Author: Fangrui Song Date: 2024-01-26T09:25:38-08:00 New Revision: 36b4a9ccd9f7e04010476e6b2a311f2052a4ac20
URL: https://github.com/llvm/llvm-project/commit/36b4a9ccd9f7e04010476e6b2a311f2052a4ac20 DIFF: https://github.com/llvm/llvm-project/commit/36b4a9ccd9f7e04010476e6b2a311f2052a4ac20.diff LOG: [Driver,CodeGen] Support -mtls-dialect= (#79256) GCC supports -mtls-dialect= for several architectures to select TLSDESC. This patch supports the following values * x86: "gnu". "gnu2" (TLSDESC) is not supported yet. * RISC-V: "trad" (general dynamic), "desc" (TLSDESC, see #66915) AArch64 toolchains seem to support TLSDESC from the beginning, and the general dynamic model has poor support. Nobody seems to use the option -mtls-dialect= at all, so we don't bother with it. There also seems very little interest in AArch32's TLSDESC support. TLSDESC does not change IR, but affects object file generation. Without a backend option the option is a no-op for in-process ThinLTO. There seems no motivation to have fine-grained control mixing trad/desc for TLS, so we just pass -mllvm, and don't bother with a modules flag metadata or function attribute. Co-authored-by: Paul Kirth <paulki...@google.com> Added: clang/test/CodeGen/RISCV/tls-dialect.c clang/test/Driver/tls-dialect.c Modified: clang/include/clang/Basic/CodeGenOptions.def clang/include/clang/Driver/Options.td clang/lib/CodeGen/BackendUtil.cpp clang/lib/Driver/ToolChains/Clang.cpp clang/lib/Driver/ToolChains/CommonArgs.cpp clang/lib/Driver/ToolChains/CommonArgs.h llvm/include/llvm/TargetParser/Triple.h Removed: ################################################################################ diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def index 2f2e45d5cf63dfa..7c0bfe328496147 100644 --- a/clang/include/clang/Basic/CodeGenOptions.def +++ b/clang/include/clang/Basic/CodeGenOptions.def @@ -369,6 +369,9 @@ ENUM_CODEGENOPT(VecLib, llvm::driver::VectorLibrary, 3, llvm::driver::VectorLibr /// The default TLS model to use. ENUM_CODEGENOPT(DefaultTLSModel, TLSModel, 2, GeneralDynamicTLSModel) +/// Whether to enable TLSDESC. AArch64 enables TLSDESC regardless of this value. +CODEGENOPT(EnableTLSDESC, 1, 0) + /// Bit size of immediate TLS offsets (0 == use the default). VALUE_CODEGENOPT(TLSSize, 8, 0) diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 7f4fa33748facaf..773bc1dcda01d5c 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -4419,6 +4419,8 @@ def mtls_size_EQ : Joined<["-"], "mtls-size=">, Group<m_Group>, HelpText<"Specify bit size of immediate TLS offsets (AArch64 ELF only): " "12 (for 4KB) | 24 (for 16MB, default) | 32 (for 4GB) | 48 (for 256TB, needs -mcmodel=large)">, MarshallingInfoInt<CodeGenOpts<"TLSSize">>; +def mtls_dialect_EQ : Joined<["-"], "mtls-dialect=">, Group<m_Group>, + Flags<[TargetSpecific]>, HelpText<"Which thread-local storage dialect to use for dynamic accesses of TLS variables">; def mimplicit_it_EQ : Joined<["-"], "mimplicit-it=">, Group<m_Group>; def mdefault_build_attributes : Joined<["-"], "mdefault-build-attributes">, Group<m_Group>; def mno_default_build_attributes : Joined<["-"], "mno-default-build-attributes">, Group<m_Group>; @@ -7066,6 +7068,9 @@ def fexperimental_assignment_tracking_EQ : Joined<["-"], "fexperimental-assignme Values<"disabled,enabled,forced">, NormalizedValues<["Disabled","Enabled","Forced"]>, MarshallingInfoEnum<CodeGenOpts<"AssignmentTrackingMode">, "Enabled">; +def enable_tlsdesc : Flag<["-"], "enable-tlsdesc">, + MarshallingInfoFlag<CodeGenOpts<"EnableTLSDESC">>; + } // let Visibility = [CC1Option] //===----------------------------------------------------------------------===// diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp index ec203f6f28bc173..7877e20d77f7724 100644 --- a/clang/lib/CodeGen/BackendUtil.cpp +++ b/clang/lib/CodeGen/BackendUtil.cpp @@ -401,6 +401,7 @@ static bool initTargetOptions(DiagnosticsEngine &Diags, Options.UniqueBasicBlockSectionNames = CodeGenOpts.UniqueBasicBlockSectionNames; Options.TLSSize = CodeGenOpts.TLSSize; + Options.EnableTLSDESC = CodeGenOpts.EnableTLSDESC; Options.EmulatedTLS = CodeGenOpts.EmulatedTLS; Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning(); Options.EmitStackSizeSection = CodeGenOpts.StackSizeSection; diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 5dc614e11aab599..8092fc050b0ee6d 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -5822,6 +5822,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, Args.AddLastArg(CmdArgs, options::OPT_mtls_size_EQ); } + if (isTLSDESCEnabled(TC, Args)) + CmdArgs.push_back("-enable-tlsdesc"); + // Add the target cpu std::string CPU = getCPUName(D, Args, Triple, /*FromAs*/ false); if (!CPU.empty()) { diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp index f20dd9f3b28dd6f..acc247447b98523 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -727,6 +727,33 @@ bool tools::isUseSeparateSections(const llvm::Triple &Triple) { return Triple.isPS(); } +bool tools::isTLSDESCEnabled(const ToolChain &TC, + const llvm::opt::ArgList &Args) { + const llvm::Triple &Triple = TC.getEffectiveTriple(); + Arg *A = Args.getLastArg(options::OPT_mtls_dialect_EQ); + if (!A) + return Triple.hasDefaultTLSDESC(); + StringRef V = A->getValue(); + bool SupportedArgument = false, EnableTLSDESC = false; + bool Unsupported = !Triple.isOSBinFormatELF(); + if (Triple.isRISCV()) { + SupportedArgument = V == "desc" || V == "trad"; + EnableTLSDESC = V == "desc"; + } else if (Triple.isX86()) { + SupportedArgument = V == "gnu"; + } else { + Unsupported = true; + } + if (Unsupported) { + TC.getDriver().Diag(diag::err_drv_unsupported_opt_for_target) + << A->getSpelling() << Triple.getTriple(); + } else if (!SupportedArgument) { + TC.getDriver().Diag(diag::err_drv_unsupported_option_argument_for_target) + << A->getSpelling() << V << Triple.getTriple(); + } + return EnableTLSDESC; +} + void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args, ArgStringList &CmdArgs, const InputInfo &Output, const InputInfo &Input, bool IsThinLTO) { @@ -1008,6 +1035,9 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args, CmdArgs.push_back( Args.MakeArgString(Twine(PluginOptPrefix) + "-emulated-tls")); } + if (isTLSDESCEnabled(ToolChain, Args)) + CmdArgs.push_back( + Args.MakeArgString(Twine(PluginOptPrefix) + "-enable-tlsdesc")); if (Args.hasFlag(options::OPT_fstack_size_section, options::OPT_fno_stack_size_section, false)) diff --git a/clang/lib/Driver/ToolChains/CommonArgs.h b/clang/lib/Driver/ToolChains/CommonArgs.h index 25d68345a9f9ebf..807867f13a5c301 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.h +++ b/clang/lib/Driver/ToolChains/CommonArgs.h @@ -144,6 +144,9 @@ llvm::StringRef getLTOParallelism(const llvm::opt::ArgList &Args, bool areOptimizationsEnabled(const llvm::opt::ArgList &Args); bool isUseSeparateSections(const llvm::Triple &Triple); +// Parse -mtls-dialect=. Return true if the target supports both general-dynamic +// and TLSDESC, and TLSDESC is requested. +bool isTLSDESCEnabled(const ToolChain &TC, const llvm::opt::ArgList &Args); /// \p EnvVar is split by system delimiter for environment variables. /// If \p ArgName is "-I", "-L", or an empty string, each entry from \p EnvVar diff --git a/clang/test/CodeGen/RISCV/tls-dialect.c b/clang/test/CodeGen/RISCV/tls-dialect.c new file mode 100644 index 000000000000000..e624a8b3fe4e676 --- /dev/null +++ b/clang/test/CodeGen/RISCV/tls-dialect.c @@ -0,0 +1,14 @@ +// REQUIRES: riscv-registered-target +/// cc1 -enable-tlsdesc (due to -mtls-dialect=desc) enables TLSDESC. +// RUN: %clang_cc1 -triple riscv64 -S -mrelocation-model pic -pic-level 1 -enable-tlsdesc %s -o - | FileCheck %s --check-prefix=DESC +// RUN: %clang_cc1 -triple riscv64 -S -mrelocation-model pic -pic-level 1 %s -o - | FileCheck %s --check-prefix=NODESC + +__thread int x; + +// DESC: %tlsdesc_hi +// DESC-NOT: %tls_gd_pcrel_hi +// NODESC: %tls_gd_pcrel_hi +// NODESC-NOT: %tlsdesc_hi +int use() { + return x; +} diff --git a/clang/test/Driver/tls-dialect.c b/clang/test/Driver/tls-dialect.c new file mode 100644 index 000000000000000..4e105ce3cea5d94 --- /dev/null +++ b/clang/test/Driver/tls-dialect.c @@ -0,0 +1,25 @@ +// RUN: %clang -### --target=riscv64-freebsd -mtls-dialect=desc %s 2>&1 | FileCheck --check-prefix=DESC %s +// RUN: %clang -### --target=riscv64-linux -mtls-dialect=trad %s 2>&1 | FileCheck --check-prefix=NODESC %s +// RUN: %clang -### --target=riscv64-linux %s 2>&1 | FileCheck --check-prefix=NODESC %s +// RUN: %clang -### --target=x86_64-linux -mtls-dialect=gnu %s 2>&1 | FileCheck --check-prefix=NODESC %s + +/// LTO +// RUN: %clang -### --target=riscv64-linux -flto -mtls-dialect=desc %s 2>&1 | FileCheck --check-prefix=LTO-DESC %s +// RUN: %clang -### --target=riscv64-linux -flto %s 2>&1 | FileCheck --check-prefix=LTO-NODESC %s + +/// Unsupported target +/// GCC supports -mtls-dialect= for AArch64, but we just unsupport it for AArch64 as it is very rarely used. +// RUN: not %clang --target=aarch64-linux -mtls-dialect=desc %s 2>&1 | FileCheck --check-prefix=UNSUPPORTED-TARGET %s +// RUN: not %clang --target=x86_64-apple-macos -mtls-dialect=desc -flto %s 2>&1 | FileCheck -check-prefix=UNSUPPORTED-TARGET %s + +/// Unsupported argument +// RUN: not %clang -### --target=riscv64-linux -mtls-dialect=gnu2 %s 2>&1 | FileCheck --check-prefix=UNSUPPORTED-ARG %s +// RUN: not %clang -### --target=x86_64-linux -mtls-dialect=gnu2 %s 2>&1 | FileCheck --check-prefix=UNSUPPORTED-ARG %s + +// DESC: "-cc1" {{.*}}"-enable-tlsdesc" +// NODESC-NOT: "-enable-tlsdesc" +// LTO-DESC: "-plugin-opt=-enable-tlsdesc" +// LTO-NODESC-NOT: "-plugin-opt=-enable-tlsdesc" + +// UNSUPPORTED-TARGET: error: unsupported option '-mtls-dialect=' for target +// UNSUPPORTED-ARG: error: unsupported argument 'gnu2' to option '-mtls-dialect=' for target diff --git a/llvm/include/llvm/TargetParser/Triple.h b/llvm/include/llvm/TargetParser/Triple.h index 870dc75b1c1f80f..49ec8de9c528de9 100644 --- a/llvm/include/llvm/TargetParser/Triple.h +++ b/llvm/include/llvm/TargetParser/Triple.h @@ -1033,11 +1033,11 @@ class Triple { isWindowsCygwinEnvironment() || isOHOSFamily(); } - /// Tests whether the target uses TLS Descriptor by default. + /// True if the target supports both general-dynamic and TLSDESC, and TLSDESC + /// is enabled by default. bool hasDefaultTLSDESC() const { // TODO: Improve check for other platforms, like Android, and RISC-V - // Note: This is currently only used on RISC-V. - return isOSBinFormatELF() && isAArch64(); + return false; } /// Tests whether the target uses -data-sections as default. _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
