ado@elsie.UUCP (Arthur David Olson) (06/29/89)
> Last week I spent an entire day tracking down one of those bugs you just > don't see after staring at your code too long. It was of the form: > if (condition); > action; For those with source, here are the changes to the 4.3BSD versions of "cgram.y" and "lint.c" that catch both bodyless if's and bodyless else's. One other challenge is dealt with here--code such as #include <math.h> double; function(x) { return fabs(x - 1); } which misbehaves because of the incorrect semicolon. -- The RCMP is to spaceflight as the Canadian government is to freedom. Arthur David Olson ado@alw.nih.gov ADO is a trademark of Ampex. *** 3.1/cgram.y Thu Jun 29 10:41:33 1989 --- 3.2/cgram.y Thu Jun 29 10:41:34 1989 *************** *** 52,57 **** --- 57,67 ---- %{ static int fake = 0; + #ifndef ASWAS + #ifdef LINT + extern char * gripenull; + #endif /* LINT */ + #endif /* !ASWAS */ #ifndef FLEXNAMES static char fakename[NCHNAM+1]; #else *************** *** 70,76 **** ; data_def: oattributes SM ! ={ $1->in.op = FREE; } | oattributes init_dcl_list SM ={ $1->in.op = FREE; } | oattributes fdeclarator { --- 80,99 ---- ; data_def: oattributes SM ! ={ ! #ifndef ASWAS ! extern int asm_esc; ! ! if ($1->in.type != STRTY && ! $1->in.type != UNIONTY && ! $1->in.type != ENUMTY && ! (!asm_esc || curclass != SNULL || ! $1->in.type != INT || ! $1->fn.cdim != 0 || ! $1->fn.csiz != INT)) ! werror("null effect"); ! #endif /* !ASWAS */ ! $1->in.op = FREE; } | oattributes init_dcl_list SM ={ $1->in.op = FREE; } | oattributes fdeclarator { *************** *** 401,406 **** --- 424,434 ---- if( psavbc > &asavbc[BCSZ-2] ) cerror( "nesting too deep" ); *psavbc++ = regvar; *psavbc++ = autooff; + #ifndef ASWAS + #ifdef LINT + gripenull = 0; + #endif /* LINT */ + #endif /* !ASWAS */ } ; *************** *** 409,414 **** --- 437,447 ---- | compoundstmt | ifprefix statement ={ deflab($1); + #ifndef ASWAS + #ifdef LINT + gripenull = 0; + #endif /* LINT */ + #endif /* !ASWAS */ reached = 1; } | ifelprefix statement *************** *** 416,421 **** --- 449,459 ---- deflab( $1 ); reached = 1; } + #ifndef ASWAS + #ifdef LINT + gripenull = 0; + #endif /* LINT */ + #endif /* !ASWAS */ } | whprefix statement ={ branch( contlab ); *************** *** 497,502 **** --- 535,548 ---- goto rch; } | SM + /* #ifndef ASWAS */ + ={ + #ifdef LINT + if (hflag && gripenull != 0) + werror(gripenull); + #endif + } + /* #endif !ASWAS */ | error SM | error RC | label statement *************** *** 530,535 **** --- 576,586 ---- ifprefix: IF LP e RP ={ ecomp( buildtree( CBRANCH, $3, bcon( $$=getlab()) ) ) ; reached = 1; + #ifndef ASWAS + #ifdef LINT + gripenull = "bodyless if"; + #endif /* !LINT */ + #endif /* !ASWAS */ } ; ifelprefix: ifprefix statement ELSE *************** *** 537,542 **** --- 588,598 ---- else $$ = NOLAB; deflab( $1 ); reached = 1; + #ifndef ASWAS + #ifdef LINT + gripenull = "bodyless else"; + #endif /* LINT */ + #endif /* !ASWAS */ } ; *** 3.1/lint.c Thu Jun 29 10:54:59 1989 --- 3.1.1.1/lint.c Thu Jun 29 10:55:00 1989 *************** *** 95,100 **** --- 95,103 ---- } } + #ifndef ASWAS + char * gripenull; + #endif /* !defined ASWAS */ ecode( p ) NODE *p; { /* compile code for p */ *************** *** 101,106 **** --- 104,112 ---- fwalk( p, contx, EFF ); lnp = lnames; lprt( p, EFF, 0 ); + #ifndef ASWAS + gripenull = 0; + #endif /* !defined ASWAS */ } ejobcode( flag ){