nasm/xa65: add the --allow-unused option

Since the addition of the check() function in commit 6a9dea943c07 ("Add
a new 'check' stage in assemble()"), it can be annoying to some users
that the check for unused/unreferenced object applies by default. Hence,
add a flag so this can be disabled.

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

3 files changed, 31 insertions, 2 deletions

diff --git a/crates/nasm/src/main.rs b/crates/nasm/src/main.rs
index 6541d9c..b865fa7 100644
--- a/crates/nasm/src/main.rs
+++ b/crates/nasm/src/main.rs
@@ -21,6 +21,7 @@ struct Args {
     defines: Vec<(String, u8)>,
     asan: bool,
     info: bool,
+    allow_unused: bool,
 }
 
 // Print the help message and quit.
@@ -29,6 +30,7 @@ fn print_help() {
     println!("usage: nasm [OPTIONS] <FILE>\n");
     println!("Options:");
     println!("  -a, --asan\t\tEnable the Address Sanitizer.");
+    println!("  --allow-unused\t\tAllow unused .proc's or unreferenced objects.");
     println!("  -c, --config <FILE>\tLinker configuration to be used, whether an identifier or a file path.");
     println!(
         "  -D <NAME>(=VALUE)\tDefine an 8-bit variable on the global scope ('VALUE' defaults to '1')"
@@ -108,6 +110,7 @@ fn parse_arguments() -> Args {
     while let Some(arg) = args.next() {
         match arg.as_str() {
             "-a" | "--asan" => res.asan = true,
+            "--allow-unused" => res.allow_unused = true,
             "-c" | "--config" => match res.config {
                 Some(_) => die("only specify the '-C/--config' flag once".to_string()),
                 None => match args.next() {
@@ -330,6 +333,7 @@ fn main() {
         args.config.unwrap_or("nrom".to_string()).as_str(),
         &args.defines,
         &source,
+        args.allow_unused,
         args.asan,
     );
 
diff --git a/crates/xa65/src/main.rs b/crates/xa65/src/main.rs
index abf866b..77e5127 100644
--- a/crates/xa65/src/main.rs
+++ b/crates/xa65/src/main.rs
@@ -18,6 +18,7 @@ struct Args {
     no_errors: bool,
     strict: bool,
     stats: bool,
+    allow_unused: bool,
 }
 
 // Print the help message and quit.
@@ -25,6 +26,7 @@ fn print_help() {
     println!("Bridge between 'nasm' and 'ca65'.\n");
     println!("usage: xa65 [OPTIONS] <FILE>\n");
     println!("Options:");
+    println!("  --allow-unused\tPass the '--allow-unused' flag to 'nasm'.");
     println!("  -b, --bin <PROGRAM>\tAlternative to the binary for 'nasm'.");
     println!("  -C, --config <FILE>\tLinker configuration to be used, whether an identifier or a file path.");
     println!("  -h, --help\t\tPrint this message.");
@@ -48,6 +50,7 @@ fn parse_arguments() -> Args {
 
     while let Some(arg) = args.next() {
         match arg.as_str() {
+            "--allow-unused" => res.allow_unused = true,
             "-b" | "--bin" => match res.bin {
                 Some(_) => die("only specify the '-b/--bin' flag once".to_string()),
                 None => match args.next() {
@@ -263,6 +266,9 @@ fn main() {
     if args.stats {
         cmd.arg("--stats");
     }
+    if args.allow_unused {
+        cmd.arg("--allow-unused");
+    }
 
     // Actually run the command.
     match cmd.status() {
diff --git a/lib/xixanta/src/assembler.rs b/lib/xixanta/src/assembler.rs
index 67d1340..47c662b 100644
--- a/lib/xixanta/src/assembler.rs
+++ b/lib/xixanta/src/assembler.rs
@@ -136,6 +136,10 @@ struct Assembler<'a> {
     // (0x6000-0x7FFF).
     accessing_working_ram: bool,
 
+    // Allow unused .proc's or unreferenced objects on the final binary. In
+    // other words, don't look for unreferenced bundles at the 'check' stage.
+    allow_unused: bool,
+
     // Whether the Address Sanitizer is enabled or not.
     asan_enabled: bool,
 
@@ -217,6 +221,7 @@ pub fn assemble(
     mapping: &str,
     defines: &[(String, u8)],
     source: &SourceInfo,
+    allow_unused: bool,
     asan: bool,
 ) -> AssemblerResult {
     let config = match get_mapping_configuration(mapping) {
@@ -239,7 +244,7 @@ pub fn assemble(
         }
     };
 
-    assemble_with_mapping(reader, config, defines, source, asan)
+    assemble_with_mapping(reader, config, defines, source, allow_unused, asan)
 }
 
 /// Read the contents from the `reader` as a source file and produce a list of
@@ -253,6 +258,7 @@ pub fn assemble_with_mapping(
     mapping: Vec<Mapping>,
     defines: &[(String, u8)],
     source: &SourceInfo,
+    allow_unused: bool,
     asan: bool,
 ) -> AssemblerResult {
     // Save the original current working directory in case it changes after a
@@ -262,6 +268,7 @@ pub fn assemble_with_mapping(
     let mut asm = Assembler::new(mapping);
     let mut memory = MemoryResult::default();
     asm.asan_enabled = asan;
+    asm.allow_unused = allow_unused;
 
     // First of all, parse the input so we get a list of nodes we can work
     // with.
@@ -415,6 +422,7 @@ impl<'a> Assembler<'a> {
             warnings: vec![],
             sources: vec![],
             accessing_working_ram: false,
+            allow_unused: false,
             asan_enabled: false,
             asan_next_ignore: false,
             asan_next_reserve: 1,
@@ -1176,7 +1184,7 @@ impl<'a> Assembler<'a> {
                 };
 
                 // Check if this variable/proc was ever accessed.
-                if bundle.accessed == 0 {
+                if !self.allow_unused && bundle.accessed == 0 {
                     // If this was a .proc definition then we are certain that
                     // this is dead code, which is a really crappy situation.
                     if matches!(bundle.object_type, ObjectType::Proc) {
@@ -3455,6 +3463,7 @@ mod tests {
             &[],
             &SourceInfo::default(),
             false,
+            false,
         )
     }
 
@@ -3845,6 +3854,7 @@ mod tests {
             empty(),
             &[],
             &SourceInfo::default(),
+            false,
             true,
         );
 
@@ -3868,6 +3878,7 @@ mod tests {
             empty(),
             &[],
             &SourceInfo::default(),
+            false,
             true,
         );
 
@@ -3890,6 +3901,7 @@ mod tests {
             empty(),
             &[],
             &SourceInfo::default(),
+            false,
             true,
         );
 
@@ -3914,6 +3926,7 @@ mod tests {
             empty(),
             &[],
             &SourceInfo::default(),
+            false,
             true,
         );
 
@@ -5552,6 +5565,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         assert_eq!(res.bundles.len(), 0x11);
@@ -5595,6 +5609,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         let bundles = &res.bundles[0x11..];
@@ -5670,6 +5685,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         let bundles = &res.bundles[0x12..]; // Ignoring HEADER + first two ONE
@@ -5719,6 +5735,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         let bundles = &res.bundles[0x11..]; // Ignoring HEADER + first nop
@@ -5775,6 +5792,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         let bundles = &res.bundles[0x10..];
@@ -5803,6 +5821,7 @@ lda #Variable
             &[],
             &SourceInfo::default(),
             false,
+            false,
         );
 
         assert_eq!(