[PATCH 1/2] Fix nonnull errors reported by UBSAN with GCC 7.

["Martin Liška" <mliska@suse.cz>]

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Hello.

Following patch fixes issues that can be seen with -fsanitize=undefined on GCC 7.

Patch was tested with make test.

Thanks,
Martin

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From e6d2d5ee5614acdbe67b79aeb0fdc9b53cf3a828 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Wed, 5 Apr 2017 14:31:32 +0200
Subject: [PATCH 1/2] Fix nonnull errors reported by UBSAN with GCC 7.

Memory functions like memmove and memcpy should not be called
with an argument equal to NULL.

Signed-off-by: Martin Liska <mliska@suse.cz>
---
 apply.c            | 7 ++++---
 builtin/ls-files.c | 5 +++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/apply.c b/apply.c
index e6dbab26a..78a83f66b 100644
--- a/apply.c
+++ b/apply.c
@@ -2802,9 +2802,10 @@ static void update_image(struct apply_state *state,
 			img->line + applied_pos + preimage_limit,
 			(img->nr - (applied_pos + preimage_limit)) *
 			sizeof(*img->line));
-	memcpy(img->line + applied_pos,
-	       postimage->line,
-	       postimage->nr * sizeof(*img->line));
+	if (postimage->nr)
+		memcpy(img->line + applied_pos,
+			postimage->line,
+			postimage->nr * sizeof(*img->line));
 	if (!state->allow_overlap)
 		for (i = 0; i < postimage->nr; i++)
 			img->line[applied_pos + i].flag |= LINE_PATCHED;
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index d449e46db..01d24314d 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -391,8 +391,9 @@ static void prune_cache(const char *prefix, size_t prefixlen)
 		}
 		last = next;
 	}
-	memmove(active_cache, active_cache + pos,
-		(last - pos) * sizeof(struct cache_entry *));
+	if (last - pos > 0)
+		memmove(active_cache, active_cache + pos,
+			(last - pos) * sizeof(struct cache_entry *));
 	active_nr = last - pos;
 }
 
-- 
2.12.2