[cfe-dev] clang printf correspondence between conversion specifier and arguments

Cristian Draghici cristian.draghici at gmail.com
Thu Jan 21 04:17:10 CST 2010


Hi

I am attaching a patch for "%i" and "%d".

I've not carried on with the rest of the conversion specifiers because they
should probably be handled by a single block of code (vs having one common
block per type of argument - i.e. one for int, unsigned int, etc).

i.e.

builtinTypeKind conversionSpecifierType;
case 'i':
case 'd':
    conversionSpecifierType = BuiltinType::Int;
case 'o':
case 'u':
case 'X':
case 'x':
   conversionSpecifierType = BuiltinType::UInt;
[..]
case 'p':
     /* do diagnostics here based on the conversionSpecifierType and the
current argument */


Thanks,
Cristi
PS Is there a way to get the string representation of the built-in type?
(i.e. 'int' out of 'BuiltinType::Int')




On Thu, Jan 21, 2010 at 8:24 AM, Ted Kremenek <kremenek at apple.com> wrote:

> Hi Cristi,
>
> This is definitely on the right track.
>
> To add a warning, you only need to modify the TableGen files (.td), as the
> .inc files are generated from the .td files during the build.  Specifically,
> you only need to modify DiagnosticSemaKinds.td and add one warning to the
> Format group.  Your warning declaration would look something like:
>
>  def my_warning : Warning<
>  "conversion specifies type '%0' but the argument has type '%1'">,
> InGroup<Format>;
>
> You would then use it similarly to the
> warn_printf_asterisk_precision_wrong_type warning (in SemaChecking.cpp),
> except you specify two QualType arguments instead of one.
>
> Please also include a couple test cases that show when the warning is both
> reported and *not* reported.  The test cases should also include the use of
> typedefs (which I believe your logic already handles).
>
> - Ted
>
> On Jan 19, 2010, at 11:26 PM, Cristian Draghici wrote:
>
> > Hi
> >
> > I've started looking at printf correspondence between conversion
> specifier and arguments.
> >
> > 1/ Am I on the right track with the patch below?
> >
> > 2/ Assuming an affirmative answer on (1), I'm not sure how to define a
> new warning (I used warn_printf_asterisk_width_wrong_type which is wrong in
> this case).
> > I'm guessing defs are in include/clang/Basic/DiagnosticSemaKinds.inc and
> .td and referred in DiagnosticGroups.inc and .td
> > A new diagnostic would be needed, along the lines of "conversion
> specifies type 'X', but argument has type 'Y'"
> >
> >
> > Thanks for your time,
> > Cristi
> >
> >
> > cristi:clang diciu$ svn diff  ./lib/Sema/SemaChecking.cpp
> > Index: lib/Sema/SemaChecking.cpp
> > ===================================================================
> > --- lib/Sema/SemaChecking.cpp (revision 93981)
> > +++ lib/Sema/SemaChecking.cpp (working copy)
> > @@ -1147,7 +1147,17 @@
> >      //
> >      // FIXME: additional checks will go into the following cases.
> >      case 'i':
> > -    case 'd':
> > +    case 'd': {
> > +      if(numDataArgs >= format_idx+numConversions+1) {
> > +        const Expr *E2 = TheCall->getArg(format_idx+numConversions+1);
> > +        const BuiltinType *BT = E2->getType()->getAs<BuiltinType>();
> > +        if(BT == NULL || BT->getKind() != BuiltinType::Int) {
> > +          SourceLocation Loc = getLocationOfStringLiteralByte(FExpr,
> StrIdx);
> > +          Diag(Loc, diag::warn_printf_asterisk_width_wrong_type)
> > +            << E2->getType() << E2->getSourceRange();
> > +        }
> > +      }
> > +    }
> >      case 'o':
> >      case 'u':
> >      case 'x':
> >
> >
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
>
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Index: test/Sema/format-strings.c
===================================================================
--- test/Sema/format-strings.c	(revision 94069)
+++ test/Sema/format-strings.c	(working copy)
@@ -103,6 +103,16 @@
   printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
 }
 
+void check_conversion_specifier_vs_argument(int x) {
+  printf("%i", x); // no warning
+  printf("%i", "foo"); // expected-warning {{conversion specifies type 'int' but the argument has type 'char *'}}
+  printf("%i %i", x, "foo"); // expected-warning {{conversion specifies type 'int' but the argument has type 'char *'}}
+
+  typedef int myint;
+  myint i1=12;
+  printf("%i", i1); // no warning
+}
+
 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
 
 void test_myprintf() {
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td	(revision 94069)
+++ include/clang/Basic/DiagnosticSemaKinds.td	(working copy)
@@ -2435,6 +2435,9 @@
 def warn_printf_asterisk_precision_wrong_type : Warning<
   "field precision should have type 'int', but argument has type %0">,
   InGroup<Format>;
+def warn_printf_conversion_argument_type_mismatch : Warning<
+  "conversion specifies type '%0' but the argument has type %1">,
+  InGroup<Format>;
 
 // CHECK: returning address/reference of stack memory
 def warn_ret_stack_addr : Warning<
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp	(revision 94069)
+++ lib/Sema/SemaChecking.cpp	(working copy)
@@ -1155,7 +1155,17 @@
     //
     // FIXME: additional checks will go into the following cases.
     case 'i':
-    case 'd':
+    case 'd': {
+      if(!HasVAListArg && numDataArgs + format_idx > numConversions) {
+        const Expr *E2 = TheCall->getArg(numConversions+format_idx+1);
+        const BuiltinType *BT = E2->getType()->getAs<BuiltinType>();
+        if(BT == NULL || BT->getKind() != BuiltinType::Int) {
+          SourceLocation Loc = getLocationOfStringLiteralByte(FExpr, StrIdx);
+          Diag(Loc, diag::warn_printf_conversion_argument_type_mismatch)
+            << "int" << E2->getType() << E2->getSourceRange();
+        }
+      }
+    }
     case 'o':
     case 'u':
     case 'x':


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