standalone: Add command line flags for target properties

For testing codegen for different platforms on the host system.

nac3standalone/src/main.rs

@@ -53,6 +53,18 @@ struct CommandLineArgs {
     /// Whether to use LLVM's Legacy Pass Manager for optimizations.
     #[arg(long, default_value_t = false)]
     legacy_pm: bool,
+
+    /// The target triple to compile for.
+    #[arg(long)]
+    triple: Option<String>,
+
+    /// The target CPU to compile for.
+    #[arg(long)]
+    mcpu: Option<String>,
+
+    /// Additional target features to enable/disable, specified using the `+`/`-` prefixes.
+    #[arg(long)]
+    target_features: Option<String>,
 }
 
 fn handle_typevar_definition(
@@ -187,7 +199,19 @@ fn main() {
         opt_level,
         emit_llvm,
         legacy_pm,
+        triple,
+        mcpu,
+        target_features,
     } = cli;
+
+    Target::initialize_all(&InitializationConfig::default());
+
+    let host_target_machine = CodeGenTargetMachineOptions::from_host();
+    let triple = triple.unwrap_or(host_target_machine.triple.clone());
+    let mcpu = mcpu
+        .map(|arg| if arg == "native" { host_target_machine.cpu.clone() } else { arg })
+        .unwrap_or_default();
+    let target_features = target_features.unwrap_or_default();
     let opt_level = match opt_level {
         0 => OptimizationLevel::None,
         1 => OptimizationLevel::Less,
@@ -196,8 +220,6 @@ fn main() {
         _ => OptimizationLevel::Aggressive,
     };
 
-    Target::initialize_all(&InitializationConfig::default());
-
     let program = match fs::read_to_string(file_name.clone()) {
         Ok(program) => program,
         Err(err) => {
@@ -283,7 +305,12 @@ fn main() {
     let llvm_options = CodeGenLLVMOptions {
         opt_level,
         legacy_pm,
-        target: CodeGenTargetMachineOptions::from_host_triple(),
+        target: CodeGenTargetMachineOptions {
+            triple,
+            cpu: mcpu,
+            features: target_features,
+            ..host_target_machine
+        },
         emit_llvm,
     };