This option allows selecting the TLS size in the local exec TLS model,

which is the default TLS model for non-PIC objects. This allows large/
many thread local variables or a compact/fast code in an executable.

Specification is same as that of GCC. For example, the code model
option precedes the TLS size option.

TLS access models other than local-exec are not changed. It means
supoort of the large code model is only in the local exec TLS model.

Patch By KAWASHIMA Takahiro (kawashima-fj <t-kawashima@fujitsu.com>)
Reviewers: dmgreen, mstorsjo, t.p.northover, peter.smith, ostannard
Reviewd By: peter.smith
Committed by: peter.smith

Differential Revision: https://reviews.llvm.org/D71688

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4ef40e974cd..4d924e072f5 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4531,6 +4531,19 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(A->getValue());
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_mtls_size_EQ)) {
+    StringRef Value = A->getValue();
+    unsigned TLSSize = 0;
+    Value.getAsInteger(10, TLSSize);
+    if (!Triple.isAArch64() || !Triple.isOSBinFormatELF())
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << A->getOption().getName() << TripleStr;
+    if (TLSSize != 12 && TLSSize != 24 && TLSSize != 32 && TLSSize != 48)
+      D.Diag(diag::err_drv_invalid_int_value)
+          << A->getOption().getName() << Value;
+    Args.AddLastArg(CmdArgs, options::OPT_mtls_size_EQ);
+  }
+
   // Add the target cpu
   std::string CPU = getCPUName(Args, Triple, /*FromAs*/ false);
   if (!CPU.empty()) {