[clang] 4a47da2 - [Sema] turns -Wfree-nonheap-object on by default

Christopher Di Bella via cfe-commits cfe-commits at lists.llvm.org
Fri Apr 30 09:08:23 PDT 2021


Sorry, not yet. I'll talk with my TL to see if I can get some time allotted
for this in the next few weeks.

On Thu, 29 Apr 2021 at 16:13, David Blaikie <dblaikie at gmail.com> wrote:

> Ping on this - have you had a chance to look at this false positive?
>
> On Sat, Apr 3, 2021 at 4:29 PM David Blaikie <dblaikie at gmail.com> wrote:
> >
> > Looks like this has a false positive (that's firing on some mlir code,
> > committed a workaround in  499571ea835daf786626a0db1e12f890b6cd8f8d )
> > like this:
> >
> > $ cat test.cpp
> > #include <stdlib.h>
> > void f1(int & x) { free(&x); }
> > int main() { f1(*(int*)malloc(sizeof(int))); }
> >
> > Could you fix that? (& then revert the workaround)
> >
> > On Fri, Jan 15, 2021 at 1:44 PM Christopher Di Bella via cfe-commits
> > <cfe-commits at lists.llvm.org> wrote:
> > >
> > >
> > > Author: Christopher Di Bella
> > > Date: 2021-01-15T21:38:47Z
> > > New Revision: 4a47da2cf440c2f2006d9b04acfef4292de1e263
> > >
> > > URL:
> https://github.com/llvm/llvm-project/commit/4a47da2cf440c2f2006d9b04acfef4292de1e263
> > > DIFF:
> https://github.com/llvm/llvm-project/commit/4a47da2cf440c2f2006d9b04acfef4292de1e263.diff
> > >
> > > LOG: [Sema] turns -Wfree-nonheap-object on by default
> > >
> > > We'd discussed adding the warning to -Wall in D89988. This patch
> honours that.
> > >
> > > Added:
> > >
> > >
> > > Modified:
> > >     clang/include/clang/Basic/DiagnosticGroups.td
> > >     clang/include/clang/Basic/DiagnosticSemaKinds.td
> > >     clang/test/Analysis/NewDelete-intersections.mm
> > >     clang/test/Analysis/free.c
> > >
> > > Removed:
> > >
> > >
> > >
> > >
> ################################################################################
> > > diff  --git a/clang/include/clang/Basic/DiagnosticGroups.td
> b/clang/include/clang/Basic/DiagnosticGroups.td
> > > index d500ab321058..04ba89aa457e 100644
> > > --- a/clang/include/clang/Basic/DiagnosticGroups.td
> > > +++ b/clang/include/clang/Basic/DiagnosticGroups.td
> > > @@ -110,6 +110,7 @@ def FloatConversion :
> > >                                   FloatZeroConversion]>;
> > >
> > >  def FrameAddress : DiagGroup<"frame-address">;
> > > +def FreeNonHeapObject : DiagGroup<"free-nonheap-object">;
> > >  def DoublePromotion : DiagGroup<"double-promotion">;
> > >  def EnumTooLarge : DiagGroup<"enum-too-large">;
> > >  def UnsupportedNan : DiagGroup<"unsupported-nan">;
> > >
> > > diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
> b/clang/include/clang/Basic/DiagnosticSemaKinds.td
> > > index 7d36397a7993..e93657898f58 100644
> > > --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
> > > +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
> > > @@ -7609,7 +7609,7 @@ def err_no_typeid_with_fno_rtti : Error<
> > >  def err_no_dynamic_cast_with_fno_rtti : Error<
> > >    "use of dynamic_cast requires -frtti">;
> > >  def warn_no_dynamic_cast_with_rtti_disabled: Warning<
> > > -  "dynamic_cast will not work since RTTI data is disabled by "
> > > +  "dynamic_cast will not work since RTTI data is disabled by "
> > >    "%select{-fno-rtti-data|/GR-}0">, InGroup<RTTI>;
> > >  def warn_no_typeid_with_rtti_disabled: Warning<
> > >    "typeid will not work since RTTI data is disabled by "
> > > @@ -7625,8 +7625,7 @@ def warn_condition_is_assignment :
> Warning<"using the result of an "
> > >    InGroup<Parentheses>;
> > >  def warn_free_nonheap_object
> > >    : Warning<"attempt to call %0 on non-heap object %1">,
> > > -    InGroup<DiagGroup<"free-nonheap-object">>,
> > > -    DefaultIgnore; // FIXME: add to -Wall after sufficient testing
> > > +    InGroup<FreeNonHeapObject>;
> > >
> > >  // Completely identical except off by default.
> > >  def warn_condition_is_idiomatic_assignment : Warning<"using the
> result "
> > >
> > > diff  --git a/clang/test/Analysis/NewDelete-intersections.mm
> b/clang/test/Analysis/NewDelete-intersections.mm
> > > index f01d62f8d365..6f81034ee349 100644
> > > --- a/clang/test/Analysis/NewDelete-intersections.mm
> > > +++ b/clang/test/Analysis/NewDelete-intersections.mm
> > > @@ -24,9 +24,6 @@
> > >  extern "C" void free(void *);
> > >
> > >  void testMallocFreeNoWarn() {
> > > -  int i;
> > > -  free(&i); // no warn
> > > -
> > >    int *p1 = (int *)malloc(sizeof(int));
> > >    free(++p1); // no warn
> > >
> > > @@ -51,7 +48,7 @@ void testDeleteMalloced() {
> > >
> > >    int *p2 = (int *)__builtin_alloca(sizeof(int));
> > >    delete p2; // no warn
> > > -}
> > > +}
> > >
> > >  void testUseZeroAllocatedMalloced() {
> > >    int *p1 = (int *)malloc(0);
> > > @@ -79,13 +76,13 @@ void testObjcFreeNewed() {
> > >  }
> > >
> > >  void testFreeAfterDelete() {
> > > -  int *p = new int;
> > > +  int *p = new int;
> > >    delete p;
> > >    free(p); // newdelete-warning{{Use of memory after it is freed}}
> > >  }
> > >
> > >  void testStandardPlacementNewAfterDelete() {
> > > -  int *p = new int;
> > > +  int *p = new int;
> > >    delete p;
> > >    p = new (p) int; // newdelete-warning{{Use of memory after it is
> freed}}
> > >  }
> > >
> > > diff  --git a/clang/test/Analysis/free.c b/clang/test/Analysis/free.c
> > > index 0d29bacf274c..b50145713924 100644
> > > --- a/clang/test/Analysis/free.c
> > > +++ b/clang/test/Analysis/free.c
> > > @@ -12,17 +12,23 @@ void *alloca(size_t);
> > >
> > >  void t1 () {
> > >    int a[] = { 1 };
> > > -  free(a); // expected-warning {{Argument to free() is the address of
> the local variable 'a', which is not memory allocated by malloc()}}
> > > +  free(a);
> > > +  // expected-warning at -1{{Argument to free() is the address of the
> local variable 'a', which is not memory allocated by malloc()}}
> > > +  // expected-warning at -2{{attempt to call free on non-heap object
> 'a'}}
> > >  }
> > >
> > >  void t2 () {
> > >    int a = 1;
> > > -  free(&a); // expected-warning {{Argument to free() is the address
> of the local variable 'a', which is not memory allocated by malloc()}}
> > > +  free(&a);
> > > +  // expected-warning at -1{{Argument to free() is the address of the
> local variable 'a', which is not memory allocated by malloc()}}
> > > +  // expected-warning at -2{{attempt to call free on non-heap object
> 'a'}}
> > >  }
> > >
> > >  void t3 () {
> > >    static int a[] = { 1 };
> > > -  free(a); // expected-warning {{Argument to free() is the address of
> the static variable 'a', which is not memory allocated by malloc()}}
> > > +  free(a);
> > > +  // expected-warning at -1{{Argument to free() is the address of the
> static variable 'a', which is not memory allocated by malloc()}}
> > > +  // expected-warning at -2{{attempt to call free on non-heap object
> 'a'}}
> > >  }
> > >
> > >  void t4 (char *x) {
> > > @@ -71,12 +77,16 @@ void t13 () {
> > >  }
> > >
> > >  void t14 (char a) {
> > > -  free(&a); // expected-warning {{Argument to free() is the address
> of the parameter 'a', which is not memory allocated by malloc()}}
> > > +  free(&a);
> > > +  // expected-warning at -1{{Argument to free() is the address of the
> parameter 'a', which is not memory allocated by malloc()}}
> > > +  // expected-warning at -2{{attempt to call free on non-heap object
> 'a'}}
> > >  }
> > >
> > >  static int someGlobal[2];
> > >  void t15 () {
> > > -  free(someGlobal); // expected-warning {{Argument to free() is the
> address of the global variable 'someGlobal', which is not memory allocated
> by malloc()}}
> > > +  free(someGlobal);
> > > +  // expected-warning at -1{{Argument to free() is the address of the
> global variable 'someGlobal', which is not memory allocated by malloc()}}
> > > +  // expected-warning at -2{{attempt to call free on non-heap object
> 'someGlobal'}}
> > >  }
> > >
> > >  void t16 (char **x, int offset) {
> > >
> > >
> > >
> > > _______________________________________________
> > > cfe-commits mailing list
> > > cfe-commits at lists.llvm.org
> > > https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>


-- 
Kind regards,

Christopher Di Bella (he/him/his)
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