coins.casttohir
Class ToHirBaseOpt

java.lang.Object
  coins.casttohir.ToHirVisit
      coins.casttohir.ToHirBaseOpt

public class ToHirBaseOpt

extends ToHirVisit

Do simple HIR-base optimizations such as elimination of useless statements, expansion of control statements with constant conditional expression.

 1. Elimination of useless statements

 Unreachable ExtStmt/return/goto --> eliminate
 Jump to the next statement      --> eliminate
 Unrefered label      --> eliminate
 Successive label     --> combine the labels
 Empty block          --> eliminate
 Expression statement --> eliminate except for side effect part.

 2. Expansion of if-statement

 if(e    ); --> side_effect_of_e;
 if(true ) THEN; else ELSE;
 --> { THEN; goto LABEL_END; ELSE; LABEL_END:; }
 if(false) THEN; else ELSE;
 --> { ELSE; goto LABEL_END; THEN; LABEL_END:; }
 unreachable if(e) THEN; else ELSE;
 --> { goto LABEL_END; THEN; goto LABEL_END; ELSE; LABEL_END:; }

 3. Expansion of while-statement

 while(false) BODY;
 --> { goto LABEL_BREAK; BODY; LABEL_BREAK:; }

 Expansion of for-statement

 for(INIT;false;STEP) BODY;
 --> { INIT; goto LABEL_BREAK; BODY; STEP; LABEL_BREAK:; }

 5. Expansion of do-while statement

 do BODY; while(false); --> BODY;
 unreachable do BODY; while(false);
 --> { goto LABEL_BREAK; BODY; LABEL_BREAK:; }

 6. Expansion of switch statement

 switch(CONST2)
 {
 case CONST1: STMT1;
 case CONST2: STMT2;
 default:     STMT3;
 }
 -->
 {
   goto LABEL_CONST2;
   STMT1;
   LABEL_CONST2:;
   STMT2;
   STMT3;
   LABEL_BREAK:;
 }

 unreachable switch(...)
 {
 case CONST1: STMT1;
 case CONST2: STMT2;
 default:     STMT3;
 }
 -->
 {
   goto LABEL_BREAK;
   STMT1;
   STMT2;
   STMT3;
   LABEL_BREAK:;
 }
 

Field Summary

int	fDbgLevel
protected BlockStmt	nowBlock Now processing block (used to create initializer).

Constructor Summary

ToHirBaseOpt(ToHir tohir)
Constructor.

Method Summary

protected Exp	atAdd(Exp e) At add expression node.
protected Exp	atAddAssign(Exp e) At add-assign expression node.
protected Exp	atAddr(Exp e) At address expression node.
protected Exp	atAnd(Exp e) At and expression node.
protected Exp	atAndAssign(Exp e) At and-assign expression node.
protected Exp	atArrow(Exp e) At arrow expression node.
protected Exp	atARShift(Exp e) At arithmetic R-shift expression node.
protected Exp	atAssign(Exp e) At assign expression node.
protected void	atAssignStmt(AssignStmt s) At assign statement node.
protected void	atBlock(BlockStmt s) At block statement node.
protected Exp	atCall(FunctionExp e) At function call expression node.
protected Exp	atCmpEq(Exp e) At EQ expression node.
protected Exp	atCmpGe(Exp e) At GE expression node.
protected Exp	atCmpGt(Exp e) At GT expression node.
protected Exp	atCmpLe(Exp e) At LE expression node.
protected Exp	atCmpLt(Exp e) At LT expression node.
protected Exp	atCmpNe(Exp e) At NE expression node.
protected Exp	atComma(Exp e) At comma expression node.
protected Exp	atConst(ConstNode e) At constant node.
protected Exp	atContents(Exp e) At indirection expression node.
protected Exp	atConv(Exp e) At cast expression node.
protected Exp	atDecay(Exp e) At decay expression node.
protected Exp	atDiv(Exp e) At div expression node.
protected Exp	atDivAssign(Exp e) At div-assign expression node.
protected Exp	atElem(ElemNode e) At element node.
protected Exp	atEqZero(Exp e) At logical-not expression node.
protected Exp	atExpList(ExpListExp e) At expression list node.
protected Exp	atExpRepeat(Exp e) At expression repeatation node.
protected void	atExpStmt(ExpStmt s) At expression statement node.
protected void	atFor(LoopStmt s) At for statement node.
protected void	atIf(IfStmt s) At if statement node.
protected Exp	atIndex(Exp e) At index expression node.
protected InfStmt	atInfStmt(InfStmt pInf) atInfStmt parses the pragma body in the form of String and change its symbols to instances of Sym (Var, Subp, Label, Const) and items enclosed in parenthesis to IrList changing its elements to Sym, etc.
protected void	atJump(JumpStmt s) At goto statement node.
protected void	atLabeledStmt(LabeledStmt s) At labeled statement node.
protected Exp	atLgAnd(Exp e) At logical-and expression node.
protected Exp	atLgOr(Exp e) At logical-or expression node.
protected Exp	atLShift(Exp e) At L-shift expression node.
protected Exp	atLShiftAssign(Exp e) At L-shift-assign expression node.
protected Exp	atMod(Exp e) At mod expression node.
protected Exp	atModAssign(Exp e) At mod-assign expression node.
protected Exp	atMul(Exp e) At mul expression node.
protected Exp	atMulAssign(Exp e) At mul-assign expression node.
protected Exp	atNeg(Exp e) At negative expression node.
protected Exp	atNot(Exp e) At not expression node.
protected Exp	atOffset(Exp e) At offset(difference of address) expression node.
protected Exp	atOr(Exp e) At or expression node.
protected Exp	atOrAssign(Exp e) At or-assign expression node.
protected Exp	atPost(int op, Exp e) At post-operator expression node.
protected Exp	atPre(int op, Exp e) At pre-operator expression node.
protected Exp	atQual(Exp e) At member-access expression node.
protected void	atReturn(ReturnStmt s) At return statement node.
protected Exp	atRShift(Exp e) At logical R-shift expression node.
protected Exp	atRShiftAssign(Exp e) At R-shift-assign expression node.
protected Exp	atSelect(Exp e) At selection expression node.
protected void	atSetDataStmt(SetDataStmt s) At datacode statement node.
protected Exp	atSub(Exp e) At sub expression node.
protected Exp	atSubAssign(Exp e) At sub-assign expression node.
protected Exp	atSubp(SubpNode e) At function node.
protected SubpDefinition	atSubpDefinition(SubpDefinition s) At block statement node.
protected Exp	atSubs(Exp e) At subscript expression node.
protected void	atSwitch(SwitchStmt s) At switch statement node.
protected Exp	atUndecay(Exp e) At undecay expression node.
protected void	atUntil(LoopStmt s) At do-while statement node.
protected Exp	atVar(VarNode e) At variable node.
protected void	atWhile(LoopStmt s) At while statement node.
protected Exp	atXor(Exp e) At xor expression node.
protected Exp	atXorAssign(Exp e) At xor-assign expression node.
protected boolean	inInitBlock() Return true if now processing in the initialization block.
protected void	message(int level, java.lang.String mes) Output debug message.
(package private) IrList	processPragmaItem(ParseString pParseString, java.lang.String pNextItem, IrList pList)
(package private) Exp	visitExp(Exp e)
void	visitProgram() Visit HIR program tree.
(package private) void	visitProgram(Program program) Visit HIR program tree.
(package private) void	visitStmt(Stmt s) Call appropriate method by operator of statement node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

nowBlock

protected BlockStmt nowBlock

Now processing block (used to create initializer).

fDbgLevel

public final int fDbgLevel

Constructor Detail

ToHirBaseOpt

public ToHirBaseOpt(ToHir tohir)

Constructor.

Parameters:

tohir - Offers cooperation with the object of other packages.

Method Detail

message

protected void message(int level,
                       java.lang.String mes)

Output debug message.

Overrides:

message in class ToHirVisit

Parameters:

level - Debug level.

mes - Debug message.

atBlock

protected void atBlock(BlockStmt s)

At block statement node.

Overrides:

atBlock in class ToHirVisit

Parameters:

s - BlockStmt

atLabeledStmt

protected void atLabeledStmt(LabeledStmt s)

At labeled statement node.

Overrides:

atLabeledStmt in class ToHirVisit

Parameters:

s - LabeledStmt

atAssignStmt

protected void atAssignStmt(AssignStmt s)

At assign statement node.

Overrides:

atAssignStmt in class ToHirVisit

Parameters:

s - AssignStmt

atIf

protected void atIf(IfStmt s)

At if statement node.

Overrides:

atIf in class ToHirVisit

Parameters:

s - IfStmt

atWhile

protected void atWhile(LoopStmt s)

At while statement node.

Overrides:

atWhile in class ToHirVisit

Parameters:

s - LoopStmt

atFor

protected void atFor(LoopStmt s)

At for statement node.

Overrides:

atFor in class ToHirVisit

Parameters:

s - LoopStmt

atUntil

protected void atUntil(LoopStmt s)

At do-while statement node.

Overrides:

atUntil in class ToHirVisit

Parameters:

s - LoopStmt

atJump

protected void atJump(JumpStmt s)

At goto statement node.

Overrides:

atJump in class ToHirVisit

Parameters:

s - JumpStmt

atSwitch

protected void atSwitch(SwitchStmt s)

At switch statement node.

Overrides:

atSwitch in class ToHirVisit

Parameters:

s - SwitchStmt

atReturn

protected void atReturn(ReturnStmt s)

At return statement node.

Overrides:

atReturn in class ToHirVisit

Parameters:

s - ReturnStmt

atExpStmt

protected void atExpStmt(ExpStmt s)

At expression statement node.

Overrides:

atExpStmt in class ToHirVisit

Parameters:

s - ExpStmt

inInitBlock

protected boolean inInitBlock()

Return true if now processing in the initialization block.

Returns:

boolean

visitProgram

public final void visitProgram()

Visit HIR program tree.

visitProgram

final void visitProgram(Program program)

Visit HIR program tree.

Parameters:

program - Program

visitStmt

final void visitStmt(Stmt s)

Call appropriate method by operator of statement node.

Parameters:

s - Visited statement.

atSetDataStmt

protected void atSetDataStmt(SetDataStmt s)

At datacode statement node.

Parameters:

s - SetDataStmt

visitExp

final Exp visitExp(Exp e)

atConst

protected Exp atConst(ConstNode e)

At constant node.

Parameters:

e - Exp

Returns:

Exp

atVar

protected Exp atVar(VarNode e)

At variable node.

Parameters:

e - Exp

Returns:

Exp

atSubp

protected Exp atSubp(SubpNode e)

At function node.

Parameters:

e - Exp

Returns:

Exp

atElem

protected Exp atElem(ElemNode e)

At element node.

Parameters:

e - Exp

Returns:

Exp

atSubs

protected Exp atSubs(Exp e)

At subscript expression node.

Parameters:

e - Exp

Returns:

Exp

atIndex

protected Exp atIndex(Exp e)

At index expression node.

Parameters:

e - Exp

Returns:

Exp

atQual

protected Exp atQual(Exp e)

At member-access expression node.

Parameters:

e - Exp

Returns:

Exp

atArrow

protected Exp atArrow(Exp e)

At arrow expression node.

Parameters:

e - Exp

Returns:

Exp

atCall

protected Exp atCall(FunctionExp e)

At function call expression node.

Parameters:

e - Exp

Returns:

Exp

atAdd

protected Exp atAdd(Exp e)

At add expression node.

Parameters:

e - Exp

Returns:

Exp

atSub

protected Exp atSub(Exp e)

At sub expression node.

Parameters:

e - Exp

Returns:

Exp

atMul

protected Exp atMul(Exp e)

At mul expression node.

Parameters:

e - Exp

Returns:

Exp

atDiv

protected Exp atDiv(Exp e)

At div expression node.

Parameters:

e - Exp

Returns:

Exp

atMod

protected Exp atMod(Exp e)

At mod expression node.

Parameters:

e - Exp

Returns:

Exp

atAnd

protected Exp atAnd(Exp e)

At and expression node.

Parameters:

e - Exp

Returns:

Exp

atOr

protected Exp atOr(Exp e)

At or expression node.

Parameters:

e - Exp

Returns:

Exp

atXor

protected Exp atXor(Exp e)

At xor expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpEq

protected Exp atCmpEq(Exp e)

At EQ expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpNe

protected Exp atCmpNe(Exp e)

At NE expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpGt

protected Exp atCmpGt(Exp e)

At GT expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpGe

protected Exp atCmpGe(Exp e)

At GE expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpLt

protected Exp atCmpLt(Exp e)

At LT expression node.

Parameters:

e - Exp

Returns:

Exp

atCmpLe

protected Exp atCmpLe(Exp e)

At LE expression node.

Parameters:

e - Exp

Returns:

Exp

atLShift

protected Exp atLShift(Exp e)

At L-shift expression node.

Parameters:

e - Exp

Returns:

Exp

atARShift

protected Exp atARShift(Exp e)

At arithmetic R-shift expression node.

Parameters:

e - Exp

Returns:

Exp

atRShift

protected Exp atRShift(Exp e)

At logical R-shift expression node.

Parameters:

e - Exp

Returns:

Exp

atNot

protected Exp atNot(Exp e)

At not expression node.

Parameters:

e - Exp

Returns:

Exp

atNeg

protected Exp atNeg(Exp e)

At negative expression node.

Parameters:

e - Exp

Returns:

Exp

atAddr

protected Exp atAddr(Exp e)

At address expression node.

Parameters:

e - Exp

Returns:

Exp

atConv

protected Exp atConv(Exp e)

At cast expression node.

Parameters:

e - Exp

Returns:

Exp

atDecay

protected Exp atDecay(Exp e)

At decay expression node.

Parameters:

e - Exp

Returns:

Exp

atUndecay

protected Exp atUndecay(Exp e)

At undecay expression node.

Parameters:

e - Exp

Returns:

Exp

atContents

protected Exp atContents(Exp e)

At indirection expression node.

Parameters:

e - Exp

Returns:

Exp

atAssign

protected Exp atAssign(Exp e)

At assign expression node.

Parameters:

e - Exp

Returns:

Exp

atOffset

protected Exp atOffset(Exp e)

At offset(difference of address) expression node.

Parameters:

e - Exp

Returns:

Exp

atLgAnd

protected Exp atLgAnd(Exp e)

At logical-and expression node.

Parameters:

e - Exp

Returns:

Exp

atLgOr

protected Exp atLgOr(Exp e)

At logical-or expression node.

Parameters:

e - Exp

Returns:

Exp

atSelect

protected Exp atSelect(Exp e)

At selection expression node.

Parameters:

e - Exp

Returns:

Exp

atComma

protected Exp atComma(Exp e)

At comma expression node.

Parameters:

e - Exp

Returns:

Exp

atEqZero

protected Exp atEqZero(Exp e)

At logical-not expression node.

Parameters:

e - Exp

Returns:

Exp

atPre

protected Exp atPre(int op,
                    Exp e)

At pre-operator expression node.

Parameters:

e - Exp

Returns:

Exp

atPost

protected Exp atPost(int op,
                     Exp e)

At post-operator expression node.

Parameters:

e - Exp

Returns:

Exp

atAddAssign

protected Exp atAddAssign(Exp e)

At add-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atSubAssign

protected Exp atSubAssign(Exp e)

At sub-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atMulAssign

protected Exp atMulAssign(Exp e)

At mul-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atDivAssign

protected Exp atDivAssign(Exp e)

At div-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atModAssign

protected Exp atModAssign(Exp e)

At mod-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atLShiftAssign

protected Exp atLShiftAssign(Exp e)

At L-shift-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atRShiftAssign

protected Exp atRShiftAssign(Exp e)

At R-shift-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atAndAssign

protected Exp atAndAssign(Exp e)

At and-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atOrAssign

protected Exp atOrAssign(Exp e)

At or-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atXorAssign

protected Exp atXorAssign(Exp e)

At xor-assign expression node.

Parameters:

e - Exp

Returns:

Exp

atExpList

protected Exp atExpList(ExpListExp e)

At expression list node.

Parameters:

e - Exp

Returns:

Exp

atExpRepeat

protected Exp atExpRepeat(Exp e)

At expression repeatation node.

Parameters:

e - Exp

Returns:

Exp

atSubpDefinition

protected SubpDefinition atSubpDefinition(SubpDefinition s)

At block statement node.

Parameters:

s - BlockStmt

atInfStmt

protected InfStmt atInfStmt(InfStmt pInf)

atInfStmt parses the pragma body in the form of String and change its symbols to instances of Sym (Var, Subp, Label, Const) and items enclosed in parenthesis to IrList changing its elements to Sym, etc. This may be called twice for the same pragma. In the second call, return pInf unchanged because it is already in the final form.

Returns:

InfStmt having Sym elements and (nested) IrList.

processPragmaItem

IrList processPragmaItem(ParseString pParseString,
                         java.lang.String pNextItem,
                         IrList pList)