[Asm] Add debug tracing in table-generated assembly matcher

This adds debug tracing to the table-generated assembly instruction matcher,
enabled by the -debug-only=asm-matcher option.

The changes in the target AsmParsers are to add an MCInstrInfo reference under
a consistent name, so that we can use it from table-generated code. This was
already being used this way for targets that use deprecation warnings, but 5
targets did not have it, and Hexagon had it under a different name to the other
backends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315445 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/MC/MCParser/MCTargetAsmParser.h b/include/llvm/MC/MCParser/MCTargetAsmParser.h
index 94da918f01c9d9709a1bbd09b2d7ceff8c3ce9c5..9f8550c3887c8ef395c59bb2d5e1771274c76ef6 100644 (file)
--- a/include/llvm/MC/MCParser/MCTargetAsmParser.h
+++ b/include/llvm/MC/MCParser/MCTargetAsmParser.h
@@ -12,6 +12,7 @@
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
 #include "llvm/MC/MCParser/MCAsmParserExtension.h"
 #include "llvm/MC/MCTargetOptions.h"
@@ -278,7 +279,8 @@ public:
   };
 
 protected: // Can only create subclasses.
-  MCTargetAsmParser(MCTargetOptions const &, const MCSubtargetInfo &STI);
+  MCTargetAsmParser(MCTargetOptions const &, const MCSubtargetInfo &STI,
+                    const MCInstrInfo &MII);
 
   /// Create a copy of STI and return a non-const reference to it.
   MCSubtargetInfo &copySTI();
@@ -299,6 +301,8 @@ protected: // Can only create subclasses.
   /// Current STI.
   const MCSubtargetInfo *STI;
 
+  const MCInstrInfo &MII;
+
 public:
   MCTargetAsmParser(const MCTargetAsmParser &) = delete;
   MCTargetAsmParser &operator=(const MCTargetAsmParser &) = delete;

diff --git a/lib/MC/MCParser/MCTargetAsmParser.cpp b/lib/MC/MCParser/MCTargetAsmParser.cpp
index 64ac82a6c66f37b457150db09f6d9e2e0df69b44..a0c06c9d501894cbf43c0125310aea9855dac8bc 100644 (file)
--- a/lib/MC/MCParser/MCTargetAsmParser.cpp
+++ b/lib/MC/MCParser/MCTargetAsmParser.cpp
@@ -13,8 +13,9 @@
 using namespace llvm;
 
 MCTargetAsmParser::MCTargetAsmParser(MCTargetOptions const &MCOptions,
-                                     const MCSubtargetInfo &STI)
-  : MCOptions(MCOptions), STI(&STI) {}
+                                     const MCSubtargetInfo &STI,
+                                     const MCInstrInfo &MII)
+    : MCOptions(MCOptions), STI(&STI), MII(MII) {}
 
 MCTargetAsmParser::~MCTargetAsmParser() = default;
 

diff --git a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index 3ba7a692039ba45ba49e5a5cf569dcf3dfabbab1..9f49e67ced4c00bc1217d067fd585f433fc39b42 100644 (file)
--- a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -139,7 +139,7 @@ public:
 
   AArch64AsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                    const MCInstrInfo &MII, const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, STI) {
+    : MCTargetAsmParser(Options, STI, MII) {
     IsILP32 = Options.getABIName() == "ilp32";
     MCAsmParserExtension::Initialize(Parser);
     MCStreamer &S = getParser().getStreamer();

diff --git a/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp b/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
index fa7157bb645138c8a7ead732554d00db8658040c..73889e6b8af68a7f57fd427851489179b7213249 100644 (file)
--- a/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ b/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -807,7 +807,6 @@ public:
 };
 
 class AMDGPUAsmParser : public MCTargetAsmParser {
-  const MCInstrInfo &MII;
   MCAsmParser &Parser;
 
   unsigned ForcedEncodingSize = 0;
@@ -855,7 +854,7 @@ public:
   AMDGPUAsmParser(const MCSubtargetInfo &STI, MCAsmParser &_Parser,
                const MCInstrInfo &MII,
                const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, STI), MII(MII), Parser(_Parser) {
+      : MCTargetAsmParser(Options, STI, MII), Parser(_Parser) {
     MCAsmParserExtension::Initialize(Parser);
 
     if (getFeatureBits().none()) {

diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 3792e10e3eb46696d28bff8f8d110da516fb4d6a..1e6c175e41d04e92393f0dd99a4698a3d782c65d 100644 (file)
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -168,7 +168,6 @@ public:
 };
 
 class ARMAsmParser : public MCTargetAsmParser {
-  const MCInstrInfo &MII;
   const MCRegisterInfo *MRI;
   UnwindContext UC;
 
@@ -581,7 +580,7 @@ public:
 
   ARMAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                const MCInstrInfo &MII, const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, STI), MII(MII), UC(Parser) {
+    : MCTargetAsmParser(Options, STI, MII), UC(Parser) {
     MCAsmParserExtension::Initialize(Parser);
 
     // Cache the MCRegisterInfo.

diff --git a/lib/Target/AVR/AsmParser/AVRAsmParser.cpp b/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
index 5004736365c7b7d51296865ca5be1288cfde6c04..2e1adcc6a4fa12133ae15704a010e13e5e1aa73f 100644 (file)
--- a/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
+++ b/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
@@ -83,7 +83,7 @@ class AVRAsmParser : public MCTargetAsmParser {
 public:
   AVRAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                const MCInstrInfo &MII, const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, STI), STI(STI), Parser(Parser) {
+      : MCTargetAsmParser(Options, STI, MII), STI(STI), Parser(Parser) {
     MCAsmParserExtension::Initialize(Parser);
     MRI = getContext().getRegisterInfo();
 

diff --git a/lib/Target/BPF/AsmParser/BPFAsmParser.cpp b/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
index 9e251d211d21ed869a3d0defe8bee6bd25253e42..deaa11325809bb5cce83407099db2c07a82f0447 100644 (file)
--- a/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
+++ b/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
@@ -28,6 +28,7 @@ namespace {
 struct BPFOperand;
 
 class BPFAsmParser : public MCTargetAsmParser {
+
   SMLoc getLoc() const { return getParser().getTok().getLoc(); }
 
   bool PreMatchCheck(OperandVector &Operands);
@@ -68,7 +69,7 @@ public:
 
   BPFAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                const MCInstrInfo &MII, const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, STI) {
+      : MCTargetAsmParser(Options, STI, MII) {
     setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
   }
 };

diff --git a/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp b/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
index d901abbd16925bf644b2a0725bae5e7ebc194b47..d0d8b39b83bc21752069749844a991b9127d9283 100644 (file)
--- a/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
+++ b/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
@@ -96,7 +96,6 @@ class HexagonAsmParser : public MCTargetAsmParser {
 
   MCAsmParser &Parser;
   MCAssembler *Assembler;
-  MCInstrInfo const &MCII;
   MCInst MCB;
   bool InBrackets;
 
@@ -155,8 +154,8 @@ class HexagonAsmParser : public MCTargetAsmParser {
 public:
   HexagonAsmParser(const MCSubtargetInfo &_STI, MCAsmParser &_Parser,
                    const MCInstrInfo &MII, const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, _STI), Parser(_Parser),
-      MCII (MII), MCB(HexagonMCInstrInfo::createBundle()), InBrackets(false) {
+    : MCTargetAsmParser(Options, _STI, MII), Parser(_Parser),
+      MCB(HexagonMCInstrInfo::createBundle()), InBrackets(false) {
     setAvailableFeatures(ComputeAvailableFeatures(getSTI().getFeatureBits()));
 
     MCAsmParserExtension::Initialize(_Parser);
@@ -462,9 +461,9 @@ bool HexagonAsmParser::finishBundle(SMLoc IDLoc, MCStreamer &Out) {
   MCB.setLoc(IDLoc);
   // Check the bundle for errors.
   const MCRegisterInfo *RI = getContext().getRegisterInfo();
-  HexagonMCChecker Check(getContext(), MCII, getSTI(), MCB, *RI);
+  HexagonMCChecker Check(getContext(), MII, getSTI(), MCB, *RI);
 
-  bool CheckOk = HexagonMCInstrInfo::canonicalizePacket(MCII, getSTI(),
+  bool CheckOk = HexagonMCInstrInfo::canonicalizePacket(MII, getSTI(),
                                                         getContext(), MCB,
                                                         &Check);
 
@@ -608,7 +607,7 @@ bool HexagonAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                           MatchingInlineAsm))
     return true;
   HexagonMCInstrInfo::extendIfNeeded(
-      getParser().getContext(), MCII, MCB, *SubInst);
+      getParser().getContext(), MII, MCB, *SubInst);
   MCB.addOperand(MCOperand::createInst(SubInst));
   if (!InBrackets)
     return finishBundle(IDLoc, Out);

diff --git a/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp b/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
index 1394ac7210f2f35a4506826a706e5aa9161bbead..3f24c3ef390208a4c9c6b0d974d66c3faa7275fe 100644 (file)
--- a/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
+++ b/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
@@ -36,7 +36,7 @@
 #include <cstdint>
 #include <memory>
 
-namespace llvm {
+using namespace llvm;
 
 // Auto-generated by TableGen
 static unsigned MatchRegisterName(StringRef Name);
@@ -85,7 +85,7 @@ class LanaiAsmParser : public MCTargetAsmParser {
 public:
   LanaiAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                  const MCInstrInfo &MII, const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, STI), Parser(Parser),
+      : MCTargetAsmParser(Options, STI, MII), Parser(Parser),
         Lexer(Parser.getLexer()), SubtargetInfo(STI) {
     setAvailableFeatures(
         ComputeAvailableFeatures(SubtargetInfo.getFeatureBits()));
@@ -1226,5 +1226,3 @@ bool LanaiAsmParser::ParseInstruction(ParseInstructionInfo & /*Info*/,
 extern "C" void LLVMInitializeLanaiAsmParser() {
   RegisterMCAsmParser<LanaiAsmParser> x(getTheLanaiTarget());
 }
-
-} // end namespace llvm

diff --git a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index 4d6fb7f1cdf96e39b1a449110bd0c2508456e33e..59f78ed5cd63f74712f5f8e6b8b13a9ce69ed528 100644 (file)
--- a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -473,7 +473,7 @@ public:
 
   MipsAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
                 const MCInstrInfo &MII, const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, sti),
+    : MCTargetAsmParser(Options, sti, MII),
         ABI(MipsABIInfo::computeTargetABI(Triple(sti.getTargetTriple()),
                                           sti.getCPU(), Options)) {
     MCAsmParserExtension::Initialize(parser);

diff --git a/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp b/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
index 98be18b10998f07230f7fd6b016b2ab7fc4c5349..2fbf51007c3df2ee5f23d54f4f0804bb4d7f5ea3 100644 (file)
--- a/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
+++ b/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
@@ -251,7 +251,6 @@ namespace {
 struct PPCOperand;
 
 class PPCAsmParser : public MCTargetAsmParser {
-  const MCInstrInfo &MII;
   bool IsPPC64;
   bool IsDarwin;
 
@@ -298,7 +297,7 @@ class PPCAsmParser : public MCTargetAsmParser {
 public:
   PPCAsmParser(const MCSubtargetInfo &STI, MCAsmParser &,
                const MCInstrInfo &MII, const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, STI), MII(MII) {
+    : MCTargetAsmParser(Options, STI, MII) {
     // Check for 64-bit vs. 32-bit pointer mode.
     const Triple &TheTriple = STI.getTargetTriple();
     IsPPC64 = (TheTriple.getArch() == Triple::ppc64 ||

diff --git a/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index b0db5f4d8fbd00dd5c5c1e3d7671360eea8e5aa7..c907f6d3c84ebf184025f126dd2458e6815a7d7e 100644 (file)
--- a/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -30,6 +30,7 @@ namespace {
 struct RISCVOperand;
 
 class RISCVAsmParser : public MCTargetAsmParser {
+
   SMLoc getLoc() const { return getParser().getTok().getLoc(); }
 
   bool generateImmOutOfRangeError(OperandVector &Operands, uint64_t ErrorInfo,
@@ -72,7 +73,7 @@ public:
 
   RISCVAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                  const MCInstrInfo &MII, const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, STI) {
+      : MCTargetAsmParser(Options, STI, MII) {
     setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
   }
 };

diff --git a/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp b/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
index 087c037614a9d23b4fef2c8e9dcf4e43b3b440b0..05f78a48badfcf4ade1863cb4409f6d93414a8e1 100644 (file)
--- a/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
+++ b/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
@@ -108,7 +108,7 @@ public:
   SparcAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
                 const MCInstrInfo &MII,
                 const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, sti), Parser(parser) {
+      : MCTargetAsmParser(Options, sti, MII), Parser(parser) {
     // Initialize the set of available features.
     setAvailableFeatures(ComputeAvailableFeatures(getSTI().getFeatureBits()));
   }

diff --git a/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp b/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
index 33680789ee082ead2034c861c48d3d14be880b6a..1cc01af509c3ac1f857d982f7cf77ba1cdfda10e 100644 (file)
--- a/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
+++ b/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
@@ -425,7 +425,7 @@ public:
   SystemZAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
                    const MCInstrInfo &MII,
                    const MCTargetOptions &Options)
-    : MCTargetAsmParser(Options, sti), Parser(parser) {
+    : MCTargetAsmParser(Options, sti, MII), Parser(parser) {
     MCAsmParserExtension::Initialize(Parser);
 
     // Alias the .word directive to .short.

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 112af623b4a906c18853d936a09f13c03b48103c..22ad3cbd3eb4f99a13c07cce5c2004d63a8ce46a 100644 (file)
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -68,7 +68,6 @@ static const char OpPrecedence[] = {
 };
 
 class X86AsmParser : public MCTargetAsmParser {
-  const MCInstrInfo &MII;
   ParseInstructionInfo *InstInfo;
   std::unique_ptr<X86AsmInstrumentation> Instrumentation;
   bool Code16GCC;
@@ -923,7 +922,7 @@ public:
 
   X86AsmParser(const MCSubtargetInfo &sti, MCAsmParser &Parser,
                const MCInstrInfo &mii, const MCTargetOptions &Options)
-      : MCTargetAsmParser(Options, sti), MII(mii), InstInfo(nullptr),
+      : MCTargetAsmParser(Options, sti, mii),  InstInfo(nullptr),
         Code16GCC(false) {
 
     // Initialize the set of available features.

diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 60ec8c3eef256b5a0e77d7a210d96778a4385f71..a345b19024eb85ce8260b5d9ab184977d5b91921 100644 (file)
--- a/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/utils/TableGen/AsmMatcherEmitter.cpp
@@ -2856,6 +2856,26 @@ static void emitMnemonicSpellChecker(raw_ostream &OS, CodeGenTarget &Target,
 }
 
 
+// Emit a function mapping match classes to strings, for debugging.
+static void emitMatchClassKindNames(std::forward_list<ClassInfo> &Infos,
+                                    raw_ostream &OS) {
+  OS << "#ifndef NDEBUG\n";
+  OS << "const char *getMatchClassName(MatchClassKind Kind) {\n";
+  OS << "  switch (Kind) {\n";
+
+  OS << "  case InvalidMatchClass: return \"InvalidMatchClass\";\n";
+  OS << "  case OptionalMatchClass: return \"OptionalMatchClass\";\n";
+  for (const auto &CI : Infos) {
+    OS << "  case " << CI.Name << ": return \"" << CI.Name << "\";\n";
+  }
+  OS << "  case NumMatchClassKinds: return \"NumMatchClassKinds\";\n";
+
+  OS << "  }\n";
+  OS << "  llvm_unreachable(\"unhandled MatchClassKind!\");\n";
+  OS << "}\n\n";
+  OS << "#endif // NDEBUG\n";
+}
+
 void AsmMatcherEmitter::run(raw_ostream &OS) {
   CodeGenTarget Target(Records);
   Record *AsmParser = Target.getAsmParser();
@@ -3023,6 +3043,8 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   // Emit the routine to validate an operand against a match class.
   emitValidateOperandClass(Info, OS);
 
+  emitMatchClassKindNames(Info.Classes, OS);
+
   // Emit the available features compute function.
   SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
       Info.Target.getName(), ClassName, "ComputeAvailableFeatures",
@@ -3133,6 +3155,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
 
   emitMnemonicSpellChecker(OS, Target, VariantCount);
 
+  OS << "#include \"llvm/Support/Debug.h\"\n";
+  OS << "#include \"llvm/Support/Format.h\"\n\n";
+
   // Finally, build the match function.
   OS << "unsigned " << Target.getName() << ClassName << "::\n"
      << "MatchInstructionImpl(const OperandVector &Operands,\n";
@@ -3214,6 +3239,10 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
           "std::equal_range(Start, End, Mnemonic.lower(), LessOpcode());\n\n";
   }
 
+  OS << "  DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"AsmMatcher: found \" <<\n"
+     << "  std::distance(MnemonicRange.first, MnemonicRange.second) << \n"
+     << "  \" encodings with mnemonic '\" << Mnemonic << \"'\\n\");\n\n";
+
   OS << "  // Return a more specific error code if no mnemonics match.\n";
   OS << "  if (MnemonicRange.first == MnemonicRange.second)\n";
   OS << "    return Match_MnemonicFail;\n\n";
@@ -3222,6 +3251,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
      << "*ie = MnemonicRange.second;\n";
   OS << "       it != ie; ++it) {\n";
 
+  OS << "    DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Trying to match opcode \"\n";
+  OS << "                                          << MII.getName(it->Opcode) << \"\\n\");\n";
+
   if (ReportMultipleNearMisses) {
     OS << "    // Some state to record ways in which this instruction did not match.\n";
     OS << "    NearMissInfo OperandNearMiss = NearMissInfo::getSuccess();\n";
@@ -3247,20 +3279,35 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
      << "; FormalIdx != " << MaxNumOperands << "; ++FormalIdx) {\n";
   OS << "      auto Formal = "
      << "static_cast<MatchClassKind>(it->Classes[FormalIdx]);\n";
+  OS << "      DEBUG_WITH_TYPE(\"asm-matcher\",\n";
+  OS << "                      dbgs() << \"  Matching formal operand class \" << getMatchClassName(Formal)\n";
+  OS << "                             << \" against actual operand at index \" << ActualIdx);\n";
+  OS << "      if (ActualIdx < Operands.size())\n";
+  OS << "        DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \" (\";\n";
+  OS << "                        Operands[ActualIdx]->print(dbgs()); dbgs() << \"): \");\n";
+  OS << "      else\n";
+  OS << "        DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \": \");\n";
   OS << "      if (ActualIdx >= Operands.size()) {\n";
+  OS << "        DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"actual operand index out of range \");\n";
   if (ReportMultipleNearMisses) {
     OS << "        bool ThisOperandValid = (Formal == " <<"InvalidMatchClass) || "
                                    "isSubclass(Formal, OptionalMatchClass);\n";
     OS << "        if (!ThisOperandValid) {\n";
     OS << "          if (!OperandNearMiss) {\n";
     OS << "            // Record info about match failure for later use.\n";
+    OS << "            DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"recording too-few-operands near miss\\n\");\n";
     OS << "            OperandNearMiss =\n";
     OS << "                NearMissInfo::getTooFewOperands(Formal, it->Opcode);\n";
     OS << "          } else {\n";
     OS << "            // If more than one operand is invalid, give up on this match entry.\n";
+    OS << "            DEBUG_WITH_TYPE(\n";
+    OS << "                \"asm-matcher\",\n";
+    OS << "                dbgs() << \"second invalid operand, giving up on this opcode\\n\");\n";
     OS << "            MultipleInvalidOperands = true;\n";
     OS << "            break;\n";
     OS << "          }\n";
+    OS << "        } else {\n";
+    OS << "          DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"but formal operand not required\\n\");\n";
     OS << "        }\n";
     OS << "        continue;\n";
   } else {
@@ -3276,6 +3323,8 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "      MCParsedAsmOperand &Actual = *Operands[ActualIdx];\n";
   OS << "      unsigned Diag = validateOperandClass(Actual, Formal);\n";
   OS << "      if (Diag == Match_Success) {\n";
+  OS << "        DEBUG_WITH_TYPE(\"asm-matcher\",\n";
+  OS << "                        dbgs() << \"match success using generic matcher\\n\");\n";
   OS << "        ++ActualIdx;\n";
   OS << "        continue;\n";
   OS << "      }\n";
@@ -3284,6 +3333,8 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   OS << "      if (Diag != Match_Success) {\n";
   OS << "        unsigned TargetDiag = validateTargetOperandClass(Actual, Formal);\n";
   OS << "        if (TargetDiag == Match_Success) {\n";
+  OS << "          DEBUG_WITH_TYPE(\"asm-matcher\",\n";
+  OS << "                          dbgs() << \"match success using target matcher\\n\");\n";
   OS << "          ++ActualIdx;\n";
   OS << "          continue;\n";
   OS << "        }\n";
@@ -3299,6 +3350,7 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   if (HasOptionalOperands) {
     OS << "        OptionalOperandsMask.set(FormalIdx);\n";
   }
+    OS << "        DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"ignoring optional operand\\n\");\n";
   OS << "        continue;\n";
   OS << "      }\n";
 
@@ -3306,11 +3358,19 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "      if (!OperandNearMiss) {\n";
     OS << "        // If this is the first invalid operand we have seen, record some\n";
     OS << "        // information about it.\n";
+    OS << "        DEBUG_WITH_TYPE(\n";
+    OS << "            \"asm-matcher\",\n";
+    OS << "            dbgs()\n";
+    OS << "                << \"operand match failed, recording near-miss with diag code \"\n";
+    OS << "                << Diag << \"\\n\");\n";
     OS << "        OperandNearMiss =\n";
     OS << "            NearMissInfo::getMissedOperand(Diag, Formal, it->Opcode, ActualIdx);\n";
     OS << "        ++ActualIdx;\n";
     OS << "      } else {\n";
     OS << "        // If more than one operand is invalid, give up on this match entry.\n";
+    OS << "        DEBUG_WITH_TYPE(\n";
+    OS << "            \"asm-matcher\",\n";
+    OS << "            dbgs() << \"second operand mismatch, skipping this opcode\\n\");\n";
     OS << "        MultipleInvalidOperands = true;\n";
     OS << "        break;\n";
     OS << "      }\n";
@@ -3334,9 +3394,14 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
   }
 
   if (ReportMultipleNearMisses)
-    OS << "    if (MultipleInvalidOperands) continue;\n\n";
+    OS << "    if (MultipleInvalidOperands) {\n";
   else
-    OS << "    if (!OperandsValid) continue;\n\n";
+    OS << "    if (!OperandsValid) {\n";
+  OS << "      DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Opcode result: multiple \"\n";
+  OS << "                                               \"operand mismatches, ignoring \"\n";
+  OS << "                                               \"this opcode\\n\");\n";
+  OS << "      continue;\n";
+  OS << "    }\n";
 
   // Emit check that the required features are available.
   OS << "    if ((AvailableFeatures & it->RequiredFeatures) "
@@ -3345,6 +3410,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "      HadMatchOtherThanFeatures = true;\n";
   OS << "      uint64_t NewMissingFeatures = it->RequiredFeatures & "
         "~AvailableFeatures;\n";
+  OS << "      DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Missing target features: \"\n";
+  OS << "                                            << format_hex(NewMissingFeatures, 18)\n";
+  OS << "                                            << \"\\n\");\n";
   if (ReportMultipleNearMisses) {
     OS << "      FeaturesNearMiss = NearMissInfo::getMissedFeature(NewMissingFeatures);\n";
   } else {
@@ -3369,6 +3437,10 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
      << "    if ((MatchResult = checkEarlyTargetMatchPredicate(Inst, "
         "Operands)) != Match_Success) {\n"
      << "      Inst.clear();\n";
+  OS << "      DEBUG_WITH_TYPE(\n";
+  OS << "          \"asm-matcher\",\n";
+  OS << "          dbgs() << \"Early target match predicate failed with diag code \"\n";
+  OS << "                 << MatchResult << \"\\n\");\n";
   if (ReportMultipleNearMisses) {
     OS << "      EarlyPredicateNearMiss = NearMissInfo::getMissedPredicate(MatchResult);\n";
   } else {
@@ -3384,7 +3456,15 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "    if (OperandNearMiss) {\n";
     OS << "      // If the operand mismatch was the only problem, reprrt it as a near-miss.\n";
     OS << "      if (NearMisses && !FeaturesNearMiss && !EarlyPredicateNearMiss) {\n";
+    OS << "        DEBUG_WITH_TYPE(\n";
+    OS << "            \"asm-matcher\",\n";
+    OS << "            dbgs()\n";
+    OS << "                << \"Opcode result: one mismatched operand, adding near-miss\\n\");\n";
     OS << "        NearMisses->push_back(OperandNearMiss);\n";
+    OS << "      } else {\n";
+    OS << "        DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Opcode result: multiple \"\n";
+    OS << "                                                 \"types of mismatch, so not \"\n";
+    OS << "                                                 \"reporting near-miss\\n\");\n";
     OS << "      }\n";
     OS << "      continue;\n";
     OS << "    }\n\n";
@@ -3409,6 +3489,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
      << "    // handle any context sensitive constraints.\n"
      << "    if ((MatchResult = checkTargetMatchPredicate(Inst)) !="
      << " Match_Success) {\n"
+     << "      DEBUG_WITH_TYPE(\"asm-matcher\",\n"
+     << "                      dbgs() << \"Target match predicate failed with diag code \"\n"
+     << "                             << MatchResult << \"\\n\");\n"
      << "      Inst.clear();\n";
   if (ReportMultipleNearMisses) {
     OS << "      LatePredicateNearMiss = NearMissInfo::getMissedPredicate(MatchResult);\n";
@@ -3427,6 +3510,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "    if (NumNearMisses == 1) {\n";
     OS << "      // We had exactly one type of near-miss, so add that to the list.\n";
     OS << "      assert(!OperandNearMiss && \"OperandNearMiss was handled earlier\");\n";
+    OS << "      DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Opcode result: found one type of \"\n";
+    OS << "                                            \"mismatch, so reporting a \"\n";
+    OS << "                                            \"near-miss\\n\");\n";
     OS << "      if (NearMisses && FeaturesNearMiss)\n";
     OS << "        NearMisses->push_back(FeaturesNearMiss);\n";
     OS << "      else if (NearMisses && EarlyPredicateNearMiss)\n";
@@ -3437,6 +3523,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "      continue;\n";
     OS << "    } else if (NumNearMisses > 1) {\n";
     OS << "      // This instruction missed in more than one way, so ignore it.\n";
+    OS << "      DEBUG_WITH_TYPE(\"asm-matcher\", dbgs() << \"Opcode result: multiple \"\n";
+    OS << "                                               \"types of mismatch, so not \"\n";
+    OS << "                                               \"reporting near-miss\\n\");\n";
     OS << "      continue;\n";
     OS << "    }\n";
   }
@@ -3457,6 +3546,9 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
     OS << "    }\n";
   }
 
+  OS << "    DEBUG_WITH_TYPE(\n";
+  OS << "        \"asm-matcher\",\n";
+  OS << "        dbgs() << \"Opcode result: complete match, selecting this opcode\\n\");\n";
   OS << "    return Match_Success;\n";
   OS << "  }\n\n";