jdoerfert updated this revision to Diff 229448.
jdoerfert marked 5 inline comments as done.
jdoerfert added a comment.
Addressed comments
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D70258/new/
https://reviews.llvm.org/D70258
Files:
clang/lib/CodeGen/CGOpenMPRuntime.cpp
llvm/include/llvm/Frontend/OpenMPIRBuilder.h
llvm/lib/Frontend/OpenMPIRBuilder.cpp
Index: llvm/lib/Frontend/OpenMPIRBuilder.cpp
===================================================================
--- llvm/lib/Frontend/OpenMPIRBuilder.cpp
+++ llvm/lib/Frontend/OpenMPIRBuilder.cpp
@@ -228,7 +228,8 @@
// If we are in a cancellable parallel region, barriers are cancellation
// points.
// TODO: Check why we would force simple calls or to ignore the cancel flag.
- bool UseCancelBarrier = !ForceSimpleCall && CancellationBlock;
+ bool UseCancelBarrier =
+ !ForceSimpleCall && isLastFinalizationInfoCancellable(OMPD_parallel);
Value *Result = Builder.CreateCall(
getOrCreateRuntimeFunction(UseCancelBarrier ? OMPRTL___kmpc_cancel_barrier
@@ -248,13 +249,14 @@
Builder.CreateCondBr(Cmp, NonCancellationBlock, CancellationBlock,
/* TODO weight */ nullptr, nullptr);
- Builder.SetInsertPoint(NonCancellationBlock);
- assert(CancellationBlock->getParent() == BB->getParent() &&
- "Unexpected cancellation block parent!");
+ // From the cancellation block we finalize all variables and go to the
+ // post finalization block that is known to the FiniCB callback.
+ Builder.SetInsertPoint(CancellationBlock);
+ auto &FI = FinalizationStack.back();
+ FI.FiniCB(Builder.saveIP());
- // TODO: This is a workaround for now, we always reset the cancellation
- // block until we manage it ourselves here.
- CancellationBlock = nullptr;
+ // The continuation block is where code generation continues.
+ Builder.SetInsertPoint(NonCancellationBlock);
}
return Builder.saveIP();
Index: llvm/include/llvm/Frontend/OpenMPIRBuilder.h
===================================================================
--- llvm/include/llvm/Frontend/OpenMPIRBuilder.h
+++ llvm/include/llvm/Frontend/OpenMPIRBuilder.h
@@ -37,12 +37,44 @@
/// Add attributes known for \p FnID to \p Fn.
void addAttributes(omp::RuntimeFunction FnID, Function &Fn);
- /// Set the cancellation block to \p CBB.
- void setCancellationBlock(BasicBlock *CBB) { CancellationBlock = CBB; }
-
/// Type used throughout for insertion points.
using InsertPointTy = IRBuilder<>::InsertPoint;
+ /// Callback type for variable finalization (think destructors).
+ ///
+ /// \param CodeGenIP is the insertion point at which the finalization code
+ /// should be placed.
+ ///
+ /// A finalize callback knows about all objects that need finalization, e.g.
+ /// destruction, when the scope of the currently generated construct is left
+ /// at the time, and location, the callback is invoked.
+ using FinalizeCallbackTy = function_ref<void(InsertPointTy /* CodeGenIP */)>;
+
+ struct FinalizationInfo {
+ /// The finalization callback provided by the last in-flight invocation of
+ /// CreateXXXX for the directive of kind DK.
+ FinalizeCallbackTy FiniCB;
+
+ /// The directive kind of the innermost directive that has an associated
+ /// region which might require finalization when it is left.
+ omp::Directive DK;
+
+ /// Flag to indicate if the directive is cancellable.
+ bool IsCancellable;
+ };
+
+ /// Push a finalization callback on the finalization stack.
+ ///
+ /// NOTE: Temporary solution until Clang CG is gone.
+ void pushFinalizationCB(FinalizationInfo &&FI) {
+ FinalizationStack.emplace_back(std::move(FI));
+ }
+
+ /// Pop the last finalization callback from the finalization stack.
+ ///
+ /// NOTE: Temporary solution until Clang CG is gone.
+ void popFinalizationCB() { FinalizationStack.pop_back(); }
+
/// Description of a LLVM-IR insertion point (IP) and a debug/source location
/// (filename, line, column, ...).
struct LocationDescription {
@@ -112,6 +144,19 @@
omp::Directive DK, bool ForceSimpleCall,
bool CheckCancelFlag);
+ /// The finalization stack made up of finalize callbacks currently in-flight,
+ /// wrapped into FinalizationInfo objects that reference also the finalization
+ /// target block and the kind of cancellable directive.
+ SmallVector<FinalizationInfo, 8> FinalizationStack;
+
+ /// Return true if the last entry in the finalization stack is of kind \p DK
+ /// and cancellable.
+ bool isLastFinalizationInfoCancellable(omp::Directive DK) {
+ return !FinalizationStack.empty() &&
+ FinalizationStack.back().IsCancellable &&
+ FinalizationStack.back().DK == DK;
+ }
+
/// Return the current thread ID.
///
/// \param Ident The ident (ident_t*) describing the query origin.
@@ -123,9 +168,6 @@
/// The LLVM-IR Builder used to create IR.
IRBuilder<> Builder;
- /// TODO: Stub for a cancellation block stack.
- BasicBlock *CancellationBlock = nullptr;
-
/// Map to remember the thread in a function.
DenseMap<Function *, Value *> ThreadIDMap;
Index: clang/lib/CodeGen/CGOpenMPRuntime.cpp
===================================================================
--- clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -1462,10 +1462,50 @@
else if (const auto *OPFD =
dyn_cast<OMPTargetTeamsDistributeParallelForDirective>(&D))
HasCancel = OPFD->hasCancel();
+
+ // TODO: Temporarily inform the OpenMPIRBuilder, if any, about the new
+ // parallel region to make cancellation barriers work properly.
+ llvm::OpenMPIRBuilder *OMPBuilder = CGM.getOpenMPIRBuilder();
+ if (OMPBuilder) {
+
+ // The following callback is the crucial part of clangs cleanup process.
+ //
+ // NOTE:
+ // Once the OpenMPIRBuilder is used to create parallel regions (and
+ // similar), the cancellation destination (Dest below) is determined via
+ // IP. That means if we have variables to finalize we split the block at IP,
+ // use the new block (=BB) as destination to build a JumpDest (via
+ // getJumpDestInCurrentScope(BB)) which then is fed to
+ // EmitBranchThroughCleanup. Furhtermore, there will not be the need
+ // to push & pop an FinalizationInfo object.
+ // The FiniCB will still be needed otherwise but at the point where the
+ // OpenMPIRBuilder is asked to construct a parallel (or similar) construct.
+ auto FiniCB = [&CGF](llvm::OpenMPIRBuilder::InsertPointTy IP) {
+ assert(IP.getBlock()->end() == IP.getPoint() &&
+ "Clang CG should cause non-terminated block!");
+ CGBuilderTy::InsertPointGuard IPG(CGF.Builder);
+ CodeGenFunction::JumpDest Dest =
+ CGF.getOMPCancelDestination(OMPD_parallel);
+ CGF.EmitBranchThroughCleanup(Dest);
+ };
+
+ // TODO: Remove this once we emit parallel regions through the
+ // OpenMPIRBuilder as it can do this setup internally.
+ llvm::OpenMPIRBuilder::FinalizationInfo FI(
+ {FiniCB, OMPD_parallel, HasCancel});
+ OMPBuilder->pushFinalizationCB(std::move(FI));
+ }
+
CGOpenMPOutlinedRegionInfo CGInfo(*CS, ThreadIDVar, CodeGen, InnermostKind,
HasCancel, OutlinedHelperName);
CodeGenFunction::CGCapturedStmtRAII CapInfoRAII(CGF, &CGInfo);
- return CGF.GenerateOpenMPCapturedStmtFunction(*CS);
+ llvm::Function *Fn = CGF.GenerateOpenMPCapturedStmtFunction(*CS);
+
+ // TODO: See the TODOs above.
+ if (OMPBuilder)
+ OMPBuilder->popFinalizationCB();
+
+ return Fn;
}
llvm::Function *CGOpenMPRuntime::emitParallelOutlinedFunction(
@@ -3483,21 +3523,8 @@
dyn_cast_or_null<CGOpenMPRegionInfo>(CGF.CapturedStmtInfo);
llvm::OpenMPIRBuilder *OMPBuilder = CGF.CGM.getOpenMPIRBuilder();
if (OMPBuilder) {
- // TODO: Move cancelation point handling into the IRBuilder.
- if (EmitChecks && !ForceSimpleCall && OMPRegionInfo &&
- OMPRegionInfo->hasCancel()) {
- CGBuilderTy::InsertPointGuard IPG(CGF.Builder);
- llvm::BasicBlock *ExitBB =
- CGF.createBasicBlock(".cancel.exit", IP.getBlock()->getParent());
- OMPBuilder->setCancellationBlock(ExitBB);
- CGF.Builder.SetInsertPoint(ExitBB);
- CodeGenFunction::JumpDest CancelDestination =
- CGF.getOMPCancelDestination(OMPRegionInfo->getDirectiveKind());
- CGF.EmitBranchThroughCleanup(CancelDestination);
- }
- auto IP = OMPBuilder->CreateBarrier(CGF.Builder, Kind, ForceSimpleCall,
- EmitChecks);
- CGF.Builder.restoreIP(IP);
+ CGF.Builder.restoreIP(OMPBuilder->CreateBarrier(
+ CGF.Builder, Kind, ForceSimpleCall, EmitChecks));
return;
}
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