[WinEH] Sink UnwindHelp completely out of IR

We don't need to represent UnwindHelp in IR.  Instead, we can use the
knowledge that we are emitting the parent function to decide if we
should create the UnwindHelp stack object.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234061 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/ExceptionHandling.rst b/docs/ExceptionHandling.rst
index 6c33e0b363c52e65f77569a8d15db4ec049ca834..72ed78a3c99a7398f55fd941e5a492f280b816e5 100644 (file)
--- a/docs/ExceptionHandling.rst
+++ b/docs/ExceptionHandling.rst
@@ -543,18 +543,6 @@ In order to preserve the structure of the CFG, a call to '``llvm.eh.actions``'
 must be followed by an ':ref:`indirectbr <i_indirectbr>`' instruction that
 jumps to the result of the intrinsic call.
 
-``llvm.eh.unwindhelp``
-----------------------
-
-.. code-block:: llvm
-
-  void @llvm.eh.unwindhelp(i8*)
-
-This intrinsic designates the provided static alloca as the unwind help object.
-This object is used by Windows native exception handling on non-x86 platforms
-where xdata unwind information is used. It is typically an 8 byte chunk of
-memory treated as two 32-bit integers.
-
 
 SJLJ Intrinsics
 ---------------

diff --git a/include/llvm/CodeGen/MachineFrameInfo.h b/include/llvm/CodeGen/MachineFrameInfo.h
index 667736021f9271719270f8f20bcc93dc4f6de039..1e7fee666fc9eaa65cf5980db8175fdadf1de748 100644 (file)
--- a/include/llvm/CodeGen/MachineFrameInfo.h
+++ b/include/llvm/CodeGen/MachineFrameInfo.h
@@ -516,10 +516,6 @@ public:
   /// on the stack.  Returns an index with a negative value.
   int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset);
 
-  /// Allocates memory at a fixed, target-specific offset from the frame
-  /// pointer. Marks the function as having its frame address taken.
-  int CreateFrameAllocation(uint64_t Size);
-
   /// isFixedObjectIndex - Returns true if the specified index corresponds to a
   /// fixed stack object.
   bool isFixedObjectIndex(int ObjectIdx) const {

diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td
index e0e8d674e1631edb1ec5687fcfc6911c4dd4f7c2..4052a312fd0bad670aa1a26f245f76b8dc974779 100644 (file)
--- a/include/llvm/IR/Intrinsics.td
+++ b/include/llvm/IR/Intrinsics.td
@@ -421,10 +421,6 @@ def int_eh_endcatch : Intrinsic<[], []>;
 // Represents the list of actions to take when an exception is thrown.
 def int_eh_actions : Intrinsic<[llvm_ptr_ty], [llvm_vararg_ty], []>;
 
-// Designates the provided static alloca as the unwind help object. Required
-// for WinEH.
-def int_eh_unwindhelp : Intrinsic<[], [llvm_ptr_ty], []>;
-
 // __builtin_unwind_init is an undocumented GCC intrinsic that causes all
 // callee-saved registers to be saved and restored (regardless of whether they
 // are used) in the calling function. It is used by libgcc_eh.

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index dde8434e0b9ea0c514518b0eab9af7036d0fec99..008d7dc2b2563d4f98ae61722f1a0c0878f58a00 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5453,17 +5453,6 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   case Intrinsic::eh_begincatch:
   case Intrinsic::eh_endcatch:
     llvm_unreachable("begin/end catch intrinsics not lowered in codegen");
-  case Intrinsic::eh_unwindhelp: {
-    AllocaInst *Slot =
-        cast<AllocaInst>(I.getArgOperand(0)->stripPointerCasts());
-    assert(FuncInfo.StaticAllocaMap.count(Slot) &&
-           "can only use static allocas with llvm.eh.unwindhelp");
-    int FI = FuncInfo.StaticAllocaMap[Slot];
-    MachineFunction &MF = DAG.getMachineFunction();
-    MachineModuleInfo &MMI = MF.getMMI();
-    MMI.getWinEHFuncInfo(MF.getFunction()).UnwindHelpFrameIdx = FI;
-    return nullptr;
-  }
   }
 }
 

diff --git a/lib/CodeGen/WinEHPrepare.cpp b/lib/CodeGen/WinEHPrepare.cpp
index d030a7d44cd5f3864777ebd39c3b1de8181b899d..d12a8ed472bce1f96e3fdc11af44eeae2f63aabf 100644 (file)
--- a/lib/CodeGen/WinEHPrepare.cpp
+++ b/lib/CodeGen/WinEHPrepare.cpp
@@ -607,20 +607,6 @@ bool WinEHPrepare::prepareExceptionHandlers(
   Builder.SetInsertPoint(&F.getEntryBlock().back());
   Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
 
-  // Insert an alloca for the EH state in the entry block. On x86, we will also
-  // insert stores to update the EH state, but on other ISAs, the runtime does
-  // it for us.
-  // FIXME: This record is different on x86.
-  Type *UnwindHelpTy = Type::getInt64Ty(Context);
-  AllocaInst *UnwindHelp =
-      new AllocaInst(UnwindHelpTy, "unwindhelp", &F.getEntryBlock().front());
-  Builder.CreateStore(llvm::ConstantInt::get(UnwindHelpTy, -2), UnwindHelp,
-                      /*isVolatile=*/true);
-  Function *UnwindHelpFn =
-      Intrinsic::getDeclaration(M, Intrinsic::eh_unwindhelp);
-  Builder.CreateCall(UnwindHelpFn,
-                     Builder.CreateBitCast(UnwindHelp, Int8PtrType));
-
   // Clean up the handler action maps we created for this function
   DeleteContainerSeconds(CatchHandlerMap);
   CatchHandlerMap.clear();

diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 15e354b8dfc522f8d68897974cd76968db72591d..accd5cd8940dbd4347dbe81eca37bdd37d691e0e 100644 (file)
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -3230,13 +3230,6 @@ void Verifier::visitIntrinsicFunctionCall(Intrinsic::ID ID, CallInst &CI) {
     break;
   }
 
-  case Intrinsic::eh_unwindhelp: {
-    auto *AI = dyn_cast<AllocaInst>(CI.getArgOperand(0)->stripPointerCasts());
-    Assert(AI && AI->isStaticAlloca(),
-           "llvm.eh.unwindhelp requires a static alloca", &CI);
-    break;
-  }
-
   case Intrinsic::experimental_gc_statepoint:
     Assert(!CI.isInlineAsm(),
            "gc.statepoint support for inline assembly unimplemented", &CI);

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index de81949e0cc4accee4932f01ba9ab28a37ed5d9d..3055256605a1831c778935422f8e6020fb62e30a 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2267,12 +2267,6 @@ static ArrayRef<MCPhysReg> get64BitArgumentXMMs(MachineFunction &MF,
   return makeArrayRef(std::begin(XMMArgRegs64Bit), std::end(XMMArgRegs64Bit));
 }
 
-static bool isOutlinedHandler(const MachineFunction &MF) {
-  const MachineModuleInfo &MMI = MF.getMMI();
-  const Function *F = MF.getFunction();
-  return MMI.getWinEHParent(F) != F;
-}
-
 SDValue
 X86TargetLowering::LowerFormalArguments(SDValue Chain,
                                         CallingConv::ID CallConv,
@@ -2424,6 +2418,13 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
         MFI->CreateFixedObject(1, StackSize, true));
   }
 
+  MachineModuleInfo &MMI = MF.getMMI();
+  const Function *WinEHParent = nullptr;
+  if (IsWin64 && MMI.hasWinEHFuncInfo(Fn))
+    WinEHParent = MMI.getWinEHParent(Fn);
+  bool IsWinEHOutlined = WinEHParent && WinEHParent != Fn;
+  bool IsWinEHParent = WinEHParent && WinEHParent == Fn;
+
   // Figure out if XMM registers are in use.
   assert(!(MF.getTarget().Options.UseSoftFloat &&
            Fn->hasFnAttribute(Attribute::NoImplicitFloat)) &&
@@ -2512,14 +2513,13 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
 
     if (!MemOps.empty())
       Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOps);
-  } else if (IsWin64 && isOutlinedHandler(MF)) {
+  } else if (IsWinEHOutlined) {
     // Get to the caller-allocated home save location.  Add 8 to account
     // for the return address.
     int HomeOffset = TFI.getOffsetOfLocalArea() + 8;
     FuncInfo->setRegSaveFrameIndex(MFI->CreateFixedObject(
         /*Size=*/1, /*SPOffset=*/HomeOffset + 8, /*Immutable=*/false));
 
-    MachineModuleInfo &MMI = MF.getMMI();
     MMI.getWinEHFuncInfo(Fn)
         .CatchHandlerParentFrameObjIdx[const_cast<Function *>(Fn)] =
         FuncInfo->getRegSaveFrameIndex();
@@ -2600,6 +2600,17 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
 
   FuncInfo->setArgumentStackSize(StackSize);
 
+  if (IsWinEHParent) {
+    int UnwindHelpFI = MFI->CreateStackObject(8, 8, /*isSS=*/false);
+    SDValue StackSlot = DAG.getFrameIndex(UnwindHelpFI, MVT::i64);
+    MMI.getWinEHFuncInfo(MF.getFunction()).UnwindHelpFrameIdx = UnwindHelpFI;
+    SDValue Neg2 = DAG.getConstant(-2, MVT::i64);
+    Chain = DAG.getStore(Chain, dl, Neg2, StackSlot,
+                         MachinePointerInfo::getFixedStack(UnwindHelpFI),
+                         /*isVolatile=*/true,
+                         /*isNonTemporal=*/false, /*Alignment=*/0);
+  }
+
   return Chain;
 }
 

diff --git a/test/CodeGen/WinEH/cppeh-catch-unwind.ll b/test/CodeGen/WinEH/cppeh-catch-unwind.ll
index 055a3ad0dcaff617d4eef221475c463aea881de8..92f67479f9398ab5450efddaef3d32b79696430b 100644 (file)
--- a/test/CodeGen/WinEH/cppeh-catch-unwind.ll
+++ b/test/CodeGen/WinEH/cppeh-catch-unwind.ll
@@ -33,13 +33,10 @@ $"\01??_R0H@8" = comdat any
 
 ; CHECK-LABEL: define void @"\01?test@@YAXXZ"() #0 {
 ; CHECK: entry:
-; CHECK:   [[UNWIND_HELP:\%.+]] = alloca i64
 ; CHECK:   [[OBJ_PTR:\%.+]] = alloca %class.SomeClass
 ; CHECK:   [[TMP0:\%.+]] = alloca i32, align 4
 ; CHECK:   [[TMP1:\%.+]] = alloca i32, align 4
 ; CHECK:   call void (...)* @llvm.frameescape(i32* [[TMP1]], %class.SomeClass* [[OBJ_PTR]], i32* [[TMP0]])
-; CHECK:   [[UNWIND_HELP_i8:\%.+]] = bitcast i64* [[UNWIND_HELP]] to i8*
-; CHECK:   call void @llvm.eh.unwindhelp(i8* [[UNWIND_HELP_i8]])
 ; CHECK:   %call = invoke %class.SomeClass* @"\01??0SomeClass@@QEAA@XZ"(%class.SomeClass* %obj)
 ; CHECK:           to label %invoke.cont unwind label %[[LPAD_LABEL:lpad[0-9]+]]
 

diff --git a/test/CodeGen/WinEH/cppeh-multi-catch.ll b/test/CodeGen/WinEH/cppeh-multi-catch.ll
index 29b342a824ed51ef193157d4acc3de44fda8bb37..a7bd0b86f09d2826a350bb534585ca5daee9760e 100644 (file)
--- a/test/CodeGen/WinEH/cppeh-multi-catch.ll
+++ b/test/CodeGen/WinEH/cppeh-multi-catch.ll
@@ -47,14 +47,10 @@ $"\01??_R0?AVSomeClass@@@8" = comdat any
 
 ; CHECK: define void @"\01?test@@YAXXZ"() #0 {
 ; CHECK: entry:
-; CHECK:   [[UNWINDHELP:\%.+]] = alloca i64
 ; CHECK:   [[OBJ_PTR:\%.+]] = alloca %class.SomeClass*, align 8
 ; CHECK:   [[LL_PTR:\%.+]] = alloca i64, align 8
 ; CHECK:   [[I_PTR:\%.+]] = alloca i32, align 4
 ; CHECK:   call void (...)* @llvm.frameescape(i32* [[I_PTR]], i64* [[LL_PTR]], %class.SomeClass** [[OBJ_PTR]])
-; CHECK:   store volatile i64 -2, i64* [[UNWINDHELP]]
-; CHECK:   [[TMP:\%.+]] = bitcast i64* [[UNWINDHELP]] to i8*
-; CHECK:   call void @llvm.eh.unwindhelp(i8* [[TMP]])
 ; CHECK:   invoke void @"\01?may_throw@@YAXXZ"()
 ; CHECK:           to label %invoke.cont unwind label %[[LPAD_LABEL:lpad[0-9]+]]
 

diff --git a/test/CodeGen/WinEH/cppeh-prepared-catch.ll b/test/CodeGen/WinEH/cppeh-prepared-catch.ll
index c05a202c3a86e4ab53829fdc53dea722f8ac11a6..3bc864833e114e3a519050edae9235ca60b9abb5 100644 (file)
--- a/test/CodeGen/WinEH/cppeh-prepared-catch.ll
+++ b/test/CodeGen/WinEH/cppeh-prepared-catch.ll
@@ -33,8 +33,8 @@ $"\01??_R0H@8" = comdat any
 define internal i8* @"\01?f@@YAXXZ.catch"(i8*, i8*) #4 {
 entry:
   %.i8 = call i8* @llvm.framerecover(i8* bitcast (void ()* @"\01?f@@YAXXZ" to i8*), i8* %1, i32 0)
-  %2 = bitcast i8* %.i8 to i32**
-  %3 = bitcast i32** %2 to i8*
+  %bc2 = bitcast i8* %.i8 to i32**
+  %bc3 = bitcast i32** %bc2 to i8*
   invoke void @"\01?may_throw@@YAXXZ"()
           to label %invoke.cont2 unwind label %lpad1
 
@@ -42,7 +42,7 @@ invoke.cont2:                                     ; preds = %entry
   ret i8* blockaddress(@"\01?f@@YAXXZ", %try.cont)
 
 lpad1:                                            ; preds = %entry
-  %4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+  %lp4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
           cleanup
           catch %eh.CatchHandlerType* @llvm.eh.handlertype.N.0
   %recover = call i8* (...)* @llvm.eh.actions(i32 1, i8* bitcast (%eh.CatchHandlerType* @llvm.eh.handlertype.N.0 to i8*), i32 1, i8* (i8*, i8*)* @"\01?f@@YAXXZ.catch1")
@@ -50,8 +50,6 @@ lpad1:                                            ; preds = %entry
 }
 
 ; CHECK-LABEL: "?f@@YAXXZ.catch":
-; CHECK: ".L?f@@YAXXZ.catch$parent_frame_offset" = 56
-; CHECK:         movq    %rdx, 56(%rsp)
 ; CHECK:        .seh_handlerdata
 ; CHECK:        .long   ("$cppxdata$?f@@YAXXZ")@IMGREL
 
@@ -81,15 +79,11 @@ lpad:                                             ; preds = %entry
 
 define void @"\01?f@@YAXXZ"() #0 {
 entry:
-  %unwindhelp = alloca i64
   %exn.slot = alloca i8*
   %ehselector.slot = alloca i32
   %0 = alloca i32*, align 8
   %1 = alloca double, align 8
   call void (...)* @llvm.frameescape(i32** %0, double* %1)
-  store volatile i64 -2, i64* %unwindhelp
-  %2 = bitcast i64* %unwindhelp to i8*
-  call void @llvm.eh.unwindhelp(i8* %2)
   invoke void @"\01?may_throw@@YAXXZ"()
           to label %invoke.cont unwind label %lpad2
 
@@ -97,7 +91,7 @@ invoke.cont:                                      ; preds = %entry
   br label %try.cont
 
 lpad2:                                            ; preds = %entry
-  %3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+  %2 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
           catch %eh.CatchHandlerType* @llvm.eh.handlertype.H.8
           catch %eh.CatchHandlerType* @llvm.eh.handlertype.N.0
   %recover = call i8* (...)* @llvm.eh.actions(i32 1, i8* bitcast (%eh.CatchHandlerType* @llvm.eh.handlertype.H.8 to i8*), i32 0, i8* (i8*, i8*)* @"\01?f@@YAXXZ.catch", i32 1, i8* bitcast (%eh.CatchHandlerType* @llvm.eh.handlertype.N.0 to i8*), i32 1, i8* (i8*, i8*)* @"\01?f@@YAXXZ.catch1")
@@ -108,7 +102,7 @@ try.cont:                                         ; preds = %lpad2, %invoke.cont
           to label %try.cont8 unwind label %lpad1
 
 lpad1:
-  %4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
+  %3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
           catch %eh.CatchHandlerType* @llvm.eh.handlertype.N.0
   %recover2 = call i8* (...)* @llvm.eh.actions(i32 1, i8* bitcast (%eh.CatchHandlerType* @llvm.eh.handlertype.N.0 to i8*), i32 1, i8* (i8*, i8*)* @"\01?f@@YAXXZ.catch1")
   indirectbr i8* %recover2, [label %try.cont8]
@@ -128,7 +122,7 @@ try.cont8:                                        ; preds = %lpad2, %try.cont
 ; CHECK-NEXT:        .long   ("$tryMap$?f@@YAXXZ")@IMGREL
 ; CHECK-NEXT:        .long   3
 ; CHECK-NEXT:        .long   ("$ip2state$?f@@YAXXZ")@IMGREL
-; CHECK-NEXT:        .long   64
+; CHECK-NEXT:        .long   32
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:"$stateUnwindMap$?f@@YAXXZ":
@@ -194,9 +188,6 @@ declare void @llvm.frameescape(...) #3
 ; Function Attrs: nounwind readnone
 declare i8* @llvm.framerecover(i8*, i8*, i32) #2
 
-; Function Attrs: nounwind
-declare void @llvm.eh.unwindhelp(i8*) #3
-
 declare void @llvm.donothing(...)
 
 attributes #0 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" "wineh-parent"="\ 1?f@@YAXXZ" }

diff --git a/test/CodeGen/WinEH/cppeh-prepared-cleanups.ll b/test/CodeGen/WinEH/cppeh-prepared-cleanups.ll
index 0a76a22208c2e9c8ac2a4daa62bc8d34b6f12c63..df6b5f3be231d8564cea89cf0ed1af15603f75e0 100644 (file)
--- a/test/CodeGen/WinEH/cppeh-prepared-cleanups.ll
+++ b/test/CodeGen/WinEH/cppeh-prepared-cleanups.ll
@@ -38,7 +38,7 @@ $_TI1H = comdat any
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   ("$ip2state$?test1@@YAXXZ")@IMGREL
-; CHECK-NEXT:        .long   64
+; CHECK-NEXT:        .long   32
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:"$stateUnwindMap$?test1@@YAXXZ":
@@ -98,7 +98,7 @@ entry:
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   ("$ip2state$?test2@@YAX_N@Z")@IMGREL
-; CHECK-NEXT:        .long   64
+; CHECK-NEXT:        .long   40
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:"$stateUnwindMap$?test2@@YAX_N@Z":
@@ -117,8 +117,6 @@ entry:
 ; CHECK-NEXT:        .long   0
 
 define void @"\01?test2@@YAX_N@Z"(i1 zeroext %b) #2 {
-entry:
-  %unwindhelp = alloca i64
   %b.addr = alloca i8, align 1
   %s = alloca %struct.S, align 1
   %exn.slot = alloca i8*
@@ -126,10 +124,7 @@ entry:
   %s1 = alloca %struct.S, align 1
   %frombool = zext i1 %b to i8
   store i8 %frombool, i8* %b.addr, align 1
-  %0 = bitcast i64* %unwindhelp to i8*
-  store volatile i64 -2, i64* %unwindhelp
   call void (...)* @llvm.frameescape(%struct.S* %s, %struct.S* %s1)
-  call void @llvm.eh.unwindhelp(i8* %0)
   call void @"\01?may_throw@@YAXXZ"()
   invoke void @"\01?may_throw@@YAXXZ"()
           to label %invoke.cont unwind label %lpad1