagnostic: &Handler,
|
||||
features: &Features,
|
||||
codemap: &CodeMap) {
|
||||
match *self {
|
||||
GatedCfgAttr::GatedCfg(ref cfg) => {
|
||||
cfg.check_and_emit(diagnostic, features);
|
||||
cfg.check_and_emit(diagnostic, features, codemap);
|
||||
}
|
||||
GatedCfgAttr::GatedAttr(span) => {
|
||||
if !features.stmt_expr_attributes {
|
||||
|
@ -479,9 +487,12 @@ impl GatedCfg {
|
|||
}
|
||||
})
|
||||
}
|
||||
fn check_and_emit(&self, diagnostic: &Handler, features: &Features) {
|
||||
fn check_and_emit(&self,
|
||||
diagnostic: &Handler,
|
||||
features: &Features,
|
||||
codemap: &CodeMap) {
|
||||
let (cfg, feature, has_feature) = GATED_CFGS[self.index];
|
||||
if !has_feature(features) {
|
||||
if !has_feature(features) && !codemap.span_allows_unstable(self.span) {
|
||||
let explain = format!("`cfg({})` is experimental and subject to change", cfg);
|
||||
emit_feature_err(diagnostic, feature, self.span, GateIssue::Language, &explain);
|
||||
}
|
||||
|
@ -541,6 +552,7 @@ pub struct Features {
|
|||
pub type_macros: bool,
|
||||
pub cfg_target_feature: bool,
|
||||
pub cfg_target_vendor: bool,
|
||||
pub cfg_target_thread_local: bool,
|
||||
pub augmented_assignments: bool,
|
||||
pub braced_empty_structs: bool,
|
||||
pub staged_api: bool,
|
||||
|
@ -575,6 +587,7 @@ impl Features {
|
|||
type_macros: false,
|
||||
cfg_target_feature: false,
|
||||
cfg_target_vendor: false,
|
||||
cfg_target_thread_local: false,
|
||||
augmented_assignments: false,
|
||||
braced_empty_structs: false,
|
||||
staged_api: false,
|
||||
|
@ -1157,6 +1170,7 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &Handler,
|
|||
type_macros: cx.has_feature("type_macros"),
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cfg_target_feature: cx.has_feature("cfg_target_feature"),
|
||||
cfg_target_vendor: cx.has_feature("cfg_target_vendor"),
|
||||
cfg_target_thread_local: cx.has_feature("cfg_target_thread_local"),
|
||||
augmented_assignments: cx.has_feature("augmented_assignments"),
|
||||
braced_empty_structs: cx.has_feature("braced_empty_structs"),
|
||||
staged_api: cx.has_feature("staged_api"),
|
||||
|
|
Loading…
Reference in New Issue