[llvm] [Coroutines] Split buildCoroutineFrame into normalization and frame building (PR #108076)

[Tyler Nowicki via llvm-commits]

https://github.com/TylerNowicki created https://github.com/llvm/llvm-project/pull/108076

* Split buildCoroutineFrame into code related to normalization and code related to actually building the coroutine frame.
* This will enable future specialization of buildCoroutineFrame for different ABIs while the normalization can be done by splitCoroutine prior to calling buildCoroutineFrame.

See RFC for more info: https://discourse.llvm.org/t/rfc-abi-objects-for-coroutines/81057

>From 34559ad06f82f7d1b48f7982e7a64944d72204b4 Mon Sep 17 00:00:00 2001
From: tnowicki <tnowicki.nowicki at amd.com>
Date: Fri, 23 Aug 2024 13:13:20 -0400
Subject: [PATCH] [Coroutines] Split buildCoroutineFrame

* Split buildCoroutineFrame into code related to normalization and code
  related to actually building the coroutine frame.
* This will enable future specialization of buildCoroutineFrame for
  different ABIs.
---
 llvm/lib/Transforms/Coroutines/CoroFrame.cpp  | 14 ++++++++------
 llvm/lib/Transforms/Coroutines/CoroInternal.h |  4 +++-
 llvm/lib/Transforms/Coroutines/CoroSplit.cpp  |  3 ++-
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index 4b76fc79361008..8ee4bfa3b888df 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1754,7 +1754,8 @@ static bool willLeaveFunctionImmediatelyAfter(BasicBlock *BB,
   if (depth == 0) return false;
 
   // If this is a suspend block, we're about to exit the resumption function.
-  if (isSuspendBlock(BB)) return true;
+  if (isSuspendBlock(BB))
+    return true;
 
   // Recurse into the successors.
   for (auto *Succ : successors(BB)) {
@@ -2288,9 +2289,8 @@ static void doRematerializations(
   rewriteMaterializableInstructions(AllRemats);
 }
 
-void coro::buildCoroutineFrame(
-    Function &F, Shape &Shape, TargetTransformInfo &TTI,
-    const std::function<bool(Instruction &)> &MaterializableCallback) {
+void coro::normalizeCoroutine(Function &F, coro::Shape &Shape,
+                              TargetTransformInfo &TTI) {
   // Don't eliminate swifterror in async functions that won't be split.
   if (Shape.ABI != coro::ABI::Async || !Shape.CoroSuspends.empty())
     eliminateSwiftError(F, Shape);
@@ -2337,10 +2337,12 @@ void coro::buildCoroutineFrame(
   // Transforms multi-edge PHI Nodes, so that any value feeding into a PHI will
   // never have its definition separated from the PHI by the suspend point.
   rewritePHIs(F);
+}
 
-  // Build suspend crossing info.
+void coro::buildCoroutineFrame(
+    Function &F, Shape &Shape,
+    const std::function<bool(Instruction &)> &MaterializableCallback) {
   SuspendCrossingInfo Checker(F, Shape.CoroSuspends, Shape.CoroEnds);
-
   doRematerializations(F, Checker, MaterializableCallback);
 
   const DominatorTree DT(F);
diff --git a/llvm/lib/Transforms/Coroutines/CoroInternal.h b/llvm/lib/Transforms/Coroutines/CoroInternal.h
index be86f96525b677..698c21a797420a 100644
--- a/llvm/lib/Transforms/Coroutines/CoroInternal.h
+++ b/llvm/lib/Transforms/Coroutines/CoroInternal.h
@@ -281,8 +281,10 @@ struct LLVM_LIBRARY_VISIBILITY Shape {
 };
 
 bool defaultMaterializable(Instruction &V);
+void normalizeCoroutine(Function &F, coro::Shape &Shape,
+                        TargetTransformInfo &TTI);
 void buildCoroutineFrame(
-    Function &F, Shape &Shape, TargetTransformInfo &TTI,
+    Function &F, Shape &Shape,
     const std::function<bool(Instruction &)> &MaterializableCallback);
 CallInst *createMustTailCall(DebugLoc Loc, Function *MustTailCallFn,
                              TargetTransformInfo &TTI,
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index 494c4d632de95f..dc3829d7f28eb1 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -2030,7 +2030,8 @@ splitCoroutine(Function &F, SmallVectorImpl<Function *> &Clones,
   lowerAwaitSuspends(F, Shape);
 
   simplifySuspendPoints(Shape);
-  buildCoroutineFrame(F, Shape, TTI, MaterializableCallback);
+  normalizeCoroutine(F, Shape, TTI);
+  buildCoroutineFrame(F, Shape, MaterializableCallback);
   replaceFrameSizeAndAlignment(Shape);
   bool isNoSuspendCoroutine = Shape.CoroSuspends.empty();