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fix(lib): address strict aliasing violations with Array type

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Altering the `Array` type itself isn't feasible, as this causes
unacceptable breakage with existing parsers that depend on it. Instead,
pass in individual `Array` fields for to various `_array__*` functions.

Any time the `contents` of an array may be modified (`free`d, `realloc`d,
etc), return the potentially new address out by value. This prevents any
strict aliasing violations as we're no longer writing to a type-casted
pointer.

Co-authored-by: Nathaniel Wesley Filardo <nwfilardo@gmail.com>
This commit is contained in:
Will Lillis 2026-01-15 03:01:55 -05:00
parent 29281b1f93
commit 68ec70520d
2 changed files with 248 additions and 136 deletions
Download patch file Download diff file Expand all files Collapse all files

192
crates/generate/src/templates/array.h
View file

@ -52,67 +52,91 @@ extern "C" {
/// Reserve `new_capacity` elements of space in the array. If `new_capacity` is
/// less than the array's current capacity, this function has no effect.
#define array_reserve(self, new_capacity) \
_array__reserve((Array *)(self), array_elem_size(self), new_capacity)
#define array_reserve(self, new_capacity) \
((self)->contents = _array__reserve( \
(void *)(self)->contents, &(self)->capacity, \
array_elem_size(self), new_capacity) \
)
/// Free any memory allocated for this array. Note that this does not free any
/// memory allocated for the array's contents.
#define array_delete(self) _array__delete((Array *)(self))
#define array_delete(self) _array__delete((self), (void *)(self)->contents, sizeof(*self))
/// Push a new `element` onto the end of the array.
#define array_push(self, element) \
(_array__grow((Array *)(self), 1, array_elem_size(self)), \
(self)->contents[(self)->size++] = (element))
#define array_push(self, element) \
do { \
(self)->contents = _array__grow( \
(void *)(self)->contents, (self)->size, &(self)->capacity, \
1, array_elem_size(self) \
); \
(self)->contents[(self)->size++] = (element); \
} while(0)
/// Increase the array's size by `count` elements.
/// New elements are zero-initialized.
#define array_grow_by(self, count) \
do { \
if ((count) == 0) break; \
_array__grow((Array *)(self), count, array_elem_size(self)); \
#define array_grow_by(self, count) \
do { \
if ((count) == 0) break; \
(self)->contents = _array__grow( \
(self)->contents, (self)->size, &(self)->capacity, \
count, array_elem_size(self) \
); \
memset((self)->contents + (self)->size, 0, (count) * array_elem_size(self)); \
(self)->size += (count); \
(self)->size += (count); \
} while (0)
/// Append all elements from one array to the end of another.
#define array_push_all(self, other) \
#define array_push_all(self, other) \
array_extend((self), (other)->size, (other)->contents)
/// Append `count` elements to the end of the array, reading their values from the
/// `contents` pointer.
#define array_extend(self, count, contents) \
_array__splice( \
(Array *)(self), array_elem_size(self), (self)->size, \
0, count, contents \
#define array_extend(self, count, other_contents) \
(self)->contents = _array__splice( \
(void*)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), (self)->size, 0, count, other_contents \
)
/// Remove `old_count` elements from the array starting at the given `index`. At
/// the same index, insert `new_count` new elements, reading their values from the
/// `new_contents` pointer.
#define array_splice(self, _index, old_count, new_count, new_contents) \
_array__splice( \
(Array *)(self), array_elem_size(self), _index, \
old_count, new_count, new_contents \
#define array_splice(self, _index, old_count, new_count, new_contents) \
(self)->contents = _array__splice( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), _index, old_count, new_count, new_contents \
)
/// Insert one `element` into the array at the given `index`.
#define array_insert(self, _index, element) \
_array__splice((Array *)(self), array_elem_size(self), _index, 0, 1, &(element))
#define array_insert(self, _index, element) \
(self)->contents = _array__splice( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), _index, 0, 1, &(element) \
)
/// Remove one element from the array at the given `index`.
#define array_erase(self, _index) \
_array__erase((Array *)(self), array_elem_size(self), _index)
_array__erase((void *)(self)->contents, &(self)->size, array_elem_size(self), _index)
/// Pop the last element off the array, returning the element by value.
#define array_pop(self) ((self)->contents[--(self)->size])
/// Assign the contents of one array to another, reallocating if necessary.
#define array_assign(self, other) \
_array__assign((Array *)(self), (const Array *)(other), array_elem_size(self))
#define array_assign(self, other) \
(self)->contents = _array__assign( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
(const void *)(other)->contents, (other)->size, array_elem_size(self) \
)
/// Swap one array with another
#define array_swap(self, other) \
_array__swap((Array *)(self), (Array *)(other))
#define array_swap(self, other) \
do { \
struct Swap swapped_contents = _array__swap( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
(void *)(other)->contents, &(other)->size, &(other)->capacity \
); \
(self)->contents = swapped_contents.self_contents; \
(other)->contents = swapped_contents.other_contents; \
} while (0)
/// Get the size of the array contents
#define array_elem_size(self) (sizeof *(self)->contents)
@ -157,82 +181,112 @@ extern "C" {
// Private
typedef Array(void) Array;
// Pointers to individual `Array` fields (rather than the entire `Array` itself)
// are passed to the various `_array__*` functions below to address strict aliasing
// violations that arises when the _entire_ `Array` struct is passed as `Array(void)*`.
//
// The `Array` type itself was not altered as a solution in order to avoid breakage
// with existing consumers (in particular, parsers with external scanners).
/// This is not what you're looking for, see `array_delete`.
static inline void _array__delete(Array *self) {
if (self->contents) {
ts_free(self->contents);
self->contents = NULL;
self->size = 0;
self->capacity = 0;
}
static inline void _array__delete(void *self, void *contents, size_t self_size) {
if (contents) ts_free(contents);
if (self) memset(self, 0, self_size);
}
/// This is not what you're looking for, see `array_erase`.
static inline void _array__erase(Array *self, size_t element_size,
uint32_t index) {
assert(index < self->size);
char *contents = (char *)self->contents;
static inline void _array__erase(void* self_contents, uint32_t *size,
size_t element_size, uint32_t index) {
assert(index < *size);
char *contents = (char *)self_contents;
memmove(contents + index * element_size, contents + (index + 1) * element_size,
(self->size - index - 1) * element_size);
self->size--;
(*size - index - 1) * element_size);
(*size)--;
}
/// This is not what you're looking for, see `array_reserve`.
static inline void _array__reserve(Array *self, size_t element_size, uint32_t new_capacity) {
if (new_capacity > self->capacity) {
if (self->contents) {
self->contents = ts_realloc(self->contents, new_capacity * element_size);
static inline void *_array__reserve(void *contents, uint32_t *capacity,
size_t element_size, uint32_t new_capacity) {
void *new_contents = contents;
if (new_capacity > *capacity) {
if (contents) {
new_contents = ts_realloc(contents, new_capacity * element_size);
} else {
self->contents = ts_malloc(new_capacity * element_size);
new_contents = ts_malloc(new_capacity * element_size);
}
self->capacity = new_capacity;
*capacity = new_capacity;
}
return new_contents;
}
/// This is not what you're looking for, see `array_assign`.
static inline void _array__assign(Array *self, const Array *other, size_t element_size) {
_array__reserve(self, element_size, other->size);
self->size = other->size;
memcpy(self->contents, other->contents, self->size * element_size);
static inline void *_array__assign(void* self_contents, uint32_t *self_size, uint32_t *self_capacity,
const void *other_contents, uint32_t other_size, size_t element_size) {
void *new_contents = _array__reserve(self_contents, self_capacity, element_size, other_size);
*self_size = other_size;
memcpy(new_contents, other_contents, *self_size * element_size);
return new_contents;
}
struct Swap {
void *self_contents;
void *other_contents;
};
/// This is not what you're looking for, see `array_swap`.
static inline void _array__swap(Array *self, Array *other) {
Array swap = *other;
*other = *self;
*self = swap;
// static inline void _array__swap(Array *self, Array *other) {
static inline struct Swap _array__swap(void *self_contents, uint32_t *self_size, uint32_t *self_capacity,
void *other_contents, uint32_t *other_size, uint32_t *other_capacity) {
void *new_self_contents = other_contents;
uint32_t new_self_size = *other_size;
uint32_t new_self_capacity = *other_capacity;
void *new_other_contents = self_contents;
*other_size = *self_size;
*other_capacity = *self_capacity;
*self_size = new_self_size;
*self_capacity = new_self_capacity;
struct Swap out = {
.self_contents = new_self_contents,
.other_contents = new_other_contents,
};
return out;
}
/// This is not what you're looking for, see `array_push` or `array_grow_by`.
static inline void _array__grow(Array *self, uint32_t count, size_t element_size) {
uint32_t new_size = self->size + count;
if (new_size > self->capacity) {
uint32_t new_capacity = self->capacity * 2;
static inline void *_array__grow(void *contents, uint32_t size, uint32_t *capacity,
uint32_t count, size_t element_size) {
void *new_contents = contents;
uint32_t new_size = size + count;
if (new_size > *capacity) {
uint32_t new_capacity = *capacity * 2;
if (new_capacity < 8) new_capacity = 8;
if (new_capacity < new_size) new_capacity = new_size;
_array__reserve(self, element_size, new_capacity);
new_contents = _array__reserve(contents, capacity, element_size, new_capacity);
}
return new_contents;
}
/// This is not what you're looking for, see `array_splice`.
static inline void _array__splice(Array *self, size_t element_size,
static inline void *_array__splice(void *self_contents, uint32_t *size, uint32_t *capacity,
size_t element_size,
uint32_t index, uint32_t old_count,
uint32_t new_count, const void *elements) {
uint32_t new_size = self->size + new_count - old_count;
uint32_t new_size = *size + new_count - old_count;
uint32_t old_end = index + old_count;
uint32_t new_end = index + new_count;
assert(old_end <= self->size);
assert(old_end <= *size);
_array__reserve(self, element_size, new_size);
void *new_contents = _array__reserve(self_contents, capacity, element_size, new_size);
char *contents = (char *)self->contents;
if (self->size > old_end) {
char *contents = (char *)new_contents;
if (*size > old_end) {
memmove(
contents + new_end * element_size,
contents + old_end * element_size,
(self->size - old_end) * element_size
(*size - old_end) * element_size
);
}
if (new_count > 0) {
@ -250,7 +304,9 @@ static inline void _array__splice(Array *self, size_t element_size,
);
}
}
self->size += new_count - old_count;
*size += new_count - old_count;
return new_contents;
}
/// A binary search routine, based on Rust's `std::slice::binary_search_by`.

192
lib/src/array.h
View file

@ -52,67 +52,91 @@ extern "C" {
/// Reserve `new_capacity` elements of space in the array. If `new_capacity` is
/// less than the array's current capacity, this function has no effect.
#define array_reserve(self, new_capacity) \
_array__reserve((Array *)(self), array_elem_size(self), new_capacity)
#define array_reserve(self, new_capacity) \
((self)->contents = _array__reserve( \
(void *)(self)->contents, &(self)->capacity, \
array_elem_size(self), new_capacity) \
)
/// Free any memory allocated for this array. Note that this does not free any
/// memory allocated for the array's contents.
#define array_delete(self) _array__delete((Array *)(self))
#define array_delete(self) _array__delete((self), (void *)(self)->contents, sizeof(*self))
/// Push a new `element` onto the end of the array.
#define array_push(self, element) \
(_array__grow((Array *)(self), 1, array_elem_size(self)), \
(self)->contents[(self)->size++] = (element))
#define array_push(self, element) \
do { \
(self)->contents = _array__grow( \
(void *)(self)->contents, (self)->size, &(self)->capacity, \
1, array_elem_size(self) \
); \
(self)->contents[(self)->size++] = (element); \
} while(0)
/// Increase the array's size by `count` elements.
/// New elements are zero-initialized.
#define array_grow_by(self, count) \
do { \
if ((count) == 0) break; \
_array__grow((Array *)(self), count, array_elem_size(self)); \
#define array_grow_by(self, count) \
do { \
if ((count) == 0) break; \
(self)->contents = _array__grow( \
(self)->contents, (self)->size, &(self)->capacity, \
count, array_elem_size(self) \
); \
memset((self)->contents + (self)->size, 0, (count) * array_elem_size(self)); \
(self)->size += (count); \
(self)->size += (count); \
} while (0)
/// Append all elements from one array to the end of another.
#define array_push_all(self, other) \
#define array_push_all(self, other) \
array_extend((self), (other)->size, (other)->contents)
/// Append `count` elements to the end of the array, reading their values from the
/// `contents` pointer.
#define array_extend(self, count, contents) \
_array__splice( \
(Array *)(self), array_elem_size(self), (self)->size, \
0, count, contents \
#define array_extend(self, count, other_contents) \
(self)->contents = _array__splice( \
(void*)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), (self)->size, 0, count, other_contents \
)
/// Remove `old_count` elements from the array starting at the given `index`. At
/// the same index, insert `new_count` new elements, reading their values from the
/// `new_contents` pointer.
#define array_splice(self, _index, old_count, new_count, new_contents) \
_array__splice( \
(Array *)(self), array_elem_size(self), _index, \
old_count, new_count, new_contents \
#define array_splice(self, _index, old_count, new_count, new_contents) \
(self)->contents = _array__splice( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), _index, old_count, new_count, new_contents \
)
/// Insert one `element` into the array at the given `index`.
#define array_insert(self, _index, element) \
_array__splice((Array *)(self), array_elem_size(self), _index, 0, 1, &(element))
#define array_insert(self, _index, element) \
(self)->contents = _array__splice( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
array_elem_size(self), _index, 0, 1, &(element) \
)
/// Remove one element from the array at the given `index`.
#define array_erase(self, _index) \
_array__erase((Array *)(self), array_elem_size(self), _index)
_array__erase((void *)(self)->contents, &(self)->size, array_elem_size(self), _index)
/// Pop the last element off the array, returning the element by value.
#define array_pop(self) ((self)->contents[--(self)->size])
/// Assign the contents of one array to another, reallocating if necessary.
#define array_assign(self, other) \
_array__assign((Array *)(self), (const Array *)(other), array_elem_size(self))
#define array_assign(self, other) \
(self)->contents = _array__assign( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
(const void *)(other)->contents, (other)->size, array_elem_size(self) \
)
/// Swap one array with another
#define array_swap(self, other) \
_array__swap((Array *)(self), (Array *)(other))
#define array_swap(self, other) \
do { \
struct Swap swapped_contents = _array__swap( \
(void *)(self)->contents, &(self)->size, &(self)->capacity, \
(void *)(other)->contents, &(other)->size, &(other)->capacity \
); \
(self)->contents = swapped_contents.self_contents; \
(other)->contents = swapped_contents.other_contents; \
} while (0)
/// Get the size of the array contents
#define array_elem_size(self) (sizeof *(self)->contents)
@ -157,82 +181,112 @@ extern "C" {
// Private
typedef Array(void) Array;
// Pointers to individual `Array` fields (rather than the entire `Array` itself)
// are passed to the various `_array__*` functions below to address strict aliasing
// violations that arises when the _entire_ `Array` struct is passed as `Array(void)*`.
//
// The `Array` type itself was not altered as a solution in order to avoid breakage
// with existing consumers (in particular, parsers with external scanners).
/// This is not what you're looking for, see `array_delete`.
static inline void _array__delete(Array *self) {
if (self->contents) {
ts_free(self->contents);
self->contents = NULL;
self->size = 0;
self->capacity = 0;
}
static inline void _array__delete(void *self, void *contents, size_t self_size) {
if (contents) ts_free(contents);
if (self) memset(self, 0, self_size);
}
/// This is not what you're looking for, see `array_erase`.
static inline void _array__erase(Array *self, size_t element_size,
uint32_t index) {
ts_assert(index < self->size);
char *contents = (char *)self->contents;
static inline void _array__erase(void* self_contents, uint32_t *size,
size_t element_size, uint32_t index) {
ts_assert(index < *size);
char *contents = (char *)self_contents;
memmove(contents + index * element_size, contents + (index + 1) * element_size,
(self->size - index - 1) * element_size);
self->size--;
(*size - index - 1) * element_size);
(*size)--;
}
/// This is not what you're looking for, see `array_reserve`.
static inline void _array__reserve(Array *self, size_t element_size, uint32_t new_capacity) {
if (new_capacity > self->capacity) {
if (self->contents) {
self->contents = ts_realloc(self->contents, new_capacity * element_size);
static inline void *_array__reserve(void *contents, uint32_t *capacity,
size_t element_size, uint32_t new_capacity) {
void *new_contents = contents;
if (new_capacity > *capacity) {
if (contents) {
new_contents = ts_realloc(contents, new_capacity * element_size);
} else {
self->contents = ts_malloc(new_capacity * element_size);
new_contents = ts_malloc(new_capacity * element_size);
}
self->capacity = new_capacity;
*capacity = new_capacity;
}
return new_contents;
}
/// This is not what you're looking for, see `array_assign`.
static inline void _array__assign(Array *self, const Array *other, size_t element_size) {
_array__reserve(self, element_size, other->size);
self->size = other->size;
memcpy(self->contents, other->contents, self->size * element_size);
static inline void *_array__assign(void* self_contents, uint32_t *self_size, uint32_t *self_capacity,
const void *other_contents, uint32_t other_size, size_t element_size) {
void *new_contents = _array__reserve(self_contents, self_capacity, element_size, other_size);
*self_size = other_size;
memcpy(new_contents, other_contents, *self_size * element_size);
return new_contents;
}
struct Swap {
void *self_contents;
void *other_contents;
};
/// This is not what you're looking for, see `array_swap`.
static inline void _array__swap(Array *self, Array *other) {
Array swap = *other;
*other = *self;
*self = swap;
// static inline void _array__swap(Array *self, Array *other) {
static inline struct Swap _array__swap(void *self_contents, uint32_t *self_size, uint32_t *self_capacity,
void *other_contents, uint32_t *other_size, uint32_t *other_capacity) {
void *new_self_contents = other_contents;
uint32_t new_self_size = *other_size;
uint32_t new_self_capacity = *other_capacity;
void *new_other_contents = self_contents;
*other_size = *self_size;
*other_capacity = *self_capacity;
*self_size = new_self_size;
*self_capacity = new_self_capacity;
struct Swap out = {
.self_contents = new_self_contents,
.other_contents = new_other_contents,
};
return out;
}
/// This is not what you're looking for, see `array_push` or `array_grow_by`.
static inline void _array__grow(Array *self, uint32_t count, size_t element_size) {
uint32_t new_size = self->size + count;
if (new_size > self->capacity) {
uint32_t new_capacity = self->capacity * 2;
static inline void *_array__grow(void *contents, uint32_t size, uint32_t *capacity,
uint32_t count, size_t element_size) {
void *new_contents = contents;
uint32_t new_size = size + count;
if (new_size > *capacity) {
uint32_t new_capacity = *capacity * 2;
if (new_capacity < 8) new_capacity = 8;
if (new_capacity < new_size) new_capacity = new_size;
_array__reserve(self, element_size, new_capacity);
new_contents = _array__reserve(contents, capacity, element_size, new_capacity);
}
return new_contents;
}
/// This is not what you're looking for, see `array_splice`.
static inline void _array__splice(Array *self, size_t element_size,
static inline void *_array__splice(void *self_contents, uint32_t *size, uint32_t *capacity,
size_t element_size,
uint32_t index, uint32_t old_count,
uint32_t new_count, const void *elements) {
uint32_t new_size = self->size + new_count - old_count;
uint32_t new_size = *size + new_count - old_count;
uint32_t old_end = index + old_count;
uint32_t new_end = index + new_count;
ts_assert(old_end <= self->size);
ts_assert(old_end <= *size);
_array__reserve(self, element_size, new_size);
void *new_contents = _array__reserve(self_contents, capacity, element_size, new_size);
char *contents = (char *)self->contents;
if (self->size > old_end) {
char *contents = (char *)new_contents;
if (*size > old_end) {
memmove(
contents + new_end * element_size,
contents + old_end * element_size,
(self->size - old_end) * element_size
(*size - old_end) * element_size
);
}
if (new_count > 0) {
@ -250,7 +304,9 @@ static inline void _array__splice(Array *self, size_t element_size,
);
}
}
self->size += new_count - old_count;
*size += new_count - old_count;
return new_contents;
}
/// A binary search routine, based on Rust's `std::slice::binary_search_by`.