1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![allow(non_camel_case_types, non_snake_case)]
13 //! Code that is useful in various codegen modules.
15 use llvm::{self, TypeKind};
16 use llvm::{True, False, Bool, BasicBlock};
17 use rustc::hir::def_id::DefId;
18 use rustc::middle::lang_items::LangItem;
25 use type_of::LayoutLlvmExt;
27 use interfaces::{Backend, CommonMethods};
29 use rustc::ty::{self, Ty, TyCtxt};
30 use rustc::ty::layout::{HasDataLayout, LayoutOf};
32 use interfaces::BuilderMethods;
34 use libc::{c_uint, c_char};
36 use syntax::symbol::LocalInternedString;
37 use syntax_pos::{Span, DUMMY_SP};
39 pub use context::CodegenCx;
41 pub fn type_needs_drop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
42 ty.needs_drop(tcx, ty::ParamEnv::reveal_all())
45 pub fn type_is_sized<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
46 ty.is_sized(tcx.at(DUMMY_SP), ty::ParamEnv::reveal_all())
49 pub fn type_is_freeze<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
50 ty.is_freeze(tcx, ty::ParamEnv::reveal_all(), DUMMY_SP)
53 pub struct OperandBundleDef<'a, Value : 'a> {
58 impl OperandBundleDef<'ll, &'ll Value> {
59 pub fn new(name: &'ll str, val: &'ll Value) -> Self {
67 pub enum IntPredicate {
81 pub enum RealPredicate {
100 pub enum AtomicRmwBinOp {
114 pub enum AtomicOrdering {
119 // Consume, // Not specified yet.
123 SequentiallyConsistent,
126 pub enum SynchronizationScope {
127 // FIXME: figure out if this variant is needed at all.
135 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
137 * An "extern" is an LLVM symbol we wind up emitting an undefined external
138 * reference to. This means "we don't have the thing in this compilation unit,
139 * please make sure you link it in at runtime". This could be a reference to
140 * C code found in a C library, or rust code found in a rust crate.
142 * Most "externs" are implicitly declared (automatically) as a result of a
143 * user declaring an extern _module_ dependency; this causes the rust driver
144 * to locate an extern crate, scan its compilation metadata, and emit extern
145 * declarations for any symbols used by the declaring crate.
147 * A "foreign" is an extern that references C (or other non-rust ABI) code.
148 * There is no metadata to scan for extern references so in these cases either
149 * a header-digester like bindgen, or manual function prototypes, have to
150 * serve as declarators. So these are usually given explicitly as prototype
151 * declarations, in rust code, with ABI attributes on them noting which ABI to
154 * An "upcall" is a foreign call generated by the compiler (not corresponding
155 * to any user-written call in the code) into the runtime library, to perform
156 * some helper task such as bringing a task to life, allocating memory, etc.
160 /// A structure representing an active landing pad for the duration of a basic
163 /// Each `Block` may contain an instance of this, indicating whether the block
164 /// is part of a landing pad or not. This is used to make decision about whether
165 /// to emit `invoke` instructions (e.g. in a landing pad we don't continue to
166 /// use `invoke`) and also about various function call metadata.
168 /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
169 /// just a bunch of `None` instances (not too interesting), but for MSVC
170 /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
171 /// When inside of a landing pad, each function call in LLVM IR needs to be
172 /// annotated with which landing pad it's a part of. This is accomplished via
173 /// the `OperandBundleDef` value created for MSVC landing pads.
174 pub struct Funclet<'ll> {
175 cleanuppad: &'ll Value,
176 operand: OperandBundleDef<'ll, &'ll Value>,
180 pub fn new(cleanuppad: &'ll Value) -> Self {
183 operand: OperandBundleDef::new("funclet", cleanuppad),
187 pub fn cleanuppad(&self) -> &'ll Value {
191 pub fn bundle(&self) -> &OperandBundleDef<'ll, &'ll Value> {
196 impl Backend for CodegenCx<'ll, 'tcx> {
197 type Value = &'ll Value;
198 type BasicBlock = &'ll BasicBlock;
199 type Type = &'ll Type;
200 type Context = &'ll llvm::Context;
203 impl<'ll, 'tcx : 'll> CommonMethods for CodegenCx<'ll, 'tcx> {
204 fn val_ty(v: &'ll Value) -> &'ll Type {
210 // LLVM constant constructors.
211 fn c_null(t: &'ll Type) -> &'ll Value {
213 llvm::LLVMConstNull(t)
217 fn c_undef(t: &'ll Type) -> &'ll Value {
219 llvm::LLVMGetUndef(t)
223 fn c_int(t: &'ll Type, i: i64) -> &'ll Value {
225 llvm::LLVMConstInt(t, i as u64, True)
229 fn c_uint(t: &'ll Type, i: u64) -> &'ll Value {
231 llvm::LLVMConstInt(t, i, False)
235 fn c_uint_big(t: &'ll Type, u: u128) -> &'ll Value {
237 let words = [u as u64, (u >> 64) as u64];
238 llvm::LLVMConstIntOfArbitraryPrecision(t, 2, words.as_ptr())
242 fn c_bool(&self, val: bool) -> &'ll Value {
243 Self::c_uint(Type::i1(&self), val as u64)
246 fn c_i32(&self, i: i32) -> &'ll Value {
247 Self::c_int(Type::i32(&self), i as i64)
250 fn c_u32(&self, i: u32) -> &'ll Value {
251 Self::c_uint(Type::i32(&self), i as u64)
254 fn c_u64(&self, i: u64) -> &'ll Value {
255 Self::c_uint(Type::i64(&self), i)
258 fn c_usize(&self, i: u64) -> &'ll Value {
259 let bit_size = self.data_layout().pointer_size.bits();
261 // make sure it doesn't overflow
262 assert!(i < (1<<bit_size));
265 Self::c_uint(&self.isize_ty, i)
268 fn c_u8(&self, i: u8) -> &'ll Value {
269 Self::c_uint(Type::i8(&self), i as u64)
273 // This is a 'c-like' raw string, which differs from
274 // our boxed-and-length-annotated strings.
277 s: LocalInternedString,
278 null_terminated: bool,
281 if let Some(&llval) = &self.const_cstr_cache.borrow().get(&s) {
285 let sc = llvm::LLVMConstStringInContext(&self.llcx,
286 s.as_ptr() as *const c_char,
288 !null_terminated as Bool);
289 let sym = &self.generate_local_symbol_name("str");
290 let g = declare::define_global(&self, &sym[..], Self::val_ty(sc)).unwrap_or_else(||{
291 bug!("symbol `{}` is already defined", sym);
293 llvm::LLVMSetInitializer(g, sc);
294 llvm::LLVMSetGlobalConstant(g, True);
295 llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
297 &self.const_cstr_cache.borrow_mut().insert(s, g);
302 // NB: Do not use `do_spill_noroot` to make this into a constant string, or
303 // you will be kicked off fast isel. See issue #4352 for an example of this.
304 fn c_str_slice(&self, s: LocalInternedString) -> &'ll Value {
306 let cs = consts::ptrcast(&self.c_cstr(s, false),
307 &self.layout_of(&self.tcx.mk_str()).llvm_type(&self).ptr_to());
308 &self.c_fat_ptr(cs, &self.c_usize(len as u64))
316 assert_eq!(abi::FAT_PTR_ADDR, 0);
317 assert_eq!(abi::FAT_PTR_EXTRA, 1);
318 &self.c_struct(&[ptr, meta], false)
326 Self::c_struct_in_context(&self.llcx, elts, packed)
329 fn c_struct_in_context(
330 llcx: &'a llvm::Context,
335 llvm::LLVMConstStructInContext(llcx,
336 elts.as_ptr(), elts.len() as c_uint,
341 fn c_array(ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {
343 return llvm::LLVMConstArray(ty, elts.as_ptr(), elts.len() as c_uint);
347 fn c_vector(elts: &[&'ll Value]) -> &'ll Value {
349 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
353 fn c_bytes(&self, bytes: &[u8]) -> &'ll Value {
354 Self::c_bytes_in_context(&self.llcx, bytes)
357 fn c_bytes_in_context(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value {
359 let ptr = bytes.as_ptr() as *const c_char;
360 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
364 fn const_get_elt(v: &'ll Value, idx: u64) -> &'ll Value {
366 assert_eq!(idx as c_uint as u64, idx);
367 let us = &[idx as c_uint];
368 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
370 debug!("const_get_elt(v={:?}, idx={}, r={:?})",
377 fn const_get_real(v: &'ll Value) -> Option<(f64, bool)> {
379 if Self::is_const_real(v) {
380 let mut loses_info: llvm::Bool = ::std::mem::uninitialized();
381 let r = llvm::LLVMConstRealGetDouble(v, &mut loses_info);
382 let loses_info = if loses_info == 1 { true } else { false };
383 Some((r, loses_info))
390 fn const_to_uint(v: &'ll Value) -> u64 {
392 llvm::LLVMConstIntGetZExtValue(v)
396 fn is_const_integral(v: &'ll Value) -> bool {
398 llvm::LLVMIsAConstantInt(v).is_some()
402 fn is_const_real(v: &'ll Value) -> bool {
404 llvm::LLVMIsAConstantFP(v).is_some()
408 fn const_to_opt_u128(v: &'ll Value, sign_ext: bool) -> Option<u128> {
410 if Self::is_const_integral(v) {
411 let (mut lo, mut hi) = (0u64, 0u64);
412 let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
415 Some(hi_lo_to_u128(lo, hi))
427 fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
428 ((hi as u128) << 64) | (lo as u128)
431 pub fn langcall(tcx: TyCtxt,
436 tcx.lang_items().require(li).unwrap_or_else(|s| {
437 let msg = format!("{} {}", msg, s);
439 Some(span) => tcx.sess.span_fatal(span, &msg[..]),
440 None => tcx.sess.fatal(&msg[..]),
445 // To avoid UB from LLVM, these two functions mask RHS with an
446 // appropriate mask unconditionally (i.e. the fallback behavior for
447 // all shifts). For 32- and 64-bit types, this matches the semantics
448 // of Java. (See related discussion on #1877 and #10183.)
450 pub fn build_unchecked_lshift(
451 bx: &Builder<'a, 'll, 'tcx>,
455 let rhs = base::cast_shift_expr_rhs(bx, hir::BinOpKind::Shl, lhs, rhs);
456 // #1877, #10183: Ensure that input is always valid
457 let rhs = shift_mask_rhs(bx, rhs);
461 pub fn build_unchecked_rshift(
462 bx: &Builder<'a, 'll, 'tcx>, lhs_t: Ty<'tcx>, lhs: &'ll Value, rhs: &'ll Value
464 let rhs = base::cast_shift_expr_rhs(bx, hir::BinOpKind::Shr, lhs, rhs);
465 // #1877, #10183: Ensure that input is always valid
466 let rhs = shift_mask_rhs(bx, rhs);
467 let is_signed = lhs_t.is_signed();
475 fn shift_mask_rhs(bx: &Builder<'a, 'll, 'tcx>, rhs: &'ll Value) -> &'ll Value {
476 let rhs_llty = CodegenCx::val_ty(rhs);
477 bx.and(rhs, shift_mask_val(bx, rhs_llty, rhs_llty, false))
480 pub fn shift_mask_val(
481 bx: &Builder<'a, 'll, 'tcx>,
483 mask_llty: &'ll Type,
486 let kind = llty.kind();
488 TypeKind::Integer => {
489 // i8/u8 can shift by at most 7, i16/u16 by at most 15, etc.
490 let val = llty.int_width() - 1;
492 CodegenCx::c_int(mask_llty, !val as i64)
494 CodegenCx::c_uint(mask_llty, val)
497 TypeKind::Vector => {
498 let mask = shift_mask_val(bx, llty.element_type(), mask_llty.element_type(), invert);
499 bx.vector_splat(mask_llty.vector_length(), mask)
501 _ => bug!("shift_mask_val: expected Integer or Vector, found {:?}", kind),