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Find implicit nets in expressions passed to ports. 

It is questionable, but probably legal, for expressions passed as
arguments to input ports of various kinds of gates to implicitly
declare nets. This patch allows the scan through different types
of expressions for implicit nets.

The elaborate_sig handling here does not test for the legality of
having a non-trivial expression as argument to a port. For example,
it is definitely NOT legal to have r-value expressions passed to
output or inout ports. But that will be checked for later when the
instance is elaborated for real.
This commit is contained in:
Stephen Williams 2008-03-23 17:52:48 -07:00
parent 140fd45460
commit 14e3a886bd
2 changed files with 28 additions and 0 deletions
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6
PExpr.h
View File

@ -474,6 +474,8 @@ class PEUnary : public PExpr {
virtual void dump(ostream&out) const;
virtual bool elaborate_sig(Design*des, NetScope*scope) const;
virtual NetNet* elaborate_net(Design*des, NetScope*scope,
unsigned width,
const NetExpr* rise,
@ -533,6 +535,8 @@ class PEBinary : public PExpr {
unsigned min, unsigned lval,
bool&unsized_flag) const;
virtual bool elaborate_sig(Design*des, NetScope*scope) const;
virtual NetNet* elaborate_net(Design*des, NetScope*scope,
unsigned width,
const NetExpr* rise,
@ -648,6 +652,8 @@ class PETernary : public PExpr {
unsigned min, unsigned lval,
bool&unsized_flag) const;
virtual bool elaborate_sig(Design*des, NetScope*scope) const;
virtual NetNet* elaborate_net(Design*des, NetScope*scope,
unsigned width,
const NetExpr* rise,

22
elab_sig.cc
View File

@ -267,6 +267,28 @@ bool PEIdent::elaborate_sig(Design*des, NetScope*scope) const
return sig != 0;
}
bool PEBinary::elaborate_sig(Design*des, NetScope*scope) const
{
bool flag = true;
flag = left_->elaborate_sig(des, scope) && flag;
flag = right_->elaborate_sig(des, scope) && flag;
return flag;
}
bool PETernary::elaborate_sig(Design*des, NetScope*scope) const
{
bool flag = true;
flag = tru_->elaborate_sig(des, scope) && flag;
flag = fal_->elaborate_sig(des, scope) && flag;
return flag;
}
bool PEUnary::elaborate_sig(Design*des, NetScope*scope) const
{
return expr_->elaborate_sig(des, scope);
}
bool PGate::elaborate_sig(Design*des, NetScope*scope) const
{
return true;