- adds handling of zero-sized types for volatile_store.
- adds type size checks and warnigns for other volatile intrinsics.
- adds a test to check warnings emitting.
Cause of the issue
While preparing for trans_intrinsic_call() invoke arguments are
processed with trans_argument() method which excludes zero-sized types
from argument list (to be more correct - all arguments for which
ArgKind is Ignore are filtered out). As result volatile_store() intrinsic
gets one argument instead of expected address and value.
How it is fixed
Modification of the trans_argument() method may cause side effects,
therefore change was implemented in volatile_store() intrinsic building
code itself. Now it checks function signature and if it was specialised
with zero-sized type, then emits C_nil() instead of accessing
non-existing second argument.
Additionally warnings are added for all volatile operations which are
specialised with zero-sized arguments. In fact, those operations are omitted
in LLVM backend if no memory affected at all, e.g. number of elements
is zero or type is zero-sized. This was not explicitly documented before
and could lead to potential issues if developer expects volatile behaviour,
but type has degraded to zero-sized.
Some(ccx.get_intrinsic(&llvm_name))
}
+fn warn_if_size_is_weird<'a, 'tcx>(bcx: &Builder<'a, 'tcx>,
+ tp_ty: Ty<'tcx>,
+ count: ValueRef,
+ span: Span,
+ name: &str) {
+ let ccx = bcx.ccx;
+ let lltp_ty = type_of::type_of(ccx, tp_ty);
+ let ty_size = machine::llsize_of(ccx, lltp_ty);
+ let total = const_to_uint( bcx.mul(ty_size, count) );
+
+ if total > 0 {
+ return;
+ }
+
+ let text = format!("suspicious monomorphization of `{}` intrinsic", name);
+ let note = match name
+ {
+ "volatile_load" | "volatile_store" =>
+ format!("'{}' was specialized with zero-sized type '{}'",
+ name, tp_ty),
+ _ => format!("'{}' was specialized with type '{}', number of \
+ elements is {}",
+ name, tp_ty,
+ const_to_uint(count))
+ };
+
+ let sess = bcx.sess();
+ sess.struct_span_warn(span, &text)
+ .note(¬e)
+ .emit();
+}
+
/// Remember to add all intrinsics here, in librustc_typeck/check/mod.rs,
/// and in libcore/intrinsics.rs; if you need access to any llvm intrinsics,
/// add them to librustc_trans/trans/context.rs
}
"volatile_copy_nonoverlapping_memory" => {
- copy_intrinsic(bcx, false, true, substs.type_at(0), llargs[0], llargs[1], llargs[2])
+ let tp_ty = substs.type_at(0);
+ warn_if_size_is_weird(bcx, tp_ty, llargs[2], span, name);
+ copy_intrinsic(bcx, false, true, tp_ty, llargs[0], llargs[1], llargs[2])
}
"volatile_copy_memory" => {
- copy_intrinsic(bcx, true, true, substs.type_at(0), llargs[0], llargs[1], llargs[2])
+ let tp_ty = substs.type_at(0);
+ warn_if_size_is_weird(bcx, tp_ty, llargs[2], span, name);
+ copy_intrinsic(bcx, true, true, tp_ty, llargs[0], llargs[1], llargs[2])
}
"volatile_set_memory" => {
- memset_intrinsic(bcx, true, substs.type_at(0), llargs[0], llargs[1], llargs[2])
+ let tp_ty = substs.type_at(0);
+ warn_if_size_is_weird(bcx, tp_ty, llargs[2], span, name);
+ memset_intrinsic(bcx, true, tp_ty, llargs[0], llargs[1], llargs[2])
}
"volatile_load" => {
let tp_ty = substs.type_at(0);
let mut ptr = llargs[0];
+ warn_if_size_is_weird(bcx, tp_ty, C_uint(ccx,1usize), span, name);
if let Some(ty) = fn_ty.ret.cast {
ptr = bcx.pointercast(ptr, ty.ptr_to());
}
},
"volatile_store" => {
let tp_ty = substs.type_at(0);
+ warn_if_size_is_weird(bcx, tp_ty, C_uint(ccx,1usize), span, name);
if type_is_fat_ptr(bcx.ccx, tp_ty) {
bcx.volatile_store(llargs[1], get_dataptr(bcx, llargs[0]));
bcx.volatile_store(llargs[2], get_meta(bcx, llargs[0]));
let val = if fn_ty.args[1].is_indirect() {
bcx.load(llargs[1], None)
} else {
- from_immediate(bcx, llargs[1])
+ if !type_is_zero_size(ccx, tp_ty) {
+ from_immediate(bcx, llargs[1])
+ } else {
+ C_nil(ccx)
+ }
};
let ptr = bcx.pointercast(llargs[0], val_ty(val).ptr_to());
let store = bcx.volatile_store(val, ptr);
--- /dev/null
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+#![feature(core_intrinsics)]
+
+use std::intrinsics::{ volatile_copy_memory, volatile_store, volatile_load,
+ volatile_copy_nonoverlapping_memory,
+ volatile_set_memory };
+
+fn main () {
+ let mut dst_pair = (1, 2);
+ let src_pair = (3, 4);
+ let mut dst_empty = ();
+ let src_empty = ();
+
+ const COUNT_0: usize = 0;
+ const COUNT_100: usize = 100;
+
+ unsafe {
+ volatile_copy_memory(&mut dst_pair, &dst_pair, COUNT_0);
+ volatile_copy_nonoverlapping_memory(&mut dst_pair, &src_pair, 0);
+ volatile_copy_memory(&mut dst_empty, &dst_empty, 100);
+ volatile_copy_nonoverlapping_memory(&mut dst_empty, &src_empty,
+ COUNT_100);
+ volatile_set_memory(&mut dst_empty, 0, COUNT_100);
+ volatile_set_memory(&mut dst_pair, 0, COUNT_0);
+ volatile_store(&mut dst_empty, ());
+ volatile_store(&mut dst_empty, src_empty);
+ volatile_load(&src_empty);
+ }
+}
--- /dev/null
+warning: suspicious monomorphization of `volatile_copy_memory` intrinsic
+ --> $DIR/issue-39827.rs:26:9
+ |
+26 | volatile_copy_memory(&mut dst_pair, &dst_pair, COUNT_0);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_copy_memory' was specialized with type '(i32, i32)', number of elements is 0
+
+warning: suspicious monomorphization of `volatile_copy_nonoverlapping_memory` intrinsic
+ --> $DIR/issue-39827.rs:27:9
+ |
+27 | volatile_copy_nonoverlapping_memory(&mut dst_pair, &src_pair, 0);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_copy_nonoverlapping_memory' was specialized with type '(i32, i32)', number of elements is 0
+
+warning: suspicious monomorphization of `volatile_copy_memory` intrinsic
+ --> $DIR/issue-39827.rs:28:9
+ |
+28 | volatile_copy_memory(&mut dst_empty, &dst_empty, 100);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_copy_memory' was specialized with type '()', number of elements is 100
+
+warning: suspicious monomorphization of `volatile_copy_nonoverlapping_memory` intrinsic
+ --> $DIR/issue-39827.rs:29:9
+ |
+29 | / volatile_copy_nonoverlapping_memory(&mut dst_empty, &src_empty,
+30 | | COUNT_100);
+ | |______________________________________________________^
+ |
+ = note: 'volatile_copy_nonoverlapping_memory' was specialized with type '()', number of elements is 100
+
+warning: suspicious monomorphization of `volatile_set_memory` intrinsic
+ --> $DIR/issue-39827.rs:31:9
+ |
+31 | volatile_set_memory(&mut dst_empty, 0, COUNT_100);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_set_memory' was specialized with type '()', number of elements is 100
+
+warning: suspicious monomorphization of `volatile_set_memory` intrinsic
+ --> $DIR/issue-39827.rs:32:9
+ |
+32 | volatile_set_memory(&mut dst_pair, 0, COUNT_0);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_set_memory' was specialized with type '(i32, i32)', number of elements is 0
+
+warning: suspicious monomorphization of `volatile_store` intrinsic
+ --> $DIR/issue-39827.rs:33:9
+ |
+33 | volatile_store(&mut dst_empty, ());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_store' was specialized with zero-sized type '()'
+
+warning: suspicious monomorphization of `volatile_store` intrinsic
+ --> $DIR/issue-39827.rs:34:9
+ |
+34 | volatile_store(&mut dst_empty, src_empty);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_store' was specialized with zero-sized type '()'
+
+warning: suspicious monomorphization of `volatile_load` intrinsic
+ --> $DIR/issue-39827.rs:35:9
+ |
+35 | volatile_load(&src_empty);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: 'volatile_load' was specialized with zero-sized type '()'
+
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