[IR] Share implementation for pairs of const and non-const methods using const_cast. NFCI

llvm-svn: 298830

Author: topperc

llvm/include/llvm/IR/BasicBlock.h

@@ -337,8 +337,11 @@ class BasicBlock : public Value, // Basic blocks are data objects also
   bool isLandingPad() const;
 
   /// \brief Return the landingpad instruction associated with the landing pad.
-  LandingPadInst *getLandingPadInst();
   const LandingPadInst *getLandingPadInst() const;
+  LandingPadInst *getLandingPadInst() {
+    return const_cast<LandingPadInst *>(
+                    static_cast<const BasicBlock *>(this)->getLandingPadInst());
+  }
 
 private:
   /// \brief Increment the internal refcount of the number of BlockAddresses

llvm/include/llvm/IR/Instruction.h

@@ -68,14 +68,20 @@ class Instruction : public User,
   /// Note: this is undefined behavior if the instruction does not have a
   /// parent, or the parent basic block does not have a parent function.
   const Module *getModule() const;
-  Module *getModule();
+  Module *getModule() {
+    return const_cast<Module *>(
+                           static_cast<const Instruction *>(this)->getModule());
+  }
 
   /// Return the function this instruction belongs to.
   ///
   /// Note: it is undefined behavior to call this on an instruction not
   /// currently inserted into a function.
   const Function *getFunction() const;
-  Function *getFunction();
+  Function *getFunction() {
+    return const_cast<Function *>(
+                         static_cast<const Instruction *>(this)->getFunction());
+  }
 
   /// This method unlinks 'this' from the containing basic block, but does not
   /// delete it.

llvm/lib/IR/BasicBlock.cpp

@@ -429,9 +429,6 @@ bool BasicBlock::isLandingPad() const {
 }
 
 /// Return the landingpad instruction associated with the landing pad.
-LandingPadInst *BasicBlock::getLandingPadInst() {
-  return dyn_cast<LandingPadInst>(getFirstNonPHI());
-}
 const LandingPadInst *BasicBlock::getLandingPadInst() const {
   return dyn_cast<LandingPadInst>(getFirstNonPHI());
 }

llvm/lib/IR/Instruction.cpp

@@ -60,12 +60,6 @@ const Module *Instruction::getModule() const {
   return getParent()->getModule();
 }
 
-Module *Instruction::getModule() {
-  return getParent()->getModule();
-}
-
-Function *Instruction::getFunction() { return getParent()->getParent(); }
-
 const Function *Instruction::getFunction() const {
   return getParent()->getParent();
 }