1 #![allow(non_camel_case_types, non_snake_case)]
3 //! Code that is useful in various codegen modules.
5 use crate::llvm::{self, True, False, Bool, BasicBlock, OperandBundleDef};
8 use crate::type_::Type;
9 use crate::type_of::LayoutLlvmExt;
10 use crate::value::Value;
11 use rustc_codegen_ssa::traits::*;
13 use crate::consts::const_alloc_to_llvm;
14 use rustc::ty::layout::{HasDataLayout, LayoutOf, self, TyLayout, Size};
15 use rustc::mir::interpret::{Scalar, GlobalAlloc, Allocation};
16 use rustc_codegen_ssa::mir::place::PlaceRef;
18 use libc::{c_uint, c_char};
20 use syntax::symbol::LocalInternedString;
21 use syntax::ast::Mutability;
23 pub use crate::context::CodegenCx;
26 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
28 * An "extern" is an LLVM symbol we wind up emitting an undefined external
29 * reference to. This means "we don't have the thing in this compilation unit,
30 * please make sure you link it in at runtime". This could be a reference to
31 * C code found in a C library, or rust code found in a rust crate.
33 * Most "externs" are implicitly declared (automatically) as a result of a
34 * user declaring an extern _module_ dependency; this causes the rust driver
35 * to locate an extern crate, scan its compilation metadata, and emit extern
36 * declarations for any symbols used by the declaring crate.
38 * A "foreign" is an extern that references C (or other non-rust ABI) code.
39 * There is no metadata to scan for extern references so in these cases either
40 * a header-digester like bindgen, or manual function prototypes, have to
41 * serve as declarators. So these are usually given explicitly as prototype
42 * declarations, in rust code, with ABI attributes on them noting which ABI to
45 * An "upcall" is a foreign call generated by the compiler (not corresponding
46 * to any user-written call in the code) into the runtime library, to perform
47 * some helper task such as bringing a task to life, allocating memory, etc.
51 /// A structure representing an active landing pad for the duration of a basic
54 /// Each `Block` may contain an instance of this, indicating whether the block
55 /// is part of a landing pad or not. This is used to make decision about whether
56 /// to emit `invoke` instructions (e.g., in a landing pad we don't continue to
57 /// use `invoke`) and also about various function call metadata.
59 /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
60 /// just a bunch of `None` instances (not too interesting), but for MSVC
61 /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
62 /// When inside of a landing pad, each function call in LLVM IR needs to be
63 /// annotated with which landing pad it's a part of. This is accomplished via
64 /// the `OperandBundleDef` value created for MSVC landing pads.
65 pub struct Funclet<'ll> {
66 cleanuppad: &'ll Value,
67 operand: OperandBundleDef<'ll>,
71 pub fn new(cleanuppad: &'ll Value) -> Self {
74 operand: OperandBundleDef::new("funclet", &[cleanuppad]),
78 pub fn cleanuppad(&self) -> &'ll Value {
82 pub fn bundle(&self) -> &OperandBundleDef<'ll> {
87 impl BackendTypes for CodegenCx<'ll, 'tcx> {
88 type Value = &'ll Value;
89 type BasicBlock = &'ll BasicBlock;
90 type Type = &'ll Type;
91 type Funclet = Funclet<'ll>;
93 type DIScope = &'ll llvm::debuginfo::DIScope;
96 impl CodegenCx<'ll, 'tcx> {
102 assert_eq!(abi::FAT_PTR_ADDR, 0);
103 assert_eq!(abi::FAT_PTR_EXTRA, 1);
104 self.const_struct(&[ptr, meta], false)
107 pub fn const_array(&self, ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {
109 return llvm::LLVMConstArray(ty, elts.as_ptr(), elts.len() as c_uint);
113 pub fn const_vector(&self, elts: &[&'ll Value]) -> &'ll Value {
115 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
119 pub fn const_bytes(&self, bytes: &[u8]) -> &'ll Value {
120 bytes_in_context(self.llcx, bytes)
125 s: LocalInternedString,
126 null_terminated: bool,
129 if let Some(&llval) = self.const_cstr_cache.borrow().get(&s) {
133 let sc = llvm::LLVMConstStringInContext(self.llcx,
134 s.as_ptr() as *const c_char,
136 !null_terminated as Bool);
137 let sym = self.generate_local_symbol_name("str");
138 let g = self.define_global(&sym[..], self.val_ty(sc)).unwrap_or_else(||{
139 bug!("symbol `{}` is already defined", sym);
141 llvm::LLVMSetInitializer(g, sc);
142 llvm::LLVMSetGlobalConstant(g, True);
143 llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
145 self.const_cstr_cache.borrow_mut().insert(s, g);
150 pub fn const_str_slice(&self, s: LocalInternedString) -> &'ll Value {
152 let cs = consts::ptrcast(self.const_cstr(s, false),
153 self.type_ptr_to(self.layout_of(self.tcx.mk_str()).llvm_type(self)));
154 self.const_fat_ptr(cs, self.const_usize(len as u64))
157 pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
159 assert_eq!(idx as c_uint as u64, idx);
160 let us = &[idx as c_uint];
161 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
163 debug!("const_get_elt(v={:?}, idx={}, r={:?})",
171 impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
172 fn const_null(&self, t: &'ll Type) -> &'ll Value {
174 llvm::LLVMConstNull(t)
178 fn const_undef(&self, t: &'ll Type) -> &'ll Value {
180 llvm::LLVMGetUndef(t)
184 fn const_int(&self, t: &'ll Type, i: i64) -> &'ll Value {
186 llvm::LLVMConstInt(t, i as u64, True)
190 fn const_uint(&self, t: &'ll Type, i: u64) -> &'ll Value {
192 llvm::LLVMConstInt(t, i, False)
196 fn const_uint_big(&self, t: &'ll Type, u: u128) -> &'ll Value {
198 let words = [u as u64, (u >> 64) as u64];
199 llvm::LLVMConstIntOfArbitraryPrecision(t, 2, words.as_ptr())
203 fn const_bool(&self, val: bool) -> &'ll Value {
204 self.const_uint(self.type_i1(), val as u64)
207 fn const_i32(&self, i: i32) -> &'ll Value {
208 self.const_int(self.type_i32(), i as i64)
211 fn const_u32(&self, i: u32) -> &'ll Value {
212 self.const_uint(self.type_i32(), i as u64)
215 fn const_u64(&self, i: u64) -> &'ll Value {
216 self.const_uint(self.type_i64(), i)
219 fn const_usize(&self, i: u64) -> &'ll Value {
220 let bit_size = self.data_layout().pointer_size.bits();
222 // make sure it doesn't overflow
223 assert!(i < (1<<bit_size));
226 self.const_uint(self.isize_ty, i)
229 fn const_u8(&self, i: u8) -> &'ll Value {
230 self.const_uint(self.type_i8(), i as u64)
233 fn const_real(&self, t: &'ll Type, val: f64) -> &'ll Value {
234 unsafe { llvm::LLVMConstReal(t, val) }
242 struct_in_context(self.llcx, elts, packed)
245 fn const_to_uint(&self, v: &'ll Value) -> u64 {
247 llvm::LLVMConstIntGetZExtValue(v)
251 fn is_const_integral(&self, v: &'ll Value) -> bool {
253 llvm::LLVMIsAConstantInt(v).is_some()
257 fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {
259 if self.is_const_integral(v) {
260 let (mut lo, mut hi) = (0u64, 0u64);
261 let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
264 Some(hi_lo_to_u128(lo, hi))
274 fn scalar_to_backend(
277 layout: &layout::Scalar,
280 let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
282 Scalar::Raw { size: 0, .. } => {
283 assert_eq!(0, layout.value.size(self).bytes());
284 self.const_undef(self.type_ix(0))
286 Scalar::Raw { data, size } => {
287 assert_eq!(size as u64, layout.value.size(self).bytes());
288 let llval = self.const_uint_big(self.type_ix(bitsize), data);
289 if layout.value == layout::Pointer {
290 unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
292 self.const_bitcast(llval, llty)
295 Scalar::Ptr(ptr) => {
296 let alloc_kind = self.tcx.alloc_map.lock().get(ptr.alloc_id);
297 let base_addr = match alloc_kind {
298 Some(GlobalAlloc::Memory(alloc)) => {
299 let init = const_alloc_to_llvm(self, alloc);
300 if alloc.mutability == Mutability::Mutable {
301 self.static_addr_of_mut(init, alloc.align, None)
303 self.static_addr_of(init, alloc.align, None)
306 Some(GlobalAlloc::Function(fn_instance)) => {
307 self.get_fn(fn_instance)
309 Some(GlobalAlloc::Static(def_id)) => {
310 assert!(self.tcx.is_static(def_id));
311 self.get_static(def_id)
313 None => bug!("missing allocation {:?}", ptr.alloc_id),
315 let llval = unsafe { llvm::LLVMConstInBoundsGEP(
316 self.const_bitcast(base_addr, self.type_i8p()),
317 &self.const_usize(ptr.offset.bytes()),
320 if layout.value != layout::Pointer {
321 unsafe { llvm::LLVMConstPtrToInt(llval, llty) }
323 self.const_bitcast(llval, llty)
331 layout: TyLayout<'tcx>,
334 ) -> PlaceRef<'tcx, &'ll Value> {
335 assert_eq!(alloc.align, layout.align.abi);
336 let llty = self.type_ptr_to(layout.llvm_type(self));
337 let llval = if layout.size == Size::ZERO {
338 let llval = self.const_usize(alloc.align.bytes());
339 unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
341 let init = const_alloc_to_llvm(self, alloc);
342 let base_addr = self.static_addr_of(init, alloc.align, None);
344 let llval = unsafe { llvm::LLVMConstInBoundsGEP(
345 self.const_bitcast(base_addr, self.type_i8p()),
346 &self.const_usize(offset.bytes()),
349 self.const_bitcast(llval, llty)
351 PlaceRef::new_sized(llval, layout, alloc.align)
354 fn const_ptrcast(&self, val: &'ll Value, ty: &'ll Type) -> &'ll Value {
355 consts::ptrcast(val, ty)
359 pub fn val_ty(v: &'ll Value) -> &'ll Type {
365 pub fn bytes_in_context(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value {
367 let ptr = bytes.as_ptr() as *const c_char;
368 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
372 pub fn struct_in_context(
373 llcx: &'a llvm::Context,
378 llvm::LLVMConstStructInContext(llcx,
379 elts.as_ptr(), elts.len() as c_uint,
385 fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
386 ((hi as u128) << 64) | (lo as u128)