Initial revision

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2 91177308-0d34-0410-b5e6-96231b3b80d8

lib/VMCore/BasicBlock.cpp

@@ -0,0 +1,113 @@
+//===-- BasicBlock.cpp - Implement BasicBlock related functions --*- C++ -*--=//
+//
+// This file implements the Method class for the VMCore library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ValueHolderImpl.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/iTerminators.h"
+#include "llvm/Module.h"
+#include "llvm/Method.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/Type.h"
+
+// Instantiate Templates - This ugliness is the price we have to pay
+// for having a ValueHolderImpl.h file seperate from ValueHolder.h!  :(
+//
+template class ValueHolder<Instruction, BasicBlock>;
+
+BasicBlock::BasicBlock(const string &name, Method *parent)
+  : Value(Type::LabelTy, Value::BasicBlockVal, name), InstList(this, 0) {
+
+  if (parent)
+    parent->getBasicBlocks().push_back(this);
+}
+
+BasicBlock::~BasicBlock() {
+  dropAllReferences();
+  InstList.delete_all();
+}
+
+// Specialize setName to take care of symbol table majik
+void BasicBlock::setName(const string &name) {
+  Method *P;
+  if ((P = getParent()) && hasName()) P->getSymbolTable()->remove(this);
+  Value::setName(name);
+  if (P && hasName()) P->getSymbolTable()->insert(this);
+}
+
+void BasicBlock::setParent(Method *parent) { 
+  if (getParent() && hasName())
+    getParent()->getSymbolTable()->remove(this);
+
+  InstList.setParent(parent);
+
+  if (getParent() && hasName())
+    getParent()->getSymbolTableSure()->insert(this);
+}
+
+TerminatorInst *BasicBlock::getTerminator() {
+  if (InstList.empty()) return 0;
+  Instruction *T = InstList.back();
+  if (T->isTerminator()) return (TerminatorInst*)T;
+  return 0;
+}
+
+const TerminatorInst *const BasicBlock::getTerminator() const {
+  if (InstList.empty()) return 0;
+  const Instruction *T = InstList.back();
+  if (T->isTerminator()) return (TerminatorInst*)T;
+  return 0;
+}
+
+void BasicBlock::dropAllReferences() {
+  for_each(InstList.begin(), InstList.end(), 
+	   std::mem_fun(&Instruction::dropAllReferences));
+}
+
+// hasConstantPoolReferences() - This predicate is true if there is a 
+// reference to this basic block in the constant pool for this method.  For
+// example, if a block is reached through a switch table, that table resides
+// in the constant pool, and the basic block is reference from it.
+//
+bool BasicBlock::hasConstantPoolReferences() const {
+  for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I)
+    if ((*I)->getValueType() == ConstantVal)
+      return true;
+
+  return false;
+}
+
+
+// splitBasicBlock - This splits a basic block into two at the specified
+// instruction.  Note that all instructions BEFORE the specified iterator stay
+// as part of the original basic block, an unconditional branch is added to 
+// the new BB, and the rest of the instructions in the BB are moved to the new
+// BB, including the old terminator.  This invalidates the iterator.
+//
+// Note that this only works on well formed basic blocks (must have a 
+// terminator), and 'I' must not be the end of instruction list (which would
+// cause a degenerate basic block to be formed, having a terminator inside of
+// the basic block). 
+//
+BasicBlock *BasicBlock::splitBasicBlock(InstListType::iterator I) {
+  assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!");
+  assert(I != InstList.end() && 
+	 "Trying to get me to create degenerate basic block!");
+
+  BasicBlock *New = new BasicBlock("", getParent());
+
+  // Go from the end of the basic block through to the iterator pointer, moving
+  // to the new basic block...
+  Instruction *Inst = 0;
+  do {
+    InstListType::iterator EndIt = InstList.end();
+    Inst = InstList.remove(--EndIt);                  // Remove from end
+    New->InstList.push_front(Inst);                   // Add to front
+  } while (Inst != *I);   // Loop until we move the specified instruction.
+
+  // Add a branch instruction to the newly formed basic block.
+  InstList.push_back(new BranchInst(New));
+  return New;
+}