464 lines
19 KiB
Rust
464 lines
19 KiB
Rust
use rustc::mir;
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use rustc::ty::layout::{self, LayoutOf, Size};
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use rustc::ty;
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use rustc::mir::interpret::{EvalResult, PointerArithmetic};
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use crate::{
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PlaceTy, OpTy, Immediate, Scalar, ScalarMaybeUndef, Borrow,
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ScalarExt, OperatorEvalContextExt
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};
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pub trait EvalContextExt<'tcx> {
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fn call_intrinsic(
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&mut self,
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instance: ty::Instance<'tcx>,
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args: &[OpTy<'tcx, Borrow>],
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dest: PlaceTy<'tcx, Borrow>,
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) -> EvalResult<'tcx>;
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}
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impl<'a, 'mir, 'tcx> EvalContextExt<'tcx> for super::MiriEvalContext<'a, 'mir, 'tcx> {
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fn call_intrinsic(
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&mut self,
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instance: ty::Instance<'tcx>,
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args: &[OpTy<'tcx, Borrow>],
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dest: PlaceTy<'tcx, Borrow>,
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) -> EvalResult<'tcx> {
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if self.emulate_intrinsic(instance, args, dest)? {
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return Ok(());
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}
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let tcx = &{self.tcx.tcx};
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let substs = instance.substs;
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// All these intrinsics take raw pointers, so if we access memory directly
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// (as opposed to through a place), we have to remember to erase any tag
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// that might still hang around!
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let intrinsic_name = &self.tcx.item_name(instance.def_id()).as_str()[..];
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match intrinsic_name {
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"arith_offset" => {
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let offset = self.read_scalar(args[1])?.to_isize(self)?;
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let ptr = self.read_scalar(args[0])?.not_undef()?;
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let pointee_ty = substs.type_at(0);
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let pointee_size = self.layout_of(pointee_ty)?.size.bytes() as i64;
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let offset = offset.overflowing_mul(pointee_size).0;
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let result_ptr = ptr.ptr_wrapping_signed_offset(offset, self);
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self.write_scalar(result_ptr, dest)?;
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}
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"assume" => {
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let cond = self.read_scalar(args[0])?.to_bool()?;
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if !cond {
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return err!(AssumptionNotHeld);
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}
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}
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"atomic_load" |
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"atomic_load_relaxed" |
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"atomic_load_acq" |
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"volatile_load" => {
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let ptr = self.deref_operand(args[0])?;
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let val = self.read_scalar(ptr.into())?; // make sure it fits into a scalar; otherwise it cannot be atomic
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self.write_scalar(val, dest)?;
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}
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"atomic_store" |
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"atomic_store_relaxed" |
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"atomic_store_rel" |
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"volatile_store" => {
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let ptr = self.deref_operand(args[0])?;
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let val = self.read_scalar(args[1])?; // make sure it fits into a scalar; otherwise it cannot be atomic
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self.write_scalar(val, ptr.into())?;
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}
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"atomic_fence_acq" => {
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// we are inherently singlethreaded and singlecored, this is a nop
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}
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_ if intrinsic_name.starts_with("atomic_xchg") => {
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let ptr = self.deref_operand(args[0])?;
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let new = self.read_scalar(args[1])?;
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let old = self.read_scalar(ptr.into())?;
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self.write_scalar(old, dest)?; // old value is returned
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self.write_scalar(new, ptr.into())?;
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}
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_ if intrinsic_name.starts_with("atomic_cxchg") => {
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let ptr = self.deref_operand(args[0])?;
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let expect_old = self.read_immediate(args[1])?; // read as immediate for the sake of `binary_op_imm()`
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let new = self.read_scalar(args[2])?;
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let old = self.read_immediate(ptr.into())?; // read as immediate for the sake of `binary_op_imm()`
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// binary_op_imm will bail if either of them is not a scalar
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let (eq, _) = self.binary_op_imm(mir::BinOp::Eq, old, expect_old)?;
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let res = Immediate::ScalarPair(old.to_scalar_or_undef(), eq.into());
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self.write_immediate(res, dest)?; // old value is returned
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// update ptr depending on comparison
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if eq.to_bool()? {
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self.write_scalar(new, ptr.into())?;
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}
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}
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"atomic_or" |
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"atomic_or_acq" |
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"atomic_or_rel" |
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"atomic_or_acqrel" |
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"atomic_or_relaxed" |
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"atomic_xor" |
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"atomic_xor_acq" |
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"atomic_xor_rel" |
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"atomic_xor_acqrel" |
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"atomic_xor_relaxed" |
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"atomic_and" |
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"atomic_and_acq" |
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"atomic_and_rel" |
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"atomic_and_acqrel" |
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"atomic_and_relaxed" |
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"atomic_xadd" |
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"atomic_xadd_acq" |
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"atomic_xadd_rel" |
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"atomic_xadd_acqrel" |
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"atomic_xadd_relaxed" |
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"atomic_xsub" |
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"atomic_xsub_acq" |
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"atomic_xsub_rel" |
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"atomic_xsub_acqrel" |
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"atomic_xsub_relaxed" => {
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let ptr = self.deref_operand(args[0])?;
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if !ptr.layout.ty.is_integral() {
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return err!(Unimplemented(format!("Atomic arithmetic operations only work on integer types")));
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}
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let rhs = self.read_immediate(args[1])?;
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let old = self.read_immediate(ptr.into())?;
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self.write_immediate(*old, dest)?; // old value is returned
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let op = match intrinsic_name.split('_').nth(1).unwrap() {
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"or" => mir::BinOp::BitOr,
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"xor" => mir::BinOp::BitXor,
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"and" => mir::BinOp::BitAnd,
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"xadd" => mir::BinOp::Add,
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"xsub" => mir::BinOp::Sub,
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_ => bug!(),
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};
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// Atomics wrap around on overflow.
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self.binop_ignore_overflow(op, old, rhs, ptr.into())?;
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}
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"breakpoint" => unimplemented!(), // halt miri
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"copy" |
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"copy_nonoverlapping" => {
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let elem_ty = substs.type_at(0);
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let elem_layout = self.layout_of(elem_ty)?;
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let elem_size = elem_layout.size.bytes();
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let count = self.read_scalar(args[2])?.to_usize(self)?;
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let elem_align = elem_layout.align.abi;
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// erase tags: this is a raw ptr operation
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let src = self.read_scalar(args[0])?.not_undef()?;
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let dest = self.read_scalar(args[1])?.not_undef()?;
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self.memory_mut().copy(
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src,
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elem_align,
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dest,
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elem_align,
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Size::from_bytes(count * elem_size),
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intrinsic_name.ends_with("_nonoverlapping"),
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)?;
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}
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"discriminant_value" => {
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let place = self.deref_operand(args[0])?;
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let discr_val = self.read_discriminant(place.into())?.0;
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self.write_scalar(Scalar::from_uint(discr_val, dest.layout.size), dest)?;
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}
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"sinf32" | "fabsf32" | "cosf32" | "sqrtf32" | "expf32" | "exp2f32" | "logf32" |
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"log10f32" | "log2f32" | "floorf32" | "ceilf32" | "truncf32" => {
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let f = self.read_scalar(args[0])?.to_f32()?;
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let f = match intrinsic_name {
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"sinf32" => f.sin(),
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"fabsf32" => f.abs(),
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"cosf32" => f.cos(),
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"sqrtf32" => f.sqrt(),
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"expf32" => f.exp(),
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"exp2f32" => f.exp2(),
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"logf32" => f.ln(),
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"log10f32" => f.log10(),
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"log2f32" => f.log2(),
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"floorf32" => f.floor(),
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"ceilf32" => f.ceil(),
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"truncf32" => f.trunc(),
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_ => bug!(),
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};
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self.write_scalar(Scalar::from_f32(f), dest)?;
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}
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"sinf64" | "fabsf64" | "cosf64" | "sqrtf64" | "expf64" | "exp2f64" | "logf64" |
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"log10f64" | "log2f64" | "floorf64" | "ceilf64" | "truncf64" => {
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let f = self.read_scalar(args[0])?.to_f64()?;
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let f = match intrinsic_name {
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"sinf64" => f.sin(),
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"fabsf64" => f.abs(),
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"cosf64" => f.cos(),
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"sqrtf64" => f.sqrt(),
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"expf64" => f.exp(),
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"exp2f64" => f.exp2(),
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"logf64" => f.ln(),
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"log10f64" => f.log10(),
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"log2f64" => f.log2(),
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"floorf64" => f.floor(),
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"ceilf64" => f.ceil(),
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"truncf64" => f.trunc(),
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_ => bug!(),
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};
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self.write_scalar(Scalar::from_f64(f), dest)?;
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}
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"fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
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let a = self.read_immediate(args[0])?;
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let b = self.read_immediate(args[1])?;
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let op = match intrinsic_name {
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"fadd_fast" => mir::BinOp::Add,
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"fsub_fast" => mir::BinOp::Sub,
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"fmul_fast" => mir::BinOp::Mul,
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"fdiv_fast" => mir::BinOp::Div,
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"frem_fast" => mir::BinOp::Rem,
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_ => bug!(),
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};
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self.binop_ignore_overflow(op, a, b, dest)?;
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}
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"exact_div" => {
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// Performs an exact division, resulting in undefined behavior where
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// `x % y != 0` or `y == 0` or `x == T::min_value() && y == -1`
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let a = self.read_immediate(args[0])?;
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let b = self.read_immediate(args[1])?;
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// check x % y != 0
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if self.binary_op_imm(mir::BinOp::Rem, a, b)?.0.to_bytes()? != 0 {
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return err!(ValidationFailure(format!("exact_div: {:?} cannot be divided by {:?}", a, b)));
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}
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self.binop_ignore_overflow(mir::BinOp::Div, a, b, dest)?;
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},
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"likely" | "unlikely" | "forget" => {}
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"init" => {
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// Check fast path: we don't want to force an allocation in case the destination is a simple value,
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// but we also do not want to create a new allocation with 0s and then copy that over.
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// FIXME: We do not properly validate in case of ZSTs and when doing it in memory!
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// However, this only affects direct calls of the intrinsic; calls to the stable
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// functions wrapping them do get their validation.
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// FIXME: should we check that the destination pointer is aligned even for ZSTs?
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if !dest.layout.is_zst() { // nothing to do for ZST
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match dest.layout.abi {
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layout::Abi::Scalar(ref s) => {
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let x = Scalar::from_int(0, s.value.size(self));
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self.write_immediate(Immediate::Scalar(x.into()), dest)?;
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}
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layout::Abi::ScalarPair(ref s1, ref s2) => {
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let x = Scalar::from_int(0, s1.value.size(self));
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let y = Scalar::from_int(0, s2.value.size(self));
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self.write_immediate(Immediate::ScalarPair(x.into(), y.into()), dest)?;
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}
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_ => {
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// Do it in memory
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let mplace = self.force_allocation(dest)?;
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assert!(mplace.meta.is_none());
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// not a zst, must be valid pointer
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let ptr = mplace.ptr.to_ptr()?;
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self.memory_mut().get_mut(ptr.alloc_id)?.write_repeat(tcx, ptr, 0, dest.layout.size)?;
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}
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}
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}
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}
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"pref_align_of" => {
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let ty = substs.type_at(0);
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let layout = self.layout_of(ty)?;
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let align = layout.align.pref.bytes();
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let ptr_size = self.pointer_size();
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let align_val = Scalar::from_uint(align as u128, ptr_size);
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self.write_scalar(align_val, dest)?;
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}
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"move_val_init" => {
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let ptr = self.deref_operand(args[0])?;
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self.copy_op(args[1], ptr.into())?;
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}
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"offset" => {
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let offset = self.read_scalar(args[1])?.to_isize(self)?;
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let ptr = self.read_scalar(args[0])?.not_undef()?;
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let result_ptr = self.pointer_offset_inbounds(ptr, substs.type_at(0), offset)?;
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self.write_scalar(result_ptr, dest)?;
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}
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"powf32" => {
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let f = self.read_scalar(args[0])?.to_f32()?;
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let f2 = self.read_scalar(args[1])?.to_f32()?;
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self.write_scalar(
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Scalar::from_f32(f.powf(f2)),
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dest,
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)?;
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}
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"powf64" => {
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let f = self.read_scalar(args[0])?.to_f64()?;
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let f2 = self.read_scalar(args[1])?.to_f64()?;
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self.write_scalar(
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Scalar::from_f64(f.powf(f2)),
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dest,
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)?;
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}
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"fmaf32" => {
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let a = self.read_scalar(args[0])?.to_f32()?;
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let b = self.read_scalar(args[1])?.to_f32()?;
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let c = self.read_scalar(args[2])?.to_f32()?;
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self.write_scalar(
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Scalar::from_f32(a * b + c),
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dest,
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)?;
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}
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"fmaf64" => {
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let a = self.read_scalar(args[0])?.to_f64()?;
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let b = self.read_scalar(args[1])?.to_f64()?;
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let c = self.read_scalar(args[2])?.to_f64()?;
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self.write_scalar(
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Scalar::from_f64(a * b + c),
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dest,
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)?;
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}
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"powif32" => {
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let f = self.read_scalar(args[0])?.to_f32()?;
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let i = self.read_scalar(args[1])?.to_i32()?;
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self.write_scalar(
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Scalar::from_f32(f.powi(i)),
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dest,
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)?;
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}
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"powif64" => {
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let f = self.read_scalar(args[0])?.to_f64()?;
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let i = self.read_scalar(args[1])?.to_i32()?;
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self.write_scalar(
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Scalar::from_f64(f.powi(i)),
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dest,
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)?;
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}
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"size_of_val" => {
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let mplace = self.deref_operand(args[0])?;
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let (size, _) = self.size_and_align_of_mplace(mplace)?
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.expect("size_of_val called on extern type");
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let ptr_size = self.pointer_size();
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self.write_scalar(
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Scalar::from_uint(size.bytes() as u128, ptr_size),
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dest,
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)?;
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}
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"min_align_of_val" |
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"align_of_val" => {
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let mplace = self.deref_operand(args[0])?;
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let (_, align) = self.size_and_align_of_mplace(mplace)?
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.expect("size_of_val called on extern type");
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let ptr_size = self.pointer_size();
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self.write_scalar(
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Scalar::from_uint(align.bytes(), ptr_size),
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dest,
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)?;
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}
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"type_name" => {
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let ty = substs.type_at(0);
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let ty_name = ty.to_string();
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let value = self.str_to_immediate(&ty_name)?;
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self.write_immediate(value, dest)?;
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}
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"unchecked_div" => {
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let l = self.read_immediate(args[0])?;
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let r = self.read_immediate(args[1])?;
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let rval = r.to_scalar()?.to_bytes()?;
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if rval == 0 {
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return err!(Intrinsic(format!("Division by 0 in unchecked_div")));
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}
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self.binop_ignore_overflow(
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mir::BinOp::Div,
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l,
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r,
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dest,
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)?;
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}
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"unchecked_rem" => {
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let l = self.read_immediate(args[0])?;
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let r = self.read_immediate(args[1])?;
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let rval = r.to_scalar()?.to_bytes()?;
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if rval == 0 {
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return err!(Intrinsic(format!("Division by 0 in unchecked_rem")));
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}
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self.binop_ignore_overflow(
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mir::BinOp::Rem,
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l,
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r,
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dest,
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)?;
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}
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"uninit" => {
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// Check fast path: we don't want to force an allocation in case the destination is a simple value,
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// but we also do not want to create a new allocation with 0s and then copy that over.
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|
// FIXME: We do not properly validate in case of ZSTs and when doing it in memory!
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// However, this only affects direct calls of the intrinsic; calls to the stable
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// functions wrapping them do get their validation.
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// FIXME: should we check alignment for ZSTs?
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if !dest.layout.is_zst() { // nothing to do for ZST
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match dest.layout.abi {
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layout::Abi::Scalar(..) => {
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let x = ScalarMaybeUndef::Undef;
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self.write_immediate(Immediate::Scalar(x), dest)?;
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}
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layout::Abi::ScalarPair(..) => {
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let x = ScalarMaybeUndef::Undef;
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self.write_immediate(Immediate::ScalarPair(x, x), dest)?;
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}
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_ => {
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// Do it in memory
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let mplace = self.force_allocation(dest)?;
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assert!(mplace.meta.is_none());
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let ptr = mplace.ptr.to_ptr()?;
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self.memory_mut()
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.get_mut(ptr.alloc_id)?
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.mark_definedness(ptr, dest.layout.size, false)?;
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}
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}
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}
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}
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"write_bytes" => {
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let ty = substs.type_at(0);
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let ty_layout = self.layout_of(ty)?;
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let val_byte = self.read_scalar(args[1])?.to_u8()?;
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let ptr = self.read_scalar(args[0])?.not_undef()?;
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let count = self.read_scalar(args[2])?.to_usize(self)?;
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|
self.memory().check_align(ptr, ty_layout.align.abi)?;
|
|
let byte_count = ty_layout.size * count;
|
|
if byte_count.bytes() != 0 {
|
|
let ptr = ptr.to_ptr()?;
|
|
self.memory_mut()
|
|
.get_mut(ptr.alloc_id)?
|
|
.write_repeat(tcx, ptr, val_byte, byte_count)?;
|
|
}
|
|
}
|
|
|
|
name => return err!(Unimplemented(format!("unimplemented intrinsic: {}", name))),
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
}
|