fstdata: Handle square/angle bracket replacemnt, change memory handling

When writing VCDs smtbmc replaces square brackets with angle brackets to
avoid the issues with VCD readers misinterpreting such signal names.

For memory addresses it also uses angle brackets and hexadecimal
addresses, while other tools will use square brackets and decimal
addresses.

Previously the code handled both forms of memory addresses, assuming
that any signal that looks like a memory address is a memory address.
This is not the case when the user uses regular signals whose names
include square brackets _or_ when the verific frontend generates such
names to represent various constructs.

With this change all angular brackets are turned into square brackets
when reading the trace _and_ when performing a signal lookup. This means
no matter which kind of brackets are used in the design or in the VCD
signals will be matched. This will not handle multiple signals that are
the same apart from replacing square/angle brackets, but this will cause
issues during the VCD writing of smtbmc already.

It still uses the distinction between square and angle brackets for
memories to decide whether the address is hex or decimal, but even if
something looks like a memory and is added to the `memory_to_handle`
data, the plain signal added to `name_to_handle` is used as-is, without
rewriting the address.

This last change is needed to successfully match verific generated
signal names that look like memory addresses while keeping memories
working at the same time. It may cause regressions when VCD generation
was done with a design that had memories but simulation is done with a
design where the memories were mapped to registers. This seems like an
unusual setup, but could be worked around with some further changes
should this be required.

kernel/fstdata.cc

@@ -78,7 +78,18 @@ uint64_t FstData::getStartTime() { return fstReaderGetStartTime(ctx); }
 
 uint64_t FstData::getEndTime() { return fstReaderGetEndTime(ctx); }
 
+static void normalize_brackets(std::string &str)
+{
+	for (auto &c : str) {
+		if (c == '<')
+			c = '[';
+		else if (c == '>')
+			c = ']';
+	}
+}
+
 fstHandle FstData::getHandle(std::string name) { 
+	normalize_brackets(name);
 	if (name_to_handle.find(name) != name_to_handle.end())
 		return name_to_handle[name];
 	else 
@@ -120,6 +131,7 @@ void FstData::extractVarNames()
 				var.is_reg = (fstVarType)h->u.var.typ == FST_VT_VCD_REG;
 				var.name = remove_spaces(h->u.var.name);
 				var.scope = fst_scope_name;
+				normalize_brackets(var.scope);
 				var.width = h->u.var.length;
 				vars.push_back(var);
 				if (!var.is_alias)
@@ -134,35 +146,34 @@ void FstData::extractVarNames()
 				if (clean_name[0]=='\\')
 					clean_name = clean_name.substr(1);
 				size_t pos = clean_name.find_last_of("<");
-				if (pos != std::string::npos) {
+				if (pos != std::string::npos && clean_name.back() == '>') {
 					std::string mem_cell = clean_name.substr(0, pos);
+					normalize_brackets(mem_cell);
 					std::string addr = clean_name.substr(pos+1);
 					addr.pop_back(); // remove closing bracket
 					char *endptr;
 					int mem_addr = strtol(addr.c_str(), &endptr, 16);
 					if (*endptr) {
-						log_warning("Error parsing memory address in : %s\n", clean_name.c_str());
+						log_debug("Error parsing memory address in : %s\n", clean_name.c_str());
 					} else {
 						memory_to_handle[var.scope+"."+mem_cell][mem_addr] = var.id;
-						name_to_handle[stringf("%s.%s[%d]",var.scope.c_str(),mem_cell.c_str(),mem_addr)] = h->u.var.handle;
-						continue;
 					}
 				}
 				pos = clean_name.find_last_of("[");
-				if (pos != std::string::npos) {
+				if (pos != std::string::npos && clean_name.back() == ']') {
 					std::string mem_cell = clean_name.substr(0, pos);
+					normalize_brackets(mem_cell);
 					std::string addr = clean_name.substr(pos+1);
 					addr.pop_back(); // remove closing bracket
 					char *endptr;
 					int mem_addr = strtol(addr.c_str(), &endptr, 10);
 					if (*endptr) {
-						log_warning("Error parsing memory address in : %s\n", clean_name.c_str());
+						log_debug("Error parsing memory address in : %s\n", clean_name.c_str());
 					} else {
 						memory_to_handle[var.scope+"."+mem_cell][mem_addr] = var.id;
-						name_to_handle[stringf("%s.%s[%d]",var.scope.c_str(),mem_cell.c_str(),mem_addr)] = h->u.var.handle;
-						continue;
 					}
 				}
+				normalize_brackets(clean_name);
 				name_to_handle[var.scope+"."+clean_name] = h->u.var.handle;
 				break;
 			}