From: benjamin priour <priour...@gmail.com> Script contrib/check_GNU_style.sh complains about there being a space before a left square bracket ("operator new []"). Though, it is actually within a literal string, and the space is required to correctly detect the function.
Succesfully regstrapped on x86_64-linux-gnu against trunk 3c776fdf1a8. Is it OK for trunk ? Benjamin. --- 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'. gcc/analyzer/ChangeLog: PR analyzer/105948 * 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 above function. * kf-lang-cp.cc (is_placement_new_p): Returns true if the gcall is recognized as a placement new. * region-model.cc (region_model::eval_condition): Now recursively call itself if one the operand is wrapped in a cast. * sm-malloc.cc (malloc_state_machine::on_stmt): Added recognition of placement new. gcc/testsuite/ChangeLog: PR analyzer/105948 * g++.dg/analyzer/out-of-bounds-placement-new.C: New test. * 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. Signed-off-by: benjamin priour <priour...@gmail.com> --- gcc/analyzer/analyzer.h | 1 + gcc/analyzer/call-details.cc | 11 +++ gcc/analyzer/call-details.h | 1 + gcc/analyzer/kf-lang-cp.cc | 85 +++++++++++++++++-- gcc/analyzer/region-model.cc | 21 +++++ gcc/analyzer/sm-malloc.cc | 17 ++-- gcc/testsuite/g++.dg/analyzer/new-2.C | 50 +++++++++++ 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 | 63 +++++++++++++- 11 files changed, 312 insertions(+), 14 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 579517c23e6..b86e5cac74d 100644 --- a/gcc/analyzer/analyzer.h +++ b/gcc/analyzer/analyzer.h @@ -391,6 +391,7 @@ 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 17edaf26276..01f061d774e 100644 --- a/gcc/analyzer/call-details.cc +++ b/gcc/analyzer/call-details.cc @@ -152,6 +152,17 @@ 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 14a206ff5d6..aac2b7d33d8 100644 --- a/gcc/analyzer/call-details.h +++ b/gcc/analyzer/call-details.h @@ -55,6 +55,7 @@ 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..258d92919d7 100644 --- a/gcc/analyzer/kf-lang-cp.cc +++ b/gcc/analyzer/kf-lang-cp.cc @@ -35,6 +35,34 @@ along with GCC; see the file COPYING3. If not see #if ENABLE_ANALYZER +/* Return TRUE if CALL is non-allocating operator new or operator new[]*/ + +bool is_placement_new_p (const gcall *call) +{ + gcc_assert (call); + + tree fndecl = gimple_call_fndecl (call); + if (!fndecl) + return false; + + if (!is_named_call_p (fndecl, "operator new", call, 2) + && !is_named_call_p (fndecl, "operator new []", call, 2)) + return false; + tree arg1 = gimple_call_arg (call, 1); + + if (!POINTER_TYPE_P (TREE_TYPE (arg1))) + return false; + + /* Sadly, for non-throwing new, the second argument type + is not REFERENCE_TYPE but also POINTER_TYPE + so a simple check is out of the way. */ + tree identifier = TYPE_IDENTIFIER (TREE_TYPE (TREE_TYPE (arg1))); + if (!identifier) + return true; + const char *name = IDENTIFIER_POINTER (identifier); + return 0 != strcmp (name, "nothrow_t"); +} + namespace ana { /* Implementations of specific functions. */ @@ -46,7 +74,7 @@ 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.num_args () == 2; } void impl_call_pre (const call_details &cd) const final override @@ -54,13 +82,60 @@ 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 is an allocating new, then create a heap allocated + region. */ + if (!is_placement_new_p (call)) + { + 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); + } + } + /* If the call was actually a placement new, check that accessing + the buffer lhs is placed into does not result in out-of-bounds. */ + else { + 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); + } + } + } + + 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 (TREE_TYPE (callee_fndecl)) && flag_exceptions) + { + const svalue *nonnull + = 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, nonnull, ctxt); } } }; diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc index 187013a37cc..599178e3d86 100644 --- a/gcc/analyzer/region-model.cc +++ b/gcc/analyzer/region-model.cc @@ -3479,6 +3479,27 @@ 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 a8c63eb1ce8..41c313c07dd 100644 --- a/gcc/analyzer/sm-malloc.cc +++ b/gcc/analyzer/sm-malloc.cc @@ -754,7 +754,7 @@ 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) @@ -1910,11 +1910,16 @@ 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/testsuite/g++.dg/analyzer/new-2.C b/gcc/testsuite/g++.dg/analyzer/new-2.C new file mode 100644 index 00000000000..4e696040a54 --- /dev/null +++ b/gcc/testsuite/g++.dg/analyzer/new-2.C @@ -0,0 +1,50 @@ +// { dg-additional-options "-O0" } + +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" } */ + + 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 */ +} 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..7699cd99cff --- /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-warning "use of uninitialized value '\\*y'" "" { target *-*-* } .-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..810944cd137 --- /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 "../../gcc.dg/analyzer/analyzer-decls.h" + +extern int get_buf_size (); + +void var_too_short () +{ + short s; + long *lp = new (&s) long; /* { 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..c0cf7ec4c48 100644 --- a/gcc/testsuite/g++.dg/analyzer/placement-new.C +++ b/gcc/testsuite/g++.dg/analyzer/placement-new.C @@ -14,15 +14,74 @@ 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" } */ +} \ No newline at end of file -- 2.34.1