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Add a function to TyCtxt for computing an Allocation for a static item's initializer #75394

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Aug 12, 2020
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23 changes: 23 additions & 0 deletions src/librustc_middle/mir/interpret/queries.rs
Original file line number Diff line number Diff line change
Expand Up @@ -74,4 +74,27 @@ impl<'tcx> TyCtxt<'tcx> {
self.const_eval_validated(inputs)
}
}

/// Evaluate a static's initializer, returning the allocation of the initializer's memory.
pub fn eval_static_initializer(
self,
def_id: DefId,
) -> Result<&'tcx mir::Allocation, ErrorHandled> {
trace!("eval_static_initializer: Need to compute {:?}", def_id);
assert!(self.is_static(def_id));
let instance = ty::Instance::mono(self, def_id);
let gid = GlobalId { instance, promoted: None };
self.eval_to_allocation(gid, ty::ParamEnv::reveal_all())
}

/// Evaluate anything constant-like, returning the allocation of the final memory.
fn eval_to_allocation(
self,
gid: GlobalId<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) -> Result<&'tcx mir::Allocation, ErrorHandled> {
trace!("eval_to_allocation: Need to compute {:?}", gid);
let raw_const = self.const_eval_raw(param_env.and(gid))?;
Ok(self.global_alloc(raw_const.alloc_id).unwrap_memory())
}
}
20 changes: 4 additions & 16 deletions src/librustc_mir/interpret/memory.rs
Original file line number Diff line number Diff line change
Expand Up @@ -14,13 +14,12 @@ use std::ptr;

use rustc_ast::ast::Mutability;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_hir::def_id::DefId;
use rustc_middle::ty::{self, Instance, ParamEnv, TyCtxt};
use rustc_middle::ty::{Instance, ParamEnv, TyCtxt};
use rustc_target::abi::{Align, HasDataLayout, Size, TargetDataLayout};

use super::{
AllocId, AllocMap, Allocation, AllocationExtra, CheckInAllocMsg, GlobalAlloc, GlobalId,
InterpResult, Machine, MayLeak, Pointer, PointerArithmetic, Scalar,
AllocId, AllocMap, Allocation, AllocationExtra, CheckInAllocMsg, GlobalAlloc, InterpResult,
Machine, MayLeak, Pointer, PointerArithmetic, Scalar,
};
use crate::util::pretty;

Expand Down Expand Up @@ -119,17 +118,6 @@ pub struct Memory<'mir, 'tcx, M: Machine<'mir, 'tcx>> {
pub tcx: TyCtxt<'tcx>,
}

/// Return the `tcx` allocation containing the initial value of the given static
pub fn get_static(tcx: TyCtxt<'tcx>, def_id: DefId) -> InterpResult<'tcx, &'tcx Allocation> {
trace!("get_static: Need to compute {:?}", def_id);
let instance = Instance::mono(tcx, def_id);
let gid = GlobalId { instance, promoted: None };
// Use the raw query here to break validation cycles. Later uses of the static
// will call the full query anyway.
let raw_const = tcx.const_eval_raw(ty::ParamEnv::reveal_all().and(gid))?;
Ok(tcx.global_alloc(raw_const.alloc_id).unwrap_memory())
}

impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> HasDataLayout for Memory<'mir, 'tcx, M> {
#[inline]
fn data_layout(&self) -> &TargetDataLayout {
Expand Down Expand Up @@ -489,7 +477,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
throw_unsup!(ReadExternStatic(def_id));
}

(get_static(tcx, def_id)?, Some(def_id))
(tcx.eval_static_initializer(def_id)?, Some(def_id))
}
};
M::before_access_global(memory_extra, id, alloc, def_id, is_write)?;
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_mir/interpret/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ pub use rustc_middle::mir::interpret::*; // have all the `interpret` symbols in
pub use self::eval_context::{Frame, FrameInfo, InterpCx, LocalState, LocalValue, StackPopCleanup};
pub use self::intern::{intern_const_alloc_recursive, InternKind};
pub use self::machine::{compile_time_machine, AllocMap, Machine, MayLeak, StackPopJump};
pub use self::memory::{get_static, AllocCheck, FnVal, Memory, MemoryKind};
pub use self::memory::{AllocCheck, FnVal, Memory, MemoryKind};
pub use self::operand::{ImmTy, Immediate, OpTy, Operand};
pub use self::place::{MPlaceTy, MemPlace, MemPlaceMeta, Place, PlaceTy};
pub use self::validity::RefTracking;
Expand Down