Modified format-string checking to not emit a warning when all of the

following hold:

(1) A vprintf-like function is called that takes the argument list via a
    via_list argument.

(2) The format string is a non-literal that is the parameter value of
    the enclosing function, e.g:
    
    void logmessage(const char *fmt,...) { 
      va_list ap;
      va_start(ap,fmt);
      fprintf(fmt,ap);  // Do not emit a warning.
    }
    
In the future this special case will be enhanced to consult the "format"
attribute attached to a function declaration instead of just allowing a blank
check for all function parameters to be used as format strings to vprintf-like
functions. This will happen when more support for attributes becomes
available.

llvm-svn: 45114

1 files changed, 8 insertions, 5 deletions

diff --git a/clang/test/Sema/format-strings.c b/clang/test/Sema/format-strings.c
index e5bbd70bfde..c1e690a3b80 100644
--- a/clang/test/Sema/format-strings.c
+++ b/clang/test/Sema/format-strings.c
@@ -3,6 +3,8 @@
 #include <stdio.h>
 #include <stdarg.h>
 
+char * global_fmt;
+
 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
 
   char * b;
@@ -10,15 +12,16 @@ void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
   va_start(ap,buf);
 
   printf(s); // expected-warning {{format string is not a string literal}}
-  vprintf(s,ap); // expected-warning {{format string is not a string liter}}
+  vprintf(s,ap); // // no-warning
   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
-  vfprintf(fp,s,ap); // expected-warning {{format string is not a string lit}}
+  vfprintf(fp,s,ap); // no-warning
   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
-  vasprintf(&b,s,ap); // expected-warning {{format string is not a string lit}}
+  vasprintf(&b,s,ap); // no-warning
   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
-  vsprintf(buf,s,ap); // expected-warning {{format string is not a string lit}}
-  vsnprintf(buf,2,s,ap); // expected-warning {{mat string is not a string lit}}
+  vsprintf(buf,s,ap); // no-warning
+  vsnprintf(buf,2,s,ap); // no-warning
+  vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
 }
 
 void check_writeback_specifier()