diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs index 70f78c07c65..54a8249b175 100644 --- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs +++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs @@ -2128,7 +2128,13 @@ extern "C" { pub fn LLVMRustHasFeature(T: &TargetMachine, s: *const c_char) -> bool; pub fn LLVMRustPrintTargetCPUs(T: &TargetMachine); - pub fn LLVMRustPrintTargetFeatures(T: &TargetMachine); + pub fn LLVMRustGetTargetFeaturesCount(T: &TargetMachine) -> size_t; + pub fn LLVMRustGetTargetFeature( + T: &TargetMachine, + Index: size_t, + Feature: &mut *const c_char, + Desc: &mut *const c_char, + ); pub fn LLVMRustGetHostCPUName(len: *mut usize) -> *const c_char; pub fn LLVMRustCreateTargetMachine( diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs index e80de2bc902..b44553e4f6d 100644 --- a/compiler/rustc_codegen_llvm/src/llvm_util.rs +++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs @@ -10,6 +10,7 @@ use rustc_span::symbol::Symbol; use rustc_target::spec::{MergeFunctions, PanicStrategy}; use std::ffi::{CStr, CString}; +use std::ptr; use std::slice; use std::str; use std::sync::atomic::{AtomicBool, Ordering}; @@ -192,15 +193,77 @@ pub fn print_passes() { } } +fn llvm_target_features(tm: &llvm::TargetMachine) -> Vec<(&str, &str)> { + let len = unsafe { llvm::LLVMRustGetTargetFeaturesCount(tm) }; + let mut ret = Vec::with_capacity(len); + for i in 0..len { + unsafe { + let mut feature = ptr::null(); + let mut desc = ptr::null(); + llvm::LLVMRustGetTargetFeature(tm, i, &mut feature, &mut desc); + if feature.is_null() || desc.is_null() { + bug!("LLVM returned a `null` target feature string"); + } + let feature = CStr::from_ptr(feature).to_str().unwrap_or_else(|e| { + bug!("LLVM returned a non-utf8 feature string: {}", e); + }); + let desc = CStr::from_ptr(desc).to_str().unwrap_or_else(|e| { + bug!("LLVM returned a non-utf8 feature string: {}", e); + }); + ret.push((feature, desc)); + } + } + ret +} + +fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) { + let mut target_features = llvm_target_features(tm); + let mut rustc_target_features = supported_target_features(sess) + .iter() + .filter_map(|(feature, _gate)| { + let llvm_feature = to_llvm_feature(sess, *feature); + // LLVM asserts that these are sorted. LLVM and Rust both use byte comparison for these strings. + target_features.binary_search_by_key(&llvm_feature, |(f, _d)| *f).ok().map(|index| { + let (_f, desc) = target_features.remove(index); + (*feature, desc) + }) + }) + .collect::>(); + rustc_target_features.extend_from_slice(&[( + "crt-static", + "Enables C Run-time Libraries to be statically linked", + )]); + let max_feature_len = target_features + .iter() + .chain(rustc_target_features.iter()) + .map(|(feature, _desc)| feature.len()) + .max() + .unwrap_or(0); + + println!("Features supported by rustc for this target:"); + for (feature, desc) in &rustc_target_features { + println!(" {1:0$} - {2}.", max_feature_len, feature, desc); + } + println!("\nCode-generation features supported by LLVM for this target:"); + for (feature, desc) in &target_features { + println!(" {1:0$} - {2}.", max_feature_len, feature, desc); + } + if target_features.len() == 0 { + println!(" Target features listing is not supported by this LLVM version."); + } + println!("\nUse +feature to enable a feature, or -feature to disable it."); + println!("For example, rustc -C target-cpu=mycpu -C target-feature=+feature1,-feature2\n"); + println!("Code-generation features cannot be used in cfg or #[target_feature],"); + println!("and may be renamed or removed in a future version of LLVM or rustc.\n"); +} + pub(crate) fn print(req: PrintRequest, sess: &Session) { require_inited(); let tm = create_informational_target_machine(sess); - unsafe { - match req { - PrintRequest::TargetCPUs => llvm::LLVMRustPrintTargetCPUs(tm), - PrintRequest::TargetFeatures => llvm::LLVMRustPrintTargetFeatures(tm), - _ => bug!("rustc_codegen_llvm can't handle print request: {:?}", req), - } + match req { + PrintRequest::TargetCPUs => unsafe { llvm::LLVMRustPrintTargetCPUs(tm) }, + PrintRequest::TargetFeatures => print_target_features(sess, tm), + _ => bug!("rustc_codegen_llvm can't handle print request: {:?}", req), } } diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp index b8d5b50dcb5..617b2ed970e 100644 --- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp +++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp @@ -404,26 +404,21 @@ extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM) { printf("\n"); } -extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef TM) { +extern "C" size_t LLVMRustGetTargetFeaturesCount(LLVMTargetMachineRef TM) { const TargetMachine *Target = unwrap(TM); const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo(); const ArrayRef FeatTable = MCInfo->getFeatureTable(); - unsigned MaxFeatLen = getLongestEntryLength(FeatTable); + return FeatTable.size(); +} - printf("Available features for this target:\n"); - for (auto &Feature : FeatTable) - printf(" %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc); - printf("\nRust-specific features:\n"); - printf(" %-*s - %s.\n", - MaxFeatLen, - "crt-static", - "Enables libraries with C Run-time Libraries(CRT) to be statically linked" - ); - printf("\n"); - - printf("Use +feature to enable a feature, or -feature to disable it.\n" - "For example, rustc -C -target-cpu=mycpu -C " - "target-feature=+feature1,-feature2\n\n"); +extern "C" void LLVMRustGetTargetFeature(LLVMTargetMachineRef TM, size_t Index, + const char** Feature, const char** Desc) { + const TargetMachine *Target = unwrap(TM); + const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo(); + const ArrayRef FeatTable = MCInfo->getFeatureTable(); + const SubtargetFeatureKV Feat = FeatTable[Index]; + *Feature = Feat.Key; + *Desc = Feat.Desc; } #else @@ -432,9 +427,11 @@ extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef) { printf("Target CPU help is not supported by this LLVM version.\n\n"); } -extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef) { - printf("Target features help is not supported by this LLVM version.\n\n"); +extern "C" size_t LLVMRustGetTargetFeaturesCount(LLVMTargetMachineRef) { + return 0; } + +extern "C" void LLVMRustGetTargetFeature(LLVMTargetMachineRef, const char**, const char**) {} #endif extern "C" const char* LLVMRustGetHostCPUName(size_t *len) {