[Coroutine] Update promise object's final layout index

promise is a header field but it is not guaranteed that it would be the third
field of the frame due to `performOptimizedStructLayout`.

Reviewed By: lxfind

Differential Revision: https://reviews.llvm.org/D94137

Author: Yuanfang Chen

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -758,6 +758,15 @@ static StructType *buildFrameType(Function &F, coro::Shape &Shape,
   // Because multiple allocas may own the same field slot,
   // we add allocas to field here.
   B.addFieldForAllocas(F, FrameData, Shape);
+  // Add PromiseAlloca to Allocas list so that
+  // 1. updateLayoutIndex could update its index after
+  // `performOptimizedStructLayout`
+  // 2. it is processed in insertSpills.
+  if (Shape.ABI == coro::ABI::Switch && PromiseAlloca)
+    // We assume that the promise alloca won't be modified before
+    // CoroBegin and no alias will be create before CoroBegin.
+    FrameData.Allocas.emplace_back(
+        PromiseAlloca, DenseMap<Instruction *, llvm::Optional<APInt>>{}, false);
   // Create an entry for every spilled value.
   for (auto &S : FrameData.Spills) {
     FieldIDType Id = B.addField(S.first->getType(), None);
@@ -2288,13 +2297,6 @@ void coro::buildCoroutineFrame(Function &F, Shape &Shape) {
       Shape.ABI == coro::ABI::Async)
     sinkSpillUsesAfterCoroBegin(F, FrameData, Shape.CoroBegin);
   Shape.FrameTy = buildFrameType(F, Shape, FrameData);
-  // Add PromiseAlloca to Allocas list so that it is processed in insertSpills.
-  if (Shape.ABI == coro::ABI::Switch && Shape.SwitchLowering.PromiseAlloca)
-    // We assume that the promise alloca won't be modified before
-    // CoroBegin and no alias will be create before CoroBegin.
-    FrameData.Allocas.emplace_back(
-        Shape.SwitchLowering.PromiseAlloca,
-        DenseMap<Instruction *, llvm::Optional<APInt>>{}, false);
   Shape.FramePtr = insertSpills(FrameData, Shape);
   lowerLocalAllocas(LocalAllocas, DeadInstructions);
 

llvm/test/Transforms/Coroutines/coro-spill-promise.ll

@@ -0,0 +1,57 @@
+; Check that promise object is reloaded from the correct index of the coro frame.
+; RUN: opt < %s -coro-split -S | FileCheck %s
+; RUN: opt < %s -passes=coro-split -S | FileCheck %s
+
+%"class.task::promise_type" = type { [64 x i8] }
+
+declare void @consume(i32*)
+declare void @consume2(%"class.task::promise_type"*)
+
+define i8* @f() "coroutine.presplit"="1" {
+entry:
+  %data = alloca i32, align 4
+  %__promise = alloca %"class.task::promise_type", align 64
+  %pv = bitcast %"class.task::promise_type"* %__promise to i8*
+  %id = call token @llvm.coro.id(i32 0, i8* %pv, i8* null, i8* null)
+  %size = call i32 @llvm.coro.size.i32()
+  %alloc = call i8* @malloc(i32 %size)
+  %hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc)
+  call void @consume(i32* %data)
+  %0 = call i8 @llvm.coro.suspend(token none, i1 false)
+  switch i8 %0, label %suspend [i8 0, label %resume
+                                i8 1, label %cleanup]
+resume:
+  call void @consume(i32* %data)
+  call void @consume2(%"class.task::promise_type"* %__promise)
+  br label %cleanup
+
+cleanup:
+  %mem = call i8* @llvm.coro.free(token %id, i8* %hdl)
+  call void @free(i8* %mem)
+  br label %suspend
+suspend:
+  call i1 @llvm.coro.end(i8* %hdl, i1 0)
+  ret i8* %hdl
+}
+
+; CHECK-LABEL: %f.Frame = type { void (%f.Frame*)*, void (%f.Frame*)*, i32, i1, [43 x i8], %"class.task::promise_type" }
+
+; CHECK-LABEL: @f.resume(
+; CHECK: %[[DATA:.+]] = getelementptr inbounds %f.Frame, %f.Frame* %FramePtr, i32 0, i32 5
+; CHECK: call void @consume2(%"class.task::promise_type"* %[[DATA]])
+; CHECK: ret void
+
+declare i8* @llvm.coro.free(token, i8*)
+declare i32 @llvm.coro.size.i32()
+declare i8  @llvm.coro.suspend(token, i1)
+declare void @llvm.coro.resume(i8*)
+declare void @llvm.coro.destroy(i8*)
+
+declare token @llvm.coro.id(i32, i8*, i8*, i8*)
+declare i1 @llvm.coro.alloc(token)
+declare i8* @llvm.coro.begin(token, i8*)
+declare i1 @llvm.coro.end(i8*, i1)
+
+declare noalias i8* @malloc(i32)
+declare double @print(double)
+declare void @free(i8*)