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sh: Use iteration instead of recursion to evaluate semicolon lists.

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This reduces CPU and memory usage when executing long lists (such
as long functions).
This commit is contained in:
Jilles Tjoelker 2010-10-31 12:06:02 +00:00
parent 189795fe68
commit dca867f1c9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=214599
2 changed files with 27 additions and 15 deletions
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15
bin/sh/eval.c
View File

@ -196,6 +196,7 @@ void
evaltree(union node *n, int flags)
{
int do_etest;
union node *next;
do_etest = 0;
if (n == NULL) {
@ -203,6 +204,8 @@ evaltree(union node *n, int flags)
exitstatus = 0;
goto out;
}
do {
next = NULL;
#ifndef NO_HISTORY
displayhist = 1; /* show history substitutions done with fc */
#endif
@ -212,20 +215,20 @@ evaltree(union node *n, int flags)
evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
if (evalskip)
goto out;
evaltree(n->nbinary.ch2, flags);
next = n->nbinary.ch2;
break;
case NAND:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus != 0) {
goto out;
}
evaltree(n->nbinary.ch2, flags);
next = n->nbinary.ch2;
break;
case NOR:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus == 0)
goto out;
evaltree(n->nbinary.ch2, flags);
next = n->nbinary.ch2;
break;
case NREDIR:
evalredir(n, flags);
@ -242,9 +245,9 @@ evaltree(union node *n, int flags)
if (evalskip)
goto out;
if (exitstatus == 0)
evaltree(n->nif.ifpart, flags);
next = n->nif.ifpart;
else if (n->nif.elsepart)
evaltree(n->nif.elsepart, flags);
next = n->nif.elsepart;
else
exitstatus = 0;
break;
@ -281,6 +284,8 @@ evaltree(union node *n, int flags)
flushout(&output);
break;
}
n = next;
} while (n != NULL);
out:
if (pendingsigs)
dotrap();

27
bin/sh/parser.c
View File

@ -227,13 +227,13 @@ parsecmd(int interact)
static union node *
list(int nlflag, int erflag)
{
union node *n1, *n2, *n3;
union node *ntop, *n1, *n2, *n3;
int tok;
checkkwd = 2;
if (!nlflag && !erflag && tokendlist[peektoken()])
return NULL;
n1 = NULL;
ntop = n1 = NULL;
for (;;) {
n2 = andor();
tok = readtoken();
@ -250,14 +250,21 @@ list(int nlflag, int erflag)
n2 = n3;
}
}
if (n1 == NULL) {
n1 = n2;
if (ntop == NULL)
ntop = n2;
else if (n1 == NULL) {
n1 = (union node *)stalloc(sizeof (struct nbinary));
n1->type = NSEMI;
n1->nbinary.ch1 = ntop;
n1->nbinary.ch2 = n2;
ntop = n1;
}
else {
n3 = (union node *)stalloc(sizeof (struct nbinary));
n3->type = NSEMI;
n3->nbinary.ch1 = n1;
n3->nbinary.ch1 = n1->nbinary.ch2;
n3->nbinary.ch2 = n2;
n1->nbinary.ch2 = n3;
n1 = n3;
}
switch (tok) {
@ -269,28 +276,28 @@ list(int nlflag, int erflag)
if (tok == TNL) {
parseheredoc();
if (nlflag)
return n1;
return ntop;
} else if (tok == TEOF && nlflag) {
parseheredoc();
return n1;
return ntop;
} else {
tokpushback++;
}
checkkwd = 2;
if (!nlflag && !erflag && tokendlist[peektoken()])
return n1;
return ntop;
break;
case TEOF:
if (heredoclist)
parseheredoc();
else
pungetc(); /* push back EOF on input */
return n1;
return ntop;
default:
if (nlflag || erflag)
synexpect(-1);
tokpushback++;
return n1;
return ntop;
}
}
}