path: root/lib/CodeGen/CodeGenFunction.h

//===-- CodeGenFunction.h - Per-Function state for LLVM CodeGen -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the internal per-function state used for llvm translation. 
//
//===----------------------------------------------------------------------===//

#ifndef CLANG_CODEGEN_CODEGENFUNCTION_H
#define CLANG_CODEGEN_CODEGENFUNCTION_H

#include "clang/AST/Type.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"

#include <vector>
#include <map>

#include "CGBuilder.h"
#include "CGCall.h"
#include "CGValue.h"

namespace llvm {
  class BasicBlock;
  class Module;
  class SwitchInst;
}

namespace clang {
  class ASTContext;
  class Decl;
  class EnumConstantDecl;
  class FunctionDecl;
  class FunctionTypeProto;
  class LabelStmt;
  class ObjCInterfaceDecl;
  class ObjCIvarDecl;
  class ObjCMethodDecl;
  class ObjCPropertyImplDecl;
  class TargetInfo;
  class VarDecl;

namespace CodeGen {
  class CodeGenModule;
  class CodeGenTypes;
  class CGRecordLayout;  
  
/// CodeGenFunction - This class organizes the per-function state that is used
/// while generating LLVM code.
class CodeGenFunction {
public:
  CodeGenModule &CGM;  // Per-module state.
  TargetInfo &Target;
  
  typedef std::pair<llvm::Value *, llvm::Value *> ComplexPairTy;
  CGBuilderTy Builder;
  
  // Holds the Decl for the current function or method
  const Decl *CurFuncDecl;
  QualType FnRetTy;
  llvm::Function *CurFn;

  /// ReturnBlock - Unified return block.
  llvm::BasicBlock *ReturnBlock;
  /// ReturnValue - The temporary alloca to hold the return value. This
  /// is null iff the function has no return value.
  llvm::Instruction *ReturnValue;
  
  /// AllocaInsertPoint - This is an instruction in the entry block before which
  /// we prefer to insert allocas.
  llvm::Instruction *AllocaInsertPt;

  const llvm::Type *LLVMIntTy;
  uint32_t LLVMPointerWidth;

public:
  // FIXME: The following should be private once EH code is moved out
  // of NeXT runtime.

  // ObjCEHStack - This keeps track of which object to rethrow from
  // inside @catch blocks and which @finally block exits from an EH
  // scope should be chained through.
  struct ObjCEHEntry {
    ObjCEHEntry(llvm::BasicBlock *fb, llvm::BasicBlock *fne, 
                llvm::SwitchInst *fs, llvm::Value *dc)
      : FinallyBlock(fb), FinallyNoExit(fne), FinallySwitch(fs), 
        DestCode(dc), Exception(0) {}

    /// Entry point to the finally block.
    llvm::BasicBlock *FinallyBlock; 

    /// Entry point to the finally block which skips execution of the
    /// try_exit runtime function.
    llvm::BasicBlock *FinallyNoExit; 

    /// Switch instruction which runs at the end of the finally block
    /// to forward jumps through the finally block.
    llvm::SwitchInst *FinallySwitch; 

    /// Variable holding the code for the destination of a jump
    /// through the @finally block.
    llvm::Value *DestCode;

    /// The exception object being handled, during IR generation for a
    /// @catch block.
    llvm::Value *Exception; 
  };

  typedef llvm::SmallVector<ObjCEHEntry*, 8> ObjCEHStackType;
  ObjCEHStackType ObjCEHStack;

  /// EmitJumpThroughFinally - Emit a branch from the current insert
  /// point through the finally handling code for \arg Entry and then
  /// on to \arg Dest.
  ///
  /// \param ExecuteTryExit - When true, the try_exit runtime function
  /// should be called prior to executing the finally code.
  void EmitJumpThroughFinally(ObjCEHEntry *Entry, llvm::BasicBlock *Dest,
                              bool ExecuteTryExit=true);
  
private:
  /// LabelIDs - Track arbitrary ids assigned to labels for use in
  /// implementing the GCC address-of-label extension and indirect
  /// goto. IDs are assigned to labels inside getIDForAddrOfLabel().
  std::map<const LabelStmt*, unsigned> LabelIDs;

  /// IndirectSwitches - Record the list of switches for indirect
  /// gotos. Emission of the actual switching code needs to be delayed
  /// until all AddrLabelExprs have been seen.
  std::vector<llvm::SwitchInst*> IndirectSwitches;

  /// LocalDeclMap - This keeps track of the LLVM allocas or globals for local C
  /// decls.
  llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap;

  /// LabelMap - This keeps track of the LLVM basic block for each C label.
  llvm::DenseMap<const LabelStmt*, llvm::BasicBlock*> LabelMap;
  
  // BreakContinueStack - This keeps track of where break and continue 
  // statements should jump to.
  struct BreakContinue {
    BreakContinue(llvm::BasicBlock *bb, llvm::BasicBlock *cb)
      : BreakBlock(bb), ContinueBlock(cb) {}
      
    llvm::BasicBlock *BreakBlock;
    llvm::BasicBlock *ContinueBlock;
  }; 
  llvm::SmallVector<BreakContinue, 8> BreakContinueStack;

  /// SwitchInsn - This is nearest current switch instruction. It is null if
  /// if current context is not in a switch.
  llvm::SwitchInst *SwitchInsn;

  /// CaseRangeBlock - This block holds if condition check for last case 
  /// statement range in current switch instruction.
  llvm::BasicBlock *CaseRangeBlock;

public:
  CodeGenFunction(CodeGenModule &cgm);
  
  ASTContext &getContext() const;

  void GenerateObjCMethod(const ObjCMethodDecl *OMD);

  void StartObjCMethod(const ObjCMethodDecl *MD);

  /// GenerateObjCGetter - Synthesize an Objective-C property getter
  /// function.
  void GenerateObjCGetter(const ObjCPropertyImplDecl *PID);

  /// GenerateObjCSetter - Synthesize an Objective-C property setter
  /// function for the given property.
  void GenerateObjCSetter(const ObjCPropertyImplDecl *PID);

  void GenerateCode(const FunctionDecl *FD,
                    llvm::Function *Fn);
  void StartFunction(const Decl *D, QualType RetTy, 
                     llvm::Function *Fn,
                     const FunctionArgList &Args,
                     SourceLocation StartLoc);
  void FinishFunction(SourceLocation EndLoc=SourceLocation());

  /// EmitFunctionProlog - Emit the target specific LLVM code to load
  /// the arguments for the given function. This is also responsible
  /// for naming the LLVM function arguments.
  void EmitFunctionProlog(llvm::Function *Fn, QualType RetTy, 
                          const FunctionArgList &Args);

  /// EmitFunctionEpilog - Emit the target specific LLVM code to
  /// return the given temporary.
  void EmitFunctionEpilog(QualType RetTy, 
                          llvm::Value *ReturnValue);

  const llvm::Type *ConvertType(QualType T);

  /// LoadObjCSelf - Load the value of self. This function is only
  /// valid while generating code for an Objective-C method.
  llvm::Value *LoadObjCSelf();

  /// isObjCPointerType - Return true if the specificed AST type will map onto
  /// some Objective-C pointer type.
  static bool isObjCPointerType(QualType T);

  /// hasAggregateLLVMType - Return true if the specified AST type will map into
  /// an aggregate LLVM type or is void.
  static bool hasAggregateLLVMType(QualType T);
  
  /// getBasicBlockForLabel - Return the LLVM basicblock that the specified
  /// label maps to.
  llvm::BasicBlock *getBasicBlockForLabel(const LabelStmt *S);
  
  
  void EmitBlock(llvm::BasicBlock *BB);
  
  /// ErrorUnsupported - Print out an error that codegen doesn't support the
  /// specified stmt yet.
  void ErrorUnsupported(const Stmt *S, const char *Type,
                        bool OmitOnError=false);

  //===--------------------------------------------------------------------===//
  //                                  Helpers
  //===--------------------------------------------------------------------===//
  
  /// CreateTempAlloca - This creates a alloca and inserts it into the entry
  /// block.
  llvm::AllocaInst *CreateTempAlloca(const llvm::Type *Ty,
                                     const char *Name = "tmp");
  
  /// EvaluateExprAsBool - Perform the usual unary conversions on the specified
  /// expression and compare the result against zero, returning an Int1Ty value.
  llvm::Value *EvaluateExprAsBool(const Expr *E);

  /// EmitAnyExpr - Emit code to compute the specified expression which can have
  /// any type.  The result is returned as an RValue struct.  If this is an
  /// aggregate expression, the aggloc/agglocvolatile arguments indicate where
  /// the result should be returned.
  RValue EmitAnyExpr(const Expr *E, llvm::Value *AggLoc = 0, 
                     bool isAggLocVolatile = false);

  /// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result
  /// will always be accessible even if no aggregate location is
  /// provided.
  RValue EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc = 0, 
                           bool isAggLocVolatile = false);

  void EmitAggregateCopy(llvm::Value *DestPtr, llvm::Value *SrcPtr,
                         QualType EltTy);

  void EmitAggregateClear(llvm::Value *DestPtr, QualType Ty);

  /// isDummyBlock - Return true if BB is an empty basic block
  /// with no predecessors.
  static bool isDummyBlock(const llvm::BasicBlock *BB);

  /// StartBlock - Start new block named N. If insert block is a dummy block
  /// then reuse it.
  void StartBlock(const char *N);

  /// getCGRecordLayout - Return record layout info.
  const CGRecordLayout *getCGRecordLayout(CodeGenTypes &CGT, QualType RTy);

  /// GetAddrOfStaticLocalVar - Return the address of a static local variable.
  llvm::Constant *GetAddrOfStaticLocalVar(const VarDecl *BVD);

  /// GetAddrOfLocalVar - Return the address of a local variable.
  llvm::Value *G