[llvm] r348222 - [ARM64][Windows] Fix local stack size for funclets

[Sanjin Sijaric via llvm-commits]

Author: ssijaric
Date: Mon Dec  3 16:54:52 2018
New Revision: 348222

URL: http://llvm.org/viewvc/llvm-project?rev=348222&view=rev
Log:
[ARM64][Windows] Fix local stack size for funclets

The comment was misplaced, and the code didn't do what the comment indicated,
namely ignoring the varargs portion when computing the local stack size of a
funclet in emitEpilogue.  This results in incorrect offset computations within
funclets that are contained in vararg functions.

Differential Revision: https://reviews.llvm.org/D55096

Added:
    llvm/trunk/test/CodeGen/AArch64/funclet-local-stack-size.ll
Modified:
    llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp?rev=348222&r1=348221&r2=348222&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp Mon Dec  3 16:54:52 2018
@@ -1289,12 +1289,17 @@ void AArch64FrameLowering::emitEpilogue(
 
   bool IsWin64 =
       Subtarget.isCallingConvWin64(MF.getFunction().getCallingConv());
-  unsigned FixedObject = IsWin64 ? alignTo(AFI->getVarArgsGPRSize(), 16) : 0;
+  // Var args are accounted for in the containing function, so don't
+  // include them for funclets.
+  unsigned FixedObject =
+      (IsWin64 && !IsFunclet) ? alignTo(AFI->getVarArgsGPRSize(), 16) : 0;
 
   uint64_t AfterCSRPopSize = ArgumentPopSize;
   auto PrologueSaveSize = AFI->getCalleeSavedStackSize() + FixedObject;
-  // Var args are accounted for in the containting function, so don't
-  // include them for funclets.
+  // We cannot rely on the local stack size set in emitPrologue if the function
+  // has funclets, as funclets have different local stack size requirements, and
+  // the current value set in emitPrologue may be that of the containing
+  // function.
   if (MF.hasEHFunclets())
     AFI->setLocalStackSize(NumBytes - PrologueSaveSize);
   bool CombineSPBump = shouldCombineCSRLocalStackBump(MF, NumBytes);

Added: llvm/trunk/test/CodeGen/AArch64/funclet-local-stack-size.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/funclet-local-stack-size.ll?rev=348222&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/funclet-local-stack-size.ll (added)
+++ llvm/trunk/test/CodeGen/AArch64/funclet-local-stack-size.ll Mon Dec  3 16:54:52 2018
@@ -0,0 +1,53 @@
+; RUN: llc -o - %s -mtriple=aarch64-windows | FileCheck %s
+; Check that the local stack size is computed correctly for a funclet contained
+; within a varargs function.  The varargs component shouldn't be included in the
+; local stack size computation.
+target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-windows-msvc19.11.0"
+
+%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
+
+$"??_R0H at 8" = comdat any
+
+@"??_7type_info@@6B@" = external constant i8*
+@"??_R0H at 8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
+
+; CHECK-LABEL: ?catch$2@?0??func@@YAHHHZZ at 4HA
+; CHECK: stp x29, x30, [sp, #-16]!
+; CHECK: ldp x29, x30, [sp], #16
+; Function Attrs: uwtable
+define dso_local i32 @"?func@@YAHHHZZ"(i32 %a, i32, ...) local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %arr = alloca [10 x i32], align 4
+  %a2 = alloca i32, align 4
+  %1 = bitcast [10 x i32]* %arr to i8*
+  %arraydecay = getelementptr inbounds [10 x i32], [10 x i32]* %arr, i64 0, i64 0
+  %call = call i32 @"?init@@YAHPEAH at Z"(i32* nonnull %arraydecay)
+  %call1 = invoke i32 @"?func2@@YAHXZ"()
+          to label %cleanup unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %2 = catchswitch within none [label %catch] unwind to caller
+
+catch:                                            ; preds = %catch.dispatch
+  %3 = catchpad within %2 [%rtti.TypeDescriptor2* @"??_R0H at 8", i32 0, i32* %a2]
+  %4 = load i32, i32* %a2, align 4
+  %add = add nsw i32 %4, 1
+  catchret from %3 to label %cleanup
+
+cleanup:                                          ; preds = %entry, %catch
+  %retval.0 = phi i32 [ %add, %catch ], [ %call1, %entry ]
+  ret i32 %retval.0
+}
+
+declare dso_local i32 @"?init@@YAHPEAH at Z"(i32*)
+
+declare dso_local i32 @"?func2@@YAHXZ"()
+
+declare dso_local i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { uwtable }
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"wchar_size", i32 2}