MCTargetAsmParser target match predicate support.

Allow a target assembly parser to do context sensitive constraint checking
on a potential instruction match. This will be used, for example, to handle
Thumb2 IT block parsing.

llvm-svn: 137675

llvm/include/llvm/MC/MCTargetAsmParser.h

@@ -18,6 +18,7 @@ class StringRef;
 class SMLoc;
 class AsmToken;
 class MCParsedAsmOperand;
+class MCInst;
 template <typename T> class SmallVectorImpl;
 
 /// MCTargetAsmParser - Generic interface to target specific assembly parsers.
@@ -28,7 +29,8 @@ public:
     Match_InvalidOperand,
     Match_MissingFeature,
     Match_MnemonicFail,
-    Match_Success
+    Match_Success,
+    FIRST_TARGET_MATCH_RESULT_TY
   };
 
 private:
@@ -88,6 +90,12 @@ public:
                           SmallVectorImpl<MCParsedAsmOperand*> &Operands,
                           MCStreamer &Out) = 0;
 
+  /// checkTargetMatchPredicate - Validate the instruction match against
+  /// any complex target predicates not expressible via match classes.
+  virtual unsigned checkTargetMatchPredicate(MCInst &Inst) {
+    return Match_Success;
+  }
+
 };
 
 } // End llvm namespace

llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp

@@ -2981,9 +2981,10 @@ MatchAndEmitInstruction(SMLoc IDLoc,
                         MCStreamer &Out) {
   MCInst Inst;
   unsigned ErrorInfo;
-  MatchResultTy MatchResult;
+  unsigned MatchResult;
   MatchResult = MatchInstructionImpl(Operands, Inst, ErrorInfo);
   switch (MatchResult) {
+  default: break;
   case Match_Success:
     // Context sensitive operand constraints aren't handled by the matcher,
     // so check them here.

llvm/lib/Target/MBlaze/AsmParser/MBlazeAsmParser.cpp

@@ -323,6 +323,7 @@ MatchAndEmitInstruction(SMLoc IDLoc,
   unsigned ErrorInfo;
 
   switch (MatchInstructionImpl(Operands, Inst, ErrorInfo)) {
+  default: break;
   case Match_Success:
     Out.EmitInstruction(Inst);
     return false;

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -981,6 +981,7 @@ MatchAndEmitInstruction(SMLoc IDLoc,
 
   // First, try a direct match.
   switch (MatchInstructionImpl(Operands, Inst, OrigErrorInfo)) {
+  default: break;
   case Match_Success:
     Out.EmitInstruction(Inst);
     return false;
@@ -1019,7 +1020,7 @@ MatchAndEmitInstruction(SMLoc IDLoc,
   // Check for the various suffix matches.
   Tmp[Base.size()] = Suffixes[0];
   unsigned ErrorInfoIgnore;
-  MatchResultTy Match1, Match2, Match3, Match4;
+  unsigned Match1, Match2, Match3, Match4;
   
   Match1 = MatchInstructionImpl(Operands, Inst, ErrorInfoIgnore);
   Tmp[Base.size()] = Suffixes[1];

llvm/utils/TableGen/AsmMatcherEmitter.cpp

@@ -2179,7 +2179,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
      << "                       const SmallVectorImpl<MCParsedAsmOperand*> "
      << "&Operands);\n";
   OS << "  bool MnemonicIsValid(StringRef Mnemonic);\n";
-  OS << "  MatchResultTy MatchInstructionImpl(\n";
+  OS << "  unsigned MatchInstructionImpl(\n";
   OS << "    const SmallVectorImpl<MCParsedAsmOperand*> &Operands,\n";
   OS << "    MCInst &Inst, unsigned &ErrorInfo);\n";
 
@@ -2321,7 +2321,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "}\n\n";
 
   // Finally, build the match function.
-  OS << Target.getName() << ClassName << "::MatchResultTy "
+  OS << "unsigned "
      << Target.getName() << ClassName << "::\n"
      << "MatchInstructionImpl(const SmallVectorImpl<MCParsedAsmOperand*>"
      << " &Operands,\n";
@@ -2348,7 +2348,8 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "  }\n\n";
 
   OS << "  // Some state to try to produce better error messages.\n";
-  OS << "  bool HadMatchOtherThanFeatures = false;\n\n";
+  OS << "  bool HadMatchOtherThanFeatures = false;\n";
+  OS << "  unsigned RetCode = Match_InvalidOperand;\n";
   OS << "  // Set ErrorInfo to the operand that mismatches if it is\n";
   OS << "  // wrong for all instances of the instruction.\n";
   OS << "  ErrorInfo = ~0U;\n";
@@ -2404,6 +2405,17 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "      return Match_ConversionFail;\n";
   OS << "\n";
 
+  // Verify the instruction with the target-specific match predicate function.
+  OS << "    // We have a potential match. Check the target predicate to\n"
+     << "    // handle any context sensitive constraints.\n"
+     << "    unsigned MatchResult;\n"
+     << "    if ((MatchResult = checkTargetMatchPredicate(Inst)) !="
+     << " Match_Success) {\n"
+     << "      Inst.clear();\n"
+     << "      RetCode = MatchResult;\n"
+     << "      continue;\n"
+     << "    }\n\n";
+
   // Call the post-processing function, if used.
   std::string InsnCleanupFn =
     AsmParser->getValueAsString("AsmParserInstCleanup");
@@ -2415,7 +2427,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
 
   OS << "  // Okay, we had no match.  Try to return a useful error code.\n";
   OS << "  if (HadMatchOtherThanFeatures) return Match_MissingFeature;\n";
-  OS << "  return Match_InvalidOperand;\n";
+  OS << "  return RetCode;\n";
   OS << "}\n\n";
 
   if (Info.OperandMatchInfo.size())