Use a more efficient data structure for the "operand map". The number of

operands to an instruction aren't great, so an iterative search is fairly quick
and doesn't have the overhead of std::map.

llvm-svn: 131886

1 files changed, 28 insertions, 7 deletions

diff --git a/llvm/utils/TableGen/AsmWriterEmitter.cpp b/llvm/utils/TableGen/AsmWriterEmitter.cpp
index 2b1a4cc8a3d..e6deb6908e0 100644
--- a/llvm/utils/TableGen/AsmWriterEmitter.cpp
+++ b/llvm/utils/TableGen/AsmWriterEmitter.cpp
@@ -670,8 +670,8 @@ public:
 
     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(6) << "OpMap.push_back(std::make_pair(\"" << I->first << "\", "
+                  << I->second << "));\n";
 
     O.indent(6) << "break;\n";
     O.indent(4) << '}';
@@ -754,6 +754,20 @@ static void EmitComputeAvailableFeatures(AsmWriterInfo &Info,
   O << "}\n\n";
 }
 
+static void EmitGetMapOperandNumber(raw_ostream &O) {
+  O << "static unsigned getMapOperandNumber("
+    << "const SmallVectorImpl<std::pair<StringRef, unsigned> > &OpMap,\n";
+  O << "                                    StringRef Name) {\n";
+  O << "  for (SmallVectorImpl<std::pair<StringRef, unsigned> >::"
+    << "const_iterator\n";
+  O << "         I = OpMap.begin(), E = OpMap.end(); I != E; ++I)\n";
+  O << "    if (I->first == Name)\n";
+  O << "      return I->second;\n";
+  O << "  assert(false && \"Operand not in map!\");\n";
+  O << "  return 0;\n";
+  O << "}\n\n";
+}
+
 void AsmWriterEmitter::EmitRegIsInRegClass(raw_ostream &O) {
   CodeGenTarget Target(Records);
 
@@ -934,9 +948,12 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
   EmitSubtargetFeatureFlagEnumeration(AWI, O);
   EmitComputeAvailableFeatures(AWI, AsmWriter, Target, O);
 
-  O << "bool " << Target.getName() << ClassName
-    << "::printAliasInstr(const " << MachineInstrClassName
-    << " *MI, raw_ostream &OS) {\n";
+  std::string Header;
+  raw_string_ostream HeaderO(Header);
+
+  HeaderO << "bool " << Target.getName() << ClassName
+          << "::printAliasInstr(const " << MachineInstrClassName
+          << " *MI, raw_ostream &OS) {\n";
 
   std::string Cases;
   raw_string_ostream CasesO(Cases);
@@ -979,14 +996,18 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
   }
 
   if (CasesO.str().empty() || !isMC) {
+    O << HeaderO.str();
     O << "  return false;\n";
     O << "}\n\n";
     O << "#endif // PRINT_ALIAS_INSTR\n";
     return;
   }
 
+  EmitGetMapOperandNumber(O);
+
+  O << HeaderO.str();
   O.indent(2) << "StringRef AsmString;\n";
-  O.indent(2) << "std::map<StringRef, unsigned> OpMap;\n";
+  O.indent(2) << "SmallVector<std::pair<StringRef, unsigned>, 4> OpMap;\n";
   if (NeedAvailableFeatures)
     O.indent(2) << "unsigned AvailableFeatures = getAvailableFeatures();\n\n";
   O.indent(2) << "switch (MI->getOpcode()) {\n";
@@ -1012,7 +1033,7 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
   O << "                *I == '_'))\n";
   O << "          ++I;\n";
   O << "        StringRef Name(Start, I - Start);\n";
-  O << "        printOperand(MI, OpMap[Name], OS);\n";
+  O << "        printOperand(MI, getMapOperandNumber(OpMap, Name), OS);\n";
   O << "      } else {\n";
   O << "        OS << *I++;\n";
   O << "      }\n";