// Copyright 2012-2014 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![allow(non_upper_case_globals)] use intrinsics::{self, Intrinsic}; use libc; use llvm; use llvm::{ValueRef}; use abi::{Abi, FnType}; use adt; use mir::lvalue::{LvalueRef, Alignment}; use base::*; use common::*; use declare; use glue; use type_of; use machine; use type_::Type; use rustc::ty::{self, Ty}; use rustc::hir; use syntax::ast; use syntax::symbol::Symbol; use builder::Builder; use rustc::session::Session; use syntax_pos::Span; use std::cmp::Ordering; use std::iter; fn get_simple_intrinsic(ccx: &CrateContext, name: &str) -> Option { 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", "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(ccx.get_intrinsic(&llvm_name)) } /// Remember to add all intrinsics here, in librustc_typeck/check/mod.rs, /// and in libcore/intrinsics.rs; if you need access to any llvm intrinsics, /// add them to librustc_trans/trans/context.rs pub fn trans_intrinsic_call<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, callee_ty: Ty<'tcx>, fn_ty: &FnType, llargs: &[ValueRef], llresult: ValueRef, span: Span) { let ccx = bcx.ccx; let tcx = ccx.tcx(); let (def_id, substs) = match callee_ty.sty { ty::TyFnDef(def_id, substs) => (def_id, substs), _ => bug!("expected fn item type, found {}", callee_ty) }; let sig = callee_ty.fn_sig(tcx); let sig = tcx.erase_late_bound_regions_and_normalize(&sig); let arg_tys = sig.inputs(); let ret_ty = sig.output(); let name = &*tcx.item_name(def_id).as_str(); let llret_ty = type_of::type_of(ccx, ret_ty); let simple = get_simple_intrinsic(ccx, name); let llval = match name { _ if simple.is_some() => { bcx.call(simple.unwrap(), &llargs, None) } "unreachable" => { return; }, "likely" => { let expect = ccx.get_intrinsic(&("llvm.expect.i1")); bcx.call(expect, &[llargs[0], C_bool(ccx, true)], None) } "unlikely" => { let expect = ccx.get_intrinsic(&("llvm.expect.i1")); bcx.call(expect, &[llargs[0], C_bool(ccx, false)], None) } "try" => { try_intrinsic(bcx, ccx, llargs[0], llargs[1], llargs[2], llresult); C_nil(ccx) } "breakpoint" => { let llfn = ccx.get_intrinsic(&("llvm.debugtrap")); bcx.call(llfn, &[], None) } "size_of" => { let tp_ty = substs.type_at(0); let lltp_ty = type_of::type_of(ccx, tp_ty); C_uint(ccx, machine::llsize_of_alloc(ccx, lltp_ty)) } "size_of_val" => { let tp_ty = substs.type_at(0); if !bcx.ccx.shared().type_is_sized(tp_ty) { let (llsize, _) = glue::size_and_align_of_dst(bcx, tp_ty, llargs[1]); llsize } else { let lltp_ty = type_of::type_of(ccx, tp_ty); C_uint(ccx, machine::llsize_of_alloc(ccx, lltp_ty)) } } "min_align_of" => { let tp_ty = substs.type_at(0); C_uint(ccx, ccx.align_of(tp_ty)) } "min_align_of_val" => { let tp_ty = substs.type_at(0); if !bcx.ccx.shared().type_is_sized(tp_ty) { let (_, llalign) = glue::size_and_align_of_dst(bcx, tp_ty, llargs[1]); llalign } else { C_uint(ccx, ccx.align_of(tp_ty)) } } "pref_align_of" => { let tp_ty = substs.type_at(0); let lltp_ty = type_of::type_of(ccx, tp_ty); C_uint(ccx, machine::llalign_of_pref(ccx, lltp_ty)) } "type_name" => { let tp_ty = substs.type_at(0); let ty_name = Symbol::intern(&tp_ty.to_string()).as_str(); C_str_slice(ccx, ty_name) } "type_id" => { C_u64(ccx, ccx.tcx().type_id_hash(substs.type_at(0))) } "init" => { let ty = substs.type_at(0); if !type_is_zero_size(ccx, ty) { // 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(bcx, false, ty, llresult, C_u8(ccx, 0), C_uint(ccx, 1usize)); } C_nil(ccx) } // Effectively no-ops "uninit" => { C_nil(ccx) } "needs_drop" => { let tp_ty = substs.type_at(0); C_bool(ccx, bcx.ccx.shared().type_needs_drop(tp_ty)) } "offset" => { let ptr = llargs[0]; let offset = llargs[1]; bcx.inbounds_gep(ptr, &[offset]) } "arith_offset" => { let ptr = llargs[0]; let offset = llargs[1]; bcx.gep(ptr, &[offset]) } "copy_nonoverlapping" => { copy_intrinsic(bcx, false, false, substs.type_at(0), llargs[1], llargs[0], llargs[2]) } "copy" => { copy_intrinsic(bcx, true, false, substs.type_at(0), llargs[1], llargs[0], llargs[2]) } "write_bytes" => { memset_intrinsic(bcx, false, substs.type_at(0), llargs[0], llargs[1], llargs[2]) } "volatile_copy_nonoverlapping_memory" => { copy_intrinsic(bcx, false, true, substs.type_at(0), llargs[0], llargs[1], llargs[2]) } "volatile_copy_memory" => { copy_intrinsic(bcx, true, true, substs.type_at(0), llargs[0], llargs[1], llargs[2]) } "volatile_set_memory" => { memset_intrinsic(bcx, true, substs.type_at(0), llargs[0], llargs[1], llargs[2]) } "volatile_load" => { let tp_ty = substs.type_at(0); let mut ptr = llargs[0]; if let Some(ty) = fn_ty.ret.cast { ptr = bcx.pointercast(ptr, ty.ptr_to()); } let load = bcx.volatile_load(ptr); unsafe { llvm::LLVMSetAlignment(load, ccx.align_of(tp_ty)); } to_immediate(bcx, load, tp_ty) }, "volatile_store" => { let tp_ty = substs.type_at(0); if type_is_fat_ptr(bcx.ccx, tp_ty) { bcx.volatile_store(llargs[1], get_dataptr(bcx, llargs[0])); bcx.volatile_store(llargs[2], get_meta(bcx, llargs[0])); } else { let val = if fn_ty.args[1].is_indirect() { bcx.load(llargs[1], None) } else { from_immediate(bcx, llargs[1]) }; let ptr = bcx.pointercast(llargs[0], val_ty(val).ptr_to()); let store = bcx.volatile_store(val, ptr); unsafe { llvm::LLVMSetAlignment(store, ccx.align_of(tp_ty)); } } C_nil(ccx) }, "prefetch_read_data" | "prefetch_write_data" | "prefetch_read_instruction" | "prefetch_write_instruction" => { let expect = ccx.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!() }; bcx.call(expect, &[llargs[0], C_i32(ccx, rw), llargs[1], C_i32(ccx, cache_type)], None) }, "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" | "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" | "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" => { let sty = &arg_tys[0].sty; match int_type_width_signed(sty, ccx) { Some((width, signed)) => match name { "ctlz" | "cttz" => { let y = C_bool(bcx.ccx, false); let llfn = ccx.get_intrinsic(&format!("llvm.{}.i{}", name, width)); bcx.call(llfn, &[llargs[0], y], None) } "ctlz_nonzero" | "cttz_nonzero" => { let y = C_bool(bcx.ccx, true); let llvm_name = &format!("llvm.{}.i{}", &name[..4], width); let llfn = ccx.get_intrinsic(llvm_name); bcx.call(llfn, &[llargs[0], y], None) } "ctpop" => bcx.call(ccx.get_intrinsic(&format!("llvm.ctpop.i{}", width)), &llargs, None), "bswap" => { if width == 8 { llargs[0] // byte swap a u8/i8 is just a no-op } else { bcx.call(ccx.get_intrinsic(&format!("llvm.bswap.i{}", width)), &llargs, 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 = bcx.ccx.get_intrinsic(&intrinsic); // Convert `i1` to a `bool`, and write it to the out parameter let val = bcx.call(llfn, &[llargs[0], llargs[1]], None); let result = bcx.extract_value(val, 0); let overflow = bcx.zext(bcx.extract_value(val, 1), Type::bool(ccx)); bcx.store(result, bcx.struct_gep(llresult, 0), None); bcx.store(overflow, bcx.struct_gep(llresult, 1), None); C_nil(bcx.ccx) }, "overflowing_add" => bcx.add(llargs[0], llargs[1]), "overflowing_sub" => bcx.sub(llargs[0], llargs[1]), "overflowing_mul" => bcx.mul(llargs[0], llargs[1]), "unchecked_div" => if signed { bcx.sdiv(llargs[0], llargs[1]) } else { bcx.udiv(llargs[0], llargs[1]) }, "unchecked_rem" => if signed { bcx.srem(llargs[0], llargs[1]) } else { bcx.urem(llargs[0], llargs[1]) }, "unchecked_shl" => bcx.shl(llargs[0], llargs[1]), "unchecked_shr" => if signed { bcx.ashr(llargs[0], llargs[1]) } else { bcx.lshr(llargs[0], llargs[1]) }, _ => bug!(), }, None => { span_invalid_monomorphization_error( tcx.sess, span, &format!("invalid monomorphization of `{}` intrinsic: \ expected basic integer type, found `{}`", name, sty)); C_nil(ccx) } } }, "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => { let sty = &arg_tys[0].sty; match float_type_width(sty) { Some(_width) => match name { "fadd_fast" => bcx.fadd_fast(llargs[0], llargs[1]), "fsub_fast" => bcx.fsub_fast(llargs[0], llargs[1]), "fmul_fast" => bcx.fmul_fast(llargs[0], llargs[1]), "fdiv_fast" => bcx.fdiv_fast(llargs[0], llargs[1]), "frem_fast" => bcx.frem_fast(llargs[0], llargs[1]), _ => bug!(), }, None => { span_invalid_monomorphization_error( tcx.sess, span, &format!("invalid monomorphization of `{}` intrinsic: \ expected basic float type, found `{}`", name, sty)); C_nil(ccx) } } }, "discriminant_value" => { let val_ty = substs.type_at(0); match val_ty.sty { ty::TyAdt(adt, ..) if adt.is_enum() => { adt::trans_get_discr(bcx, val_ty, llargs[0], Alignment::AbiAligned, Some(llret_ty), true) } _ => C_null(llret_ty) } } name if name.starts_with("simd_") => { generic_simd_intrinsic(bcx, name, callee_ty, &llargs, ret_ty, llret_ty, span) } // This requires that atomic intrinsics follow a specific naming pattern: // "atomic_[_]", and no ordering means SeqCst name if name.starts_with("atomic_") => { use llvm::AtomicOrdering::*; 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), _ => ccx.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), _ => ccx.sess().fatal("unknown ordering in atomic intrinsic") }, _ => ccx.sess().fatal("Atomic intrinsic not in correct format"), }; let invalid_monomorphization = |sty| { span_invalid_monomorphization_error(tcx.sess, span, &format!("invalid monomorphization of `{}` intrinsic: \ expected basic integer type, found `{}`", name, sty)); }; match split[1] { "cxchg" | "cxchgweak" => { let sty = &substs.type_at(0).sty; if int_type_width_signed(sty, ccx).is_some() { let weak = if split[1] == "cxchgweak" { llvm::True } else { llvm::False }; let val = bcx.atomic_cmpxchg(llargs[0], llargs[1], llargs[2], order, failorder, weak); let result = bcx.extract_value(val, 0); let success = bcx.zext(bcx.extract_value(val, 1), Type::bool(bcx.ccx)); bcx.store(result, bcx.struct_gep(llresult, 0), None); bcx.store(success, bcx.struct_gep(llresult, 1), None); } else { invalid_monomorphization(sty); } C_nil(ccx) } "load" => { let sty = &substs.type_at(0).sty; if int_type_width_signed(sty, ccx).is_some() { bcx.atomic_load(llargs[0], order) } else { invalid_monomorphization(sty); C_nil(ccx) } } "store" => { let sty = &substs.type_at(0).sty; if int_type_width_signed(sty, ccx).is_some() { bcx.atomic_store(llargs[1], llargs[0], order); } else { invalid_monomorphization(sty); } C_nil(ccx) } "fence" => { bcx.atomic_fence(order, llvm::SynchronizationScope::CrossThread); C_nil(ccx) } "singlethreadfence" => { bcx.atomic_fence(order, llvm::SynchronizationScope::SingleThread); C_nil(ccx) } // These are all AtomicRMW ops op => { let atom_op = match op { "xchg" => llvm::AtomicXchg, "xadd" => llvm::AtomicAdd, "xsub" => llvm::AtomicSub, "and" => llvm::AtomicAnd, "nand" => llvm::AtomicNand, "or" => llvm::AtomicOr, "xor" => llvm::AtomicXor, "max" => llvm::AtomicMax, "min" => llvm::AtomicMin, "umax" => llvm::AtomicUMax, "umin" => llvm::AtomicUMin, _ => ccx.sess().fatal("unknown atomic operation") }; let sty = &substs.type_at(0).sty; if int_type_width_signed(sty, ccx).is_some() { bcx.atomic_rmw(atom_op, llargs[0], llargs[1], order) } else { invalid_monomorphization(sty); C_nil(ccx) } } } } _ => { let intr = match Intrinsic::find(&name) { Some(intr) => intr, None => bug!("unknown intrinsic '{}'", name), }; fn one(x: Vec) -> T { assert_eq!(x.len(), 1); x.into_iter().next().unwrap() } fn ty_to_type(ccx: &CrateContext, t: &intrinsics::Type, any_changes_needed: &mut bool) -> Vec { use intrinsics::Type::*; match *t { Void => vec![Type::void(ccx)], Integer(_signed, width, llvm_width) => { *any_changes_needed |= width != llvm_width; vec![Type::ix(ccx, llvm_width as u64)] } Float(x) => { match x { 32 => vec![Type::f32(ccx)], 64 => vec![Type::f64(ccx)], _ => bug!() } } Pointer(ref t, ref llvm_elem, _const) => { *any_changes_needed |= llvm_elem.is_some(); let t = llvm_elem.as_ref().unwrap_or(t); let elem = one(ty_to_type(ccx, t, any_changes_needed)); vec![elem.ptr_to()] } Vector(ref t, ref llvm_elem, length) => { *any_changes_needed |= llvm_elem.is_some(); let t = llvm_elem.as_ref().unwrap_or(t); let elem = one(ty_to_type(ccx, t, any_changes_needed)); vec![Type::vector(&elem, length as u64)] } Aggregate(false, ref contents) => { let elems = contents.iter() .map(|t| one(ty_to_type(ccx, t, any_changes_needed))) .collect::>(); vec![Type::struct_(ccx, &elems, false)] } Aggregate(true, ref contents) => { *any_changes_needed = true; contents.iter() .flat_map(|t| ty_to_type(ccx, t, any_changes_needed)) .collect() } } } // This allows an argument list like `foo, (bar, baz), // qux` to be converted into `foo, bar, baz, qux`, integer // arguments to be truncated as needed and pointers to be // cast. fn modify_as_needed<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, t: &intrinsics::Type, arg_type: Ty<'tcx>, llarg: ValueRef) -> Vec { match *t { intrinsics::Type::Aggregate(true, ref contents) => { // We found a tuple that needs squishing! So // run over the tuple and load each field. // // This assumes the type is "simple", i.e. no // destructors, and the contents are SIMD // etc. assert!(!bcx.ccx.shared().type_needs_drop(arg_type)); let arg = LvalueRef::new_sized_ty(llarg, arg_type, Alignment::AbiAligned); (0..contents.len()).map(|i| { let (ptr, align) = arg.trans_field_ptr(bcx, i); bcx.load(ptr, align.to_align()) }).collect() } intrinsics::Type::Pointer(_, Some(ref llvm_elem), _) => { let llvm_elem = one(ty_to_type(bcx.ccx, llvm_elem, &mut false)); vec![bcx.pointercast(llarg, llvm_elem.ptr_to())] } intrinsics::Type::Vector(_, Some(ref llvm_elem), length) => { let llvm_elem = one(ty_to_type(bcx.ccx, llvm_elem, &mut false)); vec![bcx.bitcast(llarg, Type::vector(&llvm_elem, length as u64))] } intrinsics::Type::Integer(_, width, llvm_width) if width != llvm_width => { // the LLVM intrinsic uses a smaller integer // size than the C intrinsic's signature, so // we have to trim it down here. vec![bcx.trunc(llarg, Type::ix(bcx.ccx, llvm_width as u64))] } _ => vec![llarg], } } let mut any_changes_needed = false; let inputs = intr.inputs.iter() .flat_map(|t| ty_to_type(ccx, t, &mut any_changes_needed)) .collect::>(); let mut out_changes = false; let outputs = one(ty_to_type(ccx, &intr.output, &mut out_changes)); // outputting a flattened aggregate is nonsense assert!(!out_changes); let llargs = if !any_changes_needed { // no aggregates to flatten, so no change needed llargs.to_vec() } else { // there are some aggregates that need to be flattened // in the LLVM call, so we need to run over the types // again to find them and extract the arguments intr.inputs.iter() .zip(llargs) .zip(arg_tys) .flat_map(|((t, llarg), ty)| modify_as_needed(bcx, t, ty, *llarg)) .collect() }; assert_eq!(inputs.len(), llargs.len()); let val = match intr.definition { intrinsics::IntrinsicDef::Named(name) => { let f = declare::declare_cfn(ccx, name, Type::func(&inputs, &outputs)); bcx.call(f, &llargs, None) } }; match *intr.output { intrinsics::Type::Aggregate(flatten, ref elems) => { // the output is a tuple so we need to munge it properly assert!(!flatten); for i in 0..elems.len() { let val = bcx.extract_value(val, i); let lval = LvalueRef::new_sized_ty(llresult, ret_ty, Alignment::AbiAligned); let (dest, align) = lval.trans_field_ptr(bcx, i); bcx.store(val, dest, align.to_align()); } C_nil(ccx) } _ => val, } } }; if val_ty(llval) != Type::void(ccx) && machine::llsize_of_alloc(ccx, val_ty(llval)) != 0 { if let Some(ty) = fn_ty.ret.cast { let ptr = bcx.pointercast(llresult, ty.ptr_to()); bcx.store(llval, ptr, Some(ccx.align_of(ret_ty))); } else { store_ty(bcx, llval, llresult, Alignment::AbiAligned, ret_ty); } } } fn copy_intrinsic<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, allow_overlap: bool, volatile: bool, tp_ty: Ty<'tcx>, dst: ValueRef, src: ValueRef, count: ValueRef) -> ValueRef { let ccx = bcx.ccx; let lltp_ty = type_of::type_of(ccx, tp_ty); let align = C_i32(ccx, ccx.align_of(tp_ty) as i32); let size = machine::llsize_of(ccx, lltp_ty); let int_size = machine::llbitsize_of_real(ccx, ccx.int_type()); let operation = if allow_overlap { "memmove" } else { "memcpy" }; let name = format!("llvm.{}.p0i8.p0i8.i{}", operation, int_size); let dst_ptr = bcx.pointercast(dst, Type::i8p(ccx)); let src_ptr = bcx.pointercast(src, Type::i8p(ccx)); let llfn = ccx.get_intrinsic(&name); bcx.call(llfn, &[dst_ptr, src_ptr, bcx.mul(size, count), align, C_bool(ccx, volatile)], None) } fn memset_intrinsic<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, volatile: bool, ty: Ty<'tcx>, dst: ValueRef, val: ValueRef, count: ValueRef ) -> ValueRef { let ccx = bcx.ccx; let align = C_i32(ccx, ccx.align_of(ty) as i32); let lltp_ty = type_of::type_of(ccx, ty); let size = machine::llsize_of(ccx, lltp_ty); let dst = bcx.pointercast(dst, Type::i8p(ccx)); call_memset(bcx, dst, val, bcx.mul(size, count), align, volatile) } fn try_intrinsic<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, ccx: &CrateContext, func: ValueRef, data: ValueRef, local_ptr: ValueRef, dest: ValueRef, ) { if bcx.sess().no_landing_pads() { bcx.call(func, &[data], None); bcx.store(C_null(Type::i8p(&bcx.ccx)), dest, None); } else if wants_msvc_seh(bcx.sess()) { trans_msvc_try(bcx, ccx, func, data, local_ptr, dest); } else { trans_gnu_try(bcx, ccx, 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 trans_msvc_try<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, ccx: &CrateContext, func: ValueRef, data: ValueRef, local_ptr: ValueRef, dest: ValueRef) { let llfn = get_rust_try_fn(ccx, &mut |bcx| { let ccx = bcx.ccx; bcx.set_personality_fn(bcx.ccx.eh_personality()); let normal = bcx.build_sibling_block("normal"); let catchswitch = bcx.build_sibling_block("catchswitch"); let catchpad = bcx.build_sibling_block("catchpad"); let caught = bcx.build_sibling_block("caught"); let func = llvm::get_param(bcx.llfn(), 0); let data = llvm::get_param(bcx.llfn(), 1); let local_ptr = llvm::get_param(bcx.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 // // 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 = Type::i64(ccx).ptr_to(); let slot = bcx.alloca(i64p, "slot", None); bcx.invoke(func, &[data], normal.llbb(), catchswitch.llbb(), None); normal.ret(C_i32(ccx, 0)); let cs = catchswitch.catch_switch(None, None, 1); catchswitch.add_handler(cs, catchpad.llbb()); let tcx = ccx.tcx(); let tydesc = match tcx.lang_items.msvc_try_filter() { Some(did) => ::consts::get_static(ccx, did), None => bug!("msvc_try_filter not defined"), }; let tok = catchpad.catch_pad(cs, &[tydesc, C_i32(ccx, 0), slot]); let addr = catchpad.load(slot, None); let arg1 = catchpad.load(addr, None); let val1 = C_i32(ccx, 1); let arg2 = catchpad.load(catchpad.inbounds_gep(addr, &[val1]), None); let local_ptr = catchpad.bitcast(local_ptr, i64p); catchpad.store(arg1, local_ptr, None); catchpad.store(arg2, catchpad.inbounds_gep(local_ptr, &[val1]), None); catchpad.catch_ret(tok, caught.llbb()); caught.ret(C_i32(ccx, 1)); }); // Note that no invoke is used here because by definition this function // can't panic (that's what it's catching). let ret = bcx.call(llfn, &[func, data, local_ptr], None); bcx.store(ret, dest, None); } // 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 translation 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 trans_gnu_try<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, ccx: &CrateContext, func: ValueRef, data: ValueRef, local_ptr: ValueRef, dest: ValueRef) { let llfn = get_rust_try_fn(ccx, &mut |bcx| { let ccx = bcx.ccx; // Translates the shims described above: // // bcx: // 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 then = bcx.build_sibling_block("then"); let catch = bcx.build_sibling_block("catch"); let func = llvm::get_param(bcx.llfn(), 0); let data = llvm::get_param(bcx.llfn(), 1); let local_ptr = llvm::get_param(bcx.llfn(), 2); bcx.invoke(func, &[data], then.llbb(), catch.llbb(), None); then.ret(C_i32(ccx, 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 = Type::struct_(ccx, &[Type::i8p(ccx), Type::i32(ccx)], false); let vals = catch.landing_pad(lpad_ty, bcx.ccx.eh_personality(), 1, catch.llfn()); catch.add_clause(vals, C_null(Type::i8p(ccx))); let ptr = catch.extract_value(vals, 0); catch.store(ptr, catch.bitcast(local_ptr, Type::i8p(ccx).ptr_to()), None); catch.ret(C_i32(ccx, 1)); }); // Note that no invoke is used here because by definition this function // can't panic (that's what it's catching). let ret = bcx.call(llfn, &[func, data, local_ptr], None); bcx.store(ret, dest, None); } // Helper function to give a Block to a closure to translate a shim function. // This is currently primarily used for the `try` intrinsic functions above. fn gen_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str, inputs: Vec>, output: Ty<'tcx>, trans: &mut for<'b> FnMut(Builder<'b, 'tcx>)) -> ValueRef { let rust_fn_ty = ccx.tcx().mk_fn_ptr(ty::Binder(ccx.tcx().mk_fn_sig( inputs.into_iter(), output, false, hir::Unsafety::Unsafe, Abi::Rust ))); let llfn = declare::define_internal_fn(ccx, name, rust_fn_ty); let bcx = Builder::new_block(ccx, llfn, "entry-block"); trans(bcx); llfn } // Helper function used to get a handle to the `__rust_try` function used to // catch exceptions. // // This function is only generated once and is then cached. fn get_rust_try_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, trans: &mut for<'b> FnMut(Builder<'b, 'tcx>)) -> ValueRef { if let Some(llfn) = ccx.rust_try_fn().get() { return llfn; } // Define the type up front for the signature of the rust_try function. let tcx = ccx.tcx(); let i8p = tcx.mk_mut_ptr(tcx.types.i8); let fn_ty = tcx.mk_fn_ptr(ty::Binder(tcx.mk_fn_sig( iter::once(i8p), tcx.mk_nil(), false, hir::Unsafety::Unsafe, Abi::Rust ))); let output = tcx.types.i32; let rust_try = gen_fn(ccx, "__rust_try", vec![fn_ty, i8p, i8p], output, trans); ccx.rust_try_fn().set(Some(rust_try)); return rust_try } fn span_invalid_monomorphization_error(a: &Session, b: Span, c: &str) { span_err!(a, b, E0511, "{}", c); } fn generic_simd_intrinsic<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, name: &str, callee_ty: Ty<'tcx>, llargs: &[ValueRef], ret_ty: Ty<'tcx>, llret_ty: Type, span: Span ) -> ValueRef { // macros for error handling: macro_rules! emit_error { ($msg: tt) => { emit_error!($msg, ) }; ($msg: tt, $($fmt: tt)*) => { span_invalid_monomorphization_error( bcx.sess(), span, &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg), name, $($fmt)*)); } } macro_rules! require { ($cond: expr, $($fmt: tt)*) => { if !$cond { emit_error!($($fmt)*); return C_nil(bcx.ccx) } } } macro_rules! require_simd { ($ty: expr, $position: expr) => { require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty) } } let tcx = bcx.tcx(); let sig = tcx.erase_late_bound_regions_and_normalize(&callee_ty.fn_sig(tcx)); let arg_tys = sig.inputs(); // every intrinsic takes a SIMD vector as its first argument require_simd!(arg_tys[0], "input"); let in_ty = arg_tys[0]; let in_elem = arg_tys[0].simd_type(tcx); let in_len = arg_tys[0].simd_size(tcx); let comparison = match name { "simd_eq" => Some(hir::BiEq), "simd_ne" => Some(hir::BiNe), "simd_lt" => Some(hir::BiLt), "simd_le" => Some(hir::BiLe), "simd_gt" => Some(hir::BiGt), "simd_ge" => Some(hir::BiGe), _ => None }; if let Some(cmp_op) = comparison { require_simd!(ret_ty, "return"); let out_len = ret_ty.simd_size(tcx); require!(in_len == out_len, "expected return type with length {} (same as input type `{}`), \ found `{}` with length {}", in_len, in_ty, ret_ty, out_len); require!(llret_ty.element_type().kind() == llvm::Integer, "expected return type with integer elements, found `{}` with non-integer `{}`", ret_ty, ret_ty.simd_type(tcx)); return compare_simd_types(bcx, llargs[0], llargs[1], in_elem, llret_ty, cmp_op) } if name.starts_with("simd_shuffle") { let n: usize = match name["simd_shuffle".len()..].parse() { Ok(n) => n, Err(_) => span_bug!(span, "bad `simd_shuffle` instruction only caught in trans?") }; require_simd!(ret_ty, "return"); let out_len = ret_ty.simd_size(tcx); require!(out_len == n, "expected return type of length {}, found `{}` with length {}", n, ret_ty, out_len); require!(in_elem == ret_ty.simd_type(tcx), "expected return element type `{}` (element of input `{}`), \ found `{}` with element type `{}`", in_elem, in_ty, ret_ty, ret_ty.simd_type(tcx)); let total_len = in_len as u128 * 2; let vector = llargs[2]; let indices: Option> = (0..n) .map(|i| { let arg_idx = i; let val = const_get_elt(vector, &[i as libc::c_uint]); match const_to_opt_u128(val, true) { None => { emit_error!("shuffle index #{} is not a constant", arg_idx); None } Some(idx) if idx >= total_len => { emit_error!("shuffle index #{} is out of bounds (limit {})", arg_idx, total_len); None } Some(idx) => Some(C_i32(bcx.ccx, idx as i32)), } }) .collect(); let indices = match indices { Some(i) => i, None => return C_null(llret_ty) }; return bcx.shuffle_vector(llargs[0], llargs[1], C_vector(&indices)) } if name == "simd_insert" { require!(in_elem == arg_tys[2], "expected inserted type `{}` (element of input `{}`), found `{}`", in_elem, in_ty, arg_tys[2]); return bcx.insert_element(llargs[0], llargs[2], llargs[1]) } if name == "simd_extract" { require!(ret_ty == in_elem, "expected return type `{}` (element of input `{}`), found `{}`", in_elem, in_ty, ret_ty); return bcx.extract_element(llargs[0], llargs[1]) } if name == "simd_cast" { require_simd!(ret_ty, "return"); let out_len = ret_ty.simd_size(tcx); require!(in_len == out_len, "expected return type with length {} (same as input type `{}`), \ found `{}` with length {}", in_len, in_ty, ret_ty, out_len); // casting cares about nominal type, not just structural type let out_elem = ret_ty.simd_type(tcx); if in_elem == out_elem { return llargs[0]; } enum Style { Float, Int(/* is signed? */ bool), Unsupported } let (in_style, in_width) = match in_elem.sty { // vectors of pointer-sized integers should've been // disallowed before here, so this unwrap is safe. ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()), ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()), ty::TyFloat(f) => (Style::Float, f.bit_width()), _ => (Style::Unsupported, 0) }; let (out_style, out_width) = match out_elem.sty { ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()), ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()), ty::TyFloat(f) => (Style::Float, f.bit_width()), _ => (Style::Unsupported, 0) }; match (in_style, out_style) { (Style::Int(in_is_signed), Style::Int(_)) => { return match in_width.cmp(&out_width) { Ordering::Greater => bcx.trunc(llargs[0], llret_ty), Ordering::Equal => llargs[0], Ordering::Less => if in_is_signed { bcx.sext(llargs[0], llret_ty) } else { bcx.zext(llargs[0], llret_ty) } } } (Style::Int(in_is_signed), Style::Float) => { return if in_is_signed { bcx.sitofp(llargs[0], llret_ty) } else { bcx.uitofp(llargs[0], llret_ty) } } (Style::Float, Style::Int(out_is_signed)) => { return if out_is_signed { bcx.fptosi(llargs[0], llret_ty) } else { bcx.fptoui(llargs[0], llret_ty) } } (Style::Float, Style::Float) => { return match in_width.cmp(&out_width) { Ordering::Greater => bcx.fptrunc(llargs[0], llret_ty), Ordering::Equal => llargs[0], Ordering::Less => bcx.fpext(llargs[0], llret_ty) } } _ => {/* Unsupported. Fallthrough. */} } require!(false, "unsupported cast from `{}` with element `{}` to `{}` with element `{}`", in_ty, in_elem, ret_ty, out_elem); } macro_rules! arith { ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => { $( if name == stringify!($name) { match in_elem.sty { $( $(ty::$p(_))|* => { return bcx.$call(llargs[0], llargs[1]) } )* _ => {}, } require!(false, "unsupported operation on `{}` with element `{}`", in_ty, in_elem) })* } } arith! { simd_add: TyUint, TyInt => add, TyFloat => fadd; simd_sub: TyUint, TyInt => sub, TyFloat => fsub; simd_mul: TyUint, TyInt => mul, TyFloat => fmul; simd_div: TyFloat => fdiv; simd_shl: TyUint, TyInt => shl; simd_shr: TyUint => lshr, TyInt => ashr; simd_and: TyUint, TyInt => and; simd_or: TyUint, TyInt => or; simd_xor: TyUint, TyInt => xor; } span_bug!(span, "unknown SIMD intrinsic"); } // Returns the width of an int TypeVariant, and if it's signed or not // Returns None if the type is not an integer // FIXME: there’s multiple of this functions, investigate using some of the already existing // stuffs. fn int_type_width_signed<'tcx>(sty: &ty::TypeVariants<'tcx>, ccx: &CrateContext) -> Option<(u64, bool)> { use rustc::ty::{TyInt, TyUint}; match *sty { TyInt(t) => Some((match t { ast::IntTy::Is => { match &ccx.tcx().sess.target.target.target_pointer_width[..] { "16" => 16, "32" => 32, "64" => 64, tws => bug!("Unsupported target word size for isize: {}", tws), } }, ast::IntTy::I8 => 8, ast::IntTy::I16 => 16, ast::IntTy::I32 => 32, ast::IntTy::I64 => 64, ast::IntTy::I128 => 128, }, true)), TyUint(t) => Some((match t { ast::UintTy::Us => { match &ccx.tcx().sess.target.target.target_pointer_width[..] { "16" => 16, "32" => 32, "64" => 64, tws => bug!("Unsupported target word size for usize: {}", tws), } }, ast::UintTy::U8 => 8, ast::UintTy::U16 => 16, ast::UintTy::U32 => 32, ast::UintTy::U64 => 64, ast::UintTy::U128 => 128, }, false)), _ => None, } } // Returns the width of a float TypeVariant // Returns None if the type is not a float fn float_type_width<'tcx>(sty: &ty::TypeVariants<'tcx>) -> Option { use rustc::ty::TyFloat; match *sty { TyFloat(t) => Some(match t { ast::FloatTy::F32 => 32, ast::FloatTy::F64 => 64, }), _ => None, } }