From 691206470b0a48fa89a8742bba21bf1034a44b54 Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Mon, 25 Aug 2025 08:48:39 +0000 Subject: [PATCH 1/2] rustc_codegen_ssa: Fix comment --- compiler/rustc_codegen_ssa/src/back/metadata.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs index bf38c02e908e4..55cbf81a8bbbc 100644 --- a/compiler/rustc_codegen_ssa/src/back/metadata.rs +++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs @@ -329,7 +329,7 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 { // Source: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/079772828bd10933d34121117a222b4cc0ee2200/riscv-elf.adoc let mut e_flags: u32 = 0x0; - // Check if compressed is enabled + // Check if compression is enabled // `unstable_target_features` is used here because "c" is gated behind riscv_target_feature. if sess.unstable_target_features.contains(&sym::c) { e_flags |= elf::EF_RISCV_RVC; From cb8c905c47aea018d8bef7b68ab885ce99d984da Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Mon, 25 Aug 2025 08:48:39 +0000 Subject: [PATCH 2/2] rustc_codegen_ssa: More comprehensive RISC-V ELF flags This commit implements more conformant, more comprehensive RISC-V ELF flags handling when generating certain object files directly from rustc. * Use "zca" instead of "c" The "Zca" extension (a subset of "C") is the minimal configuration for compressed instructions to set `EF_RISCV_RVC` flag. * Set TSO flag from "ztso" The "Ztso" extension denotes that the program depends on the RVTSO (Total Store Ordering) memory consistency model, which is stronger than the standard RVWMO (Weak Memory Ordering) consistency model and on ELF targets, we need to set `EF_RISCV_TSO` flag. --- compiler/rustc_codegen_ssa/src/back/metadata.rs | 10 ++++++++-- compiler/rustc_span/src/symbol.rs | 2 ++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs index 55cbf81a8bbbc..10aaadd5688a3 100644 --- a/compiler/rustc_codegen_ssa/src/back/metadata.rs +++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs @@ -330,11 +330,17 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 { let mut e_flags: u32 = 0x0; // Check if compression is enabled - // `unstable_target_features` is used here because "c" is gated behind riscv_target_feature. - if sess.unstable_target_features.contains(&sym::c) { + // `unstable_target_features` is used here because "zca" is gated behind riscv_target_feature. + if sess.unstable_target_features.contains(&sym::zca) { e_flags |= elf::EF_RISCV_RVC; } + // Check if RVTSO is enabled + // `unstable_target_features` is used here because "ztso" is gated behind riscv_target_feature. + if sess.unstable_target_features.contains(&sym::ztso) { + e_flags |= elf::EF_RISCV_TSO; + } + // Set the appropriate flag based on ABI // This needs to match LLVM `RISCVELFStreamer.cpp` match &*sess.target.llvm_abiname { diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 5d140cc611771..585968044bf24 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -2419,9 +2419,11 @@ symbols! { yield_expr, ymm_reg, yreg, + zca, zfh, zfhmin, zmm_reg, + ztso, // tidy-alphabetical-end } }