编译原理语义分析实验报告 免费_精品.docx

编译原理综合训练语义分析实验报告指导老师：班级：学生：zeadom学号：学生：学号：2011/6/29语言文法的形式化描述（BNF范式）程序开始P-program i;SDn SC;定义语句SDn-SDSDn|nullSD-var int iSDTSDT - null|,iSDT复合语句SC-begin Sn endSn-S;Sn||null单个语句S-SD|SA|SIF|SW|SC赋值语句SA-i:=E算术表达式E-cET|iET|(E)ETET-AE|CE|DE|null;C-+|-|*|/;布尔表达式B-EAEBT|NOT B|(B)BT BT-DB|nullA-||=|=|=|D-AND|ORif语句SIF-if B then S SELSESELSE-null|else S2while语句SW-while B do S语义规则（属性文法）产生式语义规则i:=E{ Gen(:=, E.PLACE , —，entry(i)) }EE1+E2{ E.PLACE = Newtemp; Gen(+ , E1.PLACE, E2.PLACE , E.PLACE ) }EE1*E2{ E.PLACE = Newtemp; Gen(* , E1.PLACE, E2.PLACE , E.PLACE ) }E－E1{ E.PLACE = Newtemp; Gen(@ , E1.PLACE, — , E.PLACE ) }E (E1){ E.PLACE = E1.PLACE }Ei{ E.PLACE = Entry(i) }产生式语义规则Ei{ E.truelist:=makelist(nextquad); E.falselist:=makelist(nextquad+1); Gen( jnz，entry(i)，— ，0 )； Gen( j ，— ，— ，0 ) }Ei1 R i2{ E.truelist:=makelist(nextquad); E.falselist:=makelist(nextquad+1); Gen( jR，entry(i1)，entry(i2)，0 )； Gen( j ，— ，— ，0 ) }E ┐E1{ E.truelist:= E1.falselist ; E.falselist:= E1.truelist ; }E ( E1 ){ E.truelist:= E1.truelist ; E.falselist:= E1.falselist ; }M ε{ M.quad := nextquad ; }EE1∧ME2{ backpatch(E1.truelist, M.quad ); E.truelist:=E2.truelist; E.falselist:=merge(E1.falselist,E2. Falselist)}EE1∨ME2{ backpatch(E1. falselist, M.quad ); E.truelist:= merge(E1. truelist, E2. truelist); E.falselist:= E2. Falselist }EE1∧ME2{backpatch(E1.truelist, M.quad );E.truelist:= E2.truelist;E.falselist:=merge(E1.falselist, E2.Falselist) }产生式语义规则Sif E then M S1{ backpatch(E.truelist, M.quad );S.nextlist:=merge(E.falselist, S1.nextlist) }M ε{ M.quad := nextquad ; }N ε{ N.nextlist:=makelist(nextquad);Gen( j , — , — , 0 ) }Sif E then M1 S1 N else M2 S2{ backpatch(E.truelist, M1.quad );backpatch(E.falselist, M2.quad );S.nextlist:=merge(S1.nextlist, N.nextlist, S2.nextlist) }Swhile M1 E do M2 S1{ backpatch(S1.nextlist, M1.quad );Gen( j , — , — , M1.quad );backpatch(E.truelist, M2.quad ); S.nextlist:= E.falselist }S begin L end { S.n