#define LLVM_CODEGEN_ANALYSIS_H
#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/IR/CallSite.h"
namespace llvm {
class GlobalValue;
+class MachineBasicBlock;
+class MachineFunction;
class TargetLoweringBase;
class TargetLowering;
class TargetMachine;
// or we are in LTO.
bool canBeOmittedFromSymbolTable(const GlobalValue *GV);
+DenseMap<const MachineBasicBlock *, int>
+getFuncletMembership(const MachineFunction &MF);
+
} // End llvm namespace
#endif
#include "llvm/CodeGen/Analysis.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/Utils/GlobalStatus.h"
return !GS.IsCompared;
}
+
+static void collectFuncletMembers(
+ DenseMap<const MachineBasicBlock *, int> &FuncletMembership, int Funclet,
+ const MachineBasicBlock *MBB) {
+ // Don't revisit blocks.
+ if (FuncletMembership.count(MBB) > 0) {
+ if (FuncletMembership[MBB] != Funclet) {
+ assert(false && "MBB is part of two funclets!");
+ report_fatal_error("MBB is part of two funclets!");
+ }
+ return;
+ }
+
+ // Add this MBB to our funclet.
+ FuncletMembership[MBB] = Funclet;
+
+ bool IsReturn = false;
+ int NumTerminators = 0;
+ for (const MachineInstr &MI : MBB->terminators()) {
+ IsReturn |= MI.isReturn();
+ ++NumTerminators;
+ }
+ assert((!IsReturn || NumTerminators == 1) &&
+ "Expected only one terminator when a return is present!");
+
+ // Returns are boundaries where funclet transfer can occur, don't follow
+ // successors.
+ if (IsReturn)
+ return;
+
+ for (const MachineBasicBlock *SMBB : MBB->successors())
+ if (!SMBB->isEHPad())
+ collectFuncletMembers(FuncletMembership, Funclet, SMBB);
+}
+
+DenseMap<const MachineBasicBlock *, int>
+llvm::getFuncletMembership(const MachineFunction &MF) {
+ DenseMap<const MachineBasicBlock *, int> FuncletMembership;
+
+ // We don't have anything to do if there aren't any EH pads.
+ if (!MF.getMMI().hasEHFunclets())
+ return FuncletMembership;
+
+ bool IsSEH = isAsynchronousEHPersonality(
+ classifyEHPersonality(MF.getFunction()->getPersonalityFn()));
+
+ const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
+ SmallVector<const MachineBasicBlock *, 16> FuncletBlocks;
+ SmallVector<std::pair<const MachineBasicBlock *, int>, 16> CatchRetSuccessors;
+ for (const MachineBasicBlock &MBB : MF) {
+ if (MBB.isEHFuncletEntry())
+ FuncletBlocks.push_back(&MBB);
+
+ MachineBasicBlock::const_iterator MBBI = MBB.getFirstTerminator();
+ // CatchPads are not funclets for SEH so do not consider CatchRet to
+ // transfer control to another funclet.
+ if (IsSEH || MBBI->getOpcode() != TII->getCatchReturnOpcode())
+ continue;
+
+ const MachineBasicBlock *Successor = MBBI->getOperand(0).getMBB();
+ const MachineBasicBlock *SuccessorColor = MBBI->getOperand(1).getMBB();
+ CatchRetSuccessors.push_back({Successor, SuccessorColor->getNumber()});
+ }
+
+ // We don't have anything to do if there aren't any EH pads.
+ if (FuncletBlocks.empty())
+ return FuncletMembership;
+
+ // Identify all the basic blocks reachable from the function entry.
+ collectFuncletMembers(FuncletMembership, MF.front().getNumber(), MF.begin());
+ // Next, identify all the blocks inside the funclets.
+ for (const MachineBasicBlock *MBB : FuncletBlocks)
+ collectFuncletMembers(FuncletMembership, MBB->getNumber(), MBB);
+ // Finally, identify all the targets of a catchret.
+ for (std::pair<const MachineBasicBlock *, int> CatchRetPair :
+ CatchRetSuccessors)
+ collectFuncletMembers(FuncletMembership, CatchRetPair.second,
+ CatchRetPair.first);
+ // All blocks not part of a funclet are in the parent function.
+ for (const MachineBasicBlock &MBB : MF)
+ FuncletMembership.insert({&MBB, MF.front().getNumber()});
+ return FuncletMembership;
+}
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
TargetPassConfig *PassConfig = &getAnalysis<TargetPassConfig>();
// TailMerge can create jump into if branches that make CFG irreducible for
- // HW that requires structurized CFG. It can also cause BBs to get shared
- // between funclets.
+ // HW that requires structurized CFG.
bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() &&
- !MF.getMMI().hasEHFunclets() &&
PassConfig->getEnableTailMerge();
BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true,
getAnalysis<MachineBlockFrequencyInfo>(),
// Remove the block.
MF->erase(MBB);
+ FuncletMembership.erase(MBB);
}
/// OptimizeImpDefsBlock - If a basic block is just a bunch of implicit_def
MadeChange |= OptimizeImpDefsBlock(&MBB);
}
+ // Recalculate funclet membership.
+ FuncletMembership = getFuncletMembership(MF);
+
bool MadeChangeThisIteration = true;
while (MadeChangeThisIteration) {
MadeChangeThisIteration = TailMergeBlocks(MF);
// For targets that use the register scavenger, we must maintain LiveIns.
MaintainLiveIns(&CurMBB, NewMBB);
+ // Add the new block to the funclet.
+ const auto &FuncletI = FuncletMembership.find(&CurMBB);
+ if (FuncletI != FuncletMembership.end())
+ FuncletMembership[NewMBB] = FuncletI->second;
+
return NewMBB;
}
/// and decide if it would be profitable to merge those tails. Return the
/// length of the common tail and iterators to the first common instruction
/// in each block.
-static bool ProfitableToMerge(MachineBasicBlock *MBB1,
- MachineBasicBlock *MBB2,
- unsigned minCommonTailLength,
- unsigned &CommonTailLen,
- MachineBasicBlock::iterator &I1,
- MachineBasicBlock::iterator &I2,
- MachineBasicBlock *SuccBB,
- MachineBasicBlock *PredBB) {
+static bool
+ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
+ unsigned minCommonTailLength, unsigned &CommonTailLen,
+ MachineBasicBlock::iterator &I1,
+ MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB,
+ MachineBasicBlock *PredBB,
+ DenseMap<const MachineBasicBlock *, int> &FuncletMembership) {
+ // It is never profitable to tail-merge blocks from two different funclets.
+ if (!FuncletMembership.empty()) {
+ auto Funclet1 = FuncletMembership.find(MBB1);
+ assert(Funclet1 != FuncletMembership.end());
+ auto Funclet2 = FuncletMembership.find(MBB2);
+ assert(Funclet2 != FuncletMembership.end());
+ if (Funclet1->second != Funclet2->second)
+ return false;
+ }
+
CommonTailLen = ComputeCommonTailLength(MBB1, MBB2, I1, I2);
if (CommonTailLen == 0)
return false;
if (ProfitableToMerge(CurMPIter->getBlock(), I->getBlock(),
minCommonTailLength,
CommonTailLen, TrialBBI1, TrialBBI2,
- SuccBB, PredBB)) {
+ SuccBB, PredBB,
+ FuncletMembership)) {
if (CommonTailLen > maxCommonTailLength) {
SameTails.clear();
maxCommonTailLength = CommonTailLen;
// Make sure blocks are numbered in order
MF.RenumberBlocks();
+ // Renumbering blocks alters funclet membership, recalculate it.
+ FuncletMembership = getFuncletMembership(MF);
for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end();
I != E; ) {
++NumDeadBlocks;
}
}
+
return MadeChange;
}
MachineFunction::iterator FallThrough = MBB;
++FallThrough;
+ // Make sure MBB and FallThrough belong to the same funclet.
+ bool SameFunclet = true;
+ if (!FuncletMembership.empty() && FallThrough != MF.end()) {
+ auto MBBFunclet = FuncletMembership.find(MBB);
+ assert(MBBFunclet != FuncletMembership.end());
+ auto FallThroughFunclet = FuncletMembership.find(FallThrough);
+ assert(FallThroughFunclet != FuncletMembership.end());
+ SameFunclet = MBBFunclet->second == FallThroughFunclet->second;
+ }
+
// If this block is empty, make everyone use its fall-through, not the block
// explicitly. Landing pads should not do this since the landing-pad table
// points to this block. Blocks with their addresses taken shouldn't be
// optimized away.
- if (IsEmptyBlock(MBB) && !MBB->isEHPad() && !MBB->hasAddressTaken()) {
+ if (IsEmptyBlock(MBB) && !MBB->isEHPad() && !MBB->hasAddressTaken() &&
+ SameFunclet) {
// Dead block? Leave for cleanup later.
if (MBB->pred_empty()) return MadeChange;
typedef std::vector<MergePotentialsElt>::iterator MPIterator;
std::vector<MergePotentialsElt> MergePotentials;
SmallPtrSet<const MachineBasicBlock*, 2> TriedMerging;
+ DenseMap<const MachineBasicBlock *, int> FuncletMembership;
class SameTailElt {
MPIterator MPIter;
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
#define DEBUG_TYPE "funclet-layout"
};
}
-static void
-collectFuncletMembers(DenseMap<MachineBasicBlock *, int> &FuncletMembership,
- int Funclet, MachineBasicBlock *MBB) {
- // Don't revisit blocks.
- if (FuncletMembership.count(MBB) > 0) {
- if (FuncletMembership[MBB] != Funclet) {
- assert(false && "MBB is part of two funclets!");
- report_fatal_error("MBB is part of two funclets!");
- }
- return;
- }
-
- // Add this MBB to our funclet.
- FuncletMembership[MBB] = Funclet;
-
- bool IsReturn = false;
- int NumTerminators = 0;
- for (MachineInstr &MI : MBB->terminators()) {
- IsReturn |= MI.isReturn();
- ++NumTerminators;
- }
- assert((!IsReturn || NumTerminators == 1) &&
- "Expected only one terminator when a return is present!");
-
- // Returns are boundaries where funclet transfer can occur, don't follow
- // successors.
- if (IsReturn)
- return;
-
- for (MachineBasicBlock *SMBB : MBB->successors())
- if (!SMBB->isEHPad())
- collectFuncletMembers(FuncletMembership, Funclet, SMBB);
-}
-
char FuncletLayout::ID = 0;
char &llvm::FuncletLayoutID = FuncletLayout::ID;
INITIALIZE_PASS(FuncletLayout, "funclet-layout",
"Contiguously Lay Out Funclets", false, false)
bool FuncletLayout::runOnMachineFunction(MachineFunction &F) {
- // We don't have anything to do if there aren't any EH pads.
- if (!F.getMMI().hasEHFunclets())
+ DenseMap<const MachineBasicBlock *, int> FuncletMembership =
+ getFuncletMembership(F);
+ if (FuncletMembership.empty())
return false;
- const TargetInstrInfo *TII = F.getSubtarget().getInstrInfo();
- SmallVector<MachineBasicBlock *, 16> FuncletBlocks;
- SmallVector<std::pair<MachineBasicBlock *, int>, 16> CatchRetSuccessors;
- for (MachineBasicBlock &MBB : F) {
- if (MBB.isEHFuncletEntry())
- FuncletBlocks.push_back(&MBB);
-
- MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
- if (MBBI->getOpcode() != TII->getCatchReturnOpcode())
- continue;
-
- MachineBasicBlock *Successor = MBBI->getOperand(0).getMBB();
- MachineBasicBlock *SuccessorColor = MBBI->getOperand(1).getMBB();
- CatchRetSuccessors.push_back({Successor, SuccessorColor->getNumber()});
- }
-
- // We don't have anything to do if there aren't any EH pads.
- if (FuncletBlocks.empty())
- return false;
-
- DenseMap<MachineBasicBlock *, int> FuncletMembership;
- // Identify all the basic blocks reachable from the function entry.
- collectFuncletMembers(FuncletMembership, F.front().getNumber(), F.begin());
- // Next, identify all the blocks inside the funclets.
- for (MachineBasicBlock *MBB : FuncletBlocks)
- collectFuncletMembers(FuncletMembership, MBB->getNumber(), MBB);
- // Finally, identify all the targets of a catchret.
- for (std::pair<MachineBasicBlock *, int> CatchRetPair : CatchRetSuccessors)
- collectFuncletMembers(FuncletMembership, CatchRetPair.second,
- CatchRetPair.first);
-
F.sort([&](MachineBasicBlock &x, MachineBasicBlock &y) {
return FuncletMembership[&x] < FuncletMembership[&y];
});
; CHECK: retq
-define void @test3() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+define void @test3(i1 %V) #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
entry:
invoke void @g()
to label %try.cont unwind label %catch.dispatch
catchendpad unwind to caller
try.cont: ; preds = %entry
- ret void
+ br i1 %V, label %exit_one, label %exit_two
+
+exit_one:
+ tail call void @exit(i32 0)
+ unreachable
+
+exit_two:
+ tail call void @exit(i32 0)
+ unreachable
}
; CHECK-LABEL: test3:
; The entry funclet contains %entry and %try.cont
; CHECK: # %entry
; CHECK: # %try.cont
-; CHECK: retq
+; CHECK: callq exit
+; CHECK-NOT: # exit_one
+; CHECK-NOT: # exit_two
+; CHECK: ud2
; The catch(int) funclet contains %catch.2
; CHECK: # %catch.2
; CHECK: callq exit
+; CHECK: ud2
; The catch(...) funclet contains %catch
; CHECK: # %catch{{$}}
; CHECK: callq exit
+; CHECK: ud2
declare void @exit(i32) noreturn nounwind
declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
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