From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- rust/syn/op.rs | 221 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 221 insertions(+) create mode 100644 rust/syn/op.rs (limited to 'rust/syn/op.rs') diff --git a/rust/syn/op.rs b/rust/syn/op.rs new file mode 100644 index 000000000..73dada3fa --- /dev/null +++ b/rust/syn/op.rs @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +ast_enum! { + /// A binary operator: `+`, `+=`, `&`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + #[non_exhaustive] + pub enum BinOp { + /// The `+` operator (addition) + Add(Token![+]), + /// The `-` operator (subtraction) + Sub(Token![-]), + /// The `*` operator (multiplication) + Mul(Token![*]), + /// The `/` operator (division) + Div(Token![/]), + /// The `%` operator (modulus) + Rem(Token![%]), + /// The `&&` operator (logical and) + And(Token![&&]), + /// The `||` operator (logical or) + Or(Token![||]), + /// The `^` operator (bitwise xor) + BitXor(Token![^]), + /// The `&` operator (bitwise and) + BitAnd(Token![&]), + /// The `|` operator (bitwise or) + BitOr(Token![|]), + /// The `<<` operator (shift left) + Shl(Token![<<]), + /// The `>>` operator (shift right) + Shr(Token![>>]), + /// The `==` operator (equality) + Eq(Token![==]), + /// The `<` operator (less than) + Lt(Token![<]), + /// The `<=` operator (less than or equal to) + Le(Token![<=]), + /// The `!=` operator (not equal to) + Ne(Token![!=]), + /// The `>=` operator (greater than or equal to) + Ge(Token![>=]), + /// The `>` operator (greater than) + Gt(Token![>]), + /// The `+=` operator + AddAssign(Token![+=]), + /// The `-=` operator + SubAssign(Token![-=]), + /// The `*=` operator + MulAssign(Token![*=]), + /// The `/=` operator + DivAssign(Token![/=]), + /// The `%=` operator + RemAssign(Token![%=]), + /// The `^=` operator + BitXorAssign(Token![^=]), + /// The `&=` operator + BitAndAssign(Token![&=]), + /// The `|=` operator + BitOrAssign(Token![|=]), + /// The `<<=` operator + ShlAssign(Token![<<=]), + /// The `>>=` operator + ShrAssign(Token![>>=]), + } +} + +ast_enum! { + /// A unary operator: `*`, `!`, `-`. + #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))] + #[non_exhaustive] + pub enum UnOp { + /// The `*` operator for dereferencing + Deref(Token![*]), + /// The `!` operator for logical inversion + Not(Token![!]), + /// The `-` operator for negation + Neg(Token![-]), + } +} + +#[cfg(feature = "parsing")] +pub(crate) mod parsing { + use crate::error::Result; + use crate::op::{BinOp, UnOp}; + use crate::parse::{Parse, ParseStream}; + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for BinOp { + fn parse(input: ParseStream) -> Result { + if input.peek(Token![+=]) { + input.parse().map(BinOp::AddAssign) + } else if input.peek(Token![-=]) { + input.parse().map(BinOp::SubAssign) + } else if input.peek(Token![*=]) { + input.parse().map(BinOp::MulAssign) + } else if input.peek(Token![/=]) { + input.parse().map(BinOp::DivAssign) + } else if input.peek(Token![%=]) { + input.parse().map(BinOp::RemAssign) + } else if input.peek(Token![^=]) { + input.parse().map(BinOp::BitXorAssign) + } else if input.peek(Token![&=]) { + input.parse().map(BinOp::BitAndAssign) + } else if input.peek(Token![|=]) { + input.parse().map(BinOp::BitOrAssign) + } else if input.peek(Token![<<=]) { + input.parse().map(BinOp::ShlAssign) + } else if input.peek(Token![>>=]) { + input.parse().map(BinOp::ShrAssign) + } else if input.peek(Token![&&]) { + input.parse().map(BinOp::And) + } else if input.peek(Token![||]) { + input.parse().map(BinOp::Or) + } else if input.peek(Token![<<]) { + input.parse().map(BinOp::Shl) + } else if input.peek(Token![>>]) { + input.parse().map(BinOp::Shr) + } else if input.peek(Token![==]) { + input.parse().map(BinOp::Eq) + } else if input.peek(Token![<=]) { + input.parse().map(BinOp::Le) + } else if input.peek(Token![!=]) { + input.parse().map(BinOp::Ne) + } else if input.peek(Token![>=]) { + input.parse().map(BinOp::Ge) + } else if input.peek(Token![+]) { + input.parse().map(BinOp::Add) + } else if input.peek(Token![-]) { + input.parse().map(BinOp::Sub) + } else if input.peek(Token![*]) { + input.parse().map(BinOp::Mul) + } else if input.peek(Token![/]) { + input.parse().map(BinOp::Div) + } else if input.peek(Token![%]) { + input.parse().map(BinOp::Rem) + } else if input.peek(Token![^]) { + input.parse().map(BinOp::BitXor) + } else if input.peek(Token![&]) { + input.parse().map(BinOp::BitAnd) + } else if input.peek(Token![|]) { + input.parse().map(BinOp::BitOr) + } else if input.peek(Token![<]) { + input.parse().map(BinOp::Lt) + } else if input.peek(Token![>]) { + input.parse().map(BinOp::Gt) + } else { + Err(input.error("expected binary operator")) + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for UnOp { + fn parse(input: ParseStream) -> Result { + let lookahead = input.lookahead1(); + if lookahead.peek(Token![*]) { + input.parse().map(UnOp::Deref) + } else if lookahead.peek(Token![!]) { + input.parse().map(UnOp::Not) + } else if lookahead.peek(Token![-]) { + input.parse().map(UnOp::Neg) + } else { + Err(lookahead.error()) + } + } + } +} + +#[cfg(feature = "printing")] +mod printing { + use crate::op::{BinOp, UnOp}; + use proc_macro2::TokenStream; + use quote::ToTokens; + + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for BinOp { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + BinOp::Add(t) => t.to_tokens(tokens), + BinOp::Sub(t) => t.to_tokens(tokens), + BinOp::Mul(t) => t.to_tokens(tokens), + BinOp::Div(t) => t.to_tokens(tokens), + BinOp::Rem(t) => t.to_tokens(tokens), + BinOp::And(t) => t.to_tokens(tokens), + BinOp::Or(t) => t.to_tokens(tokens), + BinOp::BitXor(t) => t.to_tokens(tokens), + BinOp::BitAnd(t) => t.to_tokens(tokens), + BinOp::BitOr(t) => t.to_tokens(tokens), + BinOp::Shl(t) => t.to_tokens(tokens), + BinOp::Shr(t) => t.to_tokens(tokens), + BinOp::Eq(t) => t.to_tokens(tokens), + BinOp::Lt(t) => t.to_tokens(tokens), + BinOp::Le(t) => t.to_tokens(tokens), + BinOp::Ne(t) => t.to_tokens(tokens), + BinOp::Ge(t) => t.to_tokens(tokens), + BinOp::Gt(t) => t.to_tokens(tokens), + BinOp::AddAssign(t) => t.to_tokens(tokens), + BinOp::SubAssign(t) => t.to_tokens(tokens), + BinOp::MulAssign(t) => t.to_tokens(tokens), + BinOp::DivAssign(t) => t.to_tokens(tokens), + BinOp::RemAssign(t) => t.to_tokens(tokens), + BinOp::BitXorAssign(t) => t.to_tokens(tokens), + BinOp::BitAndAssign(t) => t.to_tokens(tokens), + BinOp::BitOrAssign(t) => t.to_tokens(tokens), + BinOp::ShlAssign(t) => t.to_tokens(tokens), + BinOp::ShrAssign(t) => t.to_tokens(tokens), + } + } + } + + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for UnOp { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + UnOp::Deref(t) => t.to_tokens(tokens), + UnOp::Not(t) => t.to_tokens(tokens), + UnOp::Neg(t) => t.to_tokens(tokens), + } + } + } +} -- cgit v1.3.1