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[WinEH] Handle nested landing pads that return directly to the parent function.

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Differential Revision: http://reviews.llvm.org/D9684



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237063 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Kaylor 2015-05-11 23:06:02 +00:00
parent 96086ad501
commit e04fe6c135
6 changed files with 323 additions and 15 deletions
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114
lib/CodeGen/WinEHPrepare.cpp
View File

@ -98,6 +98,8 @@ private:
SetVector<BasicBlock *> &EHReturnBlocks);
void findCXXEHReturnPoints(Function &F,
SetVector<BasicBlock *> &EHReturnBlocks);
void getPossibleReturnTargets(Function *ParentF, Function *HandlerF,
SetVector<BasicBlock*> &Targets);
void completeNestedLandingPad(Function *ParentFn,
LandingPadInst *OutlinedLPad,
const LandingPadInst *OriginalLPad,
@ -700,6 +702,14 @@ bool WinEHPrepare::prepareExceptionHandlers(
F.getEntryBlock().getFirstInsertionPt());
}
// This container stores the llvm.eh.recover and IndirectBr instructions
// that make up the body of each landing pad after it has been outlined.
// We need to defer the population of the target list for the indirectbr
// until all landing pads have been outlined so that we can handle the
// case of blocks in the target that are reached only from nested
// landing pads.
SmallVector<std::pair<CallInst*, IndirectBrInst *>, 4> LPadImpls;
for (LandingPadInst *LPad : LPads) {
// Look for evidence that this landingpad has already been processed.
bool LPadHasActionList = false;
@ -819,18 +829,28 @@ bool WinEHPrepare::prepareExceptionHandlers(
CallInst *Recover =
CallInst::Create(ActionIntrin, ActionArgs, "recover", LPadBB);
// Add an indirect branch listing possible successors of the catch handlers.
SetVector<BasicBlock *> ReturnTargets;
for (ActionHandler *Action : Actions) {
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
const auto &CatchTargets = CatchAction->getReturnTargets();
ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end());
if (isAsynchronousEHPersonality(Personality)) {
// SEH can create the target list directly, since catch handlers
// are not outlined.
SetVector<BasicBlock *> ReturnTargets;
for (ActionHandler *Action : Actions) {
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
const auto &CatchTargets = CatchAction->getReturnTargets();
ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end());
}
}
IndirectBrInst *Branch =
IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB);
for (BasicBlock *Target : ReturnTargets)
Branch->addDestination(Target);
} else {
// C++ EH must defer populating the targets to handle the case of
// targets that are reached indirectly through nested landing pads.
IndirectBrInst *Branch =
IndirectBrInst::Create(Recover, 0, LPadBB);
LPadImpls.push_back(std::make_pair(Recover, Branch));
}
IndirectBrInst *Branch =
IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB);
for (BasicBlock *Target : ReturnTargets)
Branch->addDestination(Target);
} // End for each landingpad
// If nothing got outlined, there is no more processing to be done.
@ -844,6 +864,44 @@ bool WinEHPrepare::prepareExceptionHandlers(
completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo);
NestedLPtoOriginalLP.clear();
// Populate the indirectbr instructions' target lists if we deferred
// doing so above.
SetVector<BasicBlock*> CheckedTargets;
for (auto &LPadImplPair : LPadImpls) {
IntrinsicInst *Recover = cast<IntrinsicInst>(LPadImplPair.first);
IndirectBrInst *Branch = LPadImplPair.second;
// Get a list of handlers called by
SmallVector<ActionHandler *, 4> ActionList;
parseEHActions(Recover, ActionList);
// Add an indirect branch listing possible successors of the catch handlers.
SetVector<BasicBlock *> ReturnTargets;
for (ActionHandler *Action : ActionList) {
if (auto *CA = dyn_cast<CatchHandler>(Action)) {
Function *Handler = cast<Function>(CA->getHandlerBlockOrFunc());
getPossibleReturnTargets(&F, Handler, ReturnTargets);
}
}
for (BasicBlock *Target : ReturnTargets) {
Branch->addDestination(Target);
// The target may be a block that we excepted to get pruned.
// If it is, it may contain a call to llvm.eh.endcatch.
if (CheckedTargets.insert(Target)) {
// Earlier preparations guarantee that all calls to llvm.eh.endcatch
// will be followed by an unconditional branch.
auto *Br = dyn_cast<BranchInst>(Target->getTerminator());
if (Br && Br->isUnconditional() &&
Br != Target->getFirstNonPHIOrDbgOrLifetime()) {
Instruction *Prev = Br->getPrevNode();
if (match(cast<Value>(Prev), m_Intrinsic<Intrinsic::eh_endcatch>()))
Prev->eraseFromParent();
}
}
}
}
LPadImpls.clear();
F.addFnAttr("wineh-parent", F.getName());
// Delete any blocks that were only used by handlers that were outlined above.
@ -976,6 +1034,42 @@ void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) {
RecursivelyDeleteTriviallyDeadInstructions(U);
}
void WinEHPrepare::getPossibleReturnTargets(Function *ParentF,
Function *HandlerF,
SetVector<BasicBlock*> &Targets) {
for (BasicBlock &BB : *HandlerF) {
// If the handler contains landing pads, check for any
// handlers that may return directly to a block in the
// parent function.
if (auto *LPI = BB.getLandingPadInst()) {
IntrinsicInst *Recover = cast<IntrinsicInst>(LPI->getNextNode());
SmallVector<ActionHandler *, 4> ActionList;
parseEHActions(Recover, ActionList);
for (auto *Action : ActionList) {
if (auto *CH = dyn_cast<CatchHandler>(Action)) {
Function *NestedF = cast<Function>(CH->getHandlerBlockOrFunc());
getPossibleReturnTargets(ParentF, NestedF, Targets);
}
}
}
auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator());
if (!Ret)
continue;
// Handler functions must always return a block address.
BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
// If this is the handler for a nested landing pad, the
// return address may have been remapped to a block in the
// parent handler. We're not interested in those.
if (BA->getFunction() != ParentF)
continue;
Targets.insert(BA->getBasicBlock());
}
}
void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
LandingPadInst *OutlinedLPad,
const LandingPadInst *OriginalLPad,

2
test/CodeGen/WinEH/cppeh-catch-unwind.ll
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@ -98,7 +98,7 @@ lpad1: ; preds = %invoke.cont
; CHECK-NEXT: cleanup
; CHECK-NEXT: catch i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*)
; CHECK-NEXT: [[RECOVER3:\%.+]] = call i8* (...) @llvm.eh.actions(i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 2, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch1", i32 0, void (i8*, i8*)* @"\01?test@@YAXXZ.cleanup")
; CHECK-NEXT: indirectbr i8* [[RECOVER3]], [label %try.cont]
; CHECK-NEXT: indirectbr i8* [[RECOVER3]], [label %try.cont, label %try.cont15]
lpad3: ; preds = %invoke.cont2
%8 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)

2
test/CodeGen/WinEH/cppeh-nested-1.ll
View File

@ -56,7 +56,7 @@ invoke.cont: ; preds = %entry
; CHECK: catch i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*)
; CHECK: catch i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0M@8" to i8*)
; CHECK: [[RECOVER:\%.+]] = call i8* (...) @llvm.eh.actions(i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 0, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch", i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0M@8" to i8*), i32 1, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch1")
; CHECK: indirectbr i8* [[RECOVER]], [label %try.cont, label %try.cont10]
; CHECK: indirectbr i8* [[RECOVER]], [label %try.cont10, label %try.cont]
lpad: ; preds = %entry
%0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)

4
test/CodeGen/WinEH/cppeh-nested-2.ll
View File

@ -114,7 +114,7 @@ lpad: ; preds = %try.cont, %entry
; CHECK-SAME: i32 1, i8* bitcast (i8** @_ZTIi to i8*), i32 1, i8* (i8*, i8*)* @_Z4testv.catch1,
; CHECK-SAME: i32 0, void (i8*, i8*)* @_Z4testv.cleanup,
; CHECK-SAME: i32 1, i8* bitcast (i8** @_ZTIf to i8*), i32 0, i8* (i8*, i8*)* @_Z4testv.catch)
; CHECK-NEXT: indirectbr i8* [[RECOVER1]], [label %try.cont, label %try.cont19]
; CHECK-NEXT: indirectbr i8* [[RECOVER1]], [label %try.cont19, label %try.cont]
lpad1: ; preds = %invoke.cont4, %invoke.cont
%tmp3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
@ -137,7 +137,7 @@ lpad1: ; preds = %invoke.cont4, %invo
; CHECK-SAME: i32 1, i8* bitcast (i8** @_ZTIi to i8*), i32 1, i8* (i8*, i8*)* @_Z4testv.catch1,
; CHECK-SAME: i32 0, void (i8*, i8*)* @_Z4testv.cleanup,
; CHECK-SAME: i32 1, i8* bitcast (i8** @_ZTIf to i8*), i32 0, i8* (i8*, i8*)* @_Z4testv.catch)
; CHECK-NEXT: indirectbr i8* [[RECOVER3]], [label %try.cont, label %try.cont19]
; CHECK-NEXT: indirectbr i8* [[RECOVER3]], [label %try.cont19, label %try.cont]
lpad3: ; preds = %invoke.cont2
%tmp6 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)

2
test/CodeGen/WinEH/cppeh-nested-3.ll
View File

@ -64,7 +64,7 @@ invoke.cont: ; preds = %entry
; CHECK: catch i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*)
; CHECK: catch i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0M@8" to i8*)
; CHECK: [[RECOVER:\%.+]] = call i8* (...) @llvm.eh.actions(i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 0, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch", i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0M@8" to i8*), i32 1, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch1")
; CHECK: indirectbr i8* [[RECOVER]], [label %try.cont10, label %try.cont19]
; CHECK: indirectbr i8* [[RECOVER]], [label %try.cont19, label %try.cont10]
lpad: ; preds = %entry
%0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)

214
test/CodeGen/WinEH/cppeh-nested-rethrow.ll Normal file
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@ -0,0 +1,214 @@
; RUN: opt -mtriple=x86_64-pc-windows-msvc -winehprepare -S -o - < %s | FileCheck %s
; This test was generated from the following code.
;
; void test1() {
; try {
; try {
; throw 1;
; } catch(...) { throw; }
; } catch (...) { }
; }
; void test2() {
; try {
; throw 1;
; } catch(...) {
; try {
; throw;
; } catch (...) {}
; }
; }
;
; These two functions result in functionally equivalent code, but the last
; catch block contains a call to llvm.eh.endcatch that tripped up processing
; during development.
;
; The main purpose of this test is to verify that we can correctly
; handle the case of nested landing pads that return directly to a block in
; the parent function.
; ModuleID = 'cppeh-nested-rethrow.cpp'
target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"
%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
%eh.CatchableType = type { i32, i32, i32, i32, i32, i32, i32 }
%eh.CatchableTypeArray.1 = type { i32, [1 x i32] }
%eh.ThrowInfo = type { i32, i32, i32, i32 }
$"\01??_R0H@8" = comdat any
$"_CT??_R0H@84" = comdat any
$_CTA1H = comdat any
$_TI1H = comdat any
@"\01??_7type_info@@6B@" = external constant i8*
@"\01??_R0H@8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
@__ImageBase = external constant i8
@"_CT??_R0H@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32), i32 0, i32 -1, i32 0, i32 4, i32 0 }, section ".xdata", comdat
@_CTA1H = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x i32] [i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%eh.CatchableType* @"_CT??_R0H@84" to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32)] }, section ".xdata", comdat
@_TI1H = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i32 0, i32 0, i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%eh.CatchableTypeArray.1* @_CTA1H to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32) }, section ".xdata", comdat
; CHECK-LABEL: define void @"\01?test1@@YAXXZ"()
; CHECK: entry:
; CHECK: call void (...) @llvm.frameescape
; Function Attrs: nounwind uwtable
define void @"\01?test1@@YAXXZ"() #0 {
entry:
%tmp = alloca i32, align 4
%exn.slot = alloca i8*
%ehselector.slot = alloca i32
store i32 1, i32* %tmp
%0 = bitcast i32* %tmp to i8*
invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* @_TI1H) #2
to label %unreachable unwind label %lpad
lpad: ; preds = %entry
%1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
catch i8* null
%2 = extractvalue { i8*, i32 } %1, 0
store i8* %2, i8** %exn.slot
%3 = extractvalue { i8*, i32 } %1, 1
store i32 %3, i32* %ehselector.slot
br label %catch
catch: ; preds = %lpad
%exn = load i8*, i8** %exn.slot
call void @llvm.eh.begincatch(i8* %exn, i8* null) #1
invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #2
to label %unreachable unwind label %lpad1
lpad1: ; preds = %catch
%4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
catch i8* null
%5 = extractvalue { i8*, i32 } %4, 0
store i8* %5, i8** %exn.slot
%6 = extractvalue { i8*, i32 } %4, 1
store i32 %6, i32* %ehselector.slot
br label %catch2
catch2: ; preds = %lpad1
%exn3 = load i8*, i8** %exn.slot
call void @llvm.eh.begincatch(i8* %exn3, i8* null) #1
call void @llvm.eh.endcatch() #1
br label %try.cont4
; This block should not be eliminated.
; CHECK: try.cont4:
try.cont4: ; preds = %catch2, %try.cont
ret void
try.cont: ; No predecessors!
br label %try.cont4
unreachable: ; preds = %catch, %entry
unreachable
; CHECK: }
}
declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
declare i32 @__CxxFrameHandler3(...)
; Function Attrs: nounwind
declare void @llvm.eh.begincatch(i8* nocapture, i8* nocapture) #1
; Function Attrs: nounwind
declare void @llvm.eh.endcatch() #1
; CHECK-LABEL: define void @"\01?test2@@YAXXZ"()
; CHECK: entry:
; CHECK: call void (...) @llvm.frameescape
; Function Attrs: nounwind uwtable
define void @"\01?test2@@YAXXZ"() #0 {
entry:
%tmp = alloca i32, align 4
%exn.slot = alloca i8*
%ehselector.slot = alloca i32
store i32 1, i32* %tmp
%0 = bitcast i32* %tmp to i8*
invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* @_TI1H) #2
to label %unreachable unwind label %lpad
lpad: ; preds = %entry
%1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
catch i8* null
%2 = extractvalue { i8*, i32 } %1, 0
store i8* %2, i8** %exn.slot
%3 = extractvalue { i8*, i32 } %1, 1
store i32 %3, i32* %ehselector.slot
br label %catch
catch: ; preds = %lpad
%exn = load i8*, i8** %exn.slot
call void @llvm.eh.begincatch(i8* %exn, i8* null) #1
invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #2
to label %unreachable unwind label %lpad1
lpad1: ; preds = %catch
%4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
catch i8* null
%5 = extractvalue { i8*, i32 } %4, 0
store i8* %5, i8** %exn.slot
%6 = extractvalue { i8*, i32 } %4, 1
store i32 %6, i32* %ehselector.slot
br label %catch2
catch2: ; preds = %lpad1
%exn3 = load i8*, i8** %exn.slot
call void @llvm.eh.begincatch(i8* %exn3, i8* null) #1
call void @llvm.eh.endcatch() #1
br label %try.cont
; This block should not be eliminated.
; CHECK: try.cont:
; The endcatch call should be eliminated.
; CHECK-NOT: call void @llvm.eh.endcatch()
try.cont: ; preds = %catch2
call void @llvm.eh.endcatch() #1
br label %try.cont4
try.cont4: ; preds = %try.cont
ret void
unreachable: ; preds = %catch, %entry
unreachable
; CHECK: }
}
; The outlined test1.catch handler should not contain a return instruction.
; CHECK-LABEL: define internal i8* @"\01?test1@@YAXXZ.catch"(i8*, i8*)
; CHECK-NOT: ret
; CHECK: }
; The outlined test1.catch1 handler should return to a valid block address.
; CHECK-LABEL: define internal i8* @"\01?test1@@YAXXZ.catch1"(i8*, i8*)
; WILL-CHECK: ret i8* inttoptr (
; CHECK-NOT: ret i8* inttoptr (i32 1 to i8*)
; CHECK: }
; The outlined test2.catch handler should not contain a return instruction.
; CHECK-LABEL: define internal i8* @"\01?test2@@YAXXZ.catch"(i8*, i8*)
; CHECK-NOT: ret
; CHECK: }
; The outlined test2.catch1 handler should return to a valid block address.
; CHECK-LABEL: define internal i8* @"\01?test2@@YAXXZ.catch2"(i8*, i8*)
; WILL-CHECK: ret i8* inttoptr (
; CHECK-NOT: ret i8* inttoptr (i32 1 to i8*)
; CHECK: }
attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind }
attributes #2 = { noreturn }
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"PIC Level", i32 2}
!1 = !{!"clang version 3.7.0 (trunk 236059)"}