From: benjamin priour <vultk...@gcc.gnu.org>
Hi,
(s/we/the analyzer/)
I've been continuing my patch of supporting operator new variants
in the analyzer, and have added a few more test cases.
> > If "y" is null then the allocation failed and dereferencing "y" will
> > cause
> > a segfault, not a "use-of-uninitialized-value".
> > Thus we should stick to 'dereference of NULL 'y'" only.
> > If "y" is non-null then the allocation succeeded and "*y" is
> > initialized
> > since we are calling a default initialization with the empty
> > parenthesis.
>
> I *think* it's possible to have the region_model have y pointing to a
> heap_allocated_region of sizeof(int) size that's been initialized, but
> still have the malloc state machine part of the program_state say that
> the pointer is maybe-null.
By maybe-null are you implying a new sm-malloc state ?
I am not sure to follow on that front.
>
> > This led me to consider having "null-dereference" supersedes
> > "use-of-uninitialized-value", but
> > new PR 110830 made me reexamine it.
> >
> > I believe fixing PR 110830 is thus required before submitting this
> > patch,
> > or we would have some extra irrelevant warnings.
>
> How bad would the problem be? PR 110830 looks a little involved, so is
> there a way to get the current patch in without dragging that extra
> complexity in?
Having "null-dereference" supersedes "use-of-uninitialized-value" would
cause false negative upon conditional return statement (similarly as
demonstrated
in PR 110830).
Since PR 110830 is off for the moment, I have tried solving this
differently.
I have considered using known NULL constraints on heap_allocated_region
as "initialized_value".
You can see below in the diff of region_model::get_store_value
two versions of this approach. The version commented out proved to solve
the issue of the spurious "use-of-unitialized-value" tagging along calls to
"new(std::nothrow) ()". However, this version also shortcircuits the
diagnostics of the "null-dereference" warning.
Given
/* { dg-additional-options "-O0 -fno-exceptions
-fno-analyzer-suppress-followups" } */
#include <new>
struct A
{
int x;
int y;
};
void test_nonthrowing ()
{
A* y = new(std::nothrow) A();
int z = y->x + 2; /* { dg-warning "dereference of NULL 'y'" } */
/* { dg-bogus "use of uninitialized value '\\*y'" "" { xfail *-*-* } .-1
} */
delete y;
}
The analyzer sees gimple
<bb 2> :
_7 = operator new (8, ¬hrow);
if (_7 != 0B)
goto <bb 3>; [INV]
else
goto <bb 4>; [INV]
<bb 3> :
MEM[(struct A *)_7].x = 0;
MEM[(struct A *)_7].y = 0;
iftmp.0_11 = _7;
goto <bb 5>; [INV]
<bb 4> :
iftmp.0_8 = _7;
<bb 5> :
# iftmp.0_2 = PHI <iftmp.0_11(3), iftmp.0_8(4)>
y_12 = iftmp.0_2;
_1 = y_12->x;
z_13 = _1 + 2;
y.1_14 = y_12;
if (y.1_14 != 0B)
goto <bb 6>; [INV]
else
goto <bb 7>; [INV]
<bb 6> :
*y.1_14 ={v} {CLOBBER};
operator delete (y.1_14, 8);
The injurious path, causing the "use-of-uninit" warning is as follows:
<bb 2> :
_7 = operator new (8, ¬hrow);
if (_7 != 0B)
...
else <- Takes false branch
goto <bb 4>; [INV]
...
<bb 4> :
iftmp.0_8 = _7; <- MEM[(struct A*) _7] is left uninit in this bb
<bb 5> :
# iftmp.0_2 = PHI <iftmp.0_11(3), iftmp.0_8(4)> <- iftmp.0_2 = iftmp.0_8(4)
y_12 = iftmp.0_2;
_1 = y_12->x; // deref of null y_12, use of uninit y_12->x
z_13 = _1 + 2; // check_for_poison sets _1 to unknown_svalue
y.1_14 = y_12;
if (y.1_14 != 0B)
goto <bb 6>; [INV]
else
goto <bb 7>; [INV]
Then using the "commented-out" fix, iftmp.0_8 which had an uninit value is
forcibly set to constant_svalue(0), since the analyzer detects a NULL constraint
on &heap_allocated_region.
Unfortunately, this loses all clusters binding on _7 and the followings
variables, such as when we arrive at "_1 = y_12->x", we emit a
"null_deref" not because the heap_allocated_region is in a null state,
but because we are dereferencing a constant "0".
Thus the analysis path no longer tracks down the creation of this
region, and the genese event is "iftmp.0_8 = _7".
As you guess, this loss of information fails a lot of regression tests,
although it achieves the goal of removing the "use-of-uninit" warning.
The second attempt (see get_store_value diff below, the non-commented
out block), actually does nothing, which as I understood through
debugging was to be expected. We are doing the same "constraints" check
as the former version, but only as a last resort before resorting to
creating an initial or unknown svalue.
And instead of creating a constant_svalue(0) as before, now a NULL
constraint only prevents the creation of a poisoned_svalue(uninit)
by setting "check_poisoned" to false.
However in
+ if (reg->get_kind () == RK_FIELD || reg->get_kind () == RK_ELEMENT)
+ {
+ const region *base_reg = reg->get_base_region ();
+ const svalue *base_sval
+ = m_store.get_any_binding (m_mgr->get_store_manager (), base_reg);
+ if (base_sval)
+ {
+ ...
+ }
base_sval is always NULL (which makes sense since otherwise we wouldn't
need to create an initial_svalue).
The spirit behind this second attempt is to not lose any sort of
information, therefore to not forcibly create constant_svalues.
Thus, instead of assigning a null_svalue at "iftmp.0_8 = _7",
rather wait for the latest "_1 = y_12->x;" and prevent the creation
of a "poisoned_svalue (uninit)".
The failings of the second attempt is to find the NULL constraint of
the heap_allocated_region (which still exists thanks to path splitting)
given the COMPONENT_REF y_12->x;
I am unsure as to how to do that, thus this RFC.
Thanks,
Benjamin.
Patch below.
---
Fixed spurious possibly-NULL warning always tagging along throwing
operator new despite it never returning NULL.
Now, operator new is correctly recognized as possibly returning
NULL if and only if it is non-throwing or exceptions have been disabled.
Different standard signatures of operator new are now properly recognized.
Added support of placement new, so that is now properly recognized,
and a 'heap_allocated' region is no longer created for it.
Placement new size is also checked and a 'Wanalyzer-allocation-size'
is emitted when relevant, as well as always a 'Wanalyzer-out-of-bounds'.
'operator new' nothrow variants are detected by checking the types
of the parameters.
Indeed, in a call to new (std::nothrow) (), although the chosen overload
has signature 'operator new (void*, std::nothrow_t&)', where parameter 1
is a reference. In a placement new, parameter 1 will always be a [void]
pointer.
Prior to this patch, some buffers allocated with 'new',
then deleted and thereafter used would result in a
Wanalyzer-use-after-free warning. However,
the wording was "use after 'free' of" instead of the expected
"use after 'delete' of".
This patch fixed this by introducing a new kind of
poisoned value.
Signed-off-by: benjamin priour <vultk...@gcc.gnu.org>
gcc/analyzer/ChangeLog:
* analyzer.h (is_placement_new_p): New declaration.
* call-details.cc
(call_details::maybe_get_arg_region): New function.
Returns the region of the argument at given index if possible.
* call-details.h: Declaration of the above function.
* kf-lang-cp.cc (is_placement_new_p): Returns true if the
gcall is recognized as a placement new.
(kf_operator_delete::impl_call_post): Unbinding a region and its
descendent now poisons with POISON_KIND_DELETED.
(register_known_functions_lang_cp): Known function "operator delete"
is now registered only once independently of its number of parameters.
* region-model.cc (region_model::get_rvalue_1):
(region_model::get_store_value): Attempt to use a region
NULL constraint to emit a null_ptr_svalue instead of an uninit
poisoned_svalue.
(region_model::eval_condition):
Now recursively calls itself if any of the operand is wrapped in a cast.
* sm-malloc.cc (malloc_state_machine::on_stmt):
Add placement new recognition.
* svalue.cc (poison_kind_to_str): Wording for the new PK.
* svalue.h (enum poison_kind): Add value POISON_KIND_DELETED.
gcc/testsuite/ChangeLog:
* g++.dg/analyzer/out-of-bounds-placement-new.C: Added a directive.
* g++.dg/analyzer/placement-new.C: Added tests.
* g++.dg/analyzer/new-2.C: New test.
* g++.dg/analyzer/noexcept-new.C: New test.
* g++.dg/analyzer/placement-new-size.C: New test.
---
gcc/analyzer/analyzer.h | 1 +
gcc/analyzer/call-details.cc | 11 ++
gcc/analyzer/call-details.h | 1 +
gcc/analyzer/kf-lang-cp.cc | 111 +++++++++++++++---
gcc/analyzer/region-model.cc | 68 ++++++++++-
gcc/analyzer/sm-malloc.cc | 17 ++-
gcc/analyzer/svalue.cc | 2 +
gcc/analyzer/svalue.h | 3 +
gcc/testsuite/g++.dg/analyzer/new-2.C | 70 +++++++++++
gcc/testsuite/g++.dg/analyzer/noexcept-new.C | 48 ++++++++
.../analyzer/out-of-bounds-placement-new.C | 2 +-
.../g++.dg/analyzer/placement-new-size.C | 27 +++++
gcc/testsuite/g++.dg/analyzer/placement-new.C | 92 ++++++++++++++-
13 files changed, 427 insertions(+), 26 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/analyzer/new-2.C
create mode 100644 gcc/testsuite/g++.dg/analyzer/noexcept-new.C
create mode 100644 gcc/testsuite/g++.dg/analyzer/placement-new-size.C
diff --git a/gcc/analyzer/analyzer.h b/gcc/analyzer/analyzer.h
index 93a28b4b5cf..f44e8296f5e 100644
--- a/gcc/analyzer/analyzer.h
+++ b/gcc/analyzer/analyzer.h
@@ -401,6 +401,7 @@ extern bool is_std_named_call_p (const_tree fndecl, const
char *funcname,
const gcall *call, unsigned int num_args);
extern bool is_setjmp_call_p (const gcall *call);
extern bool is_longjmp_call_p (const gcall *call);
+extern bool is_placement_new_p (const gcall *call);
extern const char *get_user_facing_name (const gcall *call);
diff --git a/gcc/analyzer/call-details.cc b/gcc/analyzer/call-details.cc
index fa86f55177a..0ac44f3726c 100644
--- a/gcc/analyzer/call-details.cc
+++ b/gcc/analyzer/call-details.cc
@@ -283,6 +283,17 @@ call_details::get_arg_svalue (unsigned idx) const
return m_model->get_rvalue (arg, m_ctxt);
}
+/* If argument IDX's svalue at the callsite is a region_svalue,
+ return the region it points to.
+ Otherwise return NULL. */
+
+const region *
+call_details::maybe_get_arg_region (unsigned idx) const
+{
+ const svalue *sval = get_arg_svalue (idx);
+ return sval->maybe_get_region ();
+}
+
/* Attempt to get the string literal for argument IDX, or return NULL
otherwise.
For use when implementing "__analyzer_*" functions that take
diff --git a/gcc/analyzer/call-details.h b/gcc/analyzer/call-details.h
index 0622cab7856..919338f88b9 100644
--- a/gcc/analyzer/call-details.h
+++ b/gcc/analyzer/call-details.h
@@ -60,6 +60,7 @@ public:
tree get_arg_tree (unsigned idx) const;
tree get_arg_type (unsigned idx) const;
const svalue *get_arg_svalue (unsigned idx) const;
+ const region *maybe_get_arg_region (unsigned idx) const;
const char *get_arg_string_literal (unsigned idx) const;
tree get_fndecl_for_call () const;
diff --git a/gcc/analyzer/kf-lang-cp.cc b/gcc/analyzer/kf-lang-cp.cc
index 393b4f25e79..cfb0584979b 100644
--- a/gcc/analyzer/kf-lang-cp.cc
+++ b/gcc/analyzer/kf-lang-cp.cc
@@ -35,6 +35,38 @@ along with GCC; see the file COPYING3. If not see
#if ENABLE_ANALYZER
+/* Return true if CALL is a non-allocating operator new or operator new []
+ that contains no user-defined args, i.e. having any signature of:
+
+ - void* operator new (std::size_t count, void* ptr);
+ - void* operator new[] (std::size_t count, void* ptr);
+
+ See https://en.cppreference.com/w/cpp/memory/new/operator_new. */
+
+bool is_placement_new_p (const gcall *call)
+{
+ gcc_assert (call);
+ tree fndecl = gimple_call_fndecl (call);
+
+ if (!fndecl || TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
+ /* Give up on overloaded operator new. */
+ return false;
+
+ if (!is_named_call_p (fndecl, "operator new", call, 2)
+ && !is_named_call_p (fndecl, "operator new []", call, 2))
+ return false;
+
+ /* We must distinguish between an allocating non-throwing new
+ and a non-allocating new.
+
+ The former might have one of the following signatures :
+ void* operator new (std::size_t count, const std::nothrow_t& tag);
+ void* operator new[] (std::size_t count, const std::nothrow_t& tag);
+ Whereas a placement new would take a pointer. */
+ tree arg1_type = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fndecl)));
+ return TREE_CODE (TREE_VALUE (arg1_type)) == POINTER_TYPE;
+}
+
namespace ana {
/* Implementations of specific functions. */
@@ -46,7 +78,11 @@ class kf_operator_new : public known_function
public:
bool matches_call_types_p (const call_details &cd) const final override
{
- return cd.num_args () == 1;
+ return (cd.num_args () == 1
+ && cd.arg_is_size_p (0))
+ || (cd.num_args () == 2
+ && cd.arg_is_size_p (0)
+ && POINTER_TYPE_P (cd.get_arg_type (1)));
}
void impl_call_pre (const call_details &cd) const final override
@@ -54,28 +90,74 @@ public:
region_model *model = cd.get_model ();
region_model_manager *mgr = cd.get_manager ();
const svalue *size_sval = cd.get_arg_svalue (0);
- const region *new_reg
- = model->get_or_create_region_for_heap_alloc (size_sval, cd.get_ctxt ());
- if (cd.get_lhs_type ())
+ region_model_context *ctxt = cd.get_ctxt ();
+ const gcall *call = cd.get_call_stmt ();
+
+ /* If the call was actually a placement new, check that accessing
+ the buffer lhs is placed into does not result in out-of-bounds. */
+ if (is_placement_new_p (call))
{
+ const region *ptr_reg = cd.maybe_get_arg_region (1);
+ if (ptr_reg && cd.get_lhs_type ())
+ {
+ const region *base_reg = ptr_reg->get_base_region ();
+ const svalue *num_bytes_sval = cd.get_arg_svalue (0);
+ const region *sized_new_reg = mgr->get_sized_region (base_reg,
+ cd.get_lhs_type (),
+ num_bytes_sval);
+ model->check_region_for_write (sized_new_reg,
+ nullptr,
+ ctxt);
const svalue *ptr_sval
- = mgr->get_ptr_svalue (cd.get_lhs_type (), new_reg);
+ = mgr->get_ptr_svalue (cd.get_lhs_type (), sized_new_reg);
cd.maybe_set_lhs (ptr_sval);
+ }
+ }
+ /* If the call is an allocating new, then create a heap allocated
+ region. */
+ else
+ {
+ const region *new_reg
+ = model->get_or_create_region_for_heap_alloc (size_sval, ctxt);
+ if (cd.get_lhs_type ())
+ {
+ const svalue *ptr_sval
+ = mgr->get_ptr_svalue (cd.get_lhs_type (), new_reg);
+ cd.maybe_set_lhs (ptr_sval);
+ }
+ }
+ }
+
+ void impl_call_post (const call_details &cd) const final override
+ {
+ region_model *model = cd.get_model ();
+ region_model_manager *mgr = cd.get_manager ();
+ tree callee_fndecl = cd.get_fndecl_for_call ();
+ region_model_context *ctxt = cd.get_ctxt ();
+
+ /* If the call is guaranteed to return nonnull
+ then add a nonnull constraint to the allocated region. */
+ if (!TREE_NOTHROW (callee_fndecl) && flag_exceptions)
+ {
+ const svalue *null_sval
+ = mgr->get_or_create_null_ptr (cd.get_lhs_type ());
+ const svalue *result
+ = model->get_store_value (cd.get_lhs_region (), ctxt);
+ model->add_constraint (result, NE_EXPR, null_sval, ctxt);
}
}
};
-/* Handler for "operator delete", both the sized and unsized variants
- (2 arguments and 1 argument respectively), and for "operator delete []" */
+/* Handler for "operator delete" and for "operator delete []",
+ both the sized and unsized variants
+ (2 arguments and 1 argument respectively). */
class kf_operator_delete : public known_function
{
public:
- kf_operator_delete (unsigned num_args) : m_num_args (num_args) {}
-
bool matches_call_types_p (const call_details &cd) const final override
{
- return cd.num_args () == m_num_args;
+ return cd.num_args () == 1 or cd.num_args () == 2;
}
void impl_call_post (const call_details &cd) const final override
@@ -86,12 +168,10 @@ public:
{
/* If the ptr points to an underlying heap region, delete it,
poisoning pointers. */
- model->unbind_region_and_descendents (freed_reg, POISON_KIND_FREED);
+ model->unbind_region_and_descendents (freed_reg, POISON_KIND_DELETED);
}
}
-private:
- unsigned m_num_args;
};
/* Populate KFM with instances of known functions relating to C++. */
@@ -101,9 +181,8 @@ register_known_functions_lang_cp (known_function_manager
&kfm)
{
kfm.add ("operator new", make_unique<kf_operator_new> ());
kfm.add ("operator new []", make_unique<kf_operator_new> ());
- kfm.add ("operator delete", make_unique<kf_operator_delete> (1));
- kfm.add ("operator delete", make_unique<kf_operator_delete> (2));
- kfm.add ("operator delete []", make_unique<kf_operator_delete> (1));
+ kfm.add ("operator delete", make_unique<kf_operator_delete> ());
+ kfm.add ("operator delete []", make_unique<kf_operator_delete> ());
}
} // namespace ana
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index 494a9cdf149..a358794356e 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -499,6 +499,7 @@ public:
case POISON_KIND_UNINIT:
return OPT_Wanalyzer_use_of_uninitialized_value;
case POISON_KIND_FREED:
+ case POISON_KIND_DELETED:
return OPT_Wanalyzer_use_after_free;
case POISON_KIND_POPPED_STACK:
return OPT_Wanalyzer_use_of_pointer_in_stale_stack_frame;
@@ -531,6 +532,15 @@ public:
m_expr);
}
break;
+ case POISON_KIND_DELETED:
+ {
+ diagnostic_metadata m;
+ m.add_cwe (416); /* "CWE-416: Use After Free". */
+ return warning_meta (rich_loc, m, get_controlling_option (),
+ "use after %<delete%> of %qE",
+ m_expr);
+ }
+ break;
case POISON_KIND_POPPED_STACK:
{
/* TODO: which CWE? */
@@ -555,6 +565,9 @@ public:
case POISON_KIND_FREED:
return ev.formatted_print ("use after %<free%> of %qE here",
m_expr);
+ case POISON_KIND_DELETED:
+ return ev.formatted_print ("use after %<delete%> of %qE here",
+ m_expr);
case POISON_KIND_POPPED_STACK:
return ev.formatted_print
("dereferencing pointer %qE to within stale stack frame",
@@ -2210,7 +2223,7 @@ region_model::get_rvalue_1 (path_var pv,
region_model_context *ctxt) const
case MEM_REF:
{
const region *ref_reg = get_lvalue (pv, ctxt);
- return get_store_value (ref_reg, ctxt);
+ return get_store_value (ref_reg, ctxt); // INFO get store value of
field_region(cast_region(heap_allocated_region(19), ‘struct A’), ‘int’, ‘int
A::x’)
}
case OBJ_TYPE_REF:
{
@@ -2321,6 +2334,16 @@ region_model::get_store_value (const region *reg,
= m_store.get_any_binding (m_mgr->get_store_manager (), reg);
if (sval)
{
+/* if (m_constraints->sval_constrained_p (sval))
+ {
+ equiv_class_id sval_ecid = equiv_class_id::null ();
+ if (m_constraints->get_equiv_class_by_svalue (sval, &sval_ecid))
+ {
+ const equiv_class& sval_ec = sval_ecid.get_obj(*m_constraints);
+ if (sval_ec.get_any_constant () != NULL_TREE)
+ sval = sval_ec.m_cst_sval;
+ }
+ } */
if (reg->get_type ())
sval = m_mgr->get_or_create_cast (reg->get_type (), sval);
return sval;
@@ -2363,6 +2386,28 @@ region_model::get_store_value (const region *reg,
== RK_GLOBALS)
return get_initial_value_for_global (reg);
+ /* If there exists a NULL constraint on the parent region,
+ then do not create a poisoned_uninit value. */
+ if (reg->get_kind () == RK_FIELD || reg->get_kind () == RK_ELEMENT)
+ {
+ const region *base_reg = reg->get_base_region ();
+ const svalue *base_sval
+ = m_store.get_any_binding (m_mgr->get_store_manager (), base_reg);
+ if (base_sval)
+ {
+ if (m_constraints->sval_constrained_p (base_sval))
+ {
+ equiv_class_id sval_ecid = equiv_class_id::null ();
+ if (m_constraints->get_equiv_class_by_svalue (base_sval,
&sval_ecid))
+ {
+ const equiv_class& sval_ec =
sval_ecid.get_obj(*m_constraints);
+ if (const_tree cst = sval_ec.get_any_constant ())
+ if (::zerop (cst))
+ check_poisoned = false;
+ }
+ }
+ }
+ }
return m_mgr->get_or_create_initial_value (reg, check_poisoned);
}
@@ -3582,6 +3627,27 @@ region_model::eval_condition (const svalue *lhs,
}
}
+ /* Attempt to unwrap cast if there is one, and the types match. */
+ tree lhs_type = lhs->get_type ();
+ tree rhs_type = rhs->get_type ();
+ if (lhs_type && rhs_type)
+ {
+ const unaryop_svalue *lhs_un_op = dyn_cast <const unaryop_svalue *> (lhs);
+ const unaryop_svalue *rhs_un_op = dyn_cast <const unaryop_svalue *> (rhs);
+ if (lhs_un_op && CONVERT_EXPR_CODE_P (lhs_un_op->get_op ())
+ && rhs_un_op && CONVERT_EXPR_CODE_P (rhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs_un_op->get_arg (), op, rhs_un_op->get_arg ());
+
+ else if (lhs_un_op && CONVERT_EXPR_CODE_P (lhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs_un_op->get_arg (), op, rhs);
+
+ else if (rhs_un_op && CONVERT_EXPR_CODE_P (rhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs, op, rhs_un_op->get_arg ());
+ }
+
/* Otherwise, try constraints.
Cast to const to ensure we don't change the constraint_manager as we
do this (e.g. by creating equivalence classes). */
diff --git a/gcc/analyzer/sm-malloc.cc b/gcc/analyzer/sm-malloc.cc
index ec763254b29..567237cf1ae 100644
--- a/gcc/analyzer/sm-malloc.cc
+++ b/gcc/analyzer/sm-malloc.cc
@@ -759,7 +759,7 @@ public:
override
{
if (change.m_old_state == m_sm.get_start_state ()
- && unchecked_p (change.m_new_state))
+ && (unchecked_p (change.m_new_state) || nonnull_p (change.m_new_state)))
// TODO: verify that it's the allocation stmt, not a copy
return label_text::borrow ("allocated here");
if (unchecked_p (change.m_old_state)
@@ -1915,11 +1915,16 @@ malloc_state_machine::on_stmt (sm_context *sm_ctxt,
return true;
}
- if (is_named_call_p (callee_fndecl, "operator new", call, 1))
- on_allocator_call (sm_ctxt, call, &m_scalar_delete);
- else if (is_named_call_p (callee_fndecl, "operator new []", call, 1))
- on_allocator_call (sm_ctxt, call, &m_vector_delete);
- else if (is_named_call_p (callee_fndecl, "operator delete", call, 1)
+ if (!is_placement_new_p (call))
+ {
+ bool returns_nonnull = !TREE_NOTHROW (callee_fndecl) &&
flag_exceptions;
+ if (is_named_call_p (callee_fndecl, "operator new"))
+ on_allocator_call (sm_ctxt, call, &m_scalar_delete,
returns_nonnull);
+ else if (is_named_call_p (callee_fndecl, "operator new []"))
+ on_allocator_call (sm_ctxt, call, &m_vector_delete,
returns_nonnull);
+ }
+
+ if (is_named_call_p (callee_fndecl, "operator delete", call, 1)
|| is_named_call_p (callee_fndecl, "operator delete", call, 2))
{
on_deallocator_call (sm_ctxt, node, call,
diff --git a/gcc/analyzer/svalue.cc b/gcc/analyzer/svalue.cc
index 064627f3dcc..35eb8307b20 100644
--- a/gcc/analyzer/svalue.cc
+++ b/gcc/analyzer/svalue.cc
@@ -970,6 +970,8 @@ poison_kind_to_str (enum poison_kind kind)
return "uninit";
case POISON_KIND_FREED:
return "freed";
+ case POISON_KIND_DELETED:
+ return "deleted";
case POISON_KIND_POPPED_STACK:
return "popped stack";
}
diff --git a/gcc/analyzer/svalue.h b/gcc/analyzer/svalue.h
index 5492b1e0b7c..263a0d7af6f 100644
--- a/gcc/analyzer/svalue.h
+++ b/gcc/analyzer/svalue.h
@@ -350,6 +350,9 @@ enum poison_kind
/* For use to describe freed memory. */
POISON_KIND_FREED,
+ /* For use to describe deleted memory. */
+ POISON_KIND_DELETED,
+
/* For use on pointers to regions within popped stack frames. */
POISON_KIND_POPPED_STACK
};
diff --git a/gcc/testsuite/g++.dg/analyzer/new-2.C
b/gcc/testsuite/g++.dg/analyzer/new-2.C
new file mode 100644
index 00000000000..9e0315b3f44
--- /dev/null
+++ b/gcc/testsuite/g++.dg/analyzer/new-2.C
@@ -0,0 +1,70 @@
+// { dg-additional-options "-O0 -fno-analyzer-suppress-followups -fexceptions"
}
+#include <new>
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_spurious_null_warning_throwing ()
+{
+ int *x = new int; /* { dg-bogus "dereference of possibly-NULL" } */
+ int *y = new int (); /* { dg-bogus "dereference of possibly-NULL"
"non-throwing" } */
+ int *arr = new int[3]; /* { dg-bogus "dereference of possibly-NULL" } */
+ A *a = new A (); /* { dg-bogus "dereference of possibly-NULL" "throwing new
cannot be null" } */
+
+ int z = *y + 2;
+ z = *x + 4; /* { dg-bogus "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1
} */
+ z = arr[0] + 4; /* { dg-bogus "dereference of possibly-NULL" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* }
.-1 } */
+
+ delete a;
+ delete y;
+ delete x;
+ delete[] arr;
+}
+
+void test_default_initialization ()
+{
+ int *y = ::new int;
+ int *x = ::new int (); /* { dg-bogus "dereference of possibly-NULL
'operator new" } */
+
+ int b = *x + 3; /* { dg-bogus "dereference of possibly-NULL" } */
+ /* { dg-bogus "use of uninitialized ‘*x’" "" { target *-*-* } .-1 } */
+ int a = *y + 2; /* { dg-bogus "dereference of possibly-NULL 'y'" } */
+ /* { dg-warning "use of uninitialized value '\\*y'" "no default init" {
target *-*-* } .-1 } */
+
+ delete x;
+ delete y;
+}
+
+/* From clang core.uninitialized.NewArraySize
+new[] should not be called with an undefined size argument */
+
+void test_garbage_new_array ()
+{
+ int n;
+ int *arr = ::new int[n]; /* { dg-warning "use of uninitialized value 'n'" }
*/
+ arr[0] = 7;
+ ::delete[] arr; /* no warnings emitted here either */
+}
+
+void test_nonthrowing ()
+{
+ int* x = new(std::nothrow) int;
+ int* y = new(std::nothrow) int();
+ int* arr = new(std::nothrow) int[10];
+
+ int z = *y + 2; /* { dg-warning "dereference of NULL 'y'" } */
+ /* { dg-bogus "use of uninitialized value '\\*y'" "" { xfail *-*-* } .-1 } */
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1
} */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* }
.-1 } */
+
+ delete y;
+ delete x;
+ delete[] arr;
+}
diff --git a/gcc/testsuite/g++.dg/analyzer/noexcept-new.C
b/gcc/testsuite/g++.dg/analyzer/noexcept-new.C
new file mode 100644
index 00000000000..4a5f526b0f3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/analyzer/noexcept-new.C
@@ -0,0 +1,48 @@
+/* { dg-additional-options "-O0 -fno-exceptions
-fno-analyzer-suppress-followups" } */
+#include <new>
+
+/* Test non-throwing variants of operator new */
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_throwing ()
+{
+ int* x = new int;
+ int* y = new int(); /* { dg-warning "dereference of possibly-NULL" } */
+ int* arr = new int[10];
+ A *a = new A(); /* { dg-warning "dereference of possibly-NULL" } */
+
+ int z = *y + 2;
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1
} */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* }
.-1 } */
+ a->y = a->x + 3;
+
+ delete a;
+ delete y;
+ delete x;
+ delete[] arr;
+}
+
+void test_nonthrowing ()
+{
+ int* x = new(std::nothrow) int;
+ int* y = new(std::nothrow) int();
+ int* arr = new(std::nothrow) int[10];
+
+ int z = *y + 2; /* { dg-warning "dereference of NULL 'y'" } */
+ /* { dg-bogus "use of uninitialized value '\\*y'" "" { xfail *-*-* } .-1 } */
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1
} */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* }
.-1 } */
+
+ delete y;
+ delete x;
+ delete[] arr;
+}
diff --git a/gcc/testsuite/g++.dg/analyzer/out-of-bounds-placement-new.C
b/gcc/testsuite/g++.dg/analyzer/out-of-bounds-placement-new.C
index d3076c3cf25..33872e6ddab 100644
--- a/gcc/testsuite/g++.dg/analyzer/out-of-bounds-placement-new.C
+++ b/gcc/testsuite/g++.dg/analyzer/out-of-bounds-placement-new.C
@@ -14,6 +14,6 @@ struct int_and_addr {
int test (int_container ic)
{
- int_and_addr *iaddr = new (ic.addr ()) int_and_addr;
+ int_and_addr *iaddr = new (ic.addr ()) int_and_addr; /* { dg-warning
"stack-based buffer overflow" } */
return iaddr->i;
}
diff --git a/gcc/testsuite/g++.dg/analyzer/placement-new-size.C
b/gcc/testsuite/g++.dg/analyzer/placement-new-size.C
new file mode 100644
index 00000000000..4536d361b4a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/analyzer/placement-new-size.C
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-Wno-placement-new
-Wno-analyzer-use-of-uninitialized-value" } */
+
+#include <new>
+#include <stdint.h>
+
+extern int get_buf_size ();
+
+void var_too_short ()
+{
+ int8_t s;
+ int64_t *lp = new (&s) int64_t; /* { dg-warning "stack-based buffer
overflow" } */
+ /* { dg-warning "allocated buffer size is not a multiple of the pointee's
size" "" { target *-*-* } .-1 } */
+}
+
+void static_buffer_too_short ()
+{
+ int n = 16;
+ int buf[n];
+ int *p = new (buf) int[n + 1]; /* { dg-warning "stack-based buffer overflow"
} */
+}
+
+void symbolic_buffer_too_short ()
+{
+ int n = get_buf_size ();
+ char buf[n];
+ char *p = new (buf) char[n + 10]; /* { dg-warning "stack-based buffer
overflow" } */
+}
diff --git a/gcc/testsuite/g++.dg/analyzer/placement-new.C
b/gcc/testsuite/g++.dg/analyzer/placement-new.C
index 89055491a48..8edd778131b 100644
--- a/gcc/testsuite/g++.dg/analyzer/placement-new.C
+++ b/gcc/testsuite/g++.dg/analyzer/placement-new.C
@@ -1,3 +1,5 @@
+/* { dg-additional-options "-Wno-free-nonheap-object -fexceptions" } */
+
#include <new>
/* Placement new. */
@@ -14,15 +16,101 @@ void test_2 (void)
{
char buf[sizeof(int) * 10];
int *p = new(buf) int[10];
-}
+} // { dg-prune-output "-Wfree-nonheap-object" }
/* Delete of placement new. */
void test_3 (void)
{
char buf[sizeof(int)]; // { dg-message "region created on stack here" }
- int *p = new(buf) int (42);
+ int *p = new (buf) int (42);
+ delete p; // { dg-warning "memory on the stack" }
+}
+
+// { dg-prune-output "-Wfree-nonheap-object" }
+
+void test_4 (void)
+{
+ int buf[5]; // { dg-message "region created on stack here" }
+ int *p = new (&buf[2]) int (42);
delete p; // { dg-warning "memory on the stack" }
}
+
// { dg-prune-output "-Wfree-nonheap-object" }
+
+void test_write_placement_after_delete (void)
+{
+ short *s = ::new short;
+ short *lp = ::new (s) short;
+ ::delete s;
+ *lp = 12; /* { dg-warning "use after 'delete' of 'lp'" "write placement new
after buffer deletion" } */
+}
+
+void test_read_placement_after_delete (void)
+{
+ short *s = ::new short;
+ short *lp = ::new (s) short;
+ ::delete s;
+ short m = *lp; // { dg-warning "use after 'delete' of 'lp'" "read placement
new after buffer deletion" }
+}
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_use_placement_after_destruction (void)
+{
+ A a;
+ int *lp = ::new (&a.y) int;
+ *lp = 2; /* { dg-bogus "-Wanalyzer-use-of-uninitialized-value" } */
+ a.~A();
+ int m = *lp; /* { dg-warning "use of uninitialized value '\\*lp'" "use of
placement after the underlying buffer was destructed." } */
+}
+
+void test_initialization_through_placement (void)
+{
+ int x;
+ int *p = ::new (&x) int;
+ *p = 10;
+ int z = x + 2; /* { dg-bogus "use of uninitialized value 'x'" "x has been
initialized through placement pointer" } */
+}
+
+void test_partial_initialization_through_placement (void)
+{
+ char buf[4];
+ char *p = ::new (&buf[2]) char;
+ *p = 10;
+ char *y = ::new (&buf[0]) char;
+ char z = buf[2] + 2; /* { dg-bogus "use of uninitialized value" } */
+ z = *y + 2; /* { dg-warning "use of uninitialized value '\\*y'" "y has only
been partially initialized" } */
+}
+
+
+void test_delete_placement (void)
+{
+ A *a = ::new A; /* { dg-bogus "use of possibly-NULL 'operator new(8)' where
non-null expected" "throwing new cannot be null" } */
+ int *z = ::new (&a->y) int;
+ a->~A(); // deconstruct properly
+ ::operator delete (a);
+ ::operator delete (z); /* { dg-warning "use after 'delete' of 'z'" } */
+}
+
+void test_delete_placement_2 (void)
+{
+ A *a = ::new A; /* { dg-bogus "use of possibly-NULL 'operator new(8)' where
non-null expected" "throwing new cannot be null" } */
+ int *z = ::new (&a->y) int;
+ delete a;
+ ::operator delete (z); /* { dg-warning "use after 'delete' of 'z'" } */
+}
+
+void test_use_placement_after_deallocation (void)
+{
+ A *a = ::new A ();
+ int *lp = ::new (&a->y) int;
+ *lp = 2; /* { dg-bogus "use of uninitialized value" } */
+ ::operator delete (a);
+ int m = *lp; /* { dg-warning "use after 'delete' of 'lp'" "use of placement
after the underlying buffer was deallocated." } */
+}
--
2.34.1
