[compiler-rt] r196572 - [msan] Allow strlen() (and similar functions) of shadow memory.

[Evgeniy Stepanov]

Author: eugenis
Date: Fri Dec  6 03:19:07 2013
New Revision: 196572

URL: http://llvm.org/viewvc/llvm-project?rev=196572&view=rev
Log:
[msan] Allow strlen() (and similar functions) of shadow memory.

Added:
    compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc   (with props)
Modified:
    compiler-rt/trunk/lib/msan/msan.cc

Added: compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc?rev=196572&view=auto
==============================================================================
--- compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc (added)
+++ compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc Fri Dec  6 03:19:07 2013
@@ -0,0 +1,24 @@
+// RUN: %clangxx_msan -m64 -O0 %s -o %t && %t
+
+// Check that strlen() and similar intercepted functions can be called on shadow
+// memory.
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+const char *mem_to_shadow(const char *p) {
+  return (char *)((uintptr_t)p & ~0x400000000000ULL);
+}
+
+int main(void) {
+  const char *s = "abcdef";
+  assert(strlen(s) == 6);
+  assert(strlen(mem_to_shadow(s)) == 0);
+
+  char *t = new char[42];
+  t[41] = 0;
+  assert(strlen(mem_to_shadow(t)) == 41);
+  return 0;
+}

Propchange: compiler-rt/trunk/lib/msan/lit_tests/strlen_of_shadow.cc
------------------------------------------------------------------------------
    svn:eol-style = LF

Modified: compiler-rt/trunk/lib/msan/msan.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan.cc?rev=196572&r1=196571&r2=196572&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan.cc (original)
+++ compiler-rt/trunk/lib/msan/msan.cc Fri Dec  6 03:19:07 2013
@@ -398,7 +398,8 @@ void __msan_print_param_shadow() {
 }
 
 sptr __msan_test_shadow(const void *x, uptr size) {
-  unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x);
+  if (!MEM_IS_APP(x)) return -1;
+  unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x);
   for (uptr i = 0; i < size; ++i)
     if (s[i])
       return i;