Split out an optional "llvm" feature

Also move OptLevel out of roc_gen (which
should really be called gen_llvm) and into roc_mono,
so it's no longer coupled to LLVM.

Cargo.toml

@@ -32,6 +32,12 @@ members = [
     "roc_std",
     "docs"
 ]
+# Needed to be able to run `cargo run -p roc_cli --no-default-features` -
+# see www/build.sh for more.
+#
+# Without the `-p` flag, cargo ignores `--no-default-features` when you have a
+# workspace, and without `resolver = "2"` here, you can't use `-p` like this.
+resolver = "2"
 
 # Optimizations based on https://deterministic.space/high-performance-rust.html
 [profile.release]

cli/Cargo.toml

@@ -15,7 +15,11 @@ test = false
 bench = false
 
 [features]
-default = ["target-x86"]
+default = ["target-x86", "llvm"]
+
+# This is a separate feature because when we generate docs on Netlify,
+# it doesn't have LLVM installed. (Also, it doesn't need to do code gen.)
+llvm = ["inkwell", "roc_gen", "roc_build/llvm"]
 
 target-x86 = []
 
@@ -45,8 +49,8 @@ roc_unify = { path = "../compiler/unify" }
 roc_solve = { path = "../compiler/solve" }
 roc_mono = { path = "../compiler/mono" }
 roc_load = { path = "../compiler/load" }
-roc_gen = { path = "../compiler/gen" }
-roc_build = { path = "../compiler/build" }
+roc_gen = { path = "../compiler/gen", optional = true }
+roc_build = { path = "../compiler/build", default-features = false }
 roc_fmt = { path = "../compiler/fmt" }
 roc_reporting = { path = "../compiler/reporting" }
 roc_editor = { path = "../editor" }
@@ -62,7 +66,7 @@ inlinable_string = "0.1"
 libc = "0.2"
 libloading = "0.6"
 
-inkwell = { path = "../vendor/inkwell" }
+inkwell = { path = "../vendor/inkwell", optional = true }
 target-lexicon = "0.10"
 tempfile = "3.1.0"
 
@@ -74,7 +78,7 @@ quickcheck = "0.8"
 quickcheck_macros = "0.8"
 serial_test = "0.5"
 tempfile = "3.1.0"
-criterion = { git = "https://github.com/Anton-4/criterion.rs"} 
+criterion = { git = "https://github.com/Anton-4/criterion.rs"}
 cli_utils = { path = "cli_utils" }
 # Keep the commented deps, they are commented because they require nightly rust
 # criterion-perf-events = "0.1.3"

cli/src/build.rs

@@ -5,8 +5,8 @@ use roc_build::{
 };
 use roc_can::builtins::builtin_defs_map;
 use roc_collections::all::MutMap;
-use roc_gen::llvm::build::OptLevel;
 use roc_load::file::LoadingProblem;
+use roc_mono::ir::OptLevel;
 use std::path::PathBuf;
 use std::time::{Duration, SystemTime};
 use target_lexicon::Triple;
@@ -32,6 +32,7 @@ pub struct BuiltFile {
     pub total_time: Duration,
 }
 
+#[cfg(feature = "llvm")]
 pub fn build_file<'a>(
     arena: &'a Bump,
     target: &Triple,

cli/src/lib.rs

@@ -1,12 +1,12 @@
 #[macro_use]
 extern crate clap;
 
-use build::{build_file, BuildOutcome, BuiltFile};
+use build::{BuildOutcome, BuiltFile};
 use bumpalo::Bump;
 use clap::{App, AppSettings, Arg, ArgMatches};
 use roc_build::link::LinkType;
-use roc_gen::llvm::build::OptLevel;
 use roc_load::file::LoadingProblem;
+use roc_mono::ir::OptLevel;
 use std::env;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -116,7 +116,9 @@ pub enum BuildConfig {
     BuildAndRun { roc_file_arg_index: usize },
 }
 
+#[cfg(feature = "llvm")]
 pub fn build(target: &Triple, matches: &ArgMatches, config: BuildConfig) -> io::Result<i32> {
+    use build::build_file;
     use BuildConfig::*;
 
     let arena = Bump::new();

cli/src/main.rs

@@ -1,11 +1,19 @@
 use roc_cli::{
-    build, build_app, docs, repl, BuildConfig, CMD_BUILD, CMD_DOCS, CMD_EDIT, CMD_REPL, CMD_RUN,
+    build_app, docs, repl, BuildConfig, CMD_BUILD, CMD_DOCS, CMD_EDIT, CMD_REPL, CMD_RUN,
     DIRECTORY_OR_FILES, ROC_FILE,
 };
 use std::io;
 use std::path::{Path, PathBuf};
 use target_lexicon::Triple;
 
+#[cfg(feature = "llvm")]
+use roc_cli::build;
+
+#[cfg(not(feature = "llvm"))]
+fn build(_target: &Triple, _matches: &clap::ArgMatches, _config: BuildConfig) -> io::Result<i32> {
+    panic!("Building without LLVM is not currently supported.");
+}
+
 fn main() -> io::Result<()> {
     let matches = build_app().get_matches();
 

cli/src/repl.rs

@@ -1,15 +1,12 @@
 use const_format::concatcp;
+#[cfg(feature = "llvm")]
 use gen::{gen_and_eval, ReplOutput};
-use roc_gen::llvm::build::OptLevel;
 use roc_parse::parser::{EExpr, SyntaxError};
-use rustyline::error::ReadlineError;
 use rustyline::highlight::{Highlighter, PromptInfo};
 use rustyline::validate::{self, ValidationContext, ValidationResult, Validator};
-use rustyline::Editor;
 use rustyline_derive::{Completer, Helper, Hinter};
 use std::borrow::Cow;
 use std::io;
-use target_lexicon::Triple;
 
 const BLUE: &str = "\u{001b}[36m";
 const PINK: &str = "\u{001b}[35m";
@@ -30,7 +27,9 @@ pub const INSTRUCTIONS: &str = "Enter an expression, or :help, or :exit/:q.\n";
 pub const PROMPT: &str = concatcp!("\n", BLUE, "»", END_COL, " ");
 pub const CONT_PROMPT: &str = concatcp!(BLUE, "…", END_COL, " ");
 
+#[cfg(feature = "llvm")]
 mod eval;
+#[cfg(feature = "llvm")]
 mod gen;
 
 #[derive(Completer, Helper, Hinter)]
@@ -107,7 +106,16 @@ impl Validator for InputValidator {
     }
 }
 
+#[cfg(not(feature = "llvm"))]
 pub fn main() -> io::Result<()> {
+    panic!("The REPL currently requires being built with LLVM.");
+}
+
+#[cfg(feature = "llvm")]
+pub fn main() -> io::Result<()> {
+    use rustyline::error::ReadlineError;
+    use rustyline::Editor;
+
     // To debug rustyline:
     // <UNCOMMENT> env_logger::init();
     // <RUN WITH:> RUST_LOG=rustyline=debug cargo run repl 2> debug.log
@@ -226,7 +234,11 @@ fn report_parse_error(fail: SyntaxError) {
     println!("TODO Gracefully report parse error in repl: {:?}", fail);
 }
 
+#[cfg(feature = "llvm")]
 fn eval_and_format<'a>(src: &str) -> Result<String, SyntaxError<'a>> {
+    use roc_mono::ir::OptLevel;
+    use target_lexicon::Triple;
+
     gen_and_eval(src.as_bytes(), Triple::host(), OptLevel::Normal).map(|output| match output {
         ReplOutput::NoProblems { expr, expr_type } => {
             format!("\n{} {}:{} {}", expr, PINK, END_COL, expr_type)

cli/src/repl/gen.rs

@@ -8,9 +8,9 @@ use roc_can::builtins::builtin_defs_map;
 use roc_collections::all::{MutMap, MutSet};
 use roc_fmt::annotation::Formattable;
 use roc_fmt::annotation::{Newlines, Parens};
-use roc_gen::llvm::build::OptLevel;
 use roc_gen::llvm::externs::add_default_roc_externs;
 use roc_load::file::LoadingProblem;
+use roc_mono::ir::OptLevel;
 use roc_parse::parser::SyntaxError;
 use roc_types::pretty_print::{content_to_string, name_all_type_vars};
 use std::path::{Path, PathBuf};

compiler/build/Cargo.toml

@@ -19,7 +19,7 @@ roc_unify = { path = "../unify" }
 roc_solve = { path = "../solve" }
 roc_mono = { path = "../mono" }
 roc_load = { path = "../load" }
-roc_gen = { path = "../gen" }
+roc_gen = { path = "../gen", optional = true }
 roc_reporting = { path = "../reporting" }
 im    = "14" # im and im-rc should always have the same version!
 im-rc = "14" # im and im-rc should always have the same version!
@@ -28,7 +28,7 @@ inlinable_string = "0.1.0"
 libloading = "0.6"
 tempfile = "3.1.0"
 serde_json = "1.0"
-inkwell = { path = "../../vendor/inkwell" }
+inkwell = { path = "../../vendor/inkwell", optional = true }
 target-lexicon = "0.10"
 
 [dev-dependencies]
@@ -39,6 +39,10 @@ quickcheck = "0.8"
 quickcheck_macros = "0.8"
 
 [features]
+default = ["llvm"]
 target-arm = []
 target-aarch64 = []
 target-webassembly = []
+# This is a separate feature because when we generate docs on Netlify,
+# it doesn't have LLVM installed. (Also, it doesn't need to do code gen.)
+llvm = ["inkwell", "roc_gen"]

compiler/build/src/link.rs

@@ -1,16 +1,14 @@
-use crate::target;
 use crate::target::arch_str;
-use inkwell::module::Module;
-use inkwell::targets::{CodeModel, FileType, RelocMode};
+#[cfg(feature = "llvm")]
 use libloading::{Error, Library};
-use roc_gen::llvm::build::OptLevel;
+#[cfg(feature = "llvm")]
+use roc_mono::ir::OptLevel;
 use std::collections::HashMap;
 use std::env;
 use std::io;
 use std::path::{Path, PathBuf};
 use std::process::{Child, Command, Output};
 use target_lexicon::{Architecture, OperatingSystem, Triple};
-use tempfile::tempdir;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum LinkType {
@@ -360,6 +358,9 @@ fn link_linux(
     };
 
     let env_path = env::var("PATH").unwrap_or_else(|_| "".to_string());
+
+    init_arch(target);
+
     // NOTE: order of arguments to `ld` matters here!
     // The `-l` flags should go after the `.o` arguments
     Ok((
@@ -477,12 +478,16 @@ fn link_macos(
     ))
 }
 
+#[cfg(feature = "llvm")]
 pub fn module_to_dylib(
-    module: &Module,
+    module: &inkwell::module::Module,
     target: &Triple,
     opt_level: OptLevel,
 ) -> Result<Library, Error> {
-    let dir = tempdir().unwrap();
+    use crate::target::{self, convert_opt_level};
+    use inkwell::targets::{CodeModel, FileType, RelocMode};
+
+    let dir = tempfile::tempdir().unwrap();
     let filename = PathBuf::from("Test.roc");
     let file_path = dir.path().join(filename);
     let mut app_o_file = file_path;
@@ -492,7 +497,8 @@ pub fn module_to_dylib(
     // Emit the .o file using position-indepedent code (PIC) - needed for dylibs
     let reloc = RelocMode::PIC;
     let model = CodeModel::Default;
-    let target_machine = target::target_machine(target, opt_level.into(), reloc, model).unwrap();
+    let target_machine =
+        target::target_machine(target, convert_opt_level(opt_level), reloc, model).unwrap();
 
     target_machine
         .write_to_file(module, FileType::Object, &app_o_file)
@@ -529,3 +535,13 @@ fn validate_output(file_name: &str, cmd_name: &str, output: Output) {
         }
     }
 }
+
+#[cfg(feature = "llvm")]
+fn init_arch(target: &Triple) {
+    crate::target::init_arch(target);
+}
+
+#[cfg(not(feature = "llvm"))]
+fn init_arch(_target: &Triple) {
+    panic!("Tried to initialize LLVM when crate was not built with `feature = \"llvm\"` enabled");
+}

compiler/build/src/program.rs

@@ -1,13 +1,14 @@
-use crate::target;
-use bumpalo::Bump;
-use inkwell::context::Context;
-use inkwell::targets::{CodeModel, FileType, RelocMode};
+#[cfg(feature = "llvm")]
+use roc_gen::llvm::build::module_from_builtins;
+#[cfg(feature = "llvm")]
 pub use roc_gen::llvm::build::FunctionIterator;
-use roc_gen::llvm::build::{module_from_builtins, OptLevel};
+#[cfg(feature = "llvm")]
 use roc_load::file::MonomorphizedModule;
+#[cfg(feature = "llvm")]
+use roc_mono::ir::OptLevel;
+#[cfg(feature = "llvm")]
 use std::path::{Path, PathBuf};
-use std::time::{Duration, SystemTime};
-use target_lexicon::Triple;
+use std::time::Duration;
 
 #[derive(Debug, Clone, Copy, Default)]
 pub struct CodeGenTiming {
@@ -18,16 +19,24 @@ pub struct CodeGenTiming {
 // TODO how should imported modules factor into this? What if those use builtins too?
 // TODO this should probably use more helper functions
 // TODO make this polymorphic in the llvm functions so it can be reused for another backend.
+#[cfg(feature = "llvm")]
 #[allow(clippy::cognitive_complexity)]
 pub fn gen_from_mono_module(
-    arena: &Bump,
+    arena: &bumpalo::Bump,
     mut loaded: MonomorphizedModule,
     roc_file_path: &Path,
-    target: Triple,
+    target: target_lexicon::Triple,
     app_o_file: &Path,
     opt_level: OptLevel,
     emit_debug_info: bool,
 ) -> CodeGenTiming {
+    use crate::target::{self, convert_opt_level};
+    use inkwell::attributes::{Attribute, AttributeLoc};
+    use inkwell::context::Context;
+    use inkwell::module::Linkage;
+    use inkwell::targets::{CodeModel, FileType, RelocMode};
+    use std::time::SystemTime;
+
     use roc_reporting::report::{
         can_problem, mono_problem, type_problem, RocDocAllocator, DEFAULT_PALETTE,
     };
@@ -87,9 +96,6 @@ pub fn gen_from_mono_module(
     // module.strip_debug_info();
 
     // mark our zig-defined builtins as internal
-    use inkwell::attributes::{Attribute, AttributeLoc};
-    use inkwell::module::Linkage;
-
     let app_ll_file = {
         let mut temp = PathBuf::from(roc_file_path);
         temp.set_extension("ll");
@@ -226,7 +232,7 @@ pub fn gen_from_mono_module(
         let reloc = RelocMode::Default;
         let model = CodeModel::Default;
         let target_machine =
-            target::target_machine(&target, opt_level.into(), reloc, model).unwrap();
+            target::target_machine(&target, convert_opt_level(opt_level), reloc, model).unwrap();
 
         target_machine
             .write_to_file(&env.module, FileType::Object, &app_o_file)

compiler/build/src/target.rs

@@ -1,7 +1,10 @@
-use inkwell::targets::{
-    CodeModel, InitializationConfig, RelocMode, Target, TargetMachine, TargetTriple,
+#[cfg(feature = "llvm")]
+use inkwell::{
+    targets::{CodeModel, InitializationConfig, RelocMode, Target, TargetMachine, TargetTriple},
+    OptimizationLevel,
 };
-use inkwell::OptimizationLevel;
+#[cfg(feature = "llvm")]
+use roc_mono::ir::OptLevel;
 use target_lexicon::{Architecture, OperatingSystem, Triple};
 
 pub fn target_triple_str(target: &Triple) -> &'static str {
@@ -28,36 +31,20 @@ pub fn target_triple_str(target: &Triple) -> &'static str {
     }
 }
 
-/// 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
+#[cfg(feature = "llvm")]
+pub fn init_arch(target: &Triple) {
     match target.architecture {
         Architecture::X86_64 => {
             Target::initialize_x86(&InitializationConfig::default());
-
-            "x86-64"
         }
         Architecture::Aarch64(_) if cfg!(feature = "target-aarch64") => {
             Target::initialize_aarch64(&InitializationConfig::default());
-            "aarch64"
         }
         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: {:?}",
@@ -66,6 +53,26 @@ pub fn arch_str(target: &Triple) -> &'static str {
     }
 }
 
+/// 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 => "x86-64",
+        Architecture::Aarch64(_) if cfg!(feature = "target-aarch64") => "aarch64",
+        Architecture::Arm(_) if cfg!(feature = "target-arm") => "arm",
+        Architecture::Wasm32 if cfg!(feature = "target-webassembly") => "wasm32",
+        _ => panic!(
+            "TODO gracefully handle unsupported target architecture: {:?}",
+            target.architecture
+        ),
+    }
+}
+
+#[cfg(feature = "llvm")]
 pub fn target_machine(
     target: &Triple,
     opt: OptimizationLevel,
@@ -83,3 +90,11 @@ pub fn target_machine(
         model,
     )
 }
+
+#[cfg(feature = "llvm")]
+pub fn convert_opt_level(level: OptLevel) -> OptimizationLevel {
+    match level {
+        OptLevel::Normal => OptimizationLevel::None,
+        OptLevel::Optimize => OptimizationLevel::Aggressive,
+    }
+}

compiler/gen/src/llvm/build.rs

@@ -49,7 +49,8 @@ use roc_module::ident::TagName;
 use roc_module::low_level::LowLevel;
 use roc_module::symbol::{Interns, ModuleId, Symbol};
 use roc_mono::ir::{
-    BranchInfo, CallType, ExceptionId, JoinPointId, ModifyRc, TopLevelFunctionLayout, Wrapped,
+    BranchInfo, CallType, ExceptionId, JoinPointId, ModifyRc, OptLevel, TopLevelFunctionLayout,
+    Wrapped,
 };
 use roc_mono::layout::{Builtin, InPlace, LambdaSet, Layout, LayoutIds, UnionLayout};
 use target_lexicon::CallingConvention;
@@ -86,21 +87,6 @@ macro_rules! debug_info_init {
     }};
 }
 
-#[derive(Debug, Clone, Copy)]
-pub enum OptLevel {
-    Normal,
-    Optimize,
-}
-
-impl From<OptLevel> for OptimizationLevel {
-    fn from(level: OptLevel) -> Self {
-        match level {
-            OptLevel::Normal => OptimizationLevel::None,
-            OptLevel::Optimize => OptimizationLevel::Aggressive,
-        }
-    }
-}
-
 /// Iterate over all functions in an llvm module
 pub struct FunctionIterator<'ctx> {
     next: Option<FunctionValue<'ctx>>,

compiler/mono/src/ir.rs

@@ -43,6 +43,12 @@ macro_rules! return_on_layout_error {
     };
 }
 
+#[derive(Debug, Clone, Copy)]
+pub enum OptLevel {
+    Normal,
+    Optimize,
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum MonoProblem {
     PatternProblem(crate::exhaustive::Error),

compiler/test_gen/src/helpers/eval.rs

@@ -6,6 +6,7 @@ use roc_can::def::Def;
 use roc_collections::all::{MutMap, MutSet};
 use roc_gen::llvm::externs::add_default_roc_externs;
 use roc_module::symbol::Symbol;
+use roc_mono::ir::OptLevel;
 use roc_types::subs::VarStore;
 
 fn promote_expr_to_module(src: &str) -> String {
@@ -190,9 +191,9 @@ pub fn helper<'a>(
     module.strip_debug_info();
 
     let opt_level = if cfg!(debug_assertions) {
-        roc_gen::llvm::build::OptLevel::Normal
+        OptLevel::Normal
     } else {
-        roc_gen::llvm::build::OptLevel::Optimize
+        OptLevel::Optimize
     };
 
     let module = arena.alloc(module);