211 lines
7.6 KiB
Diff
211 lines
7.6 KiB
Diff
From 0f5ee28213a73733e6811b176c89ecececfe9cbc Mon Sep 17 00:00:00 2001
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From: bors <bors@rust-lang.org>
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Date: Mon, 11 Sep 2017 12:53:21 +0000
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Subject: [PATCH] Auto merge of #44440 - cuviper:min_global_align,
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r=japaric
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Add `TargetOptions::min_global_align`, with s390x at 16-bit
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The SystemZ `LALR` instruction provides PC-relative addressing for globals,
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but only to *even* addresses, so other compilers make sure that such
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globals are always 2-byte aligned. In Clang, this is modeled with
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`TargetInfo::MinGlobalAlign`, and `TargetOptions::min_global_align` now
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serves the same purpose for rustc.
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In Clang, the only targets that set this are SystemZ, Lanai, and NVPTX, and
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the latter two don't have targets in rust master.
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Fixes #44411.
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r? @eddyb
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---
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src/librustc_back/target/mod.rs | 6 ++++
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.../target/s390x_unknown_linux_gnu.rs | 1 +
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src/librustc_trans/consts.rs | 24 ++++++++++++--
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src/test/run-make/min-global-align/Makefile | 22 +++++++++++++
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.../run-make/min-global-align/min_global_align.rs | 38 ++++++++++++++++++++++
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5 files changed, 89 insertions(+), 2 deletions(-)
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create mode 100644 src/test/run-make/min-global-align/Makefile
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create mode 100644 src/test/run-make/min-global-align/min_global_align.rs
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diff --git a/src/librustc_back/target/mod.rs b/src/librustc_back/target/mod.rs
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index 130e1b695dbd..301cf3f8c820 100644
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--- a/src/librustc_back/target/mod.rs
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+++ b/src/librustc_back/target/mod.rs
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@@ -425,6 +425,9 @@ pub struct TargetOptions {
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/// Whether or not stack probes (__rust_probestack) are enabled
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pub stack_probes: bool,
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+
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+ /// The minimum alignment for global symbols.
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+ pub min_global_align: Option<u64>,
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}
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impl Default for TargetOptions {
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@@ -486,6 +489,7 @@ impl Default for TargetOptions {
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crt_static_default: false,
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crt_static_respected: false,
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stack_probes: false,
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+ min_global_align: None,
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}
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}
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}
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@@ -724,6 +728,7 @@ impl Target {
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key!(crt_static_default, bool);
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key!(crt_static_respected, bool);
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key!(stack_probes, bool);
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+ key!(min_global_align, Option<u64>);
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if let Some(array) = obj.find("abi-blacklist").and_then(Json::as_array) {
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for name in array.iter().filter_map(|abi| abi.as_string()) {
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@@ -914,6 +919,7 @@ impl ToJson for Target {
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target_option_val!(crt_static_default);
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target_option_val!(crt_static_respected);
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target_option_val!(stack_probes);
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+ target_option_val!(min_global_align);
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if default.abi_blacklist != self.options.abi_blacklist {
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d.insert("abi-blacklist".to_string(), self.options.abi_blacklist.iter()
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diff --git a/src/librustc_back/target/s390x_unknown_linux_gnu.rs b/src/librustc_back/target/s390x_unknown_linux_gnu.rs
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index 78a6bb7933d9..aad9effacd44 100644
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--- a/src/librustc_back/target/s390x_unknown_linux_gnu.rs
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+++ b/src/librustc_back/target/s390x_unknown_linux_gnu.rs
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@@ -22,6 +22,7 @@ pub fn target() -> TargetResult {
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base.max_atomic_width = Some(64);
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// see #36994
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base.exe_allocation_crate = None;
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+ base.min_global_align = Some(16);
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Ok(Target {
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llvm_target: "s390x-unknown-linux-gnu".to_string(),
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diff --git a/src/librustc_trans/consts.rs b/src/librustc_trans/consts.rs
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index 310cd6fe9559..f7f9b9386841 100644
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--- a/src/librustc_trans/consts.rs
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+++ b/src/librustc_trans/consts.rs
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@@ -26,6 +26,7 @@ use rustc::ty;
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use rustc::hir;
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+use std::cmp;
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use std::ffi::{CStr, CString};
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use syntax::ast;
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use syntax::attr;
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@@ -42,6 +43,25 @@ pub fn bitcast(val: ValueRef, ty: Type) -> ValueRef {
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}
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}
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+fn set_global_alignment(ccx: &CrateContext,
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+ gv: ValueRef,
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+ mut align: machine::llalign) {
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+ // The target may require greater alignment for globals than the type does.
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+ // Note: GCC and Clang also allow `__attribute__((aligned))` on variables,
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+ // which can force it to be smaller. Rust doesn't support this yet.
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+ if let Some(min) = ccx.sess().target.target.options.min_global_align {
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+ match ty::layout::Align::from_bits(min, min) {
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+ Ok(min) => align = cmp::max(align, min.abi() as machine::llalign),
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+ Err(err) => {
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+ ccx.sess().err(&format!("invalid minimum global alignment: {}", err));
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+ }
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+ }
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+ }
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+ unsafe {
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+ llvm::LLVMSetAlignment(gv, align);
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+ }
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+}
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+
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pub fn addr_of_mut(ccx: &CrateContext,
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cv: ValueRef,
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align: machine::llalign,
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@@ -53,7 +73,7 @@ pub fn addr_of_mut(ccx: &CrateContext,
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bug!("symbol `{}` is already defined", name);
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});
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llvm::LLVMSetInitializer(gv, cv);
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- llvm::LLVMSetAlignment(gv, align);
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+ set_global_alignment(ccx, gv, align);
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llvm::LLVMRustSetLinkage(gv, llvm::Linkage::InternalLinkage);
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SetUnnamedAddr(gv, true);
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gv
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@@ -271,7 +291,7 @@ pub fn trans_static<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
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ccx.statics_to_rauw().borrow_mut().push((g, new_g));
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new_g
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};
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- llvm::LLVMSetAlignment(g, ccx.align_of(ty));
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+ set_global_alignment(ccx, g, ccx.align_of(ty));
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llvm::LLVMSetInitializer(g, v);
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// As an optimization, all shared statics which do not have interior
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diff --git a/src/test/run-make/min-global-align/Makefile b/src/test/run-make/min-global-align/Makefile
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new file mode 100644
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index 000000000000..2eacc36f380d
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--- /dev/null
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+++ b/src/test/run-make/min-global-align/Makefile
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@@ -0,0 +1,22 @@
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+-include ../tools.mk
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+
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+# This tests ensure that global variables respect the target minimum alignment.
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+# The three bools `STATIC_BOOL`, `STATIC_MUT_BOOL`, and `CONST_BOOL` all have
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+# type-alignment of 1, but some targets require greater global alignment.
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+
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+SRC = min_global_align.rs
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+LL = $(TMPDIR)/min_global_align.ll
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+
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+all:
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+ifeq ($(UNAME),Linux)
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+# Most targets are happy with default alignment -- take i686 for example.
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+ifeq ($(filter x86,$(LLVM_COMPONENTS)),x86)
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+ $(RUSTC) --target=i686-unknown-linux-gnu --emit=llvm-ir $(SRC)
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+ [ "$$(grep -c 'align 1' "$(LL)")" -eq "3" ]
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+endif
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+# SystemZ requires even alignment for PC-relative addressing.
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+ifeq ($(filter systemz,$(LLVM_COMPONENTS)),systemz)
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+ $(RUSTC) --target=s390x-unknown-linux-gnu --emit=llvm-ir $(SRC)
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+ [ "$$(grep -c 'align 2' "$(LL)")" -eq "3" ]
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+endif
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+endif
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diff --git a/src/test/run-make/min-global-align/min_global_align.rs b/src/test/run-make/min-global-align/min_global_align.rs
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new file mode 100644
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index 000000000000..3d4f9001a747
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--- /dev/null
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+++ b/src/test/run-make/min-global-align/min_global_align.rs
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@@ -0,0 +1,38 @@
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+// Copyright 2017 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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+
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+#![feature(no_core, lang_items)]
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+#![crate_type="rlib"]
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+#![no_core]
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+
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+pub static STATIC_BOOL: bool = true;
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+
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+pub static mut STATIC_MUT_BOOL: bool = true;
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+
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+const CONST_BOOL: bool = true;
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+pub static CONST_BOOL_REF: &'static bool = &CONST_BOOL;
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+
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+
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+#[lang = "sized"]
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+trait Sized {}
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+
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+#[lang = "copy"]
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+trait Copy {}
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+
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+#[lang = "freeze"]
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+trait Freeze {}
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+
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+#[lang = "sync"]
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+trait Sync {}
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+impl Sync for bool {}
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+impl Sync for &'static bool {}
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+
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+#[lang="drop_in_place"]
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+pub unsafe fn drop_in_place<T: ?Sized>(_: *mut T) { }
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--
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2.13.5
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