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move environ init to update_environ

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This commit is contained in:
Ralf Jung 2020-03-08 17:18:53 +01:00
parent 689600fa4a
commit 87dbf10e84
1 changed files with 12 additions and 12 deletions
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24
src/shims/env.rs
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@ -30,11 +30,6 @@ pub(crate) fn init<'mir, 'tcx>(
}
}
}
// Initialize the `environ` static
let layout = ecx.layout_of(ecx.tcx.types.usize)?;
let place = ecx.allocate(layout, MiriMemoryKind::Machine.into());
ecx.write_scalar(Scalar::from_machine_usize(0, &*ecx.tcx), place.into())?;
ecx.memory.extra.environ = Some(place);
ecx.update_environ()
}
}
@ -160,17 +155,22 @@ fn chdir(&mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
}
}
/// Updates the `environ` static. It should not be called before
/// `EnvVars::init`.
/// Updates the `environ` static.
/// The first time it gets called, also initializes `extra.environ`.
fn update_environ(&mut self) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
// Deallocate the old environ value.
let old_vars_ptr = this.read_scalar(this.memory.extra.environ.unwrap().into())?.not_undef()?;
// The pointer itself can be null because `EnvVars::init` only
// initializes the place for the static but not the static itself.
if !this.is_null(old_vars_ptr)? {
// Deallocate the old environ value, if any.
if let Some(environ) = this.memory.extra.environ {
let old_vars_ptr = this.read_scalar(environ.into())?.not_undef()?;
this.memory.deallocate(this.force_ptr(old_vars_ptr)?, None, MiriMemoryKind::Machine.into())?;
} else {
// No `environ` allocated yet, let's do that.
let layout = this.layout_of(this.tcx.types.usize)?;
let place = this.allocate(layout, MiriMemoryKind::Machine.into());
this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
this.memory.extra.environ = Some(place);
}
// Collect all the pointers to each variable in a vector.
let mut vars: Vec<Scalar<Tag>> = this.machine.env_vars.map.values().map(|&ptr| ptr.into()).collect();
// Add the trailing null pointer.