mirror of https://github.com/rust-lang/rust
79611d90b6
Added "copy" to Debug fmt for copy operands
In MIR's debug mode (--emit mir) the printing for Operands is slightly inconsistent.
The RValues - values on the right side of an Assign - are usually printed with their Operand when they are Places.
Example:
_2 = move _3
But for arguments, the operand is omitted.
_2 = _1
I propose a change be made, to display the place with the operand.
_2 = copy _1
Move and copy have different semantics, meaning this difference is important and helpful to the user. It also adds consistency to the pretty printing.
-- EDIT --
Consider this example Rust program and its MIR output with the **updated pretty printer.**
This was generated with the arguments --emit mir --crate-type lib -Zmir-opt-level=0 (Otherwise, it's optimised away since it's a junk program).
```rust
fn main(foo: i32) {
let v = 10;
if v == 20 {
foo;
}
else {
v;
}
}
```
```MIR
// WARNING: This output format is intended for human consumers only
// and is subject to change without notice. Knock yourself out.
fn main(_1: i32) -> () {
debug foo => _1;
let mut _0: ();
let _2: i32;
let mut _3: bool;
let mut _4: i32;
let _5: i32;
let _6: i32;
scope 1 {
debug v => _2;
}
bb0: {
StorageLive(_2);
_2 = const 10_i32;
StorageLive(_3);
StorageLive(_4);
_4 = copy _2;
_3 = Eq(move _4, const 20_i32);
switchInt(move _3) -> [0: bb2, otherwise: bb1];
}
bb1: {
StorageDead(_4);
StorageLive(_5);
_5 = copy _1;
StorageDead(_5);
_0 = const ();
goto -> bb3;
}
bb2: {
StorageDead(_4);
StorageLive(_6);
_6 = copy _2;
StorageDead(_6);
_0 = const ();
goto -> bb3;
}
bb3: {
StorageDead(_3);
StorageDead(_2);
return;
}
}
```
In this example program, we can see that when we move a place, it is preceded by "move". e.g. ``` _3 = Eq(move _4, const 20_i32);```. However, when we copy a place such as ```_5 = _1;```, it is not preceded by the operand in the original printout. I propose to change the print to include the copy ```_5 = copy _1``` as in this example.
Regarding the arguments part. When I originally submitted this PR, I was under the impression this only affected the print for arguments to a function, but actually, it affects anything that uses a copy. This is preferable anyway with regard to consistency. The PR is about making ```copy``` explicit.
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| .. | ||
| address_of_pair.fn0.GVN.diff | ||
| address_of_pair.rs | ||
| aggregate.foo.GVN.panic-abort.diff | ||
| aggregate.foo.GVN.panic-unwind.diff | ||
| aggregate.main.GVN.panic-abort.diff | ||
| aggregate.main.GVN.panic-unwind.diff | ||
| aggregate.rs | ||
| array_index.main.GVN.32bit.panic-abort.diff | ||
| array_index.main.GVN.32bit.panic-unwind.diff | ||
| array_index.main.GVN.64bit.panic-abort.diff | ||
| array_index.main.GVN.64bit.panic-unwind.diff | ||
| array_index.rs | ||
| bad_op_div_by_zero.main.GVN.panic-abort.diff | ||
| bad_op_div_by_zero.main.GVN.panic-unwind.diff | ||
| bad_op_div_by_zero.rs | ||
| bad_op_mod_by_zero.main.GVN.panic-abort.diff | ||
| bad_op_mod_by_zero.main.GVN.panic-unwind.diff | ||
| bad_op_mod_by_zero.rs | ||
| bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-abort.diff | ||
| bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-unwind.diff | ||
| bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-abort.diff | ||
| bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-unwind.diff | ||
| bad_op_unsafe_oob_for_slices.rs | ||
| boolean_identities.rs | ||
| boolean_identities.test.GVN.diff | ||
| boxes.main.GVN.panic-abort.diff | ||
| boxes.main.GVN.panic-unwind.diff | ||
| boxes.rs | ||
| cast.main.GVN.diff | ||
| cast.rs | ||
| checked_add.main.GVN.panic-abort.diff | ||
| checked_add.main.GVN.panic-unwind.diff | ||
| checked_add.rs | ||
| control_flow_simplification.hello.GVN.panic-abort.diff | ||
| control_flow_simplification.hello.GVN.panic-unwind.diff | ||
| control_flow_simplification.hello.PreCodegen.before.panic-abort.mir | ||
| control_flow_simplification.hello.PreCodegen.before.panic-unwind.mir | ||
| control_flow_simplification.rs | ||
| discriminant.main.GVN.32bit.diff | ||
| discriminant.main.GVN.64bit.diff | ||
| discriminant.rs | ||
| indirect.main.GVN.panic-abort.diff | ||
| indirect.main.GVN.panic-unwind.diff | ||
| indirect.rs | ||
| indirect_mutation.bar.GVN.diff | ||
| indirect_mutation.foo.GVN.diff | ||
| indirect_mutation.rs | ||
| inherit_overflow.main.GVN.panic-abort.diff | ||
| inherit_overflow.main.GVN.panic-unwind.diff | ||
| inherit_overflow.rs | ||
| invalid_constant.main.GVN.diff | ||
| invalid_constant.main.RemoveZsts.diff | ||
| invalid_constant.rs | ||
| issue_66971.main.GVN.panic-abort.diff | ||
| issue_66971.main.GVN.panic-unwind.diff | ||
| issue_66971.rs | ||
| issue_67019.main.GVN.panic-abort.diff | ||
| issue_67019.main.GVN.panic-unwind.diff | ||
| issue_67019.rs | ||
| large_array_index.main.GVN.32bit.panic-abort.diff | ||
| large_array_index.main.GVN.32bit.panic-unwind.diff | ||
| large_array_index.main.GVN.64bit.panic-abort.diff | ||
| large_array_index.main.GVN.64bit.panic-unwind.diff | ||
| large_array_index.rs | ||
| mult_by_zero.rs | ||
| mult_by_zero.test.GVN.diff | ||
| mutable_variable.main.GVN.diff | ||
| mutable_variable.rs | ||
| mutable_variable_aggregate.main.GVN.diff | ||
| mutable_variable_aggregate.rs | ||
| mutable_variable_aggregate_mut_ref.main.GVN.diff | ||
| mutable_variable_aggregate_mut_ref.rs | ||
| mutable_variable_aggregate_partial_read.main.GVN.panic-abort.diff | ||
| mutable_variable_aggregate_partial_read.main.GVN.panic-unwind.diff | ||
| mutable_variable_aggregate_partial_read.rs | ||
| mutable_variable_no_prop.main.GVN.diff | ||
| mutable_variable_no_prop.rs | ||
| mutable_variable_unprop_assign.main.GVN.panic-abort.diff | ||
| mutable_variable_unprop_assign.main.GVN.panic-unwind.diff | ||
| mutable_variable_unprop_assign.rs | ||
| offset_of.concrete.GVN.panic-abort.diff | ||
| offset_of.concrete.GVN.panic-unwind.diff | ||
| offset_of.generic.GVN.panic-abort.diff | ||
| offset_of.generic.GVN.panic-unwind.diff | ||
| offset_of.rs | ||
| overwrite_with_const_with_params.rs | ||
| overwrite_with_const_with_params.size_of.GVN.diff | ||
| pointer_expose_provenance.main.GVN.panic-abort.diff | ||
| pointer_expose_provenance.main.GVN.panic-unwind.diff | ||
| pointer_expose_provenance.rs | ||
| read_immutable_static.main.GVN.diff | ||
| read_immutable_static.rs | ||
| ref_deref.main.GVN.diff | ||
| ref_deref.rs | ||
| ref_deref_project.main.GVN.diff | ||
| ref_deref_project.rs | ||
| reify_fn_ptr.main.GVN.diff | ||
| reify_fn_ptr.rs | ||
| repeat.main.GVN.32bit.panic-abort.diff | ||
| repeat.main.GVN.32bit.panic-unwind.diff | ||
| repeat.main.GVN.64bit.panic-abort.diff | ||
| repeat.main.GVN.64bit.panic-unwind.diff | ||
| repeat.rs | ||
| return_place.add.GVN.panic-abort.diff | ||
| return_place.add.GVN.panic-unwind.diff | ||
| return_place.add.PreCodegen.before.panic-abort.mir | ||
| return_place.add.PreCodegen.before.panic-unwind.mir | ||
| return_place.rs | ||
| scalar_literal_propagation.main.GVN.panic-abort.diff | ||
| scalar_literal_propagation.main.GVN.panic-unwind.diff | ||
| scalar_literal_propagation.rs | ||
| slice_len.main.GVN.32bit.panic-abort.diff | ||
| slice_len.main.GVN.32bit.panic-unwind.diff | ||
| slice_len.main.GVN.64bit.panic-abort.diff | ||
| slice_len.main.GVN.64bit.panic-unwind.diff | ||
| slice_len.rs | ||
| switch_int.main.GVN.panic-abort.diff | ||
| switch_int.main.GVN.panic-unwind.diff | ||
| switch_int.main.SimplifyConstCondition-after-const-prop.panic-abort.diff | ||
| switch_int.main.SimplifyConstCondition-after-const-prop.panic-unwind.diff | ||
| switch_int.rs | ||
| transmute.from_char.GVN.32bit.diff | ||
| transmute.from_char.GVN.64bit.diff | ||
| transmute.invalid_bool.GVN.32bit.diff | ||
| transmute.invalid_bool.GVN.64bit.diff | ||
| transmute.invalid_char.GVN.32bit.diff | ||
| transmute.invalid_char.GVN.64bit.diff | ||
| transmute.less_as_i8.GVN.32bit.diff | ||
| transmute.less_as_i8.GVN.64bit.diff | ||
| transmute.rs | ||
| transmute.undef_union_as_integer.GVN.32bit.diff | ||
| transmute.undef_union_as_integer.GVN.64bit.diff | ||
| transmute.unreachable_box.GVN.32bit.diff | ||
| transmute.unreachable_box.GVN.64bit.diff | ||
| transmute.unreachable_direct.GVN.32bit.diff | ||
| transmute.unreachable_direct.GVN.64bit.diff | ||
| transmute.unreachable_mut.GVN.32bit.diff | ||
| transmute.unreachable_mut.GVN.64bit.diff | ||
| transmute.unreachable_ref.GVN.32bit.diff | ||
| transmute.unreachable_ref.GVN.64bit.diff | ||
| transmute.valid_char.GVN.32bit.diff | ||
| transmute.valid_char.GVN.64bit.diff | ||
| tuple_literal_propagation.main.GVN.panic-abort.diff | ||
| tuple_literal_propagation.main.GVN.panic-unwind.diff | ||
| tuple_literal_propagation.rs | ||
| while_let_loops.change_loop_body.GVN.diff | ||
| while_let_loops.rs | ||