ac24299636
The `mir!` macro has multiple parts:
- An optional return type annotation.
- A sequence of zero or more local declarations.
- A mandatory starting anonymous basic block, which is brace-delimited.
- A sequence of zero of more additional named basic blocks.
Some `mir!` invocations use braces with a "block" style, like so:
```
mir! {
let _unit: ();
{
let non_copy = S(42);
let ptr = std::ptr::addr_of_mut!(non_copy);
// Inside `callee`, the first argument and `*ptr` are basically
// aliasing places!
Call(_unit = callee(Move(*ptr), ptr), ReturnTo(after_call), UnwindContinue())
}
after_call = {
Return()
}
}
```
Some invocations use parens with a "block" style, like so:
```
mir!(
let x: [i32; 2];
let one: i32;
{
x = [42, 43];
one = 1;
x = [one, 2];
RET = Move(x);
Return()
}
)
```
And some invocations uses parens with a "tighter" style, like so:
```
mir!({
SetDiscriminant(*b, 0);
Return()
})
```
This last style is generally used for cases where just the mandatory
starting basic block is present. Its braces are placed next to the
parens.
This commit changes all `mir!` invocations to use braces with a "block"
style. Why?
- Consistency is good.
- The contents of the invocation is a block of code, so it's odd to use
parens. They are more normally used for function-like macros.
- Most importantly, the next commit will enable rustfmt for
`tests/mir-opt/`. rustfmt is more aggressive about formatting macros
that use parens than macros that use braces. Without this commit's
changes, rustfmt would break a couple of `mir!` macro invocations that
use braces within `tests/mir-opt` by inserting an extraneous comma.
E.g.:
```
mir!(type RET = (i32, bool);, { // extraneous comma after ';'
RET.0 = 1;
RET.1 = true;
Return()
})
```
Switching those `mir!` invocations to use braces avoids that problem,
resulting in this, which is nicer to read as well as being valid
syntax:
```
mir! {
type RET = (i32, bool);
{
RET.0 = 1;
RET.1 = true;
Return()
}
}
```
127 lines
2.4 KiB
Rust
127 lines
2.4 KiB
Rust
// skip-filecheck
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#![feature(custom_mir, core_intrinsics)]
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extern crate core;
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use core::intrinsics::mir::*;
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// EMIT_MIR enums.switch_bool.built.after.mir
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#[custom_mir(dialect = "built")]
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pub fn switch_bool(b: bool) -> u32 {
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mir! {
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{
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match b {
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true => t,
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false => f,
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_ => f,
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}
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}
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t = {
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RET = 5;
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Return()
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}
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f = {
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RET = 10;
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Return()
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}
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}
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}
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// EMIT_MIR enums.switch_option.built.after.mir
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#[custom_mir(dialect = "built")]
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pub fn switch_option(option: Option<()>) -> bool {
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mir! {
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{
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let discr = Discriminant(option);
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match discr {
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0 => n,
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1 => s,
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_ => s,
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}
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}
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n = {
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RET = false;
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Return()
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}
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s = {
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RET = true;
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Return()
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}
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}
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}
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#[repr(u8)]
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enum Bool {
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False = 0,
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True = 1,
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}
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// EMIT_MIR enums.switch_option_repr.built.after.mir
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#[custom_mir(dialect = "built")]
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fn switch_option_repr(option: Bool) -> bool {
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mir! {
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{
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let discr = Discriminant(option);
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match discr {
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0 => f,
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_ => t,
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}
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}
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t = {
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RET = true;
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Return()
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}
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f = {
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RET = false;
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Return()
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}
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}
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}
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// EMIT_MIR enums.set_discr.built.after.mir
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#[custom_mir(dialect = "runtime", phase = "initial")]
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fn set_discr(option: &mut Option<()>) {
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mir! {
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{
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Deinit(*option);
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SetDiscriminant(*option, 0);
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Return()
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}
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}
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}
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// EMIT_MIR enums.set_discr_repr.built.after.mir
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#[custom_mir(dialect = "runtime", phase = "initial")]
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fn set_discr_repr(b: &mut Bool) {
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mir! {
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{
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SetDiscriminant(*b, 0);
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Return()
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}
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}
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}
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fn main() {
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assert_eq!(switch_bool(true), 5);
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assert_eq!(switch_bool(false), 10);
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assert_eq!(switch_option(Some(())), true);
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assert_eq!(switch_option(None), false);
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assert_eq!(switch_option_repr(Bool::True), true);
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assert_eq!(switch_option_repr(Bool::False), false);
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let mut opt = Some(());
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set_discr(&mut opt);
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assert_eq!(opt, None);
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let mut b = Bool::True;
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set_discr_repr(&mut b);
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assert!(matches!(b, Bool::False));
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}
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