1 files changed, 116 insertions, 0 deletions
diff --git a/lib/CodeGen/CGCoroutine.cpp b/lib/CodeGen/CGCoroutine.cpp
new file mode 100644
index 0000000000000..2fdb1279ece97
--- /dev/null
+++ b/lib/CodeGen/CGCoroutine.cpp
@@ -0,0 +1,116 @@
+//===----- CGCoroutine.cpp - Emit LLVM Code for C++ coroutines ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with C++ code generation of coroutines.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "clang/AST/StmtCXX.h"
+
+using namespace clang;
+using namespace CodeGen;
+
+namespace clang {
+namespace CodeGen {
+
+struct CGCoroData {
+  // Stores the llvm.coro.id emitted in the function so that we can supply it
+  // as the first argument to coro.begin, coro.alloc and coro.free intrinsics.
+  // Note: llvm.coro.id returns a token that cannot be directly expressed in a
+  // builtin.
+  llvm::CallInst *CoroId = nullptr;
+  // If coro.id came from the builtin, remember the expression to give better
+  // diagnostic. If CoroIdExpr is nullptr, the coro.id was created by
+  // EmitCoroutineBody.
+  CallExpr const *CoroIdExpr = nullptr;
+};
+}
+}
+
+clang::CodeGen::CodeGenFunction::CGCoroInfo::CGCoroInfo() {}
+CodeGenFunction::CGCoroInfo::~CGCoroInfo() {}
+
+static void createCoroData(CodeGenFunction &CGF,
+                           CodeGenFunction::CGCoroInfo &CurCoro,
+                           llvm::CallInst *CoroId,
+                           CallExpr const *CoroIdExpr = nullptr) {
+  if (CurCoro.Data) {
+    if (CurCoro.Data->CoroIdExpr)
+      CGF.CGM.Error(CoroIdExpr->getLocStart(),
+                    "only one __builtin_coro_id can be used in a function");
+    else if (CoroIdExpr)
+      CGF.CGM.Error(CoroIdExpr->getLocStart(),
+                    "__builtin_coro_id shall not be used in a C++ coroutine");
+    else
+      llvm_unreachable("EmitCoroutineBodyStatement called twice?");
+
+    return;
+  }
+
+  CurCoro.Data = std::unique_ptr<CGCoroData>(new CGCoroData);
+  CurCoro.Data->CoroId = CoroId;
+  CurCoro.Data->CoroIdExpr = CoroIdExpr;
+}
+
+void CodeGenFunction::EmitCoroutineBody(const CoroutineBodyStmt &S) {
+  auto *NullPtr = llvm::ConstantPointerNull::get(Builder.getInt8PtrTy());
+  auto &TI = CGM.getContext().getTargetInfo();
+  unsigned NewAlign = TI.getNewAlign() / TI.getCharWidth();
+
+  auto *CoroId = Builder.CreateCall(
+      CGM.getIntrinsic(llvm::Intrinsic::coro_id),
+      {Builder.getInt32(NewAlign), NullPtr, NullPtr, NullPtr});
+  createCoroData(*this, CurCoro, CoroId);
+
+  EmitScalarExpr(S.getAllocate());
+  // FIXME: Emit the rest of the coroutine.
+  EmitStmt(S.getDeallocate());
+}
+
+// Emit coroutine intrinsic and patch up arguments of the token type.
+RValue CodeGenFunction::EmitCoroutineIntrinsic(const CallExpr *E,
+                                               unsigned int IID) {
+  SmallVector<llvm::Value *, 8> Args;
+  switch (IID) {
+  default:
+    break;
+  // The following three intrinsics take a token parameter referring to a token
+  // returned by earlier call to @llvm.coro.id. Since we cannot represent it in
+  // builtins, we patch it up here.
+  case llvm::Intrinsic::coro_alloc:
+  case llvm::Intrinsic::coro_begin:
+  case llvm::Intrinsic::coro_free: {
+    if (CurCoro.Data && CurCoro.Data->CoroId) {
+      Args.push_back(CurCoro.Data->CoroId);
+      break;
+    }
+    CGM.Error(E->getLocStart(), "this builtin expect that __builtin_coro_id has"
+                                " been used earlier in this function");
+    // Fallthrough to the next case to add TokenNone as the first argument.
+  }
+  // @llvm.coro.suspend takes a token parameter. Add token 'none' as the first
+  // argument.
+  case llvm::Intrinsic::coro_suspend:
+    Args.push_back(llvm::ConstantTokenNone::get(getLLVMContext()));
+    break;
+  }
+  for (auto &Arg : E->arguments())
+    Args.push_back(EmitScalarExpr(Arg));
+
+  llvm::Value *F = CGM.getIntrinsic(IID);
+  llvm::CallInst *Call = Builder.CreateCall(F, Args);
+
+  // If we see @llvm.coro.id remember it in the CoroData. We will update
+  // coro.alloc, coro.begin and coro.free intrinsics to refer to it.
+  if (IID == llvm::Intrinsic::coro_id) {
+    createCoroData(*this, CurCoro, Call, E);
+  }
+  return RValue::get(Call);
+}