From b605851ac60827687b1f48fbd3971703de555654 Mon Sep 17 00:00:00 2001
From: Frank Busse <bb0xfb@gmail.com>
Date: Tue, 1 Dec 2020 10:42:53 +0000
Subject: klee-libc: simplify mempcpy

---
 runtime/klee-libc/mempcpy.c      | 11 ++++------
 test/Runtime/klee-libc/mempcpy.c | 44 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 test/Runtime/klee-libc/mempcpy.c

diff --git a/runtime/klee-libc/mempcpy.c b/runtime/klee-libc/mempcpy.c
index 31712251..c1cc175c 100644
--- a/runtime/klee-libc/mempcpy.c
+++ b/runtime/klee-libc/mempcpy.c
@@ -7,13 +7,10 @@
 //
 //===----------------------------------------------------------------------===*/
 
-#include <stdlib.h>
+#undef _GNU_SOURCE
 
-void *mempcpy(void *destaddr, void const *srcaddr, size_t len) {
-  char *dest = destaddr;
-  char const *src = srcaddr;
+#include <string.h>
 
-  while (len-- > 0)
-    *dest++ = *src++;
-  return dest;
+void *mempcpy(void *destaddr, void const *srcaddr, size_t len) {
+  return (char *)memcpy(destaddr, srcaddr, len) + len;
 }
diff --git a/test/Runtime/klee-libc/mempcpy.c b/test/Runtime/klee-libc/mempcpy.c
new file mode 100644
index 00000000..7ba3bb70
--- /dev/null
+++ b/test/Runtime/klee-libc/mempcpy.c
@@ -0,0 +1,44 @@
+// validate mempcpy implementation
+// RUN: %clang %s -emit-llvm %O0opt -c -o %t.bc
+// RUN: rm -rf %t.klee-out
+// RUN: %klee --output-dir=%t.klee-out --libc=klee --exit-on-error %t.bc
+
+#include "klee/klee.h"
+
+// do not #define _GNU_SOURCE - just declare mempcpy for all systems
+
+#include <assert.h>
+#include <string.h>
+
+void *mempcpy(void *destaddr, void const *srcaddr, size_t len);
+
+int main() {
+  // char arrays
+  char s1[] = "foofoo";
+  char s2[] = "barbar";
+  char *spos = (char *)mempcpy(s2, s1, 3);
+
+  assert(spos == &s2[3]);
+  assert(!strcmp(s2, "foobar"));
+  assert(!strcmp(s1, "foofoo"));
+
+  // int arrays
+  int arr1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  int arr2[] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
+  int *pos = (int *)mempcpy(arr2, arr1, sizeof(int) * 5);
+
+  assert(pos == &arr2[5]);
+  for (int i = 0; i < 10; ++i) assert(arr1[i] == i);
+  for (int i = 0; i <  5; ++i) assert(arr2[i] == i);
+  for (int i = 5; i < 10; ++i) assert(arr2[i] == -1);
+
+  // symbolic int arrays
+  int sarr1[10];
+  int sarr2[10];
+  klee_make_symbolic(sarr1, sizeof(int) * 10, "sarr1");
+  klee_make_symbolic(sarr2, sizeof(int) * 10, "sarr2");
+  pos = (int *)mempcpy(sarr2, sarr1, sizeof(int) * 5);
+
+  assert(pos == &sarr2[5]);
+  assert(!memcmp(sarr2, sarr1, sizeof(int) * 5));
+}
-- 
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