| // Copyright 2012-2015 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. |
| //! Set and unset common attributes on LLVM values. |
| |
| use std::ffi::{CStr, CString}; |
| |
| use llvm::{self, Attribute, ValueRef}; |
| use llvm::AttributePlace::Function; |
| pub use syntax::attr::InlineAttr; |
| use syntax::ast; |
| use context::CrateContext; |
| |
| /// Mark LLVM function to use provided inline heuristic. |
| #[inline] |
| pub fn inline(val: ValueRef, inline: InlineAttr) { |
| use self::InlineAttr::*; |
| match inline { |
| Hint => Attribute::InlineHint.apply_llfn(Function, val), |
| Always => Attribute::AlwaysInline.apply_llfn(Function, val), |
| Never => Attribute::NoInline.apply_llfn(Function, val), |
| None => { |
| Attribute::InlineHint.unapply_llfn(Function, val); |
| Attribute::AlwaysInline.unapply_llfn(Function, val); |
| Attribute::NoInline.unapply_llfn(Function, val); |
| }, |
| }; |
| } |
| |
| /// Tell LLVM to emit or not emit the information necessary to unwind the stack for the function. |
| #[inline] |
| pub fn emit_uwtable(val: ValueRef, emit: bool) { |
| Attribute::UWTable.toggle_llfn(Function, val, emit); |
| } |
| |
| /// Tell LLVM whether the function can or cannot unwind. |
| #[inline] |
| pub fn unwind(val: ValueRef, can_unwind: bool) { |
| Attribute::NoUnwind.toggle_llfn(Function, val, !can_unwind); |
| } |
| |
| /// Tell LLVM whether it should optimise function for size. |
| #[inline] |
| #[allow(dead_code)] // possibly useful function |
| pub fn set_optimize_for_size(val: ValueRef, optimize: bool) { |
| Attribute::OptimizeForSize.toggle_llfn(Function, val, optimize); |
| } |
| |
| /// Tell LLVM if this function should be 'naked', i.e. skip the epilogue and prologue. |
| #[inline] |
| pub fn naked(val: ValueRef, is_naked: bool) { |
| Attribute::Naked.toggle_llfn(Function, val, is_naked); |
| } |
| |
| pub fn set_frame_pointer_elimination(ccx: &CrateContext, llfn: ValueRef) { |
| // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a |
| // parameter. |
| if ccx.sess().must_not_eliminate_frame_pointers() { |
| llvm::AddFunctionAttrStringValue( |
| llfn, llvm::AttributePlace::Function, |
| cstr("no-frame-pointer-elim\0"), cstr("true\0")); |
| } |
| } |
| |
| /// Composite function which sets LLVM attributes for function depending on its AST (#[attribute]) |
| /// attributes. |
| pub fn from_fn_attrs(ccx: &CrateContext, attrs: &[ast::Attribute], llfn: ValueRef) { |
| use syntax::attr::*; |
| inline(llfn, find_inline_attr(Some(ccx.sess().diagnostic()), attrs)); |
| |
| set_frame_pointer_elimination(ccx, llfn); |
| let mut target_features = vec![]; |
| for attr in attrs { |
| if attr.check_name("target_feature") { |
| if let Some(val) = attr.value_str() { |
| for feat in val.as_str().split(",").map(|f| f.trim()) { |
| if !feat.is_empty() && !feat.contains('\0') { |
| target_features.push(feat.to_string()); |
| } |
| } |
| } |
| } else if attr.check_name("cold") { |
| Attribute::Cold.apply_llfn(Function, llfn); |
| } else if attr.check_name("naked") { |
| naked(llfn, true); |
| } else if attr.check_name("allocator") { |
| Attribute::NoAlias.apply_llfn( |
| llvm::AttributePlace::ReturnValue(), llfn); |
| } else if attr.check_name("unwind") { |
| unwind(llfn, true); |
| } |
| } |
| if !target_features.is_empty() { |
| let val = CString::new(target_features.join(",")).unwrap(); |
| llvm::AddFunctionAttrStringValue( |
| llfn, llvm::AttributePlace::Function, |
| cstr("target-features\0"), &val); |
| } |
| } |
| |
| fn cstr(s: &'static str) -> &CStr { |
| CStr::from_bytes_with_nul(s.as_bytes()).expect("null-terminated string") |
| } |