don't always allocate for the uninit
intrinsic
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parent
92f6874ead
commit
a9b984d21e
2 changed files with 27 additions and 15 deletions
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@ -1555,7 +1555,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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/// convenience function to ensure correct usage of globals and code-sharing with locals
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pub fn modify_global<
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F: FnOnce(&mut Self, Option<Value>) -> EvalResult<'tcx, Value>,
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F: FnOnce(&mut Self, Option<Value>) -> EvalResult<'tcx, Option<Value>>,
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>(
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&mut self,
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cid: GlobalId<'tcx>,
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@ -1565,14 +1565,14 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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if !val.mutable {
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return Err(EvalError::ModifiedConstantMemory);
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}
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val.data = Some(f(self, val.data)?);
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val.data = f(self, val.data)?;
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*self.globals.get_mut(&cid).expect("already checked") = val;
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Ok(())
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}
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/// convenience function to ensure correct usage of locals and code-sharing with globals
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pub fn modify_local<
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F: FnOnce(&mut Self, Option<Value>) -> EvalResult<'tcx, Value>,
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F: FnOnce(&mut Self, Option<Value>) -> EvalResult<'tcx, Option<Value>>,
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>(
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&mut self,
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frame: usize,
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@ -1581,7 +1581,8 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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) -> EvalResult<'tcx, ()> {
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let val = self.stack[frame].get_local(local);
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let val = f(self, val)?;
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self.stack[frame].set_local(local, val);
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// can't use `set_local` here, because that's only meant for going to an initialized value
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self.stack[frame].locals[local.index() - 1] = val;
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Ok(())
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}
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}
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@ -131,21 +131,21 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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match val {
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Some(Value::ByRef(ptr)) => {
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this.memory.write_repeat(ptr, 0, size)?;
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Ok(Value::ByRef(ptr))
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Ok(Some(Value::ByRef(ptr)))
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},
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None => match this.ty_to_primval_kind(dest_ty) {
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Ok(kind) => Ok(Value::ByVal(PrimVal::new(0, kind))),
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Ok(kind) => Ok(Some(Value::ByVal(PrimVal::new(0, kind)))),
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Err(_) => {
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let ptr = this.alloc_ptr_with_substs(dest_ty, substs)?;
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this.memory.write_repeat(ptr, 0, size)?;
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Ok(Value::ByRef(ptr))
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Ok(Some(Value::ByRef(ptr)))
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}
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},
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Some(Value::ByVal(value)) => Ok(Value::ByVal(PrimVal::new(0, value.kind))),
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Some(Value::ByValPair(a, b)) => Ok(Value::ByValPair(
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Some(Value::ByVal(value)) => Ok(Some(Value::ByVal(PrimVal::new(0, value.kind)))),
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Some(Value::ByValPair(a, b)) => Ok(Some(Value::ByValPair(
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PrimVal::new(0, a.kind),
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PrimVal::new(0, b.kind),
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)),
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))),
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}
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};
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match dest {
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@ -271,12 +271,23 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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}
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"uninit" => {
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// FIXME(solson): Attempt writing a None over the destination when it's an
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// Lvalue::Local (that is not ByRef). Otherwise do the mark_definedness as usual.
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let dest = self.force_allocation(dest)?.to_ptr();
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let size = dest_layout.size(&self.tcx.data_layout).bytes() as usize;
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self.memory.mark_definedness(dest, size, false)?;
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let uninit = |this: &mut Self, val: Option<Value>| {
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match val {
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Some(Value::ByRef(ptr)) => {
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this.memory.mark_definedness(ptr, size, false)?;
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Ok(Some(Value::ByRef(ptr)))
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},
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None => Ok(None),
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Some(_) => Ok(None),
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}
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};
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match dest {
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Lvalue::Local { frame, local } => self.modify_local(frame, local, uninit)?,
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Lvalue::Ptr { ptr, extra: LvalueExtra::None } => self.memory.mark_definedness(ptr, size, false)?,
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Lvalue::Ptr { .. } => bug!("uninit intrinsic tried to write to fat ptr target"),
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Lvalue::Global(cid) => self.modify_global(cid, uninit)?,
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}
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}
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name => return Err(EvalError::Unimplemented(format!("unimplemented intrinsic: {}", name))),
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