From 5dabc80796822c80223a2e51dcd8cd3c752dd6d9 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Wed, 24 Mar 2021 04:52:57 +0000
Subject: [PATCH] Refactor #82270 as lint instead of an error
---
compiler/rustc_builtin_macros/src/asm.rs | 95 +++++++--------------
compiler/rustc_lint_defs/src/builtin.rs | 46 ++++++++++
compiler/rustc_session/src/session.rs | 7 --
src/test/ui/asm/inline-syntax.arm.stderr | 74 ++++++++++++++--
src/test/ui/asm/inline-syntax.rs | 25 ++++--
src/test/ui/asm/inline-syntax.x86_64.stderr | 50 +++++------
6 files changed, 179 insertions(+), 118 deletions(-)
diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs
index 8d8b3f4f6aa..e6afc81d039 100644
--- a/compiler/rustc_builtin_macros/src/asm.rs
+++ b/compiler/rustc_builtin_macros/src/asm.rs
@@ -7,11 +7,10 @@ use rustc_errors::{Applicability, DiagnosticBuilder};
use rustc_expand::base::{self, *};
use rustc_parse::parser::Parser;
use rustc_parse_format as parse;
-use rustc_span::{
- symbol::{kw, sym, Symbol},
- BytePos,
-};
+use rustc_session::lint;
+use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::{InnerSpan, Span};
+use rustc_target::asm::InlineAsmArch;
struct AsmArgs {
templates: Vec<P<ast::Expr>>,
@@ -402,8 +401,6 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, sp: Span, args: AsmArgs) -> P<ast
let mut line_spans = Vec::with_capacity(args.templates.len());
let mut curarg = 0;
- let default_dialect = ecx.sess.inline_asm_dialect();
-
for template_expr in args.templates.into_iter() {
if !template.is_empty() {
template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
@@ -430,56 +427,36 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, sp: Span, args: AsmArgs) -> P<ast
let template_str = &template_str.as_str();
let template_snippet = ecx.source_map().span_to_snippet(template_sp).ok();
- if let Some(snippet) = &template_snippet {
- let snippet = snippet.trim_matches('"');
- match default_dialect {
- ast::LlvmAsmDialect::Intel => {
- if let Some(span) = check_syntax_directive(snippet, ".intel_syntax") {
- let span = template_span.from_inner(span);
- let mut err = ecx.struct_span_err(span, "intel syntax is the default syntax on this target, and trying to use this directive may cause issues");
- err.span_suggestion(
- span,
- "remove this assembler directive",
- "".to_string(),
- Applicability::MachineApplicable,
- );
- err.emit();
- }
-
- if let Some(span) = check_syntax_directive(snippet, ".att_syntax") {
- let span = template_span.from_inner(span);
- let mut err = ecx.struct_span_err(span, "using the .att_syntax directive may cause issues, use the att_syntax option instead");
- let asm_end = sp.hi() - BytePos(2);
- let suggestions = vec![
- (span, "".to_string()),
- (
- Span::new(asm_end, asm_end, sp.ctxt()),
- ", options(att_syntax)".to_string(),
- ),
- ];
- err.multipart_suggestion(
- "remove the assembler directive and replace it with options(att_syntax)",
- suggestions,
- Applicability::MachineApplicable,
- );
- err.emit();
+ if let Some(InlineAsmArch::X86 | InlineAsmArch::X86_64) = ecx.sess.asm_arch {
+ let find_span = |needle: &str| -> Span {
+ if let Some(snippet) = &template_snippet {
+ if let Some(pos) = snippet.find(needle) {
+ let end = pos
+ + &snippet[pos..]
+ .find(|c| matches!(c, '\n' | ';' | '\\' | '"'))
+ .unwrap_or(snippet[pos..].len() - 1);
+ let inner = InnerSpan::new(pos, end);
+ return template_sp.from_inner(inner);
}
}
- ast::LlvmAsmDialect::Att => {
- if let Some(span) = check_syntax_directive(snippet, ".att_syntax") {
- let span = template_span.from_inner(span);
- let mut err = ecx.struct_span_err(span, "att syntax is the default syntax on this target, and trying to use this directive may cause issues");
- err.span_suggestion(
- span,
- "remove this assembler directive",
- "".to_string(),
- Applicability::MachineApplicable,
- );
- err.emit();
- }
+ template_sp
+ };
- // Use of .intel_syntax is ignored
- }
+ if template_str.contains(".intel_syntax") {
+ ecx.parse_sess().buffer_lint(
+ lint::builtin::BAD_ASM_STYLE,
+ find_span(".intel_syntax"),
+ ecx.resolver.lint_node_id(ecx.current_expansion.id),
+ "avoid using `.intel_syntax`, Intel syntax is the default",
+ );
+ }
+ if template_str.contains(".att_syntax") {
+ ecx.parse_sess().buffer_lint(
+ lint::builtin::BAD_ASM_STYLE,
+ find_span(".att_syntax"),
+ ecx.resolver.lint_node_id(ecx.current_expansion.id),
+ "avoid using `.att_syntax`, prefer using `options(att_syntax)` instead",
+ );
}
}
@@ -690,15 +667,3 @@ pub fn expand_asm<'cx>(
}
}
}
-
-fn check_syntax_directive<S: AsRef<str>>(piece: S, syntax: &str) -> Option<InnerSpan> {
- let piece = piece.as_ref();
- if let Some(idx) = piece.find(syntax) {
- let end =
- idx + &piece[idx..].find(|c| matches!(c, '\n' | ';')).unwrap_or(piece[idx..].len());
- // Offset by one because these represent the span with the " removed
- Some(InnerSpan::new(idx + 1, end + 1))
- } else {
- None
- }
-}
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 005c4f9f6ea..cd4d01ddc05 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -2486,6 +2486,52 @@ declare_lint! {
"using only a subset of a register for inline asm inputs",
}
+declare_lint! {
+ /// The `bad_asm_style` lint detects the use of the `.intel_syntax` and
+ /// `.att_syntax` directives.
+ ///
+ /// ### Example
+ ///
+ /// ```rust,ignore (fails on system llvm)
+ /// #![feature(asm)]
+ ///
+ /// fn main() {
+ /// #[cfg(target_arch="x86_64")]
+ /// unsafe {
+ /// asm!(
+ /// ".att_syntax",
+ /// "movl {0}, {0}", in(reg) 0usize
+ /// );
+ /// }
+ /// }
+ /// ```
+ ///
+ /// This will produce:
+ ///
+ /// ```text
+ /// warning: avoid using `.att_syntax`, prefer using `options(att_syntax)` instead
+ /// --> test.rs:7:14
+ /// |
+ /// 7 | ".att_syntax",
+ /// | ^^^^^^^^^^^
+ /// 8 | "movq {0}, {0}", out(reg) _,
+ /// 9 | );
+ /// | - help: add option: `, options(att_syntax)`
+ /// |
+ /// = note: `#[warn(bad_asm_style)]` on by default
+ /// ```
+ ///
+ /// ### Explanation
+ ///
+ /// On x86, `asm!` uses the intel assembly syntax by default. While this
+ /// can be switched using assembler directives like `.att_syntax`, using the
+ /// `att_syntax` option is recomended instead because it will also properly
+ /// prefix register placeholders with `%` as required by AT&T syntax.
+ pub BAD_ASM_STYLE,
+ Warn,
+ "incorrect use of inline assembly",
+}
+
declare_lint! {
/// The `unsafe_op_in_unsafe_fn` lint detects unsafe operations in unsafe
/// functions without an explicit unsafe block.
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index fc57b6b8ace..4f611118360 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -793,13 +793,6 @@ impl Session {
}
}
- pub fn inline_asm_dialect(&self) -> rustc_ast::LlvmAsmDialect {
- match self.asm_arch {
- Some(InlineAsmArch::X86 | InlineAsmArch::X86_64) => rustc_ast::LlvmAsmDialect::Intel,
- _ => rustc_ast::LlvmAsmDialect::Att,
- }
- }
-
pub fn relocation_model(&self) -> RelocModel {
self.opts.cg.relocation_model.unwrap_or(self.target.relocation_model)
}
diff --git a/src/test/ui/asm/inline-syntax.arm.stderr b/src/test/ui/asm/inline-syntax.arm.stderr
index 78b85dfde33..56e6572fc67 100644
--- a/src/test/ui/asm/inline-syntax.arm.stderr
+++ b/src/test/ui/asm/inline-syntax.arm.stderr
@@ -1,14 +1,74 @@
-error: att syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:23:15
+error: unknown directive
+ --> $DIR/inline-syntax.rs:22:15
+ |
+LL | asm!(".intel_syntax noprefix", "nop");
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:1:2
+ |
+LL | .intel_syntax noprefix
+ | ^
+
+error: unknown directive
+ --> $DIR/inline-syntax.rs:25:15
+ |
+LL | asm!(".intel_syntax aaa noprefix", "nop");
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:1:2
+ |
+LL | .intel_syntax aaa noprefix
+ | ^
+
+error: unknown directive
+ --> $DIR/inline-syntax.rs:28:15
|
LL | asm!(".att_syntax noprefix", "nop");
- | ^^^^^^^^^^^^^^^^^^^^ help: remove this assembler directive
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:1:2
+ |
+LL | .att_syntax noprefix
+ | ^
-error: att syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:26:15
+error: unknown directive
+ --> $DIR/inline-syntax.rs:31:15
|
LL | asm!(".att_syntax bbb noprefix", "nop");
- | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this assembler directive
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:1:2
+ |
+LL | .att_syntax bbb noprefix
+ | ^
-error: aborting due to 2 previous errors
+error: unknown directive
+ --> $DIR/inline-syntax.rs:34:15
+ |
+LL | asm!(".intel_syntax noprefix; nop");
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:1:2
+ |
+LL | .intel_syntax noprefix; nop
+ | ^
+
+error: unknown directive
+ --> $DIR/inline-syntax.rs:40:13
+ |
+LL | .intel_syntax noprefix
+ | ^
+ |
+note: instantiated into assembly here
+ --> <inline asm>:2:13
+ |
+LL | .intel_syntax noprefix
+ | ^
+
+error: aborting due to 6 previous errors
diff --git a/src/test/ui/asm/inline-syntax.rs b/src/test/ui/asm/inline-syntax.rs
index 9048282456e..78dde5a58e1 100644
--- a/src/test/ui/asm/inline-syntax.rs
+++ b/src/test/ui/asm/inline-syntax.rs
@@ -1,9 +1,12 @@
// needs-llvm-components: arm
// revisions: x86_64 arm
//[x86_64] compile-flags: --target x86_64-unknown-linux-gnu
+//[x86_64] check-pass
//[arm] compile-flags: --target armv7-unknown-linux-gnueabihf
+//[arm] build-fail
#![feature(no_core, lang_items, rustc_attrs)]
+#![crate_type = "rlib"]
#![no_core]
#[rustc_builtin_macro]
@@ -14,26 +17,30 @@ macro_rules! asm {
#[lang = "sized"]
trait Sized {}
-fn main() {
+pub fn main() {
unsafe {
asm!(".intel_syntax noprefix", "nop");
- //[x86_64]~^ ERROR intel syntax is the default syntax on this target
+ //[x86_64]~^ WARN avoid using `.intel_syntax`
+ //[arm]~^^ ERROR unknown directive
asm!(".intel_syntax aaa noprefix", "nop");
- //[x86_64]~^ ERROR intel syntax is the default syntax on this target
+ //[x86_64]~^ WARN avoid using `.intel_syntax`
+ //[arm]~^^ ERROR unknown directive
asm!(".att_syntax noprefix", "nop");
- //[x86_64]~^ ERROR using the .att_syntax directive may cause issues
- //[arm]~^^ att syntax is the default syntax on this target
+ //[x86_64]~^ WARN avoid using `.att_syntax`
+ //[arm]~^^ ERROR unknown directive
asm!(".att_syntax bbb noprefix", "nop");
- //[x86_64]~^ ERROR using the .att_syntax directive may cause issues
- //[arm]~^^ att syntax is the default syntax on this target
+ //[x86_64]~^ WARN avoid using `.att_syntax`
+ //[arm]~^^ ERROR unknown directive
asm!(".intel_syntax noprefix; nop");
- //[x86_64]~^ ERROR intel syntax is the default syntax on this target
+ //[x86_64]~^ WARN avoid using `.intel_syntax`
+ //[arm]~^^ ERROR unknown directive
asm!(
r"
.intel_syntax noprefix
nop"
);
- //[x86_64]~^^^ ERROR intel syntax is the default syntax on this target
+ //[x86_64]~^^^ WARN avoid using `.intel_syntax`
+ //[arm]~^^^^ ERROR unknown directive
}
}
diff --git a/src/test/ui/asm/inline-syntax.x86_64.stderr b/src/test/ui/asm/inline-syntax.x86_64.stderr
index 826657c98e1..5c03d3a002c 100644
--- a/src/test/ui/asm/inline-syntax.x86_64.stderr
+++ b/src/test/ui/asm/inline-syntax.x86_64.stderr
@@ -1,50 +1,40 @@
-error: intel syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:19:15
+warning: avoid using `.intel_syntax`, Intel syntax is the default
+ --> $DIR/inline-syntax.rs:22:15
|
LL | asm!(".intel_syntax noprefix", "nop");
- | ^^^^^^^^^^^^^^^^^^^^^^ help: remove this assembler directive
+ | ^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: `#[warn(bad_asm_style)]` on by default
-error: intel syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:21:15
+warning: avoid using `.intel_syntax`, Intel syntax is the default
+ --> $DIR/inline-syntax.rs:25:15
|
LL | asm!(".intel_syntax aaa noprefix", "nop");
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this assembler directive
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-error: using the .att_syntax directive may cause issues, use the att_syntax option instead
- --> $DIR/inline-syntax.rs:23:15
+warning: avoid using `.att_syntax`, prefer using `options(att_syntax)` instead
+ --> $DIR/inline-syntax.rs:28:15
|
LL | asm!(".att_syntax noprefix", "nop");
| ^^^^^^^^^^^^^^^^^^^^
- |
-help: remove the assembler directive and replace it with options(att_syntax)
- |
-LL | asm!("", "nop", options(att_syntax));
- | -- ^^^^^^^^^^^^^^^^^^^^^
-error: using the .att_syntax directive may cause issues, use the att_syntax option instead
- --> $DIR/inline-syntax.rs:26:15
+warning: avoid using `.att_syntax`, prefer using `options(att_syntax)` instead
+ --> $DIR/inline-syntax.rs:31:15
|
LL | asm!(".att_syntax bbb noprefix", "nop");
| ^^^^^^^^^^^^^^^^^^^^^^^^
- |
-help: remove the assembler directive and replace it with options(att_syntax)
- |
-LL | asm!("", "nop", options(att_syntax));
- | -- ^^^^^^^^^^^^^^^^^^^^^
-error: intel syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:29:15
+warning: avoid using `.intel_syntax`, Intel syntax is the default
+ --> $DIR/inline-syntax.rs:34:15
|
LL | asm!(".intel_syntax noprefix; nop");
- | ^^^^^^^^^^^^^^^^^^^^^^ help: remove this assembler directive
+ | ^^^^^^^^^^^^^^^^^^^^^^
-error: intel syntax is the default syntax on this target, and trying to use this directive may cause issues
- --> $DIR/inline-syntax.rs:34:14
+warning: avoid using `.intel_syntax`, Intel syntax is the default
+ --> $DIR/inline-syntax.rs:40:13
|
-LL | .intel_syntax noprefix
- | ______________^
-LL | | nop"
- | |_ help: remove this assembler directive
+LL | .intel_syntax noprefix
+ | ^^^^^^^^^^^^^^^^^^^^^^
-error: aborting due to 6 previous errors
+warning: 6 warnings emitted