From ac631cbe7021105c7fb8438deaeef66fe544b9aa Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <aldyh@redhat.com>
Date: Fri, 29 Jul 2016 16:40:55 +0000
Subject: [PATCH] libiberty.h (MAX_ALLOCA_SIZE): New macro.
include/
* libiberty.h (MAX_ALLOCA_SIZE): New macro.
libiberty/
* make-relative-prefix.c (make_relative_prefix_1): Fall back to
malloc if alloca argument is greater than MAX_ALLOCA_SIZE.
From-SVN: r238880
---
include/ChangeLog | 4 ++++
include/libiberty.h | 11 +++++++++++
libiberty/ChangeLog | 5 +++++
libiberty/make-relative-prefix.c | 11 ++++++++---
4 files changed, 28 insertions(+), 3 deletions(-)
diff --git a/include/ChangeLog b/include/ChangeLog
index 8b46056ce312..06be0281e26c 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,7 @@
+2016-07-29 Aldy Hernandez <aldyh@redhat.com>
+
+ * libiberty.h (MAX_ALLOCA_SIZE): New macro.
+
2016-05-26 Chung-Lin Tang <cltang@codesourcery.com>
* gomp-constants.h (GOMP_VERSION): Increment to 1, add comment to
diff --git a/include/libiberty.h b/include/libiberty.h
index a9c885fc6704..605ff56abd8f 100644
--- a/include/libiberty.h
+++ b/include/libiberty.h
@@ -397,6 +397,17 @@ extern void hex_init (void);
/* Save files used for communication between processes. */
#define PEX_SAVE_TEMPS 0x4
+/* Max number of alloca bytes per call before we must switch to malloc.
+
+ ?? Swiped from gnulib's regex_internal.h header. Is this actually
+ the case? This number seems arbitrary, though sane.
+
+ The OS usually guarantees only one guard page at the bottom of the stack,
+ and a page size can be as small as 4096 bytes. So we cannot safely
+ allocate anything larger than 4096 bytes. Also care for the possibility
+ of a few compiler-allocated temporary stack slots. */
+#define MAX_ALLOCA_SIZE 4032
+
/* Prepare to execute one or more programs, with standard output of
each program fed to standard input of the next.
FLAGS As above.
diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index 6209195ab38b..a2e49a12cea8 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,8 @@
+2016-07-29 Aldy Hernandez <aldyh@redhat.com>
+
+ * make-relative-prefix.c (make_relative_prefix_1): Fall back to
+ malloc if alloca argument is greater than MAX_ALLOCA_SIZE.
+
2016-07-15 Jason Merrill <jason@redhat.com>
* cp-demangle.c (cplus_demangle_operators): Add f[lrLR].
diff --git a/libiberty/make-relative-prefix.c b/libiberty/make-relative-prefix.c
index fe639d18bd28..fa813998be3e 100644
--- a/libiberty/make-relative-prefix.c
+++ b/libiberty/make-relative-prefix.c
@@ -233,6 +233,7 @@ make_relative_prefix_1 (const char *progname, const char *bin_prefix,
int i, n, common;
int needed_len;
char *ret = NULL, *ptr, *full_progname;
+ char *alloc_ptr = NULL;
if (progname == NULL || bin_prefix == NULL || prefix == NULL)
return NULL;
@@ -256,7 +257,10 @@ make_relative_prefix_1 (const char *progname, const char *bin_prefix,
#ifdef HAVE_HOST_EXECUTABLE_SUFFIX
len += strlen (HOST_EXECUTABLE_SUFFIX);
#endif
- nstore = (char *) alloca (len);
+ if (len < MAX_ALLOCA_SIZE)
+ nstore = (char *) alloca (len);
+ else
+ alloc_ptr = nstore = (char *) malloc (len);
startp = endp = temp;
while (1)
@@ -312,12 +316,12 @@ make_relative_prefix_1 (const char *progname, const char *bin_prefix,
else
full_progname = strdup (progname);
if (full_progname == NULL)
- return NULL;
+ goto bailout;
prog_dirs = split_directories (full_progname, &prog_num);
free (full_progname);
if (prog_dirs == NULL)
- return NULL;
+ goto bailout;
bin_dirs = split_directories (bin_prefix, &bin_num);
if (bin_dirs == NULL)
@@ -395,6 +399,7 @@ make_relative_prefix_1 (const char *progname, const char *bin_prefix,
free_split_directories (prog_dirs);
free_split_directories (bin_dirs);
free_split_directories (prefix_dirs);
+ free (alloc_ptr);
return ret;
}
--
GitLab