#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/BasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.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/Assembly/Writer.h"
+#include "llvm/ADT/SmallString.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;
LeakDetector::removeGarbageObject(this);
}
+/// getSymbol - Return the MCSymbol for this basic block.
+///
+MCSymbol *MachineBasicBlock::getSymbol(MCContext &Ctx) const {
+ SmallString<60> Name;
+ const MachineFunction *MF = getParent();
+ raw_svector_ostream(Name)
+ << MF->getTarget().getMCAsmInfo()->getPrivateGlobalPrefix() << "BB"
+ << MF->getFunctionNumber() << '_' << getNumber();
+ return Ctx.GetOrCreateSymbol(Name.str());
+}
+
+
raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineBasicBlock &MBB) {
MBB.print(OS);
return OS;
return I;
}
-/// isOnlyReachableViaFallthough - Return true if this basic block has
-/// exactly one predecessor and the control transfer mechanism between
-/// the predecessor and this block is a fall-through.
-bool MachineBasicBlock::isOnlyReachableByFallthrough() const {
- // If this is a landing pad, it isn't a fall through. If it has no preds,
- // then nothing falls through to it.
- if (isLandingPad() || pred_empty())
- return false;
-
- // If there isn't exactly one predecessor, it can't be a fall through.
- const_pred_iterator PI = pred_begin(), PI2 = PI;
- ++PI2;
- if (PI2 != pred_end())
- return false;
-
- // The predecessor has to be immediately before this block.
- const MachineBasicBlock *Pred = *PI;
-
- if (!Pred->isLayoutSuccessor(this))
- return false;
-
- // If the block is completely empty, then it definitely does fall through.
- if (Pred->empty())
- return true;
-
- // Otherwise, check the last instruction.
- const MachineInstr &LastInst = Pred->back();
- return !LastInst.getDesc().isBarrier();
-}
-
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
/// 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).
/// Note it is possible that DestA and/or DestB are LandingPads.
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;
MachineBasicBlock::succ_iterator SI = succ_begin();
MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
while (SI != succ_end()) {
- if (*SI == DestA) {
+ const MachineBasicBlock *MBB = *SI;
+ if (MBB == DestA) {
DestA = 0;
++SI;
- } else if (*SI == DestB) {
+ } else if (MBB == DestB) {
DestB = 0;
++SI;
- } else if ((*SI)->isLandingPad() &&
- *SI!=OrigDestA && *SI!=OrigDestB) {
+ } else if (MBB->isLandingPad() &&
+ MBB != OrigDestA && MBB != OrigDestB) {
++SI;
} else {
// Otherwise, this is a superfluous edge, remove it.
MadeChange = true;
}
}
- 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 DBG_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->isDebugValue())
+ MBBI2++;
+ if (MBBI2 != E)
+ DL = MBBI2->getDebugLoc();
+ }
+ return DL;
+}
+
void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
bool t) {
OS << "BB#" << MBB->getNumber();
}
+
projects / oota-llvm.git / blobdiff