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Diffstat (limited to 'llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp')
-rw-r--r--llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp141
1 files changed, 67 insertions, 74 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
index c7001ef..6fd882f 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -63,8 +63,9 @@ class WebAssemblyCFGStackify final : public MachineFunctionPass {
// over scoped regions when walking blocks.
SmallVector<MachineBasicBlock *, 8> ScopeTops;
void updateScopeTops(MachineBasicBlock *Begin, MachineBasicBlock *End) {
+ int BeginNo = Begin->getNumber();
int EndNo = End->getNumber();
- if (!ScopeTops[EndNo] || ScopeTops[EndNo]->getNumber() > Begin->getNumber())
+ if (!ScopeTops[EndNo] || ScopeTops[EndNo]->getNumber() > BeginNo)
ScopeTops[EndNo] = Begin;
}
@@ -77,8 +78,8 @@ class WebAssemblyCFGStackify final : public MachineFunctionPass {
// Exception handling related functions
bool fixCallUnwindMismatches(MachineFunction &MF);
bool fixCatchUnwindMismatches(MachineFunction &MF);
- void addTryDelegate(MachineInstr *RangeBegin, MachineInstr *RangeEnd,
- MachineBasicBlock *DelegateDest);
+ void addNestedTryDelegate(MachineInstr *RangeBegin, MachineInstr *RangeEnd,
+ MachineBasicBlock *UnwindDest);
void recalculateScopeTops(MachineFunction &MF);
void removeUnnecessaryInstrs(MachineFunction &MF);
@@ -225,7 +226,7 @@ void WebAssemblyCFGStackify::registerScope(MachineInstr *Begin,
EndToBegin[End] = Begin;
}
-// When 'End' is not an 'end_try' but 'delegate, EHPad is nullptr.
+// When 'End' is not an 'end_try' but a 'delegate', EHPad is nullptr.
void WebAssemblyCFGStackify::registerTryScope(MachineInstr *Begin,
MachineInstr *End,
MachineBasicBlock *EHPad) {
@@ -293,7 +294,7 @@ void WebAssemblyCFGStackify::placeBlockMarker(MachineBasicBlock &MBB) {
}
}
- // Decide where in Header to put the BLOCK.
+ // Decide where in MBB to put the BLOCK.
// Instructions that should go before the BLOCK.
SmallPtrSet<const MachineInstr *, 4> BeforeSet;
@@ -359,21 +360,20 @@ void WebAssemblyCFGStackify::placeBlockMarker(MachineBasicBlock &MBB) {
TII.get(WebAssembly::BLOCK))
.addImm(int64_t(ReturnType));
- // Decide where in Header to put the END_BLOCK.
+ // Decide where in MBB to put the END_BLOCK.
BeforeSet.clear();
AfterSet.clear();
for (auto &MI : MBB) {
#ifndef NDEBUG
- // END_BLOCK should precede existing LOOP and TRY markers.
- if (MI.getOpcode() == WebAssembly::LOOP ||
- MI.getOpcode() == WebAssembly::TRY)
+ // END_BLOCK should precede existing LOOP markers.
+ if (MI.getOpcode() == WebAssembly::LOOP)
AfterSet.insert(&MI);
#endif
// If there is a previously placed END_LOOP marker and the header of the
// loop is above this block's header, the END_LOOP should be placed after
- // the BLOCK, because the loop contains this block. Otherwise the END_LOOP
- // should be placed before the BLOCK. The same for END_TRY.
+ // the END_BLOCK, because the loop contains this block. Otherwise the
+ // END_LOOP should be placed before the END_BLOCK. The same for END_TRY.
if (MI.getOpcode() == WebAssembly::END_LOOP ||
MI.getOpcode() == WebAssembly::END_TRY) {
if (EndToBegin[&MI]->getParent()->getNumber() >= Header->getNumber())
@@ -437,7 +437,7 @@ void WebAssemblyCFGStackify::placeLoopMarker(MachineBasicBlock &MBB) {
TII.get(WebAssembly::LOOP))
.addImm(int64_t(WebAssembly::BlockType::Void));
- // Decide where in Header to put the END_LOOP.
+ // Decide where in MBB to put the END_LOOP.
BeforeSet.clear();
AfterSet.clear();
#ifndef NDEBUG
@@ -491,7 +491,6 @@ void WebAssemblyCFGStackify::placeTryMarker(MachineBasicBlock &MBB) {
WebAssemblyException *WE = WEI.getExceptionFor(&MBB);
assert(WE);
MachineBasicBlock *Bottom = SRI.getBottom(WE);
-
auto Iter = std::next(Bottom->getIterator());
if (Iter == MF.end()) {
getAppendixBlock(MF);
@@ -499,12 +498,9 @@ void WebAssemblyCFGStackify::placeTryMarker(MachineBasicBlock &MBB) {
}
MachineBasicBlock *Cont = &*Iter;
- assert(Cont != &MF.front());
- MachineBasicBlock *LayoutPred = Cont->getPrevNode();
-
// If the nearest common dominator is inside a more deeply nested context,
// walk out to the nearest scope which isn't more deeply nested.
- for (MachineFunction::iterator I(LayoutPred), E(Header); I != E; --I) {
+ for (MachineFunction::iterator I(Bottom), E(Header); I != E; --I) {
if (MachineBasicBlock *ScopeTop = ScopeTops[I->getNumber()]) {
if (ScopeTop->getNumber() > Header->getNumber()) {
// Skip over an intervening scope.
@@ -538,7 +534,7 @@ void WebAssemblyCFGStackify::placeTryMarker(MachineBasicBlock &MBB) {
}
// All previously inserted BLOCK/TRY markers should be after the TRY because
- // they are all nested trys.
+ // they are all nested blocks/trys.
if (MI.getOpcode() == WebAssembly::BLOCK ||
MI.getOpcode() == WebAssembly::TRY)
AfterSet.insert(&MI);
@@ -607,14 +603,13 @@ void WebAssemblyCFGStackify::placeTryMarker(MachineBasicBlock &MBB) {
TII.get(WebAssembly::TRY))
.addImm(int64_t(WebAssembly::BlockType::Void));
- // Decide where in Header to put the END_TRY.
+ // Decide where in Cont to put the END_TRY.
BeforeSet.clear();
AfterSet.clear();
for (const auto &MI : *Cont) {
#ifndef NDEBUG
- // END_TRY should precede existing LOOP and BLOCK markers.
- if (MI.getOpcode() == WebAssembly::LOOP ||
- MI.getOpcode() == WebAssembly::BLOCK)
+ // END_TRY should precede existing LOOP markers.
+ if (MI.getOpcode() == WebAssembly::LOOP)
AfterSet.insert(&MI);
// All END_TRY markers placed earlier belong to exceptions that contains
@@ -643,9 +638,8 @@ void WebAssemblyCFGStackify::placeTryMarker(MachineBasicBlock &MBB) {
// Mark the end of the TRY.
InsertPos = getEarliestInsertPos(Cont, BeforeSet, AfterSet);
- MachineInstr *End =
- BuildMI(*Cont, InsertPos, Bottom->findBranchDebugLoc(),
- TII.get(WebAssembly::END_TRY));
+ MachineInstr *End = BuildMI(*Cont, InsertPos, Bottom->findBranchDebugLoc(),
+ TII.get(WebAssembly::END_TRY));
registerTryScope(Begin, End, &MBB);
// Track the farthest-spanning scope that ends at this point. We create two
@@ -845,9 +839,9 @@ static void unstackifyVRegsUsedInSplitBB(MachineBasicBlock &MBB,
// Wrap the given range of instruction with try-delegate. RangeBegin and
// RangeEnd are inclusive.
-void WebAssemblyCFGStackify::addTryDelegate(MachineInstr *RangeBegin,
- MachineInstr *RangeEnd,
- MachineBasicBlock *DelegateDest) {
+void WebAssemblyCFGStackify::addNestedTryDelegate(
+ MachineInstr *RangeBegin, MachineInstr *RangeEnd,
+ MachineBasicBlock *UnwindDest) {
auto *BeginBB = RangeBegin->getParent();
auto *EndBB = RangeEnd->getParent();
MachineFunction &MF = *BeginBB->getParent();
@@ -879,8 +873,8 @@ void WebAssemblyCFGStackify::addTryDelegate(MachineInstr *RangeBegin,
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);
+ if (UnwindDest != FakeCallerBB)
+ DelegateBB->addSuccessor(UnwindDest);
auto SplitPos = std::next(RangeEnd->getIterator());
if (SplitPos == EndBB->end()) {
@@ -962,7 +956,7 @@ void WebAssemblyCFGStackify::addTryDelegate(MachineInstr *RangeBegin,
// Add 'delegate' instruction in the delegate BB created above.
MachineInstr *Delegate = BuildMI(DelegateBB, RangeEnd->getDebugLoc(),
TII.get(WebAssembly::DELEGATE))
- .addMBB(DelegateDest);
+ .addMBB(UnwindDest);
registerTryScope(Try, Delegate, nullptr);
}
@@ -1130,7 +1124,7 @@ bool WebAssemblyCFGStackify::fixCallUnwindMismatches(MachineFunction &MF) {
if (EHPadStack.back() == UnwindDest)
continue;
- // Include EH_LABELs in the range before and afer the invoke
+ // Include EH_LABELs in the range before and after the invoke
MachineInstr *RangeBegin = &MI, *RangeEnd = &MI;
if (RangeBegin->getIterator() != MBB.begin() &&
std::prev(RangeBegin->getIterator())->isEHLabel())
@@ -1231,22 +1225,24 @@ bool WebAssemblyCFGStackify::fixCallUnwindMismatches(MachineFunction &MF) {
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 this BB has an EH pad successor, i.e., ends with an 'invoke', and if
+ // the current range contains the 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.
+ if (UnwindDest != getFakeCallerBlock(MF)) {
+ MachineBasicBlock *EHPad = nullptr;
+ for (auto *Succ : MBB->successors()) {
+ if (Succ->isEHPad()) {
+ EHPad = Succ;
+ break;
+ }
}
+ if (EHPad)
+ MBB->removeSuccessor(EHPad);
}
- if (EHPad)
- MBB->removeSuccessor(EHPad);
- addTryDelegate(RangeBegin, RangeEnd, UnwindDest);
+ addNestedTryDelegate(RangeBegin, RangeEnd, UnwindDest);
}
}
@@ -1354,12 +1350,10 @@ bool WebAssemblyCFGStackify::fixCatchUnwindMismatches(MachineFunction &MF) {
NumCatchUnwindMismatches += EHPadToUnwindDest.size();
SmallPtrSet<MachineBasicBlock *, 4> NewEndTryBBs;
- for (auto &P : EHPadToUnwindDest) {
- MachineBasicBlock *EHPad = P.first;
- MachineBasicBlock *UnwindDest = P.second;
+ for (auto &[EHPad, UnwindDest] : EHPadToUnwindDest) {
MachineInstr *Try = EHPadToTry[EHPad];
MachineInstr *EndTry = BeginToEnd[Try];
- addTryDelegate(Try, EndTry, UnwindDest);
+ addNestedTryDelegate(Try, EndTry, UnwindDest);
NewEndTryBBs.insert(EndTry->getParent());
}
@@ -1534,7 +1528,7 @@ static void appendEndToFunction(MachineFunction &MF,
TII.get(WebAssembly::END_FUNCTION));
}
-/// Insert LOOP/TRY/BLOCK markers at appropriate places.
+/// Insert BLOCK/LOOP/TRY markers at appropriate places.
void WebAssemblyCFGStackify::placeMarkers(MachineFunction &MF) {
// We allocate one more than the number of blocks in the function to
// accommodate for the possible fake block we may insert at the end.
@@ -1558,9 +1552,9 @@ void WebAssemblyCFGStackify::placeMarkers(MachineFunction &MF) {
// Fix mismatches in unwind destinations induced by linearizing the code.
if (MCAI->getExceptionHandlingType() == ExceptionHandling::Wasm &&
MF.getFunction().hasPersonalityFn()) {
- bool Changed = fixCallUnwindMismatches(MF);
- Changed |= fixCatchUnwindMismatches(MF);
- if (Changed)
+ bool MismatchFixed = fixCallUnwindMismatches(MF);
+ MismatchFixed |= fixCatchUnwindMismatches(MF);
+ if (MismatchFixed)
recalculateScopeTops(MF);
}
}
@@ -1654,6 +1648,23 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
// Now rewrite references to basic blocks to be depth immediates.
SmallVector<EndMarkerInfo, 8> Stack;
SmallVector<const MachineBasicBlock *, 8> EHPadStack;
+
+ auto RewriteOperands = [&](MachineInstr &MI) {
+ // Rewrite MBB operands to be depth immediates.
+ SmallVector<MachineOperand, 4> Ops(MI.operands());
+ while (MI.getNumOperands() > 0)
+ MI.removeOperand(MI.getNumOperands() - 1);
+ for (auto MO : Ops) {
+ if (MO.isMBB()) {
+ if (MI.getOpcode() == WebAssembly::DELEGATE)
+ MO = MachineOperand::CreateImm(getDelegateDepth(Stack, MO.getMBB()));
+ else
+ MO = MachineOperand::CreateImm(getBranchDepth(Stack, MO.getMBB()));
+ }
+ MI.addOperand(MF, MO);
+ }
+ };
+
for (auto &MBB : reverse(MF)) {
for (MachineInstr &MI : llvm::reverse(MBB)) {
switch (MI.getOpcode()) {
@@ -1697,23 +1708,8 @@ void WebAssemblyCFGStackify::rewriteDepthImmediates(MachineFunction &MF) {
break;
default:
- if (MI.isTerminator()) {
- // Rewrite MBB operands to be depth immediates.
- SmallVector<MachineOperand, 4> Ops(MI.operands());
- while (MI.getNumOperands() > 0)
- MI.removeOperand(MI.getNumOperands() - 1);
- for (auto MO : Ops) {
- if (MO.isMBB()) {
- if (MI.getOpcode() == WebAssembly::DELEGATE)
- MO = MachineOperand::CreateImm(
- getDelegateDepth(Stack, MO.getMBB()));
- else
- MO = MachineOperand::CreateImm(
- getBranchDepth(Stack, MO.getMBB()));
- }
- MI.addOperand(MF, MO);
- }
- }
+ if (MI.isTerminator())
+ RewriteOperands(MI);
if (MI.getOpcode() == WebAssembly::DELEGATE)
Stack.push_back(std::make_pair(&MBB, &MI));
@@ -1767,10 +1763,7 @@ bool WebAssemblyCFGStackify::runOnMachineFunction(MachineFunction &MF) {
// Add an end instruction at the end of the function body.
const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
- if (!MF.getSubtarget<WebAssemblySubtarget>()
- .getTargetTriple()
- .isOSBinFormatELF())
- appendEndToFunction(MF, TII);
+ appendEndToFunction(MF, TII);
cleanupFunctionData(MF);
generated by cgit v1.1 at 2025-09-30 13:44:35 +0000