Backport fixes for aarch64-pc-windows-msvc (#45)

* [CodeView] Add pragma push/pop_macro for ARM64_FPSR to enum header

This fixes (one aspect of) compilation of LLDB with MSVC for ARM64.

LLDB source files include intrin.h, and the MSVC intrin.h transitively
includes arm64intr.h, which has an ARM64_FPSR define, which clashes
with the enum declaration.

Differential Revision: https://reviews.llvm.org/D67864

llvm-svn: 372481

* [AArch64] Fix mismatch in prologue and epilogue for funclets on Windows

The generated code for a funclet can have an add to sp in the epilogue
for which there is no corresponding sub in the prologue.

This patch removes the early return from emitPrologue that was
preventing the sub to sp, and instead conditionalizes the appropriate
parts of the rest of the function.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45345

Differential Revision: https://reviews.llvm.org/D77015

* [AArch64] Change AArch64 Windows EH UnwindHelp object to be a fixed object

The UnwindHelp object is used during exception handling by runtime
code. It must be findable from a fixed offset from FP.

This change allocates the UnwindHelp object as a fixed object (as is
done for x86_64) to ensure that both the generated code and runtime
agree on the location of the object.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45346

Differential Revision: https://reviews.llvm.org/D77016

Co-authored-by: Martin Storsjo <[email protected]>

Author: danielframpton

llvm/include/llvm/DebugInfo/CodeView/CodeViewRegisters.def

@@ -368,6 +368,11 @@ CV_REGISTER(AMD64_K7, 765)
 
 #if defined(CV_REGISTERS_ALL) || defined(CV_REGISTERS_ARM64)
 
+// arm64intr.h from MSVC defines ARM64_FPSR, which conflicts with
+// these declarations.
+#pragma push_macro("ARM64_FPSR")
+#undef ARM64_FPSR
+
 // ARM64 registers
 
 CV_REGISTER(ARM64_NOREG, 0)
@@ -556,4 +561,6 @@ CV_REGISTER(ARM64_Q31, 211)
 
 CV_REGISTER(ARM64_FPSR, 220)
 
+#pragma pop_macro("ARM64_FPSR")
+
 #endif // defined(CV_REGISTERS_ALL) || defined(CV_REGISTERS_ARM64)

llvm/lib/Target/AArch64/AArch64FrameLowering.cpp

@@ -183,6 +183,24 @@ static unsigned estimateRSStackSizeLimit(MachineFunction &MF) {
   return DefaultSafeSPDisplacement;
 }
 
+/// Returns the size of the fixed object area (allocated next to sp on entry)
+/// On Win64 this may include a var args area and an UnwindHelp object for EH.
+static unsigned getFixedObjectSize(const MachineFunction &MF,
+                                   const AArch64FunctionInfo *AFI, bool IsWin64,
+                                   bool IsFunclet) {
+  if (!IsWin64 || IsFunclet) {
+    // Only Win64 uses fixed objects, and then only for the function (not
+    // funclets)
+    return 0;
+  } else {
+    // Var args are stored here in the primary function.
+    const unsigned VarArgsArea = AFI->getVarArgsGPRSize();
+    // To support EH funclets we allocate an UnwindHelp object
+    const unsigned UnwindHelpObject = (MF.hasEHFunclets() ? 8 : 0);
+    return alignTo(VarArgsArea + UnwindHelpObject, 16);
+  }
+}
+
 bool AArch64FrameLowering::canUseRedZone(const MachineFunction &MF) const {
   if (!EnableRedZone)
     return false;
@@ -891,10 +909,7 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
 
   bool IsWin64 =
       Subtarget.isCallingConvWin64(MF.getFunction().getCallingConv());
-  // 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;
+  unsigned FixedObject = getFixedObjectSize(MF, AFI, IsWin64, IsFunclet);
 
   auto PrologueSaveSize = AFI->getCalleeSavedStackSize() + FixedObject;
   // All of the remaining stack allocations are for locals.
@@ -922,32 +937,8 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
     ++MBBI;
   }
 
-  // The code below is not applicable to funclets. We have emitted all the SEH
-  // opcodes that we needed to emit.  The FP and BP belong to the containing
-  // function.
-  if (IsFunclet) {
-    if (NeedsWinCFI) {
-      HasWinCFI = true;
-      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
-          .setMIFlag(MachineInstr::FrameSetup);
-    }
-
-    // SEH funclets are passed the frame pointer in X1.  If the parent
-    // function uses the base register, then the base register is used
-    // directly, and is not retrieved from X1.
-    if (F.hasPersonalityFn()) {
-      EHPersonality Per = classifyEHPersonality(F.getPersonalityFn());
-      if (isAsynchronousEHPersonality(Per)) {
-        BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::COPY), AArch64::FP)
-            .addReg(AArch64::X1).setMIFlag(MachineInstr::FrameSetup);
-        MBB.addLiveIn(AArch64::X1);
-      }
-    }
-
-    return;
-  }
-
-  if (HasFP) {
+  // For funclets the FP belongs to the containing function.
+  if (!IsFunclet && HasFP) {
     // Only set up FP if we actually need to. Frame pointer is fp =
     // sp - fixedobject - 16.
     int FPOffset = AFI->getCalleeSavedStackSize() - 16;
@@ -1058,7 +1049,9 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
 
   // Allocate space for the rest of the frame.
   if (NumBytes) {
-    const bool NeedsRealignment = RegInfo->needsStackRealignment(MF);
+    // Alignment is required for the parent frame, not the funclet
+    const bool NeedsRealignment =
+        !IsFunclet && RegInfo->needsStackRealignment(MF);
     unsigned scratchSPReg = AArch64::SP;
 
     if (NeedsRealignment) {
@@ -1111,7 +1104,8 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
   // FIXME: Clarify FrameSetup flags here.
   // Note: Use emitFrameOffset() like above for FP if the FrameSetup flag is
   // needed.
-  if (RegInfo->hasBasePointer(MF)) {
+  // For funclets the BP belongs to the containing function.
+  if (!IsFunclet && RegInfo->hasBasePointer(MF)) {
     TII->copyPhysReg(MBB, MBBI, DL, RegInfo->getBaseRegister(), AArch64::SP,
                      false);
     if (NeedsWinCFI) {
@@ -1128,6 +1122,18 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
         .setMIFlag(MachineInstr::FrameSetup);
   }
 
+  // SEH funclets are passed the frame pointer in X1.  If the parent
+  // function uses the base register, then the base register is used
+  // directly, and is not retrieved from X1.
+  if (IsFunclet && F.hasPersonalityFn()) {
+    EHPersonality Per = classifyEHPersonality(F.getPersonalityFn());
+    if (isAsynchronousEHPersonality(Per)) {
+      BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::COPY), AArch64::FP)
+          .addReg(AArch64::X1).setMIFlag(MachineInstr::FrameSetup);
+      MBB.addLiveIn(AArch64::X1);
+    }
+  }
+
   if (needsFrameMoves) {
     const DataLayout &TD = MF.getDataLayout();
     const int StackGrowth = -TD.getPointerSize(0);
@@ -1344,10 +1350,7 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
 
   bool IsWin64 =
       Subtarget.isCallingConvWin64(MF.getFunction().getCallingConv());
-  // 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;
+  unsigned FixedObject = getFixedObjectSize(MF, AFI, IsWin64, IsFunclet);
 
   uint64_t AfterCSRPopSize = ArgumentPopSize;
   auto PrologueSaveSize = AFI->getCalleeSavedStackSize() + FixedObject;
@@ -1517,7 +1520,8 @@ static int getFPOffset(const MachineFunction &MF, int ObjectOffset) {
   const auto &Subtarget = MF.getSubtarget<AArch64Subtarget>();
   bool IsWin64 =
       Subtarget.isCallingConvWin64(MF.getFunction().getCallingConv());
-  unsigned FixedObject = IsWin64 ? alignTo(AFI->getVarArgsGPRSize(), 16) : 0;
+  unsigned FixedObject =
+      getFixedObjectSize(MF, AFI, IsWin64, /*IsFunclet=*/false);
   return ObjectOffset + FixedObject + 16;
 }
 
@@ -2197,9 +2201,15 @@ void AArch64FrameLowering::processFunctionBeforeFrameFinalized(
     ++MBBI;
 
   // Create an UnwindHelp object.
-  int UnwindHelpFI =
-      MFI.CreateStackObject(/*size*/8, /*alignment*/16, false);
+  // The UnwindHelp object is allocated at the start of the fixed object area
+  const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
+  int64_t FixedObject =
+      getFixedObjectSize(MF, AFI, /*IsWin64*/ true, /*IsFunclet*/ false);
+  int UnwindHelpFI = MFI.CreateFixedObject(/*Size*/ 8,
+                                           /*SPOffset*/ -FixedObject,
+                                           /*IsImmutable=*/false);
   EHInfo.UnwindHelpFrameIdx = UnwindHelpFI;
+
   // We need to store -2 into the UnwindHelp object at the start of the
   // function.
   DebugLoc DL;
@@ -2221,10 +2231,14 @@ int AArch64FrameLowering::getFrameIndexReferencePreferSP(
     const MachineFunction &MF, int FI, unsigned &FrameReg,
     bool IgnoreSPUpdates) const {
   const MachineFrameInfo &MFI = MF.getFrameInfo();
-  LLVM_DEBUG(dbgs() << "Offset from the SP for " << FI << " is "
-                    << MFI.getObjectOffset(FI) << "\n");
-  FrameReg = AArch64::SP;
-  return MFI.getObjectOffset(FI);
+  if (IgnoreSPUpdates) {
+    LLVM_DEBUG(dbgs() << "Offset from the SP for " << FI << " is "
+                      << MFI.getObjectOffset(FI) << "\n");
+    FrameReg = AArch64::SP;
+    return MFI.getObjectOffset(FI);
+  }
+
+  return getFrameIndexReference(MF, FI, FrameReg);
 }
 
 /// The parent frame offset (aka dispFrame) is only used on X86_64 to retrieve

llvm/test/CodeGen/AArch64/funclet-match-add-sub-stack.ll

@@ -0,0 +1,62 @@
+; RUN: llc -o - %s -mtriple=aarch64-windows | FileCheck %s
+; Check that the stack bump around a funclet is computed correctly in both the
+; prologue and epilogue in the case we have a MaxCallFrameSize > 0 and are doing alloca
+target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-pc-windows-msvc19.25.28611"
+
+; // requires passing arguments on the stack
+; void test2(void*, int, int, int, int, int, int, int, int);
+;
+; // function with the funclet being checked
+; void test1(size_t bytes)
+; {
+;   // alloca forces a separate callee save bump and stack bump
+;   void *data = _alloca(bytes);
+;   try {
+;     test2(data, 0, 1, 2, 3, 4, 5, 6, 7);
+;   } catch (...) {
+;     // the funclet being checked
+;   }
+; }
+
+; CHECK-LABEL: ?catch$2@?0??test1@@YAX_K@Z@4HA
+; CHECK: sub sp, sp, #16
+; CHECK: add sp, sp, #16
+; Function Attrs: uwtable
+define dso_local void @"?test1@@YAX_K@Z"(i64) #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+  %2 = alloca i64, align 8
+  %3 = alloca i8*, align 8
+  store i64 %0, i64* %2, align 8
+  %4 = load i64, i64* %2, align 8
+  %5 = alloca i8, i64 %4, align 16
+  store i8* %5, i8** %3, align 8
+  %6 = load i8*, i8** %3, align 8
+  invoke void @"?test2@@YAXPEAXHHHHHHHH@Z"(i8* %6, i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7)
+          to label %13 unwind label %7
+
+7:                                                ; preds = %1
+  %8 = catchswitch within none [label %9] unwind to caller
+
+9:                                                ; preds = %7
+  %10 = catchpad within %8 [i8* null, i32 64, i8* null]
+  catchret from %10 to label %11
+
+11:                                               ; preds = %9
+  br label %12
+
+12:                                               ; preds = %11, %13
+  ret void
+
+13:                                               ; preds = %1
+  br label %12
+}
+
+declare dso_local void @"?test2@@YAXPEAXHHHHHHHH@Z"(i8*, i32, i32, i32, i32, i32, i32, i32, i32) #1
+
+declare dso_local i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { uwtable }
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"wchar_size", i32 2}

llvm/test/CodeGen/AArch64/seh-finally.ll

@@ -37,7 +37,7 @@ entry:
 ; CHECK-LABEL: simple_seh
 ; CHECK: add     x29, sp, #16
 ; CHECK: mov     x0, #-2
-; CHECK: stur    x0, [x29, #-16]
+; CHECK: stur    x0, [x29, #16]
 ; CHECK: .set .Lsimple_seh$frame_escape_0, -8
 ; CHECK: ldur    w0, [x29, #-8]
 ; CHECK: bl      foo
@@ -87,13 +87,13 @@ define void @stack_realign() #0 personality i8* bitcast (i32 (...)* @__C_specifi
 entry:
 ; CHECK-LABEL: stack_realign
 ; CHECK: add     x29, sp, #16
-; CHECK: sub     x9, sp, #64
+; CHECK: sub     x9, sp, #16
 ; CHECK: and     sp, x9, #0xffffffffffffffe0
 ; CHECK: mov     x19, sp
 ; CHECK: mov     x0, #-2
-; CHECK: stur    x0, [x19, #16]
-; CHECK: .set .Lstack_realign$frame_escape_0, 32
-; CHECK: ldr     w0, [x19, #32]
+; CHECK: stur    x0, [x29, #16]
+; CHECK: .set .Lstack_realign$frame_escape_0, 0
+; CHECK: ldr     w0, [x19]
 ; CHECK: bl      foo
 
   %o = alloca %struct.S, align 32
@@ -142,7 +142,7 @@ entry:
 ; CHECK-LABEL: vla_present
 ; CHECK: add     x29, sp, #32
 ; CHECK: mov     x1, #-2
-; CHECK: stur    x1, [x29, #-32]
+; CHECK: stur    x1, [x29, #16]
 ; CHECK: .set .Lvla_present$frame_escape_0, -4
 ; CHECK: stur    w0, [x29, #-4]
 ; CHECK: ldur    w8, [x29, #-4]
@@ -206,17 +206,17 @@ define void @vla_and_realign(i32 %n) #0 personality i8* bitcast (i32 (...)* @__C
 entry:
 ; CHECK-LABEL: vla_and_realign
 ; CHECK: add     x29, sp, #16
-; CHECK: sub     x9, sp, #64
+; CHECK: sub     x9, sp, #48
 ; CHECK: and     sp, x9, #0xffffffffffffffe0
 ; CHECK: mov     x19, sp
 ; CHECK: mov     x1, #-2
-; CHECK: stur    x1, [x19]
+; CHECK: stur    x1, [x29, #16]
 ; CHECK: .set .Lvla_and_realign$frame_escape_0, 32
-; CHECK: stur    w0, [x29, #-4]
-; CHECK: ldur    w8, [x29, #-4]
+; CHECK: str     w0, [x29, #28]
+; CHECK: ldr     w8, [x29, #28]
 ; CHECK: mov     x9, sp
-; CHECK: str     x9, [x19, #24]
-; CHECK: str     x8, [x19, #16]
+; CHECK: str     x9, [x19, #56]
+; CHECK: str     x8, [x19, #24]
 ; CHECK: ldr     w0, [x19, #32]
 ; CHECK: bl      foo
 

llvm/test/CodeGen/AArch64/wineh-try-catch-cbz.ll

@@ -4,11 +4,10 @@
 ; but the original issue only reproduced if the cbz was immediately
 ; after the frame setup.)
 
-; CHECK:      sub     sp, sp, #32
-; CHECK-NEXT: stp     x29, x30, [sp, #16]
-; CHECK-NEXT: add     x29, sp, #16
+; CHECK: stp     x29, x30, [sp, #-32]!
+; CHECK-NEXT: mov     x29, sp
 ; CHECK-NEXT: mov     x1, #-2
-; CHECK-NEXT: stur    x1, [x29, #-16]
+; CHECK-NEXT: stur    x1, [x29, #16]
 ; CHECK-NEXT: cbz     w0, .LBB0_2
 
 target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"

llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll

@@ -12,7 +12,7 @@
 ; CHECK:      str     x28, [sp, #-32]!
 ; CHECK-NEXT: str     x19, [sp, #8]
 ; CHECK-NEXT: stp     x29, x30, [sp, #16]
-; CHECK-NEXT: add     x0, x19, #64
+; CHECK-NEXT: add     x0, x19, #0
 ; CHECK-NEXT: mov     w1, wzr
 ; CHECK-NEXT: bl      "?bb@@YAXPEAHH@Z"
 ; CHECK-NEXT: adrp    x0, .LBB0_1

llvm/test/CodeGen/AArch64/wineh-try-catch.ll

@@ -11,19 +11,19 @@
 ;    and the parent function.
 
 ; The following checks that the unwind help object has -2 stored into it at
-; fp - 400 - 256 = fp - 656, which is on-entry sp - 48 + 32 - 656 =
-; on-entry sp - 672.  We check this offset in the table later on.
+; fp + 16, which is on-entry sp - 16.
+; We check this offset in the table later on.
 
 ; CHECK-LABEL: "?func@@YAHXZ":
-; CHECK:       str     x28, [sp, #-48]!
+; CHECK        str     x28, [sp, #-64]!
 ; CHECK:       str     x21, [sp, #8]
 ; CHECK:       stp     x19, x20, [sp, #16]
 ; CHECK:       stp     x29, x30, [sp, #32]
 ; CHECK:       add     x29, sp, #32
 ; CHECK:       sub     sp, sp, #624
 ; CHECK:       mov     x19, sp
 ; CHECK:       mov     x0, #-2
-; CHECK:       stur    x0, [x19]
+; CHECK:       stur    x0, [x29, #16]
 
 ; Now check that x is stored at fp - 20.  We check that this is the same
 ; location accessed from the funclet to retrieve x.
@@ -72,7 +72,7 @@
 
 ; Now check that the offset of the unwind help object from the stack pointer on
 ; entry to func is encoded in cppxdata that is passed to __CxxFrameHandler3.  As
-; computed above, this comes to -672.
+; computed above, this comes to -16.
 ; CHECK-LABEL:        "$cppxdata$?func@@YAHXZ":
 ; CHECK-NEXT:         .word   429065506               ; MagicNumber
 ; CHECK-NEXT:         .word   2                       ; MaxState
@@ -81,17 +81,17 @@
 ; CHECK-NEXT:         .word   ("$tryMap$?func@@YAHXZ")@IMGREL ; TryBlockMap
 ; CHECK-NEXT:         .word   4                       ; IPMapEntries
 ; CHECK-NEXT:         .word   ("$ip2state$?func@@YAHXZ")@IMGREL ; IPToStateXData
-; CHECK-NEXT:         .word   -672                    ; UnwindHelp
+; CHECK-NEXT:         .word   -16                     ; UnwindHelp
 
 ; UNWIND: Function: ?func@@YAHXZ (0x0)
 ; UNWIND: Prologue [
 ; UNWIND-NEXT: ; nop
 ; UNWIND-NEXT: ; sub sp, #624
-; UNWIND-NEXT: ; add fp, sp, #32
-; UNWIND-NEXT: ; stp x29, x30, [sp, #32]
-; UNWIND-NEXT: ; stp x19, x20, [sp, #16]
-; UNWIND-NEXT: ; str x21, [sp, #8]
-; UNWIND-NEXT: ; str x28, [sp, #48]!
+; UNWIND-NEXT: ; mov fp, sp
+; UNWIND-NEXT: ; stp x19, x20, [sp, #32]
+; UNWIND-NEXT: ; str x21, [sp, #24]
+; UNWIND-NEXT: ; str x28, [sp, #16]
+; UNWIND-NEXT: ; stp x29, x30, [sp, #-64]!
 ; UNWIND-NEXT: ; end
 ; UNWIND: Function: ?catch$2@?0??func@@YAHXZ@4HA
 ; UNWIND: Prologue [