A WIP commit of the InstAlias printing cleanup. This code will soon replace the

code below it. Even though it looks very similar, it will match more precisely
and geneate better functions in the long run.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127991 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/AsmWriterEmitter.cpp

@@ -625,26 +625,28 @@ public:
   unsigned getOpIndex(StringRef Op) { return OpMap[Op]; }
   bool isOpMapped(StringRef Op) { return OpMap.find(Op) != OpMap.end(); }
 
-  void print(raw_ostream &O, bool IncIndent) {
-    unsigned Indent = 8 + (IncIndent ? 7 : 0);
+  void print(raw_ostream &O) {
+    unsigned Indent = 8;
+
+    if (!Conds.empty())
+      O << "if (";
 
     for (std::vector<std::string>::iterator
            I = Conds.begin(), E = Conds.end(); I != E; ++I) {
       if (I != Conds.begin()) {
         O << " &&\n";
         O.indent(Indent);
-      } else {
-        O << "if (";
       }
+
       O << *I;
     }
 
-    if (Conds.begin() != Conds.end())
-      O << " &&\n";
-    else
-      O << "if (";
-
     if (!ReqFeatures.empty()) {
+      if (Conds.begin() != Conds.end())
+        O << " &&\n";
+      else
+        O << "if (";
+
       std::string Req;
       raw_string_ostream ReqO(Req);
 
@@ -659,16 +661,23 @@ public:
         << ReqO.str() << ')';
     }
 
-    O << ") {\n";
-    O.indent(6) << "// " << Result << "\n";
-    O.indent(6) << "AsmString = \"" << AsmString << "\";\n";
+    if (!Conds.empty() || !ReqFeatures.empty()) {
+      O << ") {\n";
+      Indent = 6;
+    } else {
+      Indent = 4;
+    }
+
+    O.indent(Indent) << "// " << Result << "\n";
+    O.indent(Indent) << "AsmString = \"" << AsmString << "\";\n";
 
     for (std::map<StringRef, unsigned>::iterator
            I = OpMap.begin(), E = OpMap.end(); I != E; ++I)
-      O.indent(6) << "OpMap[\"" << I->first << "\"] = "
-                  << I->second << ";\n";
+      O.indent(Indent) << "OpMap[\"" << I->first << "\"] = "
+                       << I->second << ";\n";
 
-    O.indent(4) << '}';
+    if (!Conds.empty() || !ReqFeatures.empty())
+      O.indent(4) << '}';
   }
 
   bool operator==(const IAPrinter &RHS) {
@@ -824,10 +833,6 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
   bool isMC = AsmWriter->getValueAsBit("isMCAsmWriter");
   const char *MachineInstrClassName = isMC ? "MCInst" : "MachineInstr";
 
-  O << "bool " << Target.getName() << ClassName
-    << "::printAliasInstr(const " << MachineInstrClassName
-    << " *MI, raw_ostream &OS) {\n";
-
   std::vector<Record*> AllInstAliases =
     Records.getAllDerivedDefinitions("InstAlias");
 
@@ -842,6 +847,103 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
     AliasMap[getQualifiedName(Op->getDef())].push_back(Alias);
   }
 
+#if 0
+  // A map of which conditions need to be met for each instruction operand
+  // before it can be matched to the mnemonic.
+  std::map<std::string, std::vector<IAPrinter*> > IAPrinterMap;
+  AsmWriterInfo AWI;
+
+  for (std::map<std::string, std::vector<CodeGenInstAlias*> >::iterator
+         I = AliasMap.begin(), E = AliasMap.end(); I != E; ++I) {
+    std::vector<CodeGenInstAlias*> &Aliases = I->second;
+
+    for (std::vector<CodeGenInstAlias*>::iterator
+           II = Aliases.begin(), IE = Aliases.end(); II != IE; ++II) {
+      const CodeGenInstAlias *CGA = *II;
+      IAPrinter *IAP = new IAPrinter(AWI, CGA->Result->getAsString(),
+                                     CGA->AsmString);
+
+      IAP->addReqFeatures(CGA->TheDef->getValueAsListOfDefs("Predicates"));
+
+      unsigned LastOpNo = CGA->ResultInstOperandIndex.size();
+
+      std::string Cond;
+      Cond = std::string("MI->getNumOperands() == ") + llvm::utostr(LastOpNo);
+      IAP->addCond(Cond);
+
+      std::map<StringRef, unsigned> OpMap;
+      bool CantHandle = false;
+
+      for (unsigned i = 0, e = LastOpNo; i != e; ++i) {
+        const CodeGenInstAlias::ResultOperand &RO = CGA->ResultOperands[i];
+
+        switch (RO.Kind) {
+        default: assert(0 && "unexpected InstAlias operand kind");
+        case CodeGenInstAlias::ResultOperand::K_Record: {
+          const Record *Rec = RO.getRecord();
+          StringRef ROName = RO.getName();
+
+          if (Rec->isSubClassOf("RegisterClass")) {
+            Cond = std::string("MI->getOperand(")+llvm::utostr(i)+").isReg()";
+            IAP->addCond(Cond);
+
+            if (!IAP->isOpMapped(ROName)) {
+              IAP->addOperand(ROName, i);
+              Cond = std::string("regIsInRegisterClass(RC_") +
+                CGA->ResultOperands[i].getRecord()->getName() +
+                ", MI->getOperand(" + llvm::utostr(i) + ").getReg())";
+              IAP->addCond(Cond);
+            } else {
+              Cond = std::string("MI->getOperand(") +
+                llvm::utostr(i) + ").getReg() == MI->getOperand(" +
+                llvm::utostr(IAP->getOpIndex(ROName)) + ").getReg()";
+              IAP->addCond(Cond);
+            }
+          } else {
+            assert(Rec->isSubClassOf("Operand") && "Unexpected operand!");
+            // FIXME: We need to handle these situations.
+            delete IAP;
+            IAP = 0;
+            CantHandle = true;
+            break;
+          }
+
+          break;
+        }
+        case CodeGenInstAlias::ResultOperand::K_Imm:
+          Cond = std::string("MI->getOperand(") +
+            llvm::utostr(i) + ").getImm() == " +
+            llvm::utostr(CGA->ResultOperands[i].getImm());
+          IAP->addCond(Cond);
+          break;
+        case CodeGenInstAlias::ResultOperand::K_Reg:
+          Cond = std::string("MI->getOperand(") +
+            llvm::utostr(i) + ").getReg() == " + Target.getName() +
+            "::" + CGA->ResultOperands[i].getRegister()->getName();
+          IAP->addCond(Cond);
+          break;
+        }
+
+        if (!IAP) break;
+      }
+
+      if (CantHandle) continue;
+      IAPrinterMap[I->first].push_back(IAP);
+
+      O.indent(4) << "// " << I->first << '\n';
+      O.indent(4);
+      IAP->print(O);
+    }
+  }
+
+  EmitSubtargetFeatureFlagEnumeration(AWI, O);
+  EmitComputeAvailableFeatures(AWI, AsmWriter, Target, O);
+#endif
+
+  O << "bool " << Target.getName() << ClassName
+    << "::printAliasInstr(const " << MachineInstrClassName
+    << " *MI, raw_ostream &OS) {\n";
+
   if (AliasMap.empty() || !isMC) {
     // FIXME: Support MachineInstr InstAliases?
     O << "  return true;\n";