Auto merge of #39747 - mattico:fix-llvm4-createcompileunit, r=alexcrichton

[LLVM 4.0] Fix CreateCompileUnit

This is largely identical to @dylanmckay's [patch](https://github.com/dylanmckay), except that it doesn't try to use `file_metadata()`. I don't think that is necessary because we don't want the compile unit to be added to  `debug_context.created_files`, though I'd like confirmation from someone who knows for sure. If that is needed, I can modify `file_metadata_()` so that it can be used from `compile_unit_metadata()`.

1 files changed, 11 insertions, 3 deletions

diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 27233a8b075..40432735911 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -474,11 +474,19 @@ extern "C" void LLVMRustDIBuilderFinalize(LLVMRustDIBuilderRef Builder) {
 }
 
 extern "C" LLVMRustMetadataRef LLVMRustDIBuilderCreateCompileUnit(
-    LLVMRustDIBuilderRef Builder, unsigned Lang, const char *File,
-    const char *Dir, const char *Producer, bool isOptimized, const char *Flags,
+    LLVMRustDIBuilderRef Builder, unsigned Lang, LLVMRustMetadataRef FileRef,
+    const char *Producer, bool isOptimized, const char *Flags,
     unsigned RuntimeVer, const char *SplitName) {
-  return wrap(Builder->createCompileUnit(Lang, File, Dir, Producer, isOptimized,
+  auto *File = unwrapDI<DIFile>(FileRef);
+
+#if LLVM_VERSION_GE(4, 0)
+  return wrap(Builder->createCompileUnit(Lang, File, Producer, isOptimized,
                                          Flags, RuntimeVer, SplitName));
+#else
+  return wrap(Builder->createCompileUnit(Lang, File->getFilename(),
+      File->getDirectory(), Producer, isOptimized,
+      Flags, RuntimeVer, SplitName));
+#endif
 }
 
 extern "C" LLVMRustMetadataRef