[AsmParser] Add DiagnosticString to register classes in tablegen

This allows a DiagnosticType and/or DiagnosticString to be associated
with a RegisterClass in tablegen, so that we can emit diagnostics in the
assembler when a register operand is incorrect.

DiagnosticType creates a predictable enum value, which gets returned as
the error code when an operand does not match, and can be used by the
assembly parser to map to a user-facing diagnostic. DiagnosticString
creates an anonymous enum value (currently based on the tablegen class
name), and a function to map from enum values to strings will be
generated. Both of these work the same was as they do for AsmOperand.

This isn't used by any targets yet, but has one (positive) side-effect.
It improves the diagnostic codes returned by validateOperandClass - we
always want to emit the diagnostic that relates to the expected operand
class, but this wasn't always being done when the expected and actual
classes were completely different (token/register/custom). This causes a
few AArch64 diagnostics to be improved, as Match_InvalidOperand was
being returned instead of a specific diagnostic type.

Differential revision: https://reviews.llvm.org/D36691

llvm-svn: 315295

1 files changed, 68 insertions, 9 deletions

diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
index 191dbdea098..60ec8c3eef2 100644
--- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
@@ -704,13 +704,13 @@ public:
   /// Map of AsmOperandClass records to their class information.
   std::map<Record*, ClassInfo*> AsmOperandClasses;
 
+  /// Map of RegisterClass records to their class information.
+  std::map<Record*, ClassInfo*> RegisterClassClasses;
+
 private:
   /// Map of token to class information which has already been constructed.
   std::map<std::string, ClassInfo*> TokenClasses;
 
-  /// Map of RegisterClass records to their class information.
-  std::map<Record*, ClassInfo*> RegisterClassClasses;
-
 private:
   /// getTokenClass - Lookup or create the class for the given token.
   ClassInfo *getTokenClass(StringRef Token);
@@ -1282,6 +1282,19 @@ buildRegisterClasses(SmallPtrSetImpl<Record*> &SingletonRegisters) {
     } else
       CI->ValueName = CI->ValueName + "," + RC.getName();
 
+    Init *DiagnosticType = Def->getValueInit("DiagnosticType");
+    if (StringInit *SI = dyn_cast<StringInit>(DiagnosticType))
+      CI->DiagnosticType = SI->getValue();
+
+    Init *DiagnosticString = Def->getValueInit("DiagnosticString");
+    if (StringInit *SI = dyn_cast<StringInit>(DiagnosticString))
+      CI->DiagnosticString = SI->getValue();
+
+    // If we have a diagnostic string but the diagnostic type is not specified
+    // explicitly, create an anonymous diagnostic type.
+    if (!CI->DiagnosticString.empty() && CI->DiagnosticType.empty())
+      CI->DiagnosticType = RC.getName();
+
     RegisterClassClasses.insert(std::make_pair(Def, CI));
   }
 
@@ -2178,7 +2191,18 @@ static void emitMatchClassEnumeration(CodeGenTarget &Target,
   OS << "enum MatchClassKind {\n";
   OS << "  InvalidMatchClass = 0,\n";
   OS << "  OptionalMatchClass = 1,\n";
+  ClassInfo::ClassInfoKind LastKind = ClassInfo::Token;
+  StringRef LastName = "OptionalMatchClass";
   for (const auto &CI : Infos) {
+    if (LastKind == ClassInfo::Token && CI.Kind != ClassInfo::Token) {
+      OS << "  MCK_LAST_TOKEN = " << LastName << ",\n";
+    } else if (LastKind < ClassInfo::UserClass0 &&
+               CI.Kind >= ClassInfo::UserClass0) {
+      OS << "  MCK_LAST_REGISTER = " << LastName << ",\n";
+    }
+    LastKind = (ClassInfo::ClassInfoKind)CI.Kind;
+    LastName = CI.Name;
+
     OS << "  " << CI.Name << ", // ";
     if (CI.Kind == ClassInfo::Token) {
       OS << "'" << CI.ValueName << "'\n";
@@ -2229,6 +2253,26 @@ static void emitOperandMatchErrorDiagStrings(AsmMatcherInfo &Info, raw_ostream &
   OS << "}\n\n";
 }
 
+static void emitRegisterMatchErrorFunc(AsmMatcherInfo &Info, raw_ostream &OS) {
+  OS << "static unsigned getDiagKindFromRegisterClass(MatchClassKind "
+        "RegisterClass) {\n";
+  OS << "  switch (RegisterClass) {\n";
+
+  for (const auto &CI: Info.Classes) {
+    if (CI.isRegisterClass() && !CI.DiagnosticType.empty()) {
+      OS << "  case " << CI.Name << ":\n";
+      OS << "    return " << Info.Target.getName() << "AsmParser::Match_"
+         << CI.DiagnosticType << ";\n";
+    }
+  }
+
+  OS << "  default:\n";
+  OS << "    return MCTargetAsmParser::Match_InvalidOperand;\n";
+
+  OS << "  }\n";
+  OS << "}\n\n";
+}
+
 /// emitValidateOperandClass - Emit the function to validate an operand class.
 static void emitValidateOperandClass(AsmMatcherInfo &Info,
                                      raw_ostream &OS) {
@@ -2243,7 +2287,7 @@ static void emitValidateOperandClass(AsmMatcherInfo &Info,
 
   // Check for Token operands first.
   // FIXME: Use a more specific diagnostic type.
-  OS << "  if (Operand.isToken())\n";
+  OS << "  if (Operand.isToken() && Kind <= MCK_LAST_TOKEN)\n";
   OS << "    return isSubclass(matchTokenString(Operand.getToken()), Kind) ?\n"
      << "             MCTargetAsmParser::Match_Success :\n"
      << "             MCTargetAsmParser::Match_InvalidOperand;\n\n";
@@ -2279,8 +2323,12 @@ static void emitValidateOperandClass(AsmMatcherInfo &Info,
        << "; break;\n";
   OS << "    }\n";
   OS << "    return isSubclass(OpKind, Kind) ? "
-     << "MCTargetAsmParser::Match_Success :\n                             "
-     << "         MCTargetAsmParser::Match_InvalidOperand;\n  }\n\n";
+     << "(unsigned)MCTargetAsmParser::Match_Success :\n                     "
+     << "                 getDiagKindFromRegisterClass(Kind);\n  }\n\n";
+
+  // Expected operand is a register, but actual is not.
+  OS << "  if (Kind > MCK_LAST_TOKEN && Kind <= MCK_LAST_REGISTER)\n";
+  OS << "    return getDiagKindFromRegisterClass(Kind);\n\n";
 
   // Generic fallthrough match failure case for operands that don't have
   // specialized diagnostic types.
@@ -2429,6 +2477,10 @@ static void emitOperandDiagnosticTypes(AsmMatcherInfo &Info, raw_ostream &OS) {
     if (!OpClassEntry.second->DiagnosticType.empty())
       Types.insert(OpClassEntry.second->DiagnosticType);
   }
+  for (const auto &OpClassEntry : Info.RegisterClassClasses) {
+    if (!OpClassEntry.second->DiagnosticType.empty())
+      Types.insert(OpClassEntry.second->DiagnosticType);
+  }
 
   if (Types.empty()) return;
 
@@ -2959,6 +3011,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   // match failure in diagnostics.
   emitOperandMatchErrorDiagStrings(Info, OS);
 
+  // Emit a function to map register classes to operand match failure codes.
+  emitRegisterMatchErrorFunc(Info, OS);
+
   // Emit the routine to match token strings to their match class.
   emitMatchTokenString(Target, Info.Classes, OS);
 
@@ -3226,12 +3281,16 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "      }\n";
   OS << "      // If the generic handler indicates an invalid operand\n";
   OS << "      // failure, check for a special case.\n";
-  OS << "      if (Diag == Match_InvalidOperand) {\n";
-  OS << "        Diag = validateTargetOperandClass(Actual, Formal);\n";
-  OS << "        if (Diag == Match_Success) {\n";
+  OS << "      if (Diag != Match_Success) {\n";
+  OS << "        unsigned TargetDiag = validateTargetOperandClass(Actual, Formal);\n";
+  OS << "        if (TargetDiag == Match_Success) {\n";
   OS << "          ++ActualIdx;\n";
   OS << "          continue;\n";
   OS << "        }\n";
+  OS << "        // If the target matcher returned a specific error code use\n";
+  OS << "        // that, else use the one from the generic matcher.\n";
+  OS << "        if (TargetDiag != Match_InvalidOperand)\n";
+  OS << "          Diag = TargetDiag;\n";
   OS << "      }\n";
   OS << "      // If current formal operand wasn't matched and it is optional\n"
      << "      // then try to match next formal operand\n";