Attached is an updated patch with some the changes you suggested.
I also moved the new functions from decl.c to init.c because they
logically seem to belong there.
The suggested changes resulted in introducing the checking code
into split_nonconstant_init() in cp/typeck2.c in addition to
build_vec_init(). I would expect it to be preferable to check
in as few places as possible so I attach an alternate version
of the patch without this proliferation of call (the tests and
the documentation changes are the same so I excluded those).
Let me know which of the two approaches you prefer and/or if
you have any other requests or suggestions.
Martin
On 04/07/2016 06:05 PM, Martin Sebor wrote:
I've spent a ton of time trying to implement the suggested
changes (far too much in large part because of my own mistakes)
but I don't think they will work. I'll try to clean up what
I have and post it for review. I wanted to respond to this
how in case you have some suggestions or concerns with the
direction I'm taking in the meantime.
But if even a few MB seems too strict, I would find having even
an exceedingly liberal limit (say 1GB) much preferable to none
at all as it makes it possible to exercise boundary conditions
such as the size overflow problem you noted below.
That sounds reasonable, as long as users with unusual needs can adjust
it with a flag, but even so I'm nervous about doing this in stage 4. It
certainly isn't a regression.
I'm not comfortable adding a new option at this stage. I'm also
not sure that an option to impose a static limit is the best
solution. It seems that if we go to the trouble of making the limit
customizable it should be possible to change it without recompiling
everything (e.g., on ELF, we could check for a weak function and
call it to get the most up-to-date limit).
Let me restore the 4.9.3 behavior by setting the VLA size limit to
SIZE_MAX / 2 (that fixes the other regression that I just raised
in c++/70588 for the record).
I don't think modifying build_vec_init() alone would be sufficient.
For example, the function isn't called for a VLA with a constant
bound like this one:
int A [2][N] = { 1, 2, 3, 4 };
That seems like a bug, due to array_of_runtime_bound_p returning false
for that array.
It seems that a complete fix would involve (among other things)
replacing calls to array_of_runtime_bound_p with
variably_modified_type_p or similar since the N3639 arrays are
just a subset of those accepted by G++. Unfortunately, that has
other repercussions (e.g., c++70555).
I replaced the call to array_of_runtime_bound_p in build_vec_init
with one to variably_modified_type_p to get around the above.
That works, but it's only good for checking for excess
initializers in build_vec_init. It's too late to check for
overflow in the VLA bounds because by that time the code to
allocate the stack has already been emitted.
Also, I think we should check for invalid bounds in
compute_array_index_type, next to the UBsan code. Checking bounds only
from cp_finish_decl means that we don't check uses of VLA types other
than variable declarations.
I don't see how to make this work. compute_array_index_type
doesn't have access to the CONSTRUCTOR for the initializer of
the VLA the initializer hasn't been parsed yet). Without it
it's not possible to detect VLA size overflow in cases such
as in:
T a [][N] = { { ... }, { ... } };
where the number of top-level elements determines whether or
not the size of the whole VLA would overflow or exceed the
maximum.
Given this, I believe the check does need to be implemented
somewhere in cp_finish_decl or one of the functions it calls
(such as check_initializer) and emitted before build_vec_init
is called or the initializer code it creates is emitted.
You mean VLA typedefs? That's true, though I have consciously
avoided dealing with those. They're outlawed in N3639 and so
I've been focusing just on variables. But since GCC accepts
VLA typedefs too I was thinking I would bring them up at some
point in the future to decide what to do about them.
And cast to pointer to VLAs. But for non-variable cases we don't care
about available stack, so we wouldn't want your allocation limit to
apply.
I don't want to implement it now, but I think the same limit
should apply in all cases, otherwise code remains susceptible
to unsigned integer wrapping. For example:
extern size_t N;
typedef int A [N];
int *a = (int*)malloc (sizeof (A)); // possible wraparound
a [N - 1] = 0; // out-of-bounds write
It seems that the typedef will need to be accepted (in case it's
unused) but the runtime sizeof would need to do the checking and
potentially throw. I haven't thought through the ramifications
yet.
As for where to add the bounds checking code, I also at first
thought of checking the bounds parallel to the UBSan code in
compute_array_index_type() and even tried that approach. The
problem with it is that it only considers one array dimension
at a time, without the knowledge of the others. As a result,
as noted in sanitizer/70051, it doesn't correctly detect
overflows in the bounds of multidimensional VLAs.
It doesn't, but I don't see why it couldn't. It should be fine to check
each dimension for overflow separately; if an inner dimension doesn't
overflow, we can go on and consider the outer dimension.
As I explained above, I don't see how to make this work.
Incidentally, I was wondering if it would make sense to use the
overflowing calculation for both TYPE_SIZE and the sanity check when
we're doing both.
I'm not sure what you mean here. Can you elaborate?
+ /* Avoid instrumenting constexpr functions. Those must
+ be checked statically, and the (non-constexpr) dynamic
+ instrumentation would cause them to be rejected. */
Hmm, this sounds wrong; constexpr functions can also be called with
non-constant arguments, and the instrumentation should be folded away
when evaluating a call with constant arguments.
You're right that constexpr functions should be checked as
well. Unfortunately, at present, due to c++/70507 the check
(or rather the call to __builtin_mul_overflow) isn't folded
away and we end up with error: call to internal function.
Ah, sure. It should be pretty simple to teach the constexpr code how to
handle that built-in.
I'd be glad to do this work but I don't believe I can get it done
in time for 6.0.
Martin
PR c++/69517 - [5/6 regression] SEGV on a VLA with excess initializer elements
PR c++/70019 - VLA size overflow not detected
gcc/testsuite/ChangeLog:
2016-04-10 Martin Sebor <mse...@redhat.com>
PR c++/69517
PR c++/70019
* c-c++-common/ubsan/vla-1.c (main): Catch exceptions.
* g++.dg/cpp1y/vla11.C: New test.
* g++.dg/cpp1y/vla12.C: New test.
* g++.dg/cpp1y/vla13.C: New test.
* g++.dg/cpp1y/vla14.C: New test.
* g++.dg/cpp1y/vla3.C: Restore deleted test.
* gcc/testsuite/g++.dg/init/array24.C: Fully brace VLA initializer.
* g++.dg/ubsan/vla-1.C: Disable exceptions.
gcc/cp/ChangeLog:
2016-04-10 Martin Sebor <mse...@redhat.com>
PR c++/69517
PR c++/70019
* cp-tree.h (throw_bad_array_length, build_vla_check): Declare new
functions.
* decl.c (check_initializer, cp_finish_decl): Call them.
(reshape_init_r): Reject incompletely braced intializer-lists
for VLAs.
* init.c (throw_bad_array_length, build_vla_check)
(build_vla_size_check, build_vla_init_check): Define new functions.
(build_vec_init): Use variably_modified_type_p() to detect a VLA.
Call throw_bad_array_length() and build_vla_check().
* typeck2.c (split_nonconstant_init_1): Use variably_modified_type_p()
to detect a VLA.
(store_init_value): Same.
(split_nonconstant_init): Handle excess elements in string literal
initializers for VLAs.
gcc/doc/ChangeLog:
2016-04-10 Martin Sebor <mse...@redhat.com>
PR c++/69517
PR c++/70019
* extend.texi (Variable Length): Document C++ specifics.
libstdc++-v3/ChangeLog:
2016-04-10 Martin Sebor <mse...@redhat.com>
PR c++/69517
* testsuite/25_algorithms/rotate/moveable2.cc: Make sure VLA
upper bound is positive.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index b7b770f..1d726fd 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5978,6 +5978,7 @@ extern tree build_value_init_noctor (tree, tsubst_flags_t);
extern tree get_nsdmi (tree, bool);
extern tree build_offset_ref (tree, tree, bool,
tsubst_flags_t);
+extern tree throw_bad_array_length (void);
extern tree throw_bad_array_new_length (void);
extern tree build_new (vec<tree, va_gc> **, tree, tree,
vec<tree, va_gc> **, int,
@@ -5999,6 +6000,7 @@ extern tree scalar_constant_value (tree);
extern tree decl_really_constant_value (tree);
extern int diagnose_uninitialized_cst_or_ref_member (tree, bool, bool);
extern tree build_vtbl_address (tree);
+extern tree build_vla_check (tree, tree = NULL_TREE);
/* in lex.c */
extern void cxx_dup_lang_specific_decl (tree);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 9260f4c..c8caeea 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -5864,6 +5864,16 @@ reshape_init_r (tree type, reshape_iter *d, bool first_initializer_p,
}
}
+ if (variably_modified_type_p (type, NULL_TREE))
+ {
+ /* Require VLAs to have their initializers fully braced
+ to avoid initializing the wrong elements. */
+ if (complain & tf_error)
+ error ("missing braces around initializer for a variable length "
+ "array %qT", type);
+ return error_mark_node;
+ }
+
warning (OPT_Wmissing_braces, "missing braces around initializer for %qT",
type);
}
@@ -6167,6 +6177,33 @@ check_initializer (tree decl, tree init, int flags, vec<tree, va_gc> **cleanups)
&& PAREN_STRING_LITERAL_P (DECL_INITIAL (decl)))
warning (0, "array %qD initialized by parenthesized string literal %qE",
decl, DECL_INITIAL (decl));
+
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && variably_modified_type_p (type, NULL_TREE)
+ && !processing_template_decl)
+ {
+ /* Statically check for overflow in VLA bounds and build
+ an expression that checks at runtime whether the VLA
+ is erroneous due to invalid (runtime) bounds.
+ Another expression to check for excess initializers
+ is built in build_vec_init. */
+ tree check = build_vla_check (TREE_TYPE (decl), NULL_TREE);
+
+ if (flag_exceptions && current_function_decl
+ /* Avoid instrumenting constexpr functions for now.
+ Those must be checked statically, and the (non-
+ constexpr) dynamic instrumentation would cause
+ them to be rejected. See c++/70507. */
+ && !DECL_DECLARED_CONSTEXPR_P (current_function_decl))
+ {
+ /* Use the runtime check only when exceptions are enabled.
+ Otherwise let bad things happen... */
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
+ }
init = NULL;
}
}
@@ -6809,6 +6846,38 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
cleanups = make_tree_vector ();
init = check_initializer (decl, init, flags, &cleanups);
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && variably_modified_type_p (type, NULL_TREE)
+ && !processing_template_decl
+ && !init)
+ {
+ /* Statically check for overflow in VLA bounds and build
+ an expression that checks whether the VLA is erroneous
+ at runtime. A runtime check for the bounds of
+ initialized VLAs along with excess initializer
+ elements is built in build_vec_init() for initializer
+ lists and in split_nonconstant_init() for string
+ literals. */
+ tree check = build_vla_check (type);
+
+ if (flag_exceptions
+ && current_function_decl
+ /* Avoid instrumenting constexpr functions. Those must
+ be checked statically for now since the (non-constexpr)
+ dynamic instrumentation would cause them to be rejected
+ due to c++/70507. */
+ && !DECL_DECLARED_CONSTEXPR_P (current_function_decl))
+ {
+ /* Use the runtime check only when exceptions are enabled.
+ Otherwise let bad things happen (though perhaps emitting
+ a trap would be appropriate). */
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
+ }
+
/* Handle:
[dcl.init]
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 5997d53..8e33df0 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2262,6 +2262,20 @@ diagnose_uninitialized_cst_or_ref_member (tree type, bool using_new, bool compla
return diagnose_uninitialized_cst_or_ref_member_1 (type, type, using_new, complain);
}
+/* Call __cxa_throw_bad_array_length to indicate that the size calculation
+ in the bounds of a variable length array overflowed. */
+
+tree
+throw_bad_array_length (void)
+{
+ tree fn = get_identifier ("__cxa_throw_bad_array_length");
+ if (!get_global_value_if_present (fn, &fn))
+ fn = push_throw_library_fn (fn, build_function_type_list (void_type_node,
+ NULL_TREE));
+
+ return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
+}
+
/* Call __cxa_bad_array_new_length to indicate that the size calculation
overflowed. Pretend it returns sizetype so that it plays nicely in the
COND_EXPR. */
@@ -3819,15 +3833,20 @@ build_vec_init (tree base, tree maxindex, tree init,
&& from_array != 2)
init = TARGET_EXPR_INITIAL (init);
+ /* Is ATYPE a variable modified type such as a VLA with either
+ a const or non-const major bound. */
+ bool vartype_p = (!TREE_CONSTANT (maxindex)
+ || variably_modified_type_p (atype, NULL_TREE));
+
/* If we have a braced-init-list, make sure that the array
is big enough for all the initializers. */
bool length_check = (init && TREE_CODE (init) == CONSTRUCTOR
&& CONSTRUCTOR_NELTS (init) > 0
- && !TREE_CONSTANT (maxindex));
+ && vartype_p);
if (init
&& TREE_CODE (atype) == ARRAY_TYPE
- && TREE_CONSTANT (maxindex)
+ && !vartype_p
&& (from_array == 2
? vec_copy_assign_is_trivial (inner_elt_type, init)
: !TYPE_NEEDS_CONSTRUCTING (type))
@@ -3925,7 +3944,7 @@ build_vec_init (tree base, tree maxindex, tree init,
/* Should we try to create a constant initializer? */
bool try_const = (TREE_CODE (atype) == ARRAY_TYPE
- && TREE_CONSTANT (maxindex)
+ && !vartype_p
&& (init ? TREE_CODE (init) == CONSTRUCTOR
: (type_has_constexpr_default_constructor
(inner_elt_type)))
@@ -3973,6 +3992,24 @@ build_vec_init (tree base, tree maxindex, tree init,
}
/* Don't check an array new when -fno-exceptions. */
}
+ else if (flag_exceptions
+ && current_function_decl
+ /* Avoid instrumenting constexpr functions. Those must
+ be checked statically for now since the (non-constexpr)
+ dynamic instrumentation would cause them to be rejected
+ due to c++/70507. */
+ && !DECL_DECLARED_CONSTEXPR_P (current_function_decl))
+ {
+ /* Use the runtime check only when exceptions are enabled.
+ Otherwise let bad things happen (though perhaps emitting
+ a trap would be appropriate). */
+ tree check = build_vla_check (atype, init);
+
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
else if (flag_sanitize & SANITIZE_BOUNDS
&& do_ubsan_in_current_function ())
{
@@ -4709,3 +4746,293 @@ build_vec_delete (tree base, tree maxindex,
return rval;
}
+
+
+/* The implementation of build_vla_check() that recursively builds
+ an expression to determine whether the VLA TYPE is erroneous due
+ either to its bounds being invalid or to integer overflow in
+ the computation of its total size.
+ CHECK is the boolean expression being built, initialized to
+ boolean_false_node.
+ VLASIZE is used internally to pass the incrementally computed
+ size of the VLA object down to its recursive invocations.
+ MAX_VLASIZE is the maximum valid size of the VLA in bytes.
+ CST_SIZE is the product of the VLA's constant dimensions. */
+
+static tree
+build_vla_size_check (tree check,
+ tree type,
+ tree vlasize,
+ tree max_vlasize,
+ offset_int *cst_size)
+{
+ tree vmul = builtin_decl_explicit (BUILT_IN_MUL_OVERFLOW);
+
+ tree vlasizeaddr = build_unary_op (input_location, ADDR_EXPR, vlasize, 0);
+
+ bool overflow = false;
+
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ /* Compute the upper bound of this array type. */
+ tree inner_nelts = array_type_nelts_top (type);
+ tree inner_nelts_cst = maybe_constant_value (inner_nelts);
+
+ if (TREE_CODE (inner_nelts_cst) == INTEGER_CST)
+ {
+ /* The upper bound is a constant expression. Compute the product
+ of the constant upper bounds seen so far so that overflow can
+ be diagnosed. */
+ offset_int result = wi::mul (wi::to_offset (inner_nelts_cst),
+ *cst_size, SIGNED, &overflow);
+ *cst_size = overflow ? 0 : result;
+ }
+
+ /* Check for overflow in the VLAs (runtime) upper bounds. */
+ tree vflowcheck = build_call_expr (vmul, 3, inner_nelts,
+ vlasize, vlasizeaddr);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, vflowcheck);
+
+ /* Recursively check for overflow in the remaining major bounds. */
+ check = build_vla_size_check (check, TREE_TYPE (type),
+ vlasize, max_vlasize,
+ cst_size);
+ }
+ else
+ {
+ /* Get the size of the VLA element type in bytes. */
+ tree typesize = TYPE_SIZE_UNIT (type);
+
+ /* See if the size, when multipled by the product of the VLA's
+ constant dimensions, is within range of size_t. If not,
+ the VLA is definitely erroneous amd must be diagnosed at
+ compile time. */
+ offset_int result = wi::mul (wi::to_offset (typesize), *cst_size,
+ SIGNED, &overflow);
+ *cst_size = overflow ? 0 : result;
+
+ /* Multiply the (non-constant) VLA size so far by the element size,
+ checking for overflow, and replacing the value of vlasize with
+ the product in the absence of overflow. This size is the total
+ runtime size of the VLA in bytes. */
+ tree vflowcheck = build_call_expr (vmul, 3, typesize,
+ vlasize, vlasizeaddr);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, vflowcheck);
+
+ /* Check to see if the final VLA size exceeds the maximum. */
+ tree sizecheck = fold_build2 (LT_EXPR, boolean_type_node,
+ max_vlasize, vlasize);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, sizecheck);
+
+ /* Also check to see if the final array size is zero (the size
+ is unsigned so the earlier overflow check detects negative
+ values as well. */
+ tree zerocheck = fold_build2 (EQ_EXPR, boolean_type_node,
+ vlasize, size_zero_node);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, zerocheck);
+ }
+
+ /* Diagnose overflow determined at compile time. */
+ if (overflow)
+ {
+ error ("integer overflow in variable array size");
+ /* Reset to suppress any further diagnostics. */
+ *cst_size = 0;
+ }
+
+ return check;
+}
+
+/* The implementation of build_vla_check() that recursively builds
+ an expression to determine whether the VLA initializer-list for
+ TYPE is erroneous due to excess initializers.
+ CHECK is the boolean expression being built, initialized to
+ the result of build_vla_size_check().
+ INIT is the VLA initializer expression to check against TYPE.
+ On the first (non-recursive) call, INIT_ELTS is set either to 1,
+ or to the number of elements in the initializer-list for VLAs
+ of unspecified (major) bound. On subsequent (recursive) calls.
+ it is set to NULL and computed from the number of elements in
+ the (nested) initializer-list.
+*/
+
+static tree
+build_vla_init_check (tree check, tree type, tree init, tree init_elts)
+{
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ /* Compute the upper bound of this array type unless it has
+ already been computed by the caller for an array of unspecified
+ bound, as in 'T a[];' */
+ tree inner_nelts = init_elts ? init_elts : array_type_nelts_top (type);
+
+ size_t len;
+
+ if (TREE_CODE (init) == CONSTRUCTOR)
+ {
+ /* The initializer of this array is itself an array. Build
+ an expression to check if the number of elements in the
+ initializer array exceeds the upper bound of the type
+ of the object being initialized. */
+ if (vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (init))
+ {
+ len = v->length ();
+ tree initelts = build_int_cstu (size_type_node, len);
+ tree initcheck = fold_build2 (LT_EXPR, boolean_type_node,
+ inner_nelts, initelts);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, initcheck);
+
+ constructor_elt *ce;
+ HOST_WIDE_INT i;
+
+ /* Iterate over all non-empty initializers in this array,
+ recursively building expressions to see if the elements
+ of each are in excess of the corresponding (runtime)
+ bound of the array type. */
+ FOR_EACH_VEC_SAFE_ELT (v, i, ce)
+ check = build_vla_init_check (check, TREE_TYPE (type),
+ ce->value, NULL_TREE);
+ }
+ }
+ else if (TREE_CODE (init) == STRING_CST
+ && (len = TREE_STRING_LENGTH (init)))
+ {
+ /* The initializer of this array is a string. */
+ tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (init)));
+ len /= TYPE_PRECISION (ctype) / BITS_PER_UNIT;
+
+ /* A C++ string literal initializer must have at most as many
+ characters as there are elements in the array, including
+ the terminating NUL. */
+ tree initelts = build_int_cstu (size_type_node, len);
+ tree initcheck = fold_build2 (LT_EXPR, boolean_type_node,
+ inner_nelts, initelts);
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, initcheck);
+ }
+ else if (TREE_CODE (init) == ERROR_MARK)
+ {
+ // No checking is possible.
+ check = boolean_false_node;
+ }
+ else
+ {
+ /* What's this array initializer? */
+ gcc_unreachable ();
+ }
+ }
+
+ return check;
+}
+
+/* Build an expression to determine whether the VLA TYPE is erroneous.
+ INIT is the VLA initializer expression or NULL_TREE when the VLA is
+ not initialized. */
+
+/* Build an expression to determine whether the VLA TYPE is erroneous.
+ INIT is the VLA initializer expression or NULL_TREE when the VLA is
+ not initialized. */
+
+tree
+build_vla_check (tree type, tree init /* = NULL_TREE */)
+{
+ tree check = boolean_false_node;
+
+ /* The product of all constant dimensions of the VLA, initialized
+ to either 1 in the common case or to the number of elements in
+ the VLA's initializer-list for VLAs of unspecified (major)
+ bound. */
+ offset_int cst_size = 1;
+
+ /* The initial size of the VLA to start the computation of the total
+ size with. Like CST_SIZE above, initialized to 1 or the number
+ of elements in the VLA's initializer-list for VLAs of unspecified
+ bound. */
+ tree initial_size = size_one_node;
+
+ /* For a VLA of unspecified (major) bound, the number of elements
+ it is initialized with determined from the initializer-list. */
+ tree initial_elts = NULL_TREE;
+
+ if (init)
+ {
+ /* Determine the upper bound of the VLA of unspecified bound,
+ as in 'T a[];' if this is such a VLA. Such a VLA can be
+ initialized with any number of elements but the number of
+ elements so determined must be used to check the total size
+ of the VLA. */
+ gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
+
+ if (tree dom = TYPE_DOMAIN (type))
+ if (tree max = TYPE_MAX_VALUE (dom))
+ if (integer_zerop (max))
+ {
+ if (TREE_CODE (init) == CONSTRUCTOR)
+ {
+ vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (init);
+
+ /* Since the upper bound of every array must be positive
+ a VLA with an unspecified major bound must be initized
+ by a non-empty initializer list. */
+ gcc_assert (v != NULL);
+
+ cst_size = v->length ();
+ }
+ else if (TREE_CODE (init) == STRING_CST)
+ {
+ /* The initializer is a (possibly empty) string consisting
+ at a minumum of one character, the terminating NUL.
+ This condition implies a definition like
+ char s [][N] = "";
+ which is an error but even though it has been diagnosed
+ by this point the initializer still winds up here. */
+ size_t nchars = TREE_STRING_LENGTH (init);
+ tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (init)));
+ nchars /= TYPE_PRECISION (ctype) / BITS_PER_UNIT;
+
+ cst_size = nchars + 1;
+ }
+
+ initial_elts = wide_int_to_tree (size_type_node, cst_size);
+ initial_size = initial_elts;
+ }
+ }
+
+ /* Build a variable storing the total runtime size of the VLA and
+ initialize it either to 1 (in the common case) or to the number
+ of topmost elements in the initializer-list when the VLA is
+ an array of unspecified (major) bound. */
+ tree vlasize = build_decl (input_location,
+ VAR_DECL, NULL_TREE, sizetype);
+ DECL_ARTIFICIAL (vlasize) = 1;
+ DECL_IGNORED_P (vlasize) = 1;
+ DECL_CONTEXT (vlasize) = current_function_decl;
+ DECL_INITIAL (vlasize) = initial_size;
+ vlasize = pushdecl (vlasize);
+ add_decl_expr (vlasize);
+
+ /* Impose a lenient limit on the size of the biggest VLA in bytes.
+ FIXME: Tighten up the limit to make it more useful and make it
+ configurable for users with unusual requirements. */
+ tree max_vlasize
+ = fold_build2 (RSHIFT_EXPR, size_type_node,
+ build_all_ones_cst (size_type_node),
+ integer_one_node);
+
+ /* Build an expression that checks the runtime bounds of the VLA
+ for invalid values and the total size of the VLA for overflow. */
+ check = build_vla_size_check (check, type, vlasize, max_vlasize, &cst_size);
+
+ if (wi::ltu_p (wi::to_offset (max_vlasize), cst_size))
+ {
+ /* Issue the warning only in the "topmost" (non-recursive) call
+ to avoid duplicating diagnostics. This is only a warning to
+ allow programs to be portable to more permissive environments. */
+ warning (OPT_Wvla, "size of variable length array exceeds maximum "
+ "of %qE bytes", max_vlasize);
+ }
+
+ if (init)
+ {
+ /* Build an expression that checks the VLA initializer expression
+ against the type of the VLA for excess elements. */
+ check = build_vla_init_check (check, type, init, initial_elts);
+ }
+
+ return check;
+}
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index b921689..092d512 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -603,7 +603,7 @@ split_nonconstant_init_1 (tree dest, tree init)
array_type_p = true;
if ((TREE_SIDE_EFFECTS (init)
&& TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
- || array_of_runtime_bound_p (type))
+ || variably_modified_type_p (type, NULL_TREE))
{
/* For an array, we only need/want a single cleanup region rather
than one per element. */
@@ -749,7 +749,26 @@ split_nonconstant_init (tree dest, tree init)
TREE_READONLY (dest) = 0;
}
else
- code = build2 (INIT_EXPR, TREE_TYPE (dest), dest, init);
+ {
+ tree type = TREE_TYPE (dest);
+
+ if (TREE_CODE (init) == STRING_CST
+ && TREE_CODE (type) == ARRAY_TYPE
+ && variably_modified_type_p (type, NULL_TREE))
+ {
+ /* Statically check for overflow in VLA bounds and build
+ an expression that checks whether the VLA is erroneous
+ at runtime due to excess elements in the string literal. */
+ tree check = build_vla_check (type, init);
+
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
+
+ code = build2 (INIT_EXPR, TREE_TYPE (dest), dest, init);
+ }
return code;
}
@@ -845,7 +864,8 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
will perform the dynamic initialization. */
if (value != error_mark_node
&& (TREE_SIDE_EFFECTS (value)
- || array_of_runtime_bound_p (type)
+ || variably_modified_type_p (type, NULL_TREE)
|| ! reduced_constant_expression_p (value)))
return split_nonconstant_init (decl, value);
/* If the value is a constant, just put it in DECL_INITIAL. If DECL
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 6e27029..616479d 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -1634,14 +1634,48 @@ foo (int n)
You can use the function @code{alloca} to get an effect much like
variable-length arrays. The function @code{alloca} is available in
many other C implementations (but not in all). On the other hand,
-variable-length arrays are more elegant.
+variable-length arrays are available in GCC for all targets and
+provide type safety.
There are other differences between these two methods. Space allocated
with @code{alloca} exists until the containing @emph{function} returns.
The space for a variable-length array is deallocated as soon as the array
name's scope ends, unless you also use @code{alloca} in this scope.
-You can also use variable-length arrays as arguments to functions:
+Unlike GCC, G++ instruments variable-length arrays (@xref{Variable Length})
+with checks for erroneous uses: when a variable-length array object is
+created its runtime bounds are checked to detect non-positive values,
+integer overflows, sizes in excess of 1 MB, and excess initializers.
+When an erroneous variable-length array is detected the runtime arranges
+for an exception to be thrown that matches a handler of type
+@code{std::bad_array_length}.
+
+Also unlike GCC, G++ allows variable-length arrays to be initialized.
+However, unlike initializer lists for ordinary multidimensional arrays,
+those for multidimensional variable-length arrays must be enclosed in
+pairs of curly braces delimiting each sequence of values to use to
+initialize each subarray. Initializer lists that aren't unambiguously
+enclosed in braces are rejected with an error. For example, in the
+following function, the initializer list for the ordinary @code{array}
+is accepted even though it isn't fully enclosed in braces. The same
+initializer list, however, wouldn't be accepted for a multidimensional
+variable-length array. To initialize the variable-length array @code{vla},
+the elements of the subarray @code{vla[m]} must be enclosed in braces
+as shown. As with ordinary arrays, elements that aren't initialized
+explicitly are default-initialized.
+
+@smallexample
+void
+foo (int m, int n)
+@{
+ int array[2][3] = @{ 1, 2, 4, 5, 6 @};
+ int vla[m][n] = @{ @{ 1, 2 @}, @{ 4, 5, 6 @} @};
+@}
+@end smallexample
+
+
+In C programs (but not in C++) variable-length arrays can also be declared
+as function arguments:
@smallexample
struct entry
diff --git a/gcc/testsuite/c-c++-common/ubsan/vla-1.c b/gcc/testsuite/c-c++-common/ubsan/vla-1.c
index 52ade3a..27ef110 100644
--- a/gcc/testsuite/c-c++-common/ubsan/vla-1.c
+++ b/gcc/testsuite/c-c++-common/ubsan/vla-1.c
@@ -87,18 +87,24 @@ fn12 (void)
int
main (void)
{
- fn1 ();
- fn2 ();
- fn3 ();
- fn4 ();
- fn5 ();
- fn6 ();
- fn7 ();
- fn8 ();
- fn9 ();
- fn10 ();
- fn11 ();
- fn12 ();
+#if __cplusplus
+# define TRY(stmt) do { try { stmt; } catch (...) { } } while (0)
+#else
+# define TRY(stmt) stmt
+#endif
+
+ TRY (fn1 ());
+ TRY (fn2 ());
+ TRY (fn3 ());
+ TRY (fn4 ());
+ TRY (fn5 ());
+ TRY (fn6 ());
+ TRY (fn7 ());
+ TRY (fn8 ());
+ TRY (fn9 ());
+ TRY (fn10 ());
+ TRY (fn11 ());
+ TRY (fn12 ());
return 0;
}
diff --git a/gcc/testsuite/g++.dg/cpp1y/vla11.C b/gcc/testsuite/g++.dg/cpp1y/vla11.C
new file mode 100644
index 0000000..af9624a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/vla11.C
@@ -0,0 +1,711 @@
+// PR c++/69517 - [5/6 regression] SEGV on a VLA with excess initializer
+// elements
+// PR c++/70019 - VLA size overflow not detected
+//
+// Runtime test to verify that attempting to either construct a VLA with
+// erroneous bounds, or initialize one with an initializer-list that
+// contains more elements than the VLA's non-constant (runtime) bounds
+// causes an exception to be thrown. Test also verifies that valid
+// VLAs and their initializers don't cause such an exception.
+
+// { dg-do run { target c++11 } }
+// { dg-additional-options "-Wno-vla" }
+
+#pragma GCC diagnostic ignored "-Wvla"
+
+#define INT_MAX __INT_MAX__
+#define LONG_MAX __LONG_MAX__
+#define SIZE_MAX __SIZE_MAX__
+#define UINT_MAX (~0U)
+#define ULONG_MAX (~0LU)
+
+#define INT_MIN (-__INT_MAX__ - 1)
+#define LONG_MIN (-__LONG_MAX__ - 1)
+
+// The size of the largest allowed VLA in bytes. Bigger objects
+// cause an exception to be thrown. Unless the maximum size is
+// obscenely large, smaller objects should be successfully created
+// provided there's enough stack space. See TEST_NEAR_VLA_MAX_SIZE
+// below.
+#define MAX (__SIZE_MAX__ / 2)
+
+// Define to non-zero to exercise very large VLAs with size just
+// below the implementation-defined maximum.
+#define TEST_NEAR_VLA_MAX_SIZE 0
+
+// Define to zero to enable tests that cause an ICE due to c++/58646.
+#define BUG_58646 1
+
+// Helper macro to make it possible to pass as one multpile arguments
+// to another macro.
+#define Init(...) __VA_ARGS__
+
+typedef __SIZE_TYPE__ size_t;
+
+// Incremented for each test failure.
+int fail;
+
+// Used to convert a constant array dimension to a non-constant one.
+template <class T>
+T d (T n)
+{
+ return n;
+}
+
+// Verify either that an expected exception has been thrown or that
+// one hasn't been thrown if one isn't expected.
+int __attribute__ ((noclone, noinline))
+sink (void *p, int line, bool expect, const char *expr)
+{
+ if (!p != expect)
+ {
+ __builtin_printf ("line %i: Assertion failed: '%s': "
+ "exception unexpectedly %sthrown\n",
+ line, expr, !p ? "" : "not ");
+ ++fail;
+ }
+ else
+ {
+#if defined DEBUG && DEBUG
+ __builtin_printf ("line %i: Assertion passed: '%s': "
+ "exception %sthrown as expected\n",
+ line, expr, !p ? "" : "not ");
+#endif
+ }
+ return 0;
+}
+
+#define _CAT(name, line) name ## line
+#define CAT(name, line) _CAT (name, line)
+
+#define STR(...) #__VA_ARGS__
+
+// Type to exercise VLA with. TYPESIZE is the size of the type in bytes.
+// Using a template serves two purposes. First, it makes it possible to
+// parameterize the test on VLAs of different size. Second, it verifies
+// that the checking code can deal with templates (i.e., completes
+// the element type of the VLA when necessary).
+template <unsigned TypeSize>
+struct alignas (TypeSize) TestType
+{
+ char data;
+};
+
+// Test function invoked with a pointer to each test case. Must
+// return a value though what value doesn't matter.
+int __attribute__ ((noclone, noinline))
+tester (int (*testcase)(const char*),
+ const char *str, int line, bool expect)
+{
+ try
+ {
+ return testcase (str);
+ }
+ catch (...)
+ {
+ return sink (0, line, expect, str);
+ }
+}
+
+// Macro to define a unique specialization of a function template to
+// exercise a VLA of type T, rank N, with dimensions given by Dims
+// and initializer Init. Expect is true when the VLA initialization
+// is expected to trigger an exception.
+// The macro creates a unique global dummy int object and initializes
+// it with the result of the function. The dummy object servers no
+// other purpose but to call the function. The function verifies
+// the expected postconditions.
+#define TEST(TypeSize, Dims, Init, Expect) \
+ static int CAT (testcase, __LINE__)(const char *str) \
+ { \
+ TestType<TypeSize> vla Dims Init; \
+ static_assert (sizeof (TestType<TypeSize>) == TypeSize, \
+ "wrong test type size"); \
+ return sink (vla, __LINE__, Expect, str); \
+ } \
+ const int CAT (dummy, __LINE__) \
+ = tester (CAT (testcase, __LINE__), \
+ "T<" #TypeSize "> a" #Dims " " STR (Init) ";", \
+ __LINE__, Expect)
+
+
+// Create and run a test function exercising a VLA definition
+// of one of the following forms:
+// TestType<Size> VLA Dims; // uninitialized (with Init ())
+// or:
+// TestType<Size> VLA Dims Init; // initialized (with = Init ({...})
+//
+// +-- Element Size (in Bytes)
+// | +-- VLA Dimensions (constant as in [3], otherwise d(3))
+// | | +-- VLA Initializer Expression (if any)
+// | | | +-- Expect Exception
+// | | | |
+// V V V V
+TEST (1, [d(0)], Init (/* none*/), true); // uninitialized
+
+#if !BUG_58646
+// The following causes an ICE due to c++/58646.
+TEST (1, [d(0)], Init ({}), true);
+#endif
+TEST (1, [d(0)], Init ({1}), true); // initialized with " {1}"
+TEST (1, [d(0)], = Init ({1}), true); // initialized with "= {1}"
+
+TEST (1, [d(1)], Init (), false);
+TEST (1, [d(1)], Init ({}), false);
+TEST (1, [d(1)], = Init ({}), false);
+TEST (1, [d(1)], Init ({1}), false);
+TEST (1, [d(1)], = Init ({1}), false);
+TEST (1, [d(1)], Init ({1, 2}), true);
+TEST (1, [d(1)], = Init ({1, 2}), true);
+
+TEST (1, [d(2)], Init (), false);
+TEST (1, [d(2)], Init ({}), false);
+TEST (1, [d(2)], Init ({1}), false);
+TEST (1, [d(2)], Init ({1, 2}), false);
+TEST (1, [d(2)], Init ({1, 2, 3}), true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+// Very large but not erroneous one dimensional VLAs.
+TEST (1, [d(MAX)], Init (), false);
+TEST (1, [d(MAX)], Init ({}), false);
+TEST (1, [d(MAX)], Init ({1}), false);
+TEST (1, [d(MAX)], Init ({1, 2}), false);
+TEST (1, [d(MAX)], Init ({1, 2, 3}), false);
+
+TEST ( 2, [d(MAX / 2)], Init (), false);
+TEST ( 4, [d(MAX / 4)], Init (), false);
+TEST ( 8, [d(MAX / 8)], Init (), false);
+TEST (16, [d(MAX / 16)], Init (), false);
+TEST (32, [d(MAX / 32)], Init (), false);
+TEST (64, [d(MAX / 64)], Init (), false);
+#endif // TEST_NEAR_VLA_MAX_SIZE
+
+// One dimensional VLAs with a negative upper bound.
+TEST (1, [d(LONG_MIN)], Init (), true);
+TEST (1, [d(INT_MIN)], Init (), true);
+TEST (1, [d(-1234)], Init (), true);
+TEST (1, [d(-1)], Init (), true);
+
+// Excessively large one dimensional VLAs.
+TEST ( 1, [d(MAX + 1)], Init (), true);
+TEST ( 2, [d(MAX)], Init (), true);
+TEST ( 4, [d(MAX / 2)], Init (), true);
+TEST ( 4, [d(MAX / 3)], Init (), true);
+TEST ( 8, [d(MAX / 2)], Init (), true);
+TEST ( 8, [d(MAX / 3)], Init (), true);
+TEST ( 8, [d(MAX / 4)], Init (), true);
+TEST ( 8, [d(MAX / 5)], Init (), true);
+TEST ( 8, [d(MAX / 6)], Init (), true);
+TEST ( 8, [d(MAX / 7)], Init (), true);
+TEST (16, [d(MAX / 15)], Init (), true);
+TEST (32, [d(MAX / 31)], Init (), true);
+TEST (64, [d(MAX / 63)], Init (), true);
+TEST ( 1, [d(SIZE_MAX)], Init (), true);
+
+TEST (1, [d(LONG_MIN)], Init ({}), true);
+TEST (1, [d(INT_MIN)], Init ({}), true);
+TEST (1, [d(-1)], Init ({}), true);
+
+TEST (1, [d(SIZE_MAX)], Init ({}), true);
+
+TEST (1, [d(LONG_MIN)], Init ({0}), true);
+TEST (1, [d(INT_MIN)], Init ({0}), true);
+TEST (1, [d(-1)], Init ({0}), true);
+
+TEST (1, [d(SIZE_MAX)], Init ({0}), true);
+
+TEST ( 1, [d(SIZE_MAX/2) + 1], Init (), true);
+TEST ( 2, [d(SIZE_MAX/4) + 1], Init (), true);
+TEST ( 4, [d(SIZE_MAX/8) + 1], Init (), true);
+TEST ( 8, [d(SIZE_MAX/16) + 1], Init (), true);
+TEST (16, [d(SIZE_MAX/32) + 1], Init (), true);
+
+TEST ( 1, [d(SIZE_MAX/2) + 1], Init ({1}), true);
+TEST ( 2, [d(SIZE_MAX/4) + 1], Init ({1, 2}), true);
+TEST ( 4, [d(SIZE_MAX/8) + 1], Init ({1, 2, 3}), true);
+TEST ( 8, [d(SIZE_MAX/16) + 1], Init ({1, 2, 3, 4}), true);
+TEST (16, [d(SIZE_MAX/32) + 1], Init ({1, 2, 3, 4, 5}), true);
+
+// Two dimensional VLAs with one constant bound.
+
+TEST (1, [1][d(0)], Init (), true);
+
+#if !BUG_58646
+// The following causes an ICE due to c++/58646.
+TEST (1, [1][d(0)], Init ({}), true);
+#endif
+TEST (1, [ ][d(0)], Init ({{1}}), true); // unspecified bound
+TEST (1, [1][d(0)], Init ({{1}}), true);
+
+TEST (1, [1][d(1)], Init (), false);
+TEST (1, [1][d(1)], Init ({{1}}), false);
+TEST (1, [1][d(1)], Init ({{1, 2}}), true);
+TEST (1, [ ][d(1)], Init ({{1, 2}}), true);
+
+TEST (1, [1][d(2)], Init (), false);
+TEST (1, [1][d(2)], Init ({{1}}), false);
+TEST (1, [1][d(2)], Init ({{1, 2}}), false);
+TEST (1, [ ][d(2)], Init ({{1, 2}}), false);
+TEST (1, [1][d(2)], Init ({{1, 2, 3}}), true);
+TEST (1, [ ][d(2)], Init ({{1, 2, 3}}), true);
+
+TEST (1, [2][d(1)], Init (), false);
+TEST (1, [2][d(1)], Init ({{1}}), false);
+TEST (1, [ ][d(1)], Init ({{1}}), false);
+TEST (1, [2][d(1)], Init ({{1}, {2}}), false);
+TEST (1, [ ][d(1)], Init ({{1}, {2}}), false);
+TEST (1, [2][d(1)], Init ({{1, 2}}), true);
+TEST (1, [ ][d(1)], Init ({{1, 2}}), true);
+TEST (1, [2][d(1)], Init ({{1}, {2, 3}}), true);
+TEST (1, [ ][d(1)], Init ({{1}, {2, 3}}), true);
+TEST (1, [2][d(1)], Init ({{1, 2, 3}}), true);
+TEST (1, [ ][d(1)], Init ({{1, 2, 3}}), true);
+TEST (1, [2][d(1)], Init ({{1, 2, 3}, {4}}), true);
+TEST (1, [ ][d(1)], Init ({{1, 2, 3}, {4}}), true);
+TEST (1, [2][d(1)], Init ({{1, 2}, {3, 4}}), true);
+TEST (1, [ ][d(1)], Init ({{1, 2}, {3, 4}}), true);
+
+TEST (1, [2][d(2)], Init (), false);
+TEST (1, [2][d(2)], Init ({{1}}), false);
+TEST (1, [2][d(2)], Init ({{1, 2}}), false);
+TEST (1, [2][d(2)], Init ({{1, 2}, {3}}), false);
+TEST (1, [2][d(2)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [2][d(2)], Init ({{1}, {2, 3, 4}}), true);
+TEST (1, [2][d(2)], Init ({{1}, {2, 3, 4, 5}}), true);
+TEST (1, [2][d(2)], Init ({{1, 2}, {3, 4, 5}}), true);
+TEST (1, [2][d(2)], Init ({{1, 2, 3}, {4, 5}}), true);
+TEST (1, [2][d(2)], Init ({{1, 2, 3}, {4, 5, 6}}), true);
+
+TEST (1, [2][d(3)], Init (), false);
+TEST (1, [2][d(3)], Init ({{1}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2}, {3}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [2][d(3)], Init ({{1}, {2, 3, 4}}), false);
+TEST (1, [2][d(3)], Init ({{1}, {2, 3, 4, 5}}), true);
+TEST (1, [2][d(3)], Init ({{1, 2}, {3, 4, 5}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2, 3}, {4, 5}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2, 3}, {4, 5, 6}}), false);
+TEST (1, [2][d(3)], Init ({{1, 2, 3}, {4, 5, 6, 7}}), true);
+TEST (1, [2][d(3)], Init ({{1, 2, 3, 4}, {5, 6, 7}}), true);
+TEST (1, [2][d(3)], Init ({{1, 2, 3, 4, 5}, {6, 7}}), true);
+TEST (1, [2][d(3)], Init ({{1, 2, 3, 4, 5, 6}, {7}}), true);
+TEST (1, [2][d(3)], Init ({{1, 2, 3, 4, 5, 6, 7}}), true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+TEST (1, [1][d(MAX)], Init (), false);
+# if !BUG_58646
+// The following causes an ICE due to c++/58646.
+TEST (1, [1][d(MAX)], Init ({}), false);
+# endif
+TEST (1, [1][d(MAX)], Init ({{1}}), false);
+TEST (1, [1][d(MAX)], Init ({{1, 2}}), false);
+TEST (1, [1][d(MAX)], Init ({{1, 2, 3}}), false);
+TEST (1, [1][d(MAX)], Init ({{1, 2, 3, 4}}), false);
+
+TEST (1, [2][d(MAX / 2)], Init (), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2, 3}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2, 3, 4}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1}, {2}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1}, {2, 3}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2}, {3}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2, 3}, {4}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2, 3}, {4, 5}}), false);
+TEST (1, [2][d(MAX / 2)], Init ({{1, 2, 3}, {4, 5, 6}}), false);
+#endif // TEST_NEAR_VLA_MAX_SIZE
+
+// Excessively large two dimensional VLAs.
+TEST (1, [1][d(LONG_MIN)], Init (), true);
+TEST (1, [1][d(INT_MIN)], Init (), true);
+TEST (1, [1][d(-1)], Init (), true);
+
+TEST (1, [1][d(SIZE_MAX)], Init (), true);
+
+#if !BUG_58646
+// The following cause an ICE due to c++/58646.
+TEST (1, [1][d(LONG_MIN)], Init ({}), true);
+TEST (1, [1][d(INT_MIN)], Init ({}), true);
+TEST (1, [1][d(-1)], Init ({}), true);
+TEST (1, [1][d(SIZE_MAX)], Init ({}), true);
+#endif
+
+TEST (1, [1][d(LONG_MIN)], Init ({{0}}), true);
+TEST (1, [1][d(INT_MIN)], Init ({{0}}), true);
+TEST (1, [1][d(-1)], Init ({{0}}), true);
+TEST (1, [1][d(SIZE_MAX)], Init ({{0}}), true);
+
+TEST (1, [d(LONG_MIN)][1], Init (), true);
+TEST (1, [d(INT_MIN)][1], Init (), true);
+TEST (1, [d(-1)][1], Init (), true);
+TEST (1, [d(SIZE_MAX)][1], Init (), true);
+
+TEST (1, [d(LONG_MIN)][1], Init ({}), true);
+TEST (1, [d(INT_MIN)][1], Init ({}), true);
+TEST (1, [d(-1)][1], Init ({}), true);
+TEST (1, [d(SIZE_MAX)][1], Init ({}), true);
+
+TEST (1, [d(LONG_MIN)][1], Init ({{0}}), true);
+TEST (1, [d(INT_MIN)][1], Init ({{0}}), true);
+TEST (1, [d(-1)][1], Init ({{0}}), true);
+TEST (1, [d(SIZE_MAX)][1], Init ({{0}}), true);
+
+// Two dimensional VLAs with no constant bound.
+TEST (1, [d(0)][d(0)], Init (), true);
+TEST (1, [d(0)][d(0)], Init ({}), true);
+#if !BUG_58646
+// The following cause an ICE due to c++/58646.
+TEST (1, [d(0)][d(0)], Init ({{}}), true);
+TEST (1, [d(0)][d(0)], Init ({{}, {}}), true);
+#endif
+
+TEST (1, [d(0)][d(0)], Init ({{1}}), true);
+TEST (1, [d(0)][d(0)], Init ({{1, 2}}), true);
+#if !BUG_58646
+TEST (1, [d(0)][d(0)], Init ({{1}, {}}), true);
+TEST (1, [d(0)][d(0)], Init ({{}, {1}}), true);
+#endif
+
+TEST (1, [d(1)][d(0)], Init (), true);
+TEST (1, [d(1)][d(0)], Init ({}), true);
+TEST (1, [d(1)][d(0)], Init ({{1}}), true);
+
+TEST (1, [d(1)][d(1)], Init (), false);
+TEST (1, [d(1)][d(1)], Init ({{1}}), false);
+TEST (1, [d(1)][d(1)], Init ({{1, 2}}), true);
+
+TEST (1, [d(1)][d(2)], Init (), false);
+TEST (1, [d(1)][d(2)], Init ({{1}}), false);
+TEST (1, [d(1)][d(2)], Init ({{1, 2}}), false);
+TEST (1, [d(1)][d(2)], Init ({{1, 2, 3}}), true);
+
+TEST (1, [d(2)][d(1)], Init (), false);
+TEST (1, [d(2)][d(1)], Init ({{1}}), false);
+TEST (1, [d(2)][d(1)], Init ({{1}, {2}}), false);
+TEST (1, [d(2)][d(1)], Init ({{1, 2}}), true);
+TEST (1, [d(2)][d(1)], Init ({{1}, {2, 3}}), true);
+TEST (1, [d(2)][d(1)], Init ({{1, 2, 3}}), true);
+TEST (1, [d(2)][d(1)], Init ({{1, 2, 3}, {4}}), true);
+TEST (1, [d(2)][d(1)], Init ({{1, 2}, {3, 4}}), true);
+
+TEST (1, [d(2)][d(2)], Init (), false);
+TEST (1, [d(2)][d(2)], Init ({{1}}), false);
+TEST (1, [d(2)][d(2)], Init ({{1, 2}}), false);
+TEST (1, [d(2)][d(2)], Init ({{1, 2}, {3}}), false);
+TEST (1, [d(2)][d(2)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [d(2)][d(2)], Init ({{1}, {2, 3, 4}}), true);
+TEST (1, [d(2)][d(2)], Init ({{1}, {2, 3, 4, 5}}), true);
+TEST (1, [d(2)][d(2)], Init ({{1, 2}, {3, 4, 5}}), true);
+TEST (1, [d(2)][d(2)], Init ({{1, 2, 3}, {4, 5}}), true);
+TEST (1, [d(2)][d(2)], Init ({{1, 2, 3}, {4, 5, 6}}), true);
+
+TEST (1, [d(2)][d(3)], Init (), false);
+TEST (1, [d(2)][d(3)], Init ({{1}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2}, {3}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1}, {2, 3, 4}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1}, {2, 3, 4, 5}}), true);
+TEST (1, [d(2)][d(3)], Init ({{1, 2}, {3, 4, 5}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3}, {4, 5}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3}, {4, 5, 6}}), false);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3}, {4, 5, 6, 7}}), true);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3, 4}, {5, 6, 7}}), true);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3, 4, 5}, {6, 7}}), true);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3, 4, 5, 6}, {7}}), true);
+TEST (1, [d(2)][d(3)], Init ({{1, 2, 3, 4, 5, 6, 7}}), true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+TEST (1, [d(1)][d(MAX)], Init (), false);
+TEST (1, [d(1)][d(MAX)], Init ({}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4, 5}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4, 5, 6}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4, 5, 6, 7}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4, 5, 6, 7, 8}}), false);
+TEST (1, [d(1)][d(MAX)], Init ({{1, 2, 3, 4, 5, 6, 7, 8, 9}}), false);
+
+TEST (1, [d(2)][d(MAX / 2)], Init (), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4, 5}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4, 5, 6}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4, 5, 6, 7}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4, 5, 6, 7, 8}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3, 4, 5, 6, 7, 8, 9}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1}, {2}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1}, {2, 3}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2}, {3}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2}, {3, 4}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3}, {4}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3}, {4, 5}}), false);
+TEST (1, [d(2)][d(MAX / 2)], Init ({{1, 2, 3}, {4, 5, 6}}), false);
+#endif
+
+TEST (1, [d(2)][d(MAX)], Init (), true);
+TEST (1, [d(2)][d(MAX)], Init ({{1}}), true);
+TEST (1, [d(MAX)][d(MAX)], Init ({{1, 2}}), true);
+TEST (1, [d(0)][d(MAX)], Init ({{1}, {2}}), true);
+TEST (1, [d(INT_MAX)][d(MAX)], Init ({{1}, {2, 3}}), true);
+TEST (1, [d(SIZE_MAX)][d(MAX)], Init ({{1, 2}, {3, 4}, {5}}), true);
+
+// Erroneous two-dimensional VLAs with size exceeding SIZE_MAX / 2
+// (those must be rejected because no object can be bigger than that,
+// otherwise pointer arithmetic breaks).
+TEST ( 1, [2][d(SIZE_MAX/2)], Init (), true);
+TEST ( 2, [2][d(SIZE_MAX/4)], Init (), true);
+TEST ( 4, [2][d(SIZE_MAX/8)], Init (), true);
+TEST ( 8, [2][d(SIZE_MAX/16)], Init (), true);
+TEST (16, [2][d(SIZE_MAX/32)], Init (), true);
+
+TEST ( 1, [d(SIZE_MAX/2)][2], Init (), true);
+TEST ( 2, [d(SIZE_MAX/4)][2], Init (), true);
+TEST ( 4, [d(SIZE_MAX/8)][2], Init (), true);
+TEST ( 8, [d(SIZE_MAX/16)][2], Init (), true);
+TEST (16, [d(SIZE_MAX/32)][2], Init (), true);
+
+// Verify that the unspecified bound is factored into the computation
+// of the total size.
+TEST ( 1, [][d(SIZE_MAX/2)], Init ({{1}, {2}}), true);
+TEST ( 2, [][d(SIZE_MAX/4)], Init ({{1}, {2}}), true);
+TEST ( 4, [][d(SIZE_MAX/8)], Init ({{1}, {2}}), true);
+TEST ( 8, [][d(SIZE_MAX/16)], Init ({{1}, {2}}), true);
+TEST (16, [][d(SIZE_MAX/32)], Init ({{1}, {2}}), true);
+TEST (16, [][d(SIZE_MAX/64)], Init ({{1}, {2}, {3}}), true);
+
+// Three dimensional VLAs with two constant bounds.
+
+TEST (1, [1][1][d(-1)], Init (), true);
+TEST (1, [1][1][d(0)], Init (), true);
+
+#if !BUG_58646
+// The following causes an ICE due to c++/58646.
+TEST (1, [1][1][d(0)], Init ({}), true);
+TEST (1, [1][1][d(-1)], Init ({{}}), true);
+TEST (1, [1][d(-1)][1], Init ({{}}), true);
+TEST (1, [d(-1)][1][1], Init ({{}}), true);
+
+TEST (1, [1][1][d(0)], Init ({{}}), true);
+TEST (1, [1][d(0)][1], Init ({{}}), true);
+TEST (1, [d(0)][1][1], Init ({{}}), true);
+#endif
+
+TEST (1, [1][1][d(1)], Init (), false);
+
+#if !BUG_58646
+TEST (1, [1][1][d(1)], Init ({{}}), false);
+TEST (1, [1][1][d(1)], Init ({{{}}}), false);
+TEST (1, [1][1][d(1)], Init ({{{1}}}), false);
+#endif
+
+TEST (1, [1][1][d(1)], Init ({{{1, 2}}}), true);
+TEST (1, [1][1][d(1)], Init ({{{1, 2, 3}}}), true);
+
+TEST (1, [1][d(1)][1], Init (), false);
+
+#if !BUG_58646
+TEST (1, [1][d(1)][1], Init ({{}}), false);
+TEST (1, [1][d(1)][1], Init ({{{}}}), false);
+#endif
+
+TEST (1, [1][d(1)][1], Init ({{{1}}}), false);
+TEST (1, [1][d(1)][1], Init ({{{1}, {2}}}), true);
+TEST (1, [1][d(1)][1], Init ({{{1}, {2}, {3}}}), true);
+
+TEST (1, [d(1)][1][1], Init (), false);
+
+#if !BUG_58646
+TEST (1, [d(1)][1][1], Init ({{}}), false);
+TEST (1, [d(1)][1][1], Init ({{{}}}), false);
+#endif
+
+TEST (1, [d(1)][1][1], Init ({{{1}}}), false);
+TEST (1, [d(1)][1][1], Init ({{{1}}, {{2}}}), true);
+TEST (1, [d(1)][1][1], Init ({{{1}}, {{2}}, {{3}}}), true);
+
+TEST (1, [1][1][d(2)], Init (), false);
+
+#if !BUG_58646
+TEST (1, [1][1][d(2)], Init ({{}}), false);
+TEST (1, [1][1][d(2)], Init ({{{}}}), false);
+#endif
+
+TEST (1, [1][1][d(2)], Init ({{{1}}}), false);
+TEST (1, [1][1][d(2)], Init ({{{1, 2}}}), false);
+TEST (1, [1][1][d(2)], Init ({{{1, 2, 3}}}), true);
+
+TEST (1, [1][d(2)][1], Init (), false);
+
+#if !BUG_58646
+TEST (1, [1][d(2)][1], Init ({{}}), false);
+TEST (1, [1][d(2)][1], Init ({{{}}}), false);
+#endif
+TEST (1, [1][d(2)][1], Init ({{{1}}}), false);
+TEST (1, [1][d(2)][1], Init ({{{1}, {2}}}), false);
+TEST (1, [1][d(2)][1], Init ({{{1}, {2}, {3}}}), true);
+
+TEST (1, [d(2)][1][1], Init (), false);
+
+#if !BUG_58646
+TEST (1, [d(2)][1][1], Init ({{}}), false);
+TEST (1, [d(2)][1][1], Init ({{{}}}), false);
+#endif
+TEST (1, [d(2)][1][1], Init ({{{1}}}), false);
+TEST (1, [d(2)][1][1], Init ({{{1}}, {{2}}}), false);
+TEST (1, [d(2)][1][1], Init ({{{1}}, {{2}}, {{3}}}), true);
+
+TEST (1, [1][2][d(2)], Init (), false);
+
+#if !BUG_58646
+TEST (1, [1][2][d(2)], Init ({{}}), false);
+TEST (1, [1][2][d(2)], Init ({{{}}}), false);
+#endif
+
+TEST (1, [1][2][d(2)], Init ({{{1}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1, 2}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3}}}), true);
+
+TEST (1, [1][2][d(2)], Init ({{{1}, {2}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1}, {2, 3}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1, 2}, {3}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1, 2}, {3, 4}}}), false);
+TEST (1, [1][2][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3}, {}}}), true);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3}, {4}}}), true);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3, 4}}}), true);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3, 4}, {}}}), true);
+TEST (1, [1][2][d(2)], Init ({{{1, 2, 3, 4}, {5}}}), true);
+
+TEST (1, [2][2][d(2)], Init ({{{1}, {2}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1}, {2, 3}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7}}}), false);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}), false);
+
+TEST (1, [2][2][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3}, {}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3}, {4}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3, 4}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3, 4}, {}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3, 4}, {5}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7, 8, 9}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6, 7}, {8, 9}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2}, {3, 4, 5}}, {{6, 7}, {8, 9}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1, 2, 3}, {4, 5}}, {{6, 7}, {8, 9}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1}, {2}}, {{3}, {4, 5, 6}}}), true);
+TEST (1, [2][2][d(2)], Init ({{{1}}, {{2}, {3, 4, 5, 6}}}), true);
+
+// Three dimensional VLAs with one constant bound.
+TEST (1, [2][d(-1)][d(-1)], Init (), true);
+TEST (1, [2][d(-1)][d(0)], Init (), true);
+TEST (1, [2][d(0)][d(-1)], Init (), true);
+TEST (1, [2][d(1)][d(-1)], Init (), true);
+TEST (1, [2][d(1)][d(0)], Init (), true);
+TEST (1, [2][d(-1)][d(1)], Init (), true);
+TEST (1, [2][d(0)][d(1)], Init (), true);
+
+TEST (1, [2][d(2)][d(2)], Init (), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1}, {2}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1}, {2, 3}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2}, {3}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}), false);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}), false);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3}, {}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2, 3}, {}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3}, {4}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2, 3}, {4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2, 3, 4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {5}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {5}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [ ][d(2)][d(2)], Init ({{{1}, {2, 3, 4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3}, {4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3}, {}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3}, {4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3, 4}, {5}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6}, {7, 8, 9}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3, 4}}, {{5, 6, 7}, {8, 9}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2}, {3, 4, 5}}, {{6, 7}, {8, 9}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1, 2, 3}, {4, 5}}, {{6, 7}, {8, 9}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2}}, {{3}, {4, 5, 6}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}}, {{2}, {3, 4, 5, 6}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2}, {3}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3}, {4}}}), true);
+TEST (1, [2][d(2)][d(2)], Init ({{{1}, {2, 3, 4}, {5}}}), true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+// Very large but not erroneous three-dimensional VLAs.
+TEST ( 1, [2][d(1)][d(MAX/2)], Init (), false);
+TEST ( 2, [2][d(1)][d(MAX/4)], Init (), false);
+TEST ( 4, [2][d(1)][d(MAX/8)], Init (), false);
+TEST ( 8, [2][d(1)][d(MAX/16)], Init (), false);
+TEST (16, [2][d(1)][d(MAX/32)], Init (), false);
+
+TEST ( 1, [2][d(MAX/2)][d(1)], Init (), false);
+TEST ( 2, [2][d(MAX/4)][d(1)], Init (), false);
+TEST ( 4, [2][d(MAX/8)][d(1)], Init (), false);
+TEST ( 8, [2][d(MAX/16)][d(1)], Init (), false);
+TEST (16, [2][d(MAX/32)][d(1)], Init (), false);
+
+TEST ( 1, [d(MAX/2)][2][d(1)], Init (), false);
+TEST ( 2, [d(MAX/4)][2][d(1)], Init (), false);
+TEST ( 4, [d(MAX/8)][2][d(1)], Init (), false);
+TEST ( 8, [d(MAX/16)][2][d(1)], Init (), false);
+TEST (16, [d(MAX/32)][2][d(1)], Init (), false);
+#endif // TEST_NEAR_VLA_MAX_SIZE
+
+// Erroneous three-dimensional VLAs with size exceeding SIZE_MAX / 2
+// (those must be rejected because no object can be bigger than that,
+// otherwise pointer arithmetic breaks).
+TEST ( 1, [2][d(1)][d(SIZE_MAX/2)], Init (), true);
+TEST ( 2, [2][d(1)][d(SIZE_MAX/4)], Init (), true);
+TEST ( 4, [2][d(1)][d(SIZE_MAX/8)], Init (), true);
+TEST ( 8, [2][d(1)][d(SIZE_MAX/16)], Init (), true);
+TEST (16, [2][d(1)][d(SIZE_MAX/32)], Init (), true);
+
+TEST ( 1, [2][d(SIZE_MAX/2)][d(1)], Init (), true);
+TEST ( 2, [2][d(SIZE_MAX/4)][d(1)], Init (), true);
+TEST ( 4, [2][d(SIZE_MAX/8)][d(1)], Init (), true);
+TEST ( 8, [2][d(SIZE_MAX/16)][d(1)], Init (), true);
+TEST (16, [2][d(SIZE_MAX/32)][d(1)], Init (), true);
+
+TEST ( 1, [d(SIZE_MAX/2)][2][d(1)], Init (), true);
+TEST ( 2, [d(SIZE_MAX/4)][2][d(1)], Init (), true);
+TEST ( 4, [d(SIZE_MAX/8)][2][d(1)], Init (), true);
+TEST ( 8, [d(SIZE_MAX/16)][2][d(1)], Init (), true);
+TEST (16, [d(SIZE_MAX/32)][2][d(1)], Init (), true);
+
+TEST (16, [3][d(SIZE_MAX)][d(SIZE_MAX)], Init (), true);
+TEST (32, [d(SIZE_MAX)][5][d(SIZE_MAX)], Init (), true);
+TEST (64, [d(SIZE_MAX)][d(SIZE_MAX)][7], Init (), true);
+
+int main ()
+{
+ if (fail)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/vla12.C b/gcc/testsuite/g++.dg/cpp1y/vla12.C
new file mode 100644
index 0000000..a8db578
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/vla12.C
@@ -0,0 +1,69 @@
+// Test to verify that variable length arrays whose size overflows
+// or exceeds the implementation-defined limit is diagnosed.
+// { dg-do run { target c++11 } }
+// { dg-additional-options "-Wno-error=vla" }
+
+#define INT_MAX __INT_MAX__
+#define LONG_MAX __LONG_MAX__
+#define SIZE_MAX __SIZE_MAX__
+
+typedef __SIZE_TYPE__ size_t;
+
+void test (int x, int y, int z)
+{
+ const size_t amax = SIZE_MAX / 2;
+
+ {
+ char a [x][amax]; // { dg-warning "forbids|size of variable length array exceeds maximum" }
+ (void)a;
+ }
+
+ {
+ char a [amax][y]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ char a [x][y][amax]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ char a [x][amax][z]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ char a [amax][y][z]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ // Unfortunately, this is rejected with a different error earlier
+ // during parsing and before the VLA checking gets to see it:
+ // error: size of array âaâ is too large
+ char a [x][amax][amax]; // { dg-error "size of array" }
+
+ // That error above also leads to the following error when using
+ // the variable below.
+ // error:â was not declared in this scope
+ // (void)a;
+ }
+
+ {
+ char a [amax][y][amax]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ char a [amax][amax][z]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+
+ {
+ struct A256 { __attribute__ ((aligned (256))) char a; };
+
+ A256 a [x][1024][y][1024][z][1024][x][1024][z]; // { dg-warning "forbids|size of variable length array" }
+ (void)a;
+ }
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/vla13.C b/gcc/testsuite/g++.dg/cpp1y/vla13.C
new file mode 100644
index 0000000..7ddf893
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/vla13.C
@@ -0,0 +1,250 @@
+// PR c++/70019 - VLA size overflow not detected
+// Runtime test to verify that attempting to initialize a VLA with a string
+// or character array that's longer than the non-constant (runtime) bound
+// of the VLA causes an exception to be thrown. For a compile-time version
+// of the test see vla14.C.
+
+// { dg-do run { target c++11 } }
+// { dg-additional-options "-Wno-vla" }
+
+#pragma GCC diagnostic ignored "-Wvla"
+
+#define SIZE_MAX __SIZE_MAX__
+
+// The size of the largest allowed VLA in bytes. Bigger objects
+// cause an exception to be thrown. Unless the maximum size is
+// obscenely large, smaller objects should be successfully created
+// provided there's enough stack space. See TEST_NEAR_VLA_MAX_SIZE
+// below.
+#define MAX (__SIZE_MAX__ / 2)
+
+// Define to non-zero to exercise very large VLAs with size just
+// below the implementation-defined maximum.
+#define TEST_NEAR_VLA_MAX_SIZE 0
+
+// Define to zero to enable tests that cause an ICE due to c++/58646.
+#define BUG_58646 1
+
+// Define to zero to enable tests that cause an ICE due to c++/69487.
+#define BUG_69487 1
+
+// Helper macro to make it possible to pass as one multpile arguments
+// to another macro.
+#define Init(...) __VA_ARGS__
+
+typedef __SIZE_TYPE__ size_t;
+
+// Incremented for each test failure.
+int fail;
+
+// Used to convert a constant array dimension to a non-constant one.
+template <class T>
+T d (T n)
+{
+ return n;
+}
+
+// Verify either that an expected exception has been thrown or that
+// one hasn't been thrown if one isn't expected.
+int __attribute__ ((noclone, noinline))
+sink (void *p, int line, bool expect, const char *expr)
+{
+ if (!p != expect)
+ {
+ __builtin_printf ("line %i: Assertion failed: '%s': "
+ "exception unexpectedly %sthrown\n",
+ line, expr, !p ? "" : "not ");
+ ++fail;
+ }
+ else
+ {
+#if defined DEBUG && DEBUG
+ __builtin_printf ("line %i: Assertion passed: '%s': "
+ "exception %sthrown as expected\n",
+ line, expr, !p ? "" : "not ");
+#endif
+ }
+ return 0;
+}
+
+template <class T, int>
+int test ();
+
+#define _CAT(name, line) name ## line
+#define CAT(name, line) _CAT (name, line)
+
+#define STR(...) #__VA_ARGS__
+
+// Macro to define a unique specialization of a function template to
+// exercise a VLA of type T, rank N, with dimensions given by Dims
+// and initializer Init. Expect is true when the VLA initialization
+// is expected to trigger an exception.
+// The macro creates a unique global dummy int object and initializes
+// it with the result of the function. The dummy object servers no
+// other purpose but to call the function. The function verifies
+// the expected postconditions.
+#define TEST(T, Dims, Init, Expect) \
+ template <> \
+ int test<T, __LINE__>() \
+ { \
+ const char str[] = "char a" #Dims " = { " STR (Init) " }"; \
+ try { \
+ T a Dims = { Init }; \
+ return sink (a, __LINE__, Expect, str); \
+ } \
+ catch (...) { \
+ return sink (0, __LINE__, Expect, str); \
+ } \
+ } \
+ const int CAT (dummy, __LINE__) = test<T, __LINE__>()
+
+
+// Create and run a test function exercising a VLA definition
+// +-- Element Type
+// | +-- VLA Dimensions
+// | | +-- VLA Initializer
+// | | |
+// | | | +-- Expect Exception
+// | | | |
+// V V V V
+TEST (char, [d(-1)], "", true);
+TEST (char, [d(0)], "", true);
+TEST (char, [d(1)], "", false);
+TEST (char, [d(1)], "1", true);
+TEST (char, [d(1)], "12", true);
+TEST (char, [d(1)], "1234567890", true);
+
+TEST (char, [d(2)], "", false);
+TEST (char, [d(2)], "1", false);
+TEST (char, [d(2)], "12", true);
+TEST (char, [d(2)], "123", true);
+TEST (char, [d(2)], "1234567890", true);
+
+TEST (char, [d(3)], "", false);
+TEST (char, [d(3)], "1", false);
+TEST (char, [d(3)], "12", false);
+TEST (char, [d(3)], "123", true);
+TEST (char, [d(3)], "1234", true);
+TEST (char, [d(3)], "1234567890", true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+
+# if !BUG_69487
+// The following crash due to c++/69487.
+TEST (char, [d(MAX)], "", false);
+TEST (char, [d(MAX)], "1", false);
+TEST (char, [d(MAX)], "12", false);
+TEST (char, [d(MAX)], "1234567890", false);
+# endif
+
+TEST (char, [d(MAX)], Init (), false);
+TEST (char, [d(MAX)], Init (1), false);
+TEST (char, [d(MAX)], Init (1, 2), false);
+TEST (char, [d(MAX)], Init (1, 2, 3, 4, 5, 6, 7, 8, 9, 0), false);
+#endif
+
+TEST (char, [d(SIZE_MAX / 2 + 1)], "", true);
+TEST (char, [d(SIZE_MAX - 2)], "", true);
+TEST (char, [d(SIZE_MAX - 1)], "", true);
+
+TEST (wchar_t, [d(1)], L"", false);
+TEST (wchar_t, [d(1)], L"1", true);
+TEST (wchar_t, [d(1)], L"12", true);
+TEST (wchar_t, [d(1)], L"1234567890", true);
+
+TEST (wchar_t, [d(2)], L"", false);
+TEST (wchar_t, [d(2)], L"1", false);
+TEST (wchar_t, [d(2)], L"12", true);
+TEST (wchar_t, [d(2)], L"123", true);
+TEST (wchar_t, [d(2)], L"1234567890", true);
+
+TEST (char, [d(1)][d(1)], Init (""), false);
+TEST (char, [1] [d(1)], Init (""), false);
+TEST (char, [d(1)][1], Init (""), false);
+
+TEST (char, [d(1)][d(1)], Init ("1"), true);
+
+// The following is accepted at compile time but throws an exception
+// at runtime since in C++ a one-element array cannot be initialized
+// with a string literal of length one because there isn't room for
+// the terminating NUL
+TEST (char, [1][d(1)], Init ("1"), true);
+
+// The following is rejected at compile-time since a one-element array
+// cannot be initialized with a string literal of length one because
+// there isn't room for the terminating NUL (see vla14.C).
+// TEST (char, [d(1)][1], Init ("1"), false);
+
+TEST (char, [d(1)][d(1)], Init ("12"), true);
+TEST (char, [d(1)][d(1)], Init ("1", "2"), true);
+TEST (char, [d(1)][d(1)], Init ("1", "23"), true);
+
+TEST (char, [d(2)][d(2)], Init ("", ""), false);
+TEST (char, [d(2)][d(2)], Init ("", "1"), false);
+TEST (char, [d(2)][d(2)], Init ("1", ""), false);
+TEST (char, [d(2)][d(2)], Init ("1", "1"), false);
+TEST (char, [2][d(2)], Init ("", "1"), false);
+TEST (char, [2][d(2)], Init ("1", ""), false);
+TEST (char, [2][d(2)], Init ("1", "1"), false);
+TEST (char, [d(2)][2], Init ("", "1"), false);
+TEST (char, [d(2)][2], Init ("1", ""), false);
+TEST (char, [d(2)][2], Init ("1", "1"), false);
+
+TEST (char, [2][d(2)], Init ("1", "23"), true);
+TEST (char, [d(2)][d(2)], Init ("1", "23"), true);
+TEST (char, [d(2)][d(2)], Init ("1", "23"), true);
+TEST (char, [d(2)][d(2)], Init ("12","3"), true);
+
+#if TEST_NEAR_VLA_MAX_SIZE
+# if !BUG_69487
+ // The following crash due to c++/69487.
+TEST (char, [1][d(MAX)], Init (""), false);
+TEST (char, [1][d(MAX)], Init ("1"), false);
+TEST (char, [1][d(MAX)], Init ("12"), false);
+TEST (char, [1][d(MAX)], Init ("1234567890"), false);
+# endif
+
+# if !BUG_58646
+// The following causes an ICE due to c++/58646.
+TEST (char, [1][d(MAX)], Init (), false);
+# endif
+
+TEST (char, [1][d(MAX)], Init ({1}), false);
+TEST (char, [1][d(MAX)], Init ({1, 2}), false);
+TEST (char, [1][d(MAX)], Init ({1, 2, 3}), false);
+TEST (char, [1][d(MAX)], Init ({1, 2, 3, 4, 5, 6, 7, 8, 9, 0}), false);
+
+TEST (char, [d(MAX)][1], Init ({1}), false);
+TEST (char, [d(MAX)][1], Init ({1}, {2}), false);
+TEST (char, [d(MAX)][1], Init ({1}, {2}, {3}), false);
+TEST (char, [d(MAX)][1], Init ({1}, {2}, {3}, {4}, {5},
+ {6}, {7}, {8}, {9}, {0}), false);
+#endif // TEST_NEAR_VLA_MAX_SIZE
+
+// The following are expected to throw due to excessive size.
+TEST (char, [2][d(MAX)], Init ({1}), true);
+TEST (char, [2][d(MAX)], Init ({1, 2}), true);
+TEST (char, [2][d(MAX)], Init ({1}, {2}), true);
+TEST (char, [2][d(MAX)], Init ({1, 2}, {3, 4}), true);
+TEST (char, [2][d(MAX)], Init ({1, 2, 3}, {4, 5, 6}), true);
+TEST (char, [2][d(MAX)], Init ({1, 2, 3, 4}, {5, 6, 7, 8}), true);
+
+TEST (char, [d(MAX)][2], Init ({1}), true);
+TEST (char, [d(MAX)][2], Init ({1, 2}), true);
+TEST (char, [d(MAX)][2], Init ({1}, {2}), true);
+TEST (char, [d(MAX)][2], Init ({1, 2}, {3, 4}), true);
+TEST (char, [d(MAX)][2], Init ({1, 2}, {3, 4}, {5, 6}), true);
+TEST (char, [d(MAX)][2], Init ({1, 2}, {3, 4}, {5, 6}, {7, 8}), true);
+
+TEST (char, [d(MAX)][d(MAX)], Init ({1}), true);
+TEST (char, [d(MAX)][d(MAX)], Init ({1, 2}), true);
+TEST (char, [d(MAX)][d(MAX)], Init ({1}, {2}), true);
+TEST (char, [d(MAX)][d(MAX)], Init ({1, 2}, {3, 4}), true);
+TEST (char, [d(MAX)][d(MAX)], Init ({1, 2}, {3, 4}, {5, 6}), true);
+TEST (char, [d(MAX)][d(MAX)], Init ({1, 2}, {3, 4}, {5, 6}, {7, 8}), true);
+
+int main ()
+{
+ if (fail)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/vla14.C b/gcc/testsuite/g++.dg/cpp1y/vla14.C
new file mode 100644
index 0000000..4a0e827
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/vla14.C
@@ -0,0 +1,48 @@
+// PR c++/70019 - VLA size overflow not detected
+// Compile-time test to verify that attempting to initialize a VLA with
+// a string that's longer than the VLA's constant bound is diagnosed at
+// compile time. For a runtime version of the test see vla13.C.
+
+// { dg-do run }
+// { dg-additional-options "-Wno-vla" }
+
+
+void test (int n)
+{
+ char a1[n][1] = { { "a" } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a1;
+
+ char a2[1][n] = { { "a" } };
+ (void)a2;
+
+ char a3[n][1][1] = { { { "a" } } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a3;
+
+ char a4[1][1][n] = { { { "a" } } };
+ (void)a4;
+
+ char a5[1][n][1] = { { { "a" } } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a5;
+
+ char a6[n][1][n] = { { { "a" } } };
+ (void)a6;
+
+
+ wchar_t a7[n][1] = { { L"a" } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a7;
+
+ wchar_t a8[1][n] = { { L"a" } };
+ (void)a8;
+
+ wchar_t a9[n][1][1] = { { { L"a" } } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a9;
+
+ wchar_t a10[1][1][n] = { { { L"a" } } };
+ (void)a10;
+
+ wchar_t a11[][n][1] = { { { L"a" } } }; // { dg-error "initializer-string for array of chars is too long" }
+ (void)a11;
+
+ wchar_t a12[n][1][n] = { { { L"a" } } };
+ (void)a12;
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/vla3.C b/gcc/testsuite/g++.dg/cpp1y/vla3.C
new file mode 100644
index 0000000..9b2d6b3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/vla3.C
@@ -0,0 +1,43 @@
+// Test for throwing bad_array_length on invalid array length.
+// { dg-do run { target c++14 } }
+// { dg-additional-options "-Wno-vla" }
+
+namespace std
+{
+struct exception
+{
+ virtual ~exception ();
+ virtual const char* what () const throw ();
+};
+}
+
+int f(int i)
+{
+ int ar[i]{1,2,3,4};
+ return ar[i-1];
+}
+
+void g(int i)
+{
+ int ar[i];
+ ar[0] = 42;
+}
+
+int main()
+{
+ int ok = 0;
+ f(4); // OK
+ try {
+ f(3); // too small
+ }
+ catch (std::exception &e) {
+ ++ok;
+ }
+ try { g(-24); } // negative
+ catch (std::exception &e) {
+ ++ok;
+ }
+
+ if (ok != 2)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/init/array24.C b/gcc/testsuite/g++.dg/init/array24.C
index 2d72df4..fc10c0a 100644
--- a/gcc/testsuite/g++.dg/init/array24.C
+++ b/gcc/testsuite/g++.dg/init/array24.C
@@ -3,5 +3,5 @@
void foo(int i)
{
- int x[][i] = { 0 };
+ int x[][i] = { { 0 } };
}
diff --git a/gcc/testsuite/g++.dg/ubsan/vla-1.C b/gcc/testsuite/g++.dg/ubsan/vla-1.C
index 311cdb1..374c80a 100644
--- a/gcc/testsuite/g++.dg/ubsan/vla-1.C
+++ b/gcc/testsuite/g++.dg/ubsan/vla-1.C
@@ -1,5 +1,8 @@
// { dg-do run }
-// { dg-options "-Wno-vla -fsanitize=undefined" }
+// Disable exceptions to prevent the erroneous initializer from
+// throwing before the sanitizer instrumentation has detected
+// the problem.
+// { dg-options "-Wno-vla -fno-exceptions -fsanitize=undefined" }
// { dg-output "index 1 out of bounds" }
void f(int i) {
diff --git a/libstdc++-v3/testsuite/25_algorithms/rotate/moveable2.cc b/libstdc++-v3/testsuite/25_algorithms/rotate/moveable2.cc
index d9d1f2a..f944236 100644
--- a/libstdc++-v3/testsuite/25_algorithms/rotate/moveable2.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/rotate/moveable2.cc
@@ -44,7 +44,8 @@ template<typename Con>
{
bool test __attribute__((unused)) = true;
- rvalstruct array[length];
+ /* Make sure the VLA upper bound is positive. */
+ rvalstruct array[length + 1];
for(int i = 0; i < length; ++i)
array[i] = i;
Con con(array, array + length);
PR c++/69517 - [5/6 regression] SEGV on a VLA with excess initializer elements
PR c++/70019 - VLA size overflow not detected
gcc/cp/ChangeLog:
2016-04-10 Martin Sebor <mse...@redhat.com>
PR c++/69517
PR c++/70019
* cp-tree.h (throw_bad_array_length, build_vla_check): Declare new
functions.
* decl.c (check_initializer, cp_finish_decl): Call them.
(reshape_init_r): Reject incompletely braced intializer-lists
for VLAs.
* init.c (throw_bad_array_length, build_vla_check)
(build_vla_size_check, build_vla_init_check): Define new functions.
* typeck2.c (split_nonconstant_init_1): Use variably_modified_type_p()
to detect a VLA.
(store_init_value): Same.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index b7b770f..1d726fd 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5978,6 +5978,7 @@ extern tree build_value_init_noctor (tree, tsubst_flags_t);
extern tree get_nsdmi (tree, bool);
extern tree build_offset_ref (tree, tree, bool,
tsubst_flags_t);
+extern tree throw_bad_array_length (void);
extern tree throw_bad_array_new_length (void);
extern tree build_new (vec<tree, va_gc> **, tree, tree,
vec<tree, va_gc> **, int,
@@ -5999,6 +6000,7 @@ extern tree scalar_constant_value (tree);
extern tree decl_really_constant_value (tree);
extern int diagnose_uninitialized_cst_or_ref_member (tree, bool, bool);
extern tree build_vtbl_address (tree);
+extern tree build_vla_check (tree, tree = NULL_TREE);
/* in lex.c */
extern void cxx_dup_lang_specific_decl (tree);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 9260f4c..c5ec0da 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -5864,6 +5864,16 @@ reshape_init_r (tree type, reshape_iter *d, bool first_initializer_p,
}
}
+ if (variably_modified_type_p (type, NULL_TREE))
+ {
+ /* Require VLAs to have their initializers fully braced
+ to avoid initializing the wrong elements. */
+ if (complain & tf_error)
+ error ("missing braces around initializer for a variable length "
+ "array %qT", type);
+ return error_mark_node;
+ }
+
warning (OPT_Wmissing_braces, "missing braces around initializer for %qT",
type);
}
@@ -6167,6 +6177,34 @@ check_initializer (tree decl, tree init, int flags, vec<tree, va_gc> **cleanups)
&& PAREN_STRING_LITERAL_P (DECL_INITIAL (decl)))
warning (0, "array %qD initialized by parenthesized string literal %qE",
decl, DECL_INITIAL (decl));
+
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && variably_modified_type_p (type, NULL_TREE)
+ && !processing_template_decl)
+ {
+ /* Statically check for overflow in VLA bounds and build
+ an expression that checks at runtime whether the VLA
+ is erroneous due to invalid (runtime) bounds.
+ Another expression to check for excess initializers
+ is built in build_vec_init. */
+ tree check = build_vla_check (TREE_TYPE (decl), init);
+
+ if (flag_exceptions && current_function_decl
+ /* Avoid instrumenting constexpr functions for now.
+ Those must be checked statically, and the (non-
+ constexpr) dynamic instrumentation would cause
+ them to be rejected. See c++/70507. */
+ && !DECL_DECLARED_CONSTEXPR_P (current_function_decl))
+ {
+ /* Use the runtime check only when exceptions are enabled.
+ Otherwise let bad things happen... */
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
+ }
+
init = NULL;
}
}
@@ -6809,6 +6847,36 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
cleanups = make_tree_vector ();
init = check_initializer (decl, init, flags, &cleanups);
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && variably_modified_type_p (type, NULL_TREE)
+ && !processing_template_decl
+ && !init)
+ {
+ /* Statically check for overflow in VLA bounds and build
+ an expression that checks whether the VLA is erroneous
+ at runtime. A runtime check for the bounds of
+ initialized VLAs along with excess initializer
+ elements is built in build_vec_init(). */
+ tree check = build_vla_check (type);
+
+ if (flag_exceptions
+ && current_function_decl
+ /* Avoid instrumenting constexpr functions. Those must
+ be checked statically for now since the (non-constexpr)
+ dynamic instrumentation would cause them to be rejected
+ due to c++/70507. */
+ && !DECL_DECLARED_CONSTEXPR_P (current_function_decl))
+ {
+ /* Use the runtime check only when exceptions are enabled.
+ Otherwise let bad things happen (though perhaps emitting
+ a trap would be appropriate). */
+ check = build3 (COND_EXPR, void_type_node, check,
+ throw_bad_array_length (), void_node);
+
+ finish_expr_stmt (check);
+ }
+ }
+
/* Handle:
[dcl.init]
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 5997d53..ec19d72 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2262,6 +2262,20 @@ diagnose_uninitialized_cst_or_ref_member (tree type, bool using_new, bool compla
return diagnose_uninitialized_cst_or_ref_member_1 (type, type, using_new, complain);
}
+/* Call __cxa_throw_bad_array_length to indicate that the size calculation
+ in the bounds of a variable length array overflowed. */
+
+tree
+throw_bad_array_length (void)
+{
+ tree fn = get_identifier ("__cxa_throw_bad_array_length");
+ if (!get_global_value_if_present (fn, &fn))
+ fn = push_throw_library_fn (fn, build_function_type_list (void_type_node,
+ NULL_TREE));
+
+ return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
+}
+
/* Call __cxa_bad_array_new_length to indicate that the size calculation
overflowed. Pretend it returns sizetype so that it plays nicely in the
COND_EXPR. */
@@ -4709,3 +4723,304 @@ build_vec_delete (tree base, tree maxindex,
return rval;
}
+
+
+/* The implementation of build_vla_check() that recursively builds
+ an expression to determine whether the VLA TYPE is erroneous due
+ either to its bounds being invalid or to integer overflow in
+ the computation of its total size.
+ CHECK is the boolean expression being built, initialized to
+ boolean_false_node.
+ VLASIZE is used internally to pass the incrementally computed
+ size of the VLA object down to its recursive invocations.
+ MAX_VLASIZE is the maximum valid size of the VLA in bytes.
+ CST_SIZE is the product of the VLA's constant dimensions. */
+
+static tree
+build_vla_size_check (tree check,
+ tree type,
+ tree vlasize,
+ tree max_vlasize,
+ offset_int *cst_size)
+{
+ tree vmul = builtin_decl_explicit (BUILT_IN_MUL_OVERFLOW);
+
+ tree vlasizeaddr = build_unary_op (input_location, ADDR_EXPR, vlasize, 0);
+
+ bool overflow = false;
+
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ /* Compute the upper bound of this array type. */
+ tree inner_nelts = array_type_nelts_top (type);
+ tree inner_nelts_cst = maybe_constant_value (inner_nelts);
+
+ if (TREE_CODE (inner_nelts_cst) == INTEGER_CST)
+ {
+ /* The upper bound is a constant expression. Compute the product
+ of the constant upper bounds seen so far so that overflow can
+ be diagnosed. */
+ offset_int result = wi::mul (wi::to_offset (inner_nelts_cst),
+ *cst_size, SIGNED, &overflow);
+ *cst_size = overflow ? 0 : result;
+ }
+
+ /* Check for overflow in the VLAs (runtime) upper bounds. */
+ tree vflowcheck = build_call_expr (vmul, 3, inner_nelts,
+ vlasize, vlasizeaddr);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, vflowcheck);
+
+ /* Recursively check for overflow in the remaining major bounds. */
+ check = build_vla_size_check (check, TREE_TYPE (type),
+ vlasize, max_vlasize,
+ cst_size);
+ }
+ else
+ {
+ /* Get the size of the VLA element type in bytes. */
+ tree typesize = TYPE_SIZE_UNIT (type);
+
+ /* See if the size, when multipled by the product of the VLA's
+ constant dimensions, is within range of size_t. If not,
+ the VLA is definitely erroneous amd must be diagnosed at
+ compile time. */
+ offset_int result = wi::mul (wi::to_offset (typesize), *cst_size,
+ SIGNED, &overflow);
+ *cst_size = overflow ? 0 : result;
+
+ /* Multiply the (non-constant) VLA size so far by the element size,
+ checking for overflow, and replacing the value of vlasize with
+ the product in the absence of overflow. This size is the total
+ runtime size of the VLA in bytes. */
+ tree vflowcheck = build_call_expr (vmul, 3, typesize,
+ vlasize, vlasizeaddr);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, vflowcheck);
+
+ /* Check to see if the final VLA size exceeds the maximum. */
+ tree sizecheck = fold_build2 (LT_EXPR, boolean_type_node,
+ max_vlasize, vlasize);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, sizecheck);
+
+ /* Also check to see if the final array size is zero (the size
+ is unsigned so the earlier overflow check detects negative
+ values as well. */
+ tree zerocheck = fold_build2 (EQ_EXPR, boolean_type_node,
+ vlasize, size_zero_node);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, zerocheck);
+ }
+
+ /* Diagnose overflow determined at compile time. */
+ if (overflow)
+ {
+ error ("integer overflow in variable array size");
+ /* Reset to suppress any further diagnostics. */
+ *cst_size = 0;
+ }
+
+ return check;
+}
+
+/* The implementation of build_vla_check() that recursively builds
+ an expression to determine whether the VLA initializer-list for
+ TYPE is erroneous due to excess initializers.
+ CHECK is the boolean expression being built, initialized to
+ the result of build_vla_size_check().
+ INIT is the VLA initializer expression to check against TYPE.
+ On the first (non-recursive) call, INIT_ELTS is set either to 1,
+ or to the number of elements in the initializer-list for VLAs
+ of unspecified (major) bound. On subsequent (recursive) calls.
+ it is set to NULL and computed from the number of elements in
+ the (nested) initializer-list.
+*/
+
+static tree
+build_vla_init_check (tree check, tree type, tree init, tree init_elts)
+{
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ /* Compute the upper bound of this array type unless it has
+ already been computed by the caller for an array of unspecified
+ bound, as in 'T a[];' */
+ tree inner_nelts = init_elts ? init_elts : array_type_nelts_top (type);
+
+ size_t len;
+
+ if (TREE_CODE (init) == CONSTRUCTOR)
+ {
+ /* The initializer of this array is itself an array. Build
+ an expression to check if the number of elements in the
+ initializer array exceeds the upper bound of the type
+ of the object being initialized. */
+ if (vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (init))
+ {
+ len = v->length ();
+ tree initelts = build_int_cstu (size_type_node, len);
+ tree initcheck = fold_build2 (LT_EXPR, boolean_type_node,
+ inner_nelts, initelts);
+
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, initcheck);
+
+ constructor_elt *ce;
+ HOST_WIDE_INT i;
+
+ /* Iterate over all non-empty initializers in this array,
+ recursively building expressions to see if the elements
+ of each are in excess of the corresponding (runtime)
+ bound of the array type. */
+ FOR_EACH_VEC_SAFE_ELT (v, i, ce)
+ check = build_vla_init_check (check, TREE_TYPE (type),
+ ce->value, NULL_TREE);
+ }
+ }
+ else if (TREE_CODE (init) == STRING_CST
+ && (len = TREE_STRING_LENGTH (init)))
+ {
+ /* The initializer of this array is a string. */
+ tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (init)));
+ len /= TYPE_PRECISION (ctype) / BITS_PER_UNIT;
+
+ /* A C++ string literal initializer must have at most as many
+ characters as there are elements in the array, including
+ the terminating NUL. */
+ tree initelts = build_int_cstu (size_type_node, len);
+ tree initcheck = fold_build2 (LT_EXPR, boolean_type_node,
+ inner_nelts, initelts);
+ check = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+ check, initcheck);
+ }
+ else if (TREE_CODE (init) == ERROR_MARK)
+ {
+ // No checking is possible.
+ check = boolean_false_node;
+ }
+ else
+ {
+ /* What's this array initializer? */
+ gcc_unreachable ();
+ }
+ }
+
+ return check;
+}
+
+/* Build an expression to determine whether the VLA TYPE is erroneous.
+ INIT is the VLA initializer expression or NULL_TREE when the VLA is
+ not initialized. */
+
+tree
+build_vla_check (tree type, tree init /* = NULL_TREE */)
+{
+ tree check = boolean_false_node;
+
+ /* The product of all constant dimensions of the VLA, initialized
+ to either 1 in the common case or to the number of elements in
+ the VLA's initializer-list for VLAs of unspecified (major)
+ bound. */
+ offset_int cst_size = 1;
+
+ /* The initial size of the VLA to start the computation of the total
+ size with. Like CST_SIZE above, initialized to 1 or the number
+ of elements in the VLA's initializer-list for VLAs of unspecified
+ bound. */
+ tree initial_size = size_one_node;
+
+ /* For a VLA of unspecified (major) bound, the number of elements
+ it is initialized with determined from the initializer-list. */
+ tree initial_elts = NULL_TREE;
+
+ if (init)
+ {
+ /* Determine the upper bound of the VLA of unspecified bound,
+ as in 'T a[];' if this is such a VLA. Such a VLA can be
+ initialized with any number of elements but the number of
+ elements so determined must be used to check the total size
+ of the VLA. */
+ gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
+
+ if (tree dom = TYPE_DOMAIN (type))
+ if (tree max = TYPE_MAX_VALUE (dom))
+ if (integer_zerop (max))
+ {
+ if (TREE_CODE (init) == CONSTRUCTOR)
+ {
+ vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (init);
+
+ /* Since the upper bound of every array must be positive
+ a VLA with an unspecified major bound must be initized
+ by a non-empty initializer list. */
+ gcc_assert (v != NULL);
+
+ cst_size = v->length ();
+ }
+ else if (TREE_CODE (init) == STRING_CST)
+ {
+ /* The initializer is a (possibly empty) string consisting
+ at a minumum of one character, the terminating NUL.
+ This condition implies a definition like
+ char s [][N] = "";
+ which is an error but even though it has been diagnosed
+ by this point the initializer still winds up here. */
+ size_t nchars = TREE_STRING_LENGTH (init);
+ tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (init)));
+ nchars /= TYPE_PRECISION (ctype) / BITS_PER_UNIT;
+
+ cst_size = nchars + 1;
+ }
+
+ initial_elts = wide_int_to_tree (size_type_node, cst_size);
+ initial_size = initial_elts;
+ }
+ }
+
+ /* Build a variable storing the total runtime size of the VLA and
+ initialize it either to 1 (in the common case) or to the number
+ of topmost elements in the initializer-list when the VLA is
+ an array of unspecified (major) bound. */
+ tree vlasize = build_decl (input_location,
+ VAR_DECL, NULL_TREE, sizetype);
+ DECL_ARTIFICIAL (vlasize) = 1;
+ DECL_IGNORED_P (vlasize) = 1;
+ DECL_CONTEXT (vlasize) = current_function_decl;
+ DECL_INITIAL (vlasize) = initial_size;
+ vlasize = pushdecl (vlasize);
+ add_decl_expr (vlasize);
+
+ /* Impose a lenient limit on the size of the biggest VLA in bytes.
+ FIXME: Tighten up the limit to make it more useful and make it
+ configurable for users with unusual requirements. */
+ tree max_vlasize
+ = fold_build2 (RSHIFT_EXPR, size_type_node,
+ build_all_ones_cst (size_type_node),
+ integer_one_node);
+
+ /* Build an expression that checks the runtime bounds of the VLA
+ for invalid values and the total size of the VLA for overflow. */
+ check = build_vla_size_check (check, type, vlasize, max_vlasize, &cst_size);
+
+ if (wi::ltu_p (wi::to_offset (max_vlasize), cst_size))
+ {
+ /* Issue the warning only in the "topmost" (non-recursive) call
+ to avoid duplicating diagnostics. This is only a warning to
+ allow programs to be portable to more permissive environments. */
+ warning (OPT_Wvla, "size of variable length array exceeds maximum "
+ "of %qE bytes", max_vlasize);
+ }
+
+ if (init)
+ {
+ /* Build an expression that checks the VLA initializer expression
+ against the type of the VLA for excess elements. */
+ check = build_vla_init_check (check, type, init, initial_elts);
+ }
+
+ return check;
+}
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index b921689..eba19ca 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -603,7 +603,7 @@ split_nonconstant_init_1 (tree dest, tree init)
array_type_p = true;
if ((TREE_SIDE_EFFECTS (init)
&& TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
- || array_of_runtime_bound_p (type))
+ || variably_modified_type_p (type, NULL_TREE))
{
/* For an array, we only need/want a single cleanup region rather
than one per element. */
@@ -845,7 +845,7 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
will perform the dynamic initialization. */
if (value != error_mark_node
&& (TREE_SIDE_EFFECTS (value)
- || array_of_runtime_bound_p (type)
+ || variably_modified_type_p (type, NULL_TREE)
|| ! reduced_constant_expression_p (value)))
return split_nonconstant_init (decl, value);
/* If the value is a constant, just put it in DECL_INITIAL. If DECL
