中间生成

下面为中间生成节点：

      pnode = ^tnode;
      { basic class for the intermediated representation fpc uses }
      tnode = class
      private
         fppuidx : longint;        ppu的索引
         function getppuidx:longint;
      public
         { type of this node }
         nodetype : tnodetype;    节点类型
         { type of the current code block, general/const/type }
         blocktype : tblock_type;    块类型
         { expected location of the result of this node (pass1) }
         expectloc : tcgloc;    异常存储位置类型
         { the location of the result of this node (pass2) }
         location : tlocation;    存储位置
         { the parent node of this is node    }
         { this field is set by concattolist  }
         parent : tnode;    父节点
         { next node in control flow on the same block level, i.e.
           for loop nodes, this is the next node after the end of the loop,
           same for if and case, if this field is nil, the next node is the procedure exit,
           for the last node in a loop this is set to the loop header
           this field is set only for control flow nodes }
         successor : tnode;    后继节点
         { there are some properties about the node stored }
         flags  : tnodeflags;    节点属性
         resultdef     : tdef;    返回类型定义
         resultdefderef : tderef;    返回类型解定义
         fileinfo      : tfileposinfo;    文件信息
         localswitches : tlocalswitches;    局部开关
         verbosity     : longint;    打印信息属性
         optinfo : poptinfo;        优化信息
         constructor create(t:tnodetype);
         { this constructor is only for creating copies of class }
         { the fields are copied by getcopy                      }
         constructor createforcopy;
         constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);virtual;
         destructor destroy;override;
         procedure ppuwrite(ppufile:tcompilerppufile);virtual;
         procedure buildderefimpl;virtual;
         procedure derefimpl;virtual;
         procedure resolveppuidx;virtual;

         { toggles the flag }
         procedure toggleflag(f : tnodeflag);

         { the 1.1 code generator may override pass_1 }
         { and it need not to implement det_* then    }
         { 1.1: pass_1 returns a value<>0 if the node has been transformed }
         { 2.0: runs pass_typecheck and det_temp                           }
         function pass_1 : tnode;virtual;abstract;
         { dermines the resultdef of the node }
         function pass_typecheck : tnode;virtual;abstract;

         { tries to simplify the node, returns a value <>nil if a simplified
           node has been created }
         function simplify(forinline : boolean) : tnode;virtual;
{$ifdef state_tracking}
         { Does optimizations by keeping track of the variable states
           in a procedure }
         function track_state_pass(exec_known:boolean):boolean;virtual;
{$endif}
         { For a t1:=t2 tree, mark the part of the tree t1 that gets
           written to (normally the loadnode) as write access. }
         procedure mark_write;virtual;
         { dermines the number of necessary temp. locations to evaluate
           the node }
         procedure det_temp;virtual;abstract;

         procedure pass_generate_code;virtual;abstract;

         { comparing of nodes }
         function isequal(p : tnode) : boolean;
         { to implement comparisation, override this method }
         function docompare(p : tnode) : boolean;virtual;
         { wrapper for getcopy }
         function getcopy : tnode;

         { does the real copying of a node }
         function dogetcopy : tnode;virtual;

         { returns the real loadn/temprefn a node refers to,
           skipping (absolute) equal type conversions        }
         function actualtargetnode: tnode;virtual;

         procedure insertintolist(l : tnodelist);virtual;
         { writes a node for debugging purpose, shouldn't be called }
         { direct, because there is no test for nil, use printnode  }
         { to write a complete tree }
         procedure printnodeinfo(var t:text);virtual;
         procedure printnodedata(var t:text);virtual;
         procedure printnodetree(var t:text);virtual;
         procedure concattolist(l : tlinkedlist);virtual;
         function ischild(p : tnode) : boolean;virtual;

         { ensures that the optimizer info record is allocated }
         function allocoptinfo : poptinfo;inline;
         property ppuidx:longint read getppuidx;
      end;

      tnodeclass = class of tnode;

      tnodeclassarray = array[tnodetype] of tnodeclass;

    单叉
      { this node is the anchestor for all nodes with at least   }
      { one child, you have to use it if you want to use         }
      { true- and current_procinfo.CurrFalseLabel                                     }
      punarynode = ^tunarynode;
      tunarynode = class(tnode)
         left : tnode;            左节点
         constructor create(t:tnodetype;l : tnode);
         constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
         destructor destroy;override;
         procedure ppuwrite(ppufile:tcompilerppufile);override;
         procedure buildderefimpl;override;
         procedure derefimpl;override;
         procedure concattolist(l : tlinkedlist);override;
         function ischild(p : tnode) : boolean;override;
         function docompare(p : tnode) : boolean;override;
         function dogetcopy : tnode;override;
         procedure insertintolist(l : tnodelist);override;
         procedure printnodedata(var t:text);override;
      end;

    二叉树
      pbinarynode = ^tbinarynode;
      tbinarynode = class(tunarynode)
         right : tnode;            右节点
         constructor create(t:tnodetype;l,r : tnode);    
         constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
         destructor destroy;override;
         procedure ppuwrite(ppufile:tcompilerppufile);override;
         procedure buildderefimpl;override;
         procedure derefimpl;override;
         procedure concattolist(l : tlinkedlist);override;
         function ischild(p : tnode) : boolean;override;
         function docompare(p : tnode) : boolean;override;
         procedure swapleftright;
         function dogetcopy : tnode;override;
         procedure insertintolist(l : tnodelist);override;
         procedure printnodedata(var t:text);override;
         procedure printnodelist(var t:text);
      end;

    三叉树    
      ptertiarynode = ^ttertiarynode;
      ttertiarynode = class(tbinarynode)
         third : tnode;            第三节点
         constructor create(_t:tnodetype;l,r,t : tnode);
         constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
         destructor destroy;override;
         procedure ppuwrite(ppufile:tcompilerppufile);override;
         procedure buildderefimpl;override;
         procedure derefimpl;override;
         procedure concattolist(l : tlinkedlist);override;
         function ischild(p : tnode) : boolean;override;
         function docompare(p : tnode) : boolean;override;
         function dogetcopy : tnode;override;
         procedure insertintolist(l : tnodelist);override;
         procedure printnodedata(var t:text);override;
      end;


    操作节点
      tbinopnode = class(tbinarynode)
         constructor create(t:tnodetype;l,r : tnode);virtual;
         function docompare(p : tnode) : boolean;override;
      end;   



    注册所有类型中间生成节点
   procedure registernodes;
      {
        Register all possible nodes in the nodeclass array that
        will be used for loading the nodes from a ppu
      }
      begin
        nodeclass[addn]:=caddnode;
        nodeclass[muln]:=caddnode;
        nodeclass[subn]:=caddnode;
        nodeclass[divn]:=cmoddivnode;
        nodeclass[symdifn]:=caddnode;
        nodeclass[modn]:=cmoddivnode;
        nodeclass[assignn]:=cassignmentnode;
        nodeclass[loadn]:=cloadnode;
        nodeclass[rangen]:=crangenode;
        nodeclass[ltn]:=caddnode;
        nodeclass[lten]:=caddnode;
        nodeclass[gtn]:=caddnode;
        nodeclass[gten]:=caddnode;
        nodeclass[equaln]:=caddnode;
        nodeclass[unequaln]:=caddnode;
        nodeclass[inn]:=cinnode;
        nodeclass[orn]:=caddnode;
        nodeclass[xorn]:=caddnode;
        nodeclass[shrn]:=cshlshrnode;
        nodeclass[shln]:=cshlshrnode;
        nodeclass[slashn]:=caddnode;
        nodeclass[andn]:=caddnode;
        nodeclass[subscriptn]:=csubscriptnode;
        nodeclass[derefn]:=cderefnode;
        nodeclass[addrn]:=caddrnode;
        nodeclass[ordconstn]:=cordconstnode;
        nodeclass[typeconvn]:=ctypeconvnode;
        nodeclass[calln]:=ccallnode;
        nodeclass[callparan]:=ccallparanode;
        nodeclass[realconstn]:=crealconstnode;
        nodeclass[unaryminusn]:=cunaryminusnode;
        nodeclass[unaryplusn]:=cunaryplusnode;
        nodeclass[asmn]:=casmnode;
        nodeclass[vecn]:=cvecnode;
        nodeclass[pointerconstn]:=cpointerconstnode;
        nodeclass[stringconstn]:=cstringconstnode;
        nodeclass[notn]:=cnotnode;
        nodeclass[inlinen]:=cinlinenode;
        nodeclass[niln]:=cnilnode;
        nodeclass[errorn]:=cerrornode;
        nodeclass[typen]:=ctypenode;
        nodeclass[setelementn]:=csetelementnode;
        nodeclass[setconstn]:=csetconstnode;
        nodeclass[blockn]:=cblocknode;
        nodeclass[statementn]:=cstatementnode;
        nodeclass[ifn]:=cifnode;
        nodeclass[breakn]:=cbreaknode;
        nodeclass[continuen]:=ccontinuenode;
        nodeclass[whilerepeatn]:=cwhilerepeatnode;
        nodeclass[forn]:=cfornode;
        nodeclass[exitn]:=cexitnode;
        nodeclass[withn]:=cwithnode;
        nodeclass[casen]:=ccasenode;
        nodeclass[labeln]:=clabelnode;
        nodeclass[goton]:=cgotonode;
        nodeclass[tryexceptn]:=ctryexceptnode;
        nodeclass[raisen]:=craisenode;
        nodeclass[tryfinallyn]:=ctryfinallynode;
        nodeclass[onn]:=connode;
        nodeclass[isn]:=cisnode;
        nodeclass[asn]:=casnode;
        nodeclass[starstarn]:=caddnode;
        nodeclass[arrayconstructorn]:=carrayconstructornode;
        nodeclass[arrayconstructorrangen]:=carrayconstructorrangenode;
        nodeclass[tempcreaten]:=ctempcreatenode;
        nodeclass[temprefn]:=ctemprefnode;
        nodeclass[tempdeleten]:=ctempdeletenode;
        nodeclass[addoptn]:=caddnode;
        nodeclass[nothingn]:=cnothingnode;
        nodeclass[loadvmtaddrn]:=cloadvmtaddrnode;
        nodeclass[guidconstn]:=cguidconstnode;
        nodeclass[rttin]:=crttinode;
        nodeclass[loadparentfpn]:=cloadparentfpnode;
      end;