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 |
3 files changed, 29 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 |