[cfe-commits] r132996 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaChecking.cpp test/SemaCXX/warn-memset-bad-sizeof.cpp
Nico Weber
nicolasweber at gmx.de
Tue Jun 14 09:14:58 PDT 2011
Author: nico
Date: Tue Jun 14 11:14:58 2011
New Revision: 132996
URL: http://llvm.org/viewvc/llvm-project?rev=132996&view=rev
Log:
Warn on memset(ptr, 0, sizeof(ptr)). Diagnostic wording by Jordy Rose.
Added:
cfe/trunk/test/SemaCXX/warn-memset-bad-sizeof.cpp
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaChecking.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=132996&r1=132995&r2=132996&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Jun 14 11:14:58 2011
@@ -269,6 +269,9 @@
InGroup<DiagGroup<"dynamic-class-memaccess">>;
def note_bad_memaccess_silence : Note<
"explicitly cast the pointer to silence this warning">;
+def warn_sizeof_pointer : Warning<
+ "the argument to sizeof is pointer type %0, expected %1 to match "
+ "%select{first|second}2 argument to %3">;
/// main()
// static/inline main() are not errors in C, just in C++.
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=132996&r1=132995&r2=132996&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Tue Jun 14 11:14:58 2011
@@ -1812,6 +1812,20 @@
return false;
}
+/// \brief If E is a sizeof expression, returns the expression's type in
+/// OutType.
+static bool sizeofExprType(const Expr* E, QualType *OutType) {
+ if (const UnaryExprOrTypeTraitExpr *SizeOf =
+ dyn_cast<UnaryExprOrTypeTraitExpr>(E)) {
+ if (SizeOf->getKind() != clang::UETT_SizeOf)
+ return false;
+
+ *OutType = SizeOf->getTypeOfArgument();
+ return true;
+ }
+ return false;
+}
+
/// \brief Check for dangerous or invalid arguments to memset().
///
/// This issues warnings on known problematic, dangerous or unspecified
@@ -1827,8 +1841,10 @@
return;
unsigned LastArg = FnName->isStr("memset")? 1 : 2;
+ const Expr *LenExpr = Call->getArg(2)->IgnoreParenImpCasts();
for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
+ SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
QualType DestTy = Dest->getType();
if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
@@ -1836,6 +1852,17 @@
if (PointeeTy->isVoidType())
continue;
+ // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p).
+ QualType SizeofTy;
+ if (sizeofExprType(LenExpr, &SizeofTy) &&
+ Context.typesAreCompatible(SizeofTy, DestTy)) {
+ // Note: This complains about sizeof(typeof(p)) as well.
+ SourceLocation loc = LenExpr->getSourceRange().getBegin();
+ Diag(loc, diag::warn_sizeof_pointer)
+ << SizeofTy << PointeeTy << ArgIdx << FnName;
+ break;
+ }
+
// Always complain about dynamic classes.
if (isDynamicClassType(PointeeTy)) {
DiagRuntimeBehavior(
@@ -1847,7 +1874,6 @@
continue;
}
- SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::note_bad_memaccess_silence)
Added: cfe/trunk/test/SemaCXX/warn-memset-bad-sizeof.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-memset-bad-sizeof.cpp?rev=132996&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-memset-bad-sizeof.cpp (added)
+++ cfe/trunk/test/SemaCXX/warn-memset-bad-sizeof.cpp Tue Jun 14 11:14:58 2011
@@ -0,0 +1,97 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+//
+extern "C" void *memset(void *, int, unsigned);
+extern "C" void *memmove(void *s1, const void *s2, unsigned n);
+extern "C" void *memcpy(void *s1, const void *s2, unsigned n);
+
+struct S {int a, b, c, d;};
+typedef S* PS;
+
+struct Foo {};
+typedef const Foo& CFooRef;
+typedef const Foo CFoo;
+typedef volatile Foo VFoo;
+typedef const volatile Foo CVFoo;
+
+typedef double Mat[4][4];
+
+template <class Dest, class Source>
+inline Dest bit_cast(const Source& source) {
+ Dest dest;
+ memcpy(&dest, &source, sizeof(dest));
+ return dest;
+}
+
+// http://www.lysator.liu.se/c/c-faq/c-2.html#2-6
+void f(char fake_array[8], Mat m, const Foo& const_foo) {
+ S s;
+ S* ps = &s;
+ PS ps2 = &s;
+ char arr[5];
+ char* parr[5];
+ Foo foo;
+
+ /* Should warn */
+ memset(&s, 0, sizeof(&s)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memset'}}
+ memset(ps, 0, sizeof(ps)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memset'}}
+ memset(ps2, 0, sizeof(ps2)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'PS' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+ memset(ps2, 0, sizeof(typeof(ps2))); // \
+ // expected-warning {{the argument to sizeof is pointer type 'typeof (ps2)' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+ memset(ps2, 0, sizeof(PS)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'PS' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+ memset(fake_array, 0, sizeof(fake_array)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'char *', expected 'char' to match first argument to 'memset'}}
+
+ memcpy(&s, 0, sizeof(&s)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memcpy'}}
+ memcpy(0, &s, sizeof(&s)); // \
+ // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match second argument to 'memcpy'}}
+
+ /* Shouldn't warn */
+ memset((void*)&s, 0, sizeof(&s));
+ memset(&s, 0, sizeof(s));
+ memset(&s, 0, sizeof(S));
+ memset(&s, 0, sizeof(const S));
+ memset(&s, 0, sizeof(volatile S));
+ memset(&s, 0, sizeof(volatile const S));
+ memset(&foo, 0, sizeof(CFoo));
+ memset(&foo, 0, sizeof(VFoo));
+ memset(&foo, 0, sizeof(CVFoo));
+ memset(ps, 0, sizeof(*ps));
+ memset(ps2, 0, sizeof(*ps2));
+ memset(ps2, 0, sizeof(typeof(*ps2)));
+ memset(arr, 0, sizeof(arr));
+ memset(parr, 0, sizeof(parr));
+
+ memcpy(&foo, &const_foo, sizeof(Foo));
+ memcpy((void*)&s, 0, sizeof(&s));
+ memcpy(0, (void*)&s, sizeof(&s));
+
+ CFooRef cfoo = foo;
+ memcpy(&foo, &cfoo, sizeof(Foo));
+
+ memcpy(0, &arr, sizeof(arr));
+ typedef char Buff[8];
+ memcpy(0, &arr, sizeof(Buff));
+
+ unsigned char* puc;
+ bit_cast<char*>(puc);
+
+ float* pf;
+ bit_cast<int*>(pf);
+
+ int iarr[14];
+ memset(&iarr[0], 0, sizeof iarr);
+
+ int* iparr[14];
+ memset(&iparr[0], 0, sizeof iparr);
+
+ memset(m, 0, sizeof(Mat));
+
+ // Copy to raw buffer shouldn't warn either
+ memcpy(&foo, &arr, sizeof(Foo));
+ memcpy(&arr, &foo, sizeof(Foo));
+}
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