[CoroSplit][DebugInfo] Don't use entry_value in coroutine entry point

The entry point function is called as a regular function. Among other things, it
can be inlined, which would violate the semantics of entry_value in the IR.

Differential Revision: https://reviews.llvm.org/D158108

Author: felipepiovezan

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -1882,7 +1882,8 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
                              &*Builder.GetInsertPoint());
           // This dbg.declare is for the main function entry point.  It
           // will be deleted in all coro-split functions.
-          coro::salvageDebugInfo(ArgToAllocaMap, DDI, Shape.OptimizeFrame);
+          coro::salvageDebugInfo(ArgToAllocaMap, DDI, Shape.OptimizeFrame,
+                                 true /*IsEntryPoint*/);
         }
       }
 
@@ -2818,7 +2819,7 @@ static void collectFrameAlloca(AllocaInst *AI, coro::Shape &Shape,
 
 void coro::salvageDebugInfo(
     SmallDenseMap<Argument *, AllocaInst *, 4> &ArgToAllocaMap,
-    DbgVariableIntrinsic *DVI, bool OptimizeFrame) {
+    DbgVariableIntrinsic *DVI, bool OptimizeFrame, bool IsEntryPoint) {
   Function *F = DVI->getFunction();
   IRBuilder<> Builder(F->getContext());
   auto InsertPt = F->getEntryBlock().getFirstInsertionPt();
@@ -2870,7 +2871,10 @@ void coro::salvageDebugInfo(
 
   // Swift async arguments are described by an entry value of the ABI-defined
   // register containing the coroutine context.
-  if (IsSwiftAsyncArg && !Expr->isEntryValue())
+  // For the EntryPoint funclet, don't use EntryValues. This funclet can be
+  // inlined, which would remove the guarantee that this intrinsic targets an
+  // Argument.
+  if (IsSwiftAsyncArg && !IsEntryPoint && !Expr->isEntryValue())
     Expr = DIExpression::prepend(Expr, DIExpression::EntryValue);
 
   // If the coroutine frame is an Argument, store it in an alloca to improve

llvm/lib/Transforms/Coroutines/CoroInternal.h

@@ -32,7 +32,7 @@ void replaceCoroFree(CoroIdInst *CoroId, bool Elide);
 /// OptimizeFrame is false.
 void salvageDebugInfo(
     SmallDenseMap<Argument *, AllocaInst *, 4> &ArgToAllocaMap,
-    DbgVariableIntrinsic *DVI, bool OptimizeFrame);
+    DbgVariableIntrinsic *DVI, bool OptimizeFrame, bool IsEntryPoint);
 
 // Keeps data and helper functions for lowering coroutine intrinsics.
 struct LowererBase {

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -702,7 +702,8 @@ void CoroCloner::salvageDebugInfo() {
       collectDbgVariableIntrinsics(*NewF);
   SmallDenseMap<Argument *, AllocaInst *, 4> ArgToAllocaMap;
   for (DbgVariableIntrinsic *DVI : Worklist)
-    coro::salvageDebugInfo(ArgToAllocaMap, DVI, Shape.OptimizeFrame);
+    coro::salvageDebugInfo(ArgToAllocaMap, DVI, Shape.OptimizeFrame,
+                           false /*IsEntryPoint*/);
 
   // Remove all salvaged dbg.declare intrinsics that became
   // either unreachable or stale due to the CoroSplit transformation.
@@ -1995,7 +1996,8 @@ splitCoroutine(Function &F, SmallVectorImpl<Function *> &Clones,
   // coroutine funclets.
   SmallDenseMap<Argument *, AllocaInst *, 4> ArgToAllocaMap;
   for (auto *DDI : collectDbgVariableIntrinsics(F))
-    coro::salvageDebugInfo(ArgToAllocaMap, DDI, Shape.OptimizeFrame);
+    coro::salvageDebugInfo(ArgToAllocaMap, DDI, Shape.OptimizeFrame,
+                           true /*IsEntryPoint*/);
 
   return Shape;
 }

llvm/test/Transforms/Coroutines/swift-async-dbg.ll

@@ -19,9 +19,9 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineA(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      @llvm.dbg.declare(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
 ; CHECK:      @llvm.dbg.value(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                 DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_deref)
+; CHECK-SAME:                 DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      call {{.*}} @swift_task_switch
 
   %i7 = call ptr @llvm.coro.async.resume(), !dbg !54