Rollup merge of #47710 - alexcrichton:llvm-6-compat, r=nikomatsakis

First round of LLVM 6.0.0 compatibility

This includes a number of commits for the first round of upgrading to LLVM 6. There are still [lingering bugs](https://github.com/rust-lang/rust/issues/47683) but I believe all of this will nonetheless be necessary!

3 files changed, 29 insertions, 14 deletions

diff --git a/src/rustllvm/ArchiveWrapper.cpp b/src/rustllvm/ArchiveWrapper.cpp
index b110013ceae..93157cd6819 100644
--- a/src/rustllvm/ArchiveWrapper.cpp
+++ b/src/rustllvm/ArchiveWrapper.cpp
@@ -42,7 +42,6 @@ struct RustArchiveIterator {
 enum class LLVMRustArchiveKind {
   Other,
   GNU,
-  MIPS64,
   BSD,
   COFF,
 };
@@ -51,8 +50,6 @@ static Archive::Kind fromRust(LLVMRustArchiveKind Kind) {
   switch (Kind) {
   case LLVMRustArchiveKind::GNU:
     return Archive::K_GNU;
-  case LLVMRustArchiveKind::MIPS64:
-    return Archive::K_MIPS64;
   case LLVMRustArchiveKind::BSD:
     return Archive::K_BSD;
   case LLVMRustArchiveKind::COFF:
@@ -235,9 +232,16 @@ LLVMRustWriteArchive(char *Dst, size_t NumMembers,
       Members.push_back(std::move(*MOrErr));
     }
   }
-  auto Pair = writeArchive(Dst, Members, WriteSymbtab, Kind, true, false);
-  if (!Pair.second)
+  auto Result = writeArchive(Dst, Members, WriteSymbtab, Kind, true, false);
+#if LLVM_VERSION_GE(6, 0)
+  if (!Result)
     return LLVMRustResult::Success;
-  LLVMRustSetLastError(Pair.second.message().c_str());
+  LLVMRustSetLastError(toString(std::move(Result)).c_str());
+#else
+  if (!Result.second)
+    return LLVMRustResult::Success;
+  LLVMRustSetLastError(Result.second.message().c_str());
+#endif
+
   return LLVMRustResult::Failure;
 }
diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index 54a73a04bfa..b2f1229891d 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -23,9 +23,15 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetSubtargetInfo.h"
 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
 
+#if LLVM_VERSION_GE(6, 0)
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/IR/IntrinsicInst.h"
+#else
+#include "llvm/Target/TargetSubtargetInfo.h"
+#endif
+
 #if LLVM_VERSION_GE(4, 0)
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/FunctionImport.h"
@@ -210,20 +216,15 @@ extern "C" bool LLVMRustHasFeature(LLVMTargetMachineRef TM,
 
 enum class LLVMRustCodeModel {
   Other,
-  Default,
-  JITDefault,
   Small,
   Kernel,
   Medium,
   Large,
+  None,
 };
 
 static CodeModel::Model fromRust(LLVMRustCodeModel Model) {
   switch (Model) {
-  case LLVMRustCodeModel::Default:
-    return CodeModel::Default;
-  case LLVMRustCodeModel::JITDefault:
-    return CodeModel::JITDefault;
   case LLVMRustCodeModel::Small:
     return CodeModel::Small;
   case LLVMRustCodeModel::Kernel:
@@ -360,7 +361,6 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     bool TrapUnreachable,
     bool Singlethread) {
 
-  auto CM = fromRust(RustCM);
   auto OptLevel = fromRust(RustOptLevel);
   auto RM = fromRust(RustReloc);
 
@@ -399,6 +399,13 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     Options.ThreadModel = ThreadModel::Single;
   }
 
+#if LLVM_VERSION_GE(6, 0)
+  Optional<CodeModel::Model> CM;
+#else
+  CodeModel::Model CM = CodeModel::Model::Default;
+#endif
+  if (RustCM != LLVMRustCodeModel::None)
+    CM = fromRust(RustCM);
   TargetMachine *TM = TheTarget->createTargetMachine(
       Trip.getTriple(), RealCPU, Feature, Options, RM, CM, OptLevel);
   return wrap(TM);
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 82aafb7c355..611d63f6a4d 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -315,7 +315,11 @@ extern "C" void LLVMRustRemoveFunctionAttributes(LLVMValueRef Fn,
 // enable fpmath flag UnsafeAlgebra
 extern "C" void LLVMRustSetHasUnsafeAlgebra(LLVMValueRef V) {
   if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
+#if LLVM_VERSION_GE(6, 0)
+    I->setFast(true);
+#else
     I->setHasUnsafeAlgebra(true);
+#endif
   }
 }