[clang] 4a47da2 - [Sema] turns -Wfree-nonheap-object on by default
David Blaikie via cfe-commits
cfe-commits at lists.llvm.org
Thu Apr 29 16:13:41 PDT 2021
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) {
> >
> >
> >
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