lib/VMCore/IntrinsicInst.cpp

   1 //===-- InstrinsicInst.cpp - Intrinsic Instruction Wrappers -----*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements methods that make it really easy to deal with intrinsic
  11 // functions with the isa/dyncast family of functions.  In particular, this
  12 // allows you to do things like:
  13 //
  14 //     if (DbgStopPointInst *SPI = dyn_cast<DbgStopPointInst>(Inst))
  15 //        ... SPI->getFileName() ... SPI->getDirectory() ...
  16 //
  17 // All intrinsic function calls are instances of the call instruction, so these
  18 // are all subclasses of the CallInst class.  Note that none of these classes
  19 // has state or virtual methods, which is an important part of this gross/neat
  20 // hack working.
  21 //
  22 // In some cases, arguments to intrinsics need to be generic and are defined as
  23 // type pointer to empty struct { }*.  To access the real item of interest the
  24 // cast instruction needs to be stripped away.
  25 //
  26 //===----------------------------------------------------------------------===//
  27
  28 #include "llvm/IntrinsicInst.h"
  29 #include "llvm/Constants.h"
  30 #include "llvm/GlobalVariable.h"
  31 #include "llvm/Analysis/ValueTracking.h"
  32 #include "llvm/CodeGen/MachineModuleInfo.h"
  33 using namespace llvm;
  34
  35 //===----------------------------------------------------------------------===//
  36 /// DbgInfoIntrinsic - This is the common base class for debug info intrinsics
  37 ///
  38
  39 static Value *CastOperand(Value *C) {
  40   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
  41     if (CE->isCast())
  42       return CE->getOperand(0);
  43   return NULL;
  44 }
  45
  46 Value *DbgInfoIntrinsic::StripCast(Value *C) {
  47   if (Value *CO = CastOperand(C)) {
  48     C = StripCast(CO);
  49   } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
  50     if (GV->hasInitializer())
  51       if (Value *CO = CastOperand(GV->getInitializer()))
  52         C = StripCast(CO);
  53   }
  54   return dyn_cast<GlobalVariable>(C);
  55 }
  56
  57 //===----------------------------------------------------------------------===//
  58 /// DbgStopPointInst - This represents the llvm.dbg.stoppoint instruction.
  59 ///
  60
  61 Value *DbgStopPointInst::getFileName() const {
  62   // Once the operand indices are verified, update this assert
  63   assert(LLVMDebugVersion == (7 << 16) && "Verify operand indices");
  64   GlobalVariable *GV = cast<GlobalVariable>(getContext());
  65   if (!GV->hasInitializer()) return NULL;
  66   ConstantStruct *CS = cast<ConstantStruct>(GV->getInitializer());
  67   return CS->getOperand(3);
  68 }
  69
  70 Value *DbgStopPointInst::getDirectory() const {
  71   // Once the operand indices are verified, update this assert
  72   assert(LLVMDebugVersion == (7 << 16) && "Verify operand indices");
  73   GlobalVariable *GV = cast<GlobalVariable>(getContext());
  74   if (!GV->hasInitializer()) return NULL;
  75   ConstantStruct *CS = cast<ConstantStruct>(GV->getInitializer());
  76   return CS->getOperand(4);
  77 }