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glr2.cc: add sanity checks in glr_stack_item

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We obviously have broken pointer arithmetics that hands us
glr_stack_items that are not glr_stack_items.  Have a simple check for
this, to have earlier failures.

* data/skeletons/glr2.cc (glr_stack_item::check_): New.
Use it.
(glr_stack_item::contents): Avoid the useless struct.
Fix minor stylistic issues.
This commit is contained in:
Akim Demaille
2020-12-06 16:21:29 +01:00
parent 42fe808292
commit 2313f891bd
1 changed files with 46 additions and 23 deletions
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69
data/skeletons/glr2.cc
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@@ -1155,7 +1155,8 @@ class glr_stack_item
{
public:
glr_stack_item (bool state = true)
: is_state_ (state)
: is_state_ (state)]b4_parse_assert_if([[
, magic_ (MAGIC)]])[
{
if (is_state_)
new (&raw_) glr_state;
@@ -1163,21 +1164,26 @@ public:
new (&raw_) semantic_option;
}
glr_stack_item(const glr_stack_item& other) YY_NOEXCEPT YY_NOTHROW
: is_state_(other.is_state_)
{
std::memcpy(raw_, other.raw_, union_size);
glr_stack_item (const glr_stack_item& other) YY_NOEXCEPT YY_NOTHROW
: is_state_ (other.is_state_)]b4_parse_assert_if([[
, magic_ (0xDEAD1ACC)]])[
{]b4_parse_assert_if([[
other.check_ ();]])[
std::memcpy (raw_, other.raw_, union_size);
}
glr_stack_item& operator=(glr_stack_item other)
{
std::swap(is_state_, other.is_state_);
std::swap(raw_, other.raw_);
glr_stack_item& operator= (glr_stack_item other)
{]b4_parse_assert_if([[
check_ ();
other.check_ ();]])[
std::swap (is_state_, other.is_state_);
std::swap (raw_, other.raw_);
return *this;
}
~glr_stack_item()
{
~glr_stack_item ()
{]b4_parse_assert_if([[
check_ ();]])[
if (is_state())
getState().~glr_state();
else
@@ -1185,44 +1191,48 @@ public:
}
glr_state& getState ()
{
{]b4_parse_assert_if([[
check_ ();]])[
YYDASSERT (is_state ());
void *yyp = raw_;
return *static_cast<glr_state*> (yyp);
}
const glr_state& getState () const
{
YYDASSERT (is_state());
{]b4_parse_assert_if([[
check_ ();]])[
YYDASSERT (is_state ());
const void *yyp = raw_;
return *static_cast<const glr_state*> (yyp);
}
semantic_option& getOption ()
{
{]b4_parse_assert_if([[
check_ ();]])[
YYDASSERT (!is_state ());
void *yyp = raw_;
return *static_cast<semantic_option*> (yyp);
}
const semantic_option& getOption () const
{
{]b4_parse_assert_if([[
check_ ();]])[
YYDASSERT (!is_state ());
const void *yyp = raw_;
return *static_cast<const semantic_option*> (yyp);
}
bool is_state () const
{
{]b4_parse_assert_if([[
check_ ();]])[
return is_state_;
}
private:
/// The possible contents of raw_. Since they have constructors, they cannot
/// be directly included in the union.
struct contents {
union {
char yystate[sizeof(glr_state)];
char yyoption[sizeof(semantic_option)];
};
union contents
{
char yystate[sizeof (glr_state)];
char yyoption[sizeof (semantic_option)];
};
enum { union_size = sizeof(contents) };
enum { union_size = sizeof (contents) };
union {
/// Strongest alignment constraints.
long double yyalign_me;
@@ -1231,6 +1241,17 @@ public:
};
/** Type tag for the union. */
bool is_state_;
]b4_parse_assert_if([[
// Check invariants.
void check_ () const
{
YYASSERT (this->magic_ == MAGIC);
YYASSERT (this->is_state_ == false || this->is_state_ == true);
}
// A magic number to check our pointer arithmetics is sane.
enum { MAGIC = 0xDEAD1ACC };
const unsigned int magic_;]])[
};
glr_state* glr_state::pred ()
@@ -1272,7 +1293,9 @@ std::ptrdiff_t semantic_option::indexIn(glr_stack_item* array) {
}
glr_state* semantic_option::state() {
YY_IGNORE_NULL_DEREFERENCE_BEGIN
return yystate ? &(asItem(this) - yystate)->getState() : YY_NULLPTR;
YY_IGNORE_NULL_DEREFERENCE_END
}
const glr_state* semantic_option::state() const {