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[WinEH] Create a separate MBB for funclet prologues

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Our current emission strategy is to emit the funclet prologue in the
CatchPad's normal destination.  This is problematic because
intra-funclet control flow to the normal destination is not erroneous
and results in us reevaluating the prologue if said control flow is
taken.

Instead, use the CatchPad's location for the funclet prologue.  This
correctly models our desire to have unwind edges evaluate the prologue
but edges to the normal destination result in typical control flow.

Differential Revision: http://reviews.llvm.org/D13424

llvm-svn: 249483
This commit is contained in:
David Majnemer 2015-10-06 23:31:59 +00:00
parent 7d1f4ff326
commit ccf132c096
9 changed files with 244 additions and 34 deletions
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7
lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
View File

@ -216,14 +216,17 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
// are really data, and no instructions can live here.
if (BB->isEHPad()) {
const Instruction *I = BB->getFirstNonPHI();
// FIXME: Don't mark SEH functions without __finally blocks as having
// funclets.
if (!isa<LandingPadInst>(I))
MMI.setHasEHFunclets(true);
if (isa<CatchPadInst>(I) || isa<CatchEndPadInst>(I) ||
isa<CleanupEndPadInst>(I)) {
if (isa<CatchEndPadInst>(I) || isa<CleanupEndPadInst>(I)) {
assert(&*BB->begin() == I &&
"WinEHPrepare failed to remove PHIs from imaginary BBs");
continue;
}
if (isa<CatchPadInst>(I) || isa<CleanupPadInst>(I))
assert(&*BB->begin() == I && "WinEHPrepare failed to demote PHIs");
}
MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(BB);

46
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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@ -1160,7 +1160,35 @@ SDValue SelectionDAGBuilder::getValueImpl(const Value *V) {
}
void SelectionDAGBuilder::visitCatchPad(const CatchPadInst &I) {
llvm_unreachable("should never codegen catchpads");
auto Pers = classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
bool IsMSVCCXX = Pers == EHPersonality::MSVC_CXX;
bool IsSEH = isAsynchronousEHPersonality(Pers);
MachineBasicBlock *CatchPadMBB = FuncInfo.MBB;
// In MSVC C++, catchblocks are funclets and need prologues.
if (IsMSVCCXX)
CatchPadMBB->setIsEHFuncletEntry();
MachineBasicBlock *NormalDestMBB = FuncInfo.MBBMap[I.getNormalDest()];
// Update machine-CFG edge.
FuncInfo.MBB->addSuccessor(NormalDestMBB);
// CatchPads in SEH are not funclets, they are merely markers which indicate
// where to insert register restoration code.
if (IsSEH) {
DAG.setRoot(DAG.getNode(ISD::CATCHRET, getCurSDLoc(), MVT::Other,
getControlRoot(), DAG.getBasicBlock(NormalDestMBB),
DAG.getBasicBlock(FuncInfo.MF->begin())));
return;
}
// If this is not a fall-through branch or optimizations are switched off,
// emit the branch.
if (NormalDestMBB != NextBlock(CatchPadMBB) ||
TM.getOptLevel() == CodeGenOpt::None)
DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(), MVT::Other,
getControlRoot(),
DAG.getBasicBlock(NormalDestMBB)));
}
void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
@ -1168,6 +1196,18 @@ void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
MachineBasicBlock *TargetMBB = FuncInfo.MBBMap[I.getSuccessor()];
FuncInfo.MBB->addSuccessor(TargetMBB);
auto Pers = classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
bool IsSEH = isAsynchronousEHPersonality(Pers);
if (IsSEH) {
// If this is not a fall-through branch or optimizations are switched off,
// emit the branch.
if (TargetMBB != NextBlock(FuncInfo.MBB) ||
TM.getOptLevel() == CodeGenOpt::None)
DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(), MVT::Other,
getControlRoot(), DAG.getBasicBlock(TargetMBB)));
return;
}
// Figure out the funclet membership for the catchret's successor.
// This will be used by the FuncletLayout pass to determine how to order the
// BB's.
@ -1225,8 +1265,8 @@ findUnwindDestinations(FunctionLoweringInfo &FuncInfo,
break;
} else if (const auto *CPI = dyn_cast<CatchPadInst>(Pad)) {
// Add the catchpad handler to the possible destinations.
UnwindDests.push_back(FuncInfo.MBBMap[CPI->getNormalDest()]);
// In MSVC C++ and CoreCLR, catchblocks are funclets and need prologues.
UnwindDests.push_back(FuncInfo.MBBMap[EHPadBB]);
// In MSVC C++, catchblocks are funclets and need prologues.
if (IsMSVCCXX || IsCoreCLR)
UnwindDests.back()->setIsEHFuncletEntry();
EHPadBB = CPI->getUnwindDest();

5
lib/CodeGen/WinEHPrepare.cpp
View File

@ -2612,7 +2612,7 @@ static void addTryBlockMapEntry(WinEHFuncInfo &FuncInfo, int TryLow,
else
HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue();
HT.Handler = CPI->getNormalDest();
HT.Handler = CPI->getParent();
HT.CatchObjRecoverIdx = -2;
if (isa<ConstantPointerNull>(CPI->getArgOperand(2)))
HT.CatchObj.Alloca = nullptr;
@ -2770,8 +2770,7 @@ static void calculateExplicitSEHStateNumbers(WinEHFuncInfo &FuncInfo,
const Function *Filter = dyn_cast<Function>(FilterOrNull);
assert((Filter || FilterOrNull->isNullValue()) &&
"unexpected filter value");
int TryState =
addSEHExcept(FuncInfo, ParentState, Filter, CPI->getNormalDest());
int TryState = addSEHExcept(FuncInfo, ParentState, Filter, CatchPadBB);
// Everything in the __try block uses TryState as its parent state.
FuncInfo.EHPadStateMap[CPI] = TryState;

21
test/CodeGen/X86/funclet-layout.ll
View File

@ -93,13 +93,14 @@ unreachable: ; preds = %catch, %entry
; CHECK: # %try.cont.5
; CHECK: retq
; The inner catch funclet contains %catch.3
; CHECK: # %catch.3
; CHECK: retq
; The outer catch funclet contains %catch.dispatch
; CHECK: # %catch.dispatch{{$}}
; CHECK: callq _CxxThrowException
; CHECK: # %unreachable
; CHECK: ud2
; The outer catch funclet contains %catch and %try.cont
; CHECK: # %catch{{$}}
; CHECK: # %try.cont{{$}}
; The inner catch funclet contains %catch.dispatch.1
; CHECK: # %catch.dispatch.1
; CHECK: retq
@ -149,13 +150,13 @@ exit_two:
; CHECK-NOT: # exit_two
; CHECK: ud2
; The catch(int) funclet contains %catch.2
; CHECK: # %catch.2
; The catch(...) funclet contains %catch.dispatch
; CHECK: # %catch.dispatch{{$}}
; CHECK: callq exit
; CHECK: ud2
; The catch(...) funclet contains %catch
; CHECK: # %catch{{$}}
; The catch(int) funclet contains %catch.dispatch.1
; CHECK: # %catch.dispatch.1
; CHECK: callq exit
; CHECK: ud2

6
test/CodeGen/X86/seh-catchpad.ll
View File

@ -112,7 +112,7 @@ ehcleanup.end: ; preds = %ehcleanup
; CHECK: addq $48, %rsp
; CHECK: popq %rbp
; CHECK: retq
; CHECK: .LBB1_[[except1bb:[0-9]+]]: # %__except
; CHECK: .LBB1_[[except1bb:[0-9]+]]: # %catch.dispatch
; CHECK: .Ltmp2:
; CHECK: movl $1, %ecx
; CHECK: xorl %edx, %edx
@ -120,7 +120,9 @@ ehcleanup.end: ; preds = %ehcleanup
; CHECK: .Ltmp3:
; CHECK: callq "?fin$0@0@main@@"
; CHECK: jmp .LBB1_[[epilogue]]
; CHECK: .LBB1_[[except2bb:[0-9]+]]: # %__except.ret
; CHECK: .LBB1_[[except2bb:[0-9]+]]: # %catch.dispatch.7
; CHECK: jmp .LBB1_7
; CHECK: # %__except.9
; CHECK: leaq "??_C@_06IBDBCMGJ@caught?$AA@"(%rip), %rcx
; CHECK: callq puts
; CHECK: jmp .LBB1_[[epilogue]]

4
test/CodeGen/X86/win-catchpad-csrs.ll
View File

@ -72,7 +72,7 @@ catchendblock: ; preds = %catch,
; X86: jmp [[contbb]]
; X86: "?catch$[[catch1bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X86: LBB0_[[catch1bb]]: # %catch{{$}}
; X86: LBB0_[[catch1bb]]: # %catch.dispatch{{$}}
; X86: pushl %ebp
; X86-NOT: pushl
; X86: subl $16, %esp
@ -119,7 +119,7 @@ catchendblock: ; preds = %catch,
; X64: retq
; X64: "?catch$[[catch1bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X64: LBB0_[[catch1bb]]: # %catch{{$}}
; X64: LBB0_[[catch1bb]]: # %catch.dispatch{{$}}
; X64: movq %rdx, 16(%rsp)
; X64: pushq %rbp
; X64: .seh_pushreg 5

158
test/CodeGen/X86/win-catchpad.ll
View File

@ -25,6 +25,7 @@ $"\01??_R0H@8" = comdat any
declare void @f(i32 %p, i32* %l)
declare i1 @getbool()
declare i32 @__CxxFrameHandler3(...)
define i32 @try_catch_catch() personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
@ -74,24 +75,24 @@ catchendblock: ; preds = %catch, %catch.2, %c
; X86: retl
; FIXME: These should be de-duplicated.
; X86: [[restorebb1:LBB0_[0-9]+]]: # %invoke.cont.2
; X86: movl -16(%ebp), %esp
; X86: addl $12, %ebp
; X86: jmp [[contbb]]
; X86: [[restorebb2:LBB0_[0-9]+]]: # %invoke.cont.3
; X86: movl -16(%ebp), %esp
; X86: addl $12, %ebp
; X86: jmp [[contbb]]
; X86: [[restorebb1:LBB0_[0-9]+]]: # %invoke.cont.2
; X86: movl -16(%ebp), %esp
; X86: addl $12, %ebp
; X86: jmp [[contbb]]
; X86: "?catch$[[catch1bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X86: LBB0_[[catch1bb]]: # %catch{{$}}
; X86: LBB0_[[catch1bb]]: # %catch.dispatch{{$}}
; X86: pushl %ebp
; X86: subl $8, %esp
; X86: addl $12, %ebp
; X86: leal -[[local_offs]](%ebp), %[[addr_reg:[a-z]+]]
; X86: movl -32(%ebp), %[[e_reg:[a-z]+]]
; X86: movl $1, -{{[0-9]+}}(%ebp)
; X86: leal -[[local_offs]](%ebp), %[[addr_reg:[a-z]+]]
; X86-DAG: movl %[[addr_reg]], 4(%esp)
; X86-DAG: movl %[[e_reg]], (%esp)
; X86: calll _f
@ -101,12 +102,12 @@ catchendblock: ; preds = %catch, %catch.2, %c
; X86-NEXT: retl
; X86: "?catch$[[catch2bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X86: LBB0_[[catch2bb]]: # %catch.2{{$}}
; X86: LBB0_[[catch2bb]]: # %catch.dispatch.2{{$}}
; X86: pushl %ebp
; X86: subl $8, %esp
; X86: addl $12, %ebp
; X86: movl $1, -{{[0-9]+}}(%ebp)
; X86: leal -[[local_offs]](%ebp), %[[addr_reg:[a-z]+]]
; X86: movl $1, -{{[0-9]+}}(%ebp)
; X86-DAG: movl %[[addr_reg]], 4(%esp)
; X86-DAG: movl $3, (%esp)
; X86: calll _f
@ -145,7 +146,7 @@ catchendblock: ; preds = %catch, %catch.2, %c
; X64: retq
; X64: "?catch$[[catch1bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X64: LBB0_[[catch1bb]]: # %catch{{$}}
; X64: LBB0_[[catch1bb]]: # %catch.dispatch{{$}}
; X64: movq %rdx, 16(%rsp)
; X64: pushq %rbp
; X64: .seh_pushreg 5
@ -163,7 +164,7 @@ catchendblock: ; preds = %catch, %catch.2, %c
; X64-NEXT: retq
; X64: "?catch$[[catch2bb:[0-9]+]]@?0?try_catch_catch@4HA":
; X64: LBB0_[[catch2bb]]: # %catch.2{{$}}
; X64: LBB0_[[catch2bb]]: # %catch.dispatch.2{{$}}
; X64: movq %rdx, 16(%rsp)
; X64: pushq %rbp
; X64: .seh_pushreg 5
@ -221,3 +222,138 @@ catchendblock: ; preds = %catch, %catch.2, %c
; X64-NEXT: .long 1
; X64-NEXT: .long .Ltmp3@IMGREL+1
; X64-NEXT: .long -1
define i32 @branch_to_normal_dest() personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
entry:
invoke void @f(i32 1, i32* null)
to label %try.cont unwind label %catch.dispatch
catch.dispatch:
%0 = catchpad [i8* null, i32 64, i8* null]
to label %catch unwind label %catchendblock
catch:
%V = call i1 @getbool()
br i1 %V, label %catch, label %catch.done
catch.done:
catchret %0 to label %try.cont
try.cont:
ret i32 0
catchendblock:
catchendpad unwind to caller
}
; X86-LABEL: _branch_to_normal_dest:
; X86: calll _f
; X86: [[contbb:LBB1_[0-9]+]]: # %try.cont
; X86: retl
; X86: [[restorebb:LBB1_[0-9]+]]: # %catch.done
; X86: movl -16(%ebp), %esp
; X86: addl $12, %ebp
; X86: jmp [[contbb]]
; X86: "?catch$[[catchdispbb:[0-9]+]]@?0?branch_to_normal_dest@4HA":
; X86: LBB1_[[catchdispbb]]: # %catch.dispatch{{$}}
; X86: pushl %ebp
; X86: subl $8, %esp
; X86: addl $12, %ebp
; X86: LBB1_[[catchbb:[0-9]+]]: # %catch
; X86: movl $-1, -16(%ebp)
; X86: calll _getbool
; X86: testb $1, %al
; X86: jne LBB1_[[catchbb]]
; X86: # %catch.done
; X86-NEXT: movl $[[restorebb]], %eax
; X86-NEXT: addl $8, %esp
; X86-NEXT: popl %ebp
; X86-NEXT: retl
; X86: L__ehtable$branch_to_normal_dest:
; X86: $handlerMap$0$branch_to_normal_dest:
; X86-NEXT: .long 64
; X86-NEXT: .long 0
; X86-NEXT: .long 0
; X86-NEXT: .long "?catch$[[catchdispbb]]@?0?branch_to_normal_dest@4HA"
; X64-LABEL: branch_to_normal_dest:
; X64: # %entry
; X64: pushq %rbp
; X64: .seh_pushreg 5
; X64: subq $48, %rsp
; X64: .seh_stackalloc 48
; X64: leaq 48(%rsp), %rbp
; X64: .seh_setframe 5, 48
; X64: .seh_endprologue
; X64: .Ltmp[[before_call:[0-9]+]]:
; X64: callq f
; X64: .Ltmp[[after_call:[0-9]+]]:
; X64: [[contbb:\.LBB1_[0-9]+]]: # %try.cont
; X64: addq $48, %rsp
; X64: popq %rbp
; X64: retq
; X64: "?catch$[[catchbb:[0-9]+]]@?0?branch_to_normal_dest@4HA":
; X64: LBB1_[[catchbb]]: # %catch.dispatch{{$}}
; X64: movq %rdx, 16(%rsp)
; X64: pushq %rbp
; X64: .seh_pushreg 5
; X64: subq $32, %rsp
; X64: .seh_stackalloc 32
; X64: leaq 48(%rdx), %rbp
; X64: .seh_endprologue
; X64: .LBB1_[[normal_dest_bb:[0-9]+]]: # %catch
; X64: callq getbool
; X64: testb $1, %al
; X64: jne .LBB1_[[normal_dest_bb]]
; X64: # %catch.done
; X64: leaq [[contbb]](%rip), %rax
; X64-NEXT: addq $32, %rsp
; X64-NEXT: popq %rbp
; X64-NEXT: retq
; X64-LABEL: $cppxdata$branch_to_normal_dest:
; X64-NEXT: .long 429065506
; X64-NEXT: .long 2
; X64-NEXT: .long ($stateUnwindMap$branch_to_normal_dest)@IMGREL
; X64-NEXT: .long 1
; X64-NEXT: .long ($tryMap$branch_to_normal_dest)@IMGREL
; X64-NEXT: .long 3
; X64-NEXT: .long ($ip2state$branch_to_normal_dest)@IMGREL
; X64-NEXT: .long 40
; X64-NEXT: .long 0
; X64-NEXT: .long 1
; X64-LABEL: $stateUnwindMap$branch_to_normal_dest:
; X64-NEXT: .long -1
; X64-NEXT: .long 0
; X64-NEXT: .long -1
; X64-NEXT: .long 0
; X64-LABEL: $tryMap$branch_to_normal_dest:
; X64-NEXT: .long 0
; X64-NEXT: .long 0
; X64-NEXT: .long 1
; X64-NEXT: .long 1
; X64-NEXT: .long ($handlerMap$0$branch_to_normal_dest)@IMGREL
; X64-LABEL: $handlerMap$0$branch_to_normal_dest:
; X64-NEXT: .long 64
; X64-NEXT: .long 0
; X64-NEXT: .long 0
; X64-NEXT: .long "?catch$[[catchbb]]@?0?branch_to_normal_dest@4HA"@IMGREL
; X64-NEXT: .long 56
; X64-LABEL: $ip2state$branch_to_normal_dest:
; X64-NEXT: .long .Lfunc_begin1@IMGREL
; X64-NEXT: .long -1
; X64-NEXT: .long .Ltmp[[before_call]]@IMGREL
; X64-NEXT: .long 0
; X64-NEXT: .long .Ltmp[[after_call]]@IMGREL+1
; X64-NEXT: .long -1

2
test/CodeGen/X86/win-funclet-cfi.ll
View File

@ -70,7 +70,7 @@ declare i32 @__CxxFrameHandler3(...)
; CHECK: "?catch$[[catch:[0-9]+]]@?0??f@@YAXXZ@4HA":
; CHECK: .seh_proc "?catch$[[catch]]@?0??f@@YAXXZ@4HA"
; CHECK-NEXT: .seh_handler __CxxFrameHandler3, @unwind, @except
; CHECK: LBB0_[[catch]]: # %catch{{$}}
; CHECK: LBB0_[[catch]]: # %catch.dispatch{{$}}
; Emit CFI for pushing RBP.
; CHECK: movq %rdx, 16(%rsp)

29
test/CodeGen/X86/win32-seh-catchpad.ll
View File

@ -197,6 +197,35 @@ entry:
ret i32 1
}
define void @code_in_catchpad() #0 personality i8* bitcast (i32 (...)* @_except_handler3 to i8*) {
entry:
invoke void @f(i32 1) #3
to label %__except unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%0 = catchpad [i8* bitcast (i32 ()* @try_except_filter_catchall to i8*)] to label %__except.ret unwind label %catchendblock
__except.ret: ; preds = %catch.dispatch
call void @f(i32 2)
catchret %0 to label %__except
__except:
ret void
catchendblock: ; preds = %catch.dispatch
catchendpad unwind to caller
}
; CHECK-LABEL: _code_in_catchpad:
; CHECK: # %catch.dispatch
; CHECK-NEXT: movl -24(%ebp), %esp
; CHECK-NEXT: addl $12, %ebp
; CHECK: # %__except.ret
; CHECK-NEXT: movl $-1, -16(%ebp)
; CHECK-NEXT: movl $2, (%esp)
; CHECK-NEXT: calll _f
; Function Attrs: nounwind readnone
declare i8* @llvm.frameaddress(i32) #1