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base.rs
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// 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.
//! Codegen the completed AST to the LLVM IR.
//!
//! Some functions here, such as codegen_block and codegen_expr, return a value --
//! the result of the codegen to LLVM -- while others, such as codegen_fn
//! and mono_item, are called only for the side effect of adding a
//! particular definition to the LLVM IR output we're producing.
//!
//! Hopefully useful general knowledge about codegen:
//!
//! * There's no way to find out the Ty type of a ValueRef. Doing so
//! would be "trying to get the eggs out of an omelette" (credit:
//! pcwalton). You can, instead, find out its TypeRef by calling val_ty,
//! but one TypeRef corresponds to many `Ty`s; for instance, tup(int, int,
//! int) and rec(x=int, y=int, z=int) will have the same TypeRef.
use super::ModuleLlvm;
use super::ModuleSource;
use super::ModuleCodegen;
use super::ModuleKind;
use abi;
use back::link;
use back::write::{self, OngoingCodegen, create_target_machine};
use llvm::{ContextRef, ModuleRef, ValueRef, Vector, get_param};
use llvm;
use metadata;
use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
use rustc::middle::lang_items::StartFnLangItem;
use rustc::middle::weak_lang_items;
use rustc::mir::mono::{Linkage, Visibility, Stats};
use rustc::middle::cstore::{EncodedMetadata};
use rustc::ty::{self, Ty, TyCtxt};
use rustc::ty::layout::{self, Align, TyLayout, LayoutOf};
use rustc::ty::maps::Providers;
use rustc::dep_graph::{DepNode, DepConstructor};
use rustc::middle::cstore::{self, LinkMeta, LinkagePreference};
use rustc::middle::exported_symbols;
use rustc::util::common::{time, print_time_passes_entry};
use rustc::session::config::{self, NoDebugInfo};
use rustc::session::Session;
use rustc_incremental;
use allocator;
use mir::place::PlaceRef;
use attributes;
use builder::{Builder, MemFlags};
use callee;
use common::{C_bool, C_bytes_in_context, C_i32, C_usize};
use rustc_mir::monomorphize::collector::{self, MonoItemCollectionMode};
use common::{self, C_struct_in_context, C_array, val_ty};
use consts;
use context::{self, CodegenCx};
use debuginfo;
use declare;
use meth;
use mir;
use monomorphize::Instance;
use monomorphize::partitioning::{self, PartitioningStrategy, CodegenUnit, CodegenUnitExt};
use rustc_codegen_utils::symbol_names_test;
use time_graph;
use mono_item::{MonoItem, BaseMonoItemExt, MonoItemExt, DefPathBasedNames};
use type_::Type;
use type_of::LayoutLlvmExt;
use rustc::util::nodemap::{FxHashMap, FxHashSet, DefIdSet};
use CrateInfo;
use rustc_data_structures::sync::Lrc;
use rustc_target::spec::TargetTriple;
use std::any::Any;
use std::collections::BTreeMap;
use std::ffi::CString;
use std::str;
use std::sync::Arc;
use std::time::{Instant, Duration};
use std::i32;
use std::cmp;
use std::sync::mpsc;
use syntax_pos::Span;
use syntax_pos::symbol::InternedString;
use syntax::attr;
use rustc::hir;
use syntax::ast;
use mir::operand::OperandValue;
pub use rustc_codegen_utils::check_for_rustc_errors_attr;
pub struct StatRecorder<'a, 'tcx: 'a> {
cx: &'a CodegenCx<'a, 'tcx>,
name: Option<String>,
istart: usize,
}
impl<'a, 'tcx> StatRecorder<'a, 'tcx> {
pub fn new(cx: &'a CodegenCx<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> {
let istart = cx.stats.borrow().n_llvm_insns;
StatRecorder {
cx,
name: Some(name),
istart,
}
}
}
impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> {
fn drop(&mut self) {
if self.cx.sess().codegen_stats() {
let mut stats = self.cx.stats.borrow_mut();
let iend = stats.n_llvm_insns;
stats.fn_stats.push((self.name.take().unwrap(), iend - self.istart));
stats.n_fns += 1;
// Reset LLVM insn count to avoid compound costs.
stats.n_llvm_insns = self.istart;
}
}
}
pub fn bin_op_to_icmp_predicate(op: hir::BinOp_,
signed: bool)
-> llvm::IntPredicate {
match op {
hir::BiEq => llvm::IntEQ,
hir::BiNe => llvm::IntNE,
hir::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT },
hir::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE },
hir::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT },
hir::BiGe => if signed { llvm::IntSGE } else { llvm::IntUGE },
op => {
bug!("comparison_op_to_icmp_predicate: expected comparison operator, \
found {:?}",
op)
}
}
}
pub fn bin_op_to_fcmp_predicate(op: hir::BinOp_) -> llvm::RealPredicate {
match op {
hir::BiEq => llvm::RealOEQ,
hir::BiNe => llvm::RealUNE,
hir::BiLt => llvm::RealOLT,
hir::BiLe => llvm::RealOLE,
hir::BiGt => llvm::RealOGT,
hir::BiGe => llvm::RealOGE,
op => {
bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \
found {:?}",
op);
}
}
}
pub fn compare_simd_types<'a, 'tcx>(
bx: &Builder<'a, 'tcx>,
lhs: ValueRef,
rhs: ValueRef,
t: Ty<'tcx>,
ret_ty: Type,
op: hir::BinOp_
) -> ValueRef {
let signed = match t.sty {
ty::TyFloat(_) => {
let cmp = bin_op_to_fcmp_predicate(op);
return bx.sext(bx.fcmp(cmp, lhs, rhs), ret_ty);
},
ty::TyUint(_) => false,
ty::TyInt(_) => true,
_ => bug!("compare_simd_types: invalid SIMD type"),
};
let cmp = bin_op_to_icmp_predicate(op, signed);
// LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
// to get the correctly sized type. This will compile to a single instruction
// once the IR is converted to assembly if the SIMD instruction is supported
// by the target architecture.
bx.sext(bx.icmp(cmp, lhs, rhs), ret_ty)
}
/// Retrieve the information we are losing (making dynamic) in an unsizing
/// adjustment.
///
/// The `old_info` argument is a bit funny. It is intended for use
/// in an upcast, where the new vtable for an object will be derived
/// from the old one.
pub fn unsized_info<'cx, 'tcx>(cx: &CodegenCx<'cx, 'tcx>,
source: Ty<'tcx>,
target: Ty<'tcx>,
old_info: Option<ValueRef>)
-> ValueRef {
let (source, target) = cx.tcx.struct_lockstep_tails(source, target);
match (&source.sty, &target.sty) {
(&ty::TyArray(_, len), &ty::TySlice(_)) => {
C_usize(cx, len.unwrap_usize(cx.tcx))
}
(&ty::TyDynamic(..), &ty::TyDynamic(..)) => {
// For now, upcasts are limited to changes in marker
// traits, and hence never actually require an actual
// change to the vtable.
old_info.expect("unsized_info: missing old info for trait upcast")
}
(_, &ty::TyDynamic(ref data, ..)) => {
let vtable_ptr = cx.layout_of(cx.tcx.mk_mut_ptr(target))
.field(cx, abi::FAT_PTR_EXTRA);
consts::ptrcast(meth::get_vtable(cx, source, data.principal()),
vtable_ptr.llvm_type(cx))
}
_ => bug!("unsized_info: invalid unsizing {:?} -> {:?}",
source,
target),
}
}
/// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
pub fn unsize_thin_ptr<'a, 'tcx>(
bx: &Builder<'a, 'tcx>,
src: ValueRef,
src_ty: Ty<'tcx>,
dst_ty: Ty<'tcx>
) -> (ValueRef, ValueRef) {
debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
match (&src_ty.sty, &dst_ty.sty) {
(&ty::TyRef(_, a, _),
&ty::TyRef(_, b, _)) |
(&ty::TyRef(_, a, _),
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
(&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
assert!(bx.cx.type_is_sized(a));
let ptr_ty = bx.cx.layout_of(b).llvm_type(bx.cx).ptr_to();
(bx.pointercast(src, ptr_ty), unsized_info(bx.cx, a, b, None))
}
(&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
let (a, b) = (src_ty.boxed_ty(), dst_ty.boxed_ty());
assert!(bx.cx.type_is_sized(a));
let ptr_ty = bx.cx.layout_of(b).llvm_type(bx.cx).ptr_to();
(bx.pointercast(src, ptr_ty), unsized_info(bx.cx, a, b, None))
}
(&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) => {
assert_eq!(def_a, def_b);
let src_layout = bx.cx.layout_of(src_ty);
let dst_layout = bx.cx.layout_of(dst_ty);
let mut result = None;
for i in 0..src_layout.fields.count() {
let src_f = src_layout.field(bx.cx, i);
assert_eq!(src_layout.fields.offset(i).bytes(), 0);
assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
if src_f.is_zst() {
continue;
}
assert_eq!(src_layout.size, src_f.size);
let dst_f = dst_layout.field(bx.cx, i);
assert_ne!(src_f.ty, dst_f.ty);
assert_eq!(result, None);
result = Some(unsize_thin_ptr(bx, src, src_f.ty, dst_f.ty));
}
let (lldata, llextra) = result.unwrap();
// HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
(bx.bitcast(lldata, dst_layout.scalar_pair_element_llvm_type(bx.cx, 0)),
bx.bitcast(llextra, dst_layout.scalar_pair_element_llvm_type(bx.cx, 1)))
}
_ => bug!("unsize_thin_ptr: called on bad types"),
}
}
/// Coerce `src`, which is a reference to a value of type `src_ty`,
/// to a value of type `dst_ty` and store the result in `dst`
pub fn coerce_unsized_into<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
src: PlaceRef<'tcx>,
dst: PlaceRef<'tcx>) {
let src_ty = src.layout.ty;
let dst_ty = dst.layout.ty;
let coerce_ptr = || {
let (base, info) = match src.load(bx).val {
OperandValue::Pair(base, info) => {
// fat-ptr to fat-ptr unsize preserves the vtable
// i.e. &'a fmt::Debug+Send => &'a fmt::Debug
// So we need to pointercast the base to ensure
// the types match up.
let thin_ptr = dst.layout.field(bx.cx, abi::FAT_PTR_ADDR);
(bx.pointercast(base, thin_ptr.llvm_type(bx.cx)), info)
}
OperandValue::Immediate(base) => {
unsize_thin_ptr(bx, base, src_ty, dst_ty)
}
OperandValue::Ref(..) => bug!()
};
OperandValue::Pair(base, info).store(bx, dst);
};
match (&src_ty.sty, &dst_ty.sty) {
(&ty::TyRef(..), &ty::TyRef(..)) |
(&ty::TyRef(..), &ty::TyRawPtr(..)) |
(&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => {
coerce_ptr()
}
(&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
coerce_ptr()
}
(&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) => {
assert_eq!(def_a, def_b);
for i in 0..def_a.variants[0].fields.len() {
let src_f = src.project_field(bx, i);
let dst_f = dst.project_field(bx, i);
if dst_f.layout.is_zst() {
continue;
}
if src_f.layout.ty == dst_f.layout.ty {
memcpy_ty(bx, dst_f.llval, src_f.llval, src_f.layout,
src_f.align.min(dst_f.align), MemFlags::empty());
} else {
coerce_unsized_into(bx, src_f, dst_f);
}
}
}
_ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
src_ty,
dst_ty),
}
}
pub fn cast_shift_expr_rhs(
cx: &Builder, op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef
) -> ValueRef {
cast_shift_rhs(op, lhs, rhs, |a, b| cx.trunc(a, b), |a, b| cx.zext(a, b))
}
fn cast_shift_rhs<F, G>(op: hir::BinOp_,
lhs: ValueRef,
rhs: ValueRef,
trunc: F,
zext: G)
-> ValueRef
where F: FnOnce(ValueRef, Type) -> ValueRef,
G: FnOnce(ValueRef, Type) -> ValueRef
{
// Shifts may have any size int on the rhs
if op.is_shift() {
let mut rhs_llty = val_ty(rhs);
let mut lhs_llty = val_ty(lhs);
if rhs_llty.kind() == Vector {
rhs_llty = rhs_llty.element_type()
}
if lhs_llty.kind() == Vector {
lhs_llty = lhs_llty.element_type()
}
let rhs_sz = rhs_llty.int_width();
let lhs_sz = lhs_llty.int_width();
if lhs_sz < rhs_sz {
trunc(rhs, lhs_llty)
} else if lhs_sz > rhs_sz {
// FIXME (#1877: If shifting by negative
// values becomes not undefined then this is wrong.
zext(rhs, lhs_llty)
} else {
rhs
}
} else {
rhs
}
}
/// Returns whether this session's target will use SEH-based unwinding.
///
/// This is only true for MSVC targets, and even then the 64-bit MSVC target
/// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
/// 64-bit MinGW) instead of "full SEH".
pub fn wants_msvc_seh(sess: &Session) -> bool {
sess.target.target.options.is_like_msvc
}
pub fn call_assume<'a, 'tcx>(bx: &Builder<'a, 'tcx>, val: ValueRef) {
let assume_intrinsic = bx.cx.get_intrinsic("llvm.assume");
bx.call(assume_intrinsic, &[val], None);
}
pub fn from_immediate(bx: &Builder, val: ValueRef) -> ValueRef {
if val_ty(val) == Type::i1(bx.cx) {
bx.zext(val, Type::i8(bx.cx))
} else {
val
}
}
pub fn to_immediate(bx: &Builder, val: ValueRef, layout: layout::TyLayout) -> ValueRef {
if let layout::Abi::Scalar(ref scalar) = layout.abi {
if scalar.is_bool() {
return bx.trunc(val, Type::i1(bx.cx));
}
}
val
}
pub fn call_memcpy(bx: &Builder,
dst: ValueRef,
src: ValueRef,
n_bytes: ValueRef,
align: Align,
flags: MemFlags) {
if flags.contains(MemFlags::NONTEMPORAL) {
// HACK(nox): This is inefficient but there is no nontemporal memcpy.
let val = bx.load(src, align);
let ptr = bx.pointercast(dst, val_ty(val).ptr_to());
bx.store_with_flags(val, ptr, align, flags);
return;
}
let cx = bx.cx;
let ptr_width = &cx.sess().target.target.target_pointer_width;
let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width);
let memcpy = cx.get_intrinsic(&key);
let src_ptr = bx.pointercast(src, Type::i8p(cx));
let dst_ptr = bx.pointercast(dst, Type::i8p(cx));
let size = bx.intcast(n_bytes, cx.isize_ty, false);
let align = C_i32(cx, align.abi() as i32);
let volatile = C_bool(cx, flags.contains(MemFlags::VOLATILE));
bx.call(memcpy, &[dst_ptr, src_ptr, size, align, volatile], None);
}
pub fn memcpy_ty<'a, 'tcx>(
bx: &Builder<'a, 'tcx>,
dst: ValueRef,
src: ValueRef,
layout: TyLayout<'tcx>,
align: Align,
flags: MemFlags,
) {
let size = layout.size.bytes();
if size == 0 {
return;
}
call_memcpy(bx, dst, src, C_usize(bx.cx, size), align, flags);
}
pub fn call_memset<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
ptr: ValueRef,
fill_byte: ValueRef,
size: ValueRef,
align: ValueRef,
volatile: bool) -> ValueRef {
let ptr_width = &bx.cx.sess().target.target.target_pointer_width;
let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width);
let llintrinsicfn = bx.cx.get_intrinsic(&intrinsic_key);
let volatile = C_bool(bx.cx, volatile);
bx.call(llintrinsicfn, &[ptr, fill_byte, size, align, volatile], None)
}
pub fn codegen_instance<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>, instance: Instance<'tcx>) {
let _s = if cx.sess().codegen_stats() {
let mut instance_name = String::new();
DefPathBasedNames::new(cx.tcx, true, true)
.push_def_path(instance.def_id(), &mut instance_name);
Some(StatRecorder::new(cx, instance_name))
} else {
None
};
// this is an info! to allow collecting monomorphization statistics
// and to allow finding the last function before LLVM aborts from
// release builds.
info!("codegen_instance({})", instance);
let fn_ty = instance.ty(cx.tcx);
let sig = common::ty_fn_sig(cx, fn_ty);
let sig = cx.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
let lldecl = match cx.instances.borrow().get(&instance) {
Some(&val) => val,
None => bug!("Instance `{:?}` not already declared", instance)
};
cx.stats.borrow_mut().n_closures += 1;
// The `uwtable` attribute according to LLVM is:
//
// This attribute indicates that the ABI being targeted requires that an
// unwind table entry be produced for this function even if we can show
// that no exceptions passes by it. This is normally the case for the
// ELF x86-64 abi, but it can be disabled for some compilation units.
//
// Typically when we're compiling with `-C panic=abort` (which implies this
// `no_landing_pads` check) we don't need `uwtable` because we can't
// generate any exceptions! On Windows, however, exceptions include other
// events such as illegal instructions, segfaults, etc. This means that on
// Windows we end up still needing the `uwtable` attribute even if the `-C
// panic=abort` flag is passed.
//
// You can also find more info on why Windows is whitelisted here in:
// https://bugzilla.mozilla.org/show_bug.cgi?id=1302078
if !cx.sess().no_landing_pads() ||
cx.sess().target.target.options.requires_uwtable {
attributes::emit_uwtable(lldecl, true);
}
let mir = cx.tcx.instance_mir(instance.def);
mir::codegen_mir(cx, lldecl, &mir, instance, sig);
}
pub fn set_link_section(cx: &CodegenCx,
llval: ValueRef,
attrs: &[ast::Attribute]) {
if let Some(sect) = attr::first_attr_value_str_by_name(attrs, "link_section") {
if contains_null(§.as_str()) {
cx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", §));
}
unsafe {
let buf = CString::new(sect.as_str().as_bytes()).unwrap();
llvm::LLVMSetSection(llval, buf.as_ptr());
}
}
}
/// Create the `main` function which will initialize the rust runtime and call
/// users main function.
fn maybe_create_entry_wrapper(cx: &CodegenCx) {
if let Some(ref et) = cx.sess().entry_fn.get() {
let main_def_id = et.get_def_id(&cx.tcx.hir);
let span = et.get_span();
let instance = Instance::mono(cx.tcx, main_def_id);
if !cx.codegen_unit.contains_item(&MonoItem::Fn(instance)) {
// We want to create the wrapper in the same codegen unit as Rust's main
// function.
return;
}
let main_llfn = callee::get_fn(cx, instance);
match et {
config::EntryImported(..)
| config::EntryMain(..) => create_entry_fn(cx, span, main_llfn, main_def_id, true),
config::EntryStart(..) => create_entry_fn(cx, span, main_llfn, main_def_id, false),
}
}
fn create_entry_fn<'cx>(cx: &'cx CodegenCx,
sp: Span,
rust_main: ValueRef,
rust_main_def_id: DefId,
use_start_lang_item: bool) {
let llfty = Type::func(&[Type::c_int(cx), Type::i8p(cx).ptr_to()], &Type::c_int(cx));
let main_ret_ty = cx.tcx.fn_sig(rust_main_def_id).output();
// Given that `main()` has no arguments,
// then its return type cannot have
// late-bound regions, since late-bound
// regions must appear in the argument
// listing.
let main_ret_ty = cx.tcx.erase_regions(
&main_ret_ty.no_late_bound_regions().unwrap(),
);
if declare::get_defined_value(cx, "main").is_some() {
// FIXME: We should be smart and show a better diagnostic here.
cx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
.help("did you use #[no_mangle] on `fn main`? Use #[start] instead")
.emit();
cx.sess().abort_if_errors();
bug!();
}
let llfn = declare::declare_cfn(cx, "main", llfty);
// `main` should respect same config for frame pointer elimination as rest of code
attributes::set_frame_pointer_elimination(cx, llfn);
let bx = Builder::new_block(cx, llfn, "top");
debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(&bx);
// Params from native main() used as args for rust start function
let param_argc = get_param(llfn, 0);
let param_argv = get_param(llfn, 1);
let arg_argc = bx.intcast(param_argc, cx.isize_ty, true);
let arg_argv = param_argv;
let (start_fn, args) = if use_start_lang_item {
let start_def_id = cx.tcx.require_lang_item(StartFnLangItem);
let start_fn = callee::resolve_and_get_fn(
cx,
start_def_id,
cx.tcx.intern_substs(&[main_ret_ty.into()]),
);
(start_fn, vec![bx.pointercast(rust_main, Type::i8p(cx).ptr_to()),
arg_argc, arg_argv])
} else {
debug!("using user-defined start fn");
(rust_main, vec![arg_argc, arg_argv])
};
let result = bx.call(start_fn, &args, None);
bx.ret(bx.intcast(result, Type::c_int(cx), true));
}
}
fn contains_null(s: &str) -> bool {
s.bytes().any(|b| b == 0)
}
fn write_metadata<'a, 'gcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
llmod_id: &str,
link_meta: &LinkMeta)
-> (ContextRef, ModuleRef, EncodedMetadata) {
use std::io::Write;
use flate2::Compression;
use flate2::write::DeflateEncoder;
let (metadata_llcx, metadata_llmod) = unsafe {
context::create_context_and_module(tcx.sess, llmod_id)
};
#[derive(PartialEq, Eq, PartialOrd, Ord)]
enum MetadataKind {
None,
Uncompressed,
Compressed
}
let kind = tcx.sess.crate_types.borrow().iter().map(|ty| {
match *ty {
config::CrateTypeExecutable |
config::CrateTypeStaticlib |
config::CrateTypeCdylib => MetadataKind::None,
config::CrateTypeRlib => MetadataKind::Uncompressed,
config::CrateTypeDylib |
config::CrateTypeProcMacro => MetadataKind::Compressed,
}
}).max().unwrap_or(MetadataKind::None);
if kind == MetadataKind::None {
return (metadata_llcx,
metadata_llmod,
EncodedMetadata::new());
}
let metadata = tcx.encode_metadata(link_meta);
if kind == MetadataKind::Uncompressed {
return (metadata_llcx, metadata_llmod, metadata);
}
assert!(kind == MetadataKind::Compressed);
let mut compressed = tcx.metadata_encoding_version();
DeflateEncoder::new(&mut compressed, Compression::fast())
.write_all(&metadata.raw_data).unwrap();
let llmeta = C_bytes_in_context(metadata_llcx, &compressed);
let llconst = C_struct_in_context(metadata_llcx, &[llmeta], false);
let name = exported_symbols::metadata_symbol_name(tcx);
let buf = CString::new(name).unwrap();
let llglobal = unsafe {
llvm::LLVMAddGlobal(metadata_llmod, val_ty(llconst).to_ref(), buf.as_ptr())
};
unsafe {
llvm::LLVMSetInitializer(llglobal, llconst);
let section_name = metadata::metadata_section_name(&tcx.sess.target.target);
let name = CString::new(section_name).unwrap();
llvm::LLVMSetSection(llglobal, name.as_ptr());
// Also generate a .section directive to force no
// flags, at least for ELF outputs, so that the
// metadata doesn't get loaded into memory.
let directive = format!(".section {}", section_name);
let directive = CString::new(directive).unwrap();
llvm::LLVMSetModuleInlineAsm(metadata_llmod, directive.as_ptr())
}
return (metadata_llcx, metadata_llmod, metadata);
}
pub struct ValueIter {
cur: ValueRef,
step: unsafe extern "C" fn(ValueRef) -> ValueRef,
}
impl Iterator for ValueIter {
type Item = ValueRef;
fn next(&mut self) -> Option<ValueRef> {
let old = self.cur;
if !old.is_null() {
self.cur = unsafe { (self.step)(old) };
Some(old)
} else {
None
}
}
}
pub fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter {
unsafe {
ValueIter {
cur: llvm::LLVMGetFirstGlobal(llmod),
step: llvm::LLVMGetNextGlobal,
}
}
}
pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
rx: mpsc::Receiver<Box<Any + Send>>)
-> OngoingCodegen {
check_for_rustc_errors_attr(tcx);
if let Some(true) = tcx.sess.opts.debugging_opts.thinlto {
if unsafe { !llvm::LLVMRustThinLTOAvailable() } {
tcx.sess.fatal("this compiler's LLVM does not support ThinLTO");
}
}
if (tcx.sess.opts.debugging_opts.pgo_gen.is_some() ||
!tcx.sess.opts.debugging_opts.pgo_use.is_empty()) &&
unsafe { !llvm::LLVMRustPGOAvailable() }
{
tcx.sess.fatal("this compiler's LLVM does not support PGO");
}
let crate_hash = tcx.crate_hash(LOCAL_CRATE);
let link_meta = link::build_link_meta(crate_hash);
// Codegen the metadata.
let llmod_id = "metadata";
let (metadata_llcx, metadata_llmod, metadata) =
time(tcx.sess, "write metadata", || {
write_metadata(tcx, llmod_id, &link_meta)
});
let metadata_module = ModuleCodegen {
name: link::METADATA_MODULE_NAME.to_string(),
llmod_id: llmod_id.to_string(),
source: ModuleSource::Codegened(ModuleLlvm {
llcx: metadata_llcx,
llmod: metadata_llmod,
tm: create_target_machine(tcx.sess, false),
}),
kind: ModuleKind::Metadata,
};
let time_graph = if tcx.sess.opts.debugging_opts.codegen_time_graph {
Some(time_graph::TimeGraph::new())
} else {
None
};
// Skip crate items and just output metadata in -Z no-codegen mode.
if tcx.sess.opts.debugging_opts.no_codegen ||
!tcx.sess.opts.output_types.should_codegen() {
let ongoing_codegen = write::start_async_codegen(
tcx,
time_graph.clone(),
link_meta,
metadata,
rx,
1);
ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
ongoing_codegen.codegen_finished(tcx);
assert_and_save_dep_graph(tcx);
ongoing_codegen.check_for_errors(tcx.sess);
return ongoing_codegen;
}
// Run the monomorphization collector and partition the collected items into
// codegen units.
let codegen_units =
tcx.collect_and_partition_mono_items(LOCAL_CRATE).1;
let codegen_units = (*codegen_units).clone();
// Force all codegen_unit queries so they are already either red or green
// when compile_codegen_unit accesses them. We are not able to re-execute
// the codegen_unit query from just the DepNode, so an unknown color would
// lead to having to re-execute compile_codegen_unit, possibly
// unnecessarily.
if tcx.dep_graph.is_fully_enabled() {
for cgu in &codegen_units {
tcx.codegen_unit(cgu.name().clone());
}
}
let ongoing_codegen = write::start_async_codegen(
tcx,
time_graph.clone(),
link_meta,
metadata,
rx,
codegen_units.len());
// Codegen an allocator shim, if any
let allocator_module = if let Some(kind) = *tcx.sess.allocator_kind.get() {
unsafe {
let llmod_id = "allocator";
let (llcx, llmod) =
context::create_context_and_module(tcx.sess, llmod_id);
let modules = ModuleLlvm {
llmod,
llcx,
tm: create_target_machine(tcx.sess, false),
};
time(tcx.sess, "write allocator module", || {
allocator::codegen(tcx, &modules, kind)
});
Some(ModuleCodegen {
name: link::ALLOCATOR_MODULE_NAME.to_string(),
llmod_id: llmod_id.to_string(),
source: ModuleSource::Codegened(modules),
kind: ModuleKind::Allocator,
})
}
} else {
None
};
if let Some(allocator_module) = allocator_module {
ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module);
}
ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
// We sort the codegen units by size. This way we can schedule work for LLVM
// a bit more efficiently.
let codegen_units = {
let mut codegen_units = codegen_units;
codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
codegen_units
};
let mut total_codegen_time = Duration::new(0, 0);
let mut all_stats = Stats::default();
for cgu in codegen_units.into_iter() {
ongoing_codegen.wait_for_signal_to_codegen_item();
ongoing_codegen.check_for_errors(tcx.sess);
// First, if incremental compilation is enabled, we try to re-use the
// codegen unit from the cache.
if tcx.dep_graph.is_fully_enabled() {
let cgu_id = cgu.work_product_id();
// Check whether there is a previous work-product we can
// re-use. Not only must the file exist, and the inputs not
// be dirty, but the hash of the symbols we will generate must
// be the same.
if let Some(buf) = tcx.dep_graph.previous_work_product(&cgu_id) {
let dep_node = &DepNode::new(tcx,
DepConstructor::CompileCodegenUnit(cgu.name().clone()));
// We try to mark the DepNode::CompileCodegenUnit green. If we
// succeed it means that none of the dependencies has changed
// and we can safely re-use.
if let Some(dep_node_index) = tcx.dep_graph.try_mark_green(tcx, dep_node) {
// Append ".rs" to LLVM module identifier.
//
// LLVM code generator emits a ".file filename" directive
// for ELF backends. Value of the "filename" is set as the
// LLVM module identifier. Due to a LLVM MC bug[1], LLVM
// crashes if the module identifier is same as other symbols
// such as a function name in the module.
// 1. http://llvm.org/bugs/show_bug.cgi?id=11479
let llmod_id = format!("{}.rs", cgu.name());
let module = ModuleCodegen {
name: cgu.name().to_string(),
source: ModuleSource::Preexisting(buf),
kind: ModuleKind::Regular,
llmod_id,
};
tcx.dep_graph.mark_loaded_from_cache(dep_node_index, true);
write::submit_codegened_module_to_llvm(tcx, module, 0);
// Continue to next cgu, this one is done.
continue
}
} else {
// This can happen if files were deleted from the cache
// directory for some reason. We just re-compile then.
}
}
let _timing_guard = time_graph.as_ref().map(|time_graph| {
time_graph.start(write::CODEGEN_WORKER_TIMELINE,
write::CODEGEN_WORK_PACKAGE_KIND,
&format!("codegen {}", cgu.name()))
});
let start_time = Instant::now();
all_stats.extend(tcx.compile_codegen_unit(*cgu.name()));
total_codegen_time += start_time.elapsed();
ongoing_codegen.check_for_errors(tcx.sess);
}
ongoing_codegen.codegen_finished(tcx);
// Since the main thread is sometimes blocked during codegen, we keep track
// -Ztime-passes output manually.
print_time_passes_entry(tcx.sess.time_passes(),
"codegen to LLVM IR",
total_codegen_time);
if tcx.sess.opts.incremental.is_some() {
::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
}
symbol_names_test::report_symbol_names(tcx);
if tcx.sess.codegen_stats() {
println!("--- codegen stats ---");
println!("n_glues_created: {}", all_stats.n_glues_created);
println!("n_null_glues: {}", all_stats.n_null_glues);
println!("n_real_glues: {}", all_stats.n_real_glues);
println!("n_fns: {}", all_stats.n_fns);
println!("n_inlines: {}", all_stats.n_inlines);
println!("n_closures: {}", all_stats.n_closures);
println!("fn stats:");
all_stats.fn_stats.sort_by_key(|&(_, insns)| insns);
for &(ref name, insns) in all_stats.fn_stats.iter() {
println!("{} insns, {}", insns, *name);
}
}
if tcx.sess.count_llvm_insns() {
for (k, v) in all_stats.llvm_insns.iter() {
println!("{:7} {}", *v, *k);
}
}
ongoing_codegen.check_for_errors(tcx.sess);
assert_and_save_dep_graph(tcx);
ongoing_codegen
}
fn assert_and_save_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
time(tcx.sess,
"assert dep graph",
|| rustc_incremental::assert_dep_graph(tcx));
time(tcx.sess,
"serialize dep graph",
|| rustc_incremental::save_dep_graph(tcx));
}
fn collect_and_partition_mono_items<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
cnum: CrateNum,
) -> (Arc<DefIdSet>, Arc<Vec<Arc<CodegenUnit<'tcx>>>>)
{
assert_eq!(cnum, LOCAL_CRATE);
let collection_mode = match tcx.sess.opts.debugging_opts.print_mono_items {
Some(ref s) => {
let mode_string = s.to_lowercase();
let mode_string = mode_string.trim();
if mode_string == "eager" {
MonoItemCollectionMode::Eager
} else {
if mode_string != "lazy" {
let message = format!("Unknown codegen-item collection mode '{}'. \
Falling back to 'lazy' mode.",
mode_string);
tcx.sess.warn(&message);
}
MonoItemCollectionMode::Lazy
}
}
None => {
if tcx.sess.opts.cg.link_dead_code {
MonoItemCollectionMode::Eager
} else {
MonoItemCollectionMode::Lazy
}
}
};
let (items, inlining_map) =
time(tcx.sess, "monomorphization collection", || {
collector::collect_crate_mono_items(tcx, collection_mode)
});
tcx.sess.abort_if_errors();
::rustc_mir::monomorphize::assert_symbols_are_distinct(tcx, items.iter());
let strategy = if tcx.sess.opts.incremental.is_some() {
PartitioningStrategy::PerModule