Re-apply "Emit missing cleanups for stmt-expr" and other commits #89154
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…nsions" and related commits (llvm#88884) This reverts commit 9d8be24.
llvmbot
added
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-clang-codegen Author: Utkarsh Saxena (usx95) ChangesLatest diff: https://github.com/llvm/llvm-project/pull/89154/files/f1ab4c2677394bbfc985d9680d5eecd7b2e6a882..26bb3b19c551348de5bf88bd16f90b60c28a8a2b struct A { };
struct B { B(const A&); };
struct S {
A a;
B b;
};
int AcceptS(S s);
void Accept2(int x, int y);
void Test() {
Accept2(AcceptS({.a = A{}, .b = A{}}), ({ return; 0; }));
}We add cleanups as follows:
It is important to deactivate 5 using active flags. Without the active flags, the Patch is 62.57 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/89154.diff 11 Files Affected:
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 3f5463a9a70e9d..9004e96bc1a0cf 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4693,11 +4693,11 @@ void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
AggValueSlot Slot = args.isUsingInAlloca()
? createPlaceholderSlot(*this, type) : CreateAggTemp(type, "agg.tmp");
- bool DestroyedInCallee = true, NeedsEHCleanup = true;
+ bool DestroyedInCallee = true, NeedsCleanup = true;
if (const auto *RD = type->getAsCXXRecordDecl())
DestroyedInCallee = RD->hasNonTrivialDestructor();
else
- NeedsEHCleanup = needsEHCleanup(type.isDestructedType());
+ NeedsCleanup = type.isDestructedType();
if (DestroyedInCallee)
Slot.setExternallyDestructed();
@@ -4706,14 +4706,15 @@ void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
RValue RV = Slot.asRValue();
args.add(RV, type);
- if (DestroyedInCallee && NeedsEHCleanup) {
+ if (DestroyedInCallee && NeedsCleanup) {
// Create a no-op GEP between the placeholder and the cleanup so we can
// RAUW it successfully. It also serves as a marker of the first
// instruction where the cleanup is active.
- pushFullExprCleanup<DestroyUnpassedArg>(EHCleanup, Slot.getAddress(),
- type);
+ pushFullExprCleanup<DestroyUnpassedArg>(NormalAndEHCleanup,
+ Slot.getAddress(), type);
// This unreachable is a temporary marker which will be removed later.
- llvm::Instruction *IsActive = Builder.CreateUnreachable();
+ llvm::Instruction *IsActive =
+ Builder.CreateFlagLoad(llvm::Constant::getNullValue(Int8PtrTy));
args.addArgCleanupDeactivation(EHStack.stable_begin(), IsActive);
}
return;
diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index e6f8e6873004f2..469e0363b744ac 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -634,12 +634,19 @@ static void destroyOptimisticNormalEntry(CodeGenFunction &CGF,
/// Pops a cleanup block. If the block includes a normal cleanup, the
/// current insertion point is threaded through the cleanup, as are
/// any branch fixups on the cleanup.
-void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
+void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough,
+ bool ForDeactivation) {
assert(!EHStack.empty() && "cleanup stack is empty!");
assert(isa<EHCleanupScope>(*EHStack.begin()) && "top not a cleanup!");
EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin());
assert(Scope.getFixupDepth() <= EHStack.getNumBranchFixups());
+ // If we are deactivating a normal cleanup, we need to pretend that the
+ // fallthrough is unreachable. We restore this IP before returning.
+ CGBuilderTy::InsertPoint NormalDeactivateOrigIP;
+ if (ForDeactivation && (Scope.isNormalCleanup() || !getLangOpts().EHAsynch)) {
+ NormalDeactivateOrigIP = Builder.saveAndClearIP();
+ }
// Remember activation information.
bool IsActive = Scope.isActive();
Address NormalActiveFlag =
@@ -667,7 +674,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
// - whether there's a fallthrough
llvm::BasicBlock *FallthroughSource = Builder.GetInsertBlock();
- bool HasFallthrough = (FallthroughSource != nullptr && IsActive);
+ bool HasFallthrough =
+ FallthroughSource != nullptr && (IsActive || HasExistingBranches);
// Branch-through fall-throughs leave the insertion point set to the
// end of the last cleanup, which points to the current scope. The
@@ -692,7 +700,11 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
// If we have a prebranched fallthrough into an inactive normal
// cleanup, rewrite it so that it leads to the appropriate place.
- if (Scope.isNormalCleanup() && HasPrebranchedFallthrough && !IsActive) {
+ if (Scope.isNormalCleanup() && HasPrebranchedFallthrough &&
+ !RequiresNormalCleanup) {
+ // FIXME: Come up with a program which would need forwarding prebranched
+ // fallthrough and add tests. Otherwise delete this and assert against it.
+ assert(!IsActive);
llvm::BasicBlock *prebranchDest;
// If the prebranch is semantically branching through the next
@@ -724,6 +736,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
EHStack.popCleanup(); // safe because there are no fixups
assert(EHStack.getNumBranchFixups() == 0 ||
EHStack.hasNormalCleanups());
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
return;
}
@@ -760,11 +774,19 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
if (!RequiresNormalCleanup) {
// Mark CPP scope end for passed-by-value Arg temp
// per Windows ABI which is "normally" Cleanup in callee
- if (IsEHa && getInvokeDest() && Builder.GetInsertBlock()) {
- if (Personality.isMSVCXXPersonality())
+ if (IsEHa && getInvokeDest()) {
+ // If we are deactivating a normal cleanup then we don't have a
+ // fallthrough. Restore original IP to emit CPP scope ends in the correct
+ // block.
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
+ if (Personality.isMSVCXXPersonality() && Builder.GetInsertBlock())
EmitSehCppScopeEnd();
+ if (NormalDeactivateOrigIP.isSet())
+ NormalDeactivateOrigIP = Builder.saveAndClearIP();
}
destroyOptimisticNormalEntry(*this, Scope);
+ Scope.MarkEmitted();
EHStack.popCleanup();
} else {
// If we have a fallthrough and no other need for the cleanup,
@@ -781,6 +803,7 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
destroyOptimisticNormalEntry(*this, Scope);
+ Scope.MarkEmitted();
EHStack.popCleanup();
EmitCleanup(*this, Fn, cleanupFlags, NormalActiveFlag);
@@ -916,6 +939,7 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
// IV. Pop the cleanup and emit it.
+ Scope.MarkEmitted();
EHStack.popCleanup();
assert(EHStack.hasNormalCleanups() == HasEnclosingCleanups);
@@ -984,6 +1008,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
}
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
assert(EHStack.hasNormalCleanups() || EHStack.getNumBranchFixups() == 0);
// Emit the EH cleanup if required.
@@ -1143,25 +1169,6 @@ void CodeGenFunction::EmitBranchThroughCleanup(JumpDest Dest) {
Builder.ClearInsertionPoint();
}
-static bool IsUsedAsNormalCleanup(EHScopeStack &EHStack,
- EHScopeStack::stable_iterator C) {
- // If we needed a normal block for any reason, that counts.
- if (cast<EHCleanupScope>(*EHStack.find(C)).getNormalBlock())
- return true;
-
- // Check whether any enclosed cleanups were needed.
- for (EHScopeStack::stable_iterator
- I = EHStack.getInnermostNormalCleanup();
- I != C; ) {
- assert(C.strictlyEncloses(I));
- EHCleanupScope &S = cast<EHCleanupScope>(*EHStack.find(I));
- if (S.getNormalBlock()) return true;
- I = S.getEnclosingNormalCleanup();
- }
-
- return false;
-}
-
static bool IsUsedAsEHCleanup(EHScopeStack &EHStack,
EHScopeStack::stable_iterator cleanup) {
// If we needed an EH block for any reason, that counts.
@@ -1210,8 +1217,7 @@ static void SetupCleanupBlockActivation(CodeGenFunction &CGF,
// Calculate whether the cleanup was used:
// - as a normal cleanup
- if (Scope.isNormalCleanup() &&
- (isActivatedInConditional || IsUsedAsNormalCleanup(CGF.EHStack, C))) {
+ if (Scope.isNormalCleanup()) {
Scope.setTestFlagInNormalCleanup();
needFlag = true;
}
@@ -1224,13 +1230,16 @@ static void SetupCleanupBlockActivation(CodeGenFunction &CGF,
}
// If it hasn't yet been used as either, we're done.
- if (!needFlag) return;
+ if (!needFlag)
+ return;
Address var = Scope.getActiveFlag();
if (!var.isValid()) {
+ CodeGenFunction::AllocaTrackerRAII AllocaTracker(CGF);
var = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), CharUnits::One(),
"cleanup.isactive");
Scope.setActiveFlag(var);
+ Scope.AddAuxAllocas(AllocaTracker.Take());
assert(dominatingIP && "no existing variable and no dominating IP!");
@@ -1273,17 +1282,8 @@ void CodeGenFunction::DeactivateCleanupBlock(EHScopeStack::stable_iterator C,
// to the current RunCleanupsScope.
if (C == EHStack.stable_begin() &&
CurrentCleanupScopeDepth.strictlyEncloses(C)) {
- // Per comment below, checking EHAsynch is not really necessary
- // it's there to assure zero-impact w/o EHAsynch option
- if (!Scope.isNormalCleanup() && getLangOpts().EHAsynch) {
- PopCleanupBlock();
- } else {
- // If it's a normal cleanup, we need to pretend that the
- // fallthrough is unreachable.
- CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
- PopCleanupBlock();
- Builder.restoreIP(SavedIP);
- }
+ PopCleanupBlock(/*FallthroughIsBranchThrough=*/false,
+ /*ForDeactivation=*/true);
return;
}
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 03e4a29d7b3dbf..c73c97146abc4d 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -16,8 +16,11 @@
#include "EHScopeStack.h"
#include "Address.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/Instruction.h"
namespace llvm {
class BasicBlock;
@@ -266,6 +269,51 @@ class alignas(8) EHCleanupScope : public EHScope {
};
mutable struct ExtInfo *ExtInfo;
+ /// Erases auxillary allocas and their usages for an unused cleanup.
+ /// Cleanups should mark these allocas as 'used' if the cleanup is
+ /// emitted, otherwise these instructions would be erased.
+ struct AuxillaryAllocas {
+ SmallVector<llvm::Instruction *, 1> AuxAllocas;
+ bool used = false;
+
+ // Records a potentially unused instruction to be erased later.
+ void Add(llvm::AllocaInst *Alloca) { AuxAllocas.push_back(Alloca); }
+
+ // Mark all recorded instructions as used. These will not be erased later.
+ void MarkUsed() {
+ used = true;
+ AuxAllocas.clear();
+ }
+
+ ~AuxillaryAllocas() {
+ if (used)
+ return;
+ llvm::SetVector<llvm::Instruction *> Uses;
+ for (auto *Inst : llvm::reverse(AuxAllocas))
+ CollectUses(Inst, Uses);
+ // Delete uses in the reverse order of insertion.
+ for (auto *I : llvm::reverse(Uses))
+ I->eraseFromParent();
+ }
+
+ private:
+ void CollectUses(llvm::Instruction *I,
+ llvm::SetVector<llvm::Instruction *> &Uses) {
+ if (!I || !Uses.insert(I))
+ return;
+ for (auto *User : I->users())
+ CollectUses(cast<llvm::Instruction>(User), Uses);
+ }
+ };
+ mutable struct AuxillaryAllocas *AuxAllocas;
+
+ AuxillaryAllocas &getAuxillaryAllocas() {
+ if (!AuxAllocas) {
+ AuxAllocas = new struct AuxillaryAllocas();
+ }
+ return *AuxAllocas;
+ }
+
/// The number of fixups required by enclosing scopes (not including
/// this one). If this is the top cleanup scope, all the fixups
/// from this index onwards belong to this scope.
@@ -298,7 +346,7 @@ class alignas(8) EHCleanupScope : public EHScope {
EHScopeStack::stable_iterator enclosingEH)
: EHScope(EHScope::Cleanup, enclosingEH),
EnclosingNormal(enclosingNormal), NormalBlock(nullptr),
- ActiveFlag(Address::invalid()), ExtInfo(nullptr),
+ ActiveFlag(Address::invalid()), ExtInfo(nullptr), AuxAllocas(nullptr),
FixupDepth(fixupDepth) {
CleanupBits.IsNormalCleanup = isNormal;
CleanupBits.IsEHCleanup = isEH;
@@ -312,8 +360,15 @@ class alignas(8) EHCleanupScope : public EHScope {
}
void Destroy() {
+ if (AuxAllocas)
+ delete AuxAllocas;
delete ExtInfo;
}
+ void AddAuxAllocas(llvm::SmallVector<llvm::AllocaInst *> Allocas) {
+ for (auto *Alloca : Allocas)
+ getAuxillaryAllocas().Add(Alloca);
+ }
+ void MarkEmitted() { getAuxillaryAllocas().MarkUsed(); }
// Objects of EHCleanupScope are not destructed. Use Destroy().
~EHCleanupScope() = delete;
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index ce6d6d8956076e..3f05ebb561da57 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -19,6 +19,7 @@
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
+#include "EHScopeStack.h"
#include "PatternInit.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
@@ -2201,6 +2202,27 @@ void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, Address addr,
destroyer, useEHCleanupForArray);
}
+// Pushes a destroy and defers its deactivation until its
+// CleanupDeactivationScope is exited.
+void CodeGenFunction::pushDestroyAndDeferDeactivation(
+ QualType::DestructionKind dtorKind, Address addr, QualType type) {
+ assert(dtorKind && "cannot push destructor for trivial type");
+
+ CleanupKind cleanupKind = getCleanupKind(dtorKind);
+ pushDestroyAndDeferDeactivation(
+ cleanupKind, addr, type, getDestroyer(dtorKind), cleanupKind & EHCleanup);
+}
+
+void CodeGenFunction::pushDestroyAndDeferDeactivation(
+ CleanupKind cleanupKind, Address addr, QualType type, Destroyer *destroyer,
+ bool useEHCleanupForArray) {
+ llvm::Instruction *DominatingIP =
+ Builder.CreateFlagLoad(llvm::Constant::getNullValue(Int8PtrTy));
+ pushDestroy(cleanupKind, addr, type, destroyer, useEHCleanupForArray);
+ DeferredDeactivationCleanupStack.push_back(
+ {EHStack.stable_begin(), DominatingIP});
+}
+
void CodeGenFunction::pushStackRestore(CleanupKind Kind, Address SPMem) {
EHStack.pushCleanup<CallStackRestore>(Kind, SPMem);
}
@@ -2217,16 +2239,19 @@ void CodeGenFunction::pushLifetimeExtendedDestroy(CleanupKind cleanupKind,
// If we're not in a conditional branch, we don't need to bother generating a
// conditional cleanup.
if (!isInConditionalBranch()) {
- // Push an EH-only cleanup for the object now.
// FIXME: When popping normal cleanups, we need to keep this EH cleanup
// around in case a temporary's destructor throws an exception.
- if (cleanupKind & EHCleanup)
- EHStack.pushCleanup<DestroyObject>(
- static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
- destroyer, useEHCleanupForArray);
+ // Add the cleanup to the EHStack. After the full-expr, this would be
+ // deactivated before being popped from the stack.
+ pushDestroyAndDeferDeactivation(cleanupKind, addr, type, destroyer,
+ useEHCleanupForArray);
+
+ // Since this is lifetime-extended, push it once again to the EHStack after
+ // the full expression.
return pushCleanupAfterFullExprWithActiveFlag<DestroyObject>(
- cleanupKind, Address::invalid(), addr, type, destroyer, useEHCleanupForArray);
+ cleanupKind, Address::invalid(), addr, type, destroyer,
+ useEHCleanupForArray);
}
// Otherwise, we should only destroy the object if it's been initialized.
@@ -2241,13 +2266,12 @@ void CodeGenFunction::pushLifetimeExtendedDestroy(CleanupKind cleanupKind,
Address ActiveFlag = createCleanupActiveFlag();
SavedType SavedAddr = saveValueInCond(addr);
- if (cleanupKind & EHCleanup) {
- EHStack.pushCleanup<ConditionalCleanupType>(
- static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), SavedAddr, type,
- destroyer, useEHCleanupForArray);
- initFullExprCleanupWithFlag(ActiveFlag);
- }
+ pushCleanupAndDeferDeactivation<ConditionalCleanupType>(
+ cleanupKind, SavedAddr, type, destroyer, useEHCleanupForArray);
+ initFullExprCleanupWithFlag(ActiveFlag);
+ // Since this is lifetime-extended, push it once again to the EHStack after
+ // the full expression.
pushCleanupAfterFullExprWithActiveFlag<ConditionalCleanupType>(
cleanupKind, ActiveFlag, SavedAddr, type, destroyer,
useEHCleanupForArray);
@@ -2442,9 +2466,9 @@ namespace {
};
} // end anonymous namespace
-/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
-/// already-constructed elements of the given array. The cleanup
-/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
+/// pushIrregularPartialArrayCleanup - Push a NormalAndEHCleanup to
+/// destroy already-constructed elements of the given array. The cleanup may be
+/// popped with DeactivateCleanupBlock or PopCleanupBlock.
///
/// \param elementType - the immediate element type of the array;
/// possibly still an array type
@@ -2453,10 +2477,9 @@ void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
QualType elementType,
CharUnits elementAlign,
Destroyer *destroyer) {
- pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
- arrayBegin, arrayEndPointer,
- elementType, elementAlign,
- destroyer);
+ pushFullExprCleanup<IrregularPartialArrayDestroy>(
+ NormalAndEHCleanup, arrayBegin, arrayEndPointer, elementType,
+ elementAlign, destroyer);
}
/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index cf696a1c9f560f..c85a339f5e3f88 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -115,10 +115,16 @@ RawAddress CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name,
llvm::Value *ArraySize) {
+ llvm::AllocaInst *Alloca;
if (ArraySize)
- return Builder.CreateAlloca(Ty, ArraySize, Name);
- return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
- ArraySize, Name, AllocaInsertPt);
+ Alloca = Builder.CreateAlloca(Ty, ArraySize, Name);
+ else
+ Alloca = new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
+ ArraySize, Name, AllocaInsertPt);
+ if (Allocas) {
+ Allocas->Add(Alloca);
+ }
+ return Alloca;
}
/// CreateDefaultAlignTempAlloca - This creates an alloca with the
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 1b9287ea239347..560a9e2c5ead5c 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -15,6 +15,7 @@
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
+#include "EHScopeStack.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
@@ -24,6 +25,7 @@
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
using namespace clang;
@@ -558,24 +560,27 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
// For that, we'll need an EH cleanup.
QualType::DestructionKind dtorKind = elementType.isDestructedType();
Address endOfInit = Address::invalid();
- EHScopeStack::stable_iterator cleanup;
- llvm::Instruction *cleanupDominator = nullptr;
- if (CGF.needsEHCleanup(dtorKind)) {
+ CodeGenFunction::CleanupDeactivationScope deactivation(CGF);
+
+ if (dtorKind) {
+ CodeGenFunction::AllocaTrackerRAII allocaTracker(CGF);
// In principle we could tell the cleanup where...
[truncated]
|
|
@llvm/pr-subscribers-coroutines Author: Utkarsh Saxena (usx95) ChangesLatest diff: https://github.com/llvm/llvm-project/pull/89154/files/f1ab4c2677394bbfc985d9680d5eecd7b2e6a882..26bb3b19c551348de5bf88bd16f90b60c28a8a2b struct A { };
struct B { B(const A&); };
struct S {
A a;
B b;
};
int AcceptS(S s);
void Accept2(int x, int y);
void Test() {
Accept2(AcceptS({.a = A{}, .b = A{}}), ({ return; 0; }));
}We add cleanups as follows:
It is important to deactivate 5 using active flags. Without the active flags, the Patch is 62.57 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/89154.diff 11 Files Affected:
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 3f5463a9a70e9d..9004e96bc1a0cf 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4693,11 +4693,11 @@ void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
AggValueSlot Slot = args.isUsingInAlloca()
? createPlaceholderSlot(*this, type) : CreateAggTemp(type, "agg.tmp");
- bool DestroyedInCallee = true, NeedsEHCleanup = true;
+ bool DestroyedInCallee = true, NeedsCleanup = true;
if (const auto *RD = type->getAsCXXRecordDecl())
DestroyedInCallee = RD->hasNonTrivialDestructor();
else
- NeedsEHCleanup = needsEHCleanup(type.isDestructedType());
+ NeedsCleanup = type.isDestructedType();
if (DestroyedInCallee)
Slot.setExternallyDestructed();
@@ -4706,14 +4706,15 @@ void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
RValue RV = Slot.asRValue();
args.add(RV, type);
- if (DestroyedInCallee && NeedsEHCleanup) {
+ if (DestroyedInCallee && NeedsCleanup) {
// Create a no-op GEP between the placeholder and the cleanup so we can
// RAUW it successfully. It also serves as a marker of the first
// instruction where the cleanup is active.
- pushFullExprCleanup<DestroyUnpassedArg>(EHCleanup, Slot.getAddress(),
- type);
+ pushFullExprCleanup<DestroyUnpassedArg>(NormalAndEHCleanup,
+ Slot.getAddress(), type);
// This unreachable is a temporary marker which will be removed later.
- llvm::Instruction *IsActive = Builder.CreateUnreachable();
+ llvm::Instruction *IsActive =
+ Builder.CreateFlagLoad(llvm::Constant::getNullValue(Int8PtrTy));
args.addArgCleanupDeactivation(EHStack.stable_begin(), IsActive);
}
return;
diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index e6f8e6873004f2..469e0363b744ac 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -634,12 +634,19 @@ static void destroyOptimisticNormalEntry(CodeGenFunction &CGF,
/// Pops a cleanup block. If the block includes a normal cleanup, the
/// current insertion point is threaded through the cleanup, as are
/// any branch fixups on the cleanup.
-void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
+void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough,
+ bool ForDeactivation) {
assert(!EHStack.empty() && "cleanup stack is empty!");
assert(isa<EHCleanupScope>(*EHStack.begin()) && "top not a cleanup!");
EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin());
assert(Scope.getFixupDepth() <= EHStack.getNumBranchFixups());
+ // If we are deactivating a normal cleanup, we need to pretend that the
+ // fallthrough is unreachable. We restore this IP before returning.
+ CGBuilderTy::InsertPoint NormalDeactivateOrigIP;
+ if (ForDeactivation && (Scope.isNormalCleanup() || !getLangOpts().EHAsynch)) {
+ NormalDeactivateOrigIP = Builder.saveAndClearIP();
+ }
// Remember activation information.
bool IsActive = Scope.isActive();
Address NormalActiveFlag =
@@ -667,7 +674,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
// - whether there's a fallthrough
llvm::BasicBlock *FallthroughSource = Builder.GetInsertBlock();
- bool HasFallthrough = (FallthroughSource != nullptr && IsActive);
+ bool HasFallthrough =
+ FallthroughSource != nullptr && (IsActive || HasExistingBranches);
// Branch-through fall-throughs leave the insertion point set to the
// end of the last cleanup, which points to the current scope. The
@@ -692,7 +700,11 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
// If we have a prebranched fallthrough into an inactive normal
// cleanup, rewrite it so that it leads to the appropriate place.
- if (Scope.isNormalCleanup() && HasPrebranchedFallthrough && !IsActive) {
+ if (Scope.isNormalCleanup() && HasPrebranchedFallthrough &&
+ !RequiresNormalCleanup) {
+ // FIXME: Come up with a program which would need forwarding prebranched
+ // fallthrough and add tests. Otherwise delete this and assert against it.
+ assert(!IsActive);
llvm::BasicBlock *prebranchDest;
// If the prebranch is semantically branching through the next
@@ -724,6 +736,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
EHStack.popCleanup(); // safe because there are no fixups
assert(EHStack.getNumBranchFixups() == 0 ||
EHStack.hasNormalCleanups());
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
return;
}
@@ -760,11 +774,19 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
if (!RequiresNormalCleanup) {
// Mark CPP scope end for passed-by-value Arg temp
// per Windows ABI which is "normally" Cleanup in callee
- if (IsEHa && getInvokeDest() && Builder.GetInsertBlock()) {
- if (Personality.isMSVCXXPersonality())
+ if (IsEHa && getInvokeDest()) {
+ // If we are deactivating a normal cleanup then we don't have a
+ // fallthrough. Restore original IP to emit CPP scope ends in the correct
+ // block.
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
+ if (Personality.isMSVCXXPersonality() && Builder.GetInsertBlock())
EmitSehCppScopeEnd();
+ if (NormalDeactivateOrigIP.isSet())
+ NormalDeactivateOrigIP = Builder.saveAndClearIP();
}
destroyOptimisticNormalEntry(*this, Scope);
+ Scope.MarkEmitted();
EHStack.popCleanup();
} else {
// If we have a fallthrough and no other need for the cleanup,
@@ -781,6 +803,7 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
destroyOptimisticNormalEntry(*this, Scope);
+ Scope.MarkEmitted();
EHStack.popCleanup();
EmitCleanup(*this, Fn, cleanupFlags, NormalActiveFlag);
@@ -916,6 +939,7 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
// IV. Pop the cleanup and emit it.
+ Scope.MarkEmitted();
EHStack.popCleanup();
assert(EHStack.hasNormalCleanups() == HasEnclosingCleanups);
@@ -984,6 +1008,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
}
}
+ if (NormalDeactivateOrigIP.isSet())
+ Builder.restoreIP(NormalDeactivateOrigIP);
assert(EHStack.hasNormalCleanups() || EHStack.getNumBranchFixups() == 0);
// Emit the EH cleanup if required.
@@ -1143,25 +1169,6 @@ void CodeGenFunction::EmitBranchThroughCleanup(JumpDest Dest) {
Builder.ClearInsertionPoint();
}
-static bool IsUsedAsNormalCleanup(EHScopeStack &EHStack,
- EHScopeStack::stable_iterator C) {
- // If we needed a normal block for any reason, that counts.
- if (cast<EHCleanupScope>(*EHStack.find(C)).getNormalBlock())
- return true;
-
- // Check whether any enclosed cleanups were needed.
- for (EHScopeStack::stable_iterator
- I = EHStack.getInnermostNormalCleanup();
- I != C; ) {
- assert(C.strictlyEncloses(I));
- EHCleanupScope &S = cast<EHCleanupScope>(*EHStack.find(I));
- if (S.getNormalBlock()) return true;
- I = S.getEnclosingNormalCleanup();
- }
-
- return false;
-}
-
static bool IsUsedAsEHCleanup(EHScopeStack &EHStack,
EHScopeStack::stable_iterator cleanup) {
// If we needed an EH block for any reason, that counts.
@@ -1210,8 +1217,7 @@ static void SetupCleanupBlockActivation(CodeGenFunction &CGF,
// Calculate whether the cleanup was used:
// - as a normal cleanup
- if (Scope.isNormalCleanup() &&
- (isActivatedInConditional || IsUsedAsNormalCleanup(CGF.EHStack, C))) {
+ if (Scope.isNormalCleanup()) {
Scope.setTestFlagInNormalCleanup();
needFlag = true;
}
@@ -1224,13 +1230,16 @@ static void SetupCleanupBlockActivation(CodeGenFunction &CGF,
}
// If it hasn't yet been used as either, we're done.
- if (!needFlag) return;
+ if (!needFlag)
+ return;
Address var = Scope.getActiveFlag();
if (!var.isValid()) {
+ CodeGenFunction::AllocaTrackerRAII AllocaTracker(CGF);
var = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), CharUnits::One(),
"cleanup.isactive");
Scope.setActiveFlag(var);
+ Scope.AddAuxAllocas(AllocaTracker.Take());
assert(dominatingIP && "no existing variable and no dominating IP!");
@@ -1273,17 +1282,8 @@ void CodeGenFunction::DeactivateCleanupBlock(EHScopeStack::stable_iterator C,
// to the current RunCleanupsScope.
if (C == EHStack.stable_begin() &&
CurrentCleanupScopeDepth.strictlyEncloses(C)) {
- // Per comment below, checking EHAsynch is not really necessary
- // it's there to assure zero-impact w/o EHAsynch option
- if (!Scope.isNormalCleanup() && getLangOpts().EHAsynch) {
- PopCleanupBlock();
- } else {
- // If it's a normal cleanup, we need to pretend that the
- // fallthrough is unreachable.
- CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
- PopCleanupBlock();
- Builder.restoreIP(SavedIP);
- }
+ PopCleanupBlock(/*FallthroughIsBranchThrough=*/false,
+ /*ForDeactivation=*/true);
return;
}
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 03e4a29d7b3dbf..c73c97146abc4d 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -16,8 +16,11 @@
#include "EHScopeStack.h"
#include "Address.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/Instruction.h"
namespace llvm {
class BasicBlock;
@@ -266,6 +269,51 @@ class alignas(8) EHCleanupScope : public EHScope {
};
mutable struct ExtInfo *ExtInfo;
+ /// Erases auxillary allocas and their usages for an unused cleanup.
+ /// Cleanups should mark these allocas as 'used' if the cleanup is
+ /// emitted, otherwise these instructions would be erased.
+ struct AuxillaryAllocas {
+ SmallVector<llvm::Instruction *, 1> AuxAllocas;
+ bool used = false;
+
+ // Records a potentially unused instruction to be erased later.
+ void Add(llvm::AllocaInst *Alloca) { AuxAllocas.push_back(Alloca); }
+
+ // Mark all recorded instructions as used. These will not be erased later.
+ void MarkUsed() {
+ used = true;
+ AuxAllocas.clear();
+ }
+
+ ~AuxillaryAllocas() {
+ if (used)
+ return;
+ llvm::SetVector<llvm::Instruction *> Uses;
+ for (auto *Inst : llvm::reverse(AuxAllocas))
+ CollectUses(Inst, Uses);
+ // Delete uses in the reverse order of insertion.
+ for (auto *I : llvm::reverse(Uses))
+ I->eraseFromParent();
+ }
+
+ private:
+ void CollectUses(llvm::Instruction *I,
+ llvm::SetVector<llvm::Instruction *> &Uses) {
+ if (!I || !Uses.insert(I))
+ return;
+ for (auto *User : I->users())
+ CollectUses(cast<llvm::Instruction>(User), Uses);
+ }
+ };
+ mutable struct AuxillaryAllocas *AuxAllocas;
+
+ AuxillaryAllocas &getAuxillaryAllocas() {
+ if (!AuxAllocas) {
+ AuxAllocas = new struct AuxillaryAllocas();
+ }
+ return *AuxAllocas;
+ }
+
/// The number of fixups required by enclosing scopes (not including
/// this one). If this is the top cleanup scope, all the fixups
/// from this index onwards belong to this scope.
@@ -298,7 +346,7 @@ class alignas(8) EHCleanupScope : public EHScope {
EHScopeStack::stable_iterator enclosingEH)
: EHScope(EHScope::Cleanup, enclosingEH),
EnclosingNormal(enclosingNormal), NormalBlock(nullptr),
- ActiveFlag(Address::invalid()), ExtInfo(nullptr),
+ ActiveFlag(Address::invalid()), ExtInfo(nullptr), AuxAllocas(nullptr),
FixupDepth(fixupDepth) {
CleanupBits.IsNormalCleanup = isNormal;
CleanupBits.IsEHCleanup = isEH;
@@ -312,8 +360,15 @@ class alignas(8) EHCleanupScope : public EHScope {
}
void Destroy() {
+ if (AuxAllocas)
+ delete AuxAllocas;
delete ExtInfo;
}
+ void AddAuxAllocas(llvm::SmallVector<llvm::AllocaInst *> Allocas) {
+ for (auto *Alloca : Allocas)
+ getAuxillaryAllocas().Add(Alloca);
+ }
+ void MarkEmitted() { getAuxillaryAllocas().MarkUsed(); }
// Objects of EHCleanupScope are not destructed. Use Destroy().
~EHCleanupScope() = delete;
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index ce6d6d8956076e..3f05ebb561da57 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -19,6 +19,7 @@
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
+#include "EHScopeStack.h"
#include "PatternInit.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
@@ -2201,6 +2202,27 @@ void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, Address addr,
destroyer, useEHCleanupForArray);
}
+// Pushes a destroy and defers its deactivation until its
+// CleanupDeactivationScope is exited.
+void CodeGenFunction::pushDestroyAndDeferDeactivation(
+ QualType::DestructionKind dtorKind, Address addr, QualType type) {
+ assert(dtorKind && "cannot push destructor for trivial type");
+
+ CleanupKind cleanupKind = getCleanupKind(dtorKind);
+ pushDestroyAndDeferDeactivation(
+ cleanupKind, addr, type, getDestroyer(dtorKind), cleanupKind & EHCleanup);
+}
+
+void CodeGenFunction::pushDestroyAndDeferDeactivation(
+ CleanupKind cleanupKind, Address addr, QualType type, Destroyer *destroyer,
+ bool useEHCleanupForArray) {
+ llvm::Instruction *DominatingIP =
+ Builder.CreateFlagLoad(llvm::Constant::getNullValue(Int8PtrTy));
+ pushDestroy(cleanupKind, addr, type, destroyer, useEHCleanupForArray);
+ DeferredDeactivationCleanupStack.push_back(
+ {EHStack.stable_begin(), DominatingIP});
+}
+
void CodeGenFunction::pushStackRestore(CleanupKind Kind, Address SPMem) {
EHStack.pushCleanup<CallStackRestore>(Kind, SPMem);
}
@@ -2217,16 +2239,19 @@ void CodeGenFunction::pushLifetimeExtendedDestroy(CleanupKind cleanupKind,
// If we're not in a conditional branch, we don't need to bother generating a
// conditional cleanup.
if (!isInConditionalBranch()) {
- // Push an EH-only cleanup for the object now.
// FIXME: When popping normal cleanups, we need to keep this EH cleanup
// around in case a temporary's destructor throws an exception.
- if (cleanupKind & EHCleanup)
- EHStack.pushCleanup<DestroyObject>(
- static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
- destroyer, useEHCleanupForArray);
+ // Add the cleanup to the EHStack. After the full-expr, this would be
+ // deactivated before being popped from the stack.
+ pushDestroyAndDeferDeactivation(cleanupKind, addr, type, destroyer,
+ useEHCleanupForArray);
+
+ // Since this is lifetime-extended, push it once again to the EHStack after
+ // the full expression.
return pushCleanupAfterFullExprWithActiveFlag<DestroyObject>(
- cleanupKind, Address::invalid(), addr, type, destroyer, useEHCleanupForArray);
+ cleanupKind, Address::invalid(), addr, type, destroyer,
+ useEHCleanupForArray);
}
// Otherwise, we should only destroy the object if it's been initialized.
@@ -2241,13 +2266,12 @@ void CodeGenFunction::pushLifetimeExtendedDestroy(CleanupKind cleanupKind,
Address ActiveFlag = createCleanupActiveFlag();
SavedType SavedAddr = saveValueInCond(addr);
- if (cleanupKind & EHCleanup) {
- EHStack.pushCleanup<ConditionalCleanupType>(
- static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), SavedAddr, type,
- destroyer, useEHCleanupForArray);
- initFullExprCleanupWithFlag(ActiveFlag);
- }
+ pushCleanupAndDeferDeactivation<ConditionalCleanupType>(
+ cleanupKind, SavedAddr, type, destroyer, useEHCleanupForArray);
+ initFullExprCleanupWithFlag(ActiveFlag);
+ // Since this is lifetime-extended, push it once again to the EHStack after
+ // the full expression.
pushCleanupAfterFullExprWithActiveFlag<ConditionalCleanupType>(
cleanupKind, ActiveFlag, SavedAddr, type, destroyer,
useEHCleanupForArray);
@@ -2442,9 +2466,9 @@ namespace {
};
} // end anonymous namespace
-/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
-/// already-constructed elements of the given array. The cleanup
-/// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
+/// pushIrregularPartialArrayCleanup - Push a NormalAndEHCleanup to
+/// destroy already-constructed elements of the given array. The cleanup may be
+/// popped with DeactivateCleanupBlock or PopCleanupBlock.
///
/// \param elementType - the immediate element type of the array;
/// possibly still an array type
@@ -2453,10 +2477,9 @@ void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
QualType elementType,
CharUnits elementAlign,
Destroyer *destroyer) {
- pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
- arrayBegin, arrayEndPointer,
- elementType, elementAlign,
- destroyer);
+ pushFullExprCleanup<IrregularPartialArrayDestroy>(
+ NormalAndEHCleanup, arrayBegin, arrayEndPointer, elementType,
+ elementAlign, destroyer);
}
/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index cf696a1c9f560f..c85a339f5e3f88 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -115,10 +115,16 @@ RawAddress CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name,
llvm::Value *ArraySize) {
+ llvm::AllocaInst *Alloca;
if (ArraySize)
- return Builder.CreateAlloca(Ty, ArraySize, Name);
- return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
- ArraySize, Name, AllocaInsertPt);
+ Alloca = Builder.CreateAlloca(Ty, ArraySize, Name);
+ else
+ Alloca = new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
+ ArraySize, Name, AllocaInsertPt);
+ if (Allocas) {
+ Allocas->Add(Alloca);
+ }
+ return Alloca;
}
/// CreateDefaultAlignTempAlloca - This creates an alloca with the
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 1b9287ea239347..560a9e2c5ead5c 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -15,6 +15,7 @@
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
+#include "EHScopeStack.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
@@ -24,6 +25,7 @@
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
using namespace clang;
@@ -558,24 +560,27 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
// For that, we'll need an EH cleanup.
QualType::DestructionKind dtorKind = elementType.isDestructedType();
Address endOfInit = Address::invalid();
- EHScopeStack::stable_iterator cleanup;
- llvm::Instruction *cleanupDominator = nullptr;
- if (CGF.needsEHCleanup(dtorKind)) {
+ CodeGenFunction::CleanupDeactivationScope deactivation(CGF);
+
+ if (dtorKind) {
+ CodeGenFunction::AllocaTrackerRAII allocaTracker(CGF);
// In principle we could tell the cleanup where...
[truncated]
|
|
What, if anything, about the scenario you're describing is specific to "normal" cleanups? |
|
(addressed one more problem with conditional lifetime extension.)
We do not see this with |
|
@efriedma-quic Ping. Does that make sense ? |
|
@efriedma-quic Ping! |
|
I have built a very large corpus with a clang built with these changes and ran its tests. No compilation or test failures were reported. The corpus was built with exceptions disabled. That said, a breakage with missing destructors or double-free can likely be associated with this patch. Please report any breakages, especially with exceptions enabled. |
|
This seems to have fixed #60112. Thanks! |
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Latest diff: https://github.com/llvm/llvm-project/pull/89154/files/f1ab4c2677394bbfc985d9680d5eecd7b2e6a882..adf9bc902baddb156c83ce0f8ec03c142e806d45
We address two additional bugs here:
Problem 1: Deactivated normal cleanup still runs, leading to double-free
Consider the following:
We add cleanups as follows:
S::aA{}(used byB(const A&)in.b = A{})S::bS::b-> This pops the cleanup.S::a-> Does not pop the cleanup as 2 is top. Should create active flag!!~S().It is important to deactivate 5 using active flags. Without the active flags, the
returnwill fallthrough it and would run both~S()and dtorS::aleading to double free of~A().In this patch, we unconditionally emit active flags while deactivating normal cleanups. These flags are deleted later by the
AllocaTrackerif the cleanup is not emitted.Problem 2: Missing cleanup for conditional lifetime extension
We push 2 cleanups for lifetime-extended cleanup. The first cleanup is useful if we exit from the middle of the expression (stmt-expr/coro suspensions). This is deactivated after full-expr, and a new cleanup is pushed, extending the lifetime of the temporaries (to the scope of the reference being initialized).
If this lifetime extension happens to be conditional, then we use active flags to remember whether the branch was taken and if the object was initialized.
Previously, we used a single active flag, which was used by both cleanups. This is wrong because the first cleanup will be forced to deactivate after the full-expr and therefore this active flag will always be inactive. The dtor for the lifetime extended entity would not run as it always sees an inactive flag.
In this patch, we solve this using two separate active flags for both cleanups. Both of them are activated if the conditional branch is taken, but only one of them is deactivated after the full-expr.
Fixes #63818
Fixes #88478
Previous PR logs: