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intrinsic.rs
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#![allow(non_upper_case_globals)]
use crate::attributes;
use crate::llvm;
use crate::llvm_util;
use crate::abi::{Abi, FnType, LlvmType, PassMode};
use crate::context::CodegenCx;
use crate::type_::Type;
use crate::type_of::LayoutLlvmExt;
use crate::builder::Builder;
use crate::value::Value;
use crate::va_arg::emit_va_arg;
use rustc_codegen_ssa::MemFlags;
use rustc_codegen_ssa::mir::place::PlaceRef;
use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
use rustc_codegen_ssa::glue;
use rustc_codegen_ssa::base::{to_immediate, wants_msvc_seh, compare_simd_types};
use rustc::ty::{self, Ty};
use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, Primitive};
use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
use rustc::hir;
use syntax::ast::{self, FloatTy};
use rustc_codegen_ssa::traits::*;
use rustc::session::Session;
use syntax_pos::Span;
use std::cmp::Ordering;
use std::{iter, i128, u128};
fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
let llvm_name = match name {
"sqrtf32" => "llvm.sqrt.f32",
"sqrtf64" => "llvm.sqrt.f64",
"powif32" => "llvm.powi.f32",
"powif64" => "llvm.powi.f64",
"sinf32" => "llvm.sin.f32",
"sinf64" => "llvm.sin.f64",
"cosf32" => "llvm.cos.f32",
"cosf64" => "llvm.cos.f64",
"powf32" => "llvm.pow.f32",
"powf64" => "llvm.pow.f64",
"expf32" => "llvm.exp.f32",
"expf64" => "llvm.exp.f64",
"exp2f32" => "llvm.exp2.f32",
"exp2f64" => "llvm.exp2.f64",
"logf32" => "llvm.log.f32",
"logf64" => "llvm.log.f64",
"log10f32" => "llvm.log10.f32",
"log10f64" => "llvm.log10.f64",
"log2f32" => "llvm.log2.f32",
"log2f64" => "llvm.log2.f64",
"fmaf32" => "llvm.fma.f32",
"fmaf64" => "llvm.fma.f64",
"fabsf32" => "llvm.fabs.f32",
"fabsf64" => "llvm.fabs.f64",
"minnumf32" => "llvm.minnum.f32",
"minnumf64" => "llvm.minnum.f64",
"maxnumf32" => "llvm.maxnum.f32",
"maxnumf64" => "llvm.maxnum.f64",
"copysignf32" => "llvm.copysign.f32",
"copysignf64" => "llvm.copysign.f64",
"floorf32" => "llvm.floor.f32",
"floorf64" => "llvm.floor.f64",
"ceilf32" => "llvm.ceil.f32",
"ceilf64" => "llvm.ceil.f64",
"truncf32" => "llvm.trunc.f32",
"truncf64" => "llvm.trunc.f64",
"rintf32" => "llvm.rint.f32",
"rintf64" => "llvm.rint.f64",
"nearbyintf32" => "llvm.nearbyint.f32",
"nearbyintf64" => "llvm.nearbyint.f64",
"roundf32" => "llvm.round.f32",
"roundf64" => "llvm.round.f64",
"assume" => "llvm.assume",
"abort" => "llvm.trap",
_ => return None
};
Some(cx.get_intrinsic(&llvm_name))
}
impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
fn codegen_intrinsic_call(
&mut self,
callee_ty: Ty<'tcx>,
fn_ty: &FnType<'tcx, Ty<'tcx>>,
args: &[OperandRef<'tcx, &'ll Value>],
llresult: &'ll Value,
span: Span,
) {
let tcx = self.tcx;
let (def_id, substs) = match callee_ty.sty {
ty::FnDef(def_id, substs) => (def_id, substs),
_ => bug!("expected fn item type, found {}", callee_ty)
};
let sig = callee_ty.fn_sig(tcx);
let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
let arg_tys = sig.inputs();
let ret_ty = sig.output();
let name = &*tcx.item_name(def_id).as_str();
let llret_ty = self.layout_of(ret_ty).llvm_type(self);
let result = PlaceRef::new_sized(llresult, fn_ty.ret.layout, fn_ty.ret.layout.align.abi);
let simple = get_simple_intrinsic(self, name);
let llval = match name {
_ if simple.is_some() => {
self.call(simple.unwrap(),
&args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
None)
}
"unreachable" => {
return;
},
"likely" => {
let expect = self.get_intrinsic(&("llvm.expect.i1"));
self.call(expect, &[args[0].immediate(), self.const_bool(true)], None)
}
"unlikely" => {
let expect = self.get_intrinsic(&("llvm.expect.i1"));
self.call(expect, &[args[0].immediate(), self.const_bool(false)], None)
}
"try" => {
try_intrinsic(self,
args[0].immediate(),
args[1].immediate(),
args[2].immediate(),
llresult);
return;
}
"breakpoint" => {
let llfn = self.get_intrinsic(&("llvm.debugtrap"));
self.call(llfn, &[], None)
}
"size_of" => {
let tp_ty = substs.type_at(0);
self.const_usize(self.size_of(tp_ty).bytes())
}
"va_start" => {
self.va_start(args[0].immediate())
}
"va_end" => {
self.va_end(args[0].immediate())
}
"va_copy" => {
let intrinsic = self.cx().get_intrinsic(&("llvm.va_copy"));
self.call(intrinsic, &[args[0].immediate(), args[1].immediate()], None)
}
"va_arg" => {
match fn_ty.ret.layout.abi {
layout::Abi::Scalar(ref scalar) => {
match scalar.value {
Primitive::Int(..) => {
if self.cx().size_of(ret_ty).bytes() < 4 {
// va_arg should not be called on a integer type
// less than 4 bytes in length. If it is, promote
// the integer to a `i32` and truncate the result
// back to the smaller type.
let promoted_result = emit_va_arg(self, args[0],
tcx.types.i32);
self.trunc(promoted_result, llret_ty)
} else {
emit_va_arg(self, args[0], ret_ty)
}
}
Primitive::Float(FloatTy::F64) |
Primitive::Pointer => {
emit_va_arg(self, args[0], ret_ty)
}
// `va_arg` should never be used with the return type f32.
Primitive::Float(FloatTy::F32) => {
bug!("the va_arg intrinsic does not work with `f32`")
}
}
}
_ => {
bug!("the va_arg intrinsic does not work with non-scalar types")
}
}
}
"size_of_val" => {
let tp_ty = substs.type_at(0);
if let OperandValue::Pair(_, meta) = args[0].val {
let (llsize, _) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
llsize
} else {
self.const_usize(self.size_of(tp_ty).bytes())
}
}
"min_align_of" => {
let tp_ty = substs.type_at(0);
self.const_usize(self.align_of(tp_ty).bytes())
}
"min_align_of_val" => {
let tp_ty = substs.type_at(0);
if let OperandValue::Pair(_, meta) = args[0].val {
let (_, llalign) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
llalign
} else {
self.const_usize(self.align_of(tp_ty).bytes())
}
}
"pref_align_of" => {
let tp_ty = substs.type_at(0);
self.const_usize(self.layout_of(tp_ty).align.pref.bytes())
}
"type_name" => {
let tp_ty = substs.type_at(0);
let ty_name = self.tcx.type_name(tp_ty);
OperandRef::from_const(self, ty_name).immediate_or_packed_pair(self)
}
"type_id" => {
self.const_u64(self.tcx.type_id_hash(substs.type_at(0)))
}
"init" => {
let ty = substs.type_at(0);
if !self.layout_of(ty).is_zst() {
// Just zero out the stack slot.
// If we store a zero constant, LLVM will drown in vreg allocation for large
// data structures, and the generated code will be awful. (A telltale sign of
// this is large quantities of `mov [byte ptr foo],0` in the generated code.)
memset_intrinsic(
self,
false,
ty,
llresult,
self.const_u8(0),
self.const_usize(1)
);
}
return;
}
// Effectively no-ops
"forget" => {
return;
}
"needs_drop" => {
let tp_ty = substs.type_at(0);
self.const_bool(self.type_needs_drop(tp_ty))
}
"offset" => {
let ptr = args[0].immediate();
let offset = args[1].immediate();
self.inbounds_gep(ptr, &[offset])
}
"arith_offset" => {
let ptr = args[0].immediate();
let offset = args[1].immediate();
self.gep(ptr, &[offset])
}
"copy_nonoverlapping" => {
copy_intrinsic(self, false, false, substs.type_at(0),
args[1].immediate(), args[0].immediate(), args[2].immediate());
return;
}
"copy" => {
copy_intrinsic(self, true, false, substs.type_at(0),
args[1].immediate(), args[0].immediate(), args[2].immediate());
return;
}
"write_bytes" => {
memset_intrinsic(self, false, substs.type_at(0),
args[0].immediate(), args[1].immediate(), args[2].immediate());
return;
}
"volatile_copy_nonoverlapping_memory" => {
copy_intrinsic(self, false, true, substs.type_at(0),
args[0].immediate(), args[1].immediate(), args[2].immediate());
return;
}
"volatile_copy_memory" => {
copy_intrinsic(self, true, true, substs.type_at(0),
args[0].immediate(), args[1].immediate(), args[2].immediate());
return;
}
"volatile_set_memory" => {
memset_intrinsic(self, true, substs.type_at(0),
args[0].immediate(), args[1].immediate(), args[2].immediate());
return;
}
"volatile_load" | "unaligned_volatile_load" => {
let tp_ty = substs.type_at(0);
let mut ptr = args[0].immediate();
if let PassMode::Cast(ty) = fn_ty.ret.mode {
ptr = self.pointercast(ptr, self.type_ptr_to(ty.llvm_type(self)));
}
let load = self.volatile_load(ptr);
let align = if name == "unaligned_volatile_load" {
1
} else {
self.align_of(tp_ty).bytes() as u32
};
unsafe {
llvm::LLVMSetAlignment(load, align);
}
to_immediate(self, load, self.layout_of(tp_ty))
},
"volatile_store" => {
let dst = args[0].deref(self.cx());
args[1].val.volatile_store(self, dst);
return;
},
"unaligned_volatile_store" => {
let dst = args[0].deref(self.cx());
args[1].val.unaligned_volatile_store(self, dst);
return;
},
"prefetch_read_data" | "prefetch_write_data" |
"prefetch_read_instruction" | "prefetch_write_instruction" => {
let expect = self.get_intrinsic(&("llvm.prefetch"));
let (rw, cache_type) = match name {
"prefetch_read_data" => (0, 1),
"prefetch_write_data" => (1, 1),
"prefetch_read_instruction" => (0, 0),
"prefetch_write_instruction" => (1, 0),
_ => bug!()
};
self.call(expect, &[
args[0].immediate(),
self.const_i32(rw),
args[1].immediate(),
self.const_i32(cache_type)
], None)
},
"ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" |
"bitreverse" | "add_with_overflow" | "sub_with_overflow" |
"mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
"unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" |
"unchecked_add" | "unchecked_sub" | "unchecked_mul" | "exact_div" |
"rotate_left" | "rotate_right" | "saturating_add" | "saturating_sub" => {
let ty = arg_tys[0];
match int_type_width_signed(ty, self) {
Some((width, signed)) =>
match name {
"ctlz" | "cttz" => {
let y = self.const_bool(false);
let llfn = self.get_intrinsic(
&format!("llvm.{}.i{}", name, width),
);
self.call(llfn, &[args[0].immediate(), y], None)
}
"ctlz_nonzero" | "cttz_nonzero" => {
let y = self.const_bool(true);
let llvm_name = &format!("llvm.{}.i{}", &name[..4], width);
let llfn = self.get_intrinsic(llvm_name);
self.call(llfn, &[args[0].immediate(), y], None)
}
"ctpop" => self.call(
self.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
&[args[0].immediate()],
None
),
"bswap" => {
if width == 8 {
args[0].immediate() // byte swap a u8/i8 is just a no-op
} else {
self.call(
self.get_intrinsic(
&format!("llvm.bswap.i{}", width),
),
&[args[0].immediate()],
None,
)
}
}
"bitreverse" => {
self.call(
self.get_intrinsic(
&format!("llvm.bitreverse.i{}", width),
),
&[args[0].immediate()],
None,
)
}
"add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
let intrinsic = format!("llvm.{}{}.with.overflow.i{}",
if signed { 's' } else { 'u' },
&name[..3], width);
let llfn = self.get_intrinsic(&intrinsic);
// Convert `i1` to a `bool`, and write it to the out parameter
let pair = self.call(llfn, &[
args[0].immediate(),
args[1].immediate()
], None);
let val = self.extract_value(pair, 0);
let overflow = self.extract_value(pair, 1);
let overflow = self.zext(overflow, self.type_bool());
let dest = result.project_field(self, 0);
self.store(val, dest.llval, dest.align);
let dest = result.project_field(self, 1);
self.store(overflow, dest.llval, dest.align);
return;
},
"overflowing_add" => self.add(args[0].immediate(), args[1].immediate()),
"overflowing_sub" => self.sub(args[0].immediate(), args[1].immediate()),
"overflowing_mul" => self.mul(args[0].immediate(), args[1].immediate()),
"exact_div" =>
if signed {
self.exactsdiv(args[0].immediate(), args[1].immediate())
} else {
self.exactudiv(args[0].immediate(), args[1].immediate())
},
"unchecked_div" =>
if signed {
self.sdiv(args[0].immediate(), args[1].immediate())
} else {
self.udiv(args[0].immediate(), args[1].immediate())
},
"unchecked_rem" =>
if signed {
self.srem(args[0].immediate(), args[1].immediate())
} else {
self.urem(args[0].immediate(), args[1].immediate())
},
"unchecked_shl" => self.shl(args[0].immediate(), args[1].immediate()),
"unchecked_shr" =>
if signed {
self.ashr(args[0].immediate(), args[1].immediate())
} else {
self.lshr(args[0].immediate(), args[1].immediate())
},
"unchecked_add" => {
if signed {
self.unchecked_sadd(args[0].immediate(), args[1].immediate())
} else {
self.unchecked_uadd(args[0].immediate(), args[1].immediate())
}
},
"unchecked_sub" => {
if signed {
self.unchecked_ssub(args[0].immediate(), args[1].immediate())
} else {
self.unchecked_usub(args[0].immediate(), args[1].immediate())
}
},
"unchecked_mul" => {
if signed {
self.unchecked_smul(args[0].immediate(), args[1].immediate())
} else {
self.unchecked_umul(args[0].immediate(), args[1].immediate())
}
},
"rotate_left" | "rotate_right" => {
let is_left = name == "rotate_left";
let val = args[0].immediate();
let raw_shift = args[1].immediate();
if llvm_util::get_major_version() >= 7 {
// rotate = funnel shift with first two args the same
let llvm_name = &format!("llvm.fsh{}.i{}",
if is_left { 'l' } else { 'r' }, width);
let llfn = self.get_intrinsic(llvm_name);
self.call(llfn, &[val, val, raw_shift], None)
} else {
// rotate_left: (X << (S % BW)) | (X >> ((BW - S) % BW))
// rotate_right: (X << ((BW - S) % BW)) | (X >> (S % BW))
let width = self.const_uint(
self.type_ix(width),
width,
);
let shift = self.urem(raw_shift, width);
let width_minus_raw_shift = self.sub(width, raw_shift);
let inv_shift = self.urem(width_minus_raw_shift, width);
let shift1 = self.shl(
val,
if is_left { shift } else { inv_shift },
);
let shift2 = self.lshr(
val,
if !is_left { shift } else { inv_shift },
);
self.or(shift1, shift2)
}
},
"saturating_add" | "saturating_sub" => {
let is_add = name == "saturating_add";
let lhs = args[0].immediate();
let rhs = args[1].immediate();
if llvm_util::get_major_version() >= 8 {
let llvm_name = &format!("llvm.{}{}.sat.i{}",
if signed { 's' } else { 'u' },
if is_add { "add" } else { "sub" },
width);
let llfn = self.get_intrinsic(llvm_name);
self.call(llfn, &[lhs, rhs], None)
} else {
let llvm_name = &format!("llvm.{}{}.with.overflow.i{}",
if signed { 's' } else { 'u' },
if is_add { "add" } else { "sub" },
width);
let llfn = self.get_intrinsic(llvm_name);
let pair = self.call(llfn, &[lhs, rhs], None);
let val = self.extract_value(pair, 0);
let overflow = self.extract_value(pair, 1);
let llty = self.type_ix(width);
let limit = if signed {
let limit_lo = self.const_uint_big(
llty, (i128::MIN >> (128 - width)) as u128);
let limit_hi = self.const_uint_big(
llty, (i128::MAX >> (128 - width)) as u128);
let neg = self.icmp(
IntPredicate::IntSLT, val, self.const_uint(llty, 0));
self.select(neg, limit_hi, limit_lo)
} else if is_add {
self.const_uint_big(llty, u128::MAX >> (128 - width))
} else {
self.const_uint(llty, 0)
};
self.select(overflow, limit, val)
}
},
_ => bug!(),
},
None => {
span_invalid_monomorphization_error(
tcx.sess, span,
&format!("invalid monomorphization of `{}` intrinsic: \
expected basic integer type, found `{}`", name, ty));
return;
}
}
},
"fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
match float_type_width(arg_tys[0]) {
Some(_width) =>
match name {
"fadd_fast" => self.fadd_fast(args[0].immediate(), args[1].immediate()),
"fsub_fast" => self.fsub_fast(args[0].immediate(), args[1].immediate()),
"fmul_fast" => self.fmul_fast(args[0].immediate(), args[1].immediate()),
"fdiv_fast" => self.fdiv_fast(args[0].immediate(), args[1].immediate()),
"frem_fast" => self.frem_fast(args[0].immediate(), args[1].immediate()),
_ => bug!(),
},
None => {
span_invalid_monomorphization_error(
tcx.sess, span,
&format!("invalid monomorphization of `{}` intrinsic: \
expected basic float type, found `{}`", name, arg_tys[0]));
return;
}
}
},
"discriminant_value" => {
args[0].deref(self.cx()).codegen_get_discr(self, ret_ty)
}
name if name.starts_with("simd_") => {
match generic_simd_intrinsic(self, name,
callee_ty,
args,
ret_ty, llret_ty,
span) {
Ok(llval) => llval,
Err(()) => return
}
}
// This requires that atomic intrinsics follow a specific naming pattern:
// "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
name if name.starts_with("atomic_") => {
use rustc_codegen_ssa::common::AtomicOrdering::*;
use rustc_codegen_ssa::common::
{SynchronizationScope, AtomicRmwBinOp};
let split: Vec<&str> = name.split('_').collect();
let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
let (order, failorder) = match split.len() {
2 => (SequentiallyConsistent, SequentiallyConsistent),
3 => match split[2] {
"unordered" => (Unordered, Unordered),
"relaxed" => (Monotonic, Monotonic),
"acq" => (Acquire, Acquire),
"rel" => (Release, Monotonic),
"acqrel" => (AcquireRelease, Acquire),
"failrelaxed" if is_cxchg =>
(SequentiallyConsistent, Monotonic),
"failacq" if is_cxchg =>
(SequentiallyConsistent, Acquire),
_ => self.sess().fatal("unknown ordering in atomic intrinsic")
},
4 => match (split[2], split[3]) {
("acq", "failrelaxed") if is_cxchg =>
(Acquire, Monotonic),
("acqrel", "failrelaxed") if is_cxchg =>
(AcquireRelease, Monotonic),
_ => self.sess().fatal("unknown ordering in atomic intrinsic")
},
_ => self.sess().fatal("Atomic intrinsic not in correct format"),
};
let invalid_monomorphization = |ty| {
span_invalid_monomorphization_error(tcx.sess, span,
&format!("invalid monomorphization of `{}` intrinsic: \
expected basic integer type, found `{}`", name, ty));
};
match split[1] {
"cxchg" | "cxchgweak" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, self).is_some() {
let weak = split[1] == "cxchgweak";
let pair = self.atomic_cmpxchg(
args[0].immediate(),
args[1].immediate(),
args[2].immediate(),
order,
failorder,
weak);
let val = self.extract_value(pair, 0);
let success = self.extract_value(pair, 1);
let success = self.zext(success, self.type_bool());
let dest = result.project_field(self, 0);
self.store(val, dest.llval, dest.align);
let dest = result.project_field(self, 1);
self.store(success, dest.llval, dest.align);
return;
} else {
return invalid_monomorphization(ty);
}
}
"load" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, self).is_some() {
let size = self.size_of(ty);
self.atomic_load(args[0].immediate(), order, size)
} else {
return invalid_monomorphization(ty);
}
}
"store" => {
let ty = substs.type_at(0);
if int_type_width_signed(ty, self).is_some() {
let size = self.size_of(ty);
self.atomic_store(
args[1].immediate(),
args[0].immediate(),
order,
size
);
return;
} else {
return invalid_monomorphization(ty);
}
}
"fence" => {
self.atomic_fence(order, SynchronizationScope::CrossThread);
return;
}
"singlethreadfence" => {
self.atomic_fence(order, SynchronizationScope::SingleThread);
return;
}
// These are all AtomicRMW ops
op => {
let atom_op = match op {
"xchg" => AtomicRmwBinOp::AtomicXchg,
"xadd" => AtomicRmwBinOp::AtomicAdd,
"xsub" => AtomicRmwBinOp::AtomicSub,
"and" => AtomicRmwBinOp::AtomicAnd,
"nand" => AtomicRmwBinOp::AtomicNand,
"or" => AtomicRmwBinOp::AtomicOr,
"xor" => AtomicRmwBinOp::AtomicXor,
"max" => AtomicRmwBinOp::AtomicMax,
"min" => AtomicRmwBinOp::AtomicMin,
"umax" => AtomicRmwBinOp::AtomicUMax,
"umin" => AtomicRmwBinOp::AtomicUMin,
_ => self.sess().fatal("unknown atomic operation")
};
let ty = substs.type_at(0);
if int_type_width_signed(ty, self).is_some() {
self.atomic_rmw(
atom_op,
args[0].immediate(),
args[1].immediate(),
order
)
} else {
return invalid_monomorphization(ty);
}
}
}
}
"nontemporal_store" => {
let dst = args[0].deref(self.cx());
args[1].val.nontemporal_store(self, dst);
return;
}
_ => bug!("unknown intrinsic '{}'", name),
};
if !fn_ty.ret.is_ignore() {
if let PassMode::Cast(ty) = fn_ty.ret.mode {
let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
let ptr = self.pointercast(result.llval, ptr_llty);
self.store(llval, ptr, result.align);
} else {
OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
.val.store(self, result);
}
}
}
fn abort(&mut self) {
let fnname = self.get_intrinsic(&("llvm.trap"));
self.call(fnname, &[], None);
}
fn assume(&mut self, val: Self::Value) {
let assume_intrinsic = self.get_intrinsic("llvm.assume");
self.call(assume_intrinsic, &[val], None);
}
fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
let expect = self.get_intrinsic(&"llvm.expect.i1");
self.call(expect, &[cond, self.const_bool(expected)], None)
}
fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
let intrinsic = self.cx().get_intrinsic("llvm.va_start");
self.call(intrinsic, &[va_list], None)
}
fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
let intrinsic = self.cx().get_intrinsic("llvm.va_end");
self.call(intrinsic, &[va_list], None)
}
}
fn copy_intrinsic(
bx: &mut Builder<'a, 'll, 'tcx>,
allow_overlap: bool,
volatile: bool,
ty: Ty<'tcx>,
dst: &'ll Value,
src: &'ll Value,
count: &'ll Value,
) {
let (size, align) = bx.size_and_align_of(ty);
let size = bx.mul(bx.const_usize(size.bytes()), count);
let flags = if volatile {
MemFlags::VOLATILE
} else {
MemFlags::empty()
};
if allow_overlap {
bx.memmove(dst, align, src, align, size, flags);
} else {
bx.memcpy(dst, align, src, align, size, flags);
}
}
fn memset_intrinsic(
bx: &mut Builder<'a, 'll, 'tcx>,
volatile: bool,
ty: Ty<'tcx>,
dst: &'ll Value,
val: &'ll Value,
count: &'ll Value
) {
let (size, align) = bx.size_and_align_of(ty);
let size = bx.mul(bx.const_usize(size.bytes()), count);
let flags = if volatile {
MemFlags::VOLATILE
} else {
MemFlags::empty()
};
bx.memset(dst, val, size, align, flags);
}
fn try_intrinsic(
bx: &mut Builder<'a, 'll, 'tcx>,
func: &'ll Value,
data: &'ll Value,
local_ptr: &'ll Value,
dest: &'ll Value,
) {
if bx.sess().no_landing_pads() {
bx.call(func, &[data], None);
let ptr_align = bx.tcx().data_layout.pointer_align.abi;
bx.store(bx.const_null(bx.type_i8p()), dest, ptr_align);
} else if wants_msvc_seh(bx.sess()) {
codegen_msvc_try(bx, func, data, local_ptr, dest);
} else {
codegen_gnu_try(bx, func, data, local_ptr, dest);
}
}
// MSVC's definition of the `rust_try` function.
//
// This implementation uses the new exception handling instructions in LLVM
// which have support in LLVM for SEH on MSVC targets. Although these
// instructions are meant to work for all targets, as of the time of this
// writing, however, LLVM does not recommend the usage of these new instructions
// as the old ones are still more optimized.
fn codegen_msvc_try(
bx: &mut Builder<'a, 'll, 'tcx>,
func: &'ll Value,
data: &'ll Value,
local_ptr: &'ll Value,
dest: &'ll Value,
) {
let llfn = get_rust_try_fn(bx, &mut |mut bx| {
bx.set_personality_fn(bx.eh_personality());
let mut normal = bx.build_sibling_block("normal");
let mut catchswitch = bx.build_sibling_block("catchswitch");
let mut catchpad = bx.build_sibling_block("catchpad");
let mut caught = bx.build_sibling_block("caught");
let func = llvm::get_param(bx.llfn(), 0);
let data = llvm::get_param(bx.llfn(), 1);
let local_ptr = llvm::get_param(bx.llfn(), 2);
// We're generating an IR snippet that looks like:
//
// declare i32 @rust_try(%func, %data, %ptr) {
// %slot = alloca i64*
// invoke %func(%data) to label %normal unwind label %catchswitch
//
// normal:
// ret i32 0
//
// catchswitch:
// %cs = catchswitch within none [%catchpad] unwind to caller
//
// catchpad:
// %tok = catchpad within %cs [%type_descriptor, 0, %slot]
// %ptr[0] = %slot[0]
// %ptr[1] = %slot[1]
// catchret from %tok to label %caught
//
// caught:
// ret i32 1
// }
//
// This structure follows the basic usage of throw/try/catch in LLVM.
// For example, compile this C++ snippet to see what LLVM generates:
//
// #include <stdint.h>
//
// int bar(void (*foo)(void), uint64_t *ret) {
// try {
// foo();
// return 0;
// } catch(uint64_t a[2]) {
// ret[0] = a[0];
// ret[1] = a[1];
// return 1;
// }
// }
//
// More information can be found in libstd's seh.rs implementation.
let i64p = bx.type_ptr_to(bx.type_i64());
let ptr_align = bx.tcx().data_layout.pointer_align.abi;
let slot = bx.alloca(i64p, "slot", ptr_align);
bx.invoke(func, &[data], normal.llbb(), catchswitch.llbb(), None);
normal.ret(bx.const_i32(0));
let cs = catchswitch.catch_switch(None, None, 1);
catchswitch.add_handler(cs, catchpad.llbb());
let tydesc = match bx.tcx().lang_items().msvc_try_filter() {
Some(did) => bx.get_static(did),
None => bug!("msvc_try_filter not defined"),
};
let funclet = catchpad.catch_pad(cs, &[tydesc, bx.const_i32(0), slot]);
let addr = catchpad.load(slot, ptr_align);
let i64_align = bx.tcx().data_layout.i64_align.abi;
let arg1 = catchpad.load(addr, i64_align);
let val1 = bx.const_i32(1);
let gep1 = catchpad.inbounds_gep(addr, &[val1]);
let arg2 = catchpad.load(gep1, i64_align);
let local_ptr = catchpad.bitcast(local_ptr, i64p);
let gep2 = catchpad.inbounds_gep(local_ptr, &[val1]);
catchpad.store(arg1, local_ptr, i64_align);
catchpad.store(arg2, gep2, i64_align);
catchpad.catch_ret(&funclet, caught.llbb());
caught.ret(bx.const_i32(1));
});
// Note that no invoke is used here because by definition this function
// can't panic (that's what it's catching).
let ret = bx.call(llfn, &[func, data, local_ptr], None);
let i32_align = bx.tcx().data_layout.i32_align.abi;
bx.store(ret, dest, i32_align);
}
// Definition of the standard `try` function for Rust using the GNU-like model
// of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
// instructions).
//
// This codegen is a little surprising because we always call a shim
// function instead of inlining the call to `invoke` manually here. This is done
// because in LLVM we're only allowed to have one personality per function
// definition. The call to the `try` intrinsic is being inlined into the
// function calling it, and that function may already have other personality
// functions in play. By calling a shim we're guaranteed that our shim will have
// the right personality function.
fn codegen_gnu_try(
bx: &mut Builder<'a, 'll, 'tcx>,
func: &'ll Value,
data: &'ll Value,
local_ptr: &'ll Value,
dest: &'ll Value,
) {
let llfn = get_rust_try_fn(bx, &mut |mut bx| {
// Codegens the shims described above:
//
// bx:
// invoke %func(%args...) normal %normal unwind %catch
//
// normal:
// ret 0
//
// catch:
// (ptr, _) = landingpad
// store ptr, %local_ptr
// ret 1
//
// Note that the `local_ptr` data passed into the `try` intrinsic is
// expected to be `*mut *mut u8` for this to actually work, but that's
// managed by the standard library.
let mut then = bx.build_sibling_block("then");
let mut catch = bx.build_sibling_block("catch");
let func = llvm::get_param(bx.llfn(), 0);
let data = llvm::get_param(bx.llfn(), 1);
let local_ptr = llvm::get_param(bx.llfn(), 2);
bx.invoke(func, &[data], then.llbb(), catch.llbb(), None);
then.ret(bx.const_i32(0));
// Type indicator for the exception being thrown.
//
// The first value in this tuple is a pointer to the exception object
// being thrown. The second value is a "selector" indicating which of
// the landing pad clauses the exception's type had been matched to.
// rust_try ignores the selector.
let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
catch.add_clause(vals, bx.const_null(bx.type_i8p()));
let ptr = catch.extract_value(vals, 0);
let ptr_align = bx.tcx().data_layout.pointer_align.abi;
let bitcast = catch.bitcast(local_ptr, bx.type_ptr_to(bx.type_i8p()));
catch.store(ptr, bitcast, ptr_align);
catch.ret(bx.const_i32(1));
});
// Note that no invoke is used here because by definition this function
// can't panic (that's what it's catching).
let ret = bx.call(llfn, &[func, data, local_ptr], None);
let i32_align = bx.tcx().data_layout.i32_align.abi;
bx.store(ret, dest, i32_align);
}
// Helper function to give a Block to a closure to codegen a shim function.
// This is currently primarily used for the `try` intrinsic functions above.
fn gen_fn<'ll, 'tcx>(
cx: &CodegenCx<'ll, 'tcx>,
name: &str,
inputs: Vec<Ty<'tcx>>,
output: Ty<'tcx>,
codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
) -> &'ll Value {
let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
inputs.into_iter(),
output,
false,
hir::Unsafety::Unsafe,
Abi::Rust
));
let llfn = cx.define_internal_fn(name, rust_fn_sig);
attributes::from_fn_attrs(cx, llfn, None, rust_fn_sig);
let bx = Builder::new_block(cx, llfn, "entry-block");
codegen(bx);
llfn