RGBLINK lists local symbols when encountering an unknown symbol reference (#1496)

src/link/object.cpp

@@ -564,8 +564,7 @@ void obj_ReadFile(char const *fileName, unsigned int fileID) {
 
 		readSymbol(file, symbol, fileName, nodes[fileID]);
 
-		if (symbol.type == SYMTYPE_EXPORT)
-			sym_AddSymbol(symbol);
+		sym_AddSymbol(symbol);
 		if (symbol.data.holds<Label>())
 			nbSymPerSect[symbol.data.get<Label>().sectionID]++;
 	}

src/link/patch.cpp

@@ -388,6 +388,7 @@ static int32_t computeRPNExpr(Patch const &patch, std::vector<Symbol> const &fil
 					    "Unknown symbol \"%s\"",
 					    fileSymbols[value].name.c_str()
 					);
+					sym_DumpLocalAliasedSymbols(fileSymbols[value].name);
 					isError = true;
 				} else if (symbol->data.holds<Label>()) {
 					Label const &label = symbol->data.get<Label>();

src/link/sdas_obj.cpp

@@ -382,6 +382,7 @@ void sdobj_ReadFile(FileStackNode const &where, FILE *file, std::vector<Symbol>
 			// Expected format: /[DR]ef[0-9A-F]+/i
 			if (token[0] == 'R' || token[0] == 'r') {
 				symbol.type = SYMTYPE_IMPORT;
+				sym_AddSymbol(symbol);
 				// TODO: hard error if the rest is not zero
 			} else if (token[0] != 'D' && token[0] != 'd') {
 				fatal(&where, lineNo, "'S' line is neither \"Def\" nor \"Ref\"");

src/link/symbol.cpp

@@ -4,6 +4,7 @@
 
 #include <stdlib.h>
 #include <unordered_map>
+#include <vector>
 
 #include "helpers.hpp" // assume
 
@@ -11,6 +12,7 @@
 #include "link/section.hpp"
 
 std::unordered_map<std::string, Symbol *> symbols;
+std::unordered_map<std::string, std::vector<Symbol *>> localSymbols;
 
 void sym_ForEach(void (*callback)(Symbol &)) {
 	for (auto &it : symbols)
@@ -18,6 +20,12 @@ void sym_ForEach(void (*callback)(Symbol &)) {
 }
 
 void sym_AddSymbol(Symbol &symbol) {
+	if (symbol.type != SYMTYPE_EXPORT) {
+		if (symbol.type != SYMTYPE_IMPORT)
+			localSymbols[symbol.name].push_back(&symbol);
+		return;
+	}
+
 	Symbol *other = sym_GetSymbol(symbol.name);
 	int32_t *symValue = symbol.data.holds<int32_t>() ? &symbol.data.get<int32_t>() : nullptr;
 	int32_t *otherValue =
@@ -41,3 +49,30 @@ Symbol *sym_GetSymbol(std::string const &name) {
 	auto search = symbols.find(name);
 	return search != symbols.end() ? search->second : nullptr;
 }
+
+void sym_DumpLocalAliasedSymbols(std::string const &name) {
+	std::vector<Symbol *> const &locals = localSymbols[name];
+	int count = 0;
+	for (Symbol *local : locals) {
+		if (count++ == 3) {
+			size_t remaining = locals.size() - 3;
+			bool plural = remaining != 1;
+			fprintf(
+			    stderr,
+			    "    ...and %zu more symbol%s with that name %s defined but not exported\n",
+			    remaining,
+			    plural ? "s" : "",
+			    plural ? "are" : "is"
+			);
+			break;
+		}
+		fprintf(
+		    stderr,
+		    "    A %s with that name is defined but not exported at ",
+		    local->data.holds<Label>() ? "label" : "constant"
+		);
+		assume(local->src);
+		local->src->dump(local->lineNo);
+		putc('\n', stderr);
+	}
+}