efriedma updated this revision to Diff 522773.
efriedma added a comment.
Herald added a subscriber: arichardson.
Rebased so it builds, and added a couple tests, to unblock anyone wanting to
look at this further. Haven't re-done my runtime testing. Still haven't
addressed all the review comments.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D124642/new/
https://reviews.llvm.org/D124642
Files:
clang/lib/CodeGen/CGException.cpp
clang/lib/CodeGen/CGStmt.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/lib/Sema/SemaStmt.cpp
clang/test/CodeGen/exceptions-seh-finally.c
clang/test/CodeGen/exceptions-seh-leave.c
clang/test/CodeGen/windows-seh-return-finally.c
llvm/include/llvm/IR/Intrinsics.td
llvm/lib/CodeGen/AsmPrinter/WinException.cpp
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/lib/CodeGen/WinEHPrepare.cpp
llvm/lib/IR/Verifier.cpp
llvm/test/CodeGen/X86/seh-return-from-finally.ll
llvm/utils/UpdateTestChecks/common.py
Index: llvm/utils/UpdateTestChecks/common.py
===================================================================
--- llvm/utils/UpdateTestChecks/common.py
+++ llvm/utils/UpdateTestChecks/common.py
@@ -353,7 +353,7 @@
UNUSED_NOTE = 'NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:'
OPT_FUNCTION_RE = re.compile(
- r'^(\s*;\s*Function\sAttrs:\s(?P<attrs>[\w\s():,]+?))?\s*define\s+(?P<funcdef_attrs_and_ret>[^@]*)@(?P<func>[\w.$-]+?)\s*'
+ r'^(\s*;\s*Function\sAttrs:\s(?P<attrs>[\w\s():,]+?))?\s*define\s+(?P<funcdef_attrs_and_ret>[^@]*)@(?P<func>([\w.$-]+?|"[\w.$-?@]+?"))\s*'
r'(?P<args_and_sig>\((\)|(.*?[\w.-]+?)\))[^{]*\{)\n(?P<body>.*?)^\}$',
flags=(re.M | re.S))
Index: llvm/test/CodeGen/X86/seh-return-from-finally.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/seh-return-from-finally.ll
@@ -0,0 +1,237 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --include-generated-funcs --version 2
+; RUN: llc < %s | FileCheck %s
+target triple = "x86_64-unknown-windows-msvc19.20.0"
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @f(i32 noundef %z) #0 personality ptr @__C_specific_handler {
+entry:
+ %z.addr = alloca i32, align 4
+ %retnow = alloca i8, align 1
+ call void (...) @llvm.localescape(ptr %z.addr, ptr %retnow)
+ store i32 %z, ptr %z.addr, align 4
+ store i8 0, ptr %retnow, align 1
+ invoke void @f1() #6
+ to label %invoke.cont unwind label %ehcleanup
+
+invoke.cont: ; preds = %entry
+ %0 = call ptr @llvm.localaddress()
+ invoke void @"?fin$0@0@f@@"(i8 noundef 0, ptr noundef %0)
+ to label %invoke.cont1 unwind label %catch.dispatch
+
+invoke.cont1: ; preds = %invoke.cont
+ br label %__finally.cont
+
+__finally.cont: ; preds = %invoke.cont1
+ %1 = load i8, ptr %retnow, align 1
+ %2 = icmp ne i8 %1, 0
+ br i1 %2, label %if.then4, label %if.end5
+
+ehcleanup: ; preds = %entry
+ %3 = cleanuppad within none []
+ %4 = call ptr @llvm.localaddress()
+ invoke void @"?fin$0@0@f@@"(i8 noundef 1, ptr noundef %4) [ "funclet"(token %3) ]
+ to label %invoke.cont2 unwind label %catch.dispatch
+
+invoke.cont2: ; preds = %ehcleanup
+ %5 = load i8, ptr %retnow, align 1
+ %6 = icmp ne i8 %5, 0
+ br i1 %6, label %if.then, label %if.end
+
+if.then: ; preds = %invoke.cont2
+ invoke void @llvm.seh.localunwind()
+ to label %invoke.cont3 unwind label %catch.dispatch
+
+invoke.cont3: ; preds = %if.then
+ unreachable
+
+if.end: ; preds = %invoke.cont2
+ cleanupret from %3 unwind label %catch.dispatch
+
+catch.dispatch: ; preds = %if.end, %if.then, %ehcleanup, %invoke.cont
+ %7 = catchswitch within none [label %__except.ret] unwind to caller
+
+__except.ret: ; preds = %catch.dispatch
+ %8 = catchpad within %7 [ptr @__IsLocalUnwind]
+ catchret from %8 to label %if.then4
+
+if.then4: ; preds = %__except.ret, %__finally.cont
+ br label %if.end5
+
+if.end5: ; preds = %if.then4, %__finally.cont
+ ret void
+}
+
+declare extern_weak void @__IsLocalUnwind(ptr, ptr)
+
+; Function Attrs: noinline nounwind uwtable
+define internal void @"?fin$0@0@f@@"(i8 noundef %abnormal_termination, ptr noundef %frame_pointer) #1 {
+entry:
+ %frame_pointer.addr = alloca ptr, align 8
+ %abnormal_termination.addr = alloca i8, align 1
+ %z.addr = call ptr @llvm.localrecover(ptr @f, ptr %frame_pointer, i32 0)
+ %retnow = call ptr @llvm.localrecover(ptr @f, ptr %frame_pointer, i32 1)
+ store ptr %frame_pointer, ptr %frame_pointer.addr, align 8
+ store i8 %abnormal_termination, ptr %abnormal_termination.addr, align 1
+ call void @f2()
+ %0 = load i32, ptr %z.addr, align 4
+ %tobool = icmp ne i32 %0, 0
+ br i1 %tobool, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ store i8 1, ptr %retnow, align 1
+ br label %return
+
+if.end: ; preds = %entry
+ call void @f3()
+ br label %return
+
+return: ; preds = %if.end, %if.then
+ ret void
+}
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
+declare ptr @llvm.localrecover(ptr, ptr, i32 immarg) #2
+
+declare dso_local void @f2(...) #3
+
+declare dso_local void @f3(...) #3
+
+declare dso_local void @f1(...) #3
+
+declare dso_local i32 @__C_specific_handler(...)
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
+declare ptr @llvm.localaddress() #2
+
+; Function Attrs: noreturn nounwind
+declare void @llvm.seh.localunwind() #4
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn
+declare void @llvm.localescape(...) #5
+
+attributes #0 = { noinline nounwind optnone uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #1 = { noinline nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #2 = { nocallback nofree nosync nounwind willreturn memory(none) }
+attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #4 = { noreturn nounwind }
+attributes #5 = { nocallback nofree nosync nounwind willreturn }
+attributes #6 = { noinline }
+; CHECK-LABEL: f:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .seh_pushreg %rbp
+; CHECK-NEXT: subq $48, %rsp
+; CHECK-NEXT: .seh_stackalloc 48
+; CHECK-NEXT: leaq {{[0-9]+}}(%rsp), %rbp
+; CHECK-NEXT: .seh_setframe %rbp, 48
+; CHECK-NEXT: .seh_endprologue
+; CHECK-NEXT: .set .Lf$frame_escape_0, -8
+; CHECK-NEXT: .set .Lf$frame_escape_1, -1
+; CHECK-NEXT: movl %ecx, -8(%rbp)
+; CHECK-NEXT: movb $0, -1(%rbp)
+; CHECK-NEXT: .Ltmp0:
+; CHECK-NEXT: callq f1
+; CHECK-NEXT: .Ltmp1:
+; CHECK-NEXT: jmp .LBB0_1
+; CHECK-NEXT: .LBB0_1: # %invoke.cont
+; CHECK-NEXT: .Ltmp6:
+; CHECK-NEXT: xorl %ecx, %ecx
+; CHECK-NEXT: movq %rbp, %rdx
+; CHECK-NEXT: callq "?fin$0@0@f@@"
+; CHECK-NEXT: .Ltmp7:
+; CHECK-NEXT: jmp .LBB0_2
+; CHECK-NEXT: .LBB0_2: # %invoke.cont1
+; CHECK-NEXT: cmpb $0, -1(%rbp)
+; CHECK-NEXT: jne .LBB0_9
+; CHECK-NEXT: jmp .LBB0_10
+; CHECK-NEXT: .Ltmp8: # Block address taken
+; CHECK-NEXT: .LBB0_8: # %__except.ret
+; CHECK-NEXT: jmp .LBB0_9
+; CHECK-NEXT: .LBB0_9: # %if.then4
+; CHECK-NEXT: $ehgcr_0_9:
+; CHECK-NEXT: jmp .LBB0_10
+; CHECK-NEXT: .LBB0_10: # %if.end5
+; CHECK-NEXT: addq $48, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: retq
+; CHECK-NEXT: .seh_handlerdata
+; CHECK-NEXT: .set .Lf$parent_frame_offset, 48
+; CHECK-NEXT: .long (.Llsda_end0-.Llsda_begin0)/16 # Number of call sites
+; CHECK-NEXT: .Llsda_begin0:
+; CHECK-NEXT: .long .Ltmp0@IMGREL # LabelStart
+; CHECK-NEXT: .long .Ltmp1@IMGREL+1 # LabelEnd
+; CHECK-NEXT: .long "?dtor$3@?0?f@4HA"@IMGREL # FinallyFunclet
+; CHECK-NEXT: .long 0 # Null
+; CHECK-NEXT: .long .Ltmp6@IMGREL # LabelStart
+; CHECK-NEXT: .long .Ltmp7@IMGREL+1 # LabelEnd
+; CHECK-NEXT: .long 1 # CatchAll
+; CHECK-NEXT: .long .LBB0_8@IMGREL # ExceptionHandler
+; CHECK-NEXT: .Llsda_end0:
+; CHECK-NEXT: .text
+; CHECK-NEXT: .seh_endproc
+; CHECK-NEXT: .def "?dtor$3@?0?f@4HA";
+; CHECK-NEXT: .scl 3;
+; CHECK-NEXT: .type 32;
+; CHECK-NEXT: .endef
+; CHECK-NEXT: .p2align 4, 0x90
+; CHECK-NEXT: "?dtor$3@?0?f@4HA":
+; CHECK-NEXT: .seh_proc "?dtor$3@?0?f@4HA"
+; CHECK-NEXT: .LBB0_3: # %ehcleanup
+; CHECK-NEXT: movq %rdx, {{[0-9]+}}(%rsp)
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .seh_pushreg %rbp
+; CHECK-NEXT: subq $32, %rsp
+; CHECK-NEXT: .seh_stackalloc 32
+; CHECK-NEXT: leaq 48(%rdx), %rbp
+; CHECK-NEXT: .seh_endprologue
+; CHECK-NEXT: .Ltmp2:
+; CHECK-NEXT: movb $1, %cl
+; CHECK-NEXT: movq %rbp, %rdx
+; CHECK-NEXT: callq "?fin$0@0@f@@"
+; CHECK-NEXT: .Ltmp3:
+; CHECK-NEXT: jmp .LBB0_4
+; CHECK-NEXT: .LBB0_4: # %invoke.cont2
+; CHECK-NEXT: cmpb $0, -1(%rbp)
+; CHECK-NEXT: je .LBB0_7
+; CHECK-NEXT: # %bb.5: # %if.then
+; CHECK-NEXT: .Ltmp4:
+; CHECK-NEXT: leaq -48(%rbp), %rcx
+; CHECK-NEXT: leaq .Ltmp8(%rip), %rdx
+; CHECK-NEXT: callq _local_unwind
+; CHECK-NEXT: .Ltmp5:
+; CHECK-NEXT: jmp .LBB0_6
+; CHECK-NEXT: .LBB0_6: # %invoke.cont3
+; CHECK-NEXT: .LBB0_7: # %if.end
+; CHECK-NEXT: addq $32, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: retq # CLEANUPRET
+; CHECK-NEXT: .Lfunc_end0:
+; CHECK-NEXT: .seh_handlerdata
+; CHECK-NEXT: .text
+; CHECK-NEXT: .seh_endproc
+;
+; CHECK-LABEL: "?fin$0@0@f@@":
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: pushq %rsi
+; CHECK-NEXT: .seh_pushreg %rsi
+; CHECK-NEXT: subq $48, %rsp
+; CHECK-NEXT: .seh_stackalloc 48
+; CHECK-NEXT: .seh_endprologue
+; CHECK-NEXT: movq %rdx, %rsi
+; CHECK-NEXT: movq %rdx, {{[0-9]+}}(%rsp)
+; CHECK-NEXT: movb %cl, {{[0-9]+}}(%rsp)
+; CHECK-NEXT: callq f2
+; CHECK-NEXT: cmpl $0, .Lf$frame_escape_0(%rsi)
+; CHECK-NEXT: je .LBB1_2
+; CHECK-NEXT: # %bb.1: # %if.then
+; CHECK-NEXT: leaq .Lf$frame_escape_1(%rsi), %rax
+; CHECK-NEXT: movb $1, (%rax)
+; CHECK-NEXT: jmp .LBB1_3
+; CHECK-NEXT: .LBB1_2: # %if.end
+; CHECK-NEXT: callq f3
+; CHECK-NEXT: .LBB1_3: # %return
+; CHECK-NEXT: nop
+; CHECK-NEXT: addq $48, %rsp
+; CHECK-NEXT: popq %rsi
+; CHECK-NEXT: retq
+; CHECK-NEXT: .seh_endproc
Index: llvm/lib/IR/Verifier.cpp
===================================================================
--- llvm/lib/IR/Verifier.cpp
+++ llvm/lib/IR/Verifier.cpp
@@ -4824,6 +4824,7 @@
F->getIntrinsicID() == Intrinsic::experimental_patchpoint_i64 ||
F->getIntrinsicID() == Intrinsic::experimental_gc_statepoint ||
F->getIntrinsicID() == Intrinsic::wasm_rethrow ||
+ F->getIntrinsicID() == Intrinsic::seh_localunwind ||
IsAttachedCallOperand(F, CBI, i),
"Cannot invoke an intrinsic other than donothing, patchpoint, "
"statepoint, coro_resume, coro_destroy or clang.arc.attachedcall",
Index: llvm/lib/CodeGen/WinEHPrepare.cpp
===================================================================
--- llvm/lib/CodeGen/WinEHPrepare.cpp
+++ llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -502,6 +502,20 @@
const Function *Filter = dyn_cast<Function>(FilterOrNull);
assert((Filter || FilterOrNull->isNullValue()) &&
"unexpected filter value");
+ // Filters named __IsLocalUnwind are treated specially: we want to catch
+ // unwinds from _local_unwind, but not catchrets in the same funclet.
+ // (They both need to point at the same catchswitch to pass the verifier
+ // checks for nesting.) To make this work, we mess with the state
+ // numbering: the "parent" of any cleanupret pointing to this catchpad is
+ // actually this catchpad's parent.
+ //
+ // Note that _local_unwind looks for unwind table entries for the
+ // catchpad; if there aren't any, it assumes the catchpad doesn't have a
+ // parent.
+ bool IsLocalUnwind =
+ Filter && Filter->getName().startswith("__IsLocalUnwind");
+ if (IsLocalUnwind)
+ Filter = nullptr;
int TryState = addSEHExcept(FuncInfo, ParentState, Filter, CatchPadBB);
// Everything in the __try block uses TryState as its parent state.
@@ -513,7 +527,7 @@
if ((PredBlock = getEHPadFromPredecessor(PredBlock,
CatchSwitch->getParentPad())))
calculateSEHStateNumbers(FuncInfo, PredBlock->getFirstNonPHI(),
- TryState);
+ IsLocalUnwind ? ParentState : TryState);
// Everything in the __except block unwinds to ParentState, just like code
// outside the __try.
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3035,6 +3035,44 @@
DAG.setRoot(DAG.getNode(ISD::INTRINSIC_VOID, getCurSDLoc(), VTs, Ops));
break;
}
+ case Intrinsic::seh_localunwind: {
+ if (!isa<CatchSwitchInst>(EHPadBB->getTerminator())) {
+ report_fatal_error("localunwind doesn't point to catchswitch");
+ }
+ auto *CatchSwitch = cast<CatchSwitchInst>(EHPadBB->getTerminator());
+ if (CatchSwitch->getNumHandlers() == 0) {
+ report_fatal_error("catchswitch with no handler");
+ }
+
+ const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+ TargetLowering::ArgListEntry SP, DestBB;
+ Type *PtrTy = PointerType::getInt8PtrTy(*DAG.getContext());
+ EVT PtrVT = TLI.getPointerTy(DAG.getDataLayout());
+ SP.Node = DAG.getNode(ISD::FRAMEADDR, getCurSDLoc(), PtrVT,
+ DAG.getIntPtrConstant(0, getCurSDLoc()));
+ SP.Ty = PtrTy;
+ // FIXME: Using a BlockAddress here is messy, but there isn't any
+ // node that directly represents taking the address of an MBB.
+ BasicBlock *HandlerBB =
+ const_cast<BasicBlock *>(*CatchSwitch->handler_begin());
+ MachineBasicBlock *HandlerMBB = FuncInfo.MBBMap[HandlerBB];
+ HandlerMBB->setMachineBlockAddressTaken();
+ HandlerMBB->setAddressTakenIRBlock(HandlerBB);
+ DestBB.Node = DAG.getBlockAddress(BlockAddress::get(HandlerBB), PtrVT);
+ DestBB.Ty = PtrTy;
+ TargetLowering::ArgListTy Args{SP, DestBB};
+
+ SDValue Callee = DAG.getExternalSymbol("_local_unwind", PtrVT);
+ TargetLowering::CallLoweringInfo CLI(DAG);
+ CLI.setDebugLoc(getCurSDLoc())
+ .setChain(getRoot())
+ .setCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()), Callee,
+ std::move(Args))
+ .setNoReturn();
+ CLI.CB = &I;
+ lowerInvokable(CLI, EHPadBB);
+ break;
+ }
}
} else if (I.countOperandBundlesOfType(LLVMContext::OB_deopt)) {
// Currently we do not lower any intrinsic calls with deopt operand bundles.
Index: llvm/lib/CodeGen/AsmPrinter/WinException.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -618,6 +618,17 @@
LastStartLabel = StateChange.NewStartLabel;
LastEHState = StateChange.NewState;
}
+ for (auto Entry : FuncInfo.SEHUnwindMap) {
+ if (!Entry.IsFinally && Entry.ToState != -1) {
+ // Mark up the destination of _local_unwind so it doesn't unwind
+ // too far.
+ //
+ // FIXME: Can this overlap with the EH_LABEL for an invoke?
+ auto *Handler = Entry.Handler.get<MachineBasicBlock *>();
+ const MCSymbol *Begin = Handler->getSymbol();
+ emitSEHActionsForRange(FuncInfo, Begin, Begin, Entry.ToState);
+ }
+ }
OS.emitLabel(TableEnd);
}
Index: llvm/include/llvm/IR/Intrinsics.td
===================================================================
--- llvm/include/llvm/IR/Intrinsics.td
+++ llvm/include/llvm/IR/Intrinsics.td
@@ -855,6 +855,9 @@
def int_seh_scope_begin : Intrinsic<[], [], [IntrNoMem]>;
def int_seh_scope_end : Intrinsic<[], [], [IntrNoMem]>;
+// Call _local_unwind to unwind to a local catchpad.
+def int_seh_localunwind : Intrinsic<[], [], [IntrNoReturn]>;
+
// Note: we treat stacksave/stackrestore as writemem because we don't otherwise
// model their dependencies on allocas.
def int_stacksave : DefaultAttrsIntrinsic<[llvm_ptr_ty]>,
Index: clang/test/CodeGen/windows-seh-return-finally.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/windows-seh-return-finally.c
@@ -0,0 +1,83 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --include-generated-funcs --version 2
+// RUN: %clang_cc1 -triple x86_64-windows -fcxx-exceptions -fexceptions -fms-extensions -S -emit-llvm %s -o - | FileCheck %s
+
+void f1(), f2(), f3();
+void f(int z) {
+ __try {
+ f1();
+ } __finally {
+ f2();
+ if (z)
+ return;
+ f3();
+ }
+}
+// CHECK-LABEL: define dso_local void @f
+// CHECK-SAME: (i32 noundef [[Z:%.*]]) #[[ATTR0:[0-9]+]] personality ptr @__C_specific_handler {
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT: [[RETNOW:%.*]] = alloca i8, align 1
+// CHECK-NEXT: call void (...) @llvm.localescape(ptr [[Z_ADDR]], ptr [[RETNOW]])
+// CHECK-NEXT: store i32 [[Z]], ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: store i8 0, ptr [[RETNOW]], align 1
+// CHECK-NEXT: invoke void @f1() #[[ATTR6:[0-9]+]]
+// CHECK-NEXT: to label [[INVOKE_CONT:%.*]] unwind label [[EHCLEANUP:%.*]]
+// CHECK: invoke.cont:
+// CHECK-NEXT: [[TMP0:%.*]] = call ptr @llvm.localaddress()
+// CHECK-NEXT: invoke void @"?fin$0@0@f@@"(i8 noundef 0, ptr noundef [[TMP0]])
+// CHECK-NEXT: to label [[INVOKE_CONT1:%.*]] unwind label [[CATCH_DISPATCH:%.*]]
+// CHECK: invoke.cont1:
+// CHECK-NEXT: br label [[__FINALLY_CONT:%.*]]
+// CHECK: __finally.cont:
+// CHECK-NEXT: [[TMP1:%.*]] = load i8, ptr [[RETNOW]], align 1
+// CHECK-NEXT: [[TMP2:%.*]] = icmp ne i8 [[TMP1]], 0
+// CHECK-NEXT: br i1 [[TMP2]], label [[IF_THEN4:%.*]], label [[IF_END5:%.*]]
+// CHECK: ehcleanup:
+// CHECK-NEXT: [[TMP3:%.*]] = cleanuppad within none []
+// CHECK-NEXT: [[TMP4:%.*]] = call ptr @llvm.localaddress()
+// CHECK-NEXT: invoke void @"?fin$0@0@f@@"(i8 noundef 1, ptr noundef [[TMP4]]) [ "funclet"(token [[TMP3]]) ]
+// CHECK-NEXT: to label [[INVOKE_CONT2:%.*]] unwind label [[CATCH_DISPATCH]]
+// CHECK: invoke.cont2:
+// CHECK-NEXT: [[TMP5:%.*]] = load i8, ptr [[RETNOW]], align 1
+// CHECK-NEXT: [[TMP6:%.*]] = icmp ne i8 [[TMP5]], 0
+// CHECK-NEXT: br i1 [[TMP6]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
+// CHECK: if.then:
+// CHECK-NEXT: invoke void @llvm.seh.localunwind()
+// CHECK-NEXT: to label [[INVOKE_CONT3:%.*]] unwind label [[CATCH_DISPATCH]]
+// CHECK: invoke.cont3:
+// CHECK-NEXT: unreachable
+// CHECK: if.end:
+// CHECK-NEXT: cleanupret from [[TMP3]] unwind label [[CATCH_DISPATCH]]
+// CHECK: catch.dispatch:
+// CHECK-NEXT: [[TMP7:%.*]] = catchswitch within none [label %__except.ret] unwind to caller
+// CHECK: __except.ret:
+// CHECK-NEXT: [[TMP8:%.*]] = catchpad within [[TMP7]] [ptr @__IsLocalUnwind]
+// CHECK-NEXT: catchret from [[TMP8]] to label [[IF_THEN4]]
+// CHECK: if.then4:
+// CHECK-NEXT: br label [[IF_END5]]
+// CHECK: if.end5:
+// CHECK-NEXT: ret void
+//
+//
+// CHECK-LABEL: define internal void @"?fin$0@0@f@@"
+// CHECK-SAME: (i8 noundef [[ABNORMAL_TERMINATION:%.*]], ptr noundef [[FRAME_POINTER:%.*]]) #[[ATTR1:[0-9]+]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[FRAME_POINTER_ADDR:%.*]] = alloca ptr, align 8
+// CHECK-NEXT: [[ABNORMAL_TERMINATION_ADDR:%.*]] = alloca i8, align 1
+// CHECK-NEXT: [[Z_ADDR:%.*]] = call ptr @llvm.localrecover(ptr @f, ptr [[FRAME_POINTER]], i32 0)
+// CHECK-NEXT: [[RETNOW:%.*]] = call ptr @llvm.localrecover(ptr @f, ptr [[FRAME_POINTER]], i32 1)
+// CHECK-NEXT: store ptr [[FRAME_POINTER]], ptr [[FRAME_POINTER_ADDR]], align 8
+// CHECK-NEXT: store i8 [[ABNORMAL_TERMINATION]], ptr [[ABNORMAL_TERMINATION_ADDR]], align 1
+// CHECK-NEXT: call void @f2()
+// CHECK-NEXT: [[TMP0:%.*]] = load i32, ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: [[TOBOOL:%.*]] = icmp ne i32 [[TMP0]], 0
+// CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
+// CHECK: if.then:
+// CHECK-NEXT: store i8 1, ptr [[RETNOW]], align 1
+// CHECK-NEXT: br label [[RETURN:%.*]]
+// CHECK: if.end:
+// CHECK-NEXT: call void @f3()
+// CHECK-NEXT: br label [[RETURN]]
+// CHECK: return:
+// CHECK-NEXT: ret void
+//
Index: clang/test/CodeGen/exceptions-seh-leave.c
===================================================================
--- clang/test/CodeGen/exceptions-seh-leave.c
+++ clang/test/CodeGen/exceptions-seh-leave.c
@@ -75,7 +75,7 @@
// CHECK-NOT: store i32 23
// CHECK: [[tryleave]]
// CHECK-NEXT: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
-// CHECK-NEXT: call void @"?fin$0@0@__leave_with___finally_simple@@"(i8 noundef 0, ptr noundef %[[fp]])
+// CHECK-NEXT: invoke void @"?fin$0@0@__leave_with___finally_simple@@"(i8 noundef 0, ptr noundef %[[fp]])
// __finally block doesn't return, __finally.cont doesn't exist.
int __leave_with___finally_noreturn(void) {
@@ -119,7 +119,7 @@
// CHECK-NOT: store i32 23
// CHECK: [[tryleave]]
// CHECK-NEXT: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
-// CHECK-NEXT: call void @"?fin$0@0@__leave_with___finally@@"(i8 noundef 0, ptr noundef %[[fp]])
+// CHECK-NEXT: invoke void @"?fin$0@0@__leave_with___finally@@"(i8 noundef 0, ptr noundef %[[fp]])
//////////////////////////////////////////////////////////////////////////////
@@ -152,10 +152,6 @@
// CHECK-NEXT: invoke void @"?fin$0@0@nested___except___finally@@"(i8 noundef 0, ptr noundef %[[fp]])
// CHECK-NEXT: to label %[[fin_cont:.*]] unwind label %[[g2_lpad:.*]]
-// CHECK: [[fin_cont]]
-// CHECK: store i32 51, ptr %
-// CHECK-NEXT: br label %[[trycont:[^ ]*]]
-
// CHECK: [[g1_lpad]]
// CHECK-NEXT: cleanuppad
// CHECK-NEXT: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
@@ -166,10 +162,6 @@
// CHECK: [[g2_lpad]]
// CHECK: catchpad {{.*}} [ptr null]
// CHECK: catchret
-// CHECK: br label %[[trycont]]
-
-// CHECK: [[trycont]]
-// CHECK-NEXT: ret i32 1
// CHECK-LABEL: define internal void @"?fin$0@0@nested___except___finally@@"(i8 noundef %abnormal_termination, ptr noundef %frame_pointer)
// CHECK: call void @g()
@@ -311,21 +303,18 @@
// CHECK: store i32 16, ptr %[[myres:[^ ]*]],
// CHECK: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
// CHECK-NEXT: invoke void @"?fin$1@0@nested___finally___finally@@"(i8 noundef 0, ptr noundef %[[fp]])
-// CHECK-NEXT: to label %[[finally_cont:.*]] unwind label %[[g2_lpad:.*]]
-
-// CHECK: [[finally_cont]]
-// CHECK: store i32 51, ptr %[[myres]]
-// CHECK: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
-// CHECK-NEXT: call void @"?fin$0@0@nested___finally___finally@@"(i8 noundef 0, ptr noundef %[[fp]])
-// CHECK-NEXT: ret i32 1
+// CHECK-NEXT: to label %[[finally_cont:.*]] unwind label %[[dispatch:.*]]
// CHECK: [[g1_lpad]]
// CHECK-NEXT: %[[padtoken:[^ ]*]] = cleanuppad within none []
// CHECK-NEXT: %[[fp:[^ ]*]] = call ptr @llvm.localaddress()
// CHECK-NEXT: invoke void @"?fin$1@0@nested___finally___finally@@"(i8 noundef 1, ptr noundef %[[fp]])
-// CHECK-NEXT: to label %[[finally_cont2:.*]] unwind label %[[g2_lpad]]
+// CHECK-NEXT: to label %[[finally_cont2:.*]] unwind label %[[dispatch]]
// CHECK: [[finally_cont2]]
-// CHECK: cleanupret from %[[padtoken]] unwind label %[[g2_lpad]]
+// CHECK: cleanupret from %[[padtoken]] unwind label %[[dispatch]]
+
+// CHECK: [[dispatch]]
+// CHECK: catchswitch {{.*}} unwind label %[[g2_lpad:.*]]
// CHECK: [[g2_lpad]]
// CHECK-NEXT: %[[padtoken:[^ ]*]] = cleanuppad within none []
Index: clang/test/CodeGen/exceptions-seh-finally.c
===================================================================
--- clang/test/CodeGen/exceptions-seh-finally.c
+++ clang/test/CodeGen/exceptions-seh-finally.c
@@ -181,7 +181,8 @@
//
// CHECK: [[outercont]]
// CHECK: call void @"?fin$0@0@nested___finally___finally@@"({{.*}})
-// CHECK-NEXT: ret i32 0
+// CHECK-NEXT: load i32
+// CHECK-NEXT: switch i32
//
// CHECK: [[lpad]]
// CHECK-NEXT: %[[pad:[^ ]*]] = cleanuppad
@@ -194,7 +195,8 @@
// CHECK-LABEL: define internal void @"?fin$1@0@nested___finally___finally@@"({{.*}})
// CHECK-SAME: [[finally_attrs]]
-// CHECK: unreachable
+// CHECK: store i32 1
+// CHECK-NEXT: ret void
// FIXME: Our behavior seems suspiciously different.
@@ -219,18 +221,23 @@
// CHECK-NEXT: to label %[[outercont:[^ ]*]] unwind label %[[lpad2:[^ ]*]]
//
// CHECK: [[outercont]]
-// CHECK: call void @"?fin$0@0@nested___finally___finally_with_eh_edge@@"({{.*}})
-// CHECK-NEXT: ret i32 912
+// CHECK-NEXT: br label
//
// CHECK: [[lpad1]]
// CHECK-NEXT: %[[innerpad:[^ ]*]] = cleanuppad
// CHECK: invoke void @"?fin$1@0@nested___finally___finally_with_eh_edge@@"({{.*}})
-// CHECK-NEXT: label %[[innercleanupretbb:[^ ]*]] unwind label %[[lpad2:[^ ]*]]
+// CHECK-NEXT: label %[[invokecont2:[^ ]*]] unwind label %[[lpad2:[^ ]*]]
//
-// CHECK: [[innercleanupretbb]]
+// CHECK: [[invokecont2]]
+// CHECK: br i1 {{.*}}, label %[[ifthen:[^ ]*]], label %[[ifend:[^ ]*]]
+//
+// CHECK: [[ifend]]
// CHECK-NEXT: cleanupret from %[[innerpad]] unwind label %[[lpad2]]
//
// CHECK: [[lpad2]]
+// CHECK: catchswitch {{.*}} unwind label %[[lpad3:[^ ]*]]
+//
+// CHECK: [[lpad3]]
// CHECK-NEXT: %[[outerpad:[^ ]*]] = cleanuppad
// CHECK: call void @"?fin$0@0@nested___finally___finally_with_eh_edge@@"({{.*}})
// CHECK-NEXT: cleanupret from %[[outerpad]] unwind to caller
@@ -241,7 +248,7 @@
// CHECK-LABEL: define internal void @"?fin$1@0@nested___finally___finally_with_eh_edge@@"({{.*}})
// CHECK-SAME: [[finally_attrs]]
-// CHECK: unreachable
+// CHECK: store i32 899
void finally_within_finally(void) {
__try {
Index: clang/lib/Sema/SemaStmt.cpp
===================================================================
--- clang/lib/Sema/SemaStmt.cpp
+++ clang/lib/Sema/SemaStmt.cpp
@@ -3895,8 +3895,6 @@
CurScope->updateNRVOCandidate(VD);
- CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
-
return R;
}
Index: clang/lib/CodeGen/CodeGenFunction.h
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.h
+++ clang/lib/CodeGen/CodeGenFunction.h
@@ -678,6 +678,16 @@
/// a value from the top of the stack.
SmallVector<Address, 1> SEHCodeSlotStack;
+ /// Variable that indicates abnormal termination from the a child finally
+ /// block.
+ SmallVector<Address, 1> SEHRetNowStack;
+
+ /// Ponter to the parent function's SEHRetNow variable.
+ Address SEHRetNowParent = Address::invalid();
+
+ /// Ponter to the root function's ReturnValue variable.
+ Address SEHReturnValue = Address::invalid();
+
/// Value returned by __exception_info intrinsic.
llvm::Value *SEHInfo = nullptr;
@@ -3286,11 +3296,14 @@
void EmitCXXTryStmt(const CXXTryStmt &S);
void EmitSEHTryStmt(const SEHTryStmt &S);
void EmitSEHLeaveStmt(const SEHLeaveStmt &S);
- void EnterSEHTryStmt(const SEHTryStmt &S);
- void ExitSEHTryStmt(const SEHTryStmt &S);
+ void EnterSEHTryStmt(const SEHTryStmt &S, bool &ContainsRetStmt);
+ void ExitSEHTryStmt(const SEHTryStmt &S, bool ContainsRetStmt);
void VolatilizeTryBlocks(llvm::BasicBlock *BB,
llvm::SmallPtrSet<llvm::BasicBlock *, 10> &V);
+ void EmitSEHLocalUnwind();
+ llvm::Function *GenerateSEHIsLocalUnwindFunction();
+
void pushSEHCleanup(CleanupKind kind,
llvm::Function *FinallyFunc);
void startOutlinedSEHHelper(CodeGenFunction &ParentCGF, bool IsFilter,
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -1298,10 +1298,10 @@
ReturnLocation);
}
- // Returning from an outlined SEH helper is UB, and we already warn on it.
+ Address ReturnValue = this->ReturnValue;
if (IsOutlinedSEHHelper) {
- Builder.CreateUnreachable();
- Builder.ClearInsertionPoint();
+ Builder.CreateStore(Builder.getInt8(1), SEHRetNowParent);
+ ReturnValue = SEHReturnValue;
}
// Emit the result value, even if unused, to evaluate the side effects.
Index: clang/lib/CodeGen/CGException.cpp
===================================================================
--- clang/lib/CodeGen/CGException.cpp
+++ clang/lib/CodeGen/CGException.cpp
@@ -1635,7 +1635,8 @@
}
void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
- EnterSEHTryStmt(S);
+ bool ContainsRetStmt = false;
+ EnterSEHTryStmt(S, ContainsRetStmt);
{
JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
@@ -1664,7 +1665,7 @@
else
delete TryExit.getBlock();
}
- ExitSEHTryStmt(S);
+ ExitSEHTryStmt(S, ContainsRetStmt);
}
// Recursively walk through blocks in a _try
@@ -1699,8 +1700,9 @@
namespace {
struct PerformSEHFinally final : EHScopeStack::Cleanup {
llvm::Function *OutlinedFinally;
- PerformSEHFinally(llvm::Function *OutlinedFinally)
- : OutlinedFinally(OutlinedFinally) {}
+ bool RetFromFinally;
+ PerformSEHFinally(llvm::Function *OutlinedFinally, bool RetFromFinally)
+ : OutlinedFinally(OutlinedFinally), RetFromFinally(RetFromFinally) {}
void Emit(CodeGenFunction &CGF, Flags F) override {
ASTContext &Context = CGF.getContext();
@@ -1744,6 +1746,21 @@
auto Callee = CGCallee::forDirect(OutlinedFinally);
CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
+
+ if (F.isForEHCleanup() && RetFromFinally) {
+ llvm::BasicBlock *AbnormalCont = CGF.createBasicBlock("if.then");
+ llvm::BasicBlock *NormalCont = CGF.createBasicBlock("if.end");
+ llvm::Value *ShouldRetLoad =
+ CGF.Builder.CreateLoad(CGF.SEHRetNowStack.back());
+ llvm::Value *ShouldRet = CGF.Builder.CreateIsNotNull(ShouldRetLoad);
+
+ CGF.Builder.CreateCondBr(ShouldRet, AbnormalCont, NormalCont);
+ CGF.EmitBlock(AbnormalCont);
+ CGF.EmitSEHLocalUnwind();
+ CGF.Builder.CreateUnreachable();
+
+ CGF.EmitBlock(NormalCont);
+ }
}
};
} // end anonymous namespace
@@ -1755,12 +1772,13 @@
const VarDecl *ParentThis;
llvm::SmallSetVector<const VarDecl *, 4> Captures;
Address SEHCodeSlot = Address::invalid();
+ bool ContainsRetStmt = false;
CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
: ParentCGF(ParentCGF), ParentThis(ParentThis) {}
// Return true if we need to do any capturing work.
bool foundCaptures() {
- return !Captures.empty() || SEHCodeSlot.isValid();
+ return !Captures.empty() || SEHCodeSlot.isValid() || ContainsRetStmt;
}
void Visit(const Stmt *S) {
@@ -1802,6 +1820,25 @@
break;
}
}
+
+ void VisitReturnStmt(const ReturnStmt *) { ContainsRetStmt = true; }
+};
+} // end anonymous namespace
+
+namespace {
+/// Find all local variable captures in the statement.
+struct ReturnStmtFinder : ConstStmtVisitor<ReturnStmtFinder> {
+ bool ContainsRetStmt = false;
+
+ void Visit(const Stmt *S) {
+ // See if this is a capture, then recurse.
+ ConstStmtVisitor::Visit(S);
+ for (const Stmt *Child : S->children())
+ if (Child)
+ Visit(Child);
+ }
+
+ void VisitReturnStmt(const ReturnStmt *) { ContainsRetStmt = true; }
};
} // end anonymous namespace
@@ -1850,7 +1887,8 @@
bool IsFilter) {
// Find all captures in the Stmt.
CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
- Finder.Visit(OutlinedStmt);
+ if (OutlinedStmt)
+ Finder.Visit(OutlinedStmt);
// We can exit early on x86_64 when there are no captures. We just have to
// save the exception code in filters so that __exception_code() works.
@@ -1988,6 +2026,16 @@
if (IsFilter)
EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
+
+ if (Finder.ContainsRetStmt) {
+ SEHRetNowParent = recoverAddrOfEscapedLocal(
+ ParentCGF, ParentCGF.SEHRetNowStack.back(), ParentFP);
+ Address ParentSEHRetVal =
+ ParentCGF.ParentCGF ? ParentCGF.SEHReturnValue : ParentCGF.ReturnValue;
+ if (ParentSEHRetVal.isValid())
+ SEHReturnValue =
+ recoverAddrOfEscapedLocal(ParentCGF, ParentSEHRetVal, ParentFP);
+ }
}
/// Arrange a function prototype that can be called by Windows exception
@@ -2147,19 +2195,93 @@
void CodeGenFunction::pushSEHCleanup(CleanupKind Kind,
llvm::Function *FinallyFunc) {
- EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
+ EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc, false);
}
-void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S) {
+void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S,
+ bool &ContainsRetStmt) {
CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
HelperCGF.ParentCGF = this;
if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
+ ReturnStmtFinder Finder;
+ Finder.Visit(Finally);
+ ContainsRetStmt = Finder.ContainsRetStmt;
+ if (ContainsRetStmt) {
+ // Suppose we have something like:
+ // __try {
+ // f1();
+ // } __finally {
+ // f2();
+ // if (z)
+ // return;
+ // f3();
+ // }
+ //
+ // We want to generate code something like this, where "StopUnwinding()"
+ // refers to the operation of aborting the unwind, and jumping back
+ // to normal code.
+ //
+ // int immediate_return = 0;
+ // __try {
+ // f1();
+ // } __finally {
+ // f2();
+ // if (z) {
+ // immediate_return = 1;
+ // goto end_of_finally;
+ // }
+ // f3();
+ // end_of_finally:
+ // if (_abnormal_termination())
+ // StopUnwinding();
+ // }
+ // if (immediate_return) {
+ // return;
+ // }
+ //
+ // To handle the non-unwind case, we need to synthesize the
+ // "immediate_return" variable, and use it to change control flow
+ // after the finally block.
+ //
+ // To make "StopUnwinding()" work, we use _local_unwind. This function
+ // tells the SEH unwinder to recompute the unwind action: instead of
+ // using the __except handler that was already computed, stop unwinding
+ // when the unwinder reaches the current function. (The mechanism used
+ // here is unofficially called a "collided unwind".)
+ //
+ // We represent the destination of _local_unwind with a fake CatchPad:
+ // when the backend sees a filter named "__IsLocalUnwind", it arranges
+ // the unwind tables so that _local_unwind stops at that CatchPad, but
+ // other unwinding ignores it.
+ //
+ // Note that this construct could itself be inside an __try or __finally
+ // block.
+ //
+ // If it's inside the __try of a __try/__finally, the outer __finally
+ // executes before the function returns.
+ //
+ // If it's inside a __finally, we need to jump out of that __finally
+ // in a similar way.
+
+ // Initialize the variable controlling the exception filter.
+ SEHRetNowStack.push_back(
+ CreateTempAlloca(CGM.Int8Ty, CharUnits::fromQuantity(1), "retnow"));
+ Builder.CreateStore(Builder.getInt8(0), SEHRetNowStack.back());
+
+ // Create the exception filter.
+ EHCatchScope *CatchScope = EHStack.pushCatch(1);
+ llvm::Function *FilterFunc = GenerateSEHIsLocalUnwindFunction();
+ llvm::Constant *OpaqueFunc =
+ llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
+ CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
+ }
// Outline the finally block.
llvm::Function *FinallyFunc =
HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
// Push a cleanup for __finally blocks.
- EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
+ EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc,
+ ContainsRetStmt);
return;
}
@@ -2191,10 +2313,72 @@
CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
}
-void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
+llvm::Function *CodeGenFunction::GenerateSEHIsLocalUnwindFunction() {
+ // IsLocalUnwind is a void dummy func just for readability.
+ if (llvm::Function *F = CGM.getModule().getFunction("__IsLocalUnwind"))
+ return F;
+
+ llvm::LLVMContext &Ctx = getLLVMContext();
+ llvm::Type *ArgTys[] = {llvm::Type::getInt8PtrTy(Ctx),
+ llvm::Type::getInt8PtrTy(Ctx)};
+ return llvm::Function::Create(
+ llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx), ArgTys, false),
+ llvm::GlobalVariable::ExternalWeakLinkage, "__IsLocalUnwind",
+ &CGM.getModule());
+}
+
+void CodeGenFunction::EmitSEHLocalUnwind() {
+ EmitRuntimeCallOrInvoke(CGM.getIntrinsic(llvm::Intrinsic::seh_localunwind));
+}
+
+void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S,
+ bool ContainsRetStmt) {
// Just pop the cleanup if it's a __finally block.
if (S.getFinallyHandler()) {
PopCleanupBlock();
+ if (ContainsRetStmt) {
+ // Create __except block and control flow handling for return from
+ // __finally. See comment in EnterSEHTryStmt.
+ //
+ // First, create the point where we check for a return
+ // from the __finally.
+ llvm::BasicBlock *ContBB = createBasicBlock("__finally.cont");
+ if (HaveInsertPoint())
+ Builder.CreateBr(ContBB);
+
+ EmitBlock(ContBB);
+
+ // On the normal path, check if we have a return-from-finally.
+ llvm::BasicBlock *AbnormalCont = createBasicBlock("if.then");
+ llvm::BasicBlock *NormalCont = createBasicBlock("if.end");
+ llvm::Value *ShouldRetLoad = Builder.CreateLoad(SEHRetNowStack.back());
+ llvm::Value *ShouldRet = Builder.CreateIsNotNull(ShouldRetLoad);
+
+ Builder.CreateCondBr(ShouldRet, AbnormalCont, NormalCont);
+
+ // Check if our filter function returned true.
+ EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
+ emitCatchDispatchBlock(*this, CatchScope);
+
+ // Grab the block before we pop the handler.
+ llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
+ EHStack.popCatch();
+
+ // The catch block only catches return-from-finally.
+ EmitBlockAfterUses(CatchPadBB);
+ llvm::CatchPadInst *CPI =
+ cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
+ Builder.CreateCatchRet(CPI, AbnormalCont);
+ EmitBlock(AbnormalCont);
+
+ // If the try block is nested inside a finally block, forward the
+ // return from __finally to the parent function.
+ if (SEHRetNowParent.isValid())
+ Builder.CreateStore(Builder.getInt8(1), SEHRetNowParent);
+ EmitBranchThroughCleanup(ReturnBlock);
+
+ EmitBlock(NormalCont);
+ }
return;
}
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