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DebugLoc associated with a machine instruction is used to emit location entries. DebugLoc associated with a DBG_VALUE is used to identify lexical scope of the variable. After register allocation, while inserting DBG_VALUE remember original debug location for the first instruction and reuse it, otherwise dwarf writer may be mislead in identifying the variable's scope.

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llvm-svn: 124845
This commit is contained in:
Devang Patel
2011-02-04 01:43:25 +00:00
parent f7073d1445
commit 26ffa01889
3 changed files with 101 additions and 22 deletions
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49
llvm/lib/CodeGen/LiveDebugVariables.cpp
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@@ -79,7 +79,8 @@ namespace {
class UserValue {
const MDNode *variable; ///< The debug info variable we are part of.
unsigned offset; ///< Byte offset into variable.
DebugLoc dl; ///< The debug location for the variable. This is
///< used by dwarf writer to find lexical scope.
UserValue *leader; ///< Equivalence class leader.
UserValue *next; ///< Next value in equivalence class, or null.
@@ -104,8 +105,9 @@ class UserValue {
public:
/// UserValue - Create a new UserValue.
UserValue(const MDNode *var, unsigned o, LocMap::Allocator &alloc)
: variable(var), offset(o), leader(this), next(0), locInts(alloc)
UserValue(const MDNode *var, unsigned o, DebugLoc L,
LocMap::Allocator &alloc)
: variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
{}
/// getLeader - Get the leader of this value's equivalence class.
@@ -192,6 +194,11 @@ public:
void emitDebugValues(VirtRegMap *VRM,
LiveIntervals &LIS, const TargetInstrInfo &TRI);
/// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
/// variable may have more than one corresponding DBG_VALUE instructions.
/// Only first one needs DebugLoc to identify variable's lexical scope
/// in source file.
DebugLoc findDebugLoc();
void print(raw_ostream&, const TargetRegisterInfo*);
};
} // namespace
@@ -218,7 +225,7 @@ class LDVImpl {
UVMap userVarMap;
/// getUserValue - Find or create a UserValue.
UserValue *getUserValue(const MDNode *Var, unsigned Offset);
UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
/// lookupVirtReg - Find the EC leader for VirtReg or null.
UserValue *lookupVirtReg(unsigned VirtReg);
@@ -315,7 +322,8 @@ void UserValue::coalesceLocation(unsigned LocNo) {
}
}
UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset) {
UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
DebugLoc DL) {
UserValue *&Leader = userVarMap[Var];
if (Leader) {
UserValue *UV = Leader->getLeader();
@@ -325,7 +333,7 @@ UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset) {
return UV;
}
UserValue *UV = new UserValue(Var, Offset, allocator);
UserValue *UV = new UserValue(Var, Offset, DL, allocator);
userValues.push_back(UV);
Leader = UserValue::merge(Leader, UV);
return UV;
@@ -354,7 +362,7 @@ bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
// Get or create the UserValue for (variable,offset).
unsigned Offset = MI->getOperand(1).getImm();
const MDNode *Var = MI->getOperand(2).getMetadata();
UserValue *UV = getUserValue(Var, Offset);
UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
// If the location is a virtual register, make sure it is mapped.
if (MI->getOperand(0).isReg()) {
@@ -581,10 +589,10 @@ UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
DEBUG(print(dbgs(), &TRI));
}
/// findInsertLocation - Find an iterator and DebugLoc for inserting a DBG_VALUE
/// findInsertLocation - Find an iterator for inserting a DBG_VALUE
/// instruction.
static MachineBasicBlock::iterator
findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, DebugLoc &DL,
findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
LiveIntervals &LIS) {
SlotIndex Start = LIS.getMBBStartIdx(MBB);
Idx = Idx.getBaseIndex();
@@ -595,46 +603,47 @@ findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, DebugLoc &DL,
// We've reached the beginning of MBB.
if (Idx == Start) {
MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
if (I != MBB->end())
DL = I->getDebugLoc();
return I;
}
Idx = Idx.getPrevIndex();
}
// We found an instruction. The insert point is after the instr.
DL = MI->getDebugLoc();
// Don't insert anything after the first terminator, though.
return MI->getDesc().isTerminator() ? MBB->getFirstTerminator() :
llvm::next(MachineBasicBlock::iterator(MI));
}
DebugLoc UserValue::findDebugLoc() {
DebugLoc D = dl;
dl = DebugLoc();
return D;
}
void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
unsigned LocNo,
LiveIntervals &LIS,
const TargetInstrInfo &TII) {
DebugLoc DL;
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, DL, LIS);
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
MachineOperand &Loc = locations[LocNo];
// Frame index locations may require a target callback.
if (Loc.isFI()) {
MachineInstr *MI = TII.emitFrameIndexDebugValue(*MBB->getParent(),
Loc.getIndex(), offset, variable, DL);
Loc.getIndex(), offset, variable,
findDebugLoc());
if (MI) {
MBB->insert(I, MI);
return;
}
}
// This is not a frame index, or the target is happy with a standard FI.
BuildMI(*MBB, I, DL, TII.get(TargetOpcode::DBG_VALUE))
BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
.addOperand(Loc).addImm(offset).addMetadata(variable);
}
void UserValue::insertDebugKill(MachineBasicBlock *MBB, SlotIndex Idx,
LiveIntervals &LIS, const TargetInstrInfo &TII) {
DebugLoc DL;
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, DL, LIS);
BuildMI(*MBB, I, DL, TII.get(TargetOpcode::DBG_VALUE)).addReg(0)
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE)).addReg(0)
.addImm(offset).addMetadata(variable);
}