token_id cap_single(ast_t* type)
{
size_t i;
switch(ast_id(type))
{
case TK_NOMINAL:
i = 3;
break;
case TK_TYPEPARAMREF:
i = 1;
break;
default:
assert(0);
return TK_NONE;
}
ast_t* cap = ast_childidx(type, i);
ast_t* eph = ast_sibling(cap);
token_id tcap = ast_id(cap);
token_id teph = ast_id(eph);
cap_aliasing(&tcap, &teph);
return tcap;
}
token_id cap_single(ast_t* type)
{
ast_t* cap = cap_fetch(type);
ast_t* eph = ast_sibling(cap);
token_id tcap = ast_id(cap);
token_id teph = ast_id(eph);
cap_aliasing(&tcap, &teph);
return tcap;
}
bool cap_view_lower(token_id left_cap, token_id left_eph,
token_id* right_cap, token_id* right_eph)
{
left_cap = cap_unbind(left_cap);
*right_cap = cap_unbind(*right_cap);
cap_aliasing(&left_cap, &left_eph);
cap_aliasing(right_cap, right_eph);
// Can't see through these viewpoints.
switch(left_cap)
{
case TK_TAG:
case TK_CAP_SEND:
case TK_CAP_SHARE:
case TK_CAP_ANY:
return false;
default: {}
}
// A tag is always seen as a tag.
if(*right_cap == TK_TAG)
return true;
switch(left_cap)
{
case TK_ISO:
{
switch(*right_cap)
{
case TK_ISO:
case TK_CAP_SEND:
if(left_eph == TK_EPHEMERAL)
*right_eph = TK_EPHEMERAL;
break;
case TK_VAL:
case TK_CAP_SHARE:
break;
case TK_CAP_READ:
case TK_CAP_ANY:
*right_cap = TK_CAP_SEND;
if(left_eph == TK_EPHEMERAL)
*right_eph = TK_EPHEMERAL;
break;
default:
*right_cap = TK_TAG;
*right_eph = TK_NONE;
}
break;
}
case TK_TRN:
{
switch(*right_cap)
{
case TK_ISO:
case TK_TRN:
case TK_CAP_SEND:
if(left_eph == TK_EPHEMERAL)
*right_eph = TK_EPHEMERAL;
break;
case TK_VAL:
case TK_CAP_SHARE:
break;
case TK_CAP_READ:
*right_cap = TK_VAL;
*right_eph = TK_NONE;
break;
case TK_CAP_ANY:
*right_cap = TK_ISO;
if(left_eph == TK_EPHEMERAL)
*right_eph = TK_EPHEMERAL;
break;
default:
*right_cap = TK_BOX;
*right_eph = TK_NONE;
}
break;
}
case TK_REF:
break;
case TK_VAL:
{
switch(*right_cap)
{
case TK_CAP_SEND:
case TK_CAP_SHARE:
case TK_CAP_ANY:
*right_cap = TK_CAP_SHARE;
break;
default:
*right_cap = TK_VAL;
}
*right_eph = TK_NONE;
break;
}
case TK_BOX:
{
switch(*right_cap)
{
case TK_ISO:
*right_cap = TK_TAG;
break;
case TK_VAL:
case TK_CAP_SHARE:
break;
case TK_CAP_SEND:
*right_cap = TK_CAP_SHARE;
break;
case TK_CAP_READ:
case TK_CAP_ANY:
*right_cap = TK_VAL;
break;
default:
*right_cap = TK_BOX;
}
*right_eph = TK_NONE;
break;
}
case TK_CAP_READ:
{
switch(*right_cap)
{
case TK_ISO:
*right_cap = TK_CAP_SEND;
break;
case TK_REF:
*right_cap = TK_CAP_READ;
break;
case TK_BOX:
*right_cap = TK_VAL;
break;
default: {}
}
break;
}
default:
assert(0);
return false;
}
return true;
}
bool is_cap_sub_cap(token_id sub, token_id subalias, token_id super,
token_id supalias)
{
// Transform the cap based on the aliasing info.
cap_aliasing(&sub, &subalias);
cap_aliasing(&super, &supalias);
if(supalias == TK_EPHEMERAL)
{
// Sub must be ephemeral.
if(subalias != TK_EPHEMERAL)
return false;
}
if((sub == super) || (super == TK_TAG) || (super == TK_CAP_ANY_BIND))
return true;
// Every possible value of sub must be a subtype of every possible value of
// super.
switch(sub)
{
case TK_ISO:
switch(super)
{
case TK_ISO:
case TK_TRN:
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
case TK_ISO_BIND:
case TK_CAP_SEND_BIND:
return true;
default: {}
}
break;
case TK_TRN:
switch(super)
{
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_TRN_BIND:
return true;
default: {}
}
break;
case TK_REF:
switch(super)
{
case TK_BOX:
case TK_REF_BIND:
case TK_CAP_READ_BIND:
return true;
default: {}
}
break;
case TK_VAL:
switch(super)
{
case TK_BOX:
case TK_CAP_SHARE:
case TK_VAL_BIND:
case TK_CAP_READ_BIND:
case TK_CAP_SEND_BIND:
case TK_CAP_SHARE_BIND:
return true;
default: {}
}
break;
case TK_BOX:
switch(super)
{
case TK_BOX_BIND:
case TK_CAP_READ_BIND:
return true;
default: {}
}
break;
case TK_TAG:
switch(super)
{
case TK_TAG_BIND:
case TK_CAP_SEND_BIND:
case TK_CAP_SHARE_BIND:
return true;
default: {}
}
break;
case TK_CAP_READ:
switch(super)
{
case TK_BOX:
case TK_CAP_READ_BIND:
return true;
default: {}
}
break;
case TK_CAP_SEND:
switch(super)
{
case TK_CAP_SEND_BIND:
return true;
default: {}
}
break;
case TK_CAP_SHARE:
switch(super)
{
case TK_CAP_SHARE_BIND:
return true;
default: {}
}
break;
default: {}
}
return false;
}
bool is_cap_compat_cap(token_id left_cap, token_id left_eph,
token_id right_cap, token_id right_eph)
{
// Transform the cap based on the aliasing info.
cap_aliasing(&left_cap, &left_eph);
cap_aliasing(&right_cap, &right_eph);
// Ignore compatibility for bind caps.
if((cap_unbind(left_cap) != left_cap) ||
(cap_unbind(right_cap) != right_cap))
return true;
if((left_cap == TK_TAG) || (right_cap == TK_TAG))
return true;
// Every possible value of left must be compatible with every possible value
// of right.
switch(left_cap)
{
case TK_ISO:
switch(right_cap)
{
case TK_ISO:
return true;
default: {}
}
break;
case TK_TRN:
switch(right_cap)
{
case TK_TRN:
case TK_BOX:
return true;
default: {}
}
break;
case TK_REF:
switch(right_cap)
{
case TK_REF:
case TK_BOX:
return true;
default: {}
}
break;
case TK_VAL:
switch(right_cap)
{
case TK_VAL:
case TK_BOX:
case TK_CAP_SHARE:
return true;
default: {}
}
break;
case TK_BOX:
switch(right_cap)
{
case TK_TRN:
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_READ:
return true;
default: {}
}
break;
case TK_CAP_READ:
switch(right_cap)
{
case TK_BOX:
return true;
default: {}
}
break;
case TK_CAP_SEND:
break;
case TK_CAP_SHARE:
switch(right_cap)
{
case TK_VAL:
case TK_BOX:
case TK_CAP_SHARE:
return true;
default: {}
}
break;
default: {}
}
return false;
}
bool is_cap_match_cap(token_id operand_cap, token_id operand_eph,
token_id pattern_cap, token_id pattern_eph)
{
// Transform the cap based on the aliasing info.
cap_aliasing(&operand_cap, &operand_eph);
cap_aliasing(&pattern_cap, &pattern_eph);
if(pattern_eph == TK_EPHEMERAL)
{
// Operand must be ephemeral.
if(operand_eph != TK_EPHEMERAL)
return false;
}
operand_cap = cap_unbind(operand_cap);
pattern_cap = cap_unbind(pattern_cap);
if((operand_cap == pattern_cap) || (pattern_cap == TK_TAG))
return true;
// Some instantiaion of the operand refcap must be a subtype of some
// instantiation of the pattern refcap.
switch(operand_cap)
{
case TK_ISO:
case TK_CAP_SEND:
case TK_CAP_ANY:
switch(pattern_cap)
{
case TK_ISO:
case TK_TRN:
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_TRN:
switch(pattern_cap)
{
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_REF:
switch(pattern_cap)
{
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_VAL:
case TK_CAP_SHARE:
switch(pattern_cap)
{
case TK_BOX:
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_BOX:
switch(pattern_cap)
{
case TK_CAP_READ:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_TAG:
switch(pattern_cap)
{
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
case TK_CAP_READ:
switch(pattern_cap)
{
case TK_REF:
case TK_VAL:
case TK_BOX:
case TK_CAP_SHARE:
case TK_CAP_SEND:
case TK_CAP_ANY:
return true;
default: {}
}
break;
default: {}
}
return false;
}
