path: root/lib/Target/CBackend/CBackend.cpp

//===-- Writer.cpp - Library for converting LLVM code to C ----------------===//
//
// This library converts LLVM code to C code, compilable by GCC.
//
//===-----------------------------------------------------------------------==//
#include "llvm/Assembly/CWriter.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/SymbolTable.h"
#include "llvm/SlotCalculator.h"
#include "llvm/Analysis/FindUsedTypes.h"
#include "llvm/Analysis/ConstantsScanner.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/InstIterator.h"
#include "Support/StringExtras.h"
#include "Support/STLExtras.h"
#include <algorithm>
#include <set>
#include <sstream>
using std::string;
using std::map;
using std::ostream;


namespace {
  class CWriter : public Pass, public InstVisitor<CWriter> {
    ostream &Out; 
    SlotCalculator *Table;
    const Module *TheModule;
    map<const Type *, string> TypeNames;
    std::set<const Value*> MangledGlobals;
    bool needsMalloc;

    map<const ConstantFP *, unsigned> FPConstantMap;
  public:
    CWriter(ostream &o) : Out(o) {}

    void getAnalysisUsage(AnalysisUsage &AU) const {
      AU.setPreservesAll();
      AU.addRequired<FindUsedTypes>();
    }

    virtual bool run(Module &M) {
      // Initialize
      Table = new SlotCalculator(&M, false);
      TheModule = &M;

      // Ensure that all structure types have names...
      bool Changed = nameAllUsedStructureTypes(M);

      // Run...
      printModule(&M);

      // Free memory...
      delete Table;
      TypeNames.clear();
      MangledGlobals.clear();
      return false;
    }

    ostream &printType(std::ostream &Out, const Type *Ty, const string &VariableName = "",
                       bool IgnoreName = false, bool namedContext = true);

    void writeOperand(Value *Operand);
    void writeOperandInternal(Value *Operand);

    string getValueName(const Value *V);

  private :
    bool nameAllUsedStructureTypes(Module &M);
    void printModule(Module *M);
    void printSymbolTable(const SymbolTable &ST);
    void printContainedStructs(const Type *Ty, std::set<const StructType *> &);
    void printGlobal(const GlobalVariable *GV);
    void printFunctionSignature(const Function *F, bool Prototype);

    void printFunction(Function *);

    void printConstant(Constant *CPV);
    void printConstantArray(ConstantArray *CPA);

    // isInlinableInst - Attempt to inline instructions into their uses to build
    // trees as much as possible.  To do this, we have to consistently decide
    // what is acceptable to inline, so that variable declarations don't get
    // printed and an extra copy of the expr is not emitted.
    //
    static bool isInlinableInst(const Instruction &I) {
      // Must be an expression, must be used exactly once.  If it is dead, we
      // emit it inline where it would go.
      if (I.getType() == Type::VoidTy || I.use_size() != 1 ||
          isa<TerminatorInst>(I) || isa<CallInst>(I) || isa<PHINode>(I) || 
          isa<LoadInst>(I)) // Don't inline a load across a store!
        return