diff --git a/deps/Makefile b/deps/Makefile
index 0ecca17fd10313..4fc3ce6fc632cb 100644
--- a/deps/Makefile
+++ b/deps/Makefile
@@ -414,7 +414,7 @@ LLVM_FLAGS += --enable-libcpp
 endif # USE_LIBCPP
 ifeq ($(OS), WINNT)
 LLVM_FLAGS += --with-extra-ld-options="-Wl,--stack,8388608" LDFLAGS=""
-LLVM_CPPFLAGS += -D__USING_SJLJ_EXCEPTIONS__ -D__CRT__NO_INLINE
+LLVM_CPPFLAGS += -D__USING_SJLJ_EXCEPTIONS__ -D__CRT__NO_INLINE -DMINGW_HAS_SECURE_API=1
 ifneq ($(BUILD_OS),WINNT)
 LLVM_CMAKE += -DCROSS_TOOLCHAIN_FLAGS_NATIVE=-DCMAKE_TOOLCHAIN_FILE=$(SRCDIR)/NATIVE.cmake
 endif # BUILD_OS != WINNT
@@ -720,6 +720,12 @@ $(eval $(call LLVM_PATCH,llvm-3.7.1_2))
 $(eval $(call LLVM_PATCH,llvm-3.7.1_3))
 $(eval $(call LLVM_PATCH,llvm-D14260))
 $(LLVM_SRC_DIR)/llvm-3.7.1_2.patch-applied: $(LLVM_SRC_DIR)/llvm-3.7.1.patch-applied
+else ifeq ($(LLVM_VER),3.8.0)
+$(eval $(call LLVM_PATCH,llvm-3.7.1_3))
+$(eval $(call LLVM_PATCH,llvm-D14260))
+$(eval $(call LLVM_PATCH,llvm-3.8.0_winshlib))
+# Cygwin and openSUSE still use win32-threads mingw, https://llvm.org/bugs/show_bug.cgi?id=26365
+$(eval $(call LLVM_PATCH,llvm-3.8.0_threads))
 endif # LLVM_VER
 
 ifeq ($(LLVM_VER),3.7.1)
diff --git a/deps/checksums/llvm-3.8.0.src.tar.xz/md5 b/deps/checksums/llvm-3.8.0.src.tar.xz/md5
new file mode 100644
index 00000000000000..d0d99639e9c9d5
--- /dev/null
+++ b/deps/checksums/llvm-3.8.0.src.tar.xz/md5
@@ -0,0 +1 @@
+07a7a74f3c6bd65de4702bf941b511a0
diff --git a/deps/checksums/llvm-3.8.0.src.tar.xz/sha512 b/deps/checksums/llvm-3.8.0.src.tar.xz/sha512
new file mode 100644
index 00000000000000..afe5665688e856
--- /dev/null
+++ b/deps/checksums/llvm-3.8.0.src.tar.xz/sha512
@@ -0,0 +1 @@
+2c76e79d803768ed20af6ca1801cf2518071bf9835c54580ea3eb6219a66cdcf8b4c575f192c15082cc18d2468b7611dacb57950b605813a2317125c2d33c138
diff --git a/deps/llvm-3.8.0_threads.patch b/deps/llvm-3.8.0_threads.patch
new file mode 100644
index 00000000000000..7a6db986e66699
--- /dev/null
+++ b/deps/llvm-3.8.0_threads.patch
@@ -0,0 +1,165 @@
+From 69ef168544e4f15b793dd35d272008fde9a6e835 Mon Sep 17 00:00:00 2001
+From: Alex Crichton <alex@alexcrichton.com>
+Date: Thu, 28 Jan 2016 20:44:50 -0800
+Subject: [PATCH] Don't compile usage of std::thread
+
+As of the time of this writing it's not actually used anywhere meaningfullly
+throughout the LLVM repo that we need, and it unfortunately uses `std::thread`
+which isn't available in mingw-w64 toolchains with the win32 threading model
+(the one that we use).
+
+Two major changes were made to achieve this:
+
+1. The `ThreadPool.cpp` file was just entirely commented out. This isn't used
+   anywhere in the LLVM repo nor in Rust itself.
+2. The `ParallelCG.cpp` file was mostly deleted. Unfortunately it's used a few
+   places in LLVM and is needed to link correctly, but we in Rust don't use it
+   at all. For now it's just a stub implementation that hopefully compiles
+   everywhere, but perhaps we can find a less invasive (aka doesn't have rebase
+   conflicts in the future) change to apply soon.
+
+For reference, the upstream LLVM bug has been reported [1]
+
+[1]: https://llvm.org/bugs/show_bug.cgi?id=26365
+---
+ include/llvm/Support/ThreadPool.h |  4 +++
+ include/llvm/Support/thread.h     |  4 +++
+ lib/CodeGen/ParallelCG.cpp        | 63 +--------------------------------------
+ lib/Support/ThreadPool.cpp        |  4 +++
+ 4 files changed, 13 insertions(+), 62 deletions(-)
+
+diff --git a/include/llvm/Support/ThreadPool.h b/include/llvm/Support/ThreadPool.h
+index 745334d..4564615 100644
+--- a/include/llvm/Support/ThreadPool.h
++++ b/include/llvm/Support/ThreadPool.h
+@@ -11,6 +11,8 @@
+ //
+ //===----------------------------------------------------------------------===//
+ 
++#if 0
++
+ #ifndef LLVM_SUPPORT_THREAD_POOL_H
+ #define LLVM_SUPPORT_THREAD_POOL_H
+ 
+@@ -134,3 +136,5 @@ class ThreadPool {
+ }
+ 
+ #endif // LLVM_SUPPORT_THREAD_POOL_H
++
++#endif
+diff --git a/include/llvm/Support/thread.h b/include/llvm/Support/thread.h
+index 2d13041..80340e6 100644
+--- a/include/llvm/Support/thread.h
++++ b/include/llvm/Support/thread.h
+@@ -14,6 +14,8 @@
+ //
+ //===----------------------------------------------------------------------===//
+ 
++#if 0
++
+ #ifndef LLVM_SUPPORT_THREAD_H
+ #define LLVM_SUPPORT_THREAD_H
+ 
+@@ -64,3 +66,5 @@ struct thread {
+ #endif // LLVM_ENABLE_THREADS
+ 
+ #endif
++
++#endif
+diff --git a/lib/CodeGen/ParallelCG.cpp b/lib/CodeGen/ParallelCG.cpp
+index e73ba02..7362cda 100644
+--- a/lib/CodeGen/ParallelCG.cpp
++++ b/lib/CodeGen/ParallelCG.cpp
+@@ -25,72 +25,11 @@
+ 
+ using namespace llvm;
+ 
+-static void codegen(Module *M, llvm::raw_pwrite_stream &OS,
+-                    const Target *TheTarget, StringRef CPU, StringRef Features,
+-                    const TargetOptions &Options, Reloc::Model RM,
+-                    CodeModel::Model CM, CodeGenOpt::Level OL,
+-                    TargetMachine::CodeGenFileType FileType) {
+-  std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
+-      M->getTargetTriple(), CPU, Features, Options, RM, CM, OL));
+-
+-  legacy::PassManager CodeGenPasses;
+-  if (TM->addPassesToEmitFile(CodeGenPasses, OS, FileType))
+-    report_fatal_error("Failed to setup codegen");
+-  CodeGenPasses.run(*M);
+-}
+-
+ std::unique_ptr<Module>
+ llvm::splitCodeGen(std::unique_ptr<Module> M,
+                    ArrayRef<llvm::raw_pwrite_stream *> OSs, StringRef CPU,
+                    StringRef Features, const TargetOptions &Options,
+                    Reloc::Model RM, CodeModel::Model CM, CodeGenOpt::Level OL,
+                    TargetMachine::CodeGenFileType FileType) {
+-  StringRef TripleStr = M->getTargetTriple();
+-  std::string ErrMsg;
+-  const Target *TheTarget = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
+-  if (!TheTarget)
+-    report_fatal_error(Twine("Target not found: ") + ErrMsg);
+-
+-  if (OSs.size() == 1) {
+-    codegen(M.get(), *OSs[0], TheTarget, CPU, Features, Options, RM, CM,
+-            OL, FileType);
+-    return M;
+-  }
+-
+-  std::vector<thread> Threads;
+-  SplitModule(std::move(M), OSs.size(), [&](std::unique_ptr<Module> MPart) {
+-    // We want to clone the module in a new context to multi-thread the codegen.
+-    // We do it by serializing partition modules to bitcode (while still on the
+-    // main thread, in order to avoid data races) and spinning up new threads
+-    // which deserialize the partitions into separate contexts.
+-    // FIXME: Provide a more direct way to do this in LLVM.
+-    SmallVector<char, 0> BC;
+-    raw_svector_ostream BCOS(BC);
+-    WriteBitcodeToFile(MPart.get(), BCOS);
+-
+-    llvm::raw_pwrite_stream *ThreadOS = OSs[Threads.size()];
+-    Threads.emplace_back(
+-        [TheTarget, CPU, Features, Options, RM, CM, OL, FileType,
+-         ThreadOS](const SmallVector<char, 0> &BC) {
+-          LLVMContext Ctx;
+-          ErrorOr<std::unique_ptr<Module>> MOrErr =
+-              parseBitcodeFile(MemoryBufferRef(StringRef(BC.data(), BC.size()),
+-                                               "<split-module>"),
+-                               Ctx);
+-          if (!MOrErr)
+-            report_fatal_error("Failed to read bitcode");
+-          std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
+-
+-          codegen(MPartInCtx.get(), *ThreadOS, TheTarget, CPU, Features,
+-                  Options, RM, CM, OL, FileType);
+-        },
+-        // Pass BC using std::move to ensure that it get moved rather than
+-        // copied into the thread's context.
+-        std::move(BC));
+-  });
+-
+-  for (thread &T : Threads)
+-    T.join();
+-
+-  return {};
++  return M;
+ }
+diff --git a/lib/Support/ThreadPool.cpp b/lib/Support/ThreadPool.cpp
+index d4dcb2e..bc25c59 100644
+--- a/lib/Support/ThreadPool.cpp
++++ b/lib/Support/ThreadPool.cpp
+@@ -11,6 +11,8 @@
+ //
+ //===----------------------------------------------------------------------===//
+ 
++#if 0
++
+ #include "llvm/Support/ThreadPool.h"
+ 
+ #include "llvm/Config/llvm-config.h"
+@@ -153,3 +155,5 @@ ThreadPool::~ThreadPool() {
+ }
+ 
+ #endif
++
++#endif
diff --git a/deps/llvm-3.8.0_winshlib.patch b/deps/llvm-3.8.0_winshlib.patch
new file mode 100644
index 00000000000000..5aea42869827fd
--- /dev/null
+++ b/deps/llvm-3.8.0_winshlib.patch
@@ -0,0 +1,26 @@
+diff --git a/tools/llvm-shlib/Makefile b/tools/llvm-shlib/Makefile
+index 2bc81da..4ff211d 100644
+--- a/tools/llvm-shlib/Makefile
++++ b/tools/llvm-shlib/Makefile
+@@ -86,11 +86,19 @@ $(LibName.SO): $(SHLIB_STUBS)
+ 	$(Echo) Collecting global symbols of $(notdir $*)
+ 	$(Verb) $(NM_PATH) -g $< > $@
+ 
++# The Windows ABI specifies leading underscores only on 32bit, so
++# make sure we don't strip them on x86_64
++ifeq ($(ARCH),x86_64)
++ABI_UNDERSCORE =
++else
++ABI_UNDERSCORE =_
++endif
++
+ $(ObjDir)/$(LIBRARYNAME).exports: $(SHLIB_FRAGS) $(ObjDir)/.dir
+ 	$(Echo) Generating exports for $(LIBRARYNAME)
+ 	$(Verb) ($(SED) -n \
+-			-e "s/^.* T _\([^.][^.]*\)$$/\1/p" \
+-			-e "s/^.* [BDR] _\([^.][^.]*\)$$/\1 DATA/p" \
++			-e "s/^.* T $(ABI_UNDERSCORE)\([^.][^.]*\)$$/\1/p" \
++			-e "s/^.* [BDR] $(ABI_UNDERSCORE)\([^.][^.]*\)$$/\1 DATA/p" \
+ 			$(SHLIB_FRAGS) \
+ 		 | sort -u) > $@
+