PR for llvm/llvm-project#79632 #79633
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@ilovepi What do you think about merging this PR to the release branch? |
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 llvm#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 <paulkirth@google.com> (cherry picked from commit 36b4a9c)
llvmbot
added
clang
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@llvm/pr-subscribers-clang-codegen @llvm/pr-subscribers-clang-driver Author: None (github-actions[bot]) Changesresolves llvm/llvm-project#79632 Full diff: https://github.com/llvm/llvm-project/pull/79633.diff 9 Files Affected:
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 fadaf3e60c6616a..ff4047298d70d52 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -729,6 +729,33 @@ 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) {
@@ -988,6 +1015,9 @@ 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.
|
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Merged: aa4cb0e |
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resolves #79632