[Headers][mips] Add `__attribute__((__mode__(__unwind_word__)))` to the _Unwind_Word / _Unwind_SWord definitions

The rationale of this change is to fix _Unwind_Word / _Unwind_SWord
definitions for MIPS N32 ABI. This ABI uses 32-bit pointers,
but _Unwind_Word and _Unwind_SWord types are eight bytes long.

 # The __attribute__((__mode__(__unwind_word__))) is added to the type
   definitions. It makes them equal to the corresponding definitions used
   by GCC and allows to override types using `getUnwindWordWidth` function.
 # The `getUnwindWordWidth` virtual function override in the `MipsTargetInfo`
   class and provides correct type size values.

Differential revision: https://reviews.llvm.org/D58165

llvm-svn: 353965

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets/Mips.cpp b/clang/lib/Basic/Targets/Mips.cpp
index 840ad1bc627..2cafbe87a99 100644
--- a/clang/lib/Basic/Targets/Mips.cpp
+++ b/clang/lib/Basic/Targets/Mips.cpp
@@ -215,6 +215,14 @@ ArrayRef<Builtin::Info> MipsTargetInfo::getTargetBuiltins() const {
                                              Builtin::FirstTSBuiltin);
 }
 
+unsigned MipsTargetInfo::getUnwindWordWidth() const {
+  return llvm::StringSwitch<unsigned>(ABI)
+      .Case("o32", 32)
+      .Case("n32", 64)
+      .Case("n64", 64)
+      .Default(getPointerWidth(0));
+}
+
 bool MipsTargetInfo::validateTarget(DiagnosticsEngine &Diags) const {
   // microMIPS64R6 backend was removed.
   if (getTriple().isMIPS64() && IsMicromips && (ABI == "n32" || ABI == "n64")) {