Initial implementation of 'fence' instruction, the new C++0x-style replacement for llvm.memory.barrier.

This is just a LangRef entry and reading/writing/memory representation; optimizer+codegen support coming soon.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136009 91177308-0d34-0410-b5e6-96231b3b80d8

12 files changed, 186 insertions, 1 deletions

diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 29eb944d4a..cdee98bd0c 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -506,6 +506,15 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(deplibs);
   KEYWORD(datalayout);
   KEYWORD(volatile);
+  KEYWORD(atomic);
+  KEYWORD(unordered);
+  KEYWORD(monotonic);
+  KEYWORD(acquire);
+  KEYWORD(release);
+  KEYWORD(acq_rel);
+  KEYWORD(seq_cst);
+  KEYWORD(singlethread);
+
   KEYWORD(nuw);
   KEYWORD(nsw);
   KEYWORD(exact);
@@ -630,6 +639,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   INSTKEYWORD(alloca,      Alloca);
   INSTKEYWORD(load,        Load);
   INSTKEYWORD(store,       Store);
+  INSTKEYWORD(fence,       Fence);
   INSTKEYWORD(getelementptr, GetElementPtr);
 
   INSTKEYWORD(extractelement, ExtractElement);
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 7164ae1ba5..76771c29ba 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1145,6 +1145,32 @@ bool LLParser::ParseOptionalCommaAlign(unsigned &Alignment,
   return false;
 }
 
+/// ParseScopeAndOrdering
+///   if isAtomic: ::= 'singlethread'? AtomicOrdering
+///   else: ::=
+///
+/// This sets Scope and Ordering to the parsed values.
+bool LLParser::ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope,
+                                     AtomicOrdering &Ordering) {
+  if (!isAtomic)
+    return false;
+
+  Scope = CrossThread;
+  if (EatIfPresent(lltok::kw_singlethread))
+    Scope = SingleThread;
+  switch (Lex.getKind()) {
+  default: return TokError("Expected ordering on atomic instruction");
+  case lltok::kw_unordered: Ordering = Unordered; break;
+  case lltok::kw_monotonic: Ordering = Monotonic; break;
+  case lltok::kw_acquire: Ordering = Acquire; break;
+  case lltok::kw_release: Ordering = Release; break;
+  case lltok::kw_acq_rel: Ordering = AcquireRelease; break;
+  case lltok::kw_seq_cst: Ordering = SequentiallyConsistent; break;
+  }
+  Lex.Lex();
+  return false;
+}
+
 /// ParseOptionalStackAlignment
 ///   ::= /* empty */
 ///   ::= 'alignstack' '(' 4 ')'
@@ -2924,6 +2950,7 @@ int LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
   case lltok::kw_alloca:         return ParseAlloc(Inst, PFS);
   case lltok::kw_load:           return ParseLoad(Inst, PFS, false);
   case lltok::kw_store:          return ParseStore(Inst, PFS, false);
+  case lltok::kw_fence:          return ParseFence(Inst, PFS);
   case lltok::kw_volatile:
     if (EatIfPresent(lltok::kw_load))
       return ParseLoad(Inst, PFS, true);
@@ -3633,6 +3660,23 @@ int LLParser::ParseStore(Instruction *&Inst, PerFunctionState &PFS,
   return AteExtraComma ? InstExtraComma : InstNormal;
 }
 
+/// ParseFence
+///   ::= 'fence' 'singlethread'? AtomicOrdering
+int LLParser::ParseFence(Instruction *&Inst, PerFunctionState &PFS) {
+  AtomicOrdering Ordering = NotAtomic;
+  SynchronizationScope Scope = CrossThread;
+  if (ParseScopeAndOrdering(true /*Always atomic*/, Scope, Ordering))
+    return true;
+
+  if (Ordering == Unordered)
+    return TokError("fence cannot be unordered");
+  if (Ordering == Monotonic)
+    return TokError("fence cannot be monotonic");
+
+  Inst = new FenceInst(Context, Ordering, Scope);
+  return InstNormal;
+}
+
 /// ParseGetElementPtr
 ///   ::= 'getelementptr' 'inbounds'? TypeAndValue (',' TypeAndValue)*
 int LLParser::ParseGetElementPtr(Instruction *&Inst, PerFunctionState &PFS) {
diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index 41e42cad19..1eaf3252a8 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -15,6 +15,7 @@
 #define LLVM_ASMPARSER_LLPARSER_H
 
 #include "LLLexer.h"
+#include "llvm/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/DenseMap.h"
@@ -178,6 +179,8 @@ namespace llvm {
     bool ParseOptionalVisibility(unsigned &Visibility);
     bool ParseOptionalCallingConv(CallingConv::ID &CC);
     bool ParseOptionalAlignment(unsigned &Alignment);
+    bool ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope,
+                               AtomicOrdering &Ordering);
     bool ParseOptionalStackAlignment(unsigned &Alignment);
     bool ParseOptionalCommaAlign(unsigned &Alignment, bool &AteExtraComma);
     bool ParseIndexList(SmallVectorImpl<unsigned> &Indices,bool &AteExtraComma);
@@ -360,6 +363,7 @@ namespace llvm {
     int ParseAlloc(Instruction *&I, PerFunctionState &PFS);
     int ParseLoad(Instruction *&I, PerFunctionState &PFS, bool isVolatile);
     int ParseStore(Instruction *&I, PerFunctionState &PFS, bool isVolatile);
+    int ParseFence(Instruction *&I, PerFunctionState &PFS);
     int ParseGetElementPtr(Instruction *&I, PerFunctionState &PFS);
     int ParseExtractValue(Instruction *&I, PerFunctionState &PFS);
     int ParseInsertValue(Instruction *&I, PerFunctionState &PFS);
diff --git a/lib/AsmParser/LLToken.h b/lib/AsmParser/LLToken.h
index a5f89fcce0..bf41c68ffe 100644
--- a/lib/AsmParser/LLToken.h
+++ b/lib/AsmParser/LLToken.h
@@ -53,6 +53,9 @@ namespace lltok {
     kw_deplibs,
     kw_datalayout,
     kw_volatile,
+    kw_atomic,
+    kw_unordered, kw_monotonic, kw_acquire, kw_release, kw_acq_rel, kw_seq_cst,
+    kw_singlethread,
     kw_nuw,
     kw_nsw,
     kw_exact,
@@ -121,7 +124,7 @@ namespace lltok {
     kw_ret, kw_br, kw_switch, kw_indirectbr, kw_invoke, kw_unwind,
     kw_unreachable,
 
-    kw_alloca, kw_load, kw_store, kw_getelementptr,
+    kw_alloca, kw_load, kw_store, kw_fence, kw_getelementptr,
 
     kw_extractelement, kw_insertelement, kw_shufflevector,
     kw_extractvalue, kw_insertvalue, kw_blockaddress,
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 914c6c1051..2029f438b4 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -131,6 +131,27 @@ static int GetDecodedBinaryOpcode(unsigned Val, Type *Ty) {
   }
 }
 
+static AtomicOrdering GetDecodedOrdering(unsigned Val) {
+  switch (Val) {
+  case bitc::ORDERING_NOTATOMIC: return NotAtomic;
+  case bitc::ORDERING_UNORDERED: return Unordered;
+  case bitc::ORDERING_MONOTONIC: return Monotonic;
+  case bitc::ORDERING_ACQUIRE: return Acquire;
+  case bitc::ORDERING_RELEASE: return Release;
+  case bitc::ORDERING_ACQREL: return AcquireRelease;
+  default: // Map unknown orderings to sequentially-consistent.
+  case bitc::ORDERING_SEQCST: return SequentiallyConsistent;
+  }
+}
+
+static SynchronizationScope GetDecodedSynchScope(unsigned Val) {
+  switch (Val) {
+  case bitc::SYNCHSCOPE_SINGLETHREAD: return SingleThread;
+  default: // Map unknown scopes to cross-thread.
+  case bitc::SYNCHSCOPE_CROSSTHREAD: return CrossThread;
+  }
+}
+
 namespace llvm {
 namespace {
   /// @brief A class for maintaining the slot number definition
@@ -2534,6 +2555,18 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
       InstructionList.push_back(I);
       break;
     }
+    case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, synchscope]
+      if (2 != Record.size())
+        return Error("Invalid FENCE record");
+      AtomicOrdering Ordering = GetDecodedOrdering(Record[0]);
+      if (Ordering == NotAtomic || Ordering == Unordered ||
+          Ordering == Monotonic)
+        return Error("Invalid FENCE record");
+      SynchronizationScope SynchScope = GetDecodedSynchScope(Record[1]);
+      I = new FenceInst(Context, Ordering, SynchScope);
+      InstructionList.push_back(I);
+      break;
+    }
     case bitc::FUNC_CODE_INST_CALL: {
       // CALL: [paramattrs, cc, fnty, fnid, arg0, arg1...]
       if (Record.size() < 3)
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 4dfa0ba4df..9df3c17bf4 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -101,6 +101,27 @@ static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
   }
 }
 
+static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
+  switch (Ordering) {
+  default: llvm_unreachable("Unknown atomic ordering");
+  case NotAtomic: return bitc::ORDERING_NOTATOMIC;
+  case Unordered: return bitc::ORDERING_UNORDERED;
+  case Monotonic: return bitc::ORDERING_MONOTONIC;
+  case Acquire: return bitc::ORDERING_ACQUIRE;
+  case Release: return bitc::ORDERING_RELEASE;
+  case AcquireRelease: return bitc::ORDERING_ACQREL;
+  case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
+  }
+}
+
+static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
+  switch (SynchScope) {
+  default: llvm_unreachable("Unknown synchronization scope");
+  case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
+  case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
+  }
+}
+
 static void WriteStringRecord(unsigned Code, StringRef Str,
                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
   SmallVector<unsigned, 64> Vals;
@@ -1147,6 +1168,11 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
     Vals.push_back(cast<StoreInst>(I).isVolatile());
     break;
+  case Instruction::Fence:
+    Code = bitc::FUNC_CODE_INST_FENCE;
+    Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
+    Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
+    break;
   case Instruction::Call: {
     const CallInst &CI = cast<CallInst>(I);
     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index ba18465c0d..649a38aff0 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3211,6 +3211,10 @@ void SelectionDAGBuilder::visitStore(const StoreInst &I) {
   DAG.setRoot(StoreNode);
 }
 
+void SelectionDAGBuilder::visitFence(const FenceInst &I) {
+  llvm_unreachable("Not implemented yet");
+}
+
 /// visitTargetIntrinsic - Lower a call of a target intrinsic to an INTRINSIC
 /// node.
 void SelectionDAGBuilder::visitTargetIntrinsic(const CallInst &I,
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index a0884ebf5d..d5d106b427 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -504,6 +504,7 @@ private:
   void visitAlloca(const AllocaInst &I);
   void visitLoad(const LoadInst &I);
   void visitStore(const StoreInst &I);
+  void visitFence(const FenceInst &I);
   void visitPHI(const PHINode &I);
   void visitCall(const CallInst &I);
   bool visitMemCmpCall(const CallInst &I);
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index 1ce0447d80..1f8e89173c 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1098,6 +1098,7 @@ public:
 
   void writeOperand(const Value *Op, bool PrintType);
   void writeParamOperand(const Value *Operand, Attributes Attrs);
+  void writeAtomic(AtomicOrdering Ordering, SynchronizationScope SynchScope);
 
   void writeAllMDNodes();
 
@@ -1128,6 +1129,28 @@ void AssemblyWriter::writeOperand(const Value *Operand, bool PrintType) {
   WriteAsOperandInternal(Out, Operand, &TypePrinter, &Machine, TheModule);
 }
 
+void AssemblyWriter::writeAtomic(AtomicOrdering Ordering,
+                                 SynchronizationScope SynchScope) {
+  if (Ordering == NotAtomic)
+    return;
+
+  switch (SynchScope) {
+  default: Out << " <bad scope " << int(SynchScope) << ">"; break;
+  case SingleThread: Out << " singlethread"; break;
+  case CrossThread: break;
+  }
+
+  switch (Ordering) {
+  default: Out << " <bad ordering " << int(Ordering) << ">"; break;
+  case Unordered: Out << " unordered"; break;
+  case Monotonic: Out << " monotonic"; break;
+  case Acquire: Out << " acquire"; break;
+  case Release: Out << " release"; break;
+  case AcquireRelease: Out << " acq_rel"; break;
+  case SequentiallyConsistent: Out << " seq_cst"; break;
+  }
+}
+
 void AssemblyWriter::writeParamOperand(const Value *Operand,
                                        Attributes Attrs) {
   if (Operand == 0) {
@@ -1883,6 +1906,8 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
     Out << ", align " << cast<LoadInst>(I).getAlignment();
   } else if (isa<StoreInst>(I) && cast<StoreInst>(I).getAlignment()) {
     Out << ", align " << cast<StoreInst>(I).getAlignment();
+  } else if (const FenceInst *FI = dyn_cast<FenceInst>(&I)) {
+    writeAtomic(FI->getOrdering(), FI->getSynchScope());
   }
 
   // Print Metadata info.
diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 4627e7182b..4597b575e8 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -127,6 +127,7 @@ const char *Instruction::getOpcodeName(unsigned OpCode) {
   case Alloca:        return "alloca";
   case Load:          return "load";
   case Store:         return "store";
+  case Fence:         return "fence";
   case GetElementPtr: return "getelementptr";
 
   // Convert instructions...
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 6d27689ca4..ba4dae5c29 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -996,6 +996,26 @@ void StoreInst::setAlignment(unsigned Align) {
 }
 
 //===----------------------------------------------------------------------===//
+//                       FenceInst Implementation
+//===----------------------------------------------------------------------===//
+
+FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
+                     SynchronizationScope SynchScope,
+                     Instruction *InsertBefore)
+  : Instruction(Type::getVoidTy(C), Fence, 0, 0, InsertBefore) {
+  setOrdering(Ordering);
+  setSynchScope(SynchScope);
+}
+
+FenceInst::FenceInst(LLVMContext &C, AtomicOrdering Ordering, 
+                     SynchronizationScope SynchScope,
+                     BasicBlock *InsertAtEnd)
+  : Instruction(Type::getVoidTy(C), Fence, 0, 0, InsertAtEnd) {
+  setOrdering(Ordering);
+  setSynchScope(SynchScope);
+}
+
+//===----------------------------------------------------------------------===//
 //                       GetElementPtrInst Implementation
 //===----------------------------------------------------------------------===//
 
@@ -3018,6 +3038,10 @@ StoreInst *StoreInst::clone_impl() const {
                        isVolatile(), getAlignment());
 }
 
+FenceInst *FenceInst::clone_impl() const {
+  return new FenceInst(getContext(), getOrdering(), getSynchScope());
+}
+
 TruncInst *TruncInst::clone_impl() const {
   return new TruncInst(getOperand(0), getType());
 }
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index c6b14c0567..2b2b815946 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -278,6 +278,7 @@ namespace {
     void visitUserOp1(Instruction &I);
     void visitUserOp2(Instruction &I) { visitUserOp1(I); }
     void visitIntrinsicFunctionCall(Intrinsic::ID ID, CallInst &CI);
+    void visitFenceInst(FenceInst &FI);
     void visitAllocaInst(AllocaInst &AI);
     void visitExtractValueInst(ExtractValueInst &EVI);
     void visitInsertValueInst(InsertValueInst &IVI);
@@ -1315,6 +1316,15 @@ void Verifier::visitAllocaInst(AllocaInst &AI) {
   visitInstruction(AI);
 }
 
+void Verifier::visitFenceInst(FenceInst &FI) {
+  const AtomicOrdering Ordering = FI.getOrdering();
+  Assert1(Ordering == Acquire || Ordering == Release ||
+          Ordering == AcquireRelease || Ordering == SequentiallyConsistent,
+          "fence instructions may only have "
+          " acquire, release, acq_rel, or seq_cst ordering.", &FI);
+  visitInstruction(FI);
+}
+
 void Verifier::visitExtractValueInst(ExtractValueInst &EVI) {
   Assert1(ExtractValueInst::getIndexedType(EVI.getAggregateOperand()->getType(),
                                            EVI.getIndices()) ==