Emit auxiliary files even if asserts fail (#2104)

Closes #2100

include/link/output.hpp

@@ -11,7 +11,8 @@ void out_AddSection(Section const &section);
 // Finds an assigned section overlapping another one.
 Section const *out_OverlappingSection(Section const &section);
 
-// Writes all output (bin, sym, map) files.
-void out_WriteFiles();
+void out_WriteROMIfAny();
+void out_WriteSymIfAny();
+void out_WriteMapIfAny();
 
 #endif // RGBDS_LINK_OUTPUT_HPP

src/link/main.cpp

@@ -433,14 +433,14 @@ int main(int argc, char *argv[]) {
 		sectionTypeInfo[SECTTYPE_VRAM].lastBank = 0;
 	}
 
-	// Read all object files first,
+	// Read all object files...
 	size_t nbFiles = localOptions.inputFileNames.size();
 	obj_Setup(nbFiles);
 	for (size_t i = 0; i < nbFiles; ++i) {
 		obj_ReadFile(localOptions.inputFileNames[i], nbFiles - i - 1);
 	}
 
-	// apply the linker script's modifications,
+	// Apply the linker script's modifications...
 	if (localOptions.linkerScriptName) {
 		verbosePrint(VERB_NOTICE, "Reading linker script...\n");
 
@@ -453,16 +453,25 @@ int main(int argc, char *argv[]) {
 		requireZeroErrors();
 	}
 
-	// then process them,
+	// Attempt to generate a layout...
 	sect_DoSanityChecks();
 	requireZeroErrors();
 	assign_AssignSections();
+
+	// Emit the symbol and/or map files now (if requested on the CLI),
+	// so that more link-time info is available to debug any failing assertions.
+	// This is safe to do, since we have a valid layout at this point;
+	// assertions only check user-level assumptions made about it.
+	out_WriteSymIfAny();
+	out_WriteMapIfAny();
+
+	// Make any last-minute verifications...
 	patch_CheckAssertions();
 
-	// and finally output the result.
+	// And, finally, make the ROM and emit it!
 	patch_ApplyPatches();
 	requireZeroErrors();
-	out_WriteFiles();
+	out_WriteROMIfAny();
 
 	return 0;
 }

src/link/output.cpp

@@ -204,7 +204,7 @@ static void
 	}
 }
 
-static void writeROM() {
+void out_WriteROMIfAny() {
 	if (options.outputFileName) {
 		char const *outputFileName = options.outputFileName->c_str();
 		if (*options.outputFileName != "-") {
@@ -536,7 +536,7 @@ static void writeMapSummary() {
 	}
 }
 
-static void writeSym() {
+void out_WriteSymIfAny() {
 	if (!options.symFileName) {
 		return;
 	}
@@ -587,7 +587,7 @@ static void writeSym() {
 	}
 }
 
-static void writeMap() {
+void out_WriteMapIfAny() {
 	if (!options.mapFileName) {
 		return;
 	}
@@ -615,9 +615,3 @@ static void writeMap() {
 		}
 	}
 }
-
-void out_WriteFiles() {
-	writeROM();
-	writeSym();
-	writeMap();
-}