Rollup merge of #115000 - RalfJung:custom-mir-call, r=compiler-errors,JakobDegen

custom_mir: change Call() terminator syntax to something more readable

I find our current syntax very hard to read -- I cannot even remember the order of arguments, and having the "next block" *before* the actual function call is very counter-intuitive IMO. So I suggest we use `Call(ret_val = function(v), next_block)` instead.

r? `@JakobDegen`

compiler/rustc_mir_build/src/build/custom/parse/instruction.rs

@@ -61,9 +61,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                 })
             },
             @call("mir_call", args) => {
-                let destination = self.parse_place(args[0])?;
-                let target = self.parse_block(args[1])?;
-                self.parse_call(args[2], destination, target)
+                self.parse_call(args)
             },
             ExprKind::Match { scrutinee, arms, .. } => {
                 let discr = self.parse_operand(*scrutinee)?;
@@ -109,13 +107,14 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
         Ok(SwitchTargets::new(values.into_iter().zip(targets), otherwise))
     }
 
-    fn parse_call(
-        &self,
-        expr_id: ExprId,
-        destination: Place<'tcx>,
-        target: BasicBlock,
-    ) -> PResult<TerminatorKind<'tcx>> {
-        parse_by_kind!(self, expr_id, _, "function call",
+    fn parse_call(&self, args: &[ExprId]) -> PResult<TerminatorKind<'tcx>> {
+        let (destination, call) = parse_by_kind!(self, args[0], _, "function call",
+            ExprKind::Assign { lhs, rhs } => (*lhs, *rhs),
+        );
+        let destination = self.parse_place(destination)?;
+        let target = self.parse_block(args[1])?;
+
+        parse_by_kind!(self, call, _, "function call",
             ExprKind::Call { fun, args, from_hir_call, fn_span, .. } => {
                 let fun = self.parse_operand(*fun)?;
                 let args = args

library/core/src/intrinsics/mir.rs

@@ -104,17 +104,18 @@
 //! }
 //!
 //! #[custom_mir(dialect = "runtime", phase = "optimized")]
+#![cfg_attr(bootstrap, doc = "#[cfg(any())]")] // disable the following function in doctests when `bootstrap` is set
 //! fn push_and_pop<T>(v: &mut Vec<T>, value: T) {
 //!     mir!(
-//!         let unused;
+//!         let _unused;
 //!         let popped;
 //!
 //!         {
-//!             Call(unused, pop, Vec::push(v, value))
+//!             Call(_unused = Vec::push(v, value), pop)
 //!         }
 //!
 //!         pop = {
-//!             Call(popped, drop, Vec::pop(v))
+//!             Call(popped = Vec::pop(v), drop)
 //!         }
 //!
 //!         drop = {
@@ -275,7 +276,7 @@ define!("mir_return", fn Return() -> BasicBlock);
 define!("mir_goto", fn Goto(destination: BasicBlock) -> BasicBlock);
 define!("mir_unreachable", fn Unreachable() -> BasicBlock);
 define!("mir_drop", fn Drop<T>(place: T, goto: BasicBlock));
-define!("mir_call", fn Call<T>(place: T, goto: BasicBlock, call: T));
+define!("mir_call", fn Call(call: (), goto: BasicBlock));
 define!("mir_storage_live", fn StorageLive<T>(local: T));
 define!("mir_storage_dead", fn StorageDead<T>(local: T));
 define!("mir_deinit", fn Deinit<T>(place: T));

src/tools/miri/tests/fail/function_calls/arg_inplace_mutate.rs

@@ -8,13 +8,13 @@ pub struct S(i32);
 #[custom_mir(dialect = "runtime", phase = "optimized")]
 fn main() {
     mir! {
-        let unit: ();
+        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, after_call, callee(Move(*ptr), ptr))
+            Call(_unit = callee(Move(*ptr), ptr), after_call)
         }
         after_call = {
             Return()

src/tools/miri/tests/fail/function_calls/arg_inplace_mutate.stack.stderr

@@ -10,7 +10,7 @@ help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
   --> $DIR/arg_inplace_mutate.rs:LL:CC
    |
 LL | /     mir! {
-LL | |         let unit: ();
+LL | |         let _unit: ();
 LL | |         {
 LL | |             let non_copy = S(42);
 ...  |
@@ -27,8 +27,8 @@ LL |     unsafe { ptr.write(S(0)) };
 note: inside `main`
   --> $DIR/arg_inplace_mutate.rs:LL:CC
    |
-LL |             Call(unit, after_call, callee(Move(*ptr), ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_unit = callee(Move(*ptr), ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/arg_inplace_mutate.tree.stderr

@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here
   --> $DIR/arg_inplace_mutate.rs:LL:CC
    |
 LL | /     mir! {
-LL | |         let unit: ();
+LL | |         let _unit: ();
 LL | |         {
 LL | |             let non_copy = S(42);
 ...  |
@@ -29,8 +29,8 @@ LL |     unsafe { ptr.write(S(0)) };
 note: inside `main`
   --> $DIR/arg_inplace_mutate.rs:LL:CC
    |
-LL |             Call(unit, after_call, callee(Move(*ptr), ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_unit = callee(Move(*ptr), ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/arg_inplace_observe_after.rs

@@ -6,12 +6,12 @@ pub struct S(i32);
 #[custom_mir(dialect = "runtime", phase = "optimized")]
 fn main() {
     mir! {
-        let unit: ();
+        let _unit: ();
         let _observe: i32;
         {
             let non_copy = S(42);
             // This could change `non_copy` in-place
-            Call(unit, after_call, change_arg(Move(non_copy)))
+            Call(_unit = change_arg(Move(non_copy)), after_call)
         }
         after_call = {
             // So now we must not be allowed to observe non-copy again.

src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.none.stderr

@@ -11,8 +11,8 @@ LL |     unsafe { ptr.read() };
 note: inside `main`
   --> $DIR/arg_inplace_observe_during.rs:LL:CC
    |
-LL |             Call(unit, after_call, change_arg(Move(*ptr), ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_unit = change_arg(Move(*ptr), ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.rs

@@ -9,12 +9,12 @@ pub struct S(i32);
 #[custom_mir(dialect = "runtime", phase = "optimized")]
 fn main() {
     mir! {
-        let unit: ();
+        let _unit: ();
         {
             let non_copy = S(42);
             let ptr = std::ptr::addr_of_mut!(non_copy);
             // This could change `non_copy` in-place
-            Call(unit, after_call, change_arg(Move(*ptr), ptr))
+            Call(_unit = change_arg(Move(*ptr), ptr), after_call)
         }
         after_call = {
             Return()

src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.stack.stderr

@@ -10,7 +10,7 @@ help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
   --> $DIR/arg_inplace_observe_during.rs:LL:CC
    |
 LL | /     mir! {
-LL | |         let unit: ();
+LL | |         let _unit: ();
 LL | |         {
 LL | |             let non_copy = S(42);
 ...  |
@@ -27,8 +27,8 @@ LL |     x.0 = 0;
 note: inside `main`
   --> $DIR/arg_inplace_observe_during.rs:LL:CC
    |
-LL |             Call(unit, after_call, change_arg(Move(*ptr), ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_unit = change_arg(Move(*ptr), ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/arg_inplace_observe_during.tree.stderr

@@ -12,7 +12,7 @@ help: the accessed tag <TAG> was created here
   --> $DIR/arg_inplace_observe_during.rs:LL:CC
    |
 LL | /     mir! {
-LL | |         let unit: ();
+LL | |         let _unit: ();
 LL | |         {
 LL | |             let non_copy = S(42);
 ...  |
@@ -29,8 +29,8 @@ LL |     x.0 = 0;
 note: inside `main`
   --> $DIR/arg_inplace_observe_during.rs:LL:CC
    |
-LL |             Call(unit, after_call, change_arg(Move(*ptr), ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_unit = change_arg(Move(*ptr), ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing.none.stderr

@@ -11,8 +11,8 @@ LL |     unsafe { ptr.read() };
 note: inside `main`
   --> $DIR/return_pointer_aliasing.rs:LL:CC
    |
-LL |             Call(*ptr, after_call, myfun(ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(*ptr = myfun(ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing.rs

@@ -15,7 +15,7 @@ pub fn main() {
             let ptr = &raw mut x;
             // We arrange for `myfun` to have a pointer that aliases
             // its return place. Even just reading from that pointer is UB.
-            Call(*ptr, after_call, myfun(ptr))
+            Call(*ptr = myfun(ptr), after_call)
         }
 
         after_call = {

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing.stack.stderr

@@ -27,8 +27,8 @@ LL |     unsafe { ptr.read() };
 note: inside `main`
   --> $DIR/return_pointer_aliasing.rs:LL:CC
    |
-LL |             Call(*ptr, after_call, myfun(ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(*ptr = myfun(ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing.tree.stderr

@@ -29,8 +29,8 @@ LL |     unsafe { ptr.read() };
 note: inside `main`
   --> $DIR/return_pointer_aliasing.rs:LL:CC
    |
-LL |             Call(*ptr, after_call, myfun(ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(*ptr = myfun(ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing2.rs

@@ -9,11 +9,11 @@ use std::intrinsics::mir::*;
 pub fn main() {
     mir! {
         {
-            let x = 0;
-            let ptr = &raw mut x;
+            let _x = 0;
+            let ptr = &raw mut _x;
             // We arrange for `myfun` to have a pointer that aliases
             // its return place. Even just reading from that pointer is UB.
-            Call(x, after_call, myfun(ptr))
+            Call(_x = myfun(ptr), after_call)
         }
 
         after_call = {

src/tools/miri/tests/fail/function_calls/return_pointer_aliasing2.stderr

@@ -13,8 +13,8 @@ help: the accessed tag <TAG> was created here
    |
 LL | /     mir! {
 LL | |         {
-LL | |             let x = 0;
-LL | |             let ptr = &raw mut x;
+LL | |             let _x = 0;
+LL | |             let ptr = &raw mut _x;
 ...  |
 LL | |         }
 LL | |     }
@@ -29,8 +29,8 @@ LL |     unsafe { ptr.write(0) };
 note: inside `main`
   --> $DIR/return_pointer_aliasing2.rs:LL:CC
    |
-LL |             Call(x, after_call, myfun(ptr))
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |             Call(_x = myfun(ptr), after_call)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in the macro `::core::intrinsics::mir::__internal_remove_let` which comes from the expansion of the macro `mir` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/pass/function_calls/return_place_on_heap.rs

@@ -11,7 +11,7 @@ pub fn main() {
         {
             let x = 0;
             let ptr = &raw mut x;
-            Call(*ptr, after_call, myfun())
+            Call(*ptr = myfun(), after_call)
         }
 
         after_call = {

tests/mir-opt/building/custom/terminators.rs

@@ -12,7 +12,7 @@ fn ident<T>(t: T) -> T {
 fn direct_call(x: i32) -> i32 {
     mir!(
         {
-            Call(RET, retblock, ident(x))
+            Call(RET = ident(x), retblock)
         }
 
         retblock = {
@@ -26,7 +26,7 @@ fn direct_call(x: i32) -> i32 {
 fn indirect_call(x: i32, f: fn(i32) -> i32) -> i32 {
     mir!(
         {
-            Call(RET, retblock, f(x))
+            Call(RET = f(x), retblock)
         }
 
         retblock = {

tests/mir-opt/copy-prop/borrowed_local.rs

@@ -21,11 +21,11 @@ fn f() -> bool {
             let b = a;
             // We cannot propagate the place `a`.
             let r2 = &b;
-            Call(RET, next, cmp_ref(r1, r2))
+            Call(RET = cmp_ref(r1, r2), next)
         }
         next = {
             // But we can propagate the value `a`.
-            Call(RET, ret, opaque(b))
+            Call(RET = opaque(b), ret)
         }
         ret = {
             Return()

tests/mir-opt/copy-prop/custom_move_arg.rs

@@ -13,11 +13,11 @@ struct NotCopy(bool);
 fn f(_1: NotCopy) {
     mir!({
         let _2 = _1;
-        Call(RET, bb1, opaque(Move(_1)))
+        Call(RET = opaque(Move(_1)), bb1)
     }
     bb1 = {
         let _3 = Move(_2);
-        Call(RET, bb2, opaque(_3))
+        Call(RET = opaque(_3), bb2)
     }
     bb2 = {
         Return()

tests/mir-opt/copy-prop/move_projection.rs

@@ -17,10 +17,10 @@ fn f(a: Foo) -> bool {
             let b = a;
             // This is a move out of a copy, so must become a copy of `a.0`.
             let c = Move(b.0);
-            Call(RET, bb1, opaque(Move(a)))
+            Call(RET = opaque(Move(a)), bb1)
         }
         bb1 = {
-            Call(RET, ret, opaque(Move(c)))
+            Call(RET = opaque(Move(c)), ret)
         }
         ret = {
             Return()

tests/mir-opt/reference_prop.rs

@@ -426,7 +426,7 @@ fn multiple_storage() {
             // As there are multiple `StorageLive` statements for `x`, we cannot know if this `z`'s
             // pointer address is the address of `x`, so do nothing.
             let y = *z;
-            Call(RET, retblock, opaque(y))
+            Call(RET = opaque(y), retblock)
         }
 
         retblock = {
@@ -452,7 +452,7 @@ fn dominate_storage() {
         }
         bb1 = {
             let c = *r;
-            Call(RET, bb2, opaque(c))
+            Call(RET = opaque(c), bb2)
         }
         bb2 = {
             StorageDead(x);
@@ -486,18 +486,18 @@ fn maybe_dead(m: bool) {
         bb1 = {
             StorageDead(x);
             StorageDead(y);
-            Call(RET, bb2, opaque(u))
+            Call(RET = opaque(u), bb2)
         }
         bb2 = {
             // As `x` may be `StorageDead`, `a` may be dangling, so we do nothing.
             let z = *a;
-            Call(RET, bb3, opaque(z))
+            Call(RET = opaque(z), bb3)
         }
         bb3 = {
             // As `y` may be `StorageDead`, `b` may be dangling, so we do nothing.
             // This implies that we also do not substitute `b` in `bb0`.
             let t = *b;
-            Call(RET, retblock, opaque(t))
+            Call(RET = opaque(t), retblock)
         }
         retblock = {
             Return()