diff options
| -rw-r--r-- | src/librustc_back/target/mod.rs | 6 | ||||
| -rw-r--r-- | src/librustc_back/target/s390x_unknown_linux_gnu.rs | 1 | ||||
| -rw-r--r-- | src/librustc_trans/consts.rs | 24 | ||||
| -rw-r--r-- | src/test/run-make/min-global-align/Makefile | 22 | ||||
| -rw-r--r-- | src/test/run-make/min-global-align/min_global_align.rs | 38 |
5 files changed, 89 insertions, 2 deletions
diff --git a/src/librustc_back/target/mod.rs b/src/librustc_back/target/mod.rs index 130e1b695db..301cf3f8c82 100644 --- a/src/librustc_back/target/mod.rs +++ b/src/librustc_back/target/mod.rs @@ -425,6 +425,9 @@ pub struct TargetOptions { /// Whether or not stack probes (__rust_probestack) are enabled pub stack_probes: bool, + + /// The minimum alignment for global symbols. + pub min_global_align: Option<u64>, } impl Default for TargetOptions { @@ -486,6 +489,7 @@ impl Default for TargetOptions { crt_static_default: false, crt_static_respected: false, stack_probes: false, + min_global_align: None, } } } @@ -724,6 +728,7 @@ impl Target { key!(crt_static_default, bool); key!(crt_static_respected, bool); key!(stack_probes, bool); + key!(min_global_align, Option<u64>); if let Some(array) = obj.find("abi-blacklist").and_then(Json::as_array) { for name in array.iter().filter_map(|abi| abi.as_string()) { @@ -914,6 +919,7 @@ impl ToJson for Target { target_option_val!(crt_static_default); target_option_val!(crt_static_respected); target_option_val!(stack_probes); + target_option_val!(min_global_align); if default.abi_blacklist != self.options.abi_blacklist { d.insert("abi-blacklist".to_string(), self.options.abi_blacklist.iter() diff --git a/src/librustc_back/target/s390x_unknown_linux_gnu.rs b/src/librustc_back/target/s390x_unknown_linux_gnu.rs index 78a6bb7933d..aad9effacd4 100644 --- a/src/librustc_back/target/s390x_unknown_linux_gnu.rs +++ b/src/librustc_back/target/s390x_unknown_linux_gnu.rs @@ -22,6 +22,7 @@ pub fn target() -> TargetResult { base.max_atomic_width = Some(64); // see #36994 base.exe_allocation_crate = None; + base.min_global_align = Some(16); Ok(Target { llvm_target: "s390x-unknown-linux-gnu".to_string(), diff --git a/src/librustc_trans/consts.rs b/src/librustc_trans/consts.rs index a30a15f75b3..bad8a8655d0 100644 --- a/src/librustc_trans/consts.rs +++ b/src/librustc_trans/consts.rs @@ -26,6 +26,7 @@ use rustc::ty; use rustc::hir; +use std::cmp; use std::ffi::{CStr, CString}; use syntax::ast; use syntax::attr; @@ -42,6 +43,25 @@ pub fn bitcast(val: ValueRef, ty: Type) -> ValueRef { } } +fn set_global_alignment(ccx: &CrateContext, + gv: ValueRef, + mut align: machine::llalign) { + // The target may require greater alignment for globals than the type does. + // Note: GCC and Clang also allow `__attribute__((aligned))` on variables, + // which can force it to be smaller. Rust doesn't support this yet. + if let Some(min) = ccx.sess().target.target.options.min_global_align { + match ty::layout::Align::from_bits(min, min) { + Ok(min) => align = cmp::max(align, min.abi() as machine::llalign), + Err(err) => { + ccx.sess().err(&format!("invalid minimum global alignment: {}", err)); + } + } + } + unsafe { + llvm::LLVMSetAlignment(gv, align); + } +} + pub fn addr_of_mut(ccx: &CrateContext, cv: ValueRef, align: machine::llalign, @@ -53,7 +73,7 @@ pub fn addr_of_mut(ccx: &CrateContext, bug!("symbol `{}` is already defined", name); }); llvm::LLVMSetInitializer(gv, cv); - llvm::LLVMSetAlignment(gv, align); + set_global_alignment(ccx, gv, align); llvm::LLVMRustSetLinkage(gv, llvm::Linkage::InternalLinkage); SetUnnamedAddr(gv, true); gv @@ -276,7 +296,7 @@ pub fn trans_static<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ccx.statics_to_rauw().borrow_mut().push((g, new_g)); new_g }; - llvm::LLVMSetAlignment(g, ccx.align_of(ty)); + set_global_alignment(ccx, g, ccx.align_of(ty)); llvm::LLVMSetInitializer(g, v); // As an optimization, all shared statics which do not have interior diff --git a/src/test/run-make/min-global-align/Makefile b/src/test/run-make/min-global-align/Makefile new file mode 100644 index 00000000000..2eacc36f380 --- /dev/null +++ b/src/test/run-make/min-global-align/Makefile @@ -0,0 +1,22 @@ +-include ../tools.mk + +# This tests ensure that global variables respect the target minimum alignment. +# The three bools `STATIC_BOOL`, `STATIC_MUT_BOOL`, and `CONST_BOOL` all have +# type-alignment of 1, but some targets require greater global alignment. + +SRC = min_global_align.rs +LL = $(TMPDIR)/min_global_align.ll + +all: +ifeq ($(UNAME),Linux) +# Most targets are happy with default alignment -- take i686 for example. +ifeq ($(filter x86,$(LLVM_COMPONENTS)),x86) + $(RUSTC) --target=i686-unknown-linux-gnu --emit=llvm-ir $(SRC) + [ "$$(grep -c 'align 1' "$(LL)")" -eq "3" ] +endif +# SystemZ requires even alignment for PC-relative addressing. +ifeq ($(filter systemz,$(LLVM_COMPONENTS)),systemz) + $(RUSTC) --target=s390x-unknown-linux-gnu --emit=llvm-ir $(SRC) + [ "$$(grep -c 'align 2' "$(LL)")" -eq "3" ] +endif +endif 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 new file mode 100644 index 00000000000..3d4f9001a74 --- /dev/null +++ b/src/test/run-make/min-global-align/min_global_align.rs @@ -0,0 +1,38 @@ +// Copyright 2017 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(no_core, lang_items)] +#![crate_type="rlib"] +#![no_core] + +pub static STATIC_BOOL: bool = true; + +pub static mut STATIC_MUT_BOOL: bool = true; + +const CONST_BOOL: bool = true; +pub static CONST_BOOL_REF: &'static bool = &CONST_BOOL; + + +#[lang = "sized"] +trait Sized {} + +#[lang = "copy"] +trait Copy {} + +#[lang = "freeze"] +trait Freeze {} + +#[lang = "sync"] +trait Sync {} +impl Sync for bool {} +impl Sync for &'static bool {} + +#[lang="drop_in_place"] +pub unsafe fn drop_in_place<T: ?Sized>(_: *mut T) { } |