minix/llvm/passes/magic/support/VariableRefs.cpp

   1 #include <magic/support/VariableRefs.h>
   2
   3 using namespace llvm;
   4
   5 namespace llvm {
   6
   7 //===----------------------------------------------------------------------===//
   8 // Constructors, destructor, and operators
   9 //===----------------------------------------------------------------------===//
  10
  11 VariableRefs::VariableRefs() {
  12     clear();
  13 }
  14
  15 //===----------------------------------------------------------------------===//
  16 // Getters
  17 //===----------------------------------------------------------------------===//
  18
  19 bool VariableRefs::isUnnecessaryInstruction(Instruction* inst) const {
  20     //have already instruction in the entry block, skip
  21     if(instructionInEntryBlock) {
  22         return true;
  23     }
  24     //have already instruction in the same block, skip
  25     if(instruction && inst->getParent() == instruction->getParent()) {
  26         return true;
  27     }
  28
  29     return false;
  30 }
  31
  32 Instruction* VariableRefs::getInstruction() const {
  33     return instruction;
  34 }
  35
  36 bool VariableRefs::isInstructionInEntryBlock() const {
  37     return instructionInEntryBlock;
  38 }
  39
  40 //===----------------------------------------------------------------------===//
  41 // Other public methods
  42 //===----------------------------------------------------------------------===//
  43
  44 void VariableRefs::addInstruction(Instruction* inst) {
  45     //no instruction yet, update instruction
  46     if(!instruction) {
  47         instruction = inst;
  48         return;
  49     }
  50     //have already instruction in another block, give up and resort to a single instruction in the entry block
  51     setFunctionEntryInstruction(inst->getParent()->getParent());
  52 }
  53
  54 void VariableRefs::clear() {
  55     instruction = NULL;
  56     instructionInEntryBlock = false;
  57 }
  58
  59 //===----------------------------------------------------------------------===//
  60 // Private methods
  61 //===----------------------------------------------------------------------===//
  62
  63 void VariableRefs::setFunctionEntryInstruction(Function* function) {
  64     this->instruction = function->front().getFirstNonPHI();
  65     this->instructionInEntryBlock = true;
  66 }
  67
  68 }