/* Return variable availability. See cgraph.h for description of individual
return values. */
enum availability
cgraph_variable_initializer_availability (varpool_node *node)
{
if (!node->definition)
return AVAIL_NOT_AVAILABLE;
if (!TREE_PUBLIC (node->decl))
return AVAIL_AVAILABLE;
if (DECL_IN_CONSTANT_POOL (node->decl)
|| DECL_VIRTUAL_P (node->decl))
return AVAIL_AVAILABLE;
if (node->alias && node->weakref)
{
enum availability avail;
cgraph_variable_initializer_availability
(varpool_variable_node (node, &avail));
return avail;
}
/* If the variable can be overwritten, return OVERWRITABLE. Takes
care of at least one notable extension - the COMDAT variables
used to share template instantiations in C++. */
if (decl_replaceable_p (node->decl)
|| DECL_EXTERNAL (node->decl))
return AVAIL_OVERWRITABLE;
return AVAIL_AVAILABLE;
}
/* Return variable availability. See cgraph.h for description of individual
return values. */
enum availability
cgraph_variable_initializer_availability (struct varpool_node *node)
{
gcc_assert (cgraph_function_flags_ready);
if (!node->finalized)
return AVAIL_NOT_AVAILABLE;
if (!TREE_PUBLIC (node->decl))
return AVAIL_AVAILABLE;
/* If the variable can be overwritten, return OVERWRITABLE. Takes
care of at least two notable extensions - the COMDAT variables
used to share template instantiations in C++. */
if (!decl_replaceable_p (node->decl))
return AVAIL_OVERWRITABLE;
return AVAIL_AVAILABLE;
}
bool
const_value_known_p (tree decl)
{
if (TREE_CODE (decl) != VAR_DECL
&&TREE_CODE (decl) != CONST_DECL)
return false;
if (TREE_CODE (decl) == CONST_DECL
|| DECL_IN_CONSTANT_POOL (decl))
return true;
gcc_assert (TREE_CODE (decl) == VAR_DECL);
if (!TREE_READONLY (decl) || TREE_THIS_VOLATILE (decl))
return false;
/* Gimplifier takes away constructors of local vars */
if (!TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
return DECL_INITIAL (decl) != NULL;
gcc_assert (TREE_STATIC (decl) || DECL_EXTERNAL (decl));
/* Variables declared 'const' without an initializer
have zero as the initializer if they may not be
overridden at link or run time. */
if (!DECL_INITIAL (decl)
&& (DECL_EXTERNAL (decl)
|| decl_replaceable_p (decl)))
return false;
/* Variables declared `const' with an initializer are considered
to not be overwritable with different initializer by default.
??? Previously we behaved so for scalar variables but not for array
accesses. */
return true;
}
tree
ctor_for_folding (tree decl)
{
varpool_node *node, *real_node;
tree real_decl;
if (TREE_CODE (decl) != VAR_DECL
&& TREE_CODE (decl) != CONST_DECL)
return error_mark_node;
if (TREE_CODE (decl) == CONST_DECL
|| DECL_IN_CONSTANT_POOL (decl))
return DECL_INITIAL (decl);
if (TREE_THIS_VOLATILE (decl))
return error_mark_node;
/* Do not care about automatic variables. Those are never initialized
anyway, because gimplifier exapnds the code. */
if (!TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
{
gcc_assert (!TREE_PUBLIC (decl));
return error_mark_node;
}
gcc_assert (TREE_CODE (decl) == VAR_DECL);
node = varpool_get_node (decl);
if (node)
{
real_node = varpool_variable_node (node);
real_decl = real_node->decl;
}
else
real_decl = decl;
/* See if we are dealing with alias.
In most cases alias is just alternative symbol pointing to a given
constructor. This allows us to use interposition rules of DECL
constructor of REAL_NODE. However weakrefs are special by being just
alternative name of their target (if defined). */
if (decl != real_decl)
{
gcc_assert (!DECL_INITIAL (decl)
|| DECL_INITIAL (decl) == error_mark_node);
if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
{
node = varpool_alias_target (node);
decl = node->decl;
}
}
/* Vtables are defined by their types and must match no matter of interposition
rules. */
if (DECL_VIRTUAL_P (real_decl))
{
gcc_checking_assert (TREE_READONLY (real_decl));
return DECL_INITIAL (real_decl);
}
/* If there is no constructor, we have nothing to do. */
if (DECL_INITIAL (real_decl) == error_mark_node)
return error_mark_node;
/* Non-readonly alias of readonly variable is also de-facto readonly,
because the variable itself is in readonly section.
We also honnor READONLY flag on alias assuming that user knows
what he is doing. */
if (!TREE_READONLY (decl) && !TREE_READONLY (real_decl))
return error_mark_node;
/* Variables declared 'const' without an initializer
have zero as the initializer if they may not be
overridden at link or run time. */
if (!DECL_INITIAL (real_decl)
&& (DECL_EXTERNAL (decl) || decl_replaceable_p (decl)))
return error_mark_node;
/* Variables declared `const' with an initializer are considered
to not be overwritable with different initializer by default.
??? Previously we behaved so for scalar variables but not for array
accesses. */
return DECL_INITIAL (real_decl);
}
