Commit dd822f5b authored by Alexey Bataev's avatar Alexey Bataev
Browse files

Merging r287227: 

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r287227 | abataev | 2016-11-17 15:12:05 +0000 (Thu, 17 Nov 2016) | 4 lines

[OPENMP] Fixed codegen for 'omp cancel' construct.

If 'omp cancel' construct is used in a worksharing construct it may
cause hanging of the software in case if reduction clause is used. Patch fixes this problem by avoiding extra reduction processing for branches that were canceled.
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llvm-svn: 288048
parent 88f283a1

clang/lib/CodeGen/CGStmtOpenMP.cpp

+19 −31
Original line number Diff line number Diff line
@@ -1767,17 +1767,11 @@ void CodeGenFunction::EmitOMPOuterLoop(bool DynamicOrOrdered, bool IsMonotonic, 
  EmitBlock(LoopExit.getBlock());



  // Tell the runtime we are done.

  SourceLocation ELoc = S.getLocEnd();

  auto &&CodeGen = [DynamicOrOrdered, ELoc](CodeGenFunction &CGF) {

  auto &&CodeGen = [DynamicOrOrdered, &S](CodeGenFunction &CGF) {

    if (!DynamicOrOrdered)

      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, ELoc);

      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());

  };

  CodeGen(*this);



  OpenMPDirectiveKind DKind = S.getDirectiveKind();

  if (DKind == OMPD_for || DKind == OMPD_parallel_for ||

      DKind == OMPD_distribute_parallel_for)

    OMPCancelStack.back().CodeGen = CodeGen;

  OMPCancelStack.emitExit(*this, S.getDirectiveKind(), CodeGen);

}



void CodeGenFunction::EmitOMPForOuterLoop(
@@ -1889,11 +1883,12 @@ void CodeGenFunction::EmitOMPDistributeOuterLoop( 
void CodeGenFunction::EmitOMPDistributeParallelForDirective(

    const OMPDistributeParallelForDirective &S) {

  OMPLexicalScope Scope(*this, S, /*AsInlined=*/true);

  OMPCancelStackRAII CancelRegion(*this);

  CGM.getOpenMPRuntime().emitInlinedDirective(

      *this, OMPD_distribute_parallel_for,

      [&S](CodeGenFunction &CGF, PrePostActionTy &) {

        OMPLoopScope PreInitScope(CGF, S);

        OMPCancelStackRAII CancelRegion(CGF, OMPD_distribute_parallel_for,

                                        /*HasCancel=*/false);

        CGF.EmitStmt(

            cast<CapturedStmt>(S.getAssociatedStmt())->getCapturedStmt());

      });
@@ -2082,15 +2077,10 @@ bool CodeGenFunction::EmitOMPWorksharingLoop(const OMPLoopDirective &S) { 
                         [](CodeGenFunction &) {});

        EmitBlock(LoopExit.getBlock());

        // Tell the runtime we are done.

        SourceLocation ELoc = S.getLocEnd();

        auto &&CodeGen = [ELoc](CodeGenFunction &CGF) {

          CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, ELoc);

        auto &&CodeGen = [&S](CodeGenFunction &CGF) {

          CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());

        };

        CodeGen(*this);

        OpenMPDirectiveKind DKind = S.getDirectiveKind();

        if (DKind == OMPD_for || DKind == OMPD_parallel_for ||

            DKind == OMPD_distribute_parallel_for)

          OMPCancelStack.back().CodeGen = CodeGen;

        OMPCancelStack.emitExit(*this, S.getDirectiveKind(), CodeGen);

      } else {

        const bool IsMonotonic =

            Ordered || ScheduleKind.Schedule == OMPC_SCHEDULE_static ||
@@ -2140,11 +2130,11 @@ void CodeGenFunction::EmitOMPForDirective(const OMPForDirective &S) { 
  bool HasLastprivates = false;

  auto &&CodeGen = [&S, &HasLastprivates](CodeGenFunction &CGF,

                                          PrePostActionTy &) {

    OMPCancelStackRAII CancelRegion(CGF, OMPD_for, S.hasCancel());

    HasLastprivates = CGF.EmitOMPWorksharingLoop(S);

  };

  {

    OMPLexicalScope Scope(*this, S, /*AsInlined=*/true);

    OMPCancelStackRAII CancelRegion(*this);

    CGM.getOpenMPRuntime().emitInlinedDirective(*this, OMPD_for, CodeGen,

                                                S.hasCancel());

  }
@@ -2187,7 +2177,6 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) { 
  bool HasLastprivates = false;

  auto &&CodeGen = [&S, Stmt, CS, &HasLastprivates](CodeGenFunction &CGF,

                                                    PrePostActionTy &) {

    OMPCancelStackRAII CancelRegion(CGF);

    auto &C = CGF.CGM.getContext();

    auto KmpInt32Ty = C.getIntTypeForBitwidth(/*DestWidth=*/32, /*Signed=*/1);

    // Emit helper vars inits.
@@ -2282,12 +2271,10 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) { 
    CGF.EmitOMPInnerLoop(S, /*RequiresCleanup=*/false, &Cond, &Inc, BodyGen,

                         [](CodeGenFunction &) {});

    // Tell the runtime we are done.

    SourceLocation ELoc = S.getLocEnd();

    auto &&FinalCodeGen = [ELoc](CodeGenFunction &CGF) {

      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, ELoc);

    auto &&CodeGen = [&S](CodeGenFunction &CGF) {

      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());

    };

    FinalCodeGen(CGF);

    CGF.OMPCancelStack.back().CodeGen = FinalCodeGen;

    CGF.OMPCancelStack.emitExit(CGF, S.getDirectiveKind(), CodeGen);

    CGF.EmitOMPReductionClauseFinal(S);

    // Emit post-update of the reduction variables if IsLastIter != 0.

    emitPostUpdateForReductionClause(
@@ -2309,6 +2296,7 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) { 
    HasCancel = OSD->hasCancel();

  else if (auto *OPSD = dyn_cast<OMPParallelSectionsDirective>(&S))

    HasCancel = OPSD->hasCancel();

  OMPCancelStackRAII CancelRegion(*this, S.getDirectiveKind(), HasCancel);

  CGM.getOpenMPRuntime().emitInlinedDirective(*this, OMPD_sections, CodeGen,

                                              HasCancel);

  // Emit barrier for lastprivates only if 'sections' directive has 'nowait'
@@ -2412,7 +2400,7 @@ void CodeGenFunction::EmitOMPParallelForDirective( 
  // Emit directive as a combined directive that consists of two implicit

  // directives: 'parallel' with 'for' directive.

  auto &&CodeGen = [&S](CodeGenFunction &CGF, PrePostActionTy &) {

    OMPCancelStackRAII CancelRegion(CGF);

    OMPCancelStackRAII CancelRegion(CGF, OMPD_parallel_for, S.hasCancel());

    CGF.EmitOMPWorksharingLoop(S);

  };

  emitCommonOMPParallelDirective(*this, S, OMPD_for, CodeGen);
@@ -3412,14 +3400,14 @@ void CodeGenFunction::EmitOMPCancelDirective(const OMPCancelDirective &S) { 


CodeGenFunction::JumpDest

CodeGenFunction::getOMPCancelDestination(OpenMPDirectiveKind Kind) {

  if (Kind == OMPD_parallel || Kind == OMPD_task)

  if (Kind == OMPD_parallel || Kind == OMPD_task ||

      Kind == OMPD_target_parallel)

    return ReturnBlock;

  assert(Kind == OMPD_for || Kind == OMPD_section || Kind == OMPD_sections ||

         Kind == OMPD_parallel_sections || Kind == OMPD_parallel_for ||

         Kind == OMPD_distribute_parallel_for);

  if (!OMPCancelStack.back().ExitBlock.isValid())

    OMPCancelStack.back().ExitBlock = getJumpDestInCurrentScope("cancel.exit");

  return OMPCancelStack.back().ExitBlock;

         Kind == OMPD_distribute_parallel_for ||

         Kind == OMPD_target_parallel_for);

  return OMPCancelStack.getExitBlock();

}



// Generate the instructions for '#pragma omp target data' directive.

clang/lib/CodeGen/CodeGenFunction.h

+78 −19
Original line number Diff line number Diff line
@@ -965,33 +965,92 @@ private: 
  };

  SmallVector<BreakContinue, 8> BreakContinueStack;



  /// Data for exit block for proper support of OpenMP cancellation constructs.

  struct OMPCancel {

  /// Handles cancellation exit points in OpenMP-related constructs.

  class OpenMPCancelExitStack {

    /// Tracks cancellation exit point and join point for cancel-related exit

    /// and normal exit.

    struct CancelExit {

      CancelExit() = default;

      CancelExit(OpenMPDirectiveKind Kind, JumpDest ExitBlock,

                 JumpDest ContBlock)

          : Kind(Kind), ExitBlock(ExitBlock), ContBlock(ContBlock) {}

      OpenMPDirectiveKind Kind = OMPD_unknown;

      /// true if the exit block has been emitted already by the special

      /// emitExit() call, false if the default codegen is used.

      bool HasBeenEmitted = false;

      JumpDest ExitBlock;

    llvm::function_ref<void(CodeGenFunction &CGF)> CodeGen;

    OMPCancel() : CodeGen([](CodeGenFunction &CGF) {}) {}

      JumpDest ContBlock;

    };

  SmallVector<OMPCancel, 8> OMPCancelStack;



    SmallVector<CancelExit, 8> Stack;



  public:

    OpenMPCancelExitStack() : Stack(1) {}

    ~OpenMPCancelExitStack() = default;

    /// Fetches the exit block for the current OpenMP construct.

    JumpDest getExitBlock() const { return Stack.back().ExitBlock; }

    /// Emits exit block with special codegen procedure specific for the related

    /// OpenMP construct + emits code for normal construct cleanup.

    void emitExit(CodeGenFunction &CGF, OpenMPDirectiveKind Kind,

                  const llvm::function_ref<void(CodeGenFunction &)> &CodeGen) {

      if (Stack.back().Kind == Kind && getExitBlock().isValid()) {

        assert(CGF.getOMPCancelDestination(Kind).isValid());

        assert(CGF.HaveInsertPoint());

        assert(!Stack.back().HasBeenEmitted);

        auto IP = CGF.Builder.saveAndClearIP();

        CGF.EmitBlock(Stack.back().ExitBlock.getBlock());

        CodeGen(CGF);

        CGF.EmitBranchThroughCleanup(Stack.back().ContBlock);

        CGF.Builder.restoreIP(IP);

        Stack.back().HasBeenEmitted = true;

      }

      CodeGen(CGF);

    }

    /// Enter the cancel supporting \a Kind construct.

    /// \param Kind OpenMP directive that supports cancel constructs.

    /// \param HasCancel true, if the construct has inner cancel directive,

    /// false otherwise.

    void enter(CodeGenFunction &CGF, OpenMPDirectiveKind Kind, bool HasCancel) {

      Stack.push_back({Kind,

                       HasCancel ? CGF.getJumpDestInCurrentScope("cancel.exit")

                                 : JumpDest(),

                       HasCancel ? CGF.getJumpDestInCurrentScope("cancel.cont")

                                 : JumpDest()});

    }

    /// Emits default exit point for the cancel construct (if the special one

    /// has not be used) + join point for cancel/normal exits.

    void exit(CodeGenFunction &CGF) {

      if (getExitBlock().isValid()) {

        assert(CGF.getOMPCancelDestination(Stack.back().Kind).isValid());

        bool HaveIP = CGF.HaveInsertPoint();

        if (!Stack.back().HasBeenEmitted) {

          if (HaveIP)

            CGF.EmitBranchThroughCleanup(Stack.back().ContBlock);

          CGF.EmitBlock(Stack.back().ExitBlock.getBlock());

          CGF.EmitBranchThroughCleanup(Stack.back().ContBlock);

        }

        CGF.EmitBlock(Stack.back().ContBlock.getBlock());

        if (!HaveIP) {

          CGF.Builder.CreateUnreachable();

          CGF.Builder.ClearInsertionPoint();

        }

      }

      Stack.pop_back();

    }

  };

  OpenMPCancelExitStack OMPCancelStack;



  /// Controls insertion of cancellation exit blocks in worksharing constructs.

  class OMPCancelStackRAII {

    CodeGenFunction &CGF;



  public:

    OMPCancelStackRAII(CodeGenFunction &CGF) : CGF(CGF) {

      CGF.OMPCancelStack.push_back({});

    }

    ~OMPCancelStackRAII() {

      if (CGF.HaveInsertPoint() &&

          CGF.OMPCancelStack.back().ExitBlock.isValid()) {

        auto CJD = CGF.getJumpDestInCurrentScope("cancel.cont");

        CGF.EmitBranchThroughCleanup(CJD);

        CGF.EmitBlock(CGF.OMPCancelStack.back().ExitBlock.getBlock());

        CGF.OMPCancelStack.back().CodeGen(CGF);

        CGF.EmitBranchThroughCleanup(CJD);

        CGF.EmitBlock(CJD.getBlock());

      }

    OMPCancelStackRAII(CodeGenFunction &CGF, OpenMPDirectiveKind Kind,

                       bool HasCancel)

        : CGF(CGF) {

      CGF.OMPCancelStack.enter(CGF, Kind, HasCancel);

    }

    ~OMPCancelStackRAII() { CGF.OMPCancelStack.exit(CGF); }

  };



  CodeGenPGO PGO;

clang/test/OpenMP/cancel_codegen.cpp

+1 −1

File changed.

Contains only whitespace changes.