From 73f8309300bce03e62c8a49e8a06b884175b5f88 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Fri, 11 Oct 2024 00:26:21 +0100 Subject: Support use of asm goto with outputs and `options(noreturn)` When labels are present, the `noreturn` option really means that asm block won't fallthrough -- if labels are present, then outputs can still be meaningfully used. --- compiler/rustc_codegen_llvm/src/asm.rs | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'compiler/rustc_codegen_llvm/src') diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs index 2455d13df8d..07473190d6f 100644 --- a/compiler/rustc_codegen_llvm/src/asm.rs +++ b/compiler/rustc_codegen_llvm/src/asm.rs @@ -343,7 +343,14 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> { attributes::apply_to_callsite(result, llvm::AttributePlace::Function, &{ attrs }); // Write results to outputs. We need to do this for all possible control flow. - for block in Some(dest).into_iter().chain(labels.iter().copied().map(Some)) { + // + // 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); } -- cgit 1.4.1-3-g733a5