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CTFE engine: rename copy → copy_intrinsic, move to intrinsics.rs #84905

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May 7, 2021
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CTFE engine: rename copy → copy_intrinsic, move to intrinsics.rs #84905

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34 changes: 33 additions & 1 deletion compiler/rustc_mir/src/interpret/intrinsics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -323,7 +323,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
self.write_scalar(result, dest)?;
}
sym::copy => {
self.copy(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
self.copy_intrinsic(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
}
sym::offset => {
let ptr = self.read_scalar(&args[0])?.check_init()?;
Expand Down Expand Up @@ -530,4 +530,36 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
)?;
Ok(offset_ptr)
}

/// Copy `count*size_of::<T>()` many bytes from `*src` to `*dst`.
pub(crate) fn copy_intrinsic(
&mut self,
src: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
dst: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
count: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
nonoverlapping: bool,
) -> InterpResult<'tcx> {
let count = self.read_scalar(&count)?.to_machine_usize(self)?;
let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap().ty)?;
let (size, align) = (layout.size, layout.align.abi);
let size = size.checked_mul(count, self).ok_or_else(|| {
err_ub_format!(
"overflow computing total size of `{}`",
if nonoverlapping { "copy_nonoverlapping" } else { "copy" }
)
})?;

// Make sure we check both pointers for an access of the total size and aligment,
// *even if* the total size is 0.
let src =
self.memory.check_ptr_access(self.read_scalar(&src)?.check_init()?, size, align)?;

let dst =
self.memory.check_ptr_access(self.read_scalar(&dst)?.check_init()?, size, align)?;

if let (Some(src), Some(dst)) = (src, dst) {
self.memory.copy(src, dst, size, nonoverlapping)?;
}
Ok(())
}
}
34 changes: 1 addition & 33 deletions compiler/rustc_mir/src/interpret/step.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
//!
//! The main entry point is the `step` method.

use crate::interpret::OpTy;
use rustc_middle::mir;
use rustc_middle::mir::interpret::{InterpResult, Scalar};
use rustc_target::abi::LayoutOf;
Expand Down Expand Up @@ -119,7 +118,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let src = self.eval_operand(src, None)?;
let dst = self.eval_operand(dst, None)?;
let count = self.eval_operand(count, None)?;
self.copy(&src, &dst, &count, /* nonoverlapping */ true)?;
self.copy_intrinsic(&src, &dst, &count, /* nonoverlapping */ true)?;
}

// Statements we do not track.
Expand Down Expand Up @@ -149,37 +148,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Ok(())
}

pub(crate) fn copy(
&mut self,
src: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
dst: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
count: &OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
nonoverlapping: bool,
) -> InterpResult<'tcx> {
let count = self.read_scalar(&count)?.to_machine_usize(self)?;
let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap().ty)?;
let (size, align) = (layout.size, layout.align.abi);
let size = size.checked_mul(count, self).ok_or_else(|| {
err_ub_format!(
"overflow computing total size of `{}`",
if nonoverlapping { "copy_nonoverlapping" } else { "copy" }
)
})?;

// Make sure we check both pointers for an access of the total size and aligment,
// *even if* the total size is 0.
let src =
self.memory.check_ptr_access(self.read_scalar(&src)?.check_init()?, size, align)?;

let dst =
self.memory.check_ptr_access(self.read_scalar(&dst)?.check_init()?, size, align)?;

if let (Some(src), Some(dst)) = (src, dst) {
self.memory.copy(src, dst, size, nonoverlapping)?;
}
Ok(())
}

/// Evaluate an assignment statement.
///
/// There is no separate `eval_rvalue` function. Instead, the code for handling each rvalue
Expand Down