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Change GetSystemInfo to explicit offset.

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Mateusz Gienieczko 2022-05-21 19:44:12 +02:00
parent c4ee368acb
commit 63e98aee0c
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1 changed files with 22 additions and 13 deletions
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35
src/shims/windows/foreign_items.rs
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@ -111,6 +111,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
// Querying system information
"GetSystemInfo" => {
use crate::rustc_middle::ty::{layout::LayoutOf, TyKind, UintTy};
let [system_info] =
this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
let system_info = this.deref_operand(system_info)?;
@ -119,21 +121,28 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
system_info.ptr,
iter::repeat(0u8).take(system_info.layout.size.bytes() as usize),
)?;
let dword_size = Size::from_bytes(4);
// In WinApi SYSTEM_INFO's first field is a 4-byte union, but num_cpus
// inlines it as two 2-byte fields. In num_cpus case all fields are offset by 1
// compared to WinApi. See https://github.com/rust-lang/miri/issues/2136#issuecomment-1133661262.
let first_field = this.mplace_field(&system_info, 0)?;
let offset = if first_field.layout.size.bytes() == 2 { 1 } else { 0 };
let page_size = this.mplace_field(&system_info, 1 + offset)?;
let num_cpus = this.mplace_field(&system_info, 5 + offset)?;
// Set selected fields.
let dword_ty = this.tcx.mk_ty(TyKind::Uint(UintTy::U32));
let dword_layout = this.layout_of(dword_ty)?;
// Set page size.
this.write_scalar(Scalar::from_int(PAGE_SIZE, dword_size), &page_size.into())?;
let page_size = system_info.offset(
Size::from_bytes(4),
MemPlaceMeta::None,
dword_layout,
&this.tcx,
)?;
this.write_scalar(
Scalar::from_int(PAGE_SIZE, dword_layout.size),
&page_size.into(),
)?;
// Set number of processors.
this.write_scalar(Scalar::from_int(NUM_CPUS, dword_size), &num_cpus.into())?;
let num_cpus = system_info.offset(
Size::from_bytes(32),
MemPlaceMeta::None,
dword_layout,
&this.tcx,
)?;
this.write_scalar(Scalar::from_int(NUM_CPUS, dword_layout.size), &num_cpus.into())?;
}
// Thread-local storage