Auto merge of #92816 - tmiasko:rm-llvm-asm, r=Amanieu

Remove deprecated LLVM-style inline assembly

The `llvm_asm!` was deprecated back in #87590 1.56.0, with intention to remove
it once `asm!` was stabilized, which already happened in #91728 1.59.0. Now it
is time to remove `llvm_asm!` to avoid continued maintenance cost.

Closes #70173.
Closes #92794.
Closes #87612.
Closes #82065.

cc `@rust-lang/wg-inline-asm`

r? `@Amanieu`

3 files changed, 0 insertions, 314 deletions

diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs
index caf8ac77df1..1a6e5694791 100644
--- a/compiler/rustc_builtin_macros/src/asm.rs
+++ b/compiler/rustc_builtin_macros/src/asm.rs
@@ -50,15 +50,6 @@ pub fn parse_asm_args<'a>(
         return Err(diag.struct_span_err(sp, "requires at least a template string argument"));
     }
 
-    // Detect use of the legacy llvm_asm! syntax (which used to be called asm!)
-    if !is_global_asm && p.look_ahead(1, |t| *t == token::Colon || *t == token::ModSep) {
-        let mut err =
-            diag.struct_span_err(sp, "the legacy LLVM-style asm! syntax is no longer supported");
-        err.note("consider migrating to the new asm! syntax specified in RFC 2873");
-        err.note("alternatively, switch to llvm_asm! to keep your code working as it is");
-        return Err(err);
-    }
-
     let first_template = p.parse_expr()?;
     let mut args = AsmArgs {
         templates: vec![first_template],
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 8c3ef2864f4..65f785b9097 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -33,7 +33,6 @@ mod env;
 mod format;
 mod format_foreign;
 mod global_allocator;
-mod llvm_asm;
 mod log_syntax;
 mod panic;
 mod source_util;
@@ -78,7 +77,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         include_str: source_util::expand_include_str,
         include: source_util::expand_include,
         line: source_util::expand_line,
-        llvm_asm: llvm_asm::expand_llvm_asm,
         log_syntax: log_syntax::expand_log_syntax,
         module_path: source_util::expand_mod,
         option_env: env::expand_option_env,
diff --git a/compiler/rustc_builtin_macros/src/llvm_asm.rs b/compiler/rustc_builtin_macros/src/llvm_asm.rs
deleted file mode 100644
index d72bfa660e5..00000000000
--- a/compiler/rustc_builtin_macros/src/llvm_asm.rs
+++ /dev/null
@@ -1,303 +0,0 @@
-// Llvm-style inline assembly support.
-//
-use State::*;
-
-use rustc_ast as ast;
-use rustc_ast::ptr::P;
-use rustc_ast::token::{self, Token};
-use rustc_ast::tokenstream::{self, TokenStream};
-use rustc_ast::LlvmAsmDialect;
-use rustc_errors::{struct_span_err, DiagnosticBuilder, PResult};
-use rustc_expand::base::*;
-use rustc_parse::parser::Parser;
-use rustc_span::symbol::{kw, sym, Symbol};
-use rustc_span::Span;
-
-enum State {
-    Asm,
-    Outputs,
-    Inputs,
-    Clobbers,
-    Options,
-    StateNone,
-}
-
-impl State {
-    fn next(&self) -> State {
-        match *self {
-            Asm => Outputs,
-            Outputs => Inputs,
-            Inputs => Clobbers,
-            Clobbers => Options,
-            Options => StateNone,
-            StateNone => StateNone,
-        }
-    }
-}
-
-const OPTIONS: &[Symbol] = &[sym::volatile, sym::alignstack, sym::intel];
-
-pub fn expand_llvm_asm<'cx>(
-    cx: &'cx mut ExtCtxt<'_>,
-    sp: Span,
-    tts: TokenStream,
-) -> Box<dyn MacResult + 'cx> {
-    let mut inline_asm = match parse_inline_asm(cx, sp, tts) {
-        Ok(Some(inline_asm)) => inline_asm,
-        Ok(None) => return DummyResult::any(sp),
-        Err(mut err) => {
-            err.emit();
-            return DummyResult::any(sp);
-        }
-    };
-
-    // If there are no outputs, the inline assembly is executed just for its side effects,
-    // so ensure that it is volatile
-    if inline_asm.outputs.is_empty() {
-        inline_asm.volatile = true;
-    }
-
-    MacEager::expr(P(ast::Expr {
-        id: ast::DUMMY_NODE_ID,
-        kind: ast::ExprKind::LlvmInlineAsm(P(inline_asm)),
-        span: cx.with_def_site_ctxt(sp),
-        attrs: ast::AttrVec::new(),
-        tokens: None,
-    }))
-}
-
-fn parse_asm_str<'a>(p: &mut Parser<'a>) -> PResult<'a, Symbol> {
-    match p.parse_str_lit() {
-        Ok(str_lit) => Ok(str_lit.symbol_unescaped),
-        Err(opt_lit) => {
-            let span = opt_lit.map_or(p.token.span, |lit| lit.span);
-            let mut err = p.sess.span_diagnostic.struct_span_err(span, "expected string literal");
-            err.span_label(span, "not a string literal");
-            Err(err)
-        }
-    }
-}
-
-fn parse_inline_asm<'a>(
-    cx: &mut ExtCtxt<'a>,
-    sp: Span,
-    tts: TokenStream,
-) -> Result<Option<ast::LlvmInlineAsm>, DiagnosticBuilder<'a>> {
-    // Split the tts before the first colon, to avoid `llvm_asm!("x": y)`  being
-    // parsed as `llvm_asm!(z)` with `z = "x": y` which is type ascription.
-    let first_colon = tts
-        .trees()
-        .position(|tt| {
-            matches!(
-                tt,
-                tokenstream::TokenTree::Token(Token { kind: token::Colon | token::ModSep, .. })
-            )
-        })
-        .unwrap_or(tts.len());
-    let mut p = cx.new_parser_from_tts(tts.trees().skip(first_colon).collect());
-    let mut asm = kw::Empty;
-    let mut asm_str_style = None;
-    let mut outputs = Vec::new();
-    let mut inputs = Vec::new();
-    let mut clobs = Vec::new();
-    let mut volatile = false;
-    let mut alignstack = false;
-    let mut dialect = LlvmAsmDialect::Att;
-
-    let mut state = Asm;
-
-    'statement: loop {
-        match state {
-            Asm => {
-                if asm_str_style.is_some() {
-                    // If we already have a string with instructions,
-                    // ending up in Asm state again is an error.
-                    return Err(struct_span_err!(
-                        cx.sess.parse_sess.span_diagnostic,
-                        sp,
-                        E0660,
-                        "malformed inline assembly"
-                    ));
-                }
-                // Nested parser, stop before the first colon (see above).
-                let mut p2 = cx.new_parser_from_tts(tts.trees().take(first_colon).collect());
-
-                if p2.token == token::Eof {
-                    let mut err =
-                        cx.struct_span_err(sp, "macro requires a string literal as an argument");
-                    err.span_label(sp, "string literal required");
-                    return Err(err);
-                }
-
-                let expr = p2.parse_expr()?;
-                let (s, style) =
-                    match expr_to_string(cx, expr, "inline assembly must be a string literal") {
-                        Some((s, st)) => (s, st),
-                        None => return Ok(None),
-                    };
-
-                // This is most likely malformed.
-                if p2.token != token::Eof {
-                    let mut extra_tts = p2.parse_all_token_trees()?;
-                    extra_tts.extend(tts.trees().skip(first_colon));
-                    p = cx.new_parser_from_tts(extra_tts.into_iter().collect());
-                }
-
-                asm = s;
-                asm_str_style = Some(style);
-            }
-            Outputs => {
-                while p.token != token::Eof && p.token != token::Colon && p.token != token::ModSep {
-                    if !outputs.is_empty() {
-                        p.eat(&token::Comma);
-                    }
-
-                    let constraint = parse_asm_str(&mut p)?;
-
-                    let span = p.prev_token.span;
-
-                    p.expect(&token::OpenDelim(token::Paren))?;
-                    let expr = p.parse_expr()?;
-                    p.expect(&token::CloseDelim(token::Paren))?;
-
-                    // Expands a read+write operand into two operands.
-                    //
-                    // Use '+' modifier when you want the same expression
-                    // to be both an input and an output at the same time.
-                    // It's the opposite of '=&' which means that the memory
-                    // cannot be shared with any other operand (usually when
-                    // a register is clobbered early.)
-                    let constraint_str = constraint.as_str();
-                    let mut ch = constraint_str.chars();
-                    let output = match ch.next() {
-                        Some('=') => None,
-                        Some('+') => Some(Symbol::intern(&format!("={}", ch.as_str()))),
-                        _ => {
-                            struct_span_err!(
-                                cx.sess.parse_sess.span_diagnostic,
-                                span,
-                                E0661,
-                                "output operand constraint lacks '=' or '+'"
-                            )
-                            .emit();
-                            None
-                        }
-                    };
-
-                    let is_rw = output.is_some();
-                    let is_indirect = constraint_str.contains('*');
-                    outputs.push(ast::LlvmInlineAsmOutput {
-                        constraint: output.unwrap_or(constraint),
-                        expr,
-                        is_rw,
-                        is_indirect,
-                    });
-                }
-            }
-            Inputs => {
-                while p.token != token::Eof && p.token != token::Colon && p.token != token::ModSep {
-                    if !inputs.is_empty() {
-                        p.eat(&token::Comma);
-                    }
-
-                    let constraint = parse_asm_str(&mut p)?;
-
-                    if constraint.as_str().starts_with('=') {
-                        struct_span_err!(
-                            cx.sess.parse_sess.span_diagnostic,
-                            p.prev_token.span,
-                            E0662,
-                            "input operand constraint contains '='"
-                        )
-                        .emit();
-                    } else if constraint.as_str().starts_with('+') {
-                        struct_span_err!(
-                            cx.sess.parse_sess.span_diagnostic,
-                            p.prev_token.span,
-                            E0663,
-                            "input operand constraint contains '+'"
-                        )
-                        .emit();
-                    }
-
-                    p.expect(&token::OpenDelim(token::Paren))?;
-                    let input = p.parse_expr()?;
-                    p.expect(&token::CloseDelim(token::Paren))?;
-
-                    inputs.push((constraint, input));
-                }
-            }
-            Clobbers => {
-                while p.token != token::Eof && p.token != token::Colon && p.token != token::ModSep {
-                    if !clobs.is_empty() {
-                        p.eat(&token::Comma);
-                    }
-
-                    let s = parse_asm_str(&mut p)?;
-
-                    if OPTIONS.iter().any(|&opt| s == opt) {
-                        cx.span_warn(p.prev_token.span, "expected a clobber, found an option");
-                    } else if s.as_str().starts_with('{') || s.as_str().ends_with('}') {
-                        struct_span_err!(
-                            cx.sess.parse_sess.span_diagnostic,
-                            p.prev_token.span,
-                            E0664,
-                            "clobber should not be surrounded by braces"
-                        )
-                        .emit();
-                    }
-
-                    clobs.push(s);
-                }
-            }
-            Options => {
-                let option = parse_asm_str(&mut p)?;
-
-                if option == sym::volatile {
-                    // Indicates that the inline assembly has side effects
-                    // and must not be optimized out along with its outputs.
-                    volatile = true;
-                } else if option == sym::alignstack {
-                    alignstack = true;
-                } else if option == sym::intel {
-                    dialect = LlvmAsmDialect::Intel;
-                } else {
-                    cx.span_warn(p.prev_token.span, "unrecognized option");
-                }
-
-                if p.token == token::Comma {
-                    p.eat(&token::Comma);
-                }
-            }
-            StateNone => (),
-        }
-
-        loop {
-            // MOD_SEP is a double colon '::' without space in between.
-            // When encountered, the state must be advanced twice.
-            match (&p.token.kind, state.next(), state.next().next()) {
-                (&token::Colon, StateNone, _) | (&token::ModSep, _, StateNone) => {
-                    p.bump();
-                    break 'statement;
-                }
-                (&token::Colon, st, _) | (&token::ModSep, _, st) => {
-                    p.bump();
-                    state = st;
-                }
-                (&token::Eof, ..) => break 'statement,
-                _ => break,
-            }
-        }
-    }
-
-    Ok(Some(ast::LlvmInlineAsm {
-        asm,
-        asm_str_style: asm_str_style.unwrap(),
-        outputs,
-        inputs,
-        clobbers: clobs,
-        volatile,
-        alignstack,
-        dialect,
-    }))
-}