diff options
| -rw-r--r-- | compiler/rustc_ast_lowering/messages.ftl | 2 | ||||
| -rw-r--r-- | compiler/rustc_ast_lowering/src/asm.rs | 44 | ||||
| -rw-r--r-- | compiler/rustc_builtin_macros/src/asm.rs | 5 | ||||
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/asm.rs | 42 | ||||
| -rw-r--r-- | compiler/rustc_feature/src/unstable.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_span/src/symbol.rs | 1 | ||||
| -rw-r--r-- | tests/codegen/asm/goto.rs | 38 | ||||
| -rw-r--r-- | tests/ui/asm/x86_64/goto.rs | 64 | ||||
| -rw-r--r-- | tests/ui/asm/x86_64/goto.stderr | 4 | ||||
| -rw-r--r-- | tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.rs | 13 | ||||
| -rw-r--r-- | tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.stderr | 13 |
11 files changed, 178 insertions, 50 deletions
diff --git a/compiler/rustc_ast_lowering/messages.ftl b/compiler/rustc_ast_lowering/messages.ftl index f704320c71d..93e1e25384e 100644 --- a/compiler/rustc_ast_lowering/messages.ftl +++ b/compiler/rustc_ast_lowering/messages.ftl @@ -181,6 +181,8 @@ ast_lowering_underscore_expr_lhs_assign = .label = `_` not allowed here ast_lowering_unstable_inline_assembly = inline assembly is not stable yet on this architecture +ast_lowering_unstable_inline_assembly_label_operand_with_outputs = + using both label and output operands for inline assembly is unstable ast_lowering_unstable_inline_assembly_label_operands = label operands for inline assembly are unstable ast_lowering_unstable_may_unwind = the `may_unwind` option is unstable diff --git a/compiler/rustc_ast_lowering/src/asm.rs b/compiler/rustc_ast_lowering/src/asm.rs index 215e6d84d0f..520274278a1 100644 --- a/compiler/rustc_ast_lowering/src/asm.rs +++ b/compiler/rustc_ast_lowering/src/asm.rs @@ -239,15 +239,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } } InlineAsmOperand::Label { block } => { - if !self.tcx.features().asm_goto() { - feature_err( - sess, - sym::asm_goto, - *op_sp, - fluent::ast_lowering_unstable_inline_assembly_label_operands, - ) - .emit(); - } hir::InlineAsmOperand::Label { block: self.lower_block(block, false) } } }; @@ -466,6 +457,41 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } } + // Feature gate checking for asm goto. + if let Some((_, op_sp)) = + operands.iter().find(|(op, _)| matches!(op, hir::InlineAsmOperand::Label { .. })) + { + if !self.tcx.features().asm_goto() { + feature_err( + sess, + sym::asm_goto, + *op_sp, + fluent::ast_lowering_unstable_inline_assembly_label_operands, + ) + .emit(); + } + + // In addition, check if an output operand is used. + // This is gated behind an additional feature. + let output_operand_used = operands.iter().any(|(op, _)| { + matches!( + op, + hir::InlineAsmOperand::Out { expr: Some(_), .. } + | hir::InlineAsmOperand::InOut { .. } + | hir::InlineAsmOperand::SplitInOut { out_expr: Some(_), .. } + ) + }); + if output_operand_used && !self.tcx.features().asm_goto_with_outputs() { + feature_err( + sess, + sym::asm_goto_with_outputs, + *op_sp, + fluent::ast_lowering_unstable_inline_assembly_label_operand_with_outputs, + ) + .emit(); + } + } + let operands = self.arena.alloc_from_iter(operands); let template = self.arena.alloc_from_iter(asm.template.iter().cloned()); let template_strs = self.arena.alloc_from_iter( diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs index 9ae48024f44..14ac3cd74e8 100644 --- a/compiler/rustc_builtin_macros/src/asm.rs +++ b/compiler/rustc_builtin_macros/src/asm.rs @@ -300,7 +300,10 @@ pub fn parse_asm_args<'a>( if args.options.contains(ast::InlineAsmOptions::PURE) && !have_real_output { dcx.emit_err(errors::AsmPureNoOutput { spans: args.options_spans.clone() }); } - if args.options.contains(ast::InlineAsmOptions::NORETURN) && !outputs_sp.is_empty() { + if args.options.contains(ast::InlineAsmOptions::NORETURN) + && !outputs_sp.is_empty() + && labels_sp.is_empty() + { let err = dcx.create_err(errors::AsmNoReturn { outputs_sp }); // Bail out now since this is likely to confuse MIR return Err(err); diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs index bb74dfe1487..07473190d6f 100644 --- a/compiler/rustc_codegen_llvm/src/asm.rs +++ b/compiler/rustc_codegen_llvm/src/asm.rs @@ -342,24 +342,32 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> { } attributes::apply_to_callsite(result, llvm::AttributePlace::Function, &{ attrs }); - // Switch to the 'normal' basic block if we did an `invoke` instead of a `call` - if let Some(dest) = dest { - self.switch_to_block(dest); - } + // Write results to outputs. We need to do this for all possible control flow. + // + // Note that `dest` maybe populated with unreachable_block when asm goto with outputs + // is used (because we need to codegen callbr which always needs a destination), so + // here we use the NORETURN option to determine if `dest` should be used. + for block in (if options.contains(InlineAsmOptions::NORETURN) { None } else { Some(dest) }) + .into_iter() + .chain(labels.iter().copied().map(Some)) + { + if let Some(block) = block { + self.switch_to_block(block); + } - // Write results to outputs - for (idx, op) in operands.iter().enumerate() { - if let InlineAsmOperandRef::Out { reg, place: Some(place), .. } - | InlineAsmOperandRef::InOut { reg, out_place: Some(place), .. } = *op - { - let value = if output_types.len() == 1 { - result - } else { - self.extract_value(result, op_idx[&idx] as u64) - }; - let value = - llvm_fixup_output(self, value, reg.reg_class(), &place.layout, instance); - OperandValue::Immediate(value).store(self, place); + for (idx, op) in operands.iter().enumerate() { + if let InlineAsmOperandRef::Out { reg, place: Some(place), .. } + | InlineAsmOperandRef::InOut { reg, out_place: Some(place), .. } = *op + { + let value = if output_types.len() == 1 { + result + } else { + self.extract_value(result, op_idx[&idx] as u64) + }; + let value = + llvm_fixup_output(self, value, reg.reg_class(), &place.layout, instance); + OperandValue::Immediate(value).store(self, place); + } } } } diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index cf0f2a7e48c..6a231397615 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -378,6 +378,8 @@ declare_features! ( (unstable, asm_experimental_arch, "1.58.0", Some(93335)), /// Allows using `label` operands in inline assembly. (unstable, asm_goto, "1.78.0", Some(119364)), + /// Allows using `label` operands in inline assembly together with output operands. + (unstable, asm_goto_with_outputs, "CURRENT_RUSTC_VERSION", Some(119364)), /// Allows the `may_unwind` option in inline assembly. (unstable, asm_unwind, "1.58.0", Some(93334)), /// Allows users to enforce equality of associated constants `TraitImpl<AssocConst=3>`. diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 3d0ec2afa2b..0e4d937d6fd 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -417,6 +417,7 @@ symbols! { asm_const, asm_experimental_arch, asm_goto, + asm_goto_with_outputs, asm_sym, asm_unwind, assert, diff --git a/tests/codegen/asm/goto.rs b/tests/codegen/asm/goto.rs index e522d0da5b4..c40a43fbe1b 100644 --- a/tests/codegen/asm/goto.rs +++ b/tests/codegen/asm/goto.rs @@ -2,21 +2,10 @@ //@ only-x86_64 #![crate_type = "rlib"] -#![feature(asm_goto)] +#![feature(asm_goto, asm_goto_with_outputs)] use std::arch::asm; -#[no_mangle] -pub extern "C" fn panicky() {} - -struct Foo; - -impl Drop for Foo { - fn drop(&mut self) { - println!(); - } -} - // CHECK-LABEL: @asm_goto #[no_mangle] pub unsafe fn asm_goto() { @@ -38,14 +27,37 @@ pub unsafe fn asm_goto_with_outputs() -> u64 { out } +// CHECK-LABEL: @asm_goto_with_outputs_use_in_label +#[no_mangle] +pub unsafe fn asm_goto_with_outputs_use_in_label() -> u64 { + let out: u64; + // CHECK: [[RES:%[0-9]+]] = callbr i64 asm sideeffect alignstack inteldialect " + // CHECK-NEXT: to label %[[FALLTHROUGHBB:[a-b0-9]+]] [label %[[JUMPBB:[a-b0-9]+]]] + asm!("{} /* {} */", out(reg) out, label { return out; }); + // CHECK: [[JUMPBB]]: + // CHECK-NEXT: [[RET:%.+]] = phi i64 [ 1, %[[FALLTHROUGHBB]] ], [ [[RES]], %start ] + // CHECK-NEXT: ret i64 [[RET]] + 1 +} + // CHECK-LABEL: @asm_goto_noreturn #[no_mangle] pub unsafe fn asm_goto_noreturn() -> u64 { - let out: u64; // CHECK: callbr void asm sideeffect alignstack inteldialect " // CHECK-NEXT: to label %unreachable [label %[[JUMPBB:[a-b0-9]+]]] asm!("jmp {}", label { return 1; }, options(noreturn)); // CHECK: [[JUMPBB]]: // CHECK-NEXT: ret i64 1 +} + +// CHECK-LABEL: @asm_goto_noreturn_with_outputs +#[no_mangle] +pub unsafe fn asm_goto_noreturn_with_outputs() -> u64 { + let out: u64; + // CHECK: [[RES:%[0-9]+]] = callbr i64 asm sideeffect alignstack inteldialect " + // CHECK-NEXT: to label %[[FALLTHROUGHBB:[a-b0-9]+]] [label %[[JUMPBB:[a-b0-9]+]]] + asm!("mov {}, 1", "jmp {}", out(reg) out, label { return out; }); + // CHECK: [[JUMPBB]]: + // CHECK-NEXT: ret i64 [[RES]] out } diff --git a/tests/ui/asm/x86_64/goto.rs b/tests/ui/asm/x86_64/goto.rs index 6c14bb57ac6..50e7441509a 100644 --- a/tests/ui/asm/x86_64/goto.rs +++ b/tests/ui/asm/x86_64/goto.rs @@ -3,7 +3,7 @@ //@ needs-asm-support #![deny(unreachable_code)] -#![feature(asm_goto)] +#![feature(asm_goto, asm_goto_with_outputs)] use std::arch::asm; @@ -31,10 +31,6 @@ fn goto_jump() { } } -// asm goto with outputs cause miscompilation in LLVM. UB can be triggered -// when outputs are used inside the label block when optimisation is enabled. -// See: https://github.com/llvm/llvm-project/issues/74483 -/* fn goto_out_fallthrough() { unsafe { let mut out: usize; @@ -68,7 +64,57 @@ fn goto_out_jump() { assert!(value); } } -*/ + +fn goto_out_jump_noreturn() { + unsafe { + let mut value = false; + let mut out: usize; + asm!( + "lea {}, [{} + 1]", + "jmp {}", + out(reg) out, + in(reg) 0x12345678usize, + label { + value = true; + assert_eq!(out, 0x12345679); + }, + options(noreturn) + ); + assert!(value); + } +} + +// asm goto with outputs cause miscompilation in LLVM when multiple outputs are present. +// The code sample below is adapted from https://github.com/llvm/llvm-project/issues/74483 +// and does not work with `-C opt-level=0` +#[expect(unused)] +fn goto_multi_out() { + #[inline(never)] + #[allow(unused)] + fn goto_multi_out(a: usize, b: usize) -> usize { + let mut x: usize; + let mut y: usize; + let mut z: usize; + unsafe { + core::arch::asm!( + "mov {x}, {a}", + "test {a}, {a}", + "jnz {label1}", + "/* {y} {z} {b} {label2} */", + x = out(reg) x, + y = out(reg) y, + z = out(reg) z, + a = in(reg) a, + b = in(reg) b, + label1 = label { return x }, + label2 = label { return 1 }, + ); + 0 + } + } + + assert_eq!(goto_multi_out(11, 22), 11); +} fn goto_noreturn() { unsafe { @@ -102,8 +148,10 @@ fn goto_noreturn_diverge() { fn main() { goto_fallthough(); goto_jump(); - // goto_out_fallthrough(); - // goto_out_jump(); + goto_out_fallthrough(); + goto_out_jump(); + goto_out_jump_noreturn(); + // goto_multi_out(); goto_noreturn(); goto_noreturn_diverge(); } diff --git a/tests/ui/asm/x86_64/goto.stderr b/tests/ui/asm/x86_64/goto.stderr index 27e227d71a5..8f89e2b1290 100644 --- a/tests/ui/asm/x86_64/goto.stderr +++ b/tests/ui/asm/x86_64/goto.stderr @@ -1,5 +1,5 @@ warning: unreachable statement - --> $DIR/goto.rs:97:9 + --> $DIR/goto.rs:143:9 | LL | / asm!( LL | | "jmp {}", @@ -13,7 +13,7 @@ LL | unreachable!(); | ^^^^^^^^^^^^^^ unreachable statement | note: the lint level is defined here - --> $DIR/goto.rs:87:8 + --> $DIR/goto.rs:133:8 | LL | #[warn(unreachable_code)] | ^^^^^^^^^^^^^^^^ diff --git a/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.rs b/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.rs new file mode 100644 index 00000000000..294827f78d2 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.rs @@ -0,0 +1,13 @@ +//@ only-x86_64 + +#![feature(asm_goto)] + +use std::arch::asm; + +fn main() { + let mut _out: u64; + unsafe { + asm!("mov {}, 1", "jmp {}", out(reg) _out, label {}); + //~^ ERROR using both label and output operands for inline assembly is unstable + } +} diff --git a/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.stderr b/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.stderr new file mode 100644 index 00000000000..ff7a7d5760a --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-asm_goto_with_outputs.stderr @@ -0,0 +1,13 @@ +error[E0658]: using both label and output operands for inline assembly is unstable + --> $DIR/feature-gate-asm_goto_with_outputs.rs:10:52 + | +LL | asm!("mov {}, 1", "jmp {}", out(reg) _out, label {}); + | ^^^^^^^^ + | + = note: see issue #119364 <https://github.com/rust-lang/rust/issues/119364> for more information + = help: add `#![feature(asm_goto_with_outputs)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0658`. |