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

[atanasyan]

Summary

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.

1. 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.
2. The getUnwindWordWidth virtual function override in the MipsTargetInfo class and provides correct type size values.

lib/Basic/Targets/Mips.h

if (ABI == "o32")
       return llvm::makeArrayRef(O32RegAliases);
     return llvm::makeArrayRef(NewABIRegAliases);
   }
 
   bool hasInt128Type() const override {
     return (ABI == "n32" || ABI == "n64") || getTargetOpts().ForceEnableInt128;
   }
 
+  unsigned getUnwindWordWidth() const override;
+
   bool validateTarget(DiagnosticsEngine &Diags) const override;
 };
 } // namespace targets
 } // namespace clang
 
 #endif // LLVM_CLANG_LIB_BASIC_TARGETS_MIPS_H

lib/Basic/Targets/Mips.cpp

return llvm::StringSwitch<bool>(Feature)
       .Default(false);
 }
 
 ArrayRef<Builtin::Info> MipsTargetInfo::getTargetBuiltins() const {
   return llvm::makeArrayRef(BuiltinInfo, clang::Mips::LastTSBuiltin -
                                              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")) {
     Diags.Report(diag::err_target_unsupported_cpu_for_micromips) << CPU;
     return false;
   }
   // FIXME: It's valid to use O32 on a 64-bit CPU but the backend can't handle
   //        this yet. It's better to fail here than on the backend assertion.

lib/Headers/unwind.h

 
 /* It is a bit strange for a header to play with the visibility of the
    symbols it declares, but this matches gcc's behavior and some programs
    depend on it */
 #ifndef HIDE_EXPORTS
 #pragma GCC visibility push(default)
 #endif
 
-typedef uintptr_t _Unwind_Word;
-typedef intptr_t _Unwind_Sword;
+typedef uintptr_t _Unwind_Word __attribute__((__mode__(__unwind_word__)));
+typedef intptr_t _Unwind_Sword __attribute__((__mode__(__unwind_word__)));
 typedef uintptr_t _Unwind_Ptr;
 typedef uintptr_t _Unwind_Internal_Ptr;
 typedef uint64_t _Unwind_Exception_Class;
 
 typedef intptr_t _sleb128_t;
 typedef uintptr_t _uleb128_t;
 
 struct _Unwind_Context;

test/Sema/attr-mode.c

 // RUN: %clang_cc1 -triple i686-pc-linux-gnu -DTEST_32BIT_X86 -fsyntax-only \
 // RUN:   -verify %s
 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -DTEST_64BIT_X86 -fsyntax-only \
 // RUN:   -verify %s
 // RUN: %clang_cc1 -triple powerpc64-pc-linux-gnu -DTEST_64BIT_PPC64 -fsyntax-only \
 // RUN:   -verify %s
 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnux32 -DTEST_64BIT_X86 -fsyntax-only \
 // RUN:   -verify %s
+// RUN: %clang_cc1 -triple mips-linux-gnu -DTEST_MIPS_32 -fsyntax-only \
+// RUN:   -verify %s
+// RUN: %clang_cc1 -triple mips64-linux-gnuabin32 -DTEST_MIPS_N32 -fsyntax-only \
+// RUN:   -verify %s
+// RUN: %clang_cc1 -triple mips64-linux-gnu -DTEST_MIPS_64 -fsyntax-only \
+// RUN:   -verify %s
 
 typedef int i16_1 __attribute((mode(HI)));
 int i16_1_test[sizeof(i16_1) == 2 ? 1 : -1];
 typedef int i16_2 __attribute((__mode__(__HI__)));
 int i16_2_test[sizeof(i16_1) == 2 ? 1 : -1];
 
 typedef float f64 __attribute((mode(DF)));
 int f64_test[sizeof(f64) == 8 ? 1 : -1];

 
 __attribute__((mode(QI))) int invalid_func() { return 1; } // expected-error{{'mode' attribute only applies to variables, enums, typedefs, and non-static data members}}
 enum invalid_enum { A1 __attribute__((mode(QI))) }; // expected-error{{'mode' attribute only applies to}}
 
 typedef _Complex double c32 __attribute((mode(SC)));
 int c32_test[sizeof(c32) == 8 ? 1 : -1];
 typedef _Complex float c64 __attribute((mode(DC)));
 
-#ifndef TEST_64BIT_PPC64 // Note, 'XC' mode is illegal for PPC64 machines.
+#if !defined(__ppc__) && !defined(__mips__) // Note, 'XC' mode is illegal for PPC64 and MIPS machines.
 typedef _Complex float c80 __attribute((mode(XC)));
 #endif
 
 // PR6108: Correctly select 'long' built in type on 64-bit platforms for 64 bit
 // modes. Also test other mode-based conversions.
 typedef int i8_mode_t __attribute__ ((__mode__ (__QI__)));
 typedef unsigned int ui8_mode_t __attribute__ ((__mode__ (__QI__)));
 typedef int i16_mode_t __attribute__ ((__mode__ (__HI__)));

 typedef          float f128ibm __attribute__ ((mode (TF)));
 #elif TEST_64BIT_PPC64
 typedef          float f128ibm __attribute__ ((mode (TF)));
 typedef _Complex float c128ibm __attribute__ ((mode (TC)));
 void f_ft128_arg(long double *x);
 void f_ft128_complex_arg(_Complex long double *x);
 void test_TFtype(f128ibm *a) { f_ft128_arg (a); }
 void test_TCtype(c128ibm *a) { f_ft128_complex_arg (a); }
+#elif TEST_MIPS_32
+typedef unsigned int gcc_unwind_word __attribute__((mode(unwind_word)));
+int foo[sizeof(gcc_unwind_word) == 4 ? 1 : -1];
+#elif TEST_MIPS_N32
+typedef unsigned int gcc_unwind_word __attribute__((mode(unwind_word)));
+int foo[sizeof(gcc_unwind_word) == 8 ? 1 : -1];
+#elif TEST_MIPS_64
+typedef unsigned int gcc_unwind_word __attribute__((mode(unwind_word)));
+int foo[sizeof(gcc_unwind_word) == 8 ? 1 : -1];
 #else
 #error Unknown test architecture.
 #endif
 
 struct S {
   int n __attribute((mode(HI)));
 };