Introduce the `init_llvm` function

Extract the code that performs the initialization of the LLVM backend
and invoke it before computing the available features. The
initialization is required to happen before the features are added to
the configuration, because they are computed by LLVM, therefore is is
now performed when creating the `Session` object.

diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index d3005ff2ded251e4c68ea560d36febb8f16f953a..dfde3ded46d17ed58032ba159ffd755f03e453ec 100644 (file)
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -30,13 +30,16 @@
 use syntax::feature_gate::AttributeType;
 
 use rustc_back::target::Target;
+use llvm;
 
 use std::path::{Path, PathBuf};
 use std::cell::{Cell, RefCell};
 use std::collections::{HashMap, HashSet};
 use std::env;
+use std::ffi::CString;
 use std::rc::Rc;
 use std::fmt;
+use libc::c_int;
 
 pub mod config;
 pub mod filesearch;
@@ -491,9 +494,63 @@ pub fn build_session_(sopts: config::Options,
         imported_macro_spans: RefCell::new(HashMap::new()),
     };
 
+    init_llvm(&sess);
+
     sess
 }
 
+fn init_llvm(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"); }
+
+        // FIXME #21627 disable faulty FastISel on AArch64 (even for -O0)
+        if sess.target.target.arch == "aarch64" { add("-fast-isel=0"); }
+
+        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());
+}
+
 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
     let mut emitter: Box<Emitter> = match output {
         config::ErrorOutputType::HumanReadable(color_config) => {

diff --git a/src/librustc_trans/back/write.rs b/src/librustc_trans/back/write.rs
index e6a51eb7c87e994a2f86398f40bff8c54f0f1e76..8a915f044053a440138b70a16f3da605dc10de14 100644 (file)
--- a/src/librustc_trans/back/write.rs
+++ b/src/librustc_trans/back/write.rs
@@ -31,7 +31,7 @@
 use std::sync::{Arc, Mutex};
 use std::sync::mpsc::channel;
 use std::thread;
-use libc::{c_uint, c_int, c_void};
+use libc::{c_uint, c_void};
 
 pub fn llvm_err(handler: &errors::Handler, msg: String) -> ! {
     match llvm::last_error() {
@@ -984,36 +984,6 @@ pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
     }
 }
 
-pub 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"); }
-
-        // FIXME #21627 disable faulty FastISel on AArch64 (even for -O0)
-        if sess.target.target.arch == "aarch64" { add("-fast-isel=0"); }
-
-        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());
-}
-
 pub unsafe fn with_llvm_pmb(llmod: ModuleRef,
                             config: &ModuleConfig,
                             f: &mut FnMut(llvm::PassManagerBuilderRef)) {

diff --git a/src/librustc_trans/base.rs b/src/librustc_trans/base.rs
index 17230eff6e639aa382f89c98d252a7a99950a83e..6304a0eacd3b562aca7e6a7198f3dbbb272d6643 100644 (file)
--- a/src/librustc_trans/base.rs
+++ b/src/librustc_trans/base.rs
@@ -2709,26 +2709,6 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
         tcx.sess.opts.debug_assertions
     };
 
-    // Before we touch LLVM, make sure that multithreading is enabled.
-    unsafe {
-        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;
-            }
-
-            ::back::write::configure_llvm(&tcx.sess);
-        });
-
-        if POISONED {
-            bug!("couldn't enable multi-threaded LLVM");
-        }
-    }
-
     let link_meta = link::build_link_meta(&tcx, name);
 
     let codegen_units = tcx.sess.opts.cg.codegen_units;