Remove (direct) rustc_llvm dependency from rustc_driver

This does not actually improve build times, since it still depends
on rustc_trans, but is better layering and fits the multi-backend
future slightly better.

src/Cargo.lock

@@ -560,7 +560,6 @@ dependencies = [
  "rustc_errors 0.0.0",
  "rustc_incremental 0.0.0",
  "rustc_lint 0.0.0",
- "rustc_llvm 0.0.0",
  "rustc_metadata 0.0.0",
  "rustc_mir 0.0.0",
  "rustc_passes 0.0.0",

src/librustc/session/config.rs

@@ -328,7 +328,7 @@ top_level_options!(
     }
 );
 
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub enum PrintRequest {
     FileNames,
     Sysroot,

src/librustc_driver/Cargo.toml

@@ -22,7 +22,6 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_incremental = { path = "../librustc_incremental" }
 rustc_lint = { path = "../librustc_lint" }
-rustc_llvm = { path = "../librustc_llvm" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
 rustc_passes = { path = "../librustc_passes" }

src/librustc_driver/lib.rs

@@ -56,7 +56,6 @@ extern crate rustc_save_analysis;
 extern crate rustc_trans;
 extern crate rustc_typeck;
 extern crate serialize;
-extern crate rustc_llvm as llvm;
 #[macro_use]
 extern crate log;
 extern crate syntax;
@@ -70,7 +69,7 @@ use rustc_resolve as resolve;
 use rustc_save_analysis as save;
 use rustc_save_analysis::DumpHandler;
 use rustc_trans::back::link;
-use rustc_trans::back::write::{create_target_machine, RELOC_MODEL_ARGS, CODE_GEN_MODEL_ARGS};
+use rustc_trans::back::write::{RELOC_MODEL_ARGS, CODE_GEN_MODEL_ARGS};
 use rustc::dep_graph::DepGraph;
 use rustc::session::{self, config, Session, build_session, CompileResult};
 use rustc::session::config::{Input, PrintRequest, OutputType, ErrorOutputType};
@@ -182,7 +181,7 @@ pub fn run_compiler<'a>(args: &[String],
     let (sopts, cfg) = config::build_session_options_and_crate_config(&matches);
 
     if sopts.debugging_opts.debug_llvm {
-        unsafe { llvm::LLVMRustSetDebug(1); }
+        rustc_trans::enable_llvm_debug();
     }
 
     let descriptions = diagnostics_registry();
@@ -671,14 +670,6 @@ impl RustcDefaultCalls {
                         println!("{}", cfg);
                     }
                 }
-                PrintRequest::TargetCPUs => {
-                    let tm = create_target_machine(sess);
-                    unsafe { llvm::LLVMRustPrintTargetCPUs(tm); }
-                }
-                PrintRequest::TargetFeatures => {
-                    let tm = create_target_machine(sess);
-                    unsafe { llvm::LLVMRustPrintTargetFeatures(tm); }
-                }
                 PrintRequest::RelocationModels => {
                     println!("Available relocation models:");
                     for &(name, _) in RELOC_MODEL_ARGS.iter() {
@@ -693,6 +684,9 @@ impl RustcDefaultCalls {
                     }
                     println!("");
                 }
+                PrintRequest::TargetCPUs | PrintRequest::TargetFeatures => {
+                    rustc_trans::print(*req, sess);
+                }
             }
         }
         return Compilation::Stop;
@@ -730,10 +724,7 @@ pub fn version(binary: &str, matches: &getopts::Matches) {
         println!("commit-date: {}", unw(commit_date_str()));
         println!("host: {}", config::host_triple());
         println!("release: {}", unw(release_str()));
-        unsafe {
-            println!("LLVM version: {}.{}",
-                     llvm::LLVMRustVersionMajor(), llvm::LLVMRustVersionMinor());
-        }
+        rustc_trans::print_version();
     }
 }
 
@@ -1026,9 +1017,7 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     }
 
     if cg_flags.contains(&"passes=list".to_string()) {
-        unsafe {
-            ::llvm::LLVMRustPrintPasses();
-        }
+        rustc_trans::print_passes();
         return None;
     }
 

src/librustc_driver/target_features.rs

@@ -9,24 +9,9 @@
 // except according to those terms.
 
 use syntax::ast;
-use llvm::LLVMRustHasFeature;
 use rustc::session::Session;
-use rustc_trans::back::write::create_target_machine;
 use syntax::symbol::Symbol;
-use libc::c_char;
-
-// WARNING: the features must be known to LLVM or the feature
-// detection code will walk past the end of the feature array,
-// leading to crashes.
-
-const ARM_WHITELIST: &'static [&'static str] = &["neon\0", "vfp2\0", "vfp3\0", "vfp4\0"];
-
-const X86_WHITELIST: &'static [&'static str] = &["avx\0", "avx2\0", "bmi\0", "bmi2\0", "sse\0",
-                                                 "sse2\0", "sse3\0", "sse4.1\0", "sse4.2\0",
-                                                 "ssse3\0", "tbm\0", "lzcnt\0", "popcnt\0",
-                                                 "sse4a\0", "rdrnd\0", "rdseed\0", "fma\0"];
-
-const HEXAGON_WHITELIST: &'static [&'static str] = &["hvx\0", "hvx-double\0"];
+use rustc_trans;
 
 /// Add `target_feature = "..."` cfgs for a variety of platform
 /// specific features (SSE, NEON etc.).
@@ -34,21 +19,10 @@ const HEXAGON_WHITELIST: &'static [&'static str] = &["hvx\0", "hvx-double\0"];
 /// This is performed by checking whether a whitelisted set of
 /// features is available on the target machine, by querying LLVM.
 pub fn add_configuration(cfg: &mut ast::CrateConfig, sess: &Session) {
-    let target_machine = create_target_machine(sess);
-
-    let whitelist = match &*sess.target.target.arch {
-        "arm" => ARM_WHITELIST,
-        "x86" | "x86_64" => X86_WHITELIST,
-        "hexagon" => HEXAGON_WHITELIST,
-        _ => &[],
-    };
-
     let tf = Symbol::intern("target_feature");
-    for feat in whitelist {
-        assert_eq!(feat.chars().last(), Some('\0'));
-        if unsafe { LLVMRustHasFeature(target_machine, feat.as_ptr() as *const c_char) } {
-            cfg.insert((tf, Some(Symbol::intern(&feat[..feat.len() - 1]))));
-        }
+
+    for feat in rustc_trans::target_features(sess) {
+        cfg.insert((tf, Some(feat)));
     }
 
     let requested_features = sess.opts.cg.target_feature.split(',');

src/librustc_trans/lib.rs

@@ -72,6 +72,7 @@ pub use base::trans_crate;
 pub use back::symbol_names::provide;
 
 pub use metadata::LlvmMetadataLoader;
+pub use llvm_util::{init, target_features, print_version, print_passes, print, enable_llvm_debug};
 
 pub mod back {
     pub use rustc::hir::svh;
@@ -122,6 +123,7 @@ mod debuginfo;
 mod declare;
 mod glue;
 mod intrinsic;
+mod llvm_util;
 mod machine;
 mod metadata;
 mod meth;
@@ -178,55 +180,3 @@ pub struct CrateTranslation {
 }
 
 __build_diagnostic_array! { librustc_trans, DIAGNOSTICS }
-
-use rustc::session::Session;
-pub fn init(sess: &Session) {
-    unsafe {
-        // Before we touch LLVM, make sure that multithreading is enabled.
-        use std::sync::Once;
-        static INIT: Once = Once::new();
-        static mut POISONED: bool = false;
-        INIT.call_once(|| {
-            if llvm::LLVMStartMultithreaded() != 1 {
-                // use an extra bool to make sure that all future usage of LLVM
-                // cannot proceed despite the Once not running more than once.
-                POISONED = true;
-            }
-
-            configure_llvm(sess);
-        });
-
-        if POISONED {
-            bug!("couldn't enable multi-threaded LLVM");
-        }
-    }
-}
-
-use std::ffi::CString;
-use libc::c_int;
-unsafe fn configure_llvm(sess: &Session) {
-    let mut llvm_c_strs = Vec::new();
-    let mut llvm_args = Vec::new();
-
-    {
-        let mut add = |arg: &str| {
-            let s = CString::new(arg).unwrap();
-            llvm_args.push(s.as_ptr());
-            llvm_c_strs.push(s);
-        };
-        add("rustc"); // fake program name
-        if sess.time_llvm_passes() { add("-time-passes"); }
-        if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
-
-        for arg in &sess.opts.cg.llvm_args {
-            add(&(*arg));
-        }
-    }
-
-    llvm::LLVMInitializePasses();
-
-    llvm::initialize_available_targets();
-
-    llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
-                                 llvm_args.as_ptr());
-}

src/librustc_trans/llvm_util.rs

@@ -0,0 +1,125 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use syntax_pos::symbol::Symbol;
+use back::write::create_target_machine;
+use llvm;
+use rustc::session::Session;
+use rustc::session::config::PrintRequest;
+use libc::{c_int, c_char};
+use std::ffi::CString;
+
+pub fn init(sess: &Session) {
+    unsafe {
+        // Before we touch LLVM, make sure that multithreading is enabled.
+        use std::sync::Once;
+        static INIT: Once = Once::new();
+        static mut POISONED: bool = false;
+        INIT.call_once(|| {
+            if llvm::LLVMStartMultithreaded() != 1 {
+                // use an extra bool to make sure that all future usage of LLVM
+                // cannot proceed despite the Once not running more than once.
+                POISONED = true;
+            }
+
+            configure_llvm(sess);
+        });
+
+        if POISONED {
+            bug!("couldn't enable multi-threaded LLVM");
+        }
+    }
+}
+
+unsafe fn configure_llvm(sess: &Session) {
+    let mut llvm_c_strs = Vec::new();
+    let mut llvm_args = Vec::new();
+
+    {
+        let mut add = |arg: &str| {
+            let s = CString::new(arg).unwrap();
+            llvm_args.push(s.as_ptr());
+            llvm_c_strs.push(s);
+        };
+        add("rustc"); // fake program name
+        if sess.time_llvm_passes() { add("-time-passes"); }
+        if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
+
+        for arg in &sess.opts.cg.llvm_args {
+            add(&(*arg));
+        }
+    }
+
+    llvm::LLVMInitializePasses();
+
+    llvm::initialize_available_targets();
+
+    llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
+                                 llvm_args.as_ptr());
+}
+
+// WARNING: the features must be known to LLVM or the feature
+// detection code will walk past the end of the feature array,
+// leading to crashes.
+
+const ARM_WHITELIST: &'static [&'static str] = &["neon\0", "vfp2\0", "vfp3\0", "vfp4\0"];
+
+const X86_WHITELIST: &'static [&'static str] = &["avx\0", "avx2\0", "bmi\0", "bmi2\0", "sse\0",
+                                                 "sse2\0", "sse3\0", "sse4.1\0", "sse4.2\0",
+                                                 "ssse3\0", "tbm\0", "lzcnt\0", "popcnt\0",
+                                                 "sse4a\0", "rdrnd\0", "rdseed\0", "fma\0"];
+
+const HEXAGON_WHITELIST: &'static [&'static str] = &["hvx\0", "hvx-double\0"];
+
+pub fn target_features(sess: &Session) -> Vec<Symbol> {
+    let target_machine = create_target_machine(sess);
+
+    let whitelist = match &*sess.target.target.arch {
+        "arm" => ARM_WHITELIST,
+        "x86" | "x86_64" => X86_WHITELIST,
+        "hexagon" => HEXAGON_WHITELIST,
+        _ => &[],
+    };
+
+    let mut features = Vec::new();
+    for feat in whitelist {
+        assert_eq!(feat.chars().last(), Some('\0'));
+        if unsafe { llvm::LLVMRustHasFeature(target_machine, feat.as_ptr() as *const c_char) } {
+            features.push(Symbol::intern(&feat[..feat.len() - 1]));
+        }
+    }
+    features
+}
+
+pub fn print_version() {
+    unsafe {
+        println!("LLVM version: {}.{}",
+                 llvm::LLVMRustVersionMajor(), llvm::LLVMRustVersionMinor());
+    }
+}
+
+pub fn print_passes() {
+    unsafe { llvm::LLVMRustPrintPasses(); }
+}
+
+pub fn print(req: PrintRequest, sess: &Session) {
+    let tm = create_target_machine(sess);
+    unsafe {
+        match req {
+            PrintRequest::TargetCPUs => llvm::LLVMRustPrintTargetCPUs(tm),
+            PrintRequest::TargetFeatures => llvm::LLVMRustPrintTargetFeatures(tm),
+            _ => bug!("rustc_trans can't handle print request: {:?}", req),
+        }
+    }
+}
+
+pub fn enable_llvm_debug() {
+    unsafe { llvm::LLVMRustSetDebug(1); }
+}