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Handle context signedness and width expansion for method return types 

The signedness of an expression can change depending on its context. E.g.
for an arithmetic operation with one unsigned operand all operands are
treated as unsigned.

For methods, both on built-in SystemVerilog types as well as user defined
classes, this is currently not considered. This can lead to incorrect behavior
if the value is sign extended.

E.g. the following will print 4294967295 rather than 65535.

```
shortint q[$];
q.push_back(-1);
$display(q.pop_front() + 32'h0);
```

Furthermore the return value is not expanded to the width of its context.
This can cause vvp to crash with an exception when it expects a vector on
the stack to have a certain width.

E.g.
```
int d[];
longint x;
bit a = 1'b1;
x = a ? d.size() : 64'h0;
```

Solve both of this by using `pad_to_width()` on the method return value if
it is a vectorable type. Since any function call, not just methods, needs
to have this done to its return value insert this on the common path.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This commit is contained in:
Lars-Peter Clausen 2022-04-11 10:38:00 +02:00
parent 2f38adaeff
commit 22cba1073c
4 changed files with 60 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
PExpr.h
View File

@ -926,22 +926,25 @@ class PECallFunction : public PExpr {
NetExpr* cast_to_width_(NetExpr*expr, unsigned wid) const;
NetExpr* elaborate_expr_(Design *des, NetScope *scope,
unsigned flags) const;
NetExpr*elaborate_expr_pkg_(Design*des, NetScope*scope,
unsigned expr_wid, unsigned flags)const;
unsigned flags)const;
NetExpr* elaborate_expr_method_(Design*des, NetScope*scope,
symbol_search_results&search_results,
unsigned expr_wid) const;
symbol_search_results&search_results)
const;
NetExpr* elaborate_expr_method_par_(Design*des, NetScope*scope,
symbol_search_results&search_results,
unsigned expr_wid) const;
symbol_search_results&search_results)
const;
NetExpr* elaborate_sfunc_(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
NetExpr* elaborate_access_func_(Design*des, NetScope*scope, ivl_nature_t,
unsigned expr_wid) const;
NetExpr* elaborate_access_func_(Design*des, NetScope*scope, ivl_nature_t)
const;
unsigned test_width_sfunc_(Design*des, NetScope*scope,
width_mode_t&mode);
unsigned test_width_method_(Design*des, NetScope*scope,
@ -949,7 +952,7 @@ class PECallFunction : public PExpr {
width_mode_t&mode);
NetExpr*elaborate_base_(Design*des, NetScope*scope, NetScope*dscope,
unsigned expr_wid, unsigned flags) const;
unsigned flags) const;
unsigned elaborate_arguments_(Design*des, NetScope*scope,
NetFuncDef*def, bool need_const,

88
elab_expr.cc
View File

@ -1873,8 +1873,7 @@ NetExpr* PECallFunction::elaborate_sfunc_(Design*des, NetScope*scope,
}
NetExpr* PECallFunction::elaborate_access_func_(Design*des, NetScope*scope,
ivl_nature_t nature,
unsigned expr_wid) const
ivl_nature_t nature) const
{
// An access function must have 1 or 2 arguments.
ivl_assert(*this, parms_.size()==2 || parms_.size()==1);
@ -1925,8 +1924,7 @@ NetExpr* PECallFunction::elaborate_access_func_(Design*des, NetScope*scope,
NetExpr*tmp = new NetEAccess(branch, nature);
tmp->set_line(*this);
return pad_to_width(tmp, expr_wid, signed_flag_, *this);
return tmp;
}
/*
@ -1938,7 +1936,6 @@ static NetExpr* check_for_enum_methods(const LineInfo*li,
const pform_name_t&use_path,
perm_string method_name,
NetExpr*expr,
unsigned rtn_wid,
PExpr*parg, unsigned args)
{
if (debug_elaborate) {
@ -1948,8 +1945,6 @@ static NetExpr* check_for_enum_methods(const LineInfo*li,
<< endl;
cerr << li->get_fileline() << ": " << __func__ << ": "
<< "use_path=" << use_path << endl;
cerr << li->get_fileline() << ": " << __func__ << ": "
<< "rtn_wid=" << rtn_wid << endl;
cerr << li->get_fileline() << ": " << __func__ << ": "
<< "expr=" << *expr << endl;
}
@ -2569,7 +2564,6 @@ NetExpr* PEIdent::elaborate_expr_class_field_(Design*des, NetScope*scope,
}
NetExpr* PECallFunction::elaborate_expr_pkg_(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const
{
if (debug_elaborate) {
@ -2594,7 +2588,7 @@ NetExpr* PECallFunction::elaborate_expr_pkg_(Design*des, NetScope*scope,
if (! check_call_matches_definition_(des, dscope))
return 0;
return elaborate_base_(des, scope, dscope, expr_wid, flags);
return elaborate_base_(des, scope, dscope, flags);
}
NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
@ -2611,14 +2605,24 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
<< " at " << package_->get_fileline() << endl;
}
if (package_)
return elaborate_expr_pkg_(des, scope, expr_wid, flags);
flags &= ~SYS_TASK_ARG; // don't propagate the SYS_TASK_ARG flag
if (peek_tail_name(path_)[0] == '$')
return elaborate_sfunc_(des, scope, expr_wid, flags);
NetExpr *result = elaborate_expr_(des, scope, flags);
if (!result || !type_is_vectorable(expr_type_))
return result;
return pad_to_width(result, expr_wid, signed_flag_, *this);
}
NetExpr* PECallFunction::elaborate_expr_(Design*des, NetScope*scope,
unsigned flags) const
{
if (package_)
return elaborate_expr_pkg_(des, scope, flags);
flags &= ~SYS_TASK_ARG; // don't propagate the SYS_TASK_ARG flag
// Search for the symbol. This should turn up a scope.
symbol_search_results search_results;
bool search_flag = symbol_search(this, des, scope, path_, &search_results);
@ -2655,7 +2659,7 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
// Maybe this is a method of an object? Give it a try.
if (!search_results.path_tail.empty()) {
NetExpr*tmp = elaborate_expr_method_(des, scope, search_results, expr_wid);
NetExpr*tmp = elaborate_expr_method_(des, scope, search_results);
if (tmp) {
if (debug_elaborate) {
cerr << get_fileline() << ": PECallFunction::elaborate_expr: "
@ -2688,8 +2692,7 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
// way.
ivl_nature_t access_nature = find_access_function(path_);
if (access_nature)
return elaborate_access_func_(des, scope, access_nature,
expr_wid);
return elaborate_access_func_(des, scope, access_nature);
// Nothing was found so report this as an error.
cerr << get_fileline() << ": error: No function named `" << path_
@ -2726,8 +2729,7 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
use_search_results.net = scope->find_signal(perm_string::literal(THIS_TOKEN));
ivl_assert(*this, use_search_results.net);
NetExpr*tmp = elaborate_expr_method_(des, scope, use_search_results, expr_wid);
return tmp;
return elaborate_expr_method_(des, scope, use_search_results);
}
}
@ -2753,7 +2755,7 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
scope->is_const_func(false);
}
return elaborate_base_(des, scope, dscope, expr_wid, flags);
return elaborate_base_(des, scope, dscope, flags);
}
NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
@ -2766,7 +2768,7 @@ NetExpr* PECallFunction::elaborate_expr(Design*des, NetScope*scope,
}
NetExpr* PECallFunction::elaborate_base_(Design*des, NetScope*scope, NetScope*dscope,
unsigned expr_wid, unsigned flags) const
unsigned flags) const
{
if (! check_call_matches_definition_(des, dscope))
@ -2845,11 +2847,7 @@ NetExpr* PECallFunction::elaborate_base_(Design*des, NetScope*scope, NetScope*ds
NetESignal*eres = new NetESignal(res);
NetEUFunc*func = new NetEUFunc(scope, dscope, eres, parms, need_const);
func->set_line(*this);
if(res->darray_type())
return func;
return pad_to_width(func, expr_wid, signed_flag_, *this);
return func;
}
cerr << get_fileline() << ": internal error: Unable to locate "
@ -2960,8 +2958,8 @@ unsigned PECallFunction::elaborate_arguments_(Design*des, NetScope*scope,
* "len" in path_tail, and if x is a string object, we can handle the case.
*/
NetExpr* PECallFunction::elaborate_expr_method_(Design*des, NetScope*scope,
symbol_search_results&search_results,
unsigned expr_wid) const
symbol_search_results&search_results)
const
{
if (!gn_system_verilog()) {
cerr << get_fileline() << ": error: "
@ -3000,7 +2998,7 @@ NetExpr* PECallFunction::elaborate_expr_method_(Design*des, NetScope*scope,
}
if (search_results.par_val && search_results.par_type) {
return elaborate_expr_method_par_(des, scope, search_results, expr_wid);
return elaborate_expr_method_par_(des, scope, search_results);
}
NetExpr* sub_expr = 0;
@ -3135,8 +3133,7 @@ NetExpr* PECallFunction::elaborate_expr_method_(Design*des, NetScope*scope,
return check_for_enum_methods(this, des, scope,
netenum, path_,
method_name, sub_expr,
expr_wid, tmp,
parms_.size());
tmp, parms_.size());
}
// Class methods. Generate function call to the class method.
@ -3250,8 +3247,8 @@ NetExpr* PECallFunction::elaborate_expr_method_(Design*des, NetScope*scope,
* stable in the sense that they generate a constant value for a constant input.
*/
NetExpr* PECallFunction::elaborate_expr_method_par_(Design*des, NetScope*scope,
symbol_search_results&search_results,
unsigned expr_wid) const
symbol_search_results&search_results)
const
{
ivl_assert(*this, search_results.par_val);
ivl_assert(*this, search_results.par_type);
@ -3273,13 +3270,13 @@ NetExpr* PECallFunction::elaborate_expr_method_par_(Design*des, NetScope*scope,
if (method_name=="len") {
NetEConst*use_val = make_const_val(par_value.size());
use_val->set_line(*this);
return pad_to_width(use_val, expr_wid, *this);
return use_val;
}
if (method_name == "atoi") {
NetEConst*use_val = make_const_val(atoi(par_value.c_str()));
use_val->set_line(*this);
return pad_to_width(use_val, expr_wid, true, *this);
return use_val;
}
if (method_name == "atoreal") {
@ -3291,7 +3288,7 @@ NetExpr* PECallFunction::elaborate_expr_method_par_(Design*des, NetScope*scope,
if (method_name == "atohex") {
NetEConst*use_val = make_const_val(strtoul(par_value.c_str(),0,16));
use_val->set_line(*this);
return pad_to_width(use_val, expr_wid, true, *this);
return use_val;
}
// Returning 0 here will cause the caller to print an error
@ -4677,7 +4674,9 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
arg->set_line(*sr.net);
fun->parm(0, arg);
return fun;
if (!fun)
return 0;
return pad_to_width(fun, expr_wid, signed_flag_, *this);
} else if (member_comp.name == "find") {
cerr << get_fileline() << ": sorry: 'find()' "
"array location method is not currently "
@ -4796,7 +4795,9 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
arg->set_line(*sr.net);
fun->parm(0, arg);
return fun;
if (!fun || !type_is_vectorable(expr_type_))
return fun;
return pad_to_width(fun, expr_wid, signed_flag_, *this);
}
if (member_comp.name == "pop_front") {
@ -4808,7 +4809,9 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
arg->set_line(*sr.net);
fun->parm(0, arg);
return fun;
if (!fun || !type_is_vectorable(expr_type_))
return fun;
return pad_to_width(fun, expr_wid, signed_flag_, *this);
}
}
@ -4858,10 +4861,13 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
ivl_assert(*this, sr.path_tail.size() == 1);
const name_component_t member_comp = sr.path_tail.front();
ivl_assert(*this, member_comp.index.empty());
return check_for_enum_methods(this, des, use_scope,
NetExpr *tmp = check_for_enum_methods(this, des, use_scope,
netenum, sr.path_head,
member_comp.name,
expr, expr_wid, NULL, 0);
expr, NULL, 0);
if (!tmp)
return 0;
return pad_to_width(tmp, expr_wid, signed_flag_, *this);
}
ivl_assert(*this, sr.path_tail.empty());

1
net_expr.cc
View File

@ -561,6 +561,7 @@ ivl_variable_type_t NetEShallowCopy::expr_type() const
NetEAccess::NetEAccess(NetBranch*br, ivl_nature_t nat)
: branch_(br), nature_(nat)
{
cast_signed_base_(true);
}
NetEAccess::~NetEAccess()

1
netlist.cc
View File

@ -2159,6 +2159,7 @@ NetEUFunc::NetEUFunc(NetScope*scope, NetScope*def, NetESignal*res,
: scope_(scope), func_(def), result_sig_(res), parms_(p), need_const_(nc)
{
expr_width(result_sig_->expr_width());
cast_signed_base_(result_sig_->has_sign());
}
NetEUFunc::~NetEUFunc()