diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs index a043660ea632b..3ce550b994074 100644 --- a/compiler/rustc_codegen_gcc/src/context.rs +++ b/compiler/rustc_codegen_gcc/src/context.rs @@ -569,5 +569,6 @@ fn to_gcc_tls_mode(tls_model: TlsModel) -> gccjit::TlsModel { TlsModel::LocalDynamic => gccjit::TlsModel::LocalDynamic, TlsModel::InitialExec => gccjit::TlsModel::InitialExec, TlsModel::LocalExec => gccjit::TlsModel::LocalExec, + TlsModel::EmulatedTls => gccjit::TlsModel::GlobalDynamic, } } diff --git a/compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs b/compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs index 36484c3c3fc44..28a88dd2efea0 100644 --- a/compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs +++ b/compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs @@ -39,7 +39,7 @@ impl OwnedTargetMachine { split_dwarf_file: &CStr, output_obj_file: &CStr, debug_info_compression: &CStr, - force_emulated_tls: bool, + use_emulated_tls: bool, args_cstr_buff: &[u8], ) -> Result> { assert!(args_cstr_buff.len() > 0); @@ -71,7 +71,7 @@ impl OwnedTargetMachine { split_dwarf_file.as_ptr(), output_obj_file.as_ptr(), debug_info_compression.as_ptr(), - force_emulated_tls, + use_emulated_tls, args_cstr_buff.as_ptr() as *const c_char, args_cstr_buff.len(), ) diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs index 3a8b8e1ad1126..baba1e09344e9 100644 --- a/compiler/rustc_codegen_llvm/src/back/write.rs +++ b/compiler/rustc_codegen_llvm/src/back/write.rs @@ -33,7 +33,7 @@ use rustc_session::config::{self, Lto, OutputType, Passes, SplitDwarfKind, Switc use rustc_session::Session; use rustc_span::symbol::sym; use rustc_span::InnerSpan; -use rustc_target::spec::{CodeModel, RelocModel, SanitizerSet, SplitDebuginfo}; +use rustc_target::spec::{CodeModel, RelocModel, SanitizerSet, SplitDebuginfo, TlsModel}; use crate::llvm::diagnostic::OptimizationDiagnosticKind; use libc::{c_char, c_int, c_uint, c_void, size_t}; @@ -223,7 +223,7 @@ pub fn target_machine_factory( let path_mapping = sess.source_map().path_mapping().clone(); - let force_emulated_tls = sess.target.force_emulated_tls; + let use_emulated_tls = matches!(sess.tls_model(), TlsModel::EmulatedTls); // copy the exe path, followed by path all into one buffer // null terminating them so we can use them as null terminated strings @@ -297,7 +297,7 @@ pub fn target_machine_factory( &split_dwarf_file, &output_obj_file, &debuginfo_compression, - force_emulated_tls, + use_emulated_tls, &args_cstr_buff, ) }) diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs index 92a8c00510b94..6aa77ccd83996 100644 --- a/compiler/rustc_codegen_llvm/src/context.rs +++ b/compiler/rustc_codegen_llvm/src/context.rs @@ -120,6 +120,7 @@ fn to_llvm_tls_model(tls_model: TlsModel) -> llvm::ThreadLocalMode { TlsModel::LocalDynamic => llvm::ThreadLocalMode::LocalDynamic, TlsModel::InitialExec => llvm::ThreadLocalMode::InitialExec, TlsModel::LocalExec => llvm::ThreadLocalMode::LocalExec, + TlsModel::EmulatedTls => llvm::ThreadLocalMode::GeneralDynamic, } } diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs index f8a0423e9b104..c7389a83a47d4 100644 --- a/compiler/rustc_codegen_llvm/src/lib.rs +++ b/compiler/rustc_codegen_llvm/src/lib.rs @@ -305,7 +305,13 @@ impl CodegenBackend for LlvmCodegenBackend { } PrintKind::TlsModels => { writeln!(out, "Available TLS models:"); - for name in &["global-dynamic", "local-dynamic", "initial-exec", "local-exec"] { + for name in &[ + "global-dynamic", + "local-dynamic", + "initial-exec", + "local-exec", + "emulated-tls", + ] { writeln!(out, " {name}"); } writeln!(out); diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs index bb5f6e27e4d45..eeb57d4d0f4d8 100644 --- a/compiler/rustc_codegen_ssa/src/back/linker.rs +++ b/compiler/rustc_codegen_ssa/src/back/linker.rs @@ -1748,7 +1748,9 @@ fn exported_symbols_for_non_proc_macro(tcx: TyCtxt<'_>, crate_type: CrateType) - let export_threshold = symbol_export::crates_export_threshold(&[crate_type]); for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| { if info.level.is_below_threshold(export_threshold) { - symbols.push(symbol_export::symbol_name_for_instance_in_crate(tcx, symbol, cnum)); + symbols.push(symbol_export::exporting_symbol_name_for_instance_in_crate( + tcx, symbol, cnum, + )); } }); diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs index b12ac881100a6..e476a788eaee8 100644 --- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs +++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs @@ -16,7 +16,7 @@ use rustc_middle::ty::{self, SymbolName, TyCtxt}; use rustc_middle::ty::{GenericArgKind, GenericArgsRef}; use rustc_middle::util::Providers; use rustc_session::config::{CrateType, OomStrategy}; -use rustc_target::spec::SanitizerSet; +use rustc_target::spec::{SanitizerSet, TlsModel}; pub fn threshold(tcx: TyCtxt<'_>) -> SymbolExportLevel { crates_export_threshold(tcx.crate_types()) @@ -608,6 +608,25 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>( format!("{prefix}{undecorated}{suffix}{args_in_bytes}") } +pub fn exporting_symbol_name_for_instance_in_crate<'tcx>( + tcx: TyCtxt<'tcx>, + symbol: ExportedSymbol<'tcx>, + cnum: CrateNum, +) -> String { + let undecorated = symbol_name_for_instance_in_crate(tcx, symbol, cnum); + + if matches!(tcx.sess.tls_model(), TlsModel::EmulatedTls) + && let ExportedSymbol::NonGeneric(def_id) = symbol + && tcx.is_thread_local_static(def_id) + { + // When using emutls, LLVM will add the `__emutls_v.` prefix to thread local symbols, + // and exported symbol name need to match this. + format!("__emutls_v.{undecorated}") + } else { + undecorated + } +} + fn wasm_import_module_map(tcx: TyCtxt<'_>, cnum: CrateNum) -> FxHashMap { // Build up a map from DefId to a `NativeLib` structure, where // `NativeLib` internally contains information about diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp index 7f03326513697..8085ec532a0e5 100644 --- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp +++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp @@ -410,7 +410,7 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine( const char *SplitDwarfFile, const char *OutputObjFile, const char *DebugInfoCompression, - bool ForceEmulatedTls, + bool UseEmulatedTls, const char *ArgsCstrBuff, size_t ArgsCstrBuffLen) { auto OptLevel = fromRust(RustOptLevel); @@ -456,13 +456,9 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine( Options.UseInitArray = UseInitArray; #if LLVM_VERSION_LT(17, 0) - if (ForceEmulatedTls) { - Options.ExplicitEmulatedTLS = true; - Options.EmulatedTLS = true; - } -#else - Options.EmulatedTLS = ForceEmulatedTls || Trip.hasDefaultEmulatedTLS(); + Options.ExplicitEmulatedTLS = true; #endif + Options.EmulatedTLS = UseEmulatedTls; if (TrapUnreachable) { // Tell LLVM to codegen `unreachable` into an explicit trap instruction. diff --git a/compiler/rustc_target/src/spec/base/android.rs b/compiler/rustc_target/src/spec/base/android.rs index af15c16a5a9a8..d76956bdae9e9 100644 --- a/compiler/rustc_target/src/spec/base/android.rs +++ b/compiler/rustc_target/src/spec/base/android.rs @@ -1,11 +1,12 @@ -use crate::spec::{base, SanitizerSet, TargetOptions}; +use crate::spec::{base, SanitizerSet, TargetOptions, TlsModel}; pub fn opts() -> TargetOptions { let mut base = base::linux::opts(); base.os = "android".into(); base.is_like_android = true; base.default_dwarf_version = 2; - base.has_thread_local = false; + base.tls_model = TlsModel::EmulatedTls; + base.has_thread_local = true; base.supported_sanitizers = SanitizerSet::ADDRESS; // This is for backward compatibility, see https://github.com/rust-lang/rust/issues/49867 // for context. (At that time, there was no `-C force-unwind-tables`, so the only solution diff --git a/compiler/rustc_target/src/spec/base/linux_ohos.rs b/compiler/rustc_target/src/spec/base/linux_ohos.rs index 273e6a98dd4d2..15c1bb2d52768 100644 --- a/compiler/rustc_target/src/spec/base/linux_ohos.rs +++ b/compiler/rustc_target/src/spec/base/linux_ohos.rs @@ -1,11 +1,11 @@ -use crate::spec::{base, TargetOptions}; +use crate::spec::{base, TargetOptions, TlsModel}; pub fn opts() -> TargetOptions { let mut base = base::linux::opts(); base.env = "ohos".into(); base.crt_static_default = false; - base.force_emulated_tls = true; + base.tls_model = TlsModel::EmulatedTls; base.has_thread_local = false; base diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs index dbce2f30f9397..9e9d390053f1c 100644 --- a/compiler/rustc_target/src/spec/mod.rs +++ b/compiler/rustc_target/src/spec/mod.rs @@ -929,6 +929,7 @@ pub enum TlsModel { LocalDynamic, InitialExec, LocalExec, + EmulatedTls, } impl FromStr for TlsModel { @@ -942,6 +943,7 @@ impl FromStr for TlsModel { "local-dynamic" => TlsModel::LocalDynamic, "initial-exec" => TlsModel::InitialExec, "local-exec" => TlsModel::LocalExec, + "emulated-tls" => TlsModel::EmulatedTls, _ => return Err(()), }) } @@ -954,6 +956,7 @@ impl ToJson for TlsModel { TlsModel::LocalDynamic => "local-dynamic", TlsModel::InitialExec => "initial-exec", TlsModel::LocalExec => "local-exec", + TlsModel::EmulatedTls => "emulated-tls", } .to_json() } @@ -2190,9 +2193,6 @@ pub struct TargetOptions { /// Whether the target supports XRay instrumentation. pub supports_xray: bool, - - /// Forces the use of emulated TLS (__emutls_get_address) - pub force_emulated_tls: bool, } /// Add arguments for the given flavor and also for its "twin" flavors @@ -2408,7 +2408,6 @@ impl Default for TargetOptions { entry_name: "main".into(), entry_abi: Conv::C, supports_xray: false, - force_emulated_tls: false, } } } @@ -3112,7 +3111,6 @@ impl Target { key!(entry_name); key!(entry_abi, Conv)?; key!(supports_xray, bool); - key!(force_emulated_tls, bool); if base.is_builtin { // This can cause unfortunate ICEs later down the line. @@ -3368,7 +3366,6 @@ impl ToJson for Target { target_option_val!(entry_name); target_option_val!(entry_abi); target_option_val!(supports_xray); - target_option_val!(force_emulated_tls); if let Some(abi) = self.default_adjusted_cabi { d.insert("default-adjusted-cabi".into(), Abi::name(abi).to_json()); diff --git a/library/std/src/sys/unix/thread_local_dtor.rs b/library/std/src/sys/unix/thread_local_dtor.rs index 667fd51696249..ac85531c372ea 100644 --- a/library/std/src/sys/unix/thread_local_dtor.rs +++ b/library/std/src/sys/unix/thread_local_dtor.rs @@ -12,7 +12,13 @@ // compiling from a newer linux to an older linux, so we also have a // fallback implementation to use as well. #[allow(unexpected_cfgs)] -#[cfg(any(target_os = "linux", target_os = "fuchsia", target_os = "redox", target_os = "hurd"))] +#[cfg(any( + target_os = "linux", + target_os = "android", + target_os = "fuchsia", + target_os = "redox", + target_os = "hurd" +))] // FIXME: The Rust compiler currently omits weakly function definitions (i.e., // __cxa_thread_atexit_impl) and its metadata from LLVM IR. #[no_sanitize(cfi, kcfi)] diff --git a/src/doc/unstable-book/src/compiler-flags/tls-model.md b/src/doc/unstable-book/src/compiler-flags/tls-model.md index 8b19e785c6a5b..c724f38b4af9d 100644 --- a/src/doc/unstable-book/src/compiler-flags/tls-model.md +++ b/src/doc/unstable-book/src/compiler-flags/tls-model.md @@ -20,6 +20,8 @@ loaded at program startup. The TLS data must not be in a library loaded after startup (via `dlopen`). - `local-exec` - model usable only if the TLS data is defined directly in the executable, but not in a shared library, and is accessed only from that executable. +- `emulated-tls` - Uses thread-specific data keys to implement emulated TLS. +It is like using a general-dynamic TLS model for all modes. `rustc` and LLVM may use a more optimized model than specified if they know that we are producing an executable rather than a library, or that the `static` item is private enough.