Extract target triple and linking logic

compiler/build/src/target.rs

@@ -0,0 +1,76 @@
+use inkwell::targets::{
+    CodeModel, InitializationConfig, RelocMode, Target, TargetMachine, TargetTriple,
+};
+use inkwell::OptimizationLevel;
+use target_lexicon::{Architecture, OperatingSystem, Triple};
+
+pub fn target_triple_str(target: &Triple) -> &'static str {
+    // Best guide I've found on how to determine these magic strings:
+    //
+    // https://stackoverflow.com/questions/15036909/clang-how-to-list-supported-target-architectures
+    match target {
+        Triple {
+            architecture: Architecture::X86_64,
+            operating_system: OperatingSystem::Linux,
+            ..
+        } => "x86_64-unknown-linux-gnu",
+        Triple {
+            architecture: Architecture::X86_64,
+            operating_system: OperatingSystem::Darwin,
+            ..
+        } => "x86_64-unknown-darwin10",
+        _ => panic!("TODO gracefully handle unsupported target: {:?}", target),
+    }
+}
+
+/// NOTE: arch_str is *not* the same as the beginning of the magic target triple
+/// string! For example, if it's "x86-64" here, the magic target triple string
+/// will begin with "x86_64" (with an underscore) instead.
+pub fn arch_str(target: &Triple) -> &'static str {
+    // Best guide I've found on how to determine these magic strings:
+    //
+    // https://stackoverflow.com/questions/15036909/clang-how-to-list-supported-target-architectures
+    match target.architecture {
+        Architecture::X86_64 => {
+            Target::initialize_x86(&InitializationConfig::default());
+
+            "x86-64"
+        }
+        Architecture::Arm(_) if cfg!(feature = "target-arm") => {
+            // NOTE: why not enable arm and wasm by default?
+            //
+            // We had some trouble getting them to link properly. This may be resolved in the
+            // future, or maybe it was just some weird configuration on one machine.
+            Target::initialize_arm(&InitializationConfig::default());
+
+            "arm"
+        }
+        Architecture::Wasm32 if cfg!(feature = "target-webassembly") => {
+            Target::initialize_webassembly(&InitializationConfig::default());
+
+            "wasm32"
+        }
+        _ => panic!(
+            "TODO gracefully handle unsupported target architecture: {:?}",
+            target.architecture
+        ),
+    }
+}
+
+pub fn target_machine(
+    target: &Triple,
+    opt: OptimizationLevel,
+    reloc: RelocMode,
+    model: CodeModel,
+) -> Option<TargetMachine> {
+    let arch = arch_str(target);
+
+    Target::from_name(arch).unwrap().create_target_machine(
+        &TargetTriple::create(target_triple_str(target)),
+        arch,
+        "+avx2", // TODO this string was used uncritically from an example, and should be reexamined
+        opt,
+        reloc,
+        model,
+    )
+}