[analyzer] CStringSyntaxChecks: Fix an off-by-one error in the strlcat() check.

oth strlcat and strlcpy cut off their safe bound for the argument value
at sizeof(destination). There's no need to subtract 1 in only one
of these cases.

Differential Revision: https://reviews.llvm.org/D57981

rdar://problem/47873212

llvm-svn: 353583

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/test/Analysis/cstring-syntax.c b/clang/test/Analysis/cstring-syntax.c
index d2e12e8303b..f01de36c1af 100644
--- a/clang/test/Analysis/cstring-syntax.c
+++ b/clang/test/Analysis/cstring-syntax.c
@@ -33,6 +33,7 @@ void testStrlcpy(const char *src) {
   strlcpy(dest, src, ulen);
   strlcpy(dest + 5, src, 5);
   strlcpy(dest + 5, src, 10); // expected-warning {{The third argument allows to potentially copy more bytes than it should. Replace with the value sizeof(<destination buffer>) or lower}}
+  strlcpy(dest, "aaaaaaaaaaaaaaa", 10); // no-warning
 }
 
 void testStrlcat(const char *src) {
@@ -51,4 +52,5 @@ void testStrlcat(const char *src) {
   strlcat(dest, src, ulen);
   strlcpy(dest, src, 5);
   strlcat(dest + 5, src, badlen); // expected-warning {{The third argument allows to potentially copy more bytes than it should. Replace with the value sizeof(<destination buffer>) or lower}}
+  strlcat(dest, "aaaaaaaaaaaaaaa", 10); // no-warning
 }