Major refactoring of the bytecode reader. This includes the following

changes:
  * BytecodeReader::getType(...) used to return a null pointer
    on error.  This was only checked about half the time.  Now we convert
    it to throw an exception, and delete the half that checked for error.
    This was checked in before, but psmith crashed and lost the change :(
  * insertValue no longer returns -1 on error, so callers don't need to
    check for it.
  * Substantial rewrite of InstructionReader.cpp, to use more efficient,
    simpler, data structures.  This provides another 5% speedup.  This also
    makes the code much easier to read and understand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8984 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 31 deletions

diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index 67726eb..e649cdc 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -49,17 +49,15 @@ unsigned BytecodeParser::getTypeSlot(const Type *Ty) {
 }
 
 const Type *BytecodeParser::getType(unsigned ID) {
-  if (ID < Type::NumPrimitiveIDs) {
-    const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID);
-    if (T) return T;
-  }
+  if (ID < Type::NumPrimitiveIDs)
+    if (const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID))
+      return T;
   
   //cerr << "Looking up Type ID: " << ID << "\n";
 
-  if (ID < Type::NumPrimitiveIDs) {
-    const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID);
-    if (T) return T;   // Asked for a primitive type...
-  }
+  if (ID < Type::NumPrimitiveIDs)
+    if (const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID))
+      return T;   // Asked for a primitive type...
 
   // Otherwise, derived types need offset...
   ID -= FirstDerivedTyID;
@@ -73,10 +71,10 @@ const Type *BytecodeParser::getType(unsigned ID) {
   if (ID < FunctionTypeValues.size())
     return FunctionTypeValues[ID].get();
 
-  return 0;
+  throw std::string("Illegal type reference!");
 }
 
-int BytecodeParser::insertValue(Value *Val, ValueTable &ValueTab) {
+unsigned BytecodeParser::insertValue(Value *Val, ValueTable &ValueTab) {
   assert((!HasImplicitZeroInitializer || !isa<Constant>(Val) ||
           Val->getType()->isPrimitiveType() ||
           !cast<Constant>(Val)->isNullValue()) &&
@@ -200,10 +198,7 @@ BasicBlock *BytecodeParser::ParseBasicBlock(const unsigned char *&Buf,
 
   while (Buf < EndBuf) {
     Instruction *Inst = ParseInstruction(Buf, EndBuf);
-    if (insertValue(Inst, Values) == -1) { 
-      throw std::string("Could not insert value.");
-    }
-
+    insertValue(Inst, Values);
     BB->getInstList().push_back(Inst);
     BCR_TRACE(4, Inst);
   }
@@ -221,9 +216,7 @@ void BytecodeParser::ParseSymbolTable(const unsigned char *&Buf,
     if (read_vbr(Buf, EndBuf, NumEntries) ||
         read_vbr(Buf, EndBuf, Typ)) throw Error_readvbr;
     const Type *Ty = getType(Typ);
-    if (Ty == 0) throw std::string("Invalid type read in symbol table.");
-
-    BCR_TRACE(3, "Plane Type: '" << Ty << "' with " << NumEntries <<
+    BCR_TRACE(3, "Plane Type: '" << *Ty << "' with " << NumEntries <<
                  " entries\n");
 
     for (unsigned i = 0; i < NumEntries; ++i) {
@@ -328,10 +321,8 @@ void BytecodeParser::materializeFunction(Function* F) {
   const FunctionType::ParamTypes &Params =F->getFunctionType()->getParamTypes();
   Function::aiterator AI = F->abegin();
   for (FunctionType::ParamTypes::const_iterator It = Params.begin();
-       It != Params.end(); ++It, ++AI) {
-    if (insertValue(AI, Values) == -1)
-      throw std::string("Error reading function arguments!");
-  }
+       It != Params.end(); ++It, ++AI)
+    insertValue(AI, Values);
 
   // Keep track of how many basic blocks we have read in...
   unsigned BlockNum = 0;
@@ -435,7 +426,7 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     }
 
     const Type *Ty = getType(SlotNo);
-    if (!Ty || !isa<PointerType>(Ty))
+    if (!isa<PointerType>(Ty))
       throw std::string("Global not pointer type!  Ty = " + 
                         Ty->getDescription());
 
@@ -444,10 +435,8 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     // Create the global variable...
     GlobalVariable *GV = new GlobalVariable(ElTy, VarType & 1, Linkage,
                                             0, "", TheModule);
-    int DestSlot = insertValue(GV, ModuleValues);
-    if (DestSlot == -1) throw Error_DestSlot;
     BCR_TRACE(2, "Global Variable of type: " << *Ty << "\n");
-    ResolveReferencesToValue(GV, (unsigned)DestSlot);
+    ResolveReferencesToValue(GV, insertValue(GV, ModuleValues));
 
     if (VarType & 2) { // Does it have an initializer?
       unsigned InitSlot;
@@ -462,11 +451,10 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
   if (read_vbr(Buf, End, FnSignature)) throw Error_readvbr;
   while (FnSignature != Type::VoidTyID) { // List is terminated by Void
     const Type *Ty = getType(FnSignature);
-    if (!Ty || !isa<PointerType>(Ty) ||
-        !isa<FunctionType>(cast<PointerType>(Ty)->getElementType())) { 
+    if (!isa<PointerType>(Ty) ||
+        !isa<FunctionType>(cast<PointerType>(Ty)->getElementType()))
       throw std::string("Function not ptr to func type!  Ty = " +
                         Ty->getDescription());
-    }
 
     // We create functions by passing the underlying FunctionType to create...
     Ty = cast<PointerType>(Ty)->getElementType();
@@ -479,9 +467,8 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     // Insert the placeholder...
     Function *Func = new Function(cast<FunctionType>(Ty),
                                   GlobalValue::InternalLinkage, "", TheModule);
-    int DestSlot = insertValue(Func, ModuleValues);
-    if (DestSlot == -1) throw Error_DestSlot;
-    ResolveReferencesToValue(Func, (unsigned)DestSlot);
+    unsigned DestSlot = insertValue(Func, ModuleValues);
+    ResolveReferencesToValue(Func, DestSlot);
 
     // Keep track of this information in a list that is emptied as functions are
     // loaded...