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base repository: azonenberg/yosys
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  • 5 commits
  • 2 files changed
  • 1 contributor

Commits on Aug 14, 2017

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Showing with 149 additions and 0 deletions.
  1. +1 −0 passes/opt/Makefile.inc
  2. +148 −0 passes/opt/opt_rmports.cc
1 change: 1 addition & 0 deletions passes/opt/Makefile.inc
Original file line number Diff line number Diff line change
@@ -6,6 +6,7 @@ OBJS += passes/opt/opt_reduce.o
OBJS += passes/opt/opt_rmdff.o
OBJS += passes/opt/opt_clean.o
OBJS += passes/opt/opt_expr.o
OBJS += passes/opt/opt_rmports.o

ifneq ($(SMALL),1)
OBJS += passes/opt/share.o
148 changes: 148 additions & 0 deletions passes/opt/opt_rmports.cc
Original file line number Diff line number Diff line change
@@ -0,0 +1,148 @@
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/

#include "kernel/register.h"
#include "kernel/sigtools.h"
#include "kernel/log.h"
#include <stdlib.h>
#include <stdio.h>

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

struct OptRmportsPass : public Pass {
OptRmportsPass() : Pass("opt_rmports", "remove top-level ports with no connections") { }
virtual void help()
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" opt_rmports\n");
log("\n");
log("This pass identifies ports in the top-level design which are not used or driven\n");
log("and removes them\n");
log("\n");
}

virtual void execute(std::vector<std::string> /*args*/, RTLIL::Design *design)
{
log_header(design, "Executing OPT_RMPORTS pass (remove top level ports with no connections).\n");
ProcessModule(design->top_module());
}

virtual void ProcessModule(RTLIL::Module* module)
{
log("Finding unconnected ports in module %s\n", module->name.c_str());

std::set<RTLIL::IdString> used_ports;

//See what wires are used.
//Start by checking connections between named wires
auto& conns = module->connections();
for(auto sigsig : conns)
{
auto s1 = sigsig.first;
auto s2 = sigsig.second;

int len1 = s1.size();
int len2 = s2.size();
int len = len1;
if(len2 < len1)
len = len2;

for(int i=0; i<len; i++)
{
auto w1 = s1[i].wire;
auto w2 = s2[i].wire;
if( (w1 == NULL) || (w2 == NULL) )
continue;

//log(" conn %s, %s\n", w1->name.c_str(), w2->name.c_str());

if( (w1->port_input || w1->port_output) && (used_ports.find(w1->name) == used_ports.end()) )
used_ports.emplace(w1->name);

if( (w2->port_input || w2->port_output) && (used_ports.find(w2->name) == used_ports.end()) )
used_ports.emplace(w2->name);
}
}

//Then check connections to cells
auto cells = module->cells();
for(auto cell : cells)
{
auto& cconns = cell->connections();
for(auto conn : cconns)
{
for(int i=0; i<conn.second.size(); i++)
{
auto sig = conn.second[i].wire;
if(sig == NULL)
continue;

//log(" sig %s\n", sig->name.c_str());
if( (sig->port_input || sig->port_output) && (used_ports.find(sig->name) == used_ports.end()) )
used_ports.emplace(sig->name);
}
}
}

//Now that we know what IS used, get rid of anything that isn't in that list
std::set<RTLIL::IdString> unused_ports;
for(auto port : module->ports)
{
if(used_ports.find(port) != used_ports.end())
continue;
unused_ports.emplace(port);
}

//Print the ports out as we go through them
for(auto port : unused_ports)
{
log(" removing unused top-level port %s\n", port.c_str());

//Remove from ports list
for(size_t i=0; i<module->ports.size(); i++)
{
if(module->ports[i] == port)
{
module->ports.erase(module->ports.begin() + i);
break;
}
}

//Mark the wire as no longer a port
auto wire = module->wire(port);
wire->port_input = false;
wire->port_output = false;
wire->port_id = 0;
}
log("Removed %zu unused top-level ports.\n", unused_ports.size());

//Re-number all of the wires that DO have ports still on them
for(size_t i=0; i<module->ports.size(); i++)
{
auto port = module->ports[i];
auto wire = module->wire(port);
wire->port_id = i+1;
}
}

} OptRmportsPass;

PRIVATE_NAMESPACE_END