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-rw-r--r--llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp115
1 files changed, 101 insertions, 14 deletions
diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
index 83c3cec..1085564 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
@@ -161,6 +161,7 @@
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
@@ -185,6 +186,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/TypeSize.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/SSAUpdaterImpl.h"
#include <algorithm>
#include <cassert>
@@ -960,18 +962,20 @@ public:
class TransferTracker {
public:
const TargetInstrInfo *TII;
+ const TargetLowering *TLI;
/// This machine location tracker is assumed to always contain the up-to-date
/// value mapping for all machine locations. TransferTracker only reads
/// information from it. (XXX make it const?)
MLocTracker *MTracker;
MachineFunction &MF;
+ bool ShouldEmitDebugEntryValues;
/// Record of all changes in variable locations at a block position. Awkwardly
/// we allow inserting either before or after the point: MBB != nullptr
/// indicates it's before, otherwise after.
struct Transfer {
- MachineBasicBlock::iterator Pos; /// Position to insert DBG_VALUes
- MachineBasicBlock *MBB; /// non-null if we should insert after.
+ MachineBasicBlock::instr_iterator Pos; /// Position to insert DBG_VALUes
+ MachineBasicBlock *MBB; /// non-null if we should insert after.
SmallVector<MachineInstr *, 4> Insts; /// Vector of DBG_VALUEs to insert.
};
@@ -1028,9 +1032,13 @@ public:
TransferTracker(const TargetInstrInfo *TII, MLocTracker *MTracker,
MachineFunction &MF, const TargetRegisterInfo &TRI,
- const BitVector &CalleeSavedRegs)
+ const BitVector &CalleeSavedRegs, const TargetPassConfig &TPC)
: TII(TII), MTracker(MTracker), MF(MF), TRI(TRI),
- CalleeSavedRegs(CalleeSavedRegs) {}
+ CalleeSavedRegs(CalleeSavedRegs) {
+ TLI = MF.getSubtarget().getTargetLowering();
+ auto &TM = TPC.getTM<TargetMachine>();
+ ShouldEmitDebugEntryValues = TM.Options.ShouldEmitDebugEntryValues();
+ }
/// Load object with live-in variable values. \p mlocs contains the live-in
/// values in each machine location, while \p vlocs the live-in variable
@@ -1098,6 +1106,8 @@ public:
// use-before-def to be resolved as we step through the block.
if (Num.getBlock() == (unsigned)MBB.getNumber() && !Num.isPHI())
addUseBeforeDef(Var.first, Var.second.Properties, Num);
+ else
+ recoverAsEntryValue(Var.first, Var.second.Properties, Num);
continue;
}
@@ -1153,10 +1163,73 @@ public:
/// Helper to move created DBG_VALUEs into Transfers collection.
void flushDbgValues(MachineBasicBlock::iterator Pos, MachineBasicBlock *MBB) {
- if (PendingDbgValues.size() > 0) {
- Transfers.push_back({Pos, MBB, PendingDbgValues});
- PendingDbgValues.clear();
- }
+ if (PendingDbgValues.size() == 0)
+ return;
+
+ // Pick out the instruction start position.
+ MachineBasicBlock::instr_iterator BundleStart;
+ if (MBB && Pos == MBB->begin())
+ BundleStart = MBB->instr_begin();
+ else
+ BundleStart = getBundleStart(Pos->getIterator());
+
+ Transfers.push_back({BundleStart, MBB, PendingDbgValues});
+ PendingDbgValues.clear();
+ }
+
+ bool isEntryValueVariable(const DebugVariable &Var,
+ const DIExpression *Expr) const {
+ if (!Var.getVariable()->isParameter())
+ return false;
+
+ if (Var.getInlinedAt())
+ return false;
+
+ if (Expr->getNumElements() > 0)
+ return false;
+
+ return true;
+ }
+
+ bool isEntryValueValue(const ValueIDNum &Val) const {
+ // Must be in entry block (block number zero), and be a PHI / live-in value.
+ if (Val.getBlock() || !Val.isPHI())
+ return false;
+
+ // Entry values must enter in a register.
+ if (MTracker->isSpill(Val.getLoc()))
+ return false;
+
+ Register SP = TLI->getStackPointerRegisterToSaveRestore();
+ Register FP = TRI.getFrameRegister(MF);
+ Register Reg = MTracker->LocIdxToLocID[Val.getLoc()];
+ return Reg != SP && Reg != FP;
+ }
+
+ bool recoverAsEntryValue(const DebugVariable &Var, DbgValueProperties &Prop,
+ const ValueIDNum &Num) {
+ // Is this variable location a candidate to be an entry value. First,
+ // should we be trying this at all?
+ if (!ShouldEmitDebugEntryValues)
+ return false;
+
+ // Is the variable appropriate for entry values (i.e., is a parameter).
+ if (!isEntryValueVariable(Var, Prop.DIExpr))
+ return false;
+
+ // Is the value assigned to this variable still the entry value?
+ if (!isEntryValueValue(Num))
+ return false;
+
+ // Emit a variable location using an entry value expression.
+ DIExpression *NewExpr =
+ DIExpression::prepend(Prop.DIExpr, DIExpression::EntryValue);
+ Register Reg = MTracker->LocIdxToLocID[Num.getLoc()];
+ MachineOperand MO = MachineOperand::CreateReg(Reg, false);
+ MO.setIsDebug(true);
+
+ PendingDbgValues.push_back(emitMOLoc(MO, Var, {NewExpr, Prop.Indirect}));
+ return true;
}
/// Change a variable value after encountering a DBG_VALUE inside a block.
@@ -1248,8 +1321,15 @@ public:
// If there is no location, and we weren't asked to make the variable
// explicitly undef, then stop here.
- if (!NewLoc && !MakeUndef)
+ if (!NewLoc && !MakeUndef) {
+ // Try and recover a few more locations with entry values.
+ for (auto &Var : ActiveMLocIt->second) {
+ auto &Prop = ActiveVLocs.find(Var)->second.Properties;
+ recoverAsEntryValue(Var, Prop, OldValue);
+ }
+ flushDbgValues(Pos, nullptr);
return;
+ }
// Examine all the variables based on this location.
DenseSet<DebugVariable> NewMLocs;
@@ -1603,7 +1683,8 @@ private:
/// that we can compare explictly against VarLocBasedImpl.
void emitLocations(MachineFunction &MF, LiveInsT SavedLiveIns,
ValueIDNum **MOutLocs, ValueIDNum **MInLocs,
- DenseMap<DebugVariable, unsigned> &AllVarsNumbering);
+ DenseMap<DebugVariable, unsigned> &AllVarsNumbering,
+ const TargetPassConfig &TPC);
/// Boilerplate computation of some initial sets, artifical blocks and
/// RPOT block ordering.
@@ -3302,8 +3383,9 @@ void InstrRefBasedLDV::dump_mloc_transfer(
void InstrRefBasedLDV::emitLocations(
MachineFunction &MF, LiveInsT SavedLiveIns, ValueIDNum **MOutLocs,
- ValueIDNum **MInLocs, DenseMap<DebugVariable, unsigned> &AllVarsNumbering) {
- TTracker = new TransferTracker(TII, MTracker, MF, *TRI, CalleeSavedRegs);
+ ValueIDNum **MInLocs, DenseMap<DebugVariable, unsigned> &AllVarsNumbering,
+ const TargetPassConfig &TPC) {
+ TTracker = new TransferTracker(TII, MTracker, MF, *TRI, CalleeSavedRegs, TPC);
unsigned NumLocs = MTracker->getNumLocs();
// For each block, load in the machine value locations and variable value
@@ -3351,9 +3433,14 @@ void InstrRefBasedLDV::emitLocations(
MBB.insert(P.Pos, MI);
}
} else {
+ // Terminators, like tail calls, can clobber things. Don't try and place
+ // transfers after them.
+ if (P.Pos->isTerminator())
+ continue;
+
MachineBasicBlock &MBB = *P.Pos->getParent();
for (auto *MI : P.Insts) {
- MBB.insertAfter(P.Pos, MI);
+ MBB.insertAfterBundle(P.Pos, MI);
}
}
}
@@ -3520,7 +3607,7 @@ bool InstrRefBasedLDV::ExtendRanges(MachineFunction &MF,
// Using the computed value locations and variable values for each block,
// create the DBG_VALUE instructions representing the extended variable
// locations.
- emitLocations(MF, SavedLiveIns, MOutLocs, MInLocs, AllVarsNumbering);
+ emitLocations(MF, SavedLiveIns, MOutLocs, MInLocs, AllVarsNumbering, *TPC);
for (int Idx = 0; Idx < MaxNumBlocks; ++Idx) {
delete[] MOutLocs[Idx];
generated by cgit v1.1 at 2025-10-08 04:37:55 +0000