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After reading memory that's already freed.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49810 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-04-16 20:24:25 +00:00
parent 52e724ad7e
commit 9c1e06e187
3 changed files with 38 additions and 22 deletions
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38
lib/CodeGen/SimpleRegisterCoalescing.cpp
View File

@ -560,8 +560,8 @@ static void removeRange(LiveInterval &li, unsigned Start, unsigned End,
/// removeIntervalIfEmpty - Check if the live interval of a physical register
/// is empty, if so remove it and also remove the empty intervals of its
/// sub-registers.
static void removeIntervalIfEmpty(LiveInterval &li, LiveIntervals *li_,
/// sub-registers. Return true if live interval is removed.
static bool removeIntervalIfEmpty(LiveInterval &li, LiveIntervals *li_,
const TargetRegisterInfo *tri_) {
if (li.empty()) {
if (TargetRegisterInfo::isPhysicalRegister(li.reg))
@ -573,25 +573,28 @@ static void removeIntervalIfEmpty(LiveInterval &li, LiveIntervals *li_,
li_->removeInterval(*SR);
}
li_->removeInterval(li.reg);
return true;
}
return false;
}
/// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
///
void SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
/// Return true if live interval is removed.
bool SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
MachineInstr *CopyMI) {
unsigned CopyIdx = li_->getInstructionIndex(CopyMI);
LiveInterval::iterator MLR =
li.FindLiveRangeContaining(li_->getDefIndex(CopyIdx));
if (MLR == li.end())
return; // Already removed by ShortenDeadCopySrcLiveRange.
return false; // Already removed by ShortenDeadCopySrcLiveRange.
unsigned RemoveStart = MLR->start;
unsigned RemoveEnd = MLR->end;
// Remove the liverange that's defined by this.
if (RemoveEnd == li_->getDefIndex(CopyIdx)+1) {
removeRange(li, RemoveStart, RemoveEnd, li_, tri_);
removeIntervalIfEmpty(li, li_, tri_);
return removeIntervalIfEmpty(li, li_, tri_);
}
return false;
}
/// PropagateDeadness - Propagate the dead marker to the instruction which
@ -614,8 +617,8 @@ static void PropagateDeadness(LiveInterval &li, MachineInstr *CopyMI,
/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill
/// as ends the live range there. If there isn't another use, then this
/// live range is dead.
void
/// live range is dead. Return true if live interval is removed.
bool
SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
MachineInstr *CopyMI) {
unsigned CopyIdx = li_->getInstructionIndex(CopyMI);
@ -627,20 +630,19 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
mf_->begin()->removeLiveIn(li.reg);
const LiveRange *LR = li.getLiveRangeContaining(CopyIdx);
removeRange(li, LR->start, LR->end, li_, tri_);
removeIntervalIfEmpty(li, li_, tri_);
return;
return removeIntervalIfEmpty(li, li_, tri_);
}
LiveInterval::iterator LR = li.FindLiveRangeContaining(CopyIdx-1);
if (LR == li.end())
// Livein but defined by a phi.
return;
return false;
unsigned RemoveStart = LR->start;
unsigned RemoveEnd = li_->getDefIndex(CopyIdx)+1;
if (LR->end > RemoveEnd)
// More uses past this copy? Nothing to do.
return;
return false;
unsigned LastUseIdx;
MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
@ -658,7 +660,7 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
LastUseMI->getOperand(DeadIdx).setIsDead();
}
return;
return false;
}
// Is it livein?
@ -678,7 +680,7 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
PropagateDeadness(li, CopyMI, RemoveStart, li_, tri_);
removeRange(li, RemoveStart, LR->end, li_, tri_);
removeIntervalIfEmpty(li, li_, tri_);
return removeIntervalIfEmpty(li, li_, tri_);
}
/// CanCoalesceWithImpDef - Returns true if the specified copy instruction
@ -1952,8 +1954,8 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
}
if (CopyMI->registerDefIsDead(DstReg)) {
LiveInterval &li = li_->getInterval(DstReg);
ShortenDeadCopySrcLiveRange(li, CopyMI);
ShortenDeadCopyLiveRange(li, CopyMI);
if (!ShortenDeadCopySrcLiveRange(li, CopyMI))
ShortenDeadCopyLiveRange(li, CopyMI);
}
li_->RemoveMachineInstrFromMaps(*I);
(*I)->eraseFromParent();
@ -1979,8 +1981,8 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
// If def of this move instruction is dead, remove its live range
// from the dstination register's live interval.
if (mii->registerDefIsDead(dstReg)) {
ShortenDeadCopySrcLiveRange(RegInt, mii);
ShortenDeadCopyLiveRange(RegInt, mii);
if (!ShortenDeadCopySrcLiveRange(RegInt, mii))
ShortenDeadCopyLiveRange(RegInt, mii);
}
}
li_->RemoveMachineInstrFromMaps(mii);

8
lib/CodeGen/SimpleRegisterCoalescing.h
View File

@ -232,14 +232,14 @@ namespace llvm {
void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
/// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
///
void ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// Return true if live interval is removed.
bool ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill
/// as ends the live range there. If there isn't another use, then this
/// live range is dead.
void ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// live range is dead. Return true if live interval is removed.
bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// lastRegisterUse - Returns the last use of the specific register between
/// cycles Start and End or NULL if there are no uses.

14
test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll Normal file
View File

@ -0,0 +1,14 @@
; RUN: llvm-as < %s | llc -mtriple=powerpc-apple-darwin
; Avoid reading memory that's already freed.
@llvm.used = appending global [1 x i8*] [ i8* bitcast (i32 (i64)* @_Z13GetSectorSizey to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
define i32 @_Z13GetSectorSizey(i64 %Base) nounwind {
entry:
br i1 false, label %bb, label %UnifiedReturnBlock
bb: ; preds = %entry
%tmp10 = and i64 0, %Base ; <i64> [#uses=0]
ret i32 0
UnifiedReturnBlock: ; preds = %entry
ret i32 131072
}