From: Bill Wendling <isanbard@gmail.com>
Date: Mon, 23 May 2011 00:18:33 +0000 (+0000)
Subject: Use a more efficient data structure for the "operand map". The number of
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=f415d8b64687d4db7e1986b74e9da6cae72c0fd1;p=oota-llvm.git

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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131886 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/utils/TableGen/AsmWriterEmitter.cpp b/utils/TableGen/AsmWriterEmitter.cpp
index 2b1a4cc8a3d..e6deb6908e0 100644
--- a/utils/TableGen/AsmWriterEmitter.cpp
+++ b/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";