+//! Handling of `static`s, `const`s and promoted allocations
+
use rustc_span::DUMMY_SP;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_errors::ErrorReported;
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir::interpret::{
- read_target_uint, AllocId, Allocation, ConstValue, GlobalAlloc, Pointer, Scalar,
+ read_target_uint, AllocId, Allocation, ConstValue, ErrorHandled, GlobalAlloc, Pointer, Scalar,
};
-use rustc_middle::ty::{Const, ConstKind};
-use rustc_target::abi::Align;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_middle::ty::ConstKind;
use cranelift_codegen::ir::GlobalValueData;
use cranelift_module::*;
use crate::prelude::*;
-#[derive(Default)]
pub(crate) struct ConstantCx {
todo: Vec<TodoItem>,
done: FxHashSet<DataId>,
+ anon_allocs: FxHashMap<AllocId, DataId>,
}
#[derive(Copy, Clone, Debug)]
}
impl ConstantCx {
- pub(crate) fn finalize(mut self, tcx: TyCtxt<'_>, module: &mut Module<impl Backend>) {
+ pub(crate) fn new() -> Self {
+ ConstantCx { todo: vec![], done: FxHashSet::default(), anon_allocs: FxHashMap::default() }
+ }
+
+ pub(crate) fn finalize(mut self, tcx: TyCtxt<'_>, module: &mut dyn Module) {
//println!("todo {:?}", self.todo);
define_all_allocs(tcx, module, &mut self);
//println!("done {:?}", self.done);
}
}
-pub(crate) fn codegen_static(constants_cx: &mut ConstantCx, def_id: DefId) {
+pub(crate) fn check_constants(fx: &mut FunctionCx<'_, '_, '_>) -> bool {
+ let mut all_constants_ok = true;
+ for constant in &fx.mir.required_consts {
+ let const_ = match fx.monomorphize(constant.literal) {
+ ConstantKind::Ty(ct) => ct,
+ ConstantKind::Val(..) => continue,
+ };
+ match const_.val {
+ ConstKind::Value(_) => {}
+ ConstKind::Unevaluated(unevaluated) => {
+ if let Err(err) =
+ fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None)
+ {
+ all_constants_ok = false;
+ match err {
+ ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {
+ fx.tcx.sess.span_err(constant.span, "erroneous constant encountered");
+ }
+ ErrorHandled::TooGeneric => {
+ span_bug!(
+ constant.span,
+ "codgen encountered polymorphic constant: {:?}",
+ err
+ );
+ }
+ }
+ }
+ }
+ ConstKind::Param(_)
+ | ConstKind::Infer(_)
+ | ConstKind::Bound(_, _)
+ | ConstKind::Placeholder(_)
+ | ConstKind::Error(_) => unreachable!("{:?}", const_),
+ }
+ }
+ all_constants_ok
+}
+
+pub(crate) fn codegen_static(tcx: TyCtxt<'_>, module: &mut dyn Module, def_id: DefId) {
+ let mut constants_cx = ConstantCx::new();
constants_cx.todo.push(TodoItem::Static(def_id));
+ constants_cx.finalize(tcx, module);
}
pub(crate) fn codegen_tls_ref<'tcx>(
- fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+ fx: &mut FunctionCx<'_, '_, 'tcx>,
def_id: DefId,
layout: TyAndLayout<'tcx>,
) -> CValue<'tcx> {
- let linkage = crate::linkage::get_static_ref_linkage(fx.tcx, def_id);
- let data_id = data_id_for_static(fx.tcx, fx.module, def_id, linkage);
+ let data_id = data_id_for_static(fx.tcx, fx.module, def_id, false);
let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
- #[cfg(debug_assertions)]
- fx.add_comment(local_data_id, format!("tls {:?}", def_id));
+ if fx.clif_comments.enabled() {
+ fx.add_comment(local_data_id, format!("tls {:?}", def_id));
+ }
let tls_ptr = fx.bcx.ins().tls_value(fx.pointer_type, local_data_id);
CValue::by_val(tls_ptr, layout)
}
fn codegen_static_ref<'tcx>(
- fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+ fx: &mut FunctionCx<'_, '_, 'tcx>,
def_id: DefId,
layout: TyAndLayout<'tcx>,
) -> CPlace<'tcx> {
- let linkage = crate::linkage::get_static_ref_linkage(fx.tcx, def_id);
- let data_id = data_id_for_static(fx.tcx, fx.module, def_id, linkage);
+ let data_id = data_id_for_static(fx.tcx, fx.module, def_id, false);
let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
- #[cfg(debug_assertions)]
- fx.add_comment(local_data_id, format!("{:?}", def_id));
+ if fx.clif_comments.enabled() {
+ fx.add_comment(local_data_id, format!("{:?}", def_id));
+ }
let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
assert!(!layout.is_unsized(), "unsized statics aren't supported");
- assert!(matches!(fx.bcx.func.global_values[local_data_id], GlobalValueData::Symbol { tls: false, ..}), "tls static referenced without Rvalue::ThreadLocalRef");
+ assert!(
+ matches!(
+ fx.bcx.func.global_values[local_data_id],
+ GlobalValueData::Symbol { tls: false, .. }
+ ),
+ "tls static referenced without Rvalue::ThreadLocalRef"
+ );
CPlace::for_ptr(crate::pointer::Pointer::new(global_ptr), layout)
}
-pub(crate) fn trans_constant<'tcx>(
- fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+pub(crate) fn codegen_constant<'tcx>(
+ fx: &mut FunctionCx<'_, '_, 'tcx>,
constant: &Constant<'tcx>,
) -> CValue<'tcx> {
- let const_ = match constant.literal.val {
- ConstKind::Unevaluated(def_id, ref substs, promoted) if fx.tcx.is_static(def_id) => {
+ let const_ = match fx.monomorphize(constant.literal) {
+ ConstantKind::Ty(ct) => ct,
+ ConstantKind::Val(val, ty) => return codegen_const_value(fx, val, ty),
+ };
+ let const_val = match const_.val {
+ ConstKind::Value(const_val) => const_val,
+ ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
+ if fx.tcx.is_static(def.did) =>
+ {
assert!(substs.is_empty());
assert!(promoted.is_none());
- return codegen_static_ref(
- fx,
- def_id,
- fx.layout_of(fx.monomorphize(&constant.literal.ty)),
- ).to_cvalue(fx);
+ return codegen_static_ref(fx, def.did, fx.layout_of(const_.ty)).to_cvalue(fx);
}
- _ => fx.monomorphize(&constant.literal).eval(fx.tcx, ParamEnv::reveal_all()),
+ ConstKind::Unevaluated(unevaluated) => {
+ match fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None) {
+ Ok(const_val) => const_val,
+ Err(_) => {
+ span_bug!(constant.span, "erroneous constant not captured by required_consts");
+ }
+ }
+ }
+ ConstKind::Param(_)
+ | ConstKind::Infer(_)
+ | ConstKind::Bound(_, _)
+ | ConstKind::Placeholder(_)
+ | ConstKind::Error(_) => unreachable!("{:?}", const_),
};
- trans_const_value(fx, const_)
+ codegen_const_value(fx, const_val, const_.ty)
}
-pub(crate) fn trans_const_value<'tcx>(
- fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
- const_: &'tcx Const<'tcx>,
+pub(crate) fn codegen_const_value<'tcx>(
+ fx: &mut FunctionCx<'_, '_, 'tcx>,
+ const_val: ConstValue<'tcx>,
+ ty: Ty<'tcx>,
) -> CValue<'tcx> {
- let ty = fx.monomorphize(&const_.ty);
let layout = fx.layout_of(ty);
assert!(!layout.is_unsized(), "sized const value");
if layout.is_zst() {
- return CValue::by_ref(
- crate::Pointer::const_addr(fx, i64::try_from(layout.align.pref.bytes()).unwrap()),
- layout,
- );
+ return CValue::by_ref(crate::Pointer::dangling(layout.align.pref), layout);
}
- let const_val = match const_.val {
- ConstKind::Value(const_val) => const_val,
- _ => unreachable!("Const {:?} should have been evaluated", const_),
- };
match const_val {
ConstValue::Scalar(x) => {
}
match x {
- Scalar::Raw { data, size } => {
- assert_eq!(u64::from(size), layout.size.bytes());
- return CValue::const_val(fx, layout, data);
- }
+ Scalar::Int(int) => CValue::const_val(fx, layout, int),
Scalar::Ptr(ptr) => {
let alloc_kind = fx.tcx.get_global_alloc(ptr.alloc_id);
let base_addr = match alloc_kind {
Some(GlobalAlloc::Memory(alloc)) => {
fx.constants_cx.todo.push(TodoItem::Alloc(ptr.alloc_id));
- let data_id = data_id_for_alloc_id(fx.module, ptr.alloc_id, alloc.align);
- let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
- #[cfg(debug_assertions)]
- fx.add_comment(local_data_id, format!("{:?}", ptr.alloc_id));
+ let data_id = data_id_for_alloc_id(
+ &mut fx.constants_cx,
+ fx.module,
+ ptr.alloc_id,
+ alloc.mutability,
+ );
+ let local_data_id =
+ fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+ if fx.clif_comments.enabled() {
+ fx.add_comment(local_data_id, format!("{:?}", ptr.alloc_id));
+ }
fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
}
Some(GlobalAlloc::Function(instance)) => {
let func_id = crate::abi::import_function(fx.tcx, fx.module, instance);
- let local_func_id = fx.module.declare_func_in_func(func_id, &mut fx.bcx.func);
+ let local_func_id =
+ fx.module.declare_func_in_func(func_id, &mut fx.bcx.func);
fx.bcx.ins().func_addr(fx.pointer_type, local_func_id)
}
Some(GlobalAlloc::Static(def_id)) => {
assert!(fx.tcx.is_static(def_id));
- let linkage = crate::linkage::get_static_ref_linkage(fx.tcx, def_id);
- let data_id = data_id_for_static(fx.tcx, fx.module, def_id, linkage);
- let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
- #[cfg(debug_assertions)]
- fx.add_comment(local_data_id, format!("{:?}", def_id));
+ let data_id = data_id_for_static(fx.tcx, fx.module, def_id, false);
+ let local_data_id =
+ fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
+ if fx.clif_comments.enabled() {
+ fx.add_comment(local_data_id, format!("{:?}", def_id));
+ }
fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
}
None => bug!("missing allocation {:?}", ptr.alloc_id),
};
- let val = fx.bcx.ins().iadd_imm(base_addr, i64::try_from(ptr.offset.bytes()).unwrap());
- return CValue::by_val(val, layout);
+ let val = if ptr.offset.bytes() != 0 {
+ fx.bcx.ins().iadd_imm(base_addr, i64::try_from(ptr.offset.bytes()).unwrap())
+ } else {
+ base_addr
+ };
+ CValue::by_val(val, layout)
}
}
}
- ConstValue::ByRef { alloc, offset } => {
- CValue::by_ref(
- pointer_for_allocation(fx, alloc)
- .offset_i64(fx, i64::try_from(offset.bytes()).unwrap()),
- layout,
- )
- }
+ ConstValue::ByRef { alloc, offset } => CValue::by_ref(
+ pointer_for_allocation(fx, alloc)
+ .offset_i64(fx, i64::try_from(offset.bytes()).unwrap()),
+ layout,
+ ),
ConstValue::Slice { data, start, end } => {
let ptr = pointer_for_allocation(fx, data)
.offset_i64(fx, i64::try_from(start).unwrap())
.get_addr(fx);
- let len = fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(end.checked_sub(start).unwrap()).unwrap());
+ let len = fx
+ .bcx
+ .ins()
+ .iconst(fx.pointer_type, i64::try_from(end.checked_sub(start).unwrap()).unwrap());
CValue::by_val_pair(ptr, len, layout)
}
}
}
fn pointer_for_allocation<'tcx>(
- fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
+ fx: &mut FunctionCx<'_, '_, 'tcx>,
alloc: &'tcx Allocation,
) -> crate::pointer::Pointer {
let alloc_id = fx.tcx.create_memory_alloc(alloc);
fx.constants_cx.todo.push(TodoItem::Alloc(alloc_id));
- let data_id = data_id_for_alloc_id(fx.module, alloc_id, alloc.align);
+ let data_id =
+ data_id_for_alloc_id(&mut fx.constants_cx, &mut *fx.module, alloc_id, alloc.mutability);
let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
- #[cfg(debug_assertions)]
- fx.add_comment(local_data_id, format!("{:?}", alloc_id));
+ if fx.clif_comments.enabled() {
+ fx.add_comment(local_data_id, format!("{:?}", alloc_id));
+ }
let global_ptr = fx.bcx.ins().global_value(fx.pointer_type, local_data_id);
crate::pointer::Pointer::new(global_ptr)
}
-fn data_id_for_alloc_id<B: Backend>(
- module: &mut Module<B>,
+fn data_id_for_alloc_id(
+ cx: &mut ConstantCx,
+ module: &mut dyn Module,
alloc_id: AllocId,
- align: Align,
+ mutability: rustc_hir::Mutability,
) -> DataId {
- module
- .declare_data(
- &format!("__alloc_{}", alloc_id.0),
- Linkage::Local,
- false,
- false,
- Some(align.bytes() as u8),
- )
- .unwrap()
+ *cx.anon_allocs.entry(alloc_id).or_insert_with(|| {
+ module.declare_anonymous_data(mutability == rustc_hir::Mutability::Mut, false).unwrap()
+ })
}
fn data_id_for_static(
tcx: TyCtxt<'_>,
- module: &mut Module<impl Backend>,
+ module: &mut dyn Module,
def_id: DefId,
- linkage: Linkage,
+ definition: bool,
) -> DataId {
- let instance = Instance::mono(tcx, def_id);
- let symbol_name = tcx.symbol_name(instance).name.as_str();
- let ty = instance.monomorphic_ty(tcx);
+ let rlinkage = tcx.codegen_fn_attrs(def_id).linkage;
+ let linkage = if definition {
+ crate::linkage::get_static_linkage(tcx, def_id)
+ } else if rlinkage == Some(rustc_middle::mir::mono::Linkage::ExternalWeak)
+ || rlinkage == Some(rustc_middle::mir::mono::Linkage::WeakAny)
+ {
+ Linkage::Preemptible
+ } else {
+ Linkage::Import
+ };
+
+ let instance = Instance::mono(tcx, def_id).polymorphize(tcx);
+ let symbol_name = tcx.symbol_name(instance).name;
+ let ty = instance.ty(tcx, ParamEnv::reveal_all());
let is_mutable = if tcx.is_mutable_static(def_id) {
true
} else {
!ty.is_freeze(tcx.at(DUMMY_SP), ParamEnv::reveal_all())
};
- let align = tcx
- .layout_of(ParamEnv::reveal_all().and(ty))
- .unwrap()
- .align
- .pref
- .bytes();
+ let align = tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap().align.pref.bytes();
let attrs = tcx.codegen_fn_attrs(def_id);
linkage,
is_mutable,
attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL),
- Some(align.try_into().unwrap()),
)
.unwrap();
- if linkage == Linkage::Preemptible {
- if let ty::RawPtr(_) = ty.kind {
- } else {
- tcx.sess.span_fatal(
- tcx.def_span(def_id),
- "must have type `*const T` or `*mut T` due to `#[linkage]` attribute",
- )
- }
-
+ if rlinkage.is_some() {
+ // Comment copied from https://github.com/rust-lang/rust/blob/45060c2a66dfd667f88bd8b94261b28a58d85bd5/src/librustc_codegen_llvm/consts.rs#L141
+ // Declare an internal global `extern_with_linkage_foo` which
+ // is initialized with the address of `foo`. If `foo` is
+ // discarded during linking (for example, if `foo` has weak
+ // linkage and there are no definitions), then
+ // `extern_with_linkage_foo` will instead be initialized to
+ // zero.
+
+ let ref_name = format!("_rust_extern_with_linkage_{}", symbol_name);
+ let ref_data_id = module.declare_data(&ref_name, Linkage::Local, false, false).unwrap();
let mut data_ctx = DataContext::new();
- data_ctx.define_zeroinit(pointer_ty(tcx).bytes() as usize);
- match module.define_data(data_id, &data_ctx) {
- // Everytime a weak static is referenced, there will be a zero pointer definition,
+ data_ctx.set_align(align);
+ let data = module.declare_data_in_data(data_id, &mut data_ctx);
+ data_ctx.define(std::iter::repeat(0).take(pointer_ty(tcx).bytes() as usize).collect());
+ data_ctx.write_data_addr(0, data, 0);
+ match module.define_data(ref_data_id, &data_ctx) {
+ // Every time the static is referenced there will be another definition of this global,
// so duplicate definitions are expected and allowed.
Err(ModuleError::DuplicateDefinition(_)) => {}
res => res.unwrap(),
}
+ ref_data_id
+ } else {
+ data_id
}
-
- data_id
}
-fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut Module<impl Backend>, cx: &mut ConstantCx) {
+fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut ConstantCx) {
while let Some(todo_item) = cx.todo.pop() {
let (data_id, alloc, section_name) = match todo_item {
TodoItem::Alloc(alloc_id) => {
GlobalAlloc::Memory(alloc) => alloc,
GlobalAlloc::Function(_) | GlobalAlloc::Static(_) => unreachable!(),
};
- let data_id = data_id_for_alloc_id(module, alloc_id, alloc.align);
+ let data_id = data_id_for_alloc_id(cx, module, alloc_id, alloc.mutability);
(data_id, alloc, None)
}
TodoItem::Static(def_id) => {
let section_name = tcx.codegen_fn_attrs(def_id).link_section.map(|s| s.as_str());
- let const_ = tcx.const_eval_poly(def_id).unwrap();
-
- let alloc = match const_ {
- ConstValue::ByRef { alloc, offset } if offset.bytes() == 0 => alloc,
- _ => bug!("static const eval returned {:#?}", const_),
- };
+ let alloc = tcx.eval_static_initializer(def_id).unwrap();
- let data_id = data_id_for_static(
- tcx,
- module,
- def_id,
- if tcx.is_reachable_non_generic(def_id) {
- Linkage::Export
- } else {
- Linkage::Export // FIXME Set hidden visibility
- },
- );
+ let data_id = data_id_for_static(tcx, module, def_id, true);
(data_id, alloc, section_name)
}
};
}
let mut data_ctx = DataContext::new();
+ data_ctx.set_align(alloc.align.bytes());
if let Some(section_name) = section_name {
// FIXME set correct segment for Mach-O files
data_ctx.set_segment_section("", &*section_name);
}
- let bytes = alloc.inspect_with_undef_and_ptr_outside_interpreter(0..alloc.len()).to_vec();
+ let bytes = alloc.inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()).to_vec();
data_ctx.define(bytes.into_boxed_slice());
for &(offset, (_tag, reloc)) in alloc.relocations().iter() {
let endianness = tcx.data_layout.endian;
let offset = offset.bytes() as usize;
let ptr_size = tcx.data_layout.pointer_size;
- let bytes = &alloc.inspect_with_undef_and_ptr_outside_interpreter(offset..offset + ptr_size.bytes() as usize);
+ let bytes = &alloc.inspect_with_uninit_and_ptr_outside_interpreter(
+ offset..offset + ptr_size.bytes() as usize,
+ );
read_target_uint(endianness, bytes).unwrap()
};
data_ctx.write_function_addr(offset.bytes() as u32, local_func_id);
continue;
}
- GlobalAlloc::Memory(_) => {
+ GlobalAlloc::Memory(target_alloc) => {
cx.todo.push(TodoItem::Alloc(reloc));
- data_id_for_alloc_id(module, reloc, alloc.align)
+ data_id_for_alloc_id(cx, module, reloc, target_alloc.mutability)
}
GlobalAlloc::Static(def_id) => {
- if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) {
- tcx.sess.fatal(&format!("Allocation {:?} contains reference to TLS value {:?}", alloc, def_id));
+ if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::THREAD_LOCAL)
+ {
+ tcx.sess.fatal(&format!(
+ "Allocation {:?} contains reference to TLS value {:?}",
+ alloc, def_id
+ ));
}
// Don't push a `TodoItem::Static` here, as it will cause statics used by
// multiple crates to be duplicated between them. It isn't necessary anyway,
// as it will get pushed by `codegen_static` when necessary.
- data_id_for_static(
- tcx,
- module,
- def_id,
- crate::linkage::get_static_ref_linkage(tcx, def_id),
- )
+ data_id_for_static(tcx, module, def_id, false)
}
};
}
pub(crate) fn mir_operand_get_const_val<'tcx>(
- fx: &FunctionCx<'_, 'tcx, impl Backend>,
+ fx: &FunctionCx<'_, '_, 'tcx>,
operand: &Operand<'tcx>,
-) -> Option<&'tcx Const<'tcx>> {
+) -> Option<ConstValue<'tcx>> {
match operand {
Operand::Copy(_) | Operand::Move(_) => None,
- Operand::Constant(const_) => {
- Some(fx.monomorphize(&const_.literal).eval(fx.tcx, ParamEnv::reveal_all()))
- }
+ Operand::Constant(const_) => match const_.literal {
+ ConstantKind::Ty(const_) => {
+ fx.monomorphize(const_).eval(fx.tcx, ParamEnv::reveal_all()).val.try_to_value()
+ }
+ ConstantKind::Val(val, _) => Some(val),
+ },
}
}
projects / rust.git / blobdiff