Support stand alone metadata syntax.

!0 = constant metadata !{i32 21, i32 22}
@llvm.blah = constant metadata !{i32 1000, i16 200, metadata !0}



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74630 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AsmParser/LLParser.cpp

@@ -109,6 +109,7 @@ bool LLParser::ParseTopLevelEntities() {
     case lltok::StringConstant: // FIXME: REMOVE IN LLVM 3.0
     case lltok::LocalVar:   if (ParseNamedType()) return true; break;
     case lltok::GlobalVar:  if (ParseNamedGlobal()) return true; break;
+    case lltok::Metadata:   if (ParseStandaloneMetadata()) return true; break;
 
     // The Global variable production with no name can have many different
     // optional leading prefixes, the production is:
@@ -355,6 +356,34 @@ bool LLParser::ParseNamedGlobal() {
   return ParseAlias(Name, NameLoc, Visibility);
 }
 
+/// ParseStandaloneMetadata:
+///   !42 = !{...} 
+bool LLParser::ParseStandaloneMetadata() {
+  assert(Lex.getKind() == lltok::Metadata);
+  Lex.Lex();
+  unsigned MetadataID = 0;
+  if (ParseUInt32(MetadataID))
+    return true;
+  if (MetadataCache.find(MetadataID) != MetadataCache.end())
+    return TokError("Metadata id is already used");
+  if (ParseToken(lltok::equal, "expected '=' here"))
+    return true;
+
+  LocTy TyLoc;
+  bool IsConstant;    
+  PATypeHolder Ty(Type::VoidTy);
+  if (ParseGlobalType(IsConstant) ||
+      ParseType(Ty, TyLoc))
+    return true;
+  
+  Constant *Init = 0;
+  if (ParseGlobalValue(Ty, Init))
+      return true;
+
+  MetadataCache[MetadataID] = Init;
+  return false;
+}
+
 /// ParseAlias:
 ///   ::= GlobalVar '=' OptionalVisibility 'alias' OptionalLinkage Aliasee
 /// Aliasee
@@ -1596,6 +1625,17 @@ bool LLParser::ParseValID(ValID &ID) {
       return false;
     }
 
+    // Standalone metadata reference
+    // !{ ..., !42, ... }
+    unsigned MID = 0;
+    if (!ParseUInt32(MID)) {
+      std::map<unsigned, Constant *>::iterator I = MetadataCache.find(MID);
+      if (I == MetadataCache.end())
+	return TokError("Unknown metadata reference");
+      ID.ConstantVal = I->second;
+      return false;
+    }
+    
     // MDString:
     //   ::= '!' STRINGCONSTANT
     std::string Str;

lib/AsmParser/LLParser.h

@@ -43,7 +43,8 @@ namespace llvm {
     std::map<std::string, std::pair<PATypeHolder, LocTy> > ForwardRefTypes;
     std::map<unsigned, std::pair<PATypeHolder, LocTy> > ForwardRefTypeIDs;
     std::vector<PATypeHolder> NumberedTypes;
-
+    /// MetadataCache - This map keeps track of parsed metadata constants.
+    std::map<unsigned, Constant *> MetadataCache;
     struct UpRefRecord {
       /// Loc - This is the location of the upref.
       LocTy Loc;
@@ -139,6 +140,7 @@ namespace llvm {
     bool ParseGlobal(const std::string &Name, LocTy Loc, unsigned Linkage,
                      bool HasLinkage, unsigned Visibility);
     bool ParseAlias(const std::string &Name, LocTy Loc, unsigned Visibility);
+    bool ParseStandaloneMetadata();
 
     // Type Parsing.
     bool ParseType(PATypeHolder &Result, bool AllowVoid = false);

lib/VMCore/AsmWriter.cpp

@@ -35,6 +35,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cctype>
+#include <map>
 using namespace llvm;
 
 // Make virtual table appear in this compilation unit.
@@ -945,25 +946,6 @@ static void WriteConstantInt(raw_ostream &Out, const Constant *CV,
     return;
   }
 
-  if (const MDNode *N = dyn_cast<MDNode>(CV)) {
-    Out << "!{";
-    for (MDNode::const_elem_iterator I = N->elem_begin(), E = N->elem_end();
-         I != E;) {
-      if (!*I) {
-        Out << "null";
-      } else {
-        TypePrinter.print((*I)->getType(), Out);
-        Out << ' ';
-        WriteAsOperandInternal(Out, *I, TypePrinter, Machine);
-      }
-
-      if (++I != E)
-        Out << ", ";
-    }
-    Out << "}";
-    return;
-  }
-  
   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
     Out << CE->getOpcodeName();
     if (CE->isCompare())
@@ -1092,10 +1074,14 @@ class AssemblyWriter {
   TypePrinting TypePrinter;
   AssemblyAnnotationWriter *AnnotationWriter;
   std::vector<const Type*> NumberedTypes;
+
+  // Each MDNode is assigned unique MetadataIDNo.
+  std::map<const MDNode *, unsigned> MDNodes;
+  unsigned MetadataIDNo;
 public:
   inline AssemblyWriter(raw_ostream &o, SlotTracker &Mac, const Module *M,
                         AssemblyAnnotationWriter *AAW)
-    : Out(o), Machine(Mac), TheModule(M), AnnotationWriter(AAW) {
+    : Out(o), Machine(Mac), TheModule(M), AnnotationWriter(AAW), MetadataIDNo(0) {
     AddModuleTypesToPrinter(TypePrinter, NumberedTypes, M);
   }
 
@@ -1124,6 +1110,7 @@ private:
   void printModule(const Module *M);
   void printTypeSymbolTable(const TypeSymbolTable &ST);
   void printGlobal(const GlobalVariable *GV);
+  void printMDNode(const MDNode *Node, bool StandAlone);
   void printAlias(const GlobalAlias *GV);
   void printFunction(const Function *F);
   void printArgument(const Argument *FA, Attributes Attrs);
@@ -1264,6 +1251,28 @@ static void PrintVisibility(GlobalValue::VisibilityTypes Vis,
 }
 
 void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
+  if (GV->hasInitializer())
+    // If GV is initialized using Metadata then separate out metadata
+    // operands used by the initializer. Note, MDNodes are not cyclic.
+    if (MDNode *N = dyn_cast<MDNode>(GV->getInitializer())) {
+      SmallVector<const MDNode *, 4> WorkList;
+      // Collect MDNodes used by the initializer.
+      for (MDNode::const_elem_iterator I = N->elem_begin(), E = N->elem_end();
+	   I != E; ++I) {
+	const Value *TV = *I;
+	if (TV)
+	  if (const MDNode *NN = dyn_cast<MDNode>(TV))
+	    WorkList.push_back(NN);
+      }
+
+      // Print MDNodes used by the initializer.
+      while (!WorkList.empty()) {
+	const MDNode *N = WorkList.back(); WorkList.pop_back();
+	printMDNode(N, true);
+	Out << '\n';
+      }
+    }
+
   if (GV->hasName()) {
     PrintLLVMName(Out, GV);
     Out << " = ";
@@ -1283,7 +1292,10 @@ void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
 
   if (GV->hasInitializer()) {
     Out << ' ';
-    writeOperand(GV->getInitializer(), false);
+    if (MDNode *N = dyn_cast<MDNode>(GV->getInitializer()))
+      printMDNode(N, false);
+    else
+      writeOperand(GV->getInitializer(), false);
   }
     
   if (GV->hasSection())
@@ -1295,6 +1307,42 @@ void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
   Out << '\n';
 }
 
+void AssemblyWriter::printMDNode(const MDNode *Node,
+				 bool StandAlone) {
+  std::map<const MDNode *, unsigned>::iterator MI = MDNodes.find(Node);
+  // If this node is already printed then just refer it using its Metadata
+  // id number.
+  if (MI != MDNodes.end()) {
+    Out << "metadata !" << MI->second;
+    return;
+  }
+  
+  if (StandAlone) {
+    // Print standalone MDNode.
+    // !42 = !{ ... }
+    Out << "!" << MetadataIDNo << " = ";
+    Out << "constant metadata ";
+  }
+  Out << "!{";
+  for (MDNode::const_elem_iterator I = Node->elem_begin(), E = Node->elem_end();
+       I != E;) {
+    const Value *TV = *I;
+    if (!TV)
+      Out << "null";
+    else if (const MDNode *N = dyn_cast<MDNode>(TV)) 
+      printMDNode(N, StandAlone);
+    else if (!*I)
+      Out << "null";
+    else 
+      writeOperand(*I, true);
+    if (++I != E)
+      Out << ", ";
+  }
+  Out << "}";
+
+  MDNodes[Node] = MetadataIDNo++;
+}
+
 void AssemblyWriter::printAlias(const GlobalAlias *GA) {
   // Don't crash when dumping partially built GA
   if (!GA->hasName())

test/Feature/mdnode2.ll

@@ -0,0 +1,7 @@
+; RUN: llvm-as < %s | llvm-dis > %t.ll
+; RUN: grep "!0 = constant metadata !{i32 21, i32 22}" %t.ll
+; RUN: grep "!1 = constant metadata !{i32 23, i32 24}" %t.ll
+; RUN: grep "@llvm.blah = constant metadata !{i32 1000, i16 200, metadata !1, metadata !0}" %t.ll
+!0 = constant metadata !{i32 21, i32 22}
+!1 = constant metadata !{i32 23, i32 24}
+@llvm.blah = constant metadata !{i32 1000, i16 200, metadata !1, metadata !0}