rust/src/librustc_codegen_llvm/base.rs

1198 lines
42 KiB
Rust

// 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 Value. Doing so
//! would be "trying to get the eggs out of an omelette" (credit:
//! pcwalton). You can, instead, find out its llvm::Type by calling val_ty,
//! but one llvm::Type corresponds to many `Ty`s; for instance, tup(int, int,
//! int) and rec(x=int, y=int, z=int) will have the same llvm::Type.
use super::ModuleLlvm;
use rustc_codegen_ssa::{ModuleCodegen, ModuleKind, CachedModuleCodegen};
use super::LlvmCodegenBackend;
use abi;
use back::write;
use llvm;
use metadata;
use rustc::dep_graph::cgu_reuse_tracker::CguReuse;
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, CodegenUnitNameBuilder};
use rustc::middle::cstore::{EncodedMetadata};
use rustc::ty::{self, Ty, TyCtxt};
use rustc::ty::layout::{self, Align, TyLayout, LayoutOf, VariantIdx, HasTyCtxt};
use rustc::ty::query::Providers;
use rustc::middle::cstore::{self, LinkagePreference};
use rustc::middle::exported_symbols;
use rustc::util::common::{time, print_time_passes_entry};
use rustc::util::profiling::ProfileCategory;
use rustc::session::config::{self, DebugInfo, EntryFnType, Lto};
use rustc::session::Session;
use rustc_incremental;
use mir::place::PlaceRef;
use builder::{Builder, MemFlags};
use callee;
use rustc_mir::monomorphize::item::DefPathBasedNames;
use common;
use rustc_codegen_ssa::common::{RealPredicate, TypeKind, IntPredicate};
use meth;
use mir;
use context::CodegenCx;
use monomorphize::Instance;
use monomorphize::partitioning::{CodegenUnit, CodegenUnitExt};
use rustc_codegen_utils::symbol_names_test;
use time_graph;
use mono_item::{MonoItem, MonoItemExt};
use rustc::util::nodemap::FxHashMap;
use CrateInfo;
use rustc_data_structures::small_c_str::SmallCStr;
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::indexed_vec::Idx;
use interfaces::*;
use std::any::Any;
use std::cmp;
use std::ffi::CString;
use std::marker;
use std::ops::{Deref, DerefMut};
use std::sync::mpsc;
use std::time::{Instant, Duration};
use syntax_pos::Span;
use syntax_pos::symbol::InternedString;
use syntax::attr;
use rustc::hir::{self, CodegenFnAttrs};
use value::Value;
use mir::operand::OperandValue;
use rustc_codegen_utils::check_for_rustc_errors_attr;
pub struct StatRecorder<'a, 'tcx, Cx: 'a + CodegenMethods<'tcx>> {
cx: &'a Cx,
name: Option<String>,
istart: usize,
_marker: marker::PhantomData<&'tcx ()>,
}
impl<'a, 'tcx, Cx: CodegenMethods<'tcx>> StatRecorder<'a, 'tcx, Cx> {
pub fn new(cx: &'a Cx, name: String) -> Self {
let istart = cx.stats().borrow().n_llvm_insns;
StatRecorder {
cx,
name: Some(name),
istart,
_marker: marker::PhantomData,
}
}
}
impl<'a, 'tcx, Cx: CodegenMethods<'tcx>> Drop for StatRecorder<'a, 'tcx, Cx> {
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::BinOpKind,
signed: bool)
-> IntPredicate {
match op {
hir::BinOpKind::Eq => IntPredicate::IntEQ,
hir::BinOpKind::Ne => IntPredicate::IntNE,
hir::BinOpKind::Lt => if signed { IntPredicate::IntSLT } else { IntPredicate::IntULT },
hir::BinOpKind::Le => if signed { IntPredicate::IntSLE } else { IntPredicate::IntULE },
hir::BinOpKind::Gt => if signed { IntPredicate::IntSGT } else { IntPredicate::IntUGT },
hir::BinOpKind::Ge => if signed { IntPredicate::IntSGE } else { IntPredicate::IntUGE },
op => {
bug!("comparison_op_to_icmp_predicate: expected comparison operator, \
found {:?}",
op)
}
}
}
pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate {
match op {
hir::BinOpKind::Eq => RealPredicate::RealOEQ,
hir::BinOpKind::Ne => RealPredicate::RealUNE,
hir::BinOpKind::Lt => RealPredicate::RealOLT,
hir::BinOpKind::Le => RealPredicate::RealOLE,
hir::BinOpKind::Gt => RealPredicate::RealOGT,
hir::BinOpKind::Ge => RealPredicate::RealOGE,
op => {
bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \
found {:?}",
op);
}
}
}
pub fn compare_simd_types<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
lhs: Bx::Value,
rhs: Bx::Value,
t: Ty<'tcx>,
ret_ty: Bx::Type,
op: hir::BinOpKind
) -> Bx::Value {
let signed = match t.sty {
ty::Float(_) => {
let cmp = bin_op_to_fcmp_predicate(op);
return bx.sext(bx.fcmp(cmp, lhs, rhs), ret_ty);
},
ty::Uint(_) => false,
ty::Int(_) => 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<'tcx, Cx: CodegenMethods<'tcx>>(
cx: &Cx,
source: Ty<'tcx>,
target: Ty<'tcx>,
old_info: Option<Cx::Value>,
) -> Cx::Value {
let (source, target) = cx.tcx().struct_lockstep_tails(source, target);
match (&source.sty, &target.sty) {
(&ty::Array(_, len), &ty::Slice(_)) => {
cx.const_usize(len.unwrap_usize(cx.tcx()))
}
(&ty::Dynamic(..), &ty::Dynamic(..)) => {
// 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::Dynamic(ref data, ..)) => {
let vtable_ptr = cx.layout_of(cx.tcx().mk_mut_ptr(target))
.field(cx, abi::FAT_PTR_EXTRA);
cx.static_ptrcast(meth::get_vtable(cx, source, data.principal()),
cx.backend_type(vtable_ptr))
}
_ => 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: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
src: Bx::Value,
src_ty: Ty<'tcx>,
dst_ty: Ty<'tcx>
) -> (Bx::Value, Bx::Value) {
debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
match (&src_ty.sty, &dst_ty.sty) {
(&ty::Ref(_, a, _),
&ty::Ref(_, b, _)) |
(&ty::Ref(_, a, _),
&ty::RawPtr(ty::TypeAndMut { ty: b, .. })) |
(&ty::RawPtr(ty::TypeAndMut { ty: a, .. }),
&ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => {
assert!(bx.cx().type_is_sized(a));
let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
(bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
}
(&ty::Adt(def_a, _), &ty::Adt(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().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
(bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
}
(&ty::Adt(def_a, _), &ty::Adt(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, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)))
}
_ => 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: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
src: PlaceRef<'tcx, Bx::Value>,
dst: PlaceRef<'tcx, Bx::Value>
) {
let src_ty = src.layout.ty;
let dst_ty = dst.layout.ty;
let coerce_ptr = || {
let (base, info) = match bx.load_operand(src).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, bx.cx().backend_type(thin_ptr)), 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::Ref(..), &ty::Ref(..)) |
(&ty::Ref(..), &ty::RawPtr(..)) |
(&ty::RawPtr(..), &ty::RawPtr(..)) => {
coerce_ptr()
}
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
coerce_ptr()
}
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
assert_eq!(def_a, def_b);
for i in 0..def_a.variants[VariantIdx::new(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, dst_f.align, src_f.llval, src_f.align,
src_f.layout, 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<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
op: hir::BinOpKind,
lhs: Bx::Value,
rhs: Bx::Value
) -> Bx::Value {
cast_shift_rhs(bx, op, lhs, rhs, |a, b| bx.trunc(a, b), |a, b| bx.zext(a, b))
}
fn cast_shift_rhs<'a, 'tcx: 'a, F, G, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
op: hir::BinOpKind,
lhs: Bx::Value,
rhs: Bx::Value,
trunc: F,
zext: G
) -> Bx::Value
where F: FnOnce(
Bx::Value,
Bx::Type
) -> Bx::Value,
G: FnOnce(
Bx::Value,
Bx::Type
) -> Bx::Value
{
// Shifts may have any size int on the rhs
if op.is_shift() {
let mut rhs_llty = bx.cx().val_ty(rhs);
let mut lhs_llty = bx.cx().val_ty(lhs);
if bx.cx().type_kind(rhs_llty) == TypeKind::Vector {
rhs_llty = bx.cx().element_type(rhs_llty)
}
if bx.cx().type_kind(lhs_llty) == TypeKind::Vector {
lhs_llty = bx.cx().element_type(lhs_llty)
}
let rhs_sz = bx.cx().int_width(rhs_llty);
let lhs_sz = bx.cx().int_width(lhs_llty);
if lhs_sz < rhs_sz {
trunc(rhs, lhs_llty)
} else if lhs_sz > rhs_sz {
// FIXME (#1877: If in the future shifting by negative
// values is no longer 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: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
val: Bx::Value
) {
let assume_intrinsic = bx.cx().get_intrinsic("llvm.assume");
bx.call(assume_intrinsic, &[val], None);
}
pub fn from_immediate<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
val: Bx::Value
) -> Bx::Value {
if bx.cx().val_ty(val) == bx.cx().type_i1() {
bx.zext(val, bx.cx().type_i8())
} else {
val
}
}
pub fn to_immediate<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
val: Bx::Value,
layout: layout::TyLayout,
) -> Bx::Value {
if let layout::Abi::Scalar(ref scalar) = layout.abi {
return to_immediate_scalar(bx, val, scalar);
}
val
}
pub fn to_immediate_scalar<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
val: Bx::Value,
scalar: &layout::Scalar,
) -> Bx::Value {
if scalar.is_bool() {
return bx.trunc(val, bx.cx().type_i1());
}
val
}
pub fn memcpy_ty<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
bx: &Bx,
dst: Bx::Value,
dst_align: Align,
src: Bx::Value,
src_align: Align,
layout: TyLayout<'tcx>,
flags: MemFlags,
) {
let size = layout.size.bytes();
if size == 0 {
return;
}
bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags);
}
pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
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 sig = instance.fn_sig(cx.tcx());
let sig = cx.tcx().normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
let lldecl = cx.instances().borrow().get(&instance).cloned().unwrap_or_else(||
bug!("Instance `{:?}` not already declared", instance));
cx.stats().borrow_mut().n_closures += 1;
let mir = cx.tcx().instance_mir(instance.def);
mir::codegen_mir::<Bx>(cx, lldecl, &mir, instance, sig);
}
pub fn set_link_section(llval: &Value, attrs: &CodegenFnAttrs) {
let sect = match attrs.link_section {
Some(name) => name,
None => return,
};
unsafe {
let buf = SmallCStr::new(&sect.as_str());
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<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx
) {
let (main_def_id, span) = match *cx.sess().entry_fn.borrow() {
Some((id, span, _)) => {
(cx.tcx().hir.local_def_id(id), span)
}
None => return,
};
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 = cx.get_fn(instance);
let et = cx.sess().entry_fn.get().map(|e| e.2);
match et {
Some(EntryFnType::Main) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, true),
Some(EntryFnType::Start) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, false),
None => {} // Do nothing.
}
fn create_entry_fn<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
cx: &'a Bx::CodegenCx,
sp: Span,
rust_main: Bx::Value,
rust_main_def_id: DefId,
use_start_lang_item: bool,
) {
let llfty =
cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int());
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_bound_vars().unwrap(),
);
if cx.get_defined_value("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 = cx.declare_cfn("main", llfty);
// `main` should respect same config for frame pointer elimination as rest of code
cx.set_frame_pointer_elimination(llfn);
cx.apply_target_cpu_attr(llfn);
let bx = Bx::new_block(&cx, llfn, "top");
bx.insert_reference_to_gdb_debug_scripts_section_global();
// Params from native main() used as args for rust start function
let param_argc = cx.get_param(llfn, 0);
let param_argv = cx.get_param(llfn, 1);
let arg_argc = bx.intcast(param_argc, cx.type_isize(), 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, cx.type_ptr_to(cx.type_i8p())),
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, cx.type_int(), true));
}
}
pub(crate) fn write_metadata<'a, 'gcx>(
tcx: TyCtxt<'a, 'gcx, 'gcx>,
llvm_module: &ModuleLlvm
) -> EncodedMetadata {
use std::io::Write;
use flate2::Compression;
use flate2::write::DeflateEncoder;
let (metadata_llcx, metadata_llmod) = (&*llvm_module.llcx, llvm_module.llmod());
#[derive(PartialEq, Eq, PartialOrd, Ord)]
enum MetadataKind {
None,
Uncompressed,
Compressed
}
let kind = tcx.sess.crate_types.borrow().iter().map(|ty| {
match *ty {
config::CrateType::Executable |
config::CrateType::Staticlib |
config::CrateType::Cdylib => MetadataKind::None,
config::CrateType::Rlib => MetadataKind::Uncompressed,
config::CrateType::Dylib |
config::CrateType::ProcMacro => MetadataKind::Compressed,
}
}).max().unwrap_or(MetadataKind::None);
if kind == MetadataKind::None {
return EncodedMetadata::new();
}
let metadata = tcx.encode_metadata();
if kind == MetadataKind::Uncompressed {
return 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 = common::bytes_in_context(metadata_llcx, &compressed);
let llconst = common::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, common::val_ty(llconst), buf.as_ptr())
};
unsafe {
llvm::LLVMSetInitializer(llglobal, llconst);
let section_name = metadata::metadata_section_name(&tcx.sess.target.target);
let name = SmallCStr::new(section_name);
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;
}
pub struct ValueIter<'ll> {
cur: Option<&'ll Value>,
step: unsafe extern "C" fn(&'ll Value) -> Option<&'ll Value>,
}
impl Iterator for ValueIter<'ll> {
type Item = &'ll Value;
fn next(&mut self) -> Option<&'ll Value> {
let old = self.cur;
if let Some(old) = old {
self.cur = unsafe { (self.step)(old) };
}
old
}
}
pub fn iter_globals(llmod: &'ll llvm::Module) -> ValueIter<'ll> {
unsafe {
ValueIter {
cur: llvm::LLVMGetFirstGlobal(llmod),
step: llvm::LLVMGetNextGlobal,
}
}
}
fn determine_cgu_reuse<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
cgu: &CodegenUnit<'tcx>)
-> CguReuse {
if !tcx.dep_graph.is_fully_enabled() {
return CguReuse::No
}
let work_product_id = &cgu.work_product_id();
if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
// We don't have anything cached for this CGU. This can happen
// if the CGU did not exist in the previous session.
return CguReuse::No
}
// Try to mark the CGU as green. If it we can do so, it means that nothing
// affecting the LLVM module has changed and we can re-use a cached version.
// If we compile with any kind of LTO, this means we can re-use the bitcode
// of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
// know that later). If we are not doing LTO, there is only one optimized
// version of each module, so we re-use that.
let dep_node = cgu.codegen_dep_node(tcx);
assert!(!tcx.dep_graph.dep_node_exists(&dep_node),
"CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
cgu.name());
if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
// We can re-use either the pre- or the post-thinlto state
if tcx.sess.lto() != Lto::No {
CguReuse::PreLto
} else {
CguReuse::PostLto
}
} else {
CguReuse::No
}
}
pub fn codegen_crate<B: BackendMethods>(
backend: B,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
rx: mpsc::Receiver<Box<dyn Any + Send>>
) -> B::OngoingCodegen {
check_for_rustc_errors_attr(tcx);
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
// Codegen the metadata.
tcx.sess.profiler(|p| p.start_activity(ProfileCategory::Codegen));
let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
&["crate"],
Some("metadata")).as_str()
.to_string();
let metadata_llvm_module = backend.new_metadata(tcx.sess, &metadata_cgu_name);
let metadata = time(tcx.sess, "write metadata", || {
backend.write_metadata(tcx, &metadata_llvm_module)
});
tcx.sess.profiler(|p| p.end_activity(ProfileCategory::Codegen));
let metadata_module = ModuleCodegen {
name: metadata_cgu_name,
module_llvm: metadata_llvm_module,
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 = backend.start_async_codegen(
tcx,
time_graph,
metadata,
rx,
1);
backend.submit_pre_codegened_module_to_llvm(&ongoing_codegen, tcx, metadata_module);
backend.codegen_finished(&ongoing_codegen, tcx);
assert_and_save_dep_graph(tcx);
backend.check_for_errors(&ongoing_codegen, 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 = backend.start_async_codegen(
tcx,
time_graph.clone(),
metadata,
rx,
codegen_units.len());
let ongoing_codegen = AbortCodegenOnDrop::<B>(Some(ongoing_codegen));
// Codegen an allocator shim, if necessary.
//
// If the crate doesn't have an `allocator_kind` set then there's definitely
// no shim to generate. Otherwise we also check our dependency graph for all
// our output crate types. If anything there looks like its a `Dynamic`
// linkage, then it's already got an allocator shim and we'll be using that
// one instead. If nothing exists then it's our job to generate the
// allocator!
let any_dynamic_crate = tcx.sess.dependency_formats.borrow()
.iter()
.any(|(_, list)| {
use rustc::middle::dependency_format::Linkage;
list.iter().any(|&linkage| linkage == Linkage::Dynamic)
});
let allocator_module = if any_dynamic_crate {
None
} else if let Some(kind) = *tcx.sess.allocator_kind.get() {
let llmod_id = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
&["crate"],
Some("allocator")).as_str()
.to_string();
let modules = backend.new_metadata(tcx.sess, &llmod_id);
time(tcx.sess, "write allocator module", || {
backend.codegen_allocator(tcx, &modules, kind)
});
Some(ModuleCodegen {
name: llmod_id,
module_llvm: modules,
kind: ModuleKind::Allocator,
})
} else {
None
};
if let Some(allocator_module) = allocator_module {
backend.submit_pre_codegened_module_to_llvm(&ongoing_codegen, tcx, allocator_module);
}
backend.submit_pre_codegened_module_to_llvm(&ongoing_codegen, 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() {
backend.wait_for_signal_to_codegen_item(&ongoing_codegen);
backend.check_for_errors(&ongoing_codegen, tcx.sess);
let cgu_reuse = determine_cgu_reuse(tcx, &cgu);
tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
match cgu_reuse {
CguReuse::No => {
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();
let stats = backend.compile_codegen_unit(tcx, *cgu.name());
all_stats.extend(stats);
total_codegen_time += start_time.elapsed();
false
}
CguReuse::PreLto => {
write::submit_pre_lto_module_to_llvm(tcx, CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.work_product(tcx),
});
true
}
CguReuse::PostLto => {
write::submit_post_lto_module_to_llvm(tcx, CachedModuleCodegen {
name: cgu.name().to_string(),
source: cgu.work_product(tcx),
});
true
}
};
}
backend.codegen_finished(&ongoing_codegen, 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);
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);
}
}
backend.check_for_errors(&ongoing_codegen, tcx.sess);
assert_and_save_dep_graph(tcx);
ongoing_codegen.into_inner()
}
/// A curious wrapper structure whose only purpose is to call `codegen_aborted`
/// when it's dropped abnormally.
///
/// In the process of working on rust-lang/rust#55238 a mysterious segfault was
/// stumbled upon. The segfault was never reproduced locally, but it was
/// suspected to be related to the fact that codegen worker threads were
/// sticking around by the time the main thread was exiting, causing issues.
///
/// This structure is an attempt to fix that issue where the `codegen_aborted`
/// message will block until all workers have finished. This should ensure that
/// even if the main codegen thread panics we'll wait for pending work to
/// complete before returning from the main thread, hopefully avoiding
/// segfaults.
///
/// If you see this comment in the code, then it means that this workaround
/// worked! We may yet one day track down the mysterious cause of that
/// segfault...
struct AbortCodegenOnDrop<B: BackendMethods>(Option<B::OngoingCodegen>);
impl<B: BackendMethods> AbortCodegenOnDrop<B> {
fn into_inner(mut self) -> B::OngoingCodegen {
self.0.take().unwrap()
}
}
impl<B: BackendMethods> Deref for AbortCodegenOnDrop<B> {
type Target = B::OngoingCodegen;
fn deref(&self) -> &B::OngoingCodegen {
self.0.as_ref().unwrap()
}
}
impl<B: BackendMethods> DerefMut for AbortCodegenOnDrop<B> {
fn deref_mut(&mut self) -> &mut B::OngoingCodegen {
self.0.as_mut().unwrap()
}
}
impl<B: BackendMethods> Drop for AbortCodegenOnDrop<B> {
fn drop(&mut self) {
if let Some(codegen) = self.0.take() {
B::codegen_aborted(codegen);
}
}
}
fn assert_and_save_dep_graph<'ll, 'tcx>(tcx: TyCtxt<'ll, '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));
}
impl CrateInfo {
pub fn new(tcx: TyCtxt) -> CrateInfo {
let mut info = CrateInfo {
panic_runtime: None,
compiler_builtins: None,
profiler_runtime: None,
sanitizer_runtime: None,
is_no_builtins: Default::default(),
native_libraries: Default::default(),
used_libraries: tcx.native_libraries(LOCAL_CRATE),
link_args: tcx.link_args(LOCAL_CRATE),
crate_name: Default::default(),
used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic),
used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic),
used_crate_source: Default::default(),
wasm_imports: Default::default(),
lang_item_to_crate: Default::default(),
missing_lang_items: Default::default(),
};
let lang_items = tcx.lang_items();
let load_wasm_items = tcx.sess.crate_types.borrow()
.iter()
.any(|c| *c != config::CrateType::Rlib) &&
tcx.sess.opts.target_triple.triple() == "wasm32-unknown-unknown";
if load_wasm_items {
info.load_wasm_imports(tcx, LOCAL_CRATE);
}
let crates = tcx.crates();
let n_crates = crates.len();
info.native_libraries.reserve(n_crates);
info.crate_name.reserve(n_crates);
info.used_crate_source.reserve(n_crates);
info.missing_lang_items.reserve(n_crates);
for &cnum in crates.iter() {
info.native_libraries.insert(cnum, tcx.native_libraries(cnum));
info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum));
if tcx.is_panic_runtime(cnum) {
info.panic_runtime = Some(cnum);
}
if tcx.is_compiler_builtins(cnum) {
info.compiler_builtins = Some(cnum);
}
if tcx.is_profiler_runtime(cnum) {
info.profiler_runtime = Some(cnum);
}
if tcx.is_sanitizer_runtime(cnum) {
info.sanitizer_runtime = Some(cnum);
}
if tcx.is_no_builtins(cnum) {
info.is_no_builtins.insert(cnum);
}
if load_wasm_items {
info.load_wasm_imports(tcx, cnum);
}
let missing = tcx.missing_lang_items(cnum);
for &item in missing.iter() {
if let Ok(id) = lang_items.require(item) {
info.lang_item_to_crate.insert(item, id.krate);
}
}
// No need to look for lang items that are whitelisted and don't
// actually need to exist.
let missing = missing.iter()
.cloned()
.filter(|&l| !weak_lang_items::whitelisted(tcx, l))
.collect();
info.missing_lang_items.insert(cnum, missing);
}
return info
}
fn load_wasm_imports(&mut self, tcx: TyCtxt, cnum: CrateNum) {
self.wasm_imports.extend(tcx.wasm_import_module_map(cnum).iter().map(|(&id, module)| {
let instance = Instance::mono(tcx, id);
let import_name = tcx.symbol_name(instance);
(import_name.to_string(), module.clone())
}));
}
}
pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
cgu_name: InternedString)
-> Stats {
let start_time = Instant::now();
let dep_node = tcx.codegen_unit(cgu_name).codegen_dep_node(tcx);
let ((stats, module), _) = tcx.dep_graph.with_task(dep_node,
tcx,
cgu_name,
module_codegen);
let time_to_codegen = start_time.elapsed();
// We assume that the cost to run LLVM on a CGU is proportional to
// the time we needed for codegenning it.
let cost = time_to_codegen.as_secs() * 1_000_000_000 +
time_to_codegen.subsec_nanos() as u64;
write::submit_codegened_module_to_llvm(tcx,
module,
cost);
return stats;
fn module_codegen<'ll, 'tcx>(
tcx: TyCtxt<'ll, 'tcx, 'tcx>,
cgu_name: InternedString)
-> (Stats, ModuleCodegen<ModuleLlvm>)
{
let backend = LlvmCodegenBackend(());
let cgu = tcx.codegen_unit(cgu_name);
// Instantiate monomorphizations without filling out definitions yet...
let llvm_module = backend.new_metadata(tcx.sess, &cgu_name.as_str());
let stats = {
let cx = CodegenCx::new(tcx, cgu, &llvm_module);
let mono_items = cx.codegen_unit
.items_in_deterministic_order(cx.tcx);
for &(mono_item, (linkage, visibility)) in &mono_items {
mono_item.predefine::<Builder<&Value>>(&cx, linkage, visibility);
}
// ... and now that we have everything pre-defined, fill out those definitions.
for &(mono_item, _) in &mono_items {
mono_item.define::<Builder<&Value>>(&cx);
}
// If this codegen unit contains the main function, also create the
// wrapper here
maybe_create_entry_wrapper::<Builder<&Value>>(&cx);
// Run replace-all-uses-with for statics that need it
for &(old_g, new_g) in cx.statics_to_rauw().borrow().iter() {
cx.static_replace_all_uses(old_g, new_g)
}
// Create the llvm.used variable
// This variable has type [N x i8*] and is stored in the llvm.metadata section
if !cx.used_statics().borrow().is_empty() {
cx.create_used_variable()
}
// Finalize debuginfo
if cx.sess().opts.debuginfo != DebugInfo::None {
cx.debuginfo_finalize();
}
cx.consume_stats().into_inner()
};
(stats, ModuleCodegen {
name: cgu_name.to_string(),
module_llvm: llvm_module,
kind: ModuleKind::Regular,
})
}
}
pub fn provide_both(providers: &mut Providers) {
providers.dllimport_foreign_items = |tcx, krate| {
let module_map = tcx.foreign_modules(krate);
let module_map = module_map.iter()
.map(|lib| (lib.def_id, lib))
.collect::<FxHashMap<_, _>>();
let dllimports = tcx.native_libraries(krate)
.iter()
.filter(|lib| {
if lib.kind != cstore::NativeLibraryKind::NativeUnknown {
return false
}
let cfg = match lib.cfg {
Some(ref cfg) => cfg,
None => return true,
};
attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
})
.filter_map(|lib| lib.foreign_module)
.map(|id| &module_map[&id])
.flat_map(|module| module.foreign_items.iter().cloned())
.collect();
Lrc::new(dllimports)
};
providers.is_dllimport_foreign_item = |tcx, def_id| {
tcx.dllimport_foreign_items(def_id.krate).contains(&def_id)
};
}
pub fn linkage_to_llvm(linkage: Linkage) -> llvm::Linkage {
match linkage {
Linkage::External => llvm::Linkage::ExternalLinkage,
Linkage::AvailableExternally => llvm::Linkage::AvailableExternallyLinkage,
Linkage::LinkOnceAny => llvm::Linkage::LinkOnceAnyLinkage,
Linkage::LinkOnceODR => llvm::Linkage::LinkOnceODRLinkage,
Linkage::WeakAny => llvm::Linkage::WeakAnyLinkage,
Linkage::WeakODR => llvm::Linkage::WeakODRLinkage,
Linkage::Appending => llvm::Linkage::AppendingLinkage,
Linkage::Internal => llvm::Linkage::InternalLinkage,
Linkage::Private => llvm::Linkage::PrivateLinkage,
Linkage::ExternalWeak => llvm::Linkage::ExternalWeakLinkage,
Linkage::Common => llvm::Linkage::CommonLinkage,
}
}
pub fn visibility_to_llvm(linkage: Visibility) -> llvm::Visibility {
match linkage {
Visibility::Default => llvm::Visibility::Default,
Visibility::Hidden => llvm::Visibility::Hidden,
Visibility::Protected => llvm::Visibility::Protected,
}
}