#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/BasicBlock.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrDesc.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Support/LeakDetector.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Assembly/Writer.h"
#include <algorithm>
using namespace llvm;
}
void MachineBasicBlock::dump() const {
- print(errs());
+ print(dbgs());
}
static inline void OutputReg(raw_ostream &os, unsigned RegNo,
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo();
- if (TII->AnalyzeBranch(*this, TBB, FBB, Cond, true)) {
+ if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) {
// If we couldn't analyze the branch, examine the last instruction.
// If the block doesn't end in a known control barrier, assume fallthrough
// is possible. The isPredicable check is needed because this code can be
addSuccessor(New);
}
-/// BranchesToLandingPad - The basic block branches only to a landing pad or to
-/// another basic block which branches only to a landing pad. No other
-/// instructions are present other than the unconditional branch.
-bool
-MachineBasicBlock::BranchesToLandingPad(const MachineBasicBlock *MBB) const {
- SmallSet<const MachineBasicBlock*, 32> Visited;
- const MachineBasicBlock *CurMBB = MBB;
-
- while (!Visited.count(CurMBB) && !CurMBB->isLandingPad()) {
- if (CurMBB->size() != 1 || CurMBB->succ_empty() || CurMBB->succ_size() != 1)
- break;
-
- const TargetInstrInfo *TII =
- CurMBB->getParent()->getTarget().getInstrInfo();
- if (!TII->isUnpredicatedTerminator(CurMBB->begin()))
- break;
-
- Visited.insert(CurMBB);
- CurMBB = *CurMBB->succ_begin();
- }
-
- return CurMBB->isLandingPad();
-}
-
/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
/// CFG to be inserted. If we have proven that MBB can only branch to DestA and
-/// DestB, remove any other MBB successors from the CFG. DestA and DestB can
-/// be null.
+/// DestB, remove any other MBB successors from the CFG. DestA and DestB can be
+/// null.
///
/// Besides DestA and DestB, retain other edges leading to LandingPads
/// (currently there can be only one; we don't check or require that here).
bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
MachineBasicBlock *DestB,
bool isCond) {
+ // The values of DestA and DestB frequently come from a call to the
+ // 'TargetInstrInfo::AnalyzeBranch' method. We take our meaning of the initial
+ // values from there.
+ //
+ // 1. If both DestA and DestB are null, then the block ends with no branches
+ // (it falls through to its successor).
+ // 2. If DestA is set, DestB is null, and isCond is false, then the block ends
+ // with only an unconditional branch.
+ // 3. If DestA is set, DestB is null, and isCond is true, then the block ends
+ // with a conditional branch that falls through to a successor (DestB).
+ // 4. If DestA and DestB is set and isCond is true, then the block ends with a
+ // conditional branch followed by an unconditional branch. DestA is the
+ // 'true' destination and DestB is the 'false' destination.
+
bool MadeChange = false;
bool AddedFallThrough = false;
MachineFunction::iterator FallThru =
llvm::next(MachineFunction::iterator(this));
- // If this block ends with a conditional branch that falls through to its
- // successor, set DestB as the successor.
if (isCond) {
+ // If this block ends with a conditional branch that falls through to its
+ // successor, set DestB as the successor.
if (DestB == 0 && FallThru != getParent()->end()) {
DestB = FallThru;
AddedFallThrough = true;
}
} else {
// If this is an unconditional branch with no explicit dest, it must just be
- // a fallthrough into DestB.
+ // a fallthrough into DestA.
if (DestA == 0 && FallThru != getParent()->end()) {
DestA = FallThru;
AddedFallThrough = true;
}
MachineBasicBlock::succ_iterator SI = succ_begin();
- const MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
+ MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
while (SI != succ_end()) {
const MachineBasicBlock *MBB = *SI;
if (MBB == DestA) {
} else if (MBB == DestB) {
DestB = 0;
++SI;
- } else if (BranchesToLandingPad(MBB) &&
+ } else if (MBB->isLandingPad() &&
MBB != OrigDestA && MBB != OrigDestB) {
++SI;
} else {
}
}
- if (!AddedFallThrough) {
- assert(DestA == 0 && DestB == 0 &&
- "MachineCFG is missing edges!");
- } else if (isCond) {
+ if (!AddedFallThrough)
+ assert(DestA == 0 && DestB == 0 && "MachineCFG is missing edges!");
+ else if (isCond)
assert(DestA == 0 && "MachineCFG is missing edges!");
- }
return MadeChange;
}
+/// findDebugLoc - find the next valid DebugLoc starting at MBBI, skipping
+/// any DEBUG_VALUE instructions. Return UnknownLoc if there is none.
+DebugLoc
+MachineBasicBlock::findDebugLoc(MachineBasicBlock::iterator &MBBI) {
+ DebugLoc DL;
+ MachineBasicBlock::iterator E = end();
+ if (MBBI != E) {
+ // Skip debug declarations, we don't want a DebugLoc from them.
+ MachineBasicBlock::iterator MBBI2 = MBBI;
+ while (MBBI2 != E &&
+ MBBI2->getOpcode()==TargetInstrInfo::DEBUG_VALUE)
+ MBBI2++;
+ if (MBBI2 != E)
+ DL = MBBI2->getDebugLoc();
+ }
+ return DL;
+}
+
void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
bool t) {
OS << "BB#" << MBB->getNumber();
}
+
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