[TableGen] Improve generated comments for RegClassByHwMode tables

Adding a comment for which RegClassByHwMode the entry refers to is
helpful when staring at this generated table.

Pull Request: #171716

Author: arichardson

llvm/test/TableGen/RegClassByHwMode.td

@@ -42,24 +42,24 @@ include "Common/RegClassByHwModeCommon.td"
 
 // INSTRINFO: extern const int16_t MyTargetRegClassByHwModeTables[4][3] = {
 // INSTRINFO-NEXT:  { // DefaultMode
-// INSTRINFO-NEXT:    MyTarget::PtrRegs32RegClassID,
-// INSTRINFO-NEXT:    MyTarget::XRegsRegClassID,
-// INSTRINFO-NEXT:    MyTarget::YRegsRegClassID,
+// INSTRINFO-NEXT:    MyTarget::PtrRegs32RegClassID, // MyPtrRC
+// INSTRINFO-NEXT:    MyTarget::XRegsRegClassID, // XRegs_EvenIfRequired
+// INSTRINFO-NEXT:    MyTarget::YRegsRegClassID, // YRegs_EvenIfRequired
 // INSTRINFO-NEXT:  },
 // INSTRINFO-NEXT:  { // EvenMode
-// INSTRINFO-NEXT:    -1, // Missing mode entry
-// INSTRINFO-NEXT:    MyTarget::XRegs_EvenRegClassID,
-// INSTRINFO-NEXT:    MyTarget::YRegs_EvenRegClassID,
+// INSTRINFO-NEXT:    -1, // Missing mode entry for MyPtrRC
+// INSTRINFO-NEXT:    MyTarget::XRegs_EvenRegClassID, // XRegs_EvenIfRequired
+// INSTRINFO-NEXT:    MyTarget::YRegs_EvenRegClassID, // YRegs_EvenIfRequired
 // INSTRINFO-NEXT:  },
 // INSTRINFO-NEXT:  { // OddMode
-// INSTRINFO-NEXT:    -1, // Missing mode entry
-// INSTRINFO-NEXT:    MyTarget::XRegs_OddRegClassID,
-// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:    -1, // Missing mode entry for MyPtrRC
+// INSTRINFO-NEXT:    MyTarget::XRegs_OddRegClassID, // XRegs_EvenIfRequired
+// INSTRINFO-NEXT:    -1, // Missing mode entry for YRegs_EvenIfRequired
 // INSTRINFO-NEXT:  },
 // INSTRINFO-NEXT:  { // Ptr64
-// INSTRINFO-NEXT:    MyTarget::PtrRegs64RegClassID,
-// INSTRINFO-NEXT:    -1, // Missing mode entry
-// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:    MyTarget::PtrRegs64RegClassID, // MyPtrRC
+// INSTRINFO-NEXT:    -1, // Missing mode entry for XRegs_EvenIfRequired
+// INSTRINFO-NEXT:    -1, // Missing mode entry for YRegs_EvenIfRequired
 // INSTRINFO-NEXT:  },
 // INSTRINFO-NEXT: };
 
@@ -92,24 +92,24 @@ include "Common/RegClassByHwModeCommon.td"
 // ASMMATCHER: if (Operand.isReg() && Kind > MCK_LAST_REGISTER && Kind <= MCK_LAST_REGCLASS_BY_HWMODE) {
 // ASMMATCHER-NEXT:    static constexpr MatchClassKind RegClassByHwModeMatchTable[4][3] = {
 // ASMMATCHER-NEXT:      { // DefaultMode
-// ASMMATCHER-NEXT:        MCK_PtrRegs32,
-// ASMMATCHER-NEXT:        MCK_XRegs,
-// ASMMATCHER-NEXT:        MCK_YRegs,
+// ASMMATCHER-NEXT:        MCK_PtrRegs32, // MyPtrRC
+// ASMMATCHER-NEXT:        MCK_XRegs, // XRegs_EvenIfRequired
+// ASMMATCHER-NEXT:        MCK_YRegs, // YRegs_EvenIfRequired
 // ASMMATCHER-NEXT:      },
 // ASMMATCHER-NEXT:      { // EvenMode
-// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode
-// ASMMATCHER-NEXT:        MCK_XRegs_Even,
-// ASMMATCHER-NEXT:        MCK_YRegs_Even,
+// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode entry for MyPtrRC
+// ASMMATCHER-NEXT:        MCK_XRegs_Even, // XRegs_EvenIfRequired
+// ASMMATCHER-NEXT:        MCK_YRegs_Even, // YRegs_EvenIfRequired
 // ASMMATCHER-NEXT:      },
 // ASMMATCHER-NEXT:      { // OddMode
-// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode
-// ASMMATCHER-NEXT:        MCK_XRegs_Odd,
-// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode
+// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode entry for MyPtrRC
+// ASMMATCHER-NEXT:        MCK_XRegs_Odd, // XRegs_EvenIfRequired
+// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode entry for YRegs_EvenIfRequired
 // ASMMATCHER-NEXT:      },
 // ASMMATCHER-NEXT:      { // Ptr64
-// ASMMATCHER-NEXT:        MCK_PtrRegs64,
-// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode
-// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode
+// ASMMATCHER-NEXT:        MCK_PtrRegs64, // MyPtrRC
+// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode entry for XRegs_EvenIfRequired
+// ASMMATCHER-NEXT:        InvalidMatchClass, // Missing mode entry for YRegs_EvenIfRequired
 // ASMMATCHER-NEXT:      },
 // ASMMATCHER-NEXT:    };
 // ASMMATCHER-EMPTY:

llvm/utils/TableGen/AsmMatcherEmitter.cpp

@@ -2581,13 +2581,14 @@ static void emitValidateOperandClass(const CodeGenTarget &Target,
             });
 
         if (FoundMode == ModeSelect.Items.end()) {
-          OS << indent(8) << "InvalidMatchClass, // Missing mode\n";
+          OS << indent(8) << "InvalidMatchClass, // Missing mode entry for "
+             << Class->getName() << "\n";
         } else {
           const CodeGenRegisterClass *RegClass =
               RegBank.getRegClass(FoundMode->second);
           const ClassInfo *CI =
               Info.RegisterClassClasses.at(RegClass->getDef());
-          OS << indent(8) << CI->Name << ",\n";
+          OS << indent(8) << CI->Name << ", // " << Class->getName() << "\n";
         }
       }
 

llvm/utils/TableGen/InstrInfoEmitter.cpp

@@ -1116,11 +1116,13 @@ void InstrInfoEmitter::run(raw_ostream &OS) {
           if (FoundMode == ModeSelect.Items.end()) {
             // If a RegClassByHwMode doesn't have an entry corresponding to a
             // mode, pad with default register class.
-            OS << indent(4) << "-1, // Missing mode entry\n";
+            OS << indent(4) << "-1, // Missing mode entry for "
+               << Class->getName() << "\n";
           } else {
             const CodeGenRegisterClass *RegClass =
                 RegBank.getRegClass(FoundMode->second);
-            OS << indent(4) << RegClass->getQualifiedIdName() << ",\n";
+            OS << indent(4) << RegClass->getQualifiedIdName() << ", // "
+               << Class->getName() << "\n";
           }
         }