cb042b058
Denys Vlasenko
2021-07-03
Subject
awk: restore strdup elision optimization in assignment
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editors/awk.c+17 -8
| @@ -102,7 +102,7 @@ enum { | |
| #define VF_USER 0x0200 /* 1 = user input (may be numeric string) */ | |
| #define VF_SPECIAL 0x0400 /* 1 = requires extra handling when changed */ | |
| #define VF_WALK 0x0800 /* 1 = variable has alloc'd x.walker list */ | |
| - | #define VF_FSTR 0x1000 /* 1 = var::string points to fstring buffer */ |
| + | #define VF_FSTR 0x1000 /* 1 = don't free() var::string (not malloced, or is owned by something else) */ |
| #define VF_CHILD 0x2000 /* 1 = function arg; x.parent points to source */ | |
| #define VF_DIRTY 0x4000 /* 1 = variable was set explicitly */ | |
| @@ -1371,6 +1371,12 @@ static node *parse_expr(uint32_t term_tc) | |
| cn->a.n = vn->a.n; | |
| if (tc & TS_BINOP) { | |
| cn->l.n = vn; | |
| + | //FIXME: this is the place to detect and reject assignments to non-lvalues. |
| + | //Currently we allow "assignments" to consts and temporaries, nonsense like this: |
| + | // awk 'BEGIN { "qwe" = 1 }' |
| + | // awk 'BEGIN { 7 *= 7 }' |
| + | // awk 'BEGIN { length("qwe") = 1 }' |
| + | // awk 'BEGIN { (1+1) += 3 }' |
| expected_tc = TS_OPERAND | TS_UOPPRE | TC_REGEXP; | |
| if ((t_info & OPCLSMASK) == OC_PGETLINE) { | |
| /* it's a pipe */ | |
| @@ -3043,14 +3049,17 @@ static var *evaluate(node *op, var *res) | |
| case XC( OC_MOVE ): | |
| debug_printf_eval("MOVE\n"); | |
| /* if source is a temporary string, jusk relink it to dest */ | |
| - | //Disabled: if R.v is numeric but happens to have cached R.v->string, |
| - | //then L.v ends up being a string, which is wrong |
| - | // if (R.v == TMPVAR1 && R.v->string) { |
| - | // res = setvar_p(L.v, R.v->string); |
| - | // R.v->string = NULL; |
| - | // } else { |
| + | if (R.v == TMPVAR1 |
| + | && !(R.v->type & VF_NUMBER) |
| + | /* Why check !NUMBER? if R.v is a number but has cached R.v->string, |
| + | * L.v ends up a string, which is wrong */ |
| + | /*&& R.v->string - always not NULL (right?) */ |
| + | ) { |
| + | res = setvar_p(L.v, R.v->string); /* avoids strdup */ |
| + | R.v->string = NULL; |
| + | } else { |
| res = copyvar(L.v, R.v); | |
| - | // } |
| + | } |
| break; | |
| case XC( OC_TERNARY ): | |