Re: [patch #6569] Allow grep to work in small stack environment

[Jim Meyering]

Patrick Boyd wrote:
> Yes. It is part of the EDK or the EDK 2.
>
> http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=EDK
> http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=EDK2
>
> On Wed, Sep 8, 2010 at 11:25 AM, Jim Meyering <address@hidden> wrote:
>
>     Patrick Boyd wrote:
>     > This change allows a UEFI port of grep to work in the UEFI simulator 
> which
>     runs
>     > on top of Windows or Linux with a pretty small stack.
>
>     Thanks.  Regarding "the UEFI simulator", do you have a URL for it?
>     Is it freely available?

Good.  Then I'll reference those in the commit log for your change.
I'll push the following pretty soon:

>From ed6e79b69224dbf08546fda101a49fb65127f964 Mon Sep 17 00:00:00 2001
From: Patrick Boyd <address@hidden>
Date: Fri, 27 Aug 2010 10:31:37 +0200
Subject: [PATCH 1/2] dfa: reduce stack usage

* src/dfa.c (dfaanalyze): Allocate GRPS and LABELS arrays from heap,
not on the stack.  With this change, grep can now run in these UEFI
simulators:
http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=EDK
http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=EDK2
---
 src/dfa.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/dfa.c b/src/dfa.c
index 91124b6..94d4b84 100644
--- a/src/dfa.c
+++ b/src/dfa.c
@@ -2306,8 +2306,8 @@ dfaanalyze (struct dfa *d, int searchflag)
 void
 dfastate (int s, struct dfa *d, int trans[])
 {
-  position_set grps[NOTCHAR];  /* As many as will ever be needed. */
-  charclass labels[NOTCHAR];   /* Labels corresponding to the groups. */
+  position_set *grps;          /* As many as will ever be needed. */
+  charclass *labels;           /* Labels corresponding to the groups. */
   int ngrps = 0;               /* Number of groups actually used. */
   position pos;                        /* Current position being considered. */
   charclass matches;           /* Set of matching characters. */
@@ -2331,6 +2331,9 @@ dfastate (int s, struct dfa *d, int trans[])
 #endif
   int i, j, k;

+  grps = xnmalloc (NOTCHAR, sizeof *grps);
+  labels = xnmalloc (NOTCHAR, sizeof *labels);
+
   /* Initialize the set of letters, if necessary. */
   if (! initialized)
     {
@@ -2593,6 +2596,8 @@ dfastate (int s, struct dfa *d, int trans[])
     free(grps[i].elems);
   free(follows.elems);
   free(tmp.elems);
+  free(grps);
+  free(labels);
 }

 /* Some routines for manipulating a compiled dfa's transition tables.
--
1.7.3.rc0.174.g69763


>From 27cc54e4b59517da9bbe4ca7955bf1ce4b911333 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Wed, 8 Sep 2010 18:34:36 +0200
Subject: [PATCH 2/2] build: update gnulib submodule to latest

---
 gnulib |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/gnulib b/gnulib
index 12e64e4..7b854ba 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 12e64e44eb5b9178a2cbcfd4a8b34b6fc3e021ea
+Subproject commit 7b854ba12ccca6d68981f96c0f21ded6a962372e
--
1.7.3.rc0.174.g69763