Auto merge of #6092 - jethrogb:jb/inline-asm-syntax-lint, r=ebroto

Add lint for inline assembly syntax style preference

changelog: Add lint for inline assembly syntax style preference

6 files changed, 223 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 575cbd60792..0de6f4b4235 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1635,6 +1635,8 @@ Released 2018-09-13
 [`inherent_to_string`]: https://rust-lang.github.io/rust-clippy/master/index.html#inherent_to_string
 [`inherent_to_string_shadow_display`]: https://rust-lang.github.io/rust-clippy/master/index.html#inherent_to_string_shadow_display
 [`inline_always`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_always
+[`inline_asm_x86_att_syntax`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_asm_x86_att_syntax
+[`inline_asm_x86_intel_syntax`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_asm_x86_intel_syntax
 [`inline_fn_without_body`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_fn_without_body
 [`int_plus_one`]: https://rust-lang.github.io/rust-clippy/master/index.html#int_plus_one
 [`integer_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_arithmetic
diff --git a/clippy_lints/src/asm_syntax.rs b/clippy_lints/src/asm_syntax.rs
new file mode 100644
index 00000000000..ef1f1a14afc
--- /dev/null
+++ b/clippy_lints/src/asm_syntax.rs
@@ -0,0 +1,125 @@
+use std::fmt;
+
+use crate::utils::span_lint_and_help;
+use rustc_ast::ast::{Expr, ExprKind, InlineAsmOptions};
+use rustc_lint::{EarlyContext, EarlyLintPass, Lint};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum AsmStyle {
+    Intel,
+    Att,
+}
+
+impl fmt::Display for AsmStyle {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            AsmStyle::Intel => f.write_str("Intel"),
+            AsmStyle::Att => f.write_str("AT&T"),
+        }
+    }
+}
+
+impl std::ops::Not for AsmStyle {
+    type Output = AsmStyle;
+
+    fn not(self) -> AsmStyle {
+        match self {
+            AsmStyle::Intel => AsmStyle::Att,
+            AsmStyle::Att => AsmStyle::Intel,
+        }
+    }
+}
+
+fn check_expr_asm_syntax(lint: &'static Lint, cx: &EarlyContext<'_>, expr: &Expr, check_for: AsmStyle) {
+    if let ExprKind::InlineAsm(ref inline_asm) = expr.kind {
+        let style = if inline_asm.options.contains(InlineAsmOptions::ATT_SYNTAX) {
+            AsmStyle::Att
+        } else {
+            AsmStyle::Intel
+        };
+
+        if style == check_for {
+            span_lint_and_help(
+                cx,
+                lint,
+                expr.span,
+                &format!("{} x86 assembly syntax used", style),
+                None,
+                &format!("use {} x86 assembly syntax", !style),
+            );
+        }
+    }
+}
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for usage of Intel x86 assembly syntax.
+    ///
+    /// **Why is this bad?** The lint has been enabled to indicate a preference
+    /// for AT&T x86 assembly syntax.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust,no_run
+    /// # #![feature(asm)]
+    /// # unsafe { let ptr = "".as_ptr();
+    /// asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
+    /// # }
+    /// ```
+    /// Use instead:
+    /// ```rust,no_run
+    /// # #![feature(asm)]
+    /// # unsafe { let ptr = "".as_ptr();
+    /// asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
+    /// # }
+    /// ```
+    pub INLINE_ASM_X86_INTEL_SYNTAX,
+    restriction,
+    "prefer AT&T x86 assembly syntax"
+}
+
+declare_lint_pass!(InlineAsmX86IntelSyntax => [INLINE_ASM_X86_INTEL_SYNTAX]);
+
+impl EarlyLintPass for InlineAsmX86IntelSyntax {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+        check_expr_asm_syntax(Self::get_lints()[0], cx, expr, AsmStyle::Intel);
+    }
+}
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for usage of AT&T x86 assembly syntax.
+    ///
+    /// **Why is this bad?** The lint has been enabled to indicate a preference
+    /// for Intel x86 assembly syntax.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust,no_run
+    /// # #![feature(asm)]
+    /// # unsafe { let ptr = "".as_ptr();
+    /// asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
+    /// # }
+    /// ```
+    /// Use instead:
+    /// ```rust,no_run
+    /// # #![feature(asm)]
+    /// # unsafe { let ptr = "".as_ptr();
+    /// asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
+    /// # }
+    /// ```
+    pub INLINE_ASM_X86_ATT_SYNTAX,
+    restriction,
+    "prefer Intel x86 assembly syntax"
+}
+
+declare_lint_pass!(InlineAsmX86AttSyntax => [INLINE_ASM_X86_ATT_SYNTAX]);
+
+impl EarlyLintPass for InlineAsmX86AttSyntax {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+        check_expr_asm_syntax(Self::get_lints()[0], cx, expr, AsmStyle::Att);
+    }
+}
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index 529c2450541..10da59c7a7a 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -153,6 +153,7 @@ mod utils;
 mod approx_const;
 mod arithmetic;
 mod as_conversions;
+mod asm_syntax;
 mod assertions_on_constants;
 mod assign_ops;
 mod async_yields_async;
@@ -487,6 +488,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &arithmetic::FLOAT_ARITHMETIC,
         &arithmetic::INTEGER_ARITHMETIC,
         &as_conversions::AS_CONVERSIONS,
+        &asm_syntax::INLINE_ASM_X86_ATT_SYNTAX,
+        &asm_syntax::INLINE_ASM_X86_INTEL_SYNTAX,
         &assertions_on_constants::ASSERTIONS_ON_CONSTANTS,
         &assign_ops::ASSIGN_OP_PATTERN,
         &assign_ops::MISREFACTORED_ASSIGN_OP,
@@ -1123,12 +1126,16 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| box utils::internal_lints::MatchTypeOnDiagItem);
     let disallowed_methods = conf.disallowed_methods.iter().cloned().collect::<FxHashSet<_>>();
     store.register_late_pass(move || box disallowed_method::DisallowedMethod::new(&disallowed_methods));
+    store.register_early_pass(|| box asm_syntax::InlineAsmX86AttSyntax);
+    store.register_early_pass(|| box asm_syntax::InlineAsmX86IntelSyntax);
 
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
         LintId::of(&arithmetic::INTEGER_ARITHMETIC),
         LintId::of(&as_conversions::AS_CONVERSIONS),
+        LintId::of(&asm_syntax::INLINE_ASM_X86_ATT_SYNTAX),
+        LintId::of(&asm_syntax::INLINE_ASM_X86_INTEL_SYNTAX),
         LintId::of(&create_dir::CREATE_DIR),
         LintId::of(&dbg_macro::DBG_MACRO),
         LintId::of(&else_if_without_else::ELSE_IF_WITHOUT_ELSE),
diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs
index 76e655ad603..16ceb617965 100644
--- a/src/lintlist/mod.rs
+++ b/src/lintlist/mod.rs
@@ -900,6 +900,20 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
         module: "attrs",
     },
     Lint {
+        name: "inline_asm_x86_att_syntax",
+        group: "restriction",
+        desc: "prefer Intel x86 assembly syntax",
+        deprecation: None,
+        module: "asm_syntax",
+    },
+    Lint {
+        name: "inline_asm_x86_intel_syntax",
+        group: "restriction",
+        desc: "prefer AT&T x86 assembly syntax",
+        deprecation: None,
+        module: "asm_syntax",
+    },
+    Lint {
         name: "inline_fn_without_body",
         group: "correctness",
         desc: "use of `#[inline]` on trait methods without bodies",
diff --git a/tests/ui/asm_syntax.rs b/tests/ui/asm_syntax.rs
new file mode 100644
index 00000000000..658cae397e1
--- /dev/null
+++ b/tests/ui/asm_syntax.rs
@@ -0,0 +1,31 @@
+#![feature(asm)]
+// only-x86_64
+
+#[warn(clippy::inline_asm_x86_intel_syntax)]
+mod warn_intel {
+    pub(super) unsafe fn use_asm() {
+        asm!("");
+        asm!("", options());
+        asm!("", options(nostack));
+        asm!("", options(att_syntax));
+        asm!("", options(nostack, att_syntax));
+    }
+}
+
+#[warn(clippy::inline_asm_x86_att_syntax)]
+mod warn_att {
+    pub(super) unsafe fn use_asm() {
+        asm!("");
+        asm!("", options());
+        asm!("", options(nostack));
+        asm!("", options(att_syntax));
+        asm!("", options(nostack, att_syntax));
+    }
+}
+
+fn main() {
+    unsafe {
+        warn_att::use_asm();
+        warn_intel::use_asm();
+    }
+}
diff --git a/tests/ui/asm_syntax.stderr b/tests/ui/asm_syntax.stderr
new file mode 100644
index 00000000000..27b51166eac
--- /dev/null
+++ b/tests/ui/asm_syntax.stderr
@@ -0,0 +1,44 @@
+error: Intel x86 assembly syntax used
+  --> $DIR/asm_syntax.rs:7:9
+   |
+LL |         asm!("");
+   |         ^^^^^^^^^
+   |
+   = note: `-D clippy::inline-asm-x86-intel-syntax` implied by `-D warnings`
+   = help: use AT&T x86 assembly syntax
+
+error: Intel x86 assembly syntax used
+  --> $DIR/asm_syntax.rs:8:9
+   |
+LL |         asm!("", options());
+   |         ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use AT&T x86 assembly syntax
+
+error: Intel x86 assembly syntax used
+  --> $DIR/asm_syntax.rs:9:9
+   |
+LL |         asm!("", options(nostack));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use AT&T x86 assembly syntax
+
+error: AT&T x86 assembly syntax used
+  --> $DIR/asm_syntax.rs:21:9
+   |
+LL |         asm!("", options(att_syntax));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::inline-asm-x86-att-syntax` implied by `-D warnings`
+   = help: use Intel x86 assembly syntax
+
+error: AT&T x86 assembly syntax used
+  --> $DIR/asm_syntax.rs:22:9
+   |
+LL |         asm!("", options(nostack, att_syntax));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use Intel x86 assembly syntax
+
+error: aborting due to 5 previous errors
+