Auto merge of #68404 - Amanieu:llvm-asm, r=estebank

Rename asm! to llvm_asm!

As per rust-lang/rfcs#2843, this PR renames `asm!` to `llvm_asm!`. It also renames the compiler's internal `InlineAsm` data structures to `LlvmInlineAsm` in preparation for the new `asm!` functionality specified in rust-lang/rfcs#2850.

This PR doesn't actually deprecate `asm!` yet, it just makes it redirect to `llvm_asm!`. This is necessary because we first need to update the submodules (in particular stdarch) to use `llvm_asm!`.

Author: bors

src/doc/unstable-book/src/library-features/asm.md renamed to src/doc/unstable-book/src/library-features/llvm-asm.md

@@ -1,25 +1,25 @@
-# `asm`
+# `llvm_asm`
 
-The tracking issue for this feature is: [#29722]
+The tracking issue for this feature is: [#70173]
 
-[#29722]: https://github.com/rust-lang/rust/issues/29722
+[#70173]: https://github.com/rust-lang/rust/issues/70173
 
 ------------------------
 
 For extremely low-level manipulations and performance reasons, one
 might wish to control the CPU directly. Rust supports using inline
-assembly to do this via the `asm!` macro.
+assembly to do this via the `llvm_asm!` macro.
 
 ```rust,ignore
-asm!(assembly template
+llvm_asm!(assembly template
    : output operands
    : input operands
    : clobbers
    : options
    );
 ```
 
-Any use of `asm` is feature gated (requires `#![feature(asm)]` on the
+Any use of `llvm_asm` is feature gated (requires `#![feature(llvm_asm)]` on the
 crate to allow) and of course requires an `unsafe` block.
 
 > **Note**: the examples here are given in x86/x86-64 assembly, but
@@ -31,12 +31,12 @@ The `assembly template` is the only required parameter and must be a
 literal string (i.e. `""`)
 
 ```rust
-#![feature(asm)]
+#![feature(llvm_asm)]
 
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 fn foo() {
     unsafe {
-        asm!("NOP");
+        llvm_asm!("NOP");
     }
 }
 
@@ -51,16 +51,16 @@ fn main() {
 }
 ```
 
-(The `feature(asm)` and `#[cfg]`s are omitted from now on.)
+(The `feature(llvm_asm)` and `#[cfg]`s are omitted from now on.)
 
 Output operands, input operands, clobbers and options are all optional
 but you must add the right number of `:` if you skip them:
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 # fn main() { unsafe {
-asm!("xor %eax, %eax"
+llvm_asm!("xor %eax, %eax"
     :
     :
     : "eax"
@@ -73,10 +73,10 @@ asm!("xor %eax, %eax"
 Whitespace also doesn't matter:
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 # fn main() { unsafe {
-asm!("xor %eax, %eax" ::: "eax");
+llvm_asm!("xor %eax, %eax" ::: "eax");
 # } }
 # #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
 # fn main() {}
@@ -89,12 +89,12 @@ Input and output operands follow the same format: `:
 expressions must be mutable lvalues, or not yet assigned:
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 fn add(a: i32, b: i32) -> i32 {
     let c: i32;
     unsafe {
-        asm!("add $2, $0"
+        llvm_asm!("add $2, $0"
              : "=r"(c)
              : "0"(a), "r"(b)
              );
@@ -116,11 +116,11 @@ operand. This is useful for very low level programming, where
 which register you use is important:
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 # unsafe fn read_byte_in(port: u16) -> u8 {
 let result: u8;
-asm!("in %dx, %al" : "={al}"(result) : "{dx}"(port));
+llvm_asm!("in %dx, %al" : "={al}"(result) : "{dx}"(port));
 result
 # }
 ```
@@ -133,11 +133,11 @@ compiler not to assume any values loaded into those registers will
 stay valid.
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 # fn main() { unsafe {
 // Put the value 0x200 in eax:
-asm!("mov $$0x200, %eax" : /* no outputs */ : /* no inputs */ : "eax");
+llvm_asm!("mov $$0x200, %eax" : /* no outputs */ : /* no inputs */ : "eax");
 # } }
 # #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
 # fn main() {}
@@ -167,12 +167,12 @@ Current valid options are:
 3. *intel* - use intel syntax instead of the default AT&T.
 
 ```rust
-# #![feature(asm)]
+# #![feature(llvm_asm)]
 # #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 # fn main() {
 let result: i32;
 unsafe {
-   asm!("mov eax, 2" : "={eax}"(result) : : : "intel")
+   llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")
 }
 println!("eax is currently {}", result);
 # }
@@ -182,12 +182,12 @@ println!("eax is currently {}", result);
 
 ## More Information
 
-The current implementation of the `asm!` macro is a direct binding to [LLVM's
+The current implementation of the `llvm_asm!` macro is a direct binding to [LLVM's
 inline assembler expressions][llvm-docs], so be sure to check out [their
 documentation as well][llvm-docs] for more information about clobbers,
 constraints, etc.
 
 [llvm-docs]: http://llvm.org/docs/LangRef.html#inline-assembler-expressions
 
 If you need more power and don't mind losing some of the niceties of
-`asm!`, check out [global_asm](global-asm.md).
+`llvm_asm!`, check out [global_asm](global-asm.md).

src/libcore/hint.rs

@@ -113,7 +113,7 @@ pub fn black_box<T>(dummy: T) -> T {
     // box. This isn't the greatest implementation since it probably deoptimizes
     // more than we want, but it's so far good enough.
     unsafe {
-        asm!("" : : "r"(&dummy));
+        llvm_asm!("" : : "r"(&dummy));
         dummy
     }
 }

src/libcore/lib.rs

@@ -98,6 +98,7 @@
 #![feature(is_sorted)]
 #![feature(lang_items)]
 #![feature(link_llvm_intrinsics)]
+#![feature(llvm_asm)]
 #![cfg_attr(not(bootstrap), feature(negative_impls))]
 #![feature(never_type)]
 #![feature(nll)]

src/libcore/macros/mod.rs

@@ -1307,7 +1307,7 @@ pub(crate) mod builtin {
     /// [unstable book]: ../unstable-book/library-features/asm.html
     #[unstable(
         feature = "asm",
-        issue = "29722",
+        issue = "70173",
         reason = "inline assembly is not stable enough for use and is subject to change"
     )]
     #[rustc_builtin_macro]
@@ -1322,6 +1322,47 @@ pub(crate) mod builtin {
         };
     }
 
+    /// Inline assembly.
+    ///
+    /// Read the [unstable book] for the usage.
+    ///
+    /// [unstable book]: ../unstable-book/library-features/asm.html
+    #[cfg(bootstrap)]
+    #[unstable(
+        feature = "llvm_asm",
+        issue = "70173",
+        reason = "inline assembly is not stable enough for use and is subject to change"
+    )]
+    #[macro_export]
+    #[allow_internal_unstable(asm)]
+    macro_rules! llvm_asm {
+        // Redirect to asm! for stage0
+        ($($arg:tt)*) => { $crate::asm!($($arg)*) }
+    }
+
+    /// Inline assembly.
+    ///
+    /// Read the [unstable book] for the usage.
+    ///
+    /// [unstable book]: ../unstable-book/library-features/asm.html
+    #[cfg(not(bootstrap))]
+    #[unstable(
+        feature = "llvm_asm",
+        issue = "70173",
+        reason = "inline assembly is not stable enough for use and is subject to change"
+    )]
+    #[rustc_builtin_macro]
+    #[macro_export]
+    macro_rules! llvm_asm {
+        ("assembly template"
+                        : $("output"(operand),)*
+                        : $("input"(operand),)*
+                        : $("clobbers",)*
+                        : $("options",)*) => {
+            /* compiler built-in */
+        };
+    }
+
     /// Module-level inline assembly.
     #[unstable(
         feature = "global_asm",

src/libcore/num/dec2flt/algorithm.rs

@@ -60,7 +60,7 @@ mod fpu_precision {
     fn set_cw(cw: u16) {
         // SAFETY: the `fldcw` instruction has been audited to be able to work correctly with
         // any `u16`
-        unsafe { asm!("fldcw $0" :: "m" (cw) :: "volatile") }
+        unsafe { llvm_asm!("fldcw $0" :: "m" (cw) :: "volatile") }
     }
 
     /// Sets the precision field of the FPU to `T` and returns a `FPUControlWord`.
@@ -78,7 +78,7 @@ mod fpu_precision {
         // `FPUControlWord` structure is dropped
         // SAFETY: the `fnstcw` instruction has been audited to be able to work correctly with
         // any `u16`
-        unsafe { asm!("fnstcw $0" : "=*m" (&cw) ::: "volatile") }
+        unsafe { llvm_asm!("fnstcw $0" : "=*m" (&cw) ::: "volatile") }
 
         // Set the control word to the desired precision. This is achieved by masking away the old
         // precision (bits 8 and 9, 0x300) and replacing it with the precision flag computed above.

src/libcore/prelude/v1.rs

@@ -57,8 +57,8 @@ pub use crate::hash::macros::Hash;
 #[doc(no_inline)]
 pub use crate::{
     asm, assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args,
-    format_args_nl, global_asm, include, include_bytes, include_str, line, log_syntax, module_path,
-    option_env, stringify, trace_macros,
+    format_args_nl, global_asm, include, include_bytes, include_str, line, llvm_asm, log_syntax,
+    module_path, option_env, stringify, trace_macros,
 };
 
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]

src/librustc/mir/mod.rs

@@ -1584,7 +1584,7 @@ pub enum StatementKind<'tcx> {
 
     /// Executes a piece of inline Assembly. Stored in a Box to keep the size
     /// of `StatementKind` low.
-    InlineAsm(Box<InlineAsm<'tcx>>),
+    LlvmInlineAsm(Box<LlvmInlineAsm<'tcx>>),
 
     /// Retag references in the given place, ensuring they got fresh tags. This is
     /// part of the Stacked Borrows model. These statements are currently only interpreted
@@ -1668,8 +1668,8 @@ pub enum FakeReadCause {
 }
 
 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
-pub struct InlineAsm<'tcx> {
-    pub asm: hir::InlineAsmInner,
+pub struct LlvmInlineAsm<'tcx> {
+    pub asm: hir::LlvmInlineAsmInner,
     pub outputs: Box<[Place<'tcx>]>,
     pub inputs: Box<[(Span, Operand<'tcx>)]>,
 }
@@ -1696,8 +1696,8 @@ impl Debug for Statement<'_> {
             SetDiscriminant { ref place, variant_index } => {
                 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
             }
-            InlineAsm(ref asm) => {
-                write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
+            LlvmInlineAsm(ref asm) => {
+                write!(fmt, "llvm_asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
             }
             AscribeUserType(box (ref place, ref c_ty), ref variance) => {
                 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)

src/librustc/mir/visit.rs

@@ -385,7 +385,7 @@ macro_rules! make_mir_visitor {
                             location
                         );
                     }
-                    StatementKind::InlineAsm(asm) => {
+                    StatementKind::LlvmInlineAsm(asm) => {
                         for output in & $($mutability)? asm.outputs[..] {
                             self.visit_place(
                                 output,

src/librustc/ty/structural_impls.rs

@@ -263,7 +263,7 @@ CloneTypeFoldableAndLiftImpls! {
     ::rustc_span::symbol::Symbol,
     ::rustc_hir::def::Res,
     ::rustc_hir::def_id::DefId,
-    ::rustc_hir::InlineAsmInner,
+    ::rustc_hir::LlvmInlineAsmInner,
     ::rustc_hir::MatchSource,
     ::rustc_hir::Mutability,
     ::rustc_hir::Unsafety,

src/librustc_ast/ast.rs

@@ -1114,7 +1114,7 @@ impl Expr {
             ExprKind::Break(..) => ExprPrecedence::Break,
             ExprKind::Continue(..) => ExprPrecedence::Continue,
             ExprKind::Ret(..) => ExprPrecedence::Ret,
-            ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
+            ExprKind::LlvmInlineAsm(..) => ExprPrecedence::InlineAsm,
             ExprKind::MacCall(..) => ExprPrecedence::Mac,
             ExprKind::Struct(..) => ExprPrecedence::Struct,
             ExprKind::Repeat(..) => ExprPrecedence::Repeat,
@@ -1243,8 +1243,8 @@ pub enum ExprKind {
     /// A `return`, with an optional value to be returned.
     Ret(Option<P<Expr>>),
 
-    /// Output of the `asm!()` macro.
-    InlineAsm(P<InlineAsm>),
+    /// Output of the `llvm_asm!()` macro.
+    LlvmInlineAsm(P<LlvmInlineAsm>),
 
     /// A macro invocation; pre-expansion.
     MacCall(MacCall),
@@ -1860,37 +1860,37 @@ pub enum TraitObjectSyntax {
 
 /// Inline assembly dialect.
 ///
-/// E.g., `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
+/// E.g., `"intel"` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
-pub enum AsmDialect {
+pub enum LlvmAsmDialect {
     Att,
     Intel,
 }
 
-/// Inline assembly.
+/// LLVM-style inline assembly.
 ///
-/// E.g., `"={eax}"(result)` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
+/// E.g., `"={eax}"(result)` as in `llvm_asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct InlineAsmOutput {
+pub struct LlvmInlineAsmOutput {
     pub constraint: Symbol,
     pub expr: P<Expr>,
     pub is_rw: bool,
     pub is_indirect: bool,
 }
 
-/// Inline assembly.
+/// LLVM-style inline assembly.
 ///
-/// E.g., `asm!("NOP");`.
+/// E.g., `llvm_asm!("NOP");`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct InlineAsm {
+pub struct LlvmInlineAsm {
     pub asm: Symbol,
     pub asm_str_style: StrStyle,
-    pub outputs: Vec<InlineAsmOutput>,
+    pub outputs: Vec<LlvmInlineAsmOutput>,
     pub inputs: Vec<(Symbol, P<Expr>)>,
     pub clobbers: Vec<Symbol>,
     pub volatile: bool,
     pub alignstack: bool,
-    pub dialect: AsmDialect,
+    pub dialect: LlvmAsmDialect,
 }
 
 /// A parameter in a function header.