[llvm] 494abe1 - [AArch64] Change AArch64 Windows EH UnwindHelp object to be a fixed object
Eli Friedman via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 31 14:21:58 PDT 2020
Author: Daniel Frampton
Date: 2020-03-31T14:21:21-07:00
New Revision: 494abe139a9aab991582f1b3f3370b99b252944c
URL: https://github.com/llvm/llvm-project/commit/494abe139a9aab991582f1b3f3370b99b252944c
DIFF: https://github.com/llvm/llvm-project/commit/494abe139a9aab991582f1b3f3370b99b252944c.diff
LOG: [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
Added:
llvm/test/CodeGen/AArch64/wineh-unwindhelp-via-fp.ll
Modified:
llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
llvm/test/CodeGen/AArch64/seh-finally.ll
llvm/test/CodeGen/AArch64/wineh-try-catch-cbz.ll
llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll
llvm/test/CodeGen/AArch64/wineh-try-catch.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index a8fdf23a9a5d..f16c96ed70ec 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -216,6 +216,24 @@ AArch64FrameLowering::getStackIDForScalableVectors() const {
return TargetStackID::SVEVector;
}
+/// 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);
+ }
+}
+
/// Returns the size of the entire SVE stackframe (calleesaves + spills).
static StackOffset getSVEStackSize(const MachineFunction &MF) {
const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
@@ -995,10 +1013,7 @@ 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.
@@ -1477,10 +1492,7 @@ 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;
@@ -1706,7 +1718,9 @@ static StackOffset getFPOffset(const MachineFunction &MF, int64_t 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);
unsigned FPAdjust = isTargetDarwin(MF)
? 16 : AFI->getCalleeSavedStackSize(MF.getFrameInfo());
return {ObjectOffset + FixedObject + FPAdjust, MVT::i8};
@@ -2659,9 +2673,14 @@ 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
+ 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;
@@ -3073,10 +3092,14 @@ 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
diff --git a/llvm/test/CodeGen/AArch64/seh-finally.ll b/llvm/test/CodeGen/AArch64/seh-finally.ll
index 66558c90a79c..dbc6c4b0804b 100644
--- a/llvm/test/CodeGen/AArch64/seh-finally.ll
+++ b/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$frame_escape_0, -8
; CHECK: ldur w0, [x29, #-8]
; CHECK: bl foo
@@ -87,13 +87,13 @@ define void @stack_realign() #0 personality i8* bitcast (i32 (...)* @__C_specifi
entry:
; CHECK-LABEL: stack_realign
; CHECK: mov x29, sp
-; CHECK: sub x9, sp, #64
+; CHECK: sub x9, sp, #16
; CHECK: and sp, x9, #0xffffffffffffffe0
; CHECK: mov x19, sp
; CHECK: mov x0, #-2
-; CHECK: stur x0, [x19, #16]
-; CHECK: .set .Lstack_realign$frame_escape_0, 32
-; CHECK: ldr w0, [x19, #32]
+; CHECK: stur x0, [x29, #32]
+; 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: mov x29, sp
-; 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, #32]
; CHECK: .set .Lvla_and_realign$frame_escape_0, 32
-; CHECK: str w0, [x29, #28]
-; CHECK: ldr w8, [x29, #28]
+; CHECK: str w0, [x29, #44]
+; CHECK: ldr w8, [x29, #44]
; CHECK: mov x9, sp
-; CHECK: str x9, [x19, #24]
-; CHECK: str x8, [x19, #16]
+; CHECK: str x9, [x29, #24]
+; CHECK: str x8, [x19, #24]
; CHECK: ldr w0, [x19, #32]
; CHECK: bl foo
diff --git a/llvm/test/CodeGen/AArch64/wineh-try-catch-cbz.ll b/llvm/test/CodeGen/AArch64/wineh-try-catch-cbz.ll
index d84c07f8bc1a..cbed64ab99e3 100644
--- a/llvm/test/CodeGen/AArch64/wineh-try-catch-cbz.ll
+++ b/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"
diff --git a/llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll b/llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll
index b10a0f3033a0..a66ec10748e7 100644
--- a/llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll
+++ b/llvm/test/CodeGen/AArch64/wineh-try-catch-realign.ll
@@ -12,7 +12,7 @@
; CHECK: stp x29, x30, [sp, #-32]!
; CHECK-NEXT: str x28, [sp, #16]
; CHECK-NEXT: str x19, [sp, #24]
-; CHECK-NEXT: add x0, x19, #64
+; CHECK-NEXT: add x0, x19, #0
; CHECK-NEXT: mov w1, wzr
; CHECK-NEXT: bl "?bb@@YAXPEAHH at Z"
; CHECK-NEXT: adrp x0, .LBB0_1
diff --git a/llvm/test/CodeGen/AArch64/wineh-try-catch.ll b/llvm/test/CodeGen/AArch64/wineh-try-catch.ll
index 3ae2df37efe4..73909825d377 100644
--- a/llvm/test/CodeGen/AArch64/wineh-try-catch.ll
+++ b/llvm/test/CodeGen/AArch64/wineh-try-catch.ll
@@ -11,11 +11,11 @@
; 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: stp x29, x30, [sp, #-48]!
+; CHECK: stp x29, x30, [sp, #-64]!
; CHECK: str x28, [sp, #16]
; CHECK: str x21, [sp, #24]
; CHECK: stp x19, x20, [sp, #32]
@@ -23,7 +23,7 @@
; CHECK: sub sp, sp, #624
; CHECK: mov x19, sp
; CHECK: mov x0, #-2
-; CHECK: stur x0, [x19]
+; CHECK: stur x0, [x29, #48]
; 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$?func@@YAHXZ":
; CHECK-NEXT: .word 429065506 ; MagicNumber
; CHECK-NEXT: .word 2 ; MaxState
@@ -81,7 +81,7 @@
; CHECK-NEXT: .word ("$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 [
@@ -91,7 +91,7 @@
; 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, #-48]!
+; UNWIND-NEXT: ; stp x29, x30, [sp, #-64]!
; UNWIND-NEXT: ; end
; UNWIND: Function: ?catch$2@?0??func@@YAHXZ at 4HA
; UNWIND: Prologue [
diff --git a/llvm/test/CodeGen/AArch64/wineh-unwindhelp-via-fp.ll b/llvm/test/CodeGen/AArch64/wineh-unwindhelp-via-fp.ll
new file mode 100644
index 000000000000..6ec78087020c
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/wineh-unwindhelp-via-fp.ll
@@ -0,0 +1,69 @@
+; RUN: llc -o - %s -mtriple=aarch64-windows | FileCheck %s
+; Check that we allocate the unwind help stack object in a fixed location from fp
+; so that the runtime can find it when handling an exception
+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"
+
+; Check that the store to the unwind help object for func2 is via FP
+; CHECK-LABEL: ?func2@@YAXXZ
+; CHECK: mov x[[#SCRATCH_REG:]], #-2
+; CHECK: stur x[[#SCRATCH_REG:]], [x29, #[[#]]]
+;
+; // struct that requires greater than stack alignment
+; struct alignas(32) A
+; {
+; // data that would be invalid for unwind help (> 0)
+; int _x[4]{42, 42, 42, 42};
+; ~A() {}
+; };
+;
+; // cause us to run the funclet in func2
+; void func3()
+; {
+; throw 1;
+; }
+;
+; // the funclet that ensures we have the unwind help correct
+; void func2()
+; {
+; A a;
+; func3();
+; }
+;
+; // function to ensure we are misaligned in func2
+; void func1()
+; {
+; func2();
+; }
+;
+; // set things up and ensure alignment for func1
+; void test()
+; {
+; try {
+; A a;
+; func1();
+; } catch(...) {}
+; }
+
+%struct.A = type { [4 x i32], [16 x i8] }
+declare dso_local %struct.A* @"??0A@@QEAA at XZ"(%struct.A* returned %0)
+declare dso_local void @"??1A@@QEAA at XZ"(%struct.A* %0)
+declare dso_local i32 @__CxxFrameHandler3(...)
+declare dso_local void @"?func3@@YAXXZ"()
+
+; Function Attrs: noinline optnone uwtable
+define dso_local void @"?func2@@YAXXZ"() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+ %1 = alloca %struct.A, align 32
+ %2 = call %struct.A* @"??0A@@QEAA at XZ"(%struct.A* %1) #3
+ invoke void @"?func3@@YAXXZ"()
+ to label %3 unwind label %4
+
+3: ; preds = %0
+ call void @"??1A@@QEAA at XZ"(%struct.A* %1) #3
+ ret void
+
+4: ; preds = %0
+ %5 = cleanuppad within none []
+ call void @"??1A@@QEAA at XZ"(%struct.A* %1) #3 [ "funclet"(token %5) ]
+ cleanupret from %5 unwind to caller
+}
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