Swizzle the target triple based on -mthumb, and update clang-cc to recognize
thumb-foo-bar as an ARM target.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81497 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/Options.def b/include/clang/Driver/Options.def
index 4961cc9..c72bf36 100644
--- a/include/clang/Driver/Options.def
+++ b/include/clang/Driver/Options.def
@@ -536,6 +536,7 @@
 OPTION("-mno-sse4", mno_sse4, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
 OPTION("-mno-sse", mno_sse, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
 OPTION("-mno-ssse3", mno_ssse3, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
+OPTION("-mno-thumb", mno_thumb, Flag, m_Group, INVALID, "", 0, 0, 0)
 OPTION("-mno-warn-nonportable-cfstrings", mno_warn_nonportable_cfstrings, Flag, m_Group, INVALID, "", 0, 0, 0)
 OPTION("-mpascal-strings", mpascal_strings, Flag, m_Group, INVALID, "", 0, 0, 0)
 OPTION("-mred-zone", mred_zone, Flag, m_Group, INVALID, "", 0, 0, 0)
@@ -546,6 +547,7 @@
 OPTION("-msse4", msse4, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
 OPTION("-msse", msse, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
 OPTION("-mssse3", mssse3, Flag, m_x86_Features_Group, INVALID, "", 0, 0, 0)
+OPTION("-mthumb", mthumb, Flag, m_Group, INVALID, "", 0, 0, 0)
 OPTION("-mtune=", mtune_EQ, Joined, m_Group, INVALID, "", 0, 0, 0)
 OPTION("-multi_module", multi__module, Flag, INVALID, INVALID, "", 0, 0, 0)
 OPTION("-multiply_defined_unused", multiply__defined__unused, Separate, INVALID, INVALID, "", 0, 0, 0)
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 4e63db6..2cb6253 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1558,6 +1558,7 @@
     return NULL;
 
   case llvm::Triple::arm:
+  case llvm::Triple::thumb:
     switch (os) {
     case llvm::Triple::Darwin:
       return new DarwinARMTargetInfo(T);
diff --git a/lib/CodeGen/TargetABIInfo.cpp b/lib/CodeGen/TargetABIInfo.cpp
index daeec0a..67e2597 100644
--- a/lib/CodeGen/TargetABIInfo.cpp
+++ b/lib/CodeGen/TargetABIInfo.cpp
@@ -1551,6 +1551,7 @@
     return *(TheABIInfo = new X86_64ABIInfo());
 
   case llvm::Triple::arm:
+  case llvm::Triple::thumb:
     // FIXME: Support for OABI?
     return *(TheABIInfo = new ARMABIInfo());
 
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 05a73b9..9a037c6 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -297,11 +297,20 @@
 
   case llvm::Triple::arm:
   case llvm::Triple::thumb: {
+    // FIXME: Factor into subclasses.
     llvm::Triple Triple = TC.getTriple();
-    // FIXME: Thumb!
+
+    // Thumb2 is the default for V7 on Darwin.
+    //
+    // FIXME: Thumb should just be another -target-feaure, not in the triple.
+    llvm::StringRef Suffix = getLLVMArchSuffixForARM(getARMTargetCPU(Args));
+    bool ThumbDefault =
+      (Suffix == "v7" && TC.getTriple().getOS() == llvm::Triple::Darwin);
     std::string ArchName = "arm";
-    ArchName += getLLVMArchSuffixForARM (getARMTargetCPU(Args));
-    Triple.setArchName(ArchName);
+    if (Args.hasFlag(options::OPT_mthumb, options::OPT_mno_thumb, ThumbDefault))
+      ArchName = "thumb";
+    Triple.setArchName(ArchName + Suffix.str());
+
     return Triple.getTriple();
   }
   }