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.

1 files changed, 34 insertions, 35 deletions

diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 4ee5df28d24..ba87624e2dd 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -329,12 +329,10 @@ LLVMRustLoadCrate(void* mem, const char* crate) {
   return true;
 }
 
-extern "C" void*
-LLVMRustExecuteJIT(void* mem,
-                   LLVMPassManagerRef PMR,
-                   LLVMModuleRef M,
-                   CodeGenOpt::Level OptLevel,
-                   bool EnableSegmentedStacks) {
+extern "C" LLVMExecutionEngineRef
+LLVMRustBuildJIT(void* mem,
+                 LLVMModuleRef M,
+                 bool EnableSegmentedStacks) {
 
   InitializeNativeTarget();
   InitializeNativeTargetAsmPrinter();
@@ -346,46 +344,28 @@ LLVMRustExecuteJIT(void* mem,
   Options.JITEmitDebugInfo = true;
   Options.NoFramePointerElim = true;
   Options.EnableSegmentedStacks = EnableSegmentedStacks;
-  PassManager *PM = unwrap<PassManager>(PMR);
   RustMCJITMemoryManager* MM = (RustMCJITMemoryManager*) mem;
-
   assert(MM);
 
-  PM->add(createBasicAliasAnalysisPass());
-  PM->add(createInstructionCombiningPass());
-  PM->add(createReassociatePass());
-  PM->add(createGVNPass());
-  PM->add(createCFGSimplificationPass());
-  PM->add(createFunctionInliningPass());
-  PM->add(createPromoteMemoryToRegisterPass());
-  PM->run(*unwrap(M));
-
   ExecutionEngine* EE = EngineBuilder(unwrap(M))
     .setErrorStr(&Err)
     .setTargetOptions(Options)
     .setJITMemoryManager(MM)
-    .setOptLevel(OptLevel)
     .setUseMCJIT(true)
     .setAllocateGVsWithCode(false)
     .create();
 
   if(!EE || Err != "") {
     LLVMRustError = Err.c_str();
-    return 0;
+    // The EngineBuilder only takes ownership of these two structures if the
+    // create() call is successful, but here it wasn't successful.
+    LLVMDisposeModule(M);
+    delete MM;
+    return NULL;
   }
 
   MM->invalidateInstructionCache();
-  Function* func = EE->FindFunctionNamed("_rust_main");
-
-  if(!func || Err != "") {
-    LLVMRustError = Err.c_str();
-    return 0;
-  }
-
-  void* entry = EE->getPointerToFunction(func);
-  assert(entry);
-
-  return entry;
+  return wrap(EE);
 }
 
 extern "C" bool
@@ -447,9 +427,10 @@ LLVMRustWriteOutputFile(LLVMPassManagerRef PMR,
   return true;
 }
 
-extern "C" LLVMModuleRef LLVMRustParseAssemblyFile(const char *Filename) {
+extern "C" LLVMModuleRef LLVMRustParseAssemblyFile(LLVMContextRef C,
+                                                   const char *Filename) {
   SMDiagnostic d;
-  Module *m = ParseAssemblyFile(Filename, d, getGlobalContext());
+  Module *m = ParseAssemblyFile(Filename, d, *unwrap(C));
   if (m) {
     return wrap(m);
   } else {
@@ -499,9 +480,6 @@ extern "C" LLVMValueRef LLVMGetOrInsertFunction(LLVMModuleRef M,
 extern "C" LLVMTypeRef LLVMMetadataTypeInContext(LLVMContextRef C) {
   return wrap(Type::getMetadataTy(*unwrap(C)));
 }
-extern "C" LLVMTypeRef LLVMMetadataType(void) {
-  return LLVMMetadataTypeInContext(LLVMGetGlobalContext());
-}
 
 extern "C" LLVMValueRef LLVMBuildAtomicLoad(LLVMBuilderRef B,
                                             LLVMValueRef source,
@@ -561,3 +539,24 @@ extern "C" LLVMValueRef LLVMInlineAsm(LLVMTypeRef Ty,
                                Constraints, HasSideEffects,
                                IsAlignStack, (InlineAsm::AsmDialect) Dialect));
 }
+
+/**
+ * This function is intended to be a threadsafe interface into enabling a
+ * multithreaded LLVM. This is invoked at the start of the translation phase of
+ * compilation to ensure that LLVM is ready.
+ *
+ * All of trans properly isolates LLVM with the use of a different
+ * LLVMContextRef per task, thus allowing parallel compilation of different
+ * crates in the same process. At the time of this writing, the use case for
+ * this is unit tests for rusti, but there are possible other applications.
+ */
+extern "C" bool LLVMRustStartMultithreading() {
+    static Mutex lock;
+    bool ret = true;
+    assert(lock.acquire());
+    if (!LLVMIsMultithreaded()) {
+        ret = LLVMStartMultithreaded();
+    }
+    assert(lock.release());
+    return ret;
+}