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symbol_search(): Add lookup flags 

`symbol_search()` currently uses a boolean argument to allow forward
references to the terminal name. Additional lookup options would require more
boolean arguments and make call sites difficult to read.

Replace the boolean with a bitmask and use a named flag at the existing
forward-reference call sites. Add a second flag that stops lookup at an
unelaborated signal instead of elaborating it. Stopping the lookup makes the
signal continue to hide matching symbols in outer scopes.

Forward-reference permission applies only to the terminal name, while signal
elaboration suppression applies to the complete path. This allows callers
that only need to classify a name to avoid triggering signal elaboration
during lookup.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This commit is contained in:
Lars-Peter Clausen 2026-08-16 14:46:36 -07:00
parent 9a2106a439
commit a7e258fad1
4 changed files with 43 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
elab_expr.cc
View File

@ -310,7 +310,8 @@ static const netclass_t* resolve_call_chain_prefix_class(Design*des, NetScope*sc
if (link->peek_chain_prefix() == 0) {
symbol_search_results sr;
if (!symbol_search(link, des, scope, link->peek_path(),
link->lexical_pos(), &sr, true)) {
link->lexical_pos(), &sr,
SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE)) {
return 0;
}
if (!sr.is_scope() || sr.scope->type() != NetScope::FUNC) {
@ -2102,7 +2103,8 @@ unsigned PECallFunction::test_width(Design*des, NetScope*scope,
// Search for the symbol. This should turn up a scope.
symbol_search_results search_results;
bool search_flag = symbol_search(this, des, scope, path_, lexical_pos(),
&search_results, true);
&search_results,
SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE);
if (debug_elaborate) {
cerr << get_fileline() << ": PECallFunction::test_width: "
@ -3242,7 +3244,8 @@ NetExpr* PECallFunction::elaborate_expr_(Design*des, NetScope*scope,
// Search for the symbol. This should turn up a scope.
symbol_search_results search_results;
bool search_flag = symbol_search(this, des, scope, path_, lexical_pos(),
&search_results, true);
&search_results,
SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE);
if (debug_elaborate) {
cerr << get_fileline() << ": PECallFunction::elaborate_expr: "

3
elaborate.cc
View File

@ -3957,7 +3957,8 @@ NetProc* PCallTask::elaborate_usr(Design*des, NetScope*scope) const
NetScope *task = nullptr;
NetScope *func_scope = nullptr;
if (symbol_search(this, des, scope, call_path, lexical_pos(),
&search_results, true)) {
&search_results,
SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE)) {
if (!search_results.require_non_type(
this, des, "in a task or function call"))
return nullptr;

12
netmisc.h
View File

@ -129,6 +129,11 @@ struct symbol_search_results {
pform_name_t path_head;
};
enum symbol_search_flag_t {
SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE = 1U << 0,
SYMBOL_SEARCH_NO_SIGNAL_ELABORATION = 1U << 1
};
/*
* Test the search results and return true if this represents a function
* return value. That will be the case if the object is a net, the scope
@ -145,15 +150,16 @@ static inline bool test_function_return_value(const symbol_search_results&search
extern bool symbol_search(const LineInfo *li, Design *des, NetScope *scope,
pform_name_t path, unsigned int lexical_pos,
struct symbol_search_results *res);
struct symbol_search_results *res,
unsigned int flags = 0);
/* The forward-reference flag applies only to the terminal name. Prefix
components still use lexical_pos. */
components still use lexical_pos. Other flags apply to the complete path. */
extern bool symbol_search(const LineInfo *li, Design *des, NetScope *scope,
const pform_scoped_name_t &path,
unsigned int lexical_pos,
struct symbol_search_results *res,
bool allow_terminal_forward_reference = false);
unsigned int flags = 0);
extern bool check_interface_modport_access(const LineInfo *li, Design *des,
const symbol_search_results &res,

37
symbol_search.cc
View File

@ -55,7 +55,7 @@ static scope_object_search_result_t symbol_search_scope_objects(
const LineInfo *li, Design *des, NetScope *scope,
NetScope *start_scope, const pform_name_t &path,
const name_component_t &path_tail, unsigned int visibility_pos,
struct symbol_search_results *res)
struct symbol_search_results *res, unsigned int flags)
{
// Special case `super` keyword. Return the `this` object, but
// with the type of the base class.
@ -206,6 +206,12 @@ static scope_object_search_result_t symbol_search_scope_objects(
// been elaborated yet.
if (PWire *wire = scope->find_signal_placeholder(path_tail.name)) {
if (wire->lexical_pos() <= visibility_pos) {
if (flags & SYMBOL_SEARCH_NO_SIGNAL_ELABORATION) {
// The signal still hides matching symbols in outer
// scopes. Stop the lookup without elaborating it.
return scope_object_search_result_t::failed;
}
NetNet *net = wire->elaborate_sig(des, scope);
if (!net)
return scope_object_search_result_t::failed;
@ -322,7 +328,8 @@ static bool symbol_search_(const LineInfo *li, Design *des, NetScope *scope,
pform_name_t path, unsigned int lexical_pos,
unsigned int prefix_lexical_pos,
struct symbol_search_results *res,
NetScope *start_scope, bool scope_is_bound)
NetScope *start_scope, bool scope_is_bound,
unsigned int flags)
{
assert(scope);
@ -349,10 +356,12 @@ static bool symbol_search_(const LineInfo *li, Design *des, NetScope *scope,
// recursively. Ideally, the result is a scope that we search
// for the tail key, but there are other special cases as well.
if (! path.empty()) {
const unsigned int prefix_flags =
flags & ~SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE;
bool flag = symbol_search_(li, des, scope, path,
prefix_lexical_pos,
prefix_lexical_pos, res,
start_scope, scope_is_bound);
start_scope, scope_is_bound, prefix_flags);
if (! flag)
return false;
@ -460,7 +469,7 @@ static bool symbol_search_(const LineInfo *li, Design *des, NetScope *scope,
scope_object_search_result_t object_result =
symbol_search_scope_objects(
li, des, scope, start_scope, path, path_tail,
visibility_pos, res);
visibility_pos, res, flags);
if (object_result == scope_object_search_result_t::found)
return true;
if (object_result == scope_object_search_result_t::failed)
@ -577,16 +586,20 @@ static bool symbol_search_(const LineInfo *li, Design *des, NetScope *scope,
bool symbol_search(const LineInfo *li, Design *des, NetScope *scope,
pform_name_t path, unsigned int lexical_pos,
struct symbol_search_results *res)
struct symbol_search_results *res, unsigned int flags)
{
return symbol_search_(li, des, scope, path, lexical_pos, lexical_pos,
res, scope, false);
const bool allow_forward_reference =
flags & SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE;
const unsigned int terminal_lexical_pos = allow_forward_reference
? UINT_MAX : lexical_pos;
return symbol_search_(li, des, scope, path, terminal_lexical_pos,
lexical_pos,
res, scope, false, flags);
}
bool symbol_search(const LineInfo *li, Design *des, NetScope *scope,
const pform_scoped_name_t &path, unsigned int lexical_pos,
struct symbol_search_results *res,
bool allow_terminal_forward_reference)
struct symbol_search_results *res, unsigned int flags)
{
NetScope *search_scope = scope;
bool scope_is_bound = false;
@ -598,11 +611,13 @@ bool symbol_search(const LineInfo *li, Design *des, NetScope *scope,
scope_is_bound = true;
}
const unsigned int terminal_lexical_pos = allow_terminal_forward_reference
const bool allow_forward_reference =
flags & SYMBOL_SEARCH_ALLOW_FORWARD_REFERENCE;
const unsigned int terminal_lexical_pos = allow_forward_reference
? UINT_MAX : lexical_pos;
return symbol_search_(li, des, search_scope, path.name,
terminal_lexical_pos, lexical_pos, res,
search_scope, scope_is_bound);
search_scope, scope_is_bound, flags);
}
bool check_interface_modport_access(const LineInfo *li, Design *des,