[WinEH] Correctly handle inlined __finally blocks with captures

We should also teach the inliner to collapse framerecover of
frameaddress of the current frame down to an alloca, but that can happen
later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235459 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/WinEHPrepare.cpp

@@ -175,7 +175,11 @@ public:
       : Materializer(HandlerFn, VarInfo),
         SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
         Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())),
-        LPadMap(LPadMap) {}
+        LPadMap(LPadMap) {
+    auto AI = HandlerFn->getArgumentList().begin();
+    ++AI;
+    EstablisherFrame = AI;
+  }
 
   CloningAction handleInstruction(ValueToValueMapTy &VMap,
                                   const Instruction *Inst,
@@ -210,6 +214,9 @@ protected:
   Type *SelectorIDType;
   Type *Int8PtrType;
   LandingPadMap &LPadMap;
+
+  /// The value representing the parent frame pointer.
+  Value *EstablisherFrame;
 };
 
 class WinEHCatchDirector : public WinEHCloningDirectorBase {
@@ -520,12 +527,24 @@ bool WinEHPrepare::prepareExceptionHandlers(
       Intrinsic::getDeclaration(M, Intrinsic::frameescape);
   Function *RecoverFrameFn =
       Intrinsic::getDeclaration(M, Intrinsic::framerecover);
+  SmallVector<Value *, 8> AllocasToEscape;
+
+  // Scan the entry block for an existing call to llvm.frameescape. We need to
+  // keep escaping those objects.
+  for (Instruction &I : F.front()) {
+    auto *II = dyn_cast<IntrinsicInst>(&I);
+    if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
+      auto Args = II->arg_operands();
+      AllocasToEscape.append(Args.begin(), Args.end());
+      II->eraseFromParent();
+      break;
+    }
+  }
 
   // Finally, replace all of the temporary allocas for frame variables used in
   // the outlined handlers with calls to llvm.framerecover.
   BasicBlock::iterator II = Entry->getFirstInsertionPt();
   Instruction *AllocaInsertPt = II;
-  SmallVector<Value *, 8> AllocasToEscape;
   for (auto &VarInfoEntry : FrameVarInfo) {
     Value *ParentVal = VarInfoEntry.first;
     TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
@@ -1051,6 +1070,11 @@ void LandingPadMap::remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
     VMap[Extract] = SelectorValue;
 }
 
+static bool isFrameAddressCall(const Value *V) {
+  return match(const_cast<Value *>(V),
+               m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
+}
+
 CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
     ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
   // If this is one of the boilerplate landing pad instructions, skip it.
@@ -1083,6 +1107,13 @@ CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
   if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
     return handleTypeIdFor(VMap, Inst, NewBB);
 
+  // When outlining llvm.frameaddress(i32 0), remap that to the second argument,
+  // which is the FP of the parent.
+  if (isFrameAddressCall(Inst)) {
+    VMap[Inst] = EstablisherFrame;
+    return CloningDirector::SkipInstruction;
+  }
+
   // Continue with the default cloning behavior.
   return CloningDirector::CloneInstruction;
 }
@@ -1584,10 +1615,6 @@ static void createCleanupHandler(LandingPadActions &Actions,
                << Action->getStartBlock()->getName() << "\n");
 }
 
-static bool isFrameAddressCall(Value *V) {
-  return match(V, m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
-}
-
 static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
                                          Instruction *MaybeCall) {
   // Look for finally blocks that Clang has already outlined for us.

test/CodeGen/WinEH/seh-inlined-finally.ll

@@ -6,9 +6,18 @@
 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
+%struct._RTL_CRITICAL_SECTION = type { %struct._RTL_CRITICAL_SECTION_DEBUG*, i32, i32, i8*, i8*, i64 }
+%struct._RTL_CRITICAL_SECTION_DEBUG = type { i16, i16, %struct._RTL_CRITICAL_SECTION*, %struct._LIST_ENTRY, i32, i32, i32, i16, i16 }
+%struct._LIST_ENTRY = type { %struct._LIST_ENTRY*, %struct._LIST_ENTRY* }
+
 declare i32 @puts(i8*)
 declare void @may_crash()
 declare i32 @__C_specific_handler(...)
+declare i8* @llvm.framerecover(i8*, i8*, i32) #1
+declare i8* @llvm.frameaddress(i32)
+declare void @llvm.frameescape(...)
+declare dllimport void @EnterCriticalSection(%struct._RTL_CRITICAL_SECTION*)
+declare dllimport void @LeaveCriticalSection(%struct._RTL_CRITICAL_SECTION*)
 
 define void @use_finally() {
 entry:
@@ -33,3 +42,42 @@ lpad:                                             ; preds = %entry
 ; CHECK-NEXT: cleanup
 ; CHECK-NEXT: call i8* (...) @llvm.eh.actions(i32 0, void (i8*, i8*)* @use_finally.cleanup)
 ; CHECK-NEXT: indirectbr i8* %recover, []
+
+; Function Attrs: nounwind uwtable
+define i32 @call_may_crash_locked() {
+entry:
+  %p = alloca %struct._RTL_CRITICAL_SECTION, align 8
+  call void (...) @llvm.frameescape(%struct._RTL_CRITICAL_SECTION* %p)
+  call void @EnterCriticalSection(%struct._RTL_CRITICAL_SECTION* %p)
+  invoke void @may_crash()
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:                                      ; preds = %entry
+  %tmp2 = call i8* @llvm.frameaddress(i32 0)
+  %tmp3 = call i8* @llvm.framerecover(i8* bitcast (i32 ()* @call_may_crash_locked to i8*), i8* %tmp2, i32 0) #2
+  %tmp6 = bitcast i8* %tmp3 to %struct._RTL_CRITICAL_SECTION*
+  call void @LeaveCriticalSection(%struct._RTL_CRITICAL_SECTION* %tmp6)
+  ret i32 42
+
+lpad:                                             ; preds = %entry
+  %tmp7 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__C_specific_handler to i8*)
+            cleanup
+  %tmp8 = call i8* @llvm.frameaddress(i32 0)
+  %tmp9 = call i8* @llvm.framerecover(i8* bitcast (i32 ()* @call_may_crash_locked to i8*), i8* %tmp8, i32 0)
+  %tmp12 = bitcast i8* %tmp9 to %struct._RTL_CRITICAL_SECTION*
+  call void @LeaveCriticalSection(%struct._RTL_CRITICAL_SECTION* %tmp12)
+  resume { i8*, i32 } %tmp7
+}
+
+; CHECK-LABEL: define i32 @call_may_crash_locked()
+; CHECK: invoke void @may_crash()
+;
+; CHECK: landingpad
+; CHECK-NEXT: cleanup
+; CHECK-NEXT: call i8* (...) @llvm.eh.actions(i32 0, void (i8*, i8*)* @call_may_crash_locked.cleanup)
+; CHECK-NEXT: indirectbr i8* %recover, []
+
+; CHECK-LABEL: define internal void @call_may_crash_locked.cleanup(i8*, i8*)
+; CHECK: %tmp9 = call i8* @llvm.framerecover(i8* bitcast (i32 ()* @call_may_crash_locked to i8*), i8* %1, i32 0)
+; CHECK: %tmp12 = bitcast i8* %tmp9 to %struct._RTL_CRITICAL_SECTION*
+; CHECK: call void @LeaveCriticalSection(%struct._RTL_CRITICAL_SECTION* %tmp12)