[MIPS] Fix switching between 32/64-bit variants of r6 target triples

If clang driver gets 64-bit r6 target triple like `mipsisa64r6` and
additional option forces switching to generation of 32-bit code, it
loses r6 abi and generates 32-bit r2-r5 abi code.

```
$ clang -target mipsisa64r6-linux-gnu -mabi=32
```

This patch fixes the problem.

- Add optional `SubArchType` argument to the `Triple::setArch()` method.
- Implement generation of mips r6 target triples in the
  `Triple::getArchName()` method.

Differential Revision: https://reviews.llvm.org/D110514.diff

llvm/include/llvm/ADT/Triple.h

@@ -384,6 +384,9 @@ public:
   /// triple.
   StringRef getArchName() const;
 
+  /// getArchName - Get the architecture name based on Kind and SubArch.
+  StringRef getArchName(ArchType Kind, SubArchType SubArch = NoSubArch) const;
+
   /// getVendorName - Get the vendor (second) component of the triple.
   StringRef getVendorName() const;
 
@@ -838,7 +841,7 @@ public:
 
   /// setArch - Set the architecture (first) component of the triple
   /// to a known type.
-  void setArch(ArchType Kind);
+  void setArch(ArchType Kind, SubArchType SubArch = NoSubArch);
 
   /// setVendor - Set the vendor (second) component of the triple to a
   /// known type.

llvm/lib/Support/Triple.cpp

@@ -1030,6 +1030,30 @@ StringRef Triple::getArchName() const {
   return StringRef(Data).split('-').first;           // Isolate first component
 }
 
+StringRef Triple::getArchName(ArchType Kind, SubArchType SubArch) const {
+  switch (Kind) {
+  case Triple::mips:
+    if (SubArch == MipsSubArch_r6)
+      return "mipsisa32r6";
+    break;
+  case Triple::mipsel:
+    if (SubArch == MipsSubArch_r6)
+      return "mipsisa32r6el";
+    break;
+  case Triple::mips64:
+    if (SubArch == MipsSubArch_r6)
+      return "mipsisa64r6";
+    break;
+  case Triple::mips64el:
+    if (SubArch == MipsSubArch_r6)
+      return "mipsisa64r6el";
+    break;
+  default:
+    break;
+  }
+  return getArchTypeName(Kind);
+}
+
 StringRef Triple::getVendorName() const {
   StringRef Tmp = StringRef(Data).split('-').second; // Strip first component
   return Tmp.split('-').first;                       // Isolate second component
@@ -1211,8 +1235,8 @@ void Triple::setTriple(const Twine &Str) {
   *this = Triple(Str);
 }
 
-void Triple::setArch(ArchType Kind) {
+void Triple::setArch(ArchType Kind, SubArchType SubArch) {
-  setArchName(getArchTypeName(Kind));
+  setArchName(getArchName(Kind, SubArch));
 }
 
 void Triple::setVendor(VendorType Kind) {
@@ -1404,8 +1428,12 @@ Triple Triple::get32BitArchVariant() const {
   case Triple::amdil64:        T.setArch(Triple::amdil);   break;
   case Triple::hsail64:        T.setArch(Triple::hsail);   break;
   case Triple::le64:           T.setArch(Triple::le32);    break;
-  case Triple::mips64:         T.setArch(Triple::mips);    break;
+  case Triple::mips64:
-  case Triple::mips64el:       T.setArch(Triple::mipsel);  break;
+    T.setArch(Triple::mips, getSubArch());
+    break;
+  case Triple::mips64el:
+    T.setArch(Triple::mipsel, getSubArch());
+    break;
   case Triple::nvptx64:        T.setArch(Triple::nvptx);   break;
   case Triple::ppc64:          T.setArch(Triple::ppc);     break;
   case Triple::ppc64le:        T.setArch(Triple::ppcle);   break;
@@ -1470,8 +1498,12 @@ Triple Triple::get64BitArchVariant() const {
   case Triple::armeb:           T.setArch(Triple::aarch64_be); break;
   case Triple::hsail:           T.setArch(Triple::hsail64);    break;
   case Triple::le32:            T.setArch(Triple::le64);       break;
-  case Triple::mips:            T.setArch(Triple::mips64);     break;
+  case Triple::mips:
-  case Triple::mipsel:          T.setArch(Triple::mips64el);   break;
+    T.setArch(Triple::mips64, getSubArch());
+    break;
+  case Triple::mipsel:
+    T.setArch(Triple::mips64el, getSubArch());
+    break;
   case Triple::nvptx:           T.setArch(Triple::nvptx64);    break;
   case Triple::ppc:             T.setArch(Triple::ppc64);      break;
   case Triple::ppcle:           T.setArch(Triple::ppc64le);    break;
@@ -1532,8 +1564,12 @@ Triple Triple::getBigEndianArchVariant() const {
 
   case Triple::aarch64: T.setArch(Triple::aarch64_be); break;
   case Triple::bpfel:   T.setArch(Triple::bpfeb);      break;
-  case Triple::mips64el:T.setArch(Triple::mips64);     break;
+  case Triple::mips64el:
-  case Triple::mipsel:  T.setArch(Triple::mips);       break;
+    T.setArch(Triple::mips64, getSubArch());
+    break;
+  case Triple::mipsel:
+    T.setArch(Triple::mips, getSubArch());
+    break;
   case Triple::ppcle:   T.setArch(Triple::ppc);        break;
   case Triple::ppc64le: T.setArch(Triple::ppc64);      break;
   case Triple::sparcel: T.setArch(Triple::sparc);      break;
@@ -1565,8 +1601,12 @@ Triple Triple::getLittleEndianArchVariant() const {
 
   case Triple::aarch64_be: T.setArch(Triple::aarch64);  break;
   case Triple::bpfeb:      T.setArch(Triple::bpfel);    break;
-  case Triple::mips64:     T.setArch(Triple::mips64el); break;
+  case Triple::mips64:
-  case Triple::mips:       T.setArch(Triple::mipsel);   break;
+    T.setArch(Triple::mips64el, getSubArch());
+    break;
+  case Triple::mips:
+    T.setArch(Triple::mipsel, getSubArch());
+    break;
   case Triple::ppc:        T.setArch(Triple::ppcle);    break;
   case Triple::ppc64:      T.setArch(Triple::ppc64le);  break;
   case Triple::sparc:      T.setArch(Triple::sparcel);  break;

llvm/unittests/ADT/TripleTest.cpp

@@ -930,11 +930,27 @@ TEST(TripleTest, BitWidthArchVariants) {
 
   T.setArch(Triple::mips);
   EXPECT_EQ(Triple::mips, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get32BitArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get64BitArchVariant().getSubArch());
+
+  T.setArch(Triple::mips, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get32BitArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get64BitArchVariant().getSubArch());
 
   T.setArch(Triple::mipsel);
   EXPECT_EQ(Triple::mipsel, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get32BitArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64el, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get64BitArchVariant().getSubArch());
+
+  T.setArch(Triple::mipsel, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mipsel, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get32BitArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64el, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get64BitArchVariant().getSubArch());
 
   T.setArch(Triple::ppc);
   EXPECT_EQ(Triple::ppc, T.get32BitArchVariant().getArch());
@@ -954,11 +970,27 @@ TEST(TripleTest, BitWidthArchVariants) {
 
   T.setArch(Triple::mips64);
   EXPECT_EQ(Triple::mips, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get32BitArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get64BitArchVariant().getSubArch());
+
+  T.setArch(Triple::mips64, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get32BitArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get64BitArchVariant().getSubArch());
 
   T.setArch(Triple::mips64el);
   EXPECT_EQ(Triple::mipsel, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get32BitArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64el, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.get64BitArchVariant().getSubArch());
+
+  T.setArch(Triple::mips64el, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mipsel, T.get32BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get32BitArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64el, T.get64BitArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.get64BitArchVariant().getSubArch());
 
   T.setArch(Triple::ppc64);
   EXPECT_EQ(Triple::ppc, T.get32BitArchVariant().getArch());
@@ -1104,19 +1136,55 @@ TEST(TripleTest, EndianArchVariants) {
 
   T.setArch(Triple::mips64);
   EXPECT_EQ(Triple::mips64, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getBigEndianArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64el, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getLittleEndianArchVariant().getSubArch());
+
+  T.setArch(Triple::mips64, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips64, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.getBigEndianArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64el, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6,
+            T.getLittleEndianArchVariant().getSubArch());
 
   T.setArch(Triple::mips64el);
   EXPECT_EQ(Triple::mips64, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getBigEndianArchVariant().getSubArch());
   EXPECT_EQ(Triple::mips64el, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getLittleEndianArchVariant().getSubArch());
+
+  T.setArch(Triple::mips64el, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips64, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.getBigEndianArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mips64el, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6,
+            T.getLittleEndianArchVariant().getSubArch());
 
   T.setArch(Triple::mips);
   EXPECT_EQ(Triple::mips, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getBigEndianArchVariant().getSubArch());
   EXPECT_EQ(Triple::mipsel, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getLittleEndianArchVariant().getSubArch());
+
+  T.setArch(Triple::mips, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.getBigEndianArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mipsel, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6,
+            T.getLittleEndianArchVariant().getSubArch());
 
   T.setArch(Triple::mipsel);
   EXPECT_EQ(Triple::mips, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getBigEndianArchVariant().getSubArch());
   EXPECT_EQ(Triple::mipsel, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getLittleEndianArchVariant().getSubArch());
+
+  T.setArch(Triple::mipsel, Triple::MipsSubArch_r6);
+  EXPECT_EQ(Triple::mips, T.getBigEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6, T.getBigEndianArchVariant().getSubArch());
+  EXPECT_EQ(Triple::mipsel, T.getLittleEndianArchVariant().getArch());
+  EXPECT_EQ(Triple::MipsSubArch_r6,
+            T.getLittleEndianArchVariant().getSubArch());
 
   T.setArch(Triple::ppc);
   EXPECT_EQ(Triple::ppc, T.getBigEndianArchVariant().getArch());