Index: clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -290,9 +290,9 @@
       SmallString<80> buf;
       llvm::raw_svector_ostream OS(buf);
       assert(CurrentFunctionDescription);
-      OS << "Null pointer argument in call to " << CurrentFunctionDescription
-         << ' ' << IdxOfArg << llvm::getOrdinalSuffix(IdxOfArg)
-         << " parameter";
+      OS << "Null pointer passed as " << IdxOfArg
+         << llvm::getOrdinalSuffix(IdxOfArg) << " argument to "
+         << CurrentFunctionDescription;
 
       emitNullArgBug(C, stateNull, S, OS.str());
     }
@@ -1536,7 +1536,10 @@
                                       bool ReturnEnd, bool IsBounded,
                                       ConcatFnKind appendK,
                                       bool returnPtr) const {
-  CurrentFunctionDescription = "string copy function";
+  if (appendK == ConcatFnKind::none)
+    CurrentFunctionDescription = "string copy function";
+  else
+    CurrentFunctionDescription = "string concatenation function";
   ProgramStateRef state = C.getState();
   const LocationContext *LCtx = C.getLocationContext();
 
Index: clang/test/Analysis/bsd-string.c
===================================================================
--- clang/test/Analysis/bsd-string.c
+++ clang/test/Analysis/bsd-string.c
@@ -33,11 +33,11 @@
 }
 
 void f4() {
-  strlcpy(NULL, "abcdef", 6); // expected-warning{{Null pointer argument in call to string copy function}}
+  strlcpy(NULL, "abcdef", 6); // expected-warning{{Null pointer passed as 1st argument to string copy function}}
 }
 
 void f5() {
-  strlcat(NULL, "abcdef", 6); // expected-warning{{Null pointer argument in call to string copy function}}
+  strlcat(NULL, "abcdef", 6); // expected-warning{{Null pointer passed as 1st argument to string concatenation function}}
 }
 
 void f6() {
Index: clang/test/Analysis/bstring.c
===================================================================
--- clang/test/Analysis/bstring.c
+++ clang/test/Analysis/bstring.c
@@ -148,12 +148,12 @@
 
 void memcpy10() {
   char a[4] = {0};
-  memcpy(0, a, 4); // expected-warning{{Null pointer argument in call to memory copy function}}
+  memcpy(0, a, 4); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void memcpy11() {
   char a[4] = {0};
-  memcpy(a, 0, 4); // expected-warning{{Null pointer argument in call to memory copy function}}
+  memcpy(a, 0, 4); // expected-warning{{Null pointer passed as 2nd argument to memory copy function}}
 }
 
 void memcpy12() {
@@ -173,7 +173,7 @@
 
 void memcpy_unknown_size_warn (size_t n) {
   char a[4];
-  void *result = memcpy(a, 0, n); // expected-warning{{Null pointer argument in call to memory copy function}}
+  void *result = memcpy(a, 0, n); // expected-warning{{Null pointer passed as 2nd argument to memory copy function}}
   clang_analyzer_eval(result == a); // no-warning (above is fatal)
 }
 
@@ -268,12 +268,12 @@
 
 void mempcpy10() {
   char a[4] = {0};
-  mempcpy(0, a, 4); // expected-warning{{Null pointer argument in call to memory copy function}}
+  mempcpy(0, a, 4); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void mempcpy11() {
   char a[4] = {0};
-  mempcpy(a, 0, 4); // expected-warning{{Null pointer argument in call to memory copy function}}
+  mempcpy(a, 0, 4); // expected-warning{{Null pointer passed as 2nd argument to memory copy function}}
 }
 
 void mempcpy12() {
@@ -327,7 +327,7 @@
 
 void mempcpy_unknown_size_warn (size_t n) {
   char a[4];
-  void *result = mempcpy(a, 0, n); // expected-warning{{Null pointer argument in call to memory copy function}}
+  void *result = mempcpy(a, 0, n); // expected-warning{{Null pointer passed as 2nd argument to memory copy function}}
   clang_analyzer_eval(result == a); // no-warning (above is fatal)
 }
 
Index: clang/test/Analysis/cstring-ranges.c
===================================================================
--- clang/test/Analysis/cstring-ranges.c
+++ clang/test/Analysis/cstring-ranges.c
@@ -2,6 +2,8 @@
 
 // This test verifies argument source range highlighting.
 // Otherwise we've no idea which of the arguments is null.
+// These days we actually also have it in the message,
+// but the range is still great to have.
 
 char *strcpy(char *, const char *);
 
@@ -10,6 +12,6 @@
   strcpy(a, b);
 }
 
-// CHECK: warning: Null pointer argument in call to string copy function
+// CHECK: warning: Null pointer passed as 1st argument to string copy function
 // CHECK-NEXT: strcpy(a, b);
 // CHECK-NEXT: ^      ~
Index: clang/test/Analysis/null-deref-path-notes.c
===================================================================
--- clang/test/Analysis/null-deref-path-notes.c
+++ clang/test/Analysis/null-deref-path-notes.c
@@ -13,40 +13,40 @@
 
 void f1(char *source) {
   char *destination = 0; // expected-note{{'destination' initialized to a null pointer value}}
-  memcpy(destination + 0, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                       // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination + 0, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                       // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void f2(char *source) {
   char *destination = 0; // expected-note{{'destination' initialized to a null pointer value}}
-  memcpy(destination - 0, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                       // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination - 0, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                       // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void f3(char *source) {
   char *destination = 0; // expected-note{{'destination' initialized to a null pointer value}}
   destination = destination + 0; // expected-note{{Null pointer value stored to 'destination'}}
-  memcpy(destination, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                   // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                   // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void f4(char *source) {
   char *destination = 0; // expected-note{{'destination' initialized to a null pointer value}}
   destination = destination - 0; // expected-note{{Null pointer value stored to 'destination'}}
-  memcpy(destination, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                   // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                   // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void f5(char *source) {
   char *destination1 = 0; // expected-note{{'destination1' initialized to a null pointer value}}
   char *destination2 = destination1 + 0; // expected-note{{'destination2' initialized to a null pointer value}}
-  memcpy(destination2, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                    // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination2, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                    // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
 
 void f6(char *source) {
   char *destination1 = 0; // expected-note{{'destination1' initialized to a null pointer value}}
   char *destination2 = destination1 - 0; // expected-note{{'destination2' initialized to a null pointer value}}
-  memcpy(destination2, source, 10); // expected-warning{{Null pointer argument in call to memory copy function}}
-                                    // expected-note@-1{{Null pointer argument in call to memory copy function}}
+  memcpy(destination2, source, 10); // expected-warning{{Null pointer passed as 1st argument to memory copy function}}
+                                    // expected-note@-1{{Null pointer passed as 1st argument to memory copy function}}
 }
Index: clang/test/Analysis/null-deref-ps-region.c
===================================================================
--- clang/test/Analysis/null-deref-ps-region.c
+++ clang/test/Analysis/null-deref-ps-region.c
@@ -39,7 +39,7 @@
 
 void testConcreteNull() {
   int *x = 0;
-  memset(x, 0, 1); // expected-warning {{Null pointer argument in call to memory set function}}
+  memset(x, 0, 1); // expected-warning {{Null pointer passed as 1st argument to memory set function}}
 }
 
 void testStackArray() {
Index: clang/test/Analysis/string.c
===================================================================
--- clang/test/Analysis/string.c
+++ clang/test/Analysis/string.c
@@ -97,7 +97,7 @@
 }
 
 size_t strlen_null() {
-  return strlen(0); // expected-warning{{Null pointer argument in call to string length function}}
+  return strlen(0); // expected-warning{{Null pointer passed as 1st argument to string length function}}
 }
 
 size_t strlen_fn() {
@@ -251,7 +251,7 @@
 }
 
 size_t strnlen_null() {
-  return strnlen(0, 3); // expected-warning{{Null pointer argument in call to string length function}}
+  return strnlen(0, 3); // expected-warning{{Null pointer passed as 1st argument to string length function}}
 }
 
 size_t strnlen_fn() {
@@ -322,11 +322,11 @@
 
 
 void strcpy_null_dst(char *x) {
-  strcpy(NULL, x); // expected-warning{{Null pointer argument in call to string copy function}}
+  strcpy(NULL, x); // expected-warning{{Null pointer passed as 1st argument to string copy function}}
 }
 
 void strcpy_null_src(char *x) {
-  strcpy(x, NULL); // expected-warning{{Null pointer argument in call to string copy function}}
+  strcpy(x, NULL); // expected-warning{{Null pointer passed as 2nd argument to string copy function}}
 }
 
 void strcpy_fn(char *x) {
@@ -424,15 +424,15 @@
 
 
 void strcat_null_dst(char *x) {
-  strcat(NULL, x); // expected-warning{{Null pointer argument in call to string copy function}}
+  strcat(NULL, x); // expected-warning{{Null pointer passed as 1st argument to string concatenation function}}
 }
 
 void strcat_null_src(char *x) {
-  strcat(x, NULL); // expected-warning{{Null pointer argument in call to string copy function}}
+  strcat(x, NULL); // expected-warning{{Null pointer passed as 2nd argument to string concatenation function}}
 }
 
 void strcat_fn(char *x) {
-  strcat(x, (char*)&strcat_fn); // expected-warning{{Argument to string copy function is the address of the function 'strcat_fn', which is not a null-terminated string}}
+  strcat(x, (char*)&strcat_fn); // expected-warning{{Argument to string concatenation function is the address of the function 'strcat_fn', which is not a null-terminated string}}
 }
 
 void strcat_effects(char *y) {
@@ -523,11 +523,11 @@
 
 
 void strncpy_null_dst(char *x) {
-  strncpy(NULL, x, 5); // expected-warning{{Null pointer argument in call to string copy function}}
+  strncpy(NULL, x, 5); // expected-warning{{Null pointer passed as 1st argument to string copy function}}
 }
 
 void strncpy_null_src(char *x) {
-  strncpy(x, NULL, 5); // expected-warning{{Null pointer argument in call to string copy function}}
+  strncpy(x, NULL, 5); // expected-warning{{Null pointer passed as 2nd argument to string copy function}}
 }
 
 void strncpy_fn(char *x) {
@@ -631,15 +631,15 @@
 
 
 void strncat_null_dst(char *x) {
-  strncat(NULL, x, 4); // expected-warning{{Null pointer argument in call to string copy function}}
+  strncat(NULL, x, 4); // expected-warning{{Null pointer passed as 1st argument to string concatenation function}}
 }
 
 void strncat_null_src(char *x) {
-  strncat(x, NULL, 4); // expected-warning{{Null pointer argument in call to string copy function}}
+  strncat(x, NULL, 4); // expected-warning{{Null pointer passed as 2nd argument to string concatenation function}}
 }
 
 void strncat_fn(char *x) {
-  strncat(x, (char*)&strncat_fn, 4); // expected-warning{{Argument to string copy function is the address of the function 'strncat_fn', which is not a null-terminated string}}
+  strncat(x, (char*)&strncat_fn, 4); // expected-warning{{Argument to string concatenation function is the address of the function 'strncat_fn', which is not a null-terminated string}}
 }
 
 void strncat_effects(char *y) {
@@ -812,13 +812,13 @@
 void strcmp_null_0() {
   char *x = NULL;
   char *y = "123";
-  strcmp(x, y); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strcmp(x, y); // expected-warning{{Null pointer passed as 1st argument to string comparison function}}
 }
 
 void strcmp_null_1() {
   char *x = "123";
   char *y = NULL;
-  strcmp(x, y); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strcmp(x, y); // expected-warning{{Null pointer passed as 2nd argument to string comparison function}}
 }
 
 void strcmp_diff_length_0() {
@@ -921,13 +921,13 @@
 void strncmp_null_0() {
   char *x = NULL;
   char *y = "123";
-  strncmp(x, y, 3); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strncmp(x, y, 3); // expected-warning{{Null pointer passed as 1st argument to string comparison function}}
 }
 
 void strncmp_null_1() {
   char *x = "123";
   char *y = NULL;
-  strncmp(x, y, 3); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strncmp(x, y, 3); // expected-warning{{Null pointer passed as 2nd argument to string comparison function}}
 }
 
 void strncmp_diff_length_0() {
@@ -1030,13 +1030,13 @@
 void strcasecmp_null_0() {
   char *x = NULL;
   char *y = "123";
-  strcasecmp(x, y); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strcasecmp(x, y); // expected-warning{{Null pointer passed as 1st argument to string comparison function}}
 }
 
 void strcasecmp_null_1() {
   char *x = "123";
   char *y = NULL;
-  strcasecmp(x, y); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strcasecmp(x, y); // expected-warning{{Null pointer passed as 2nd argument to string comparison function}}
 }
 
 void strcasecmp_diff_length_0() {
@@ -1121,13 +1121,13 @@
 void strncasecmp_null_0() {
   char *x = NULL;
   char *y = "123";
-  strncasecmp(x, y, 3); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strncasecmp(x, y, 3); // expected-warning{{Null pointer passed as 1st argument to string comparison function}}
 }
 
 void strncasecmp_null_1() {
   char *x = "123";
   char *y = NULL;
-  strncasecmp(x, y, 3); // expected-warning{{Null pointer argument in call to string comparison function}}
+  strncasecmp(x, y, 3); // expected-warning{{Null pointer passed as 2nd argument to string comparison function}}
 }
 
 void strncasecmp_diff_length_0() {
@@ -1183,11 +1183,11 @@
 char *strsep(char **stringp, const char *delim);
 
 void strsep_null_delim(char *s) {
-  strsep(&s, NULL); // expected-warning{{Null pointer argument in call to strsep()}}
+  strsep(&s, NULL); // expected-warning{{Null pointer passed as 2nd argument to strsep()}}
 }
 
 void strsep_null_search() {
-  strsep(NULL, ""); // expected-warning{{Null pointer argument in call to strsep()}}
+  strsep(NULL, ""); // expected-warning{{Null pointer passed as 1st argument to strsep()}}
 }
 
 void strsep_return_original_pointer(char *s) {
@@ -1433,7 +1433,7 @@
 void bzero1_null() {
   char *a = NULL;
 
-  bzero(a, 10); // expected-warning{{Null pointer argument in call to memory clearance function}}
+  bzero(a, 10); // expected-warning{{Null pointer passed as 1st argument to memory clearance function}}
 }
 
 void bzero2_char_array_null() {
@@ -1453,7 +1453,7 @@
 void explicit_bzero1_null() {
   char *a = NULL;
 
-  explicit_bzero(a, 10); // expected-warning{{Null pointer argument in call to memory clearance function}}
+  explicit_bzero(a, 10); // expected-warning{{Null pointer passed as 1st argument to memory clearance function}}
 }
 
 void explicit_bzero2_clear_mypassword() {