[X86][PowerPC] Support -mlong-double-128

This patch makes the driver option -mlong-double-128 available for X86
and PowerPC. The CC1 option -mlong-double-128 is available on all targets
for users to test on unsupported targets.

On PowerPC, -mlong-double-128 uses the IBM extended double format
because we don't support -mabi=ieeelongdouble yet (D64283).

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D64277

llvm-svn: 365866
diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 43ab772..a9dfe69 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -373,10 +373,15 @@
     LongDoubleFormat = &llvm::APFloat::IEEEquad();
   }
 
-  if (Opts.LongDoubleSize && Opts.LongDoubleSize == DoubleWidth) {
-    LongDoubleWidth = DoubleWidth;
-    LongDoubleAlign = DoubleAlign;
-    LongDoubleFormat = DoubleFormat;
+  if (Opts.LongDoubleSize) {
+    if (Opts.LongDoubleSize == DoubleWidth) {
+      LongDoubleWidth = DoubleWidth;
+      LongDoubleAlign = DoubleAlign;
+      LongDoubleFormat = DoubleFormat;
+    } else if (Opts.LongDoubleSize == 128) {
+      LongDoubleWidth = LongDoubleAlign = 128;
+      LongDoubleFormat = &llvm::APFloat::IEEEquad();
+    }
   }
 
   if (Opts.NewAlignOverride)
diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
index b052ef4..bd0ae60 100644
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -465,6 +465,8 @@
   if (HasAltivec)
     Opts.AltiVec = 1;
   TargetInfo::adjust(Opts);
+  if (LongDoubleFormat != &llvm::APFloat::IEEEdouble())
+    LongDoubleFormat = &llvm::APFloat::PPCDoubleDouble();
 }
 
 ArrayRef<Builtin::Info> PPCTargetInfo::getTargetBuiltins() const {
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index c0dfc81..588b6d3 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -133,6 +133,10 @@
     LongDoubleFormat = &llvm::APFloat::x87DoubleExtended();
   }
 
+  const char *getLongDoubleMangling() const override {
+    return LongDoubleFormat == &llvm::APFloat::IEEEquad() ? "g" : "e";
+  }
+
   unsigned getFloatEvalMethod() const override {
     // X87 evaluates with 80 bits "long double" precision.
     return SSELevel == NoSSE ? 2 : 0;
@@ -845,8 +849,6 @@
       : LinuxTargetInfo<X86_64TargetInfo>(Triple, Opts) {
     LongDoubleFormat = &llvm::APFloat::IEEEquad();
   }
-
-  const char *getLongDoubleMangling() const override { return "g"; }
 };
 } // namespace targets
 } // namespace clang
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 1636018..719123f 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4012,15 +4012,15 @@
 
   RenderFloatingPointOptions(TC, D, OFastEnabled, Args, CmdArgs);
 
-  if (Arg *A = Args.getLastArg(options::OPT_mlong_double_64)) {
+  if (Arg *A = Args.getLastArg(options::OPT_mlong_double_64,
+                               options::OPT_mlong_double_128)) {
     if (TC.getArch() == llvm::Triple::x86 ||
         TC.getArch() == llvm::Triple::x86_64 ||
-        TC.getArch() == llvm::Triple::ppc || TC.getTriple().isPPC64()) {
-      CmdArgs.push_back("-mlong-double-64");
-    } else {
+        TC.getArch() == llvm::Triple::ppc || TC.getTriple().isPPC64())
+      A->render(Args, CmdArgs);
+    else
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
-    }
   }
 
   // Decide whether to use verbose asm. Verbose assembly is the default on
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0d9e29d..7a07d99 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2742,7 +2742,9 @@
   Opts.PackStruct = getLastArgIntValue(Args, OPT_fpack_struct_EQ, 0, Diags);
   Opts.MaxTypeAlign = getLastArgIntValue(Args, OPT_fmax_type_align_EQ, 0, Diags);
   Opts.AlignDouble = Args.hasArg(OPT_malign_double);
-  Opts.LongDoubleSize = Args.hasArg(OPT_mlong_double_64) ? 64 : 0;
+  Opts.LongDoubleSize = Args.hasArg(OPT_mlong_double_128)
+                            ? 128
+                            : Args.hasArg(OPT_mlong_double_64) ? 64 : 0;
   Opts.PICLevel = getLastArgIntValue(Args, OPT_pic_level, 0, Diags);
   Opts.ROPI = Args.hasArg(OPT_fropi);
   Opts.RWPI = Args.hasArg(OPT_frwpi);