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This PR should be the base for discussion, do not merge it yet!

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It correctly detects reg/wire mix and incorrect use on blocking,nonblocking assignments within blocks and assign statements.

What it DOES'T do:
Detect registers connected to output ports of instances.

Where it FAILS:
memorty nonblocking assignments causes spurious (I assume??) errors on yosys-generated "_ADDR", "_DATA", "EN" signals.

You can test it with tests/simple/reg_wire_error.v (look inside for the comments to enable/disable specific lines)
This commit is contained in:
Udi Finkelstein 2018-03-09 10:35:33 +02:00
parent efaef82f75
commit 2b9c75f8e3
6 changed files with 63 additions and 4 deletions
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10
frontends/ast/simplify.cc
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@ -327,6 +327,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
if (node->type == AST_WIRE) {
if (this_wire_scope.count(node->str) > 0) {
AstNode *first_node = this_wire_scope[node->str];
if (first_node->is_input && node->is_reg)
goto wires_are_incompatible;
if (!node->is_input && !node->is_output && node->is_reg && node->children.size() == 0)
goto wires_are_compatible;
if (first_node->children.size() == 0 && node->children.size() == 1 && node->children[0]->type == AST_RANGE) {
@ -361,6 +363,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
first_node->is_output = true;
if (node->is_reg)
first_node->is_reg = true;
if (node->is_logic)
first_node->is_logic = true;
if (node->is_signed)
first_node->is_signed = true;
for (auto &it : node->attributes) {
@ -440,6 +444,12 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
children[1]->detectSignWidth(width_hint, sign_hint);
width_hint = max(width_hint, backup_width_hint);
child_0_is_self_determined = true;
if ((type == AST_ASSIGN_LE || type == AST_ASSIGN_EQ) && children[0]->id2ast->is_logic)
children[0]->id2ast->is_reg = true; // if logic type is used in a block asignment
if ((type == AST_ASSIGN_LE || type == AST_ASSIGN_EQ) && !children[0]->id2ast->is_reg)
log_warning("wire '%s' is assigned in a block at %s:%d.\n", children[0]->str.c_str(), filename.c_str(), linenum);
if (type == AST_ASSIGN && children[0]->id2ast->is_reg)
log_error("reg '%s' is assigned in a continuous assignment at %s:%d.\n", children[0]->str.c_str(), filename.c_str(), linenum);
break;
case AST_PARAMETER: