auto merge of #7125 : alexcrichton/rust/rusti-issues, r=brson

This un-reverts the reverts of the rusti commits made awhile back. These were reverted for an LLVM failure in rustpkg. I believe that this is not a problem with these commits, but rather that rustc is being used in parallel for rustpkg tests (in-process). This is not working yet (almost! see #7011), so I serialized all the tests to run one after another.

@brson, I'm mainly just guessing as to the cause of the LLVM failures in rustpkg tests. I'm confident that running tests in parallel is more likely to be the problem than those commits I made.

Additionally, this fixes two recently reported issues with rusti.

Author: bors

src/librustc/back/link.rs

@@ -101,34 +101,21 @@ pub mod jit {
     use back::link::llvm_err;
     use driver::session::Session;
     use lib::llvm::llvm;
-    use lib::llvm::{ModuleRef, PassManagerRef};
+    use lib::llvm::{ModuleRef, ContextRef};
     use metadata::cstore;
 
     use core::cast;
-    use core::libc::c_int;
     use core::ptr;
     use core::str;
-
-    pub mod rusti {
-        #[nolink]
-        #[abi = "rust-intrinsic"]
-        pub extern "rust-intrinsic" {
-            pub fn morestack_addr() -> *();
-        }
-    }
-
-    pub struct Closure {
-        code: *(),
-        env: *(),
-    }
+    use core::sys;
+    use core::unstable::intrinsics;
 
     pub fn exec(sess: Session,
-                pm: PassManagerRef,
+                c: ContextRef,
                 m: ModuleRef,
-                opt: c_int,
                 stacks: bool) {
         unsafe {
-            let manager = llvm::LLVMRustPrepareJIT(rusti::morestack_addr());
+            let manager = llvm::LLVMRustPrepareJIT(intrinsics::morestack_addr());
 
             // We need to tell JIT where to resolve all linked
             // symbols from. The equivalent of -lstd, -lcore, etc.
@@ -152,26 +139,43 @@ pub mod jit {
                     });
             }
 
-            // The execute function will return a void pointer
-            // to the _rust_main function. We can do closure
-            // magic here to turn it straight into a callable rust
-            // closure. It will also cleanup the memory manager
-            // for us.
-
-            let entry = llvm::LLVMRustExecuteJIT(manager,
-                                                 pm, m, opt, stacks);
-
-            if ptr::is_null(entry) {
-                llvm_err(sess, ~"Could not JIT");
-            } else {
-                let closure = Closure {
-                    code: entry,
-                    env: ptr::null()
-                };
-                let func: &fn() = cast::transmute(closure);
+            // We custom-build a JIT execution engine via some rust wrappers
+            // first. This wrappers takes ownership of the module passed in.
+            let ee = llvm::LLVMRustBuildJIT(manager, m, stacks);
+            if ee.is_null() {
+                llvm::LLVMContextDispose(c);
+                llvm_err(sess, ~"Could not create the JIT");
+            }
 
-                func();
+            // Next, we need to get a handle on the _rust_main function by
+            // looking up it's corresponding ValueRef and then requesting that
+            // the execution engine compiles the function.
+            let fun = do str::as_c_str("_rust_main") |entry| {
+                llvm::LLVMGetNamedFunction(m, entry)
+            };
+            if fun.is_null() {
+                llvm::LLVMDisposeExecutionEngine(ee);
+                llvm::LLVMContextDispose(c);
+                llvm_err(sess, ~"Could not find _rust_main in the JIT");
             }
+
+            // Finally, once we have the pointer to the code, we can do some
+            // closure magic here to turn it straight into a callable rust
+            // closure
+            let code = llvm::LLVMGetPointerToGlobal(ee, fun);
+            assert!(!code.is_null());
+            let closure = sys::Closure {
+                code: code,
+                env: ptr::null()
+            };
+            let func: &fn() = cast::transmute(closure);
+            func();
+
+            // Sadly, there currently is no interface to re-use this execution
+            // engine, so it's disposed of here along with the context to
+            // prevent leaks.
+            llvm::LLVMDisposeExecutionEngine(ee);
+            llvm::LLVMContextDispose(c);
         }
     }
 }
@@ -188,6 +192,7 @@ pub mod write {
     use driver::session;
     use lib::llvm::llvm;
     use lib::llvm::{ModuleRef, mk_pass_manager, mk_target_data};
+    use lib::llvm::{ContextRef};
     use lib;
 
     use back::passes;
@@ -206,6 +211,7 @@ pub mod write {
     }
 
     pub fn run_passes(sess: Session,
+                      llcx: ContextRef,
                       llmod: ModuleRef,
                       output_type: output_type,
                       output: &Path) {
@@ -261,7 +267,17 @@ pub mod write {
             debug!("Running Module Optimization Pass");
             mpm.run(llmod);
 
-            if is_object_or_assembly_or_exe(output_type) || opts.jit {
+            if opts.jit {
+                // If we are using JIT, go ahead and create and execute the
+                // engine now.  JIT execution takes ownership of the module and
+                // context, so don't dispose and return.
+                jit::exec(sess, llcx, llmod, true);
+
+                if sess.time_llvm_passes() {
+                    llvm::LLVMRustPrintPassTimings();
+                }
+                return;
+            } else if is_object_or_assembly_or_exe(output_type) {
                 let LLVMOptNone       = 0 as c_int; // -O0
                 let LLVMOptLess       = 1 as c_int; // -O1
                 let LLVMOptDefault    = 2 as c_int; // -O2, -Os
@@ -274,20 +290,6 @@ pub mod write {
                   session::Aggressive => LLVMOptAggressive
                 };
 
-                if opts.jit {
-                    // If we are using JIT, go ahead and create and
-                    // execute the engine now.
-                    // JIT execution takes ownership of the module,
-                    // so don't dispose and return.
-
-                    jit::exec(sess, pm.llpm, llmod, CodeGenOptLevel, true);
-
-                    if sess.time_llvm_passes() {
-                        llvm::LLVMRustPrintPassTimings();
-                    }
-                    return;
-                }
-
                 let FileType;
                 if output_type == output_type_object ||
                        output_type == output_type_exe {
@@ -348,6 +350,7 @@ pub mod write {
                 // Clean up and return
 
                 llvm::LLVMDisposeModule(llmod);
+                llvm::LLVMContextDispose(llcx);
                 if sess.time_llvm_passes() {
                     llvm::LLVMRustPrintPassTimings();
                 }
@@ -366,6 +369,7 @@ pub mod write {
             }
 
             llvm::LLVMDisposeModule(llmod);
+            llvm::LLVMContextDispose(llcx);
             if sess.time_llvm_passes() { llvm::LLVMRustPrintPassTimings(); }
         }
     }

src/librustc/driver/driver.rs

@@ -215,7 +215,7 @@ pub fn compile_rest(sess: Session,
 
     let mut crate = crate_opt.unwrap();
 
-    let (llmod, link_meta) = {
+    let (llcx, llmod, link_meta) = {
     crate = time(time_passes, ~"intrinsic injection", ||
                  front::intrinsic_inject::inject_intrinsic(sess, crate));
 
@@ -338,14 +338,14 @@ pub fn compile_rest(sess: Session,
         let obj_filename = outputs.obj_filename.with_filetype("s");
 
         time(time_passes, ~"LLVM passes", ||
-            link::write::run_passes(sess, llmod, output_type,
-                            &obj_filename));
+            link::write::run_passes(sess, llcx, llmod, output_type,
+                                    &obj_filename));
 
         link::write::run_ndk(sess, &obj_filename, &outputs.obj_filename);
     } else {
         time(time_passes, ~"LLVM passes", ||
-            link::write::run_passes(sess, llmod, sess.opts.output_type,
-                                &outputs.obj_filename));
+            link::write::run_passes(sess, llcx, llmod, sess.opts.output_type,
+                                    &outputs.obj_filename));
     }
 
     let stop_after_codegen =