1 files changed, 213 insertions, 0 deletions
diff --git a/lib/Bytecode/Reader/InstructionReader.cpp b/lib/Bytecode/Reader/InstructionReader.cpp
new file mode 100644
index 0000000000..667e144673
--- /dev/null
+++ b/lib/Bytecode/Reader/InstructionReader.cpp
@@ -0,0 +1,213 @@
+//===- ReadInst.cpp - Code to read an instruction from bytecode -------------===
+//
+// This file defines the mechanism to read an instruction from a bytecode 
+// stream.
+//
+// Note that this library should be as fast as possible, reentrant, and 
+// threadsafe!!
+//
+// TODO: Change from getValue(Raw.Arg1) etc, to getArg(Raw, 1)
+//       Make it check type, so that casts are checked.
+//
+//===------------------------------------------------------------------------===
+
+#include "llvm/iOther.h"
+#include "llvm/iTerminators.h"
+#include "llvm/iMemory.h"
+#include "llvm/DerivedTypes.h"
+#include "ReaderInternals.h"
+
+bool BytecodeParser::ParseRawInst(const uchar *&Buf, const uchar *EndBuf, 
+				  RawInst &Result) {
+  unsigned Op, Typ;
+  if (read(Buf, EndBuf, Op)) return true;
+
+  Result.NumOperands =  Op >> 30;
+  Result.Opcode      = (Op >> 24) & 63;
+
+  switch (Result.NumOperands) {
+  case 1:
+    Result.Ty   = getType((Op >> 12) & 4095);
+    Result.Arg1 = Op & 4095;
+    if (Result.Arg1 == 4095)    // Handle special encoding for 0 operands...
+      Result.NumOperands = 0;
+    break;
+  case 2:
+    Result.Ty   = getType((Op >> 16) & 255);
+    Result.Arg1 = (Op >> 8 ) & 255;
+    Result.Arg2 = (Op >> 0 ) & 255;
+    break;
+  case 3:
+    Result.Ty   = getType((Op >> 18) & 63);
+    Result.Arg1 = (Op >> 12) & 63;
+    Result.Arg2 = (Op >> 6 ) & 63;
+    Result.Arg3 = (Op >> 0 ) & 63;
+    break;
+  case 0:
+    Buf -= 4;  // Hrm, try this again...
+    if (read_vbr(Buf, EndBuf, Result.Opcode)) return true;
+    if (read_vbr(Buf, EndBuf, Typ)) return true;
+    Result.Ty = getType(Typ);
+    if (read_vbr(Buf, EndBuf, Result.NumOperands)) return true;
+
+    switch (Result.NumOperands) {
+    case 0: 
+      cerr << "Zero Arg instr found!\n"; 
+      return true;  // This encoding is invalid!
+    case 1: 
+      if (read_vbr(Buf, EndBuf, Result.Arg1)) return true;
+      break;
+    case 2:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+      break;
+    case 3:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2) ||
+	  read_vbr(Buf, EndBuf, Result.Arg3)) return true;
+      break;
+    default:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+
+      // Allocate a vector to hold arguments 3, 4, 5, 6 ...
+      Result.VarArgs = new vector<unsigned>(Result.NumOperands-2);
+      for (unsigned a = 0; a < Result.NumOperands-2; a++)
+	if (read_vbr(Buf, EndBuf, (*Result.VarArgs)[a])) return true;
+      break;
+    }
+    if (align32(Buf, EndBuf)) return true;
+    break;
+  }
+
+  //cerr << "NO: "  << Result.NumOperands   << " opcode: " << Result.Opcode 
+  //   << " Ty: " << Result.Ty->getName() << " arg1: "   << Result.Arg1 << endl;
+  return false;
+}
+
+
+bool BytecodeParser::ParseInstruction(const uchar *&Buf, const uchar *EndBuf,
+				      Instruction *&Res) {
+  RawInst Raw;
+  if (ParseRawInst(Buf, EndBuf, Raw)) return true;;
+
+  if (Raw.Opcode >= Instruction::FirstUnaryOp && 
+      Raw.Opcode <  Instruction::NumUnaryOps  && Raw.NumOperands == 1) {
+    Res = Instruction::getUnaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1));
+    return false;
+  } else if (Raw.Opcode >= Instruction::FirstBinaryOp &&
+	     Raw.Opcode <  Instruction::NumBinaryOps  && Raw.NumOperands == 2) {
+    Res = Instruction::getBinaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1),
+					 getValue(Raw.Ty, Raw.Arg2));
+    return false;
+  } else if (Raw.Opcode == Instruction::PHINode) {
+    PHINode *PN = new PHINode(Raw.Ty);
+    switch (Raw.NumOperands) {
+    case 0: cerr << "Invalid phi node encountered!\n"; 
+            delete PN; 
+	    return true;
+    case 1: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); break;
+    case 2: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg2)); break;
+    case 3: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg2)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg3)); break;
+    default:
+      PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+      PN->addIncoming(getValue(Raw.Ty, Raw.Arg2));
+      {
+        vector<unsigned> &args = *Raw.VarArgs;
+        for (unsigned i = 0; i < args.size(); i++)
+          PN->addIncoming(getValue(Raw.Ty, args[i]));
+      }
+      delete Raw.VarArgs;
+    }
+    Res = PN;
+    return false;
+  } else if (Raw.Opcode == Instruction::Ret) {
+    if (Raw.NumOperands == 0) {
+      Res = new ReturnInst(); return false; 
+    } else if (Raw.NumOperands == 1) {
+      Res = new ReturnInst(getValue(Raw.Ty, Raw.Arg1)); return false; 
+    }
+  } else if (Raw.Opcode == Instruction::Br) {
+    if (Raw.NumOperands == 1) {
+      Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1));
+      return false;
+    } else if (Raw.NumOperands == 3) {
+      Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1),
+			   (BasicBlock*)getValue(Type::LabelTy, Raw.Arg2),
+			                getValue(Type::BoolTy , Raw.Arg3));
+      return false;
+    }
+  } else if (Raw.Opcode == Instruction::Switch) {
+    SwitchInst *I = 
+      new SwitchInst(getValue(Raw.Ty, Raw.Arg1), 
+                     (BasicBlock*)getValue(Type::LabelTy, Raw.Arg2));
+    Res = I;
+    if (Raw.NumOperands < 3) return false;  // No destinations?  Wierd.
+
+    if (Raw.NumOperands == 3 || Raw.VarArgs->size() & 1) {
+      cerr << "Switch statement with odd number of arguments!\n";
+      delete I;
+      return true;
+    }      
+    
+    vector<unsigned> &args = *Raw.VarArgs;
+    for (unsigned i = 0; i < args.size(); i += 2)
+      I->dest_push_back((ConstPoolVal*)getValue(Raw.Ty, args[i]),
+                        (BasicBlock*)getValue(Type::LabelTy, args[i+1]));
+
+    delete Raw.VarArgs;
+    return false;
+  } else if (Raw.Opcode == Instruction::Call) {
+    Method *M = (Method*)getValue(Raw.Ty, Raw.Arg1);
+    if (M == 0) return true;
+
+    const MethodType::ParamTypes &PL = M->getMethodType()->getParamTypes();
+    MethodType::ParamTypes::const_iterator It = PL.begin();
+
+    vector<Value *> Params;
+    switch (Raw.NumOperands) {
+    case 0: cerr << "Invalid call instruction encountered!\n";
+	    return true;
+    case 1: break;
+    case 2: Params.push_back(getValue(*It++, Raw.Arg2)); break;
+    case 3: Params.push_back(getValue(*It++, Raw.Arg2)); 
+            if (It == PL.end()) return true;
+            Params.push_back(getValue(*It++, Raw.Arg3)); break;
+    default:
+      Params.push_back(getValue(*It++, Raw.Arg2));
+      {
+        vector<unsigned> &args = *Raw.VarArgs;
+        for (unsigned i = 0; i < args.size(); i++) {
+	  if (It == PL.end()) return true;
+          Params.push_back(getValue(*It++, args[i]));
+	}
+      }
+      delete Raw.VarArgs;
+    }
+    if (It != PL.end()) return true;
+
+    Res = new CallInst(M, Params);
+    return false;
+  } else if (Raw.Opcode == Instruction::Malloc) {
+    if (Raw.NumOperands > 2) return true;
+    Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
+    Res = new MallocInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
+    return false;
+  } else if (Raw.Opcode == Instruction::Alloca) {
+    if (Raw.NumOperands > 2) return true;
+    Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
+    Res = new AllocaInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
+    return false;
+  } else if (Raw.Opcode == Instruction::Free) {
+    Value *Val = getValue(Raw.Ty, Raw.Arg1);
+    if (!Val->getType()->isPointerType()) return true;
+    Res = new FreeInst(Val);
+    return false;
+  }
+
+  cerr << "Unrecognized instruction! " << Raw.Opcode << endl;
+  return true;
+}