Import LLVM, at r72732.

1 files changed, 347 insertions, 0 deletions

diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
new file mode 100644
index 0000000..8002a36
--- /dev/null
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -0,0 +1,347 @@
+//===-- ValueEnumerator.cpp - Number values and types for bitcode writer --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ValueEnumerator class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ValueEnumerator.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/MDNode.h"
+#include "llvm/Module.h"
+#include "llvm/TypeSymbolTable.h"
+#include "llvm/ValueSymbolTable.h"
+#include "llvm/Instructions.h"
+#include <algorithm>
+using namespace llvm;
+
+static bool isSingleValueType(const std::pair<const llvm::Type*,
+                              unsigned int> &P) {
+  return P.first->isSingleValueType();
+}
+
+static bool isIntegerValue(const std::pair<const Value*, unsigned> &V) {
+  return isa<IntegerType>(V.first->getType());
+}
+
+static bool CompareByFrequency(const std::pair<const llvm::Type*,
+                               unsigned int> &P1,
+                               const std::pair<const llvm::Type*,
+                               unsigned int> &P2) {
+  return P1.second > P2.second;
+}
+
+/// ValueEnumerator - Enumerate module-level information.
+ValueEnumerator::ValueEnumerator(const Module *M) {
+  // Enumerate the global variables.
+  for (Module::const_global_iterator I = M->global_begin(),
+         E = M->global_end(); I != E; ++I)
+    EnumerateValue(I);
+
+  // Enumerate the functions.
+  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
+    EnumerateValue(I);
+    EnumerateAttributes(cast<Function>(I)->getAttributes());
+  }
+
+  // Enumerate the aliases.
+  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
+       I != E; ++I)
+    EnumerateValue(I);
+  
+  // Remember what is the cutoff between globalvalue's and other constants.
+  unsigned FirstConstant = Values.size();
+  
+  // Enumerate the global variable initializers.
+  for (Module::const_global_iterator I = M->global_begin(),
+         E = M->global_end(); I != E; ++I)
+    if (I->hasInitializer())
+      EnumerateValue(I->getInitializer());
+
+  // Enumerate the aliasees.
+  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
+       I != E; ++I)
+    EnumerateValue(I->getAliasee());
+  
+  // Enumerate types used by the type symbol table.
+  EnumerateTypeSymbolTable(M->getTypeSymbolTable());
+
+  // Insert constants that are named at module level into the slot pool so that
+  // the module symbol table can refer to them...
+  EnumerateValueSymbolTable(M->getValueSymbolTable());
+  
+  // Enumerate types used by function bodies and argument lists.
+  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
+    
+    for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
+         I != E; ++I)
+      EnumerateType(I->getType());
+    
+    for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+      for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
+        for (User::const_op_iterator OI = I->op_begin(), E = I->op_end(); 
+             OI != E; ++OI)
+          EnumerateOperandType(*OI);
+        EnumerateType(I->getType());
+        if (const CallInst *CI = dyn_cast<CallInst>(I))
+          EnumerateAttributes(CI->getAttributes());
+        else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
+          EnumerateAttributes(II->getAttributes());
+      }
+  }
+  
+  // Optimize constant ordering.
+  OptimizeConstants(FirstConstant, Values.size());
+    
+  // Sort the type table by frequency so that most commonly used types are early
+  // in the table (have low bit-width).
+  std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);
+    
+  // Partition the Type ID's so that the single-value types occur before the
+  // aggregate types.  This allows the aggregate types to be dropped from the
+  // type table after parsing the global variable initializers.
+  std::partition(Types.begin(), Types.end(), isSingleValueType);
+
+  // Now that we rearranged the type table, rebuild TypeMap.
+  for (unsigned i = 0, e = Types.size(); i != e; ++i)
+    TypeMap[Types[i].first] = i+1;
+}
+
+// Optimize constant ordering.
+namespace {
+  struct CstSortPredicate {
+    ValueEnumerator &VE;
+    explicit CstSortPredicate(ValueEnumerator &ve) : VE(ve) {}
+    bool operator()(const std::pair<const Value*, unsigned> &LHS,
+                    const std::pair<const Value*, unsigned> &RHS) {
+      // Sort by plane.
+      if (LHS.first->getType() != RHS.first->getType())
+        return VE.getTypeID(LHS.first->getType()) < 
+               VE.getTypeID(RHS.first->getType());
+      // Then by frequency.
+      return LHS.second > RHS.second;
+    }
+  };
+}
+
+/// OptimizeConstants - Reorder constant pool for denser encoding.
+void ValueEnumerator::OptimizeConstants(unsigned CstStart, unsigned CstEnd) {
+  if (CstStart == CstEnd || CstStart+1 == CstEnd) return;
+  
+  CstSortPredicate P(*this);
+  std::stable_sort(Values.begin()+CstStart, Values.begin()+CstEnd, P);
+  
+  // Ensure that integer constants are at the start of the constant pool.  This
+  // is important so that GEP structure indices come before gep constant exprs.
+  std::partition(Values.begin()+CstStart, Values.begin()+CstEnd,
+                 isIntegerValue);
+  
+  // Rebuild the modified portion of ValueMap.
+  for (; CstStart != CstEnd; ++CstStart)
+    ValueMap[Values[CstStart].first] = CstStart+1;
+}
+
+
+/// EnumerateTypeSymbolTable - Insert all of the types in the specified symbol
+/// table.
+void ValueEnumerator::EnumerateTypeSymbolTable(const TypeSymbolTable &TST) {
+  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end(); 
+       TI != TE; ++TI)
+    EnumerateType(TI->second);
+}
+
+/// EnumerateValueSymbolTable - Insert all of the values in the specified symbol
+/// table into the values table.
+void ValueEnumerator::EnumerateValueSymbolTable(const ValueSymbolTable &VST) {
+  for (ValueSymbolTable::const_iterator VI = VST.begin(), VE = VST.end(); 
+       VI != VE; ++VI)
+    EnumerateValue(VI->getValue());
+}
+
+void ValueEnumerator::EnumerateValue(const Value *V) {
+  assert(V->getType() != Type::VoidTy && "Can't insert void values!");
+  
+  // Check to see if it's already in!
+  unsigned &ValueID = ValueMap[V];
+  if (ValueID) {
+    // Increment use count.
+    Values[ValueID-1].second++;
+    return;
+  }
+
+  // Enumerate the type of this value.
+  EnumerateType(V->getType());
+  
+  if (const Constant *C = dyn_cast<Constant>(V)) {
+    if (isa<GlobalValue>(C)) {
+      // Initializers for globals are handled explicitly elsewhere.
+    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
+      // Do not enumerate the initializers for an array of simple characters.
+      // The initializers just polute the value table, and we emit the strings
+      // specially.
+    } else if (C->getNumOperands()) {
+      // If a constant has operands, enumerate them.  This makes sure that if a
+      // constant has uses (for example an array of const ints), that they are
+      // inserted also.
+      
+      // We prefer to enumerate them with values before we enumerate the user
+      // itself.  This makes it more likely that we can avoid forward references
+      // in the reader.  We know that there can be no cycles in the constants
+      // graph that don't go through a global variable.
+      for (User::const_op_iterator I = C->op_begin(), E = C->op_end();
+           I != E; ++I)
+        EnumerateValue(*I);
+      
+      // Finally, add the value.  Doing this could make the ValueID reference be
+      // dangling, don't reuse it.
+      Values.push_back(std::make_pair(V, 1U));
+      ValueMap[V] = Values.size();
+      return;
+    } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
+      for (MDNode::const_elem_iterator I = N->elem_begin(), E = N->elem_end();
+           I != E; ++I) {
+        if (*I)
+          EnumerateValue(*I);
+        else
+          EnumerateType(Type::VoidTy);
+      }
+
+      Values.push_back(std::make_pair(V, 1U));
+      ValueMap[V] = Values.size();
+      return;
+    }
+  }
+  
+  // Add the value.
+  Values.push_back(std::make_pair(V, 1U));
+  ValueID = Values.size();
+}
+
+
+void ValueEnumerator::EnumerateType(const Type *Ty) {
+  unsigned &TypeID = TypeMap[Ty];
+  
+  if (TypeID) {
+    // If we've already seen this type, just increase its occurrence count.
+    Types[TypeID-1].second++;
+    return;
+  }
+  
+  // First time we saw this type, add it.
+  Types.push_back(std::make_pair(Ty, 1U));
+  TypeID = Types.size();
+  
+  // Enumerate subtypes.
+  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
+       I != E; ++I)
+    EnumerateType(*I);
+}
+
+// Enumerate the types for the specified value.  If the value is a constant,
+// walk through it, enumerating the types of the constant.
+void ValueEnumerator::EnumerateOperandType(const Value *V) {
+  EnumerateType(V->getType());
+  if (const Constant *C = dyn_cast<Constant>(V)) {
+    // If this constant is already enumerated, ignore it, we know its type must
+    // be enumerated.
+    if (ValueMap.count(V)) return;
+
+    // This constant may have operands, make sure to enumerate the types in
+    // them.
+    for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
+      EnumerateOperandType(C->getOperand(i));
+
+    if (const MDNode *N = dyn_cast<MDNode>(V)) {
+      for (unsigned i = 0, e = N->getNumElements(); i != e; ++i)
+        EnumerateOperandType(N->getElement(i));
+    }
+  }
+}
+
+void ValueEnumerator::EnumerateAttributes(const AttrListPtr &PAL) {
+  if (PAL.isEmpty()) return;  // null is always 0.
+  // Do a lookup.
+  unsigned &Entry = AttributeMap[PAL.getRawPointer()];
+  if (Entry == 0) {
+    // Never saw this before, add it.
+    Attributes.push_back(PAL);
+    Entry = Attributes.size();
+  }
+}
+
+
+/// PurgeAggregateValues - If there are any aggregate values at the end of the
+/// value list, remove them and return the count of the remaining values.  If
+/// there are none, return -1.
+int ValueEnumerator::PurgeAggregateValues() {
+  // If there are no aggregate values at the end of the list, return -1.
+  if (Values.empty() || Values.back().first->getType()->isSingleValueType())
+    return -1;
+  
+  // Otherwise, remove aggregate values...
+  while (!Values.empty() && !Values.back().first->getType()->isSingleValueType())
+    Values.pop_back();
+  
+  // ... and return the new size.
+  return Values.size();
+}
+
+void ValueEnumerator::incorporateFunction(const Function &F) {
+  NumModuleValues = Values.size();
+  
+  // Adding function arguments to the value table.
+  for(Function::const_arg_iterator I = F.arg_begin(), E = F.arg_end();
+      I != E; ++I)
+    EnumerateValue(I);
+
+  FirstFuncConstantID = Values.size();
+  
+  // Add all function-level constants to the value table.
+  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
+      for (User::const_op_iterator OI = I->op_begin(), E = I->op_end(); 
+           OI != E; ++OI) {
+        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
+            isa<InlineAsm>(*OI))
+          EnumerateValue(*OI);
+      }
+    BasicBlocks.push_back(BB);
+    ValueMap[BB] = BasicBlocks.size();
+  }
+  
+  // Optimize the constant layout.
+  OptimizeConstants(FirstFuncConstantID, Values.size());
+  
+  // Add the function's parameter attributes so they are available for use in
+  // the function's instruction.
+  EnumerateAttributes(F.getAttributes());
+
+  FirstInstID = Values.size();
+  
+  // Add all of the instructions.
+  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
+      if (I->getType() != Type::VoidTy)
+        EnumerateValue(I);
+    }
+  }
+}
+
+void ValueEnumerator::purgeFunction() {
+  /// Remove purged values from the ValueMap.
+  for (unsigned i = NumModuleValues, e = Values.size(); i != e; ++i)
+    ValueMap.erase(Values[i].first);
+  for (unsigned i = 0, e = BasicBlocks.size(); i != e; ++i)
+    ValueMap.erase(BasicBlocks[i]);
+    
+  Values.resize(NumModuleValues);
+  BasicBlocks.clear();
+}
+