[cfe-commits] r161052 - in /cfe/trunk: lib/Analysis/FormatString.cpp lib/Analysis/ScanfFormatString.cpp test/Sema/format-strings-scanf.c test/Sema/format-strings.c

[Hans Wennborg]

Author: hans
Date: Tue Jul 31 11:37:47 2012
New Revision: 161052

URL: http://llvm.org/viewvc/llvm-project?rev=161052&view=rev
Log:
-Wformat: better handling of qualifiers on pointer arguments

Warn about using pointers to const-qualified types as arguments to
scanf. Ignore the volatile qualifier when checking if types match.

Modified:
    cfe/trunk/lib/Analysis/FormatString.cpp
    cfe/trunk/lib/Analysis/ScanfFormatString.cpp
    cfe/trunk/test/Sema/format-strings-scanf.c
    cfe/trunk/test/Sema/format-strings.c

Modified: cfe/trunk/lib/Analysis/FormatString.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/FormatString.cpp?rev=161052&r1=161051&r2=161052&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/FormatString.cpp (original)
+++ cfe/trunk/lib/Analysis/FormatString.cpp Tue Jul 31 11:37:47 2012
@@ -262,6 +262,13 @@
         argTy = ETy->getDecl()->getIntegerType();
       argTy = C.getCanonicalType(argTy).getUnqualifiedType();
 
+      if (const PointerType *PTy = argTy->getAs<PointerType>()) {
+        // Strip volatile qualifier from pointee type.
+        QualType Pointee = PTy->getPointeeType();
+        Pointee.removeLocalVolatile();
+        argTy = C.getPointerType(Pointee);
+      }
+
       if (T == argTy)
         return true;
       // Check for "compatible types".

Modified: cfe/trunk/lib/Analysis/ScanfFormatString.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/ScanfFormatString.cpp?rev=161052&r1=161051&r2=161052&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/ScanfFormatString.cpp (original)
+++ cfe/trunk/lib/Analysis/ScanfFormatString.cpp Tue Jul 31 11:37:47 2012
@@ -453,6 +453,15 @@
 }
 
 bool ScanfArgTypeResult::matchesType(ASTContext& C, QualType argTy) const {
+  // It has to be a pointer type.
+  const PointerType *PT = argTy->getAs<PointerType>();
+  if (!PT)
+    return false;
+
+  // We cannot write through a const qualified pointer.
+  if (PT->getPointeeType().isConstQualified())
+    return false;
+
   switch (K) {
     case InvalidTy:
       llvm_unreachable("ArgTypeResult must be valid");
@@ -463,9 +472,6 @@
     case WCStrTy:
       return ArgTypeResult(ArgTypeResult::WCStrTy).matchesType(C, argTy);
     case PtrToArgTypeResultTy: {
-      const PointerType *PT = argTy->getAs<PointerType>();
-      if (!PT)
-        return false;
       return A.matchesType(C, PT->getPointeeType());
     }
   }

Modified: cfe/trunk/test/Sema/format-strings-scanf.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/format-strings-scanf.c?rev=161052&r1=161051&r2=161052&view=diff
==============================================================================
--- cfe/trunk/test/Sema/format-strings-scanf.c (original)
+++ cfe/trunk/test/Sema/format-strings-scanf.c Tue Jul 31 11:37:47 2012
@@ -126,3 +126,21 @@
   scanf("%n", (void*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'void *'}}
   scanf("%n %c", x, x); // expected-warning{{format specifies type 'char *' but the argument has type 'int *'}}
 }
+
+void test_qualifiers(const int *cip, volatile int* vip,
+                     const char *ccp, volatile char* vcp,
+                     const volatile int *cvip) {
+  scanf("%d", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
+  scanf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
+  scanf("%s", ccp); // expected-warning{{format specifies type 'char *' but the argument has type 'const char *'}}
+  scanf("%d", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
+
+  scanf("%d", vip); // No warning.
+  scanf("%n", vip); // No warning.
+  scanf("%c", vcp); // No warning.
+
+  typedef int* ip_t;
+  typedef const int* cip_t;
+  scanf("%d", (ip_t)0); // No warning.
+  scanf("%d", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
+}

Modified: cfe/trunk/test/Sema/format-strings.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/format-strings.c?rev=161052&r1=161051&r2=161052&view=diff
==============================================================================
--- cfe/trunk/test/Sema/format-strings.c (original)
+++ cfe/trunk/test/Sema/format-strings.c Tue Jul 31 11:37:47 2012
@@ -555,3 +555,19 @@
   test14_foo("%", "%d", p); // expected-warning{{incomplete format specifier}}
   test14_bar("%", "%d", p); // expected-warning{{incomplete format specifier}}
 }
+
+void test_qualifiers(volatile int *vip, const int *cip,
+                     const volatile int *cvip) {
+  printf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
+  printf("%n", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
+
+  printf("%n", vip); // No warning.
+  printf("%p", cip); // No warning.
+  printf("%p", cvip); // No warning.
+
+
+  typedef int* ip_t;
+  typedef const int* cip_t;
+  printf("%n", (ip_t)0); // No warning.
+  printf("%n", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
+}