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[WebAssembly] Fix call unwind mismatches 

This adds `delegate` instruction and use it to fix unwind destination
mismatches created by marker placement in CFGStackify.

There are two kinds of unwind destination mismatches:
- Mismatches caused by throwing instructions (here we call it "call
  unwind mismatches", even though `throw` and `rethrow` can also cause
  mismatches)
- Mismatches caused by `catch`es, in case a foreign exception is not
  caught by the nearest `catch` and the next outer `catch` is not the
  catch it should unwind to. This kind of mismatches didn't exist in the
  previous version of the spec, because in the previous spec `catch` was
  effectively `catch_all`, catching all exceptions.

This implements routines to fix the first kind of unwind mismatches,
which we call "call unwind mismatches". The second mismatch (catch
unwind mismatches) will be fixed in a later CL.

This also reenables all previously disabled tests in cfg-stackify-eh.ll
and updates FileCheck lines to match the new spec. Two tests were
deleted because they specifically tested the way we fixed unwind
mismatches before using `exnref`s and branches, which we don't do
anymore.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94048
This commit is contained in:
Heejin Ahn 2020-12-28 05:10:22 -08:00
parent 79a6cfc29e
commit ed41945faa
5 changed files with 674 additions and 254 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp
View File

@ -93,36 +93,41 @@ void WebAssemblyInstPrinter::printInst(const MCInst *MI, uint64_t Address,
case WebAssembly::LOOP:
case WebAssembly::LOOP_S:
printAnnotation(OS, "label" + utostr(ControlFlowCounter) + ':');
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, true));
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, true));
DelegateStack.push_back(ControlFlowCounter++);
return;
case WebAssembly::BLOCK:
case WebAssembly::BLOCK_S:
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, false));
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false));
DelegateStack.push_back(ControlFlowCounter++);
return;
case WebAssembly::TRY:
case WebAssembly::TRY_S:
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false));
EHPadStack.push_back(ControlFlowCounter++);
EHPadStack.push_back(ControlFlowCounter);
DelegateStack.push_back(ControlFlowCounter++);
return;
case WebAssembly::END_LOOP:
case WebAssembly::END_LOOP_S:
if (ControlFlowStack.empty()) {
if (ControlFlowStack.empty() || DelegateStack.empty()) {
printAnnotation(OS, "End marker mismatch!");
} else {
ControlFlowStack.pop_back();
DelegateStack.pop_back();
}
return;
case WebAssembly::END_BLOCK:
case WebAssembly::END_BLOCK_S:
if (ControlFlowStack.empty()) {
if (ControlFlowStack.empty() || DelegateStack.empty()) {
printAnnotation(OS, "End marker mismatch!");
} else {
printAnnotation(
OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':');
DelegateStack.pop_back();
}
return;
@ -140,10 +145,11 @@ void WebAssemblyInstPrinter::printInst(const MCInst *MI, uint64_t Address,
case WebAssembly::CATCH_S:
case WebAssembly::CATCH_ALL:
case WebAssembly::CATCH_ALL_S:
if (EHPadStack.empty()) {
if (EHPadStack.empty() || DelegateStack.empty()) {
printAnnotation(OS, "try-catch mismatch!");
} else {
printAnnotation(OS, "catch" + utostr(EHPadStack.pop_back_val()) + ':');
DelegateStack.pop_back();
}
return;
@ -157,6 +163,33 @@ void WebAssemblyInstPrinter::printInst(const MCInst *MI, uint64_t Address,
printAnnotation(OS, "down to catch" + utostr(EHPadStack.back()));
}
return;
case WebAssembly::DELEGATE:
case WebAssembly::DELEGATE_S:
if (ControlFlowStack.empty() || EHPadStack.empty() ||
DelegateStack.empty()) {
printAnnotation(OS, "try-delegate mismatch!");
} else {
// 'delegate' is
// 1. A marker for the end of block label
// 2. A destination for throwing instructions
// 3. An instruction that itself rethrows to another 'catch'
assert(ControlFlowStack.back().first == EHPadStack.back() &&
EHPadStack.back() == DelegateStack.back());
std::string Label = "label/catch" +
utostr(ControlFlowStack.pop_back_val().first) +
": ";
EHPadStack.pop_back();
DelegateStack.pop_back();
uint64_t Depth = MI->getOperand(0).getImm();
if (Depth >= DelegateStack.size()) {
Label += "to caller";
} else {
Label += "down to catch" + utostr(DelegateStack.rbegin()[Depth]);
}
printAnnotation(OS, Label);
}
return;
}
// Annotate any control flow label references.

5
llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.h
View File

@ -27,6 +27,11 @@ class WebAssemblyInstPrinter final : public MCInstPrinter {
uint64_t ControlFlowCounter = 0;
SmallVector<std::pair<uint64_t, bool>, 4> ControlFlowStack;
SmallVector<uint64_t, 4> EHPadStack;
// 'delegate' can target any block-like structure, but in case the target is
// 'try', it rethrows to the corresponding 'catch'. Because it can target all
// blocks but with a slightly different semantics with branches, we need a
// separate stack for 'delegate'.
SmallVector<uint64_t, 4> DelegateStack;
public:
WebAssemblyInstPrinter(const MCAsmInfo &MAI, const MCInstrInfo &MII,

502
llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
View File

@ -38,7 +38,7 @@ using WebAssembly::SortRegionInfo;
#define DEBUG_TYPE "wasm-cfg-stackify"
STATISTIC(NumUnwindMismatches, "Number of EH pad unwind mismatches found");
STATISTIC(NumCallUnwindMismatches, "Number of call unwind mismatches found");
namespace {
class WebAssemblyCFGStackify final : public MachineFunctionPass {
@ -68,24 +68,35 @@ class WebAssemblyCFGStackify final : public MachineFunctionPass {
void placeBlockMarker(MachineBasicBlock &MBB);
void placeLoopMarker(MachineBasicBlock &MBB);
void placeTryMarker(MachineBasicBlock &MBB);
// Exception handling related functions
bool fixCallUnwindMismatches(MachineFunction &MF);
bool fixCatchUnwindMismatches(MachineFunction &MF);
void addTryDelegate(MachineInstr *RangeBegin, MachineInstr *RangeEnd,
MachineBasicBlock *DelegateDest);
void recalculateScopeTops(MachineFunction &MF);
void removeUnnecessaryInstrs(MachineFunction &MF);
bool fixUnwindMismatches(MachineFunction &MF);
// Wrap-up
unsigned getDepth(const SmallVectorImpl<const MachineBasicBlock *> &Stack,
const MachineBasicBlock *MBB);
void rewriteDepthImmediates(MachineFunction &MF);
void fixEndsAtEndOfFunction(MachineFunction &MF);
void cleanupFunctionData(MachineFunction &MF);
// For each BLOCK|LOOP|TRY, the corresponding END_(BLOCK|LOOP|TRY).
// For each BLOCK|LOOP|TRY, the corresponding END_(BLOCK|LOOP|TRY) or DELEGATE
// (in case of TRY).
DenseMap<const MachineInstr *, MachineInstr *> BeginToEnd;
// For each END_(BLOCK|LOOP|TRY), the corresponding BLOCK|LOOP|TRY.
// For each END_(BLOCK|LOOP|TRY) or DELEGATE, the corresponding
// BLOCK|LOOP|TRY.
DenseMap<const MachineInstr *, MachineInstr *> EndToBegin;
// <TRY marker, EH pad> map
DenseMap<const MachineInstr *, MachineBasicBlock *> TryToEHPad;
// <EH pad, TRY marker> map
DenseMap<const MachineBasicBlock *, MachineInstr *> EHPadToTry;
// There can be an appendix block at the end of each function, shared for:
// - creating a correct signature for fallthrough returns
// - target for rethrows that need to unwind to the caller, but are trapped
// inside another try/catch
// We need an appendix block to place 'end_loop' or 'end_try' marker when the
// loop / exception bottom block is the last block in a function
MachineBasicBlock *AppendixBB = nullptr;
MachineBasicBlock *getAppendixBlock(MachineFunction &MF) {
if (!AppendixBB) {
@ -97,6 +108,19 @@ class WebAssemblyCFGStackify final : public MachineFunctionPass {
return AppendixBB;
}
// Before running rewriteDepthImmediates function, 'delegate' has a BB as its
// destination operand. getFakeCallerBlock() returns a fake BB that will be
// used for the operand when 'delegate' needs to rethrow to the caller. This
// will be rewritten as an immediate value that is the number of block depths
// + 1 in rewriteDepthImmediates, and this fake BB will be removed at the end
// of the pass.
MachineBasicBlock *FakeCallerBB = nullptr;
MachineBasicBlock *getFakeCallerBlock(MachineFunction &MF) {
if (!FakeCallerBB)
FakeCallerBB = MF.CreateMachineBasicBlock();
return FakeCallerBB;
}
// Helper functions to register / unregister scope information created by
// marker instructions.
void registerScope(MachineInstr *Begin, MachineInstr *End);
@ -189,6 +213,7 @@ void WebAssemblyCFGStackify::registerScope(MachineInstr *Begin,
EndToBegin[End] = Begin;
}
// When 'End' is not an 'end_try' but 'delegate, EHPad is nullptr.
void WebAssemblyCFGStackify::registerTryScope(MachineInstr *Begin,
MachineInstr *End,
MachineBasicBlock *EHPad) {
@ -675,6 +700,8 @@ void WebAssemblyCFGStackify::removeUnnecessaryInstrs(MachineFunction &MF) {
while (Cont->isEHPad()) {
MachineInstr *Try = EHPadToTry[Cont];
MachineInstr *EndTry = BeginToEnd[Try];
// We started from an EH pad, so the end marker cannot be a delegate
assert(EndTry->getOpcode() != WebAssembly::DELEGATE);
Cont = EndTry->getParent();
}
@ -719,8 +746,10 @@ void WebAssemblyCFGStackify::removeUnnecessaryInstrs(MachineFunction &MF) {
for (auto &MI : MBB) {
if (MI.getOpcode() != WebAssembly::TRY)
continue;
MachineInstr *Try = &MI, *EndTry = BeginToEnd[Try];
if (EndTry->getOpcode() == WebAssembly::DELEGATE)
continue;
MachineBasicBlock *TryBB = Try->getParent();
MachineBasicBlock *Cont = EndTry->getParent();
int64_t RetType = Try->getOperand(0).getImm();
@ -763,12 +792,8 @@ static unsigned getCopyOpcode(const TargetRegisterClass *RC) {
// When MBB is split into MBB and Split, we should unstackify defs in MBB that
// have their uses in Split.
// FIXME This function will be used when fixing unwind mismatches, but the old
// version of that function was removed for the moment and the new version has
// not yet been added. So 'LLVM_ATTRIBUTE_UNUSED' is added to suppress the
// warning. Remove the attribute after the new functionality is added.
LLVM_ATTRIBUTE_UNUSED static void
unstackifyVRegsUsedInSplitBB(MachineBasicBlock &MBB, MachineBasicBlock &Split) {
static void unstackifyVRegsUsedInSplitBB(MachineBasicBlock &MBB,
MachineBasicBlock &Split) {
MachineFunction &MF = *MBB.getParent();
const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
auto &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
@ -826,14 +851,409 @@ unstackifyVRegsUsedInSplitBB(MachineBasicBlock &MBB, MachineBasicBlock &Split) {
}
}
bool WebAssemblyCFGStackify::fixUnwindMismatches(MachineFunction &MF) {
// TODO Implement this
// Wrap the given range of instruction with try-delegate. RangeBegin and
// RangeEnd are inclusive.
void WebAssemblyCFGStackify::addTryDelegate(MachineInstr *RangeBegin,
MachineInstr *RangeEnd,
MachineBasicBlock *DelegateDest) {
auto *BeginBB = RangeBegin->getParent();
auto *EndBB = RangeEnd->getParent();
MachineFunction &MF = *BeginBB->getParent();
const auto &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
// Local expression tree before the first call of this range should go
// after the nested TRY.
SmallPtrSet<const MachineInstr *, 4> AfterSet;
AfterSet.insert(RangeBegin);
for (auto I = MachineBasicBlock::iterator(RangeBegin), E = BeginBB->begin();
I != E; --I) {
if (std::prev(I)->isDebugInstr() || std::prev(I)->isPosition())
continue;
if (WebAssembly::isChild(*std::prev(I), MFI))
AfterSet.insert(&*std::prev(I));
else
break;
}
// Create the nested try instruction.
auto TryPos = getLatestInsertPos(
BeginBB, SmallPtrSet<const MachineInstr *, 4>(), AfterSet);
MachineInstr *Try = BuildMI(*BeginBB, TryPos, RangeBegin->getDebugLoc(),
TII.get(WebAssembly::TRY))
.addImm(int64_t(WebAssembly::BlockType::Void));
// Create a BB to insert the 'delegate' instruction.
MachineBasicBlock *DelegateBB = MF.CreateMachineBasicBlock();
// If the destination of 'delegate' is not the caller, adds the destination to
// the BB's successors.
if (DelegateDest != FakeCallerBB)
DelegateBB->addSuccessor(DelegateDest);
auto SplitPos = std::next(RangeEnd->getIterator());
if (SplitPos == EndBB->end()) {
// If the range's end instruction is at the end of the BB, insert the new
// delegate BB after the current BB.
MF.insert(std::next(EndBB->getIterator()), DelegateBB);
EndBB->addSuccessor(DelegateBB);
} else {
// If the range's end instruction is in the middle of the BB, we split the
// BB into two and insert the delegate BB in between.
// - Before:
// bb:
// range_end
// other_insts
//
// - After:
// pre_bb: (previous 'bb')
// range_end
// delegate_bb: (new)
// delegate
// post_bb: (new)
// other_insts
MachineBasicBlock *PreBB = EndBB;
MachineBasicBlock *PostBB = MF.CreateMachineBasicBlock();
MF.insert(std::next(PreBB->getIterator()), PostBB);
MF.insert(std::next(PreBB->getIterator()), DelegateBB);
PostBB->splice(PostBB->end(), PreBB, SplitPos, PreBB->end());
PostBB->transferSuccessors(PreBB);
unstackifyVRegsUsedInSplitBB(*PreBB, *PostBB);
PreBB->addSuccessor(DelegateBB);
PreBB->addSuccessor(PostBB);
}
// Add 'delegate' instruction in the delegate BB created above.
MachineInstr *Delegate = BuildMI(DelegateBB, RangeEnd->getDebugLoc(),
TII.get(WebAssembly::DELEGATE))
.addMBB(DelegateDest);
registerTryScope(Try, Delegate, nullptr);
}
bool WebAssemblyCFGStackify::fixCallUnwindMismatches(MachineFunction &MF) {
// Linearizing the control flow by placing TRY / END_TRY markers can create
// mismatches in unwind destinations for throwing instructions, such as calls.
//
// We use the 'delegate' instruction to fix the unwind mismatches. 'delegate'
// instruction delegates an exception to an outer 'catch'. It can target not
// only 'catch' but all block-like structures including another 'delegate',
// but with slightly different semantics than branches. When it targets a
// 'catch', it will delegate the exception to that catch. It is being
// discussed how to define the semantics when 'delegate''s target is a non-try
// block: it will either be a validation failure or it will target the next
// outer try-catch. But anyway our LLVM backend currently does not generate
// such code. The example below illustrates where the 'delegate' instruction
// in the middle will delegate the exception to, depending on the value of N.
// try
// try
// block
// try
// try
// call @foo
// delegate N ;; Where will this delegate to?
// catch ;; N == 0
// end
// end ;; N == 1 (invalid; will not be generated)
// delegate ;; N == 2
// catch ;; N == 3
// end
// ;; N == 4 (to caller)
// 1. When an instruction may throw, but the EH pad it will unwind to can be
// different from the original CFG.
//
// Example: we have the following CFG:
// bb0:
// call @foo ; if it throws, unwind to bb2
// bb1:
// call @bar ; if it throws, unwind to bb3
// bb2 (ehpad):
// catch
// ...
// bb3 (ehpad)
// catch
// ...
//
// And the CFG is sorted in this order. Then after placing TRY markers, it
// will look like: (BB markers are omitted)
// try
// try
// call @foo
// call @bar ;; if it throws, unwind to bb3
// catch ;; ehpad (bb2)
// ...
// end_try
// catch ;; ehpad (bb3)
// ...
// end_try
//
// Now if bar() throws, it is going to end up ip in bb2, not bb3, where it
// is supposed to end up. We solve this problem by wrapping the mismatching
// call with an inner try-delegate that rethrows the exception to the right
// 'catch'.
//
//
// try
// try
// call @foo
// try ;; (new)
// call @bar
// delegate 1 (bb3) ;; (new)
// catch ;; ehpad (bb2)
// ...
// end_try
// catch ;; ehpad (bb3)
// ...
// end_try
//
// ---
// 2. The same as 1, but in this case an instruction unwinds to a caller
// function and not another EH pad.
//
// Example: we have the following CFG:
// bb0:
// call @foo ; if it throws, unwind to bb2
// bb1:
// call @bar ; if it throws, unwind to caller
// bb2 (ehpad):
// catch
// ...
//
// And the CFG is sorted in this order. Then after placing TRY markers, it
// will look like:
// try
// call @foo
// call @bar ;; if it throws, unwind to caller
// catch ;; ehpad (bb2)
// ...
// end_try
//
// Now if bar() throws, it is going to end up ip in bb2, when it is supposed
// throw up to the caller. We solve this problem in the same way, but in this
// case 'delegate's immediate argument is the number of block depths + 1,
// which means it rethrows to the caller.
// try
// call @foo
// try ;; (new)
// call @bar
// delegate 1 (caller) ;; (new)
// catch ;; ehpad (bb2)
// ...
// end_try
//
// Before rewriteDepthImmediates, delegate's argument is a BB. In case of the
// caller, it will take a fake BB generated by getFakeCallerBlock(), which
// will be converted to a correct immediate argument later.
//
// In case there are multiple calls in a BB that may throw to the caller, they
// can be wrapped together in one nested try-delegate scope. (In 1, this
// couldn't happen, because may-throwing instruction there had an unwind
// destination, i.e., it was an invoke before, and there could be only one
// invoke within a BB.)
SmallVector<const MachineBasicBlock *, 8> EHPadStack;
// Range of intructions to be wrapped in a new nested try/catch. A range
// exists in a single BB and does not span multiple BBs.
using TryRange = std::pair<MachineInstr *, MachineInstr *>;
// In original CFG, <unwind destination BB, a vector of try ranges>
DenseMap<MachineBasicBlock *, SmallVector<TryRange, 4>> UnwindDestToTryRanges;
// Gather possibly throwing calls (i.e., previously invokes) whose current
// unwind destination is not the same as the original CFG. (Case 1)
for (auto &MBB : reverse(MF)) {
bool SeenThrowableInstInBB = false;
for (auto &MI : reverse(MBB)) {
if (MI.getOpcode() == WebAssembly::TRY)
EHPadStack.pop_back();
else if (WebAssembly::isCatch(MI.getOpcode()))
EHPadStack.push_back(MI.getParent());
// In this loop we only gather calls that have an EH pad to unwind. So
// there will be at most 1 such call (= invoke) in a BB, so after we've
// seen one, we can skip the rest of BB. Also if MBB has no EH pad
// successor or MI does not throw, this is not an invoke.
if (SeenThrowableInstInBB || !MBB.hasEHPadSuccessor() ||
!WebAssembly::mayThrow(MI))
continue;
SeenThrowableInstInBB = true;
// If the EH pad on the stack top is where this instruction should unwind
// next, we're good.
MachineBasicBlock *UnwindDest = getFakeCallerBlock(MF);
for (auto *Succ : MBB.successors()) {
// Even though semantically a BB can have multiple successors in case an
// exception is not caught by a catchpad, in our backend implementation
// it is guaranteed that a BB can have at most one EH pad successor. For
// details, refer to comments in findWasmUnwindDestinations function in
// SelectionDAGBuilder.cpp.
if (Succ->isEHPad()) {
UnwindDest = Succ;
break;
}
}
if (EHPadStack.back() == UnwindDest)
continue;
// Include EH_LABELs in the range before and afer the invoke
MachineInstr *RangeBegin = &MI, *RangeEnd = &MI;
if (RangeBegin->getIterator() != MBB.begin() &&
std::prev(RangeBegin->getIterator())->isEHLabel())
RangeBegin = &*std::prev(RangeBegin->getIterator());
if (std::next(RangeEnd->getIterator()) != MBB.end() &&
std::next(RangeEnd->getIterator())->isEHLabel())
RangeEnd = &*std::next(RangeEnd->getIterator());
// If not, record the range.
UnwindDestToTryRanges[UnwindDest].push_back(
TryRange(RangeBegin, RangeEnd));
LLVM_DEBUG(dbgs() << "- Call unwind mismatch: MBB = " << MBB.getName()
<< "\nCall = " << MI
<< "\nOriginal dest = " << UnwindDest->getName()
<< " Current dest = " << EHPadStack.back()->getName()
<< "\n\n");
}
}
assert(EHPadStack.empty());
// Gather possibly throwing calls that are supposed to unwind up to the caller
// if they throw, but currently unwind to an incorrect destination. Unlike the
// loop above, there can be multiple calls within a BB that unwind to the
// caller, which we should group together in a range. (Case 2)
MachineInstr *RangeBegin = nullptr, *RangeEnd = nullptr; // inclusive
// Record the range.
auto RecordCallerMismatchRange = [&](const MachineBasicBlock *CurrentDest) {
UnwindDestToTryRanges[getFakeCallerBlock(MF)].push_back(
TryRange(RangeBegin, RangeEnd));
LLVM_DEBUG(dbgs() << "- Call unwind mismatch: MBB = "
<< RangeBegin->getParent()->getName()
<< "\nRange begin = " << *RangeBegin
<< "Range end = " << *RangeEnd
<< "\nOriginal dest = caller Current dest = "
<< CurrentDest->getName() << "\n\n");
RangeBegin = RangeEnd = nullptr; // Reset range pointers
};
for (auto &MBB : reverse(MF)) {
bool SeenThrowableInstInBB = false;
for (auto &MI : reverse(MBB)) {
if (MI.getOpcode() == WebAssembly::TRY)
EHPadStack.pop_back();
else if (WebAssembly::isCatch(MI.getOpcode()))
EHPadStack.push_back(MI.getParent());
bool MayThrow = WebAssembly::mayThrow(MI);
// If MBB has an EH pad successor and this is the last instruction that
// may throw, this instruction unwinds to the EH pad and not to the
// caller.
if (MBB.hasEHPadSuccessor() && MayThrow && !SeenThrowableInstInBB) {
SeenThrowableInstInBB = true;
continue;
}
// We wrap up the current range when we see a marker even if we haven't
// finished a BB.
if (RangeEnd && WebAssembly::isMarker(MI.getOpcode())) {
RecordCallerMismatchRange(EHPadStack.back());
continue;
}
// If EHPadStack is empty, that means it correctly unwinds to the caller
// if it throws, so we're good. If MI does not throw, we're good too.
if (EHPadStack.empty() || !MayThrow)
continue;
// We found an instruction that unwinds to the caller but currently has an
// incorrect unwind destination. Create a new range or increment the
// currently existing range.
if (!RangeEnd)
RangeBegin = RangeEnd = &MI;
else
RangeBegin = &MI;
}
if (RangeEnd)
RecordCallerMismatchRange(EHPadStack.back());
}
assert(EHPadStack.empty());
// We don't have any unwind destination mismatches to resolve.
if (UnwindDestToTryRanges.empty())
return false;
// Now we fix the mismatches by wrapping calls with inner try-delegates.
for (auto &P : UnwindDestToTryRanges) {
NumCallUnwindMismatches += P.second.size();
MachineBasicBlock *UnwindDest = P.first;
auto &TryRanges = P.second;
for (auto Range : TryRanges) {
MachineInstr *RangeBegin = nullptr, *RangeEnd = nullptr;
std::tie(RangeBegin, RangeEnd) = Range;
auto *MBB = RangeBegin->getParent();
// If this BB has an EH pad successor, i.e., ends with an 'invoke', now we
// are going to wrap the invoke with try-delegate, making the 'delegate'
// BB the new successor instead, so remove the EH pad succesor here. The
// BB may not have an EH pad successor if calls in this BB throw to the
// caller.
MachineBasicBlock *EHPad = nullptr;
for (auto *Succ : MBB->successors()) {
if (Succ->isEHPad()) {
EHPad = Succ;
break;
}
}
if (EHPad)
MBB->removeSuccessor(EHPad);
addTryDelegate(RangeBegin, RangeEnd, UnwindDest);
}
}
return true;
}
bool WebAssemblyCFGStackify::fixCatchUnwindMismatches(MachineFunction &MF) {
// TODO implement
return false;
}
static unsigned
getDepth(const SmallVectorImpl<const MachineBasicBlock *> &Stack,
void WebAssemblyCFGStackify::recalculateScopeTops(MachineFunction &MF) {
// Renumber BBs and recalculate ScopeTop info because new BBs might have been
// created and inserted during fixing unwind mismatches.
MF.RenumberBlocks();
ScopeTops.clear();
ScopeTops.resize(MF.getNumBlockIDs());
for (auto &MBB : reverse(MF)) {
for (auto &MI : reverse(MBB)) {
if (ScopeTops[MBB.getNumber()])
break;
switch (MI.getOpcode()) {
case WebAssembly::END_BLOCK:
case WebAssembly::END_LOOP:
case WebAssembly::END_TRY:
case WebAssembly::DELEGATE:
updateScopeTops(EndToBegin[&MI]->getParent(), &MBB);
break;
case WebAssembly::CATCH:
case WebAssembly::CATCH_ALL:
updateScopeTops(EHPadToTry[&MBB]->getParent(), &MBB);
break;
}
}
}
}
unsigned WebAssemblyCFGStackify::getDepth(
const SmallVectorImpl<const MachineBasicBlock *> &Stack,
const MachineBasicBlock *MBB) {
if (MBB == FakeCallerBB)
return Stack.size();
unsigned Depth = 0;
for (auto X : reverse(Stack)) {
if (X == MBB)
@ -937,13 +1357,18 @@ void WebAssemblyCFGStackify::placeMarkers(MachineFunction &MF) {
}
// Fix mismatches in unwind destinations induced by linearizing the code.
if (MCAI->getExceptionHandlingType() == ExceptionHandling::Wasm &&
MF.getFunction().hasPersonalityFn())
fixUnwindMismatches(MF);
MF.getFunction().hasPersonalityFn()) {
bool Changed = fixCallUnwindMismatches(MF);
Changed |= fixCatchUnwindMismatches(MF);
if (Changed)
recalculateScopeTops(MF);
}
}
void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
// Now rewrite references to basic blocks to be depth immediates.
SmallVector<const MachineBasicBlock *, 8> Stack;
SmallVector<const MachineBasicBlock *, 8> DelegateStack;
for (auto &MBB : reverse(MF)) {
for (auto I = MBB.rbegin(), E = MBB.rend(); I != E; ++I) {
MachineInstr &MI = *I;
@ -954,20 +1379,34 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
MBB.getNumber() &&
"Block/try marker should be balanced");
Stack.pop_back();
DelegateStack.pop_back();
break;
case WebAssembly::LOOP:
assert(Stack.back() == &MBB && "Loop top should be balanced");
Stack.pop_back();
DelegateStack.pop_back();
break;
case WebAssembly::END_BLOCK:
Stack.push_back(&MBB);
DelegateStack.push_back(&MBB);
break;
case WebAssembly::END_TRY:
// We handle DELEGATE in the default level, because DELEGATE has
// immediate operands to rewirte.
Stack.push_back(&MBB);
break;
case WebAssembly::END_LOOP:
Stack.push_back(EndToBegin[&MI]->getParent());
DelegateStack.push_back(EndToBegin[&MI]->getParent());
break;
case WebAssembly::CATCH:
case WebAssembly::CATCH_ALL:
DelegateStack.push_back(&MBB);
break;
default:
@ -977,11 +1416,21 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
while (MI.getNumOperands() > 0)
MI.RemoveOperand(MI.getNumOperands() - 1);
for (auto MO : Ops) {
if (MO.isMBB())
if (MO.isMBB()) {
if (MI.getOpcode() == WebAssembly::DELEGATE)
MO = MachineOperand::CreateImm(
getDepth(DelegateStack, MO.getMBB()));
else
MO = MachineOperand::CreateImm(getDepth(Stack, MO.getMBB()));
}
MI.addOperand(MF, MO);
}
}
if (MI.getOpcode() == WebAssembly::DELEGATE) {
Stack.push_back(&MBB);
DelegateStack.push_back(&MBB);
}
break;
}
}
@ -989,13 +1438,18 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
assert(Stack.empty() && "Control flow should be balanced");
}
void WebAssemblyCFGStackify::cleanupFunctionData(MachineFunction &MF) {
if (FakeCallerBB)
MF.DeleteMachineBasicBlock(FakeCallerBB);
AppendixBB = FakeCallerBB = nullptr;
}
void WebAssemblyCFGStackify::releaseMemory() {
ScopeTops.clear();
BeginToEnd.clear();
EndToBegin.clear();
TryToEHPad.clear();
EHPadToTry.clear();
AppendixBB = nullptr;
}
bool WebAssemblyCFGStackify::runOnMachineFunction(MachineFunction &MF) {
@ -1031,6 +1485,8 @@ bool WebAssemblyCFGStackify::runOnMachineFunction(MachineFunction &MF) {
.isOSBinFormatELF())
appendEndToFunction(MF, TII);
cleanupFunctionData(MF);
MF.getInfo<WebAssemblyFunctionInfo>()->setCFGStackified();
return true;
}

4
llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
View File

@ -156,6 +156,10 @@ defm CATCH : I<(outs I32:$dst), (ins event_op:$tag),
defm CATCH_ALL : NRI<(outs), (ins), [], "catch_all", 0x05>;
}
// Delegating an exception: delegate
let isTerminator = 1, hasCtrlDep = 1, hasSideEffects = 1 in
defm DELEGATE : NRI<(outs), (ins bb_op:$dst), [], "delegate \t $dst", 0x18>;
// Pseudo instructions: cleanupret / catchret
let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
isPseudo = 1, isEHScopeReturn = 1 in {

320
llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
View File

@ -1,11 +1,9 @@
; REQUIRES: asserts
; TODO Reenable disabled lines after updating the backend to the new spec
; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling | FileCheck %s
; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling
; RUN: llc < %s -O0 -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -verify-machineinstrs -exception-model=wasm -mattr=+exception-handling | FileCheck %s --check-prefix=NOOPT
; R UN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort | FileCheck %s --check-prefix=NOSORT
; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort -stats 2>&1 | FileCheck %s --check-prefix=NOSORT
; RUN: llc < %s -disable-wasm-fallthrough-return-opt -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort | FileCheck %s --check-prefix=NOSORT-LOCALS
; R UN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling -wasm-disable-ehpad-sort -stats 2>&1 | FileCheck %s --check-prefix=NOSORT-STAT
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
@ -381,30 +379,23 @@ try.cont: ; preds = %catch.start, %loop
; destination mismatches. And we use -wasm-disable-ehpad-sort to create maximum
; number of mismatches in several tests below.
; 'call bar''s original unwind destination was 'C1', but after control flow
; linearization, its unwind destination incorrectly becomes 'C0'. We fix this by
; wrapping the call with a nested try/catch/end_try and branching to the right
; destination (L0).
; 'call bar''s original unwind destination was 'C0', but after control flow
; linearization, its unwind destination incorrectly becomes 'C1'. We fix this by
; wrapping the call with a nested try-delegate that targets 'C0'.
; NOSORT-LABEL: test5
; NOSORT: block
; NOSORT: try
; NOSORT: try
; NOSORT: call foo
; --- Nested try/catch/end_try starts
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call bar
; NOSORT: catch $drop=
; NOSORT: br 2 # 2: down to label[[L0:[0-9]+]]
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: down to catch[[C0:[0-9]+]]
; --- try-delegate ends (call unwind mismatch)
; NOSORT: catch {{.*}} # catch[[C1:[0-9]+]]:
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: br 2 # 2: down to label[[L1:[0-9]+]]
; NOSORT: catch $drop= # catch[[C0:[0-9]+]]:
; NOSORT: br 2 # 2: down to label[[L1]]
; NOSORT: catch {{.*}} # catch[[C0]]:
; NOSORT: end_try
; NOSORT: catch $drop= # catch[[C1:[0-9]+]]:
; NOSORT: end_try # label[[L0]]:
; NOSORT: end_block # label[[L1]]:
; NOSORT: return
define void @test5() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
@ -438,10 +429,10 @@ try.cont: ; preds = %catch.start1, %catc
ret void
}
; Two 'call bar''s original unwind destination was the caller, but after control
; flow linearization, their unwind destination incorrectly becomes 'C0'. We fix
; this by wrapping the call with a nested try/catch/end_try and branching to the
; right destination (L0), from which we rethrow the exception to the caller.
; 'call bar' and 'call baz''s original unwind destination was the caller, but
; after control flow linearization, their unwind destination incorrectly becomes
; 'C0'. We fix this by wrapping the calls with a nested try-delegate that
; rethrows exceptions to the caller.
; And the return value of 'baz' should NOT be stackified because the BB is split
; during fixing unwind mismatches.
@ -449,20 +440,18 @@ try.cont: ; preds = %catch.start1, %catc
; NOSORT-LABEL: test6
; NOSORT: try
; NOSORT: call foo
; --- Nested try/catch/end_try starts
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call bar
; NOSORT: call ${{[0-9]+}}=, baz
; NOSORT: call $[[RET:[0-9]+]]=, baz
; NOSORT-NOT: call $push{{.*}}=, baz
; NOSORT: catch $[[REG:[0-9]+]]=
; NOSORT: br 1 # 1: down to label[[L0:[0-9]+]]
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: to caller
; --- try-delegate ends (call unwind mismatch)
; NOSORT: call nothrow, $[[RET]]
; NOSORT: return
; NOSORT: catch {{.*}} # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: return
; NOSORT: catch $drop= # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try # label[[L0]]:
; NOSORT: rethrow $[[REG]] # to caller
define void @test6() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
bb0:
@ -488,34 +477,86 @@ try.cont: ; preds = %catch.start0
ret void
}
; The same as test5, but we have one more call 'call @foo' in bb1 which unwinds
; to the caller. IN this case bb1 has two call unwind mismatches: 'call @foo'
; unwinds to the caller and 'call @bar' unwinds to catch C0.
; NOSORT-LABEL: test7
; NOSORT: try
; NOSORT: try
; NOSORT: call foo
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call foo
; NOSORT: delegate 2 # label/catch{{[0-9]+}}: to caller
; --- try-delegate ends (call unwind mismatch)
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call bar
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: down to catch[[C0:[0-9]+]]
; --- try-delegate ends (call unwind mismatch)
; NOSORT: catch {{.*}} # catch[[C1:[0-9]+]]:
; NOSORT: end_try
; NOSORT: catch {{.*}} # catch[[C0]]:
; NOSORT: end_try
; NOSORT: return
define void @test7() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0
bb1: ; preds = %bb0
call void @foo()
invoke void @bar()
to label %try.cont unwind label %catch.dispatch1
catch.dispatch0: ; preds = %bb0
%0 = catchswitch within none [label %catch.start0] unwind to caller
catch.start0: ; preds = %catch.dispatch0
%1 = catchpad within %0 [i8* null]
%2 = call i8* @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %try.cont
catch.dispatch1: ; preds = %bb1
%4 = catchswitch within none [label %catch.start1] unwind to caller
catch.start1: ; preds = %catch.dispatch1
%5 = catchpad within %4 [i8* null]
%6 = call i8* @llvm.wasm.get.exception(token %5)
%7 = call i32 @llvm.wasm.get.ehselector(token %5)
catchret from %5 to label %try.cont
try.cont: ; preds = %catch.start1, %catch.start0, %bb1
ret void
}
; Similar situation as @test6. Here 'call @qux''s original unwind destination
; was the caller, but after control flow linearization, their unwind destination
; incorrectly becomes 'C0' within the function. We fix this by wrapping the call
; with a nested try/catch/end_try and branching to the right destination, from
; which we rethrow the exception to the caller.
; with a nested try-delegate that rethrows the exception to the caller.
; Because 'call @qux' pops an argument pushed by 'i32.const 5' from stack, the
; nested 'try' should be placed before `i32.const 5', not between 'i32.const 5'
; and 'call @qux'.
; NOSORT-LABEL: test7
; NOSORT: try
; NOSORT-LABEL: test8
; NOSORT: try i32
; NOSORT: call foo
; --- Nested try/catch/end_try starts
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT-NEXT: i32.const $push{{[0-9]+}}=, 5
; NOSORT-NEXT: call ${{[0-9]+}}=, qux
; NOSORT: catch $[[REG:[0-9]+]]=
; NOSORT: br 1 # 1: down to label[[L0:[0-9]+]]
; NOSORT: i32.const $push{{[0-9]+}}=, 5
; NOSORT: call ${{[0-9]+}}=, qux
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: to caller
; --- try-delegate ends (call unwind mismatch)
; NOSORT: return
; NOSORT: catch {{.*}} # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: return
; NOSORT: catch $drop= # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try # label[[L0]]:
; NOSORT: rethrow $[[REG]] # to caller
define i32 @test7() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
define i32 @test8() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0
@ -538,10 +579,10 @@ try.cont: ; preds = %catch.start0
}
; Tests the case when TEE stackifies a register in RegStackify but it gets
; unstackified in fixUnwindMismatches in CFGStackify.
; unstackified in fixCallUnwindMismatches in CFGStackify.
; NOSORT-LOCALS-LABEL: test8
define void @test8(i32 %x) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
; NOSORT-LOCALS-LABEL: test9
define void @test9(i32 %x) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0
@ -551,7 +592,7 @@ bb1: ; preds = %bb0
; This %addr is used in multiple places, so tee is introduced in RegStackify,
; which stackifies the use of %addr in store instruction. A tee has two dest
; registers, the first of which is stackified and the second is not.
; But when we introduce a nested try-catch in fixUnwindMismatches in
; But when we introduce a nested try-delegate in fixCallUnwindMismatches in
; CFGStackify, it is possible that we end up unstackifying the first dest
; register. In that case, we convert that tee into a copy.
%addr = inttoptr i32 %t to i32*
@ -577,62 +618,6 @@ try.cont: ; preds = %catch.start0
ret void
}
; If not for the unwind destination mismatch, the LOOP marker here would have an
; i32 signature. But because we add a rethrow instruction at the end of the
; appendix block, now the LOOP marker does not have a signature (= has a void
; signature). Here the two calls two 'bar' are supposed to throw up to the
; caller, but incorrectly unwind to 'C0' after linearizing the CFG.
; NOSORT-LABEL: test9
; NOSORT: block
; NOSORT-NOT: loop i32
; NOSORT: loop # label[[L0:[0-9]+]]:
; NOSORT: try
; NOSORT: call foo
; --- Nested try/catch/end_try starts
; NOSORT: try
; NOSORT: call bar
; NOSORT: call bar
; NOSORT: catch $[[REG:[0-9]+]]=
; NOSORT: br 1 # 1: down to label[[L1:[0-9]+]]
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: return {{.*}}
; NOSORT: catch $drop= # catch[[C0:[0-9]+]]:
; NOSORT: br 1 # 1: up to label[[L0]]
; NOSORT: end_try # label[[L1]]:
; NOSORT: end_loop
; NOSORT: end_block
; NOSORT: rethrow $[[REG]] # to caller
define i32 @test9(i32* %p) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
store volatile i32 0, i32* %p
br label %loop
loop: ; preds = %try.cont, %entry
store volatile i32 1, i32* %p
invoke void @foo()
to label %bb unwind label %catch.dispatch
bb: ; preds = %loop
call void @bar()
call void @bar()
ret i32 0
catch.dispatch: ; preds = %loop
%0 = catchswitch within none [label %catch.start] unwind to caller
catch.start: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* null]
%2 = call i8* @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %try.cont
try.cont: ; preds = %catch.start
br label %loop
}
; When we have both kinds of EH pad unwind mismatches:
; - A may-throw instruction unwinds to an incorrect EH pad after linearizing the
; CFG, when it is supposed to unwind to another EH pad.
@ -640,48 +625,28 @@ try.cont: ; preds = %catch.start
; CFG, when it is supposed to unwind to the caller.
; NOSORT-LABEL: test10
; NOSORT: block
; NOSORT: block
; NOSORT: try
; NOSORT: try
; NOSORT: call foo
; --- Nested try/catch/end_try starts
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call bar
; NOSORT: catch $[[REG0:[0-9]+]]=
; NOSORT: br 2 # 2: down to label[[L0:[0-9]+]]
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: br 2 # 2: down to label[[L1:[0-9]+]]
; NOSORT: catch {{.*}}
; NOSORT: block i32
; NOSORT: br_on_exn 0, {{.*}} # 0: down to label[[L2:[0-9]+]]
; --- Nested try/catch/end_try starts
; NOSORT: try
; NOSORT: rethrow 0 # down to catch[[C0:[0-9]+]]
; NOSORT: catch $[[REG1:[0-9]+]]= # catch[[C0]]:
; NOSORT: br 5 # 5: down to label[[L3:[0-9]+]]
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: end_block # label[[L2]]:
; NOSORT: call $drop=, __cxa_begin_catch
; --- Nested try/catch/end_try starts
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: down to catch[[C0:[0-9]+]]
; --- try-delegate ends (call unwind mismatch)
; NOSORT: catch
; NOSORT: call {{.*}} __cxa_begin_catch
; --- try-delegate starts (call unwind mismatch)
; NOSORT: try
; NOSORT: call __cxa_end_catch
; NOSORT: catch $[[REG1]]=
; NOSORT: br 4 # 4: down to label[[L3]]
; NOSORT: delegate 1 # label/catch{{[0-9]+}}: to caller
; --- try-delegate ends (call unwind mismatch)
; NOSORT: end_try
; --- Nested try/catch/end_try ends
; NOSORT: br 2 # 2: down to label[[L1]]
; NOSORT: end_try
; NOSORT: catch $[[REG0]]=
; NOSORT: end_try # label[[L0]]:
; NOSORT: call $drop=, __cxa_begin_catch
; NOSORT: catch {{.*}} # catch[[C0]]:
; NOSORT: call {{.*}} __cxa_begin_catch
; NOSORT: call __cxa_end_catch
; NOSORT: end_block # label[[L1]]:
; NOSORT: end_try
; NOSORT: return
; NOSORT: end_block # label[[L3]]:
; NOSORT: rethrow $[[REG1]] # to caller
define void @test10() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
bb0:
invoke void @foo()
@ -724,6 +689,7 @@ try.cont: ; preds = %catch.start1, %catc
; (before 'cont' is sorted) and there should not be any unwind destination
; mismatches in CFGStackify.
; NOOPT-LABEL: test11
; NOOPT: block
; NOOPT: try
; NOOPT: call foo
@ -774,8 +740,8 @@ if.end: ; preds = %cont, %catch.start,
; NOSORT: call {{.*}} memmove
; NOSORT: call {{.*}} memset
; NOSORT: return
; NOSORT: catch
; NOSORT: rethrow
; NOSORT: catch_all
; NOSORT: rethrow 0
; NOSORT: end_try
define void @test12(i8* %a, i8* %b) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
@ -891,49 +857,6 @@ terminate7: ; preds = %ehcleanup
unreachable
}
; We don't need to call placeBlockMarker after fixUnwindMismatches unless the
; destination is the appendix BB at the very end. This should not crash.
define void @test16(i32* %p, i32 %a, i32 %b) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
br label %loop
loop: ; preds = %try.cont, %entry
invoke void @foo()
to label %bb0 unwind label %catch.dispatch0
bb0: ; preds = %loop
%cmp = icmp ne i32 %a, %b
br i1 %cmp, label %bb1, label %last
bb1: ; preds = %bb0
invoke void @bar()
to label %try.cont unwind label %catch.dispatch1
catch.dispatch0: ; preds = %loop
%0 = catchswitch within none [label %catch.start0] unwind to caller
catch.start0: ; preds = %catch.dispatch0
%1 = catchpad within %0 [i8* null]
%2 = call i8* @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %try.cont
catch.dispatch1: ; preds = %bb1
%4 = catchswitch within none [label %catch.start1] unwind to caller
catch.start1: ; preds = %catch.dispatch1
%5 = catchpad within %4 [i8* null]
%6 = call i8* @llvm.wasm.get.exception(token %5)
%7 = call i32 @llvm.wasm.get.ehselector(token %5)
catchret from %5 to label %try.cont
try.cont: ; preds = %catch.start1, %catch.start0, %bb1
br label %loop
last: ; preds = %bb0
ret void
}
; Tests if CFGStackify's removeUnnecessaryInstrs() removes unnecessary branches
; correctly. The code is in the form below, where 'br' is unnecessary because
; after running the 'try' body the control flow will fall through to bb2 anyway.
@ -947,8 +870,8 @@ last: ; preds = %bb0
; ...
; bb2: <- Continuation BB
; end
; CHECK-LABEL: test17
define void @test17(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
; CHECK-LABEL: test15
define void @test15(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
invoke void @foo()
to label %for.body unwind label %catch.dispatch
@ -986,7 +909,7 @@ try.cont: ; preds = %catch.start, %for.e
}
; void foo();
; void test18() {
; void test16() {
; try {
; foo();
; try {
@ -1016,8 +939,8 @@ try.cont: ; preds = %catch.start, %for.e
; bb3: <- Continuation BB
; end
;
; CHECK-LABEL: test18
define void @test18() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
; CHECK-LABEL: test16
define void @test16() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
; CHECK: call foo
entry:
invoke void @foo()
@ -1064,12 +987,12 @@ invoke.cont2: ; preds = %catch.start
; path back to the loop header), and is placed after the loop latch block
; 'invoke.cont' intentionally. This tests if 'end_loop' marker is placed
; correctly not right after 'invoke.cont' part but after 'ehcleanup' part,
; NOSORT-LABEL: test19
; NOSORT-LABEL: test17
; NOSORT: loop
; NOSORT: try
; NOSORT: end_try
; NOSORT: end_loop
define void @test19(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
define void @test17(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
br label %while.cond
@ -1111,17 +1034,17 @@ while.end: ; preds = %while.body, %while.
; very end of a function, CFGStackify's fixEndsAtEndOfFunction function fixes
; the corresponding block/loop/try's type to match the function's return type.
; But when a `try`'s type is fixed, we should also check `end` instructions
; before its corresponding `catch`, because both `try` and `catch` body should
; satisfy the return type requirements.
; before its corresponding `catch_all`, because both `try` and `catch_all` body
; should satisfy the return type requirements.
; NOSORT-LABEL: test20
; NOSORT-LABEL: test18
; NOSORT: try i32
; NOSORT: loop i32
; NOSORT: end_loop
; NOSORT: catch
; NOSORT: catch_all
; NOSORT: end_try
; NOSORT-NEXT: end_function
define i32 @test20(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
define i32 @test18(i32 %n) personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
%t = alloca %class.Object, align 1
br label %for.cond
@ -1154,9 +1077,8 @@ ehcleanup: ; preds = %if.then
cleanupret from %0 unwind to caller
}
; Check if the unwind destination mismatch stats are correct
; NOSORT-STAT: 17 wasm-cfg-stackify - Number of EH pad unwind mismatches found
; NOSORT: 18 wasm-cfg-stackify - Number of call unwind mismatches found
declare void @foo()
declare void @bar()