[llvm-commits] [llvm] r128327 - in /llvm/trunk: include/llvm/CodeGen/MachineBasicBlock.h lib/CodeGen/AsmPrinter/DwarfDebug.cpp lib/CodeGen/AsmPrinter/DwarfDebug.h test/CodeGen/X86/dbg-merge-loc-entry.ll
Jakob Stoklund Olesen
stoklund at 2pi.dk
Fri Mar 25 19:19:36 PDT 2011
Author: stoklund
Date: Fri Mar 25 21:19:36 2011
New Revision: 128327
URL: http://llvm.org/viewvc/llvm-project?rev=128327&view=rev
Log:
Collect and coalesce DBG_VALUE instructions before emitting the function.
Correctly terminate the range of register DBG_VALUEs when the register is
clobbered or when the basic block ends.
The code is now ready to deal with variables that are sometimes in a register
and sometimes on the stack. We just need to teach emitDebugLoc to say 'stack
slot'.
Modified:
llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
llvm/trunk/test/CodeGen/X86/dbg-merge-loc-entry.ll
Modified: llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h?rev=128327&r1=128326&r2=128327&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h Fri Mar 25 21:19:36 2011
@@ -309,6 +309,10 @@
/// instruction in the basic block, or end()
iterator getLastNonDebugInstr();
+ const_iterator getLastNonDebugInstr() const {
+ return const_cast<MachineBasicBlock*>(this)->getLastNonDebugInstr();
+ }
+
/// SplitCriticalEdge - Split the critical edge from this block to the
/// given successor block, and return the newly created block, or null
/// if splitting is not possible.
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=128327&r1=128326&r2=128327&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Fri Mar 25 21:19:36 2011
@@ -2408,38 +2408,21 @@
/// collection info from MMI table.
collectVariableInfoFromMMITable(MF, Processed);
- SmallVector<const MachineInstr *, 8> DbgValues;
- // Collect variable information from DBG_VALUE machine instructions;
- for (MachineFunction::const_iterator I = Asm->MF->begin(), E = Asm->MF->end();
- I != E; ++I)
- for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
- II != IE; ++II) {
- const MachineInstr *MInsn = II;
- if (!MInsn->isDebugValue())
- continue;
- DbgValues.push_back(MInsn);
- }
-
- // This is a collection of DBG_VALUE instructions describing same variable.
- SmallVector<const MachineInstr *, 4> MultipleValues;
- for(SmallVector<const MachineInstr *, 8>::iterator I = DbgValues.begin(),
- E = DbgValues.end(); I != E; ++I) {
- const MachineInstr *MInsn = *I;
- MultipleValues.clear();
- if (isDbgValueInDefinedReg(MInsn))
- MultipleValues.push_back(MInsn);
- DIVariable DV(MInsn->getOperand(MInsn->getNumOperands() - 1).getMetadata());
- if (Processed.count(DV) != 0)
+ for (SmallVectorImpl<const MDNode*>::const_iterator
+ UVI = UserVariables.begin(), UVE = UserVariables.end(); UVI != UVE;
+ ++UVI) {
+ const MDNode *Var = *UVI;
+ if (Processed.count(Var))
continue;
- for (SmallVector<const MachineInstr *, 8>::iterator MI = I+1,
- ME = DbgValues.end(); MI != ME; ++MI) {
- const MDNode *Var =
- (*MI)->getOperand((*MI)->getNumOperands()-1).getMetadata();
- if (Var == DV)
- MultipleValues.push_back(*MI);
- }
+ // History contains relevant DBG_VALUE instructions for Var and instructions
+ // clobbering it.
+ SmallVectorImpl<const MachineInstr*> &History = DbgValues[Var];
+ if (History.empty())
+ continue;
+ const MachineInstr *MInsn = History.front();
+ DIVariable DV(Var);
DbgScope *Scope = NULL;
if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
DISubprogram(DV.getContext()).describes(MF->getFunction()))
@@ -2451,6 +2434,7 @@
continue;
Processed.insert(DV);
+ assert(MInsn->isDebugValue() && "History must begin with debug value");
DbgVariable *RegVar = new DbgVariable(DV);
if (!addCurrentFnArgument(MF, RegVar, Scope))
Scope->addVariable(RegVar);
@@ -2458,21 +2442,21 @@
DbgVariableToDbgInstMap[AbsVar] = MInsn;
VarToAbstractVarMap[RegVar] = AbsVar;
}
- if (MultipleValues.size() <= 1 && !RegClobberInsn.count(MInsn)) {
+
+ // Simple ranges that are fully coalesced.
+ if (History.size() <= 1 || (History.size() == 2 &&
+ MInsn->isIdenticalTo(History.back()))) {
DbgVariableToDbgInstMap[RegVar] = MInsn;
continue;
}
// handle multiple DBG_VALUE instructions describing one variable.
- if (DotDebugLocEntries.empty())
- RegVar->setDotDebugLocOffset(0);
- else
- RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
+ RegVar->setDotDebugLocOffset(DotDebugLocEntries.size());
- for (SmallVector<const MachineInstr *, 4>::iterator
- MVI = MultipleValues.begin(), MVE = MultipleValues.end();
- MVI != MVE; ++MVI) {
- const MachineInstr *Begin = *MVI;
+ for (SmallVectorImpl<const MachineInstr*>::const_iterator
+ HI = History.begin(), HE = History.end(); HI != HE; ++HI) {
+ const MachineInstr *Begin = *HI;
+ assert(Begin->isDebugValue() && "Invalid History entry");
MachineLocation MLoc;
if (Begin->getNumOperands() == 3) {
if (Begin->getOperand(0).isReg() && Begin->getOperand(1).isImm())
@@ -2480,6 +2464,7 @@
} else
MLoc = Asm->getDebugValueLocation(Begin);
+ // FIXME: emitDebugLoc only understands registers.
if (!MLoc.getReg())
continue;
@@ -2487,17 +2472,23 @@
const MCSymbol *FLabel = getLabelBeforeInsn(Begin);
const MCSymbol *SLabel = 0;
- if (const MachineInstr *ClobberMI = RegClobberInsn.lookup(Begin))
- // The register range starting at Begin may be clobbered.
- SLabel = getLabelAfterInsn(ClobberMI);
- else if (MVI + 1 == MVE)
- // If Begin is the last instruction then its value is valid
+ if (HI + 1 == HE)
+ // If Begin is the last instruction in History then its value is valid
// until the end of the funtion.
SLabel = FunctionEndSym;
- else
- // The value is valid until the next DBG_VALUE.
- SLabel = getLabelBeforeInsn(MVI[1]);
+ else {
+ const MachineInstr *End = HI[1];
+ if (End->isDebugValue())
+ SLabel = getLabelBeforeInsn(End);
+ else {
+ // End is a normal instruction clobbering the range.
+ SLabel = getLabelAfterInsn(End);
+ assert(SLabel && "Forgot label after clobber instruction");
+ ++HI;
+ }
+ }
+ // The value is valid until the next DBG_VALUE or clobber.
DotDebugLocEntries.push_back(DotDebugLocEntry(FLabel, SLabel, MLoc));
}
DotDebugLocEntries.push_back(DotDebugLocEntry());
@@ -2519,21 +2510,14 @@
/// getLabelBeforeInsn - Return Label preceding the instruction.
const MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) {
- DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
- LabelsBeforeInsn.find(MI);
- if (I == LabelsBeforeInsn.end())
- // FunctionBeginSym always preceeds all the instruction in current function.
- return FunctionBeginSym;
- return I->second;
+ MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
+ assert(Label && "Didn't insert label before instruction");
+ return Label;
}
/// getLabelAfterInsn - Return Label immediately following the instruction.
const MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) {
- DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
- LabelsAfterInsn.find(MI);
- if (I == LabelsAfterInsn.end())
- return NULL;
- return I->second;
+ return LabelsAfterInsn.lookup(MI);
}
/// beginInstruction - Process beginning of an instruction.
@@ -2552,14 +2536,22 @@
}
// Insert labels where requested.
- if (!InsnNeedsLabel.count(MI))
+ DenseMap<const MachineInstr*, MCSymbol*>::iterator I =
+ LabelsBeforeInsn.find(MI);
+
+ // No label needed.
+ if (I == LabelsBeforeInsn.end())
+ return;
+
+ // Label already assigned.
+ if (I->second)
return;
if (!PrevLabel) {
PrevLabel = MMI->getContext().CreateTempSymbol();
Asm->OutStreamer.EmitLabel(PrevLabel);
}
- LabelsBeforeInsn[MI] = PrevLabel;
+ I->second = PrevLabel;
}
/// endInstruction - Process end of an instruction.
@@ -2569,7 +2561,15 @@
if (!MI->isDebugValue())
PrevLabel = 0;
- if (!InsnsNeedsLabelAfter.count(MI))
+ DenseMap<const MachineInstr*, MCSymbol*>::iterator I =
+ LabelsAfterInsn.find(MI);
+
+ // No label needed.
+ if (I == LabelsAfterInsn.end())
+ return;
+
+ // Label already assigned.
+ if (I->second)
return;
// We need a label after this instruction.
@@ -2577,7 +2577,7 @@
PrevLabel = MMI->getContext().CreateTempSymbol();
Asm->OutStreamer.EmitLabel(PrevLabel);
}
- LabelsAfterInsn[MI] = PrevLabel;
+ I->second = PrevLabel;
}
/// getOrCreateDbgScope - Create DbgScope for the scope.
@@ -2837,8 +2837,8 @@
RE = Ranges.end(); RI != RE; ++RI) {
assert(RI->first && "DbgRange does not have first instruction!");
assert(RI->second && "DbgRange does not have second instruction!");
- InsnNeedsLabel.insert(RI->first);
- InsnsNeedsLabelAfter.insert(RI->second);
+ requestLabelBeforeInsn(RI->first);
+ requestLabelAfterInsn(RI->second);
}
}
}
@@ -2916,46 +2916,78 @@
recordSourceLine(Line, Col, TheScope);
+ assert(UserVariables.empty() && DbgValues.empty() && "Maps weren't cleaned");
+
/// ProcessedArgs - Collection of arguments already processed.
SmallPtrSet<const MDNode *, 8> ProcessedArgs;
- /// LastDbgValue - Refer back to the last DBG_VALUE instruction to mention MD.
- DenseMap<const MDNode*, const MachineInstr*> LastDbgValue;
-
const TargetRegisterInfo *TRI = Asm->TM.getRegisterInfo();
/// LiveUserVar - Map physreg numbers to the MDNode they contain.
std::vector<const MDNode*> LiveUserVar(TRI->getNumRegs());
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
- I != E; ++I)
+ I != E; ++I) {
+ bool AtBlockEntry = true;
for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
II != IE; ++II) {
const MachineInstr *MI = II;
- DebugLoc DL = MI->getDebugLoc();
+
if (MI->isDebugValue()) {
assert (MI->getNumOperands() > 1 && "Invalid machine instruction!");
- // Keep track of variables in registers.
+ // Keep track of user variables.
const MDNode *Var =
MI->getOperand(MI->getNumOperands() - 1).getMetadata();
- LastDbgValue[Var] = MI;
+
+ // Variable is in a register, we need to check for clobbers.
if (isDbgValueInDefinedReg(MI))
LiveUserVar[MI->getOperand(0).getReg()] = Var;
- DIVariable DV(Var);
- if (!DV.Verify()) continue;
- // If DBG_VALUE is for a local variable then it needs a label.
- if (DV.getTag() != dwarf::DW_TAG_arg_variable)
- InsnNeedsLabel.insert(MI);
- // DBG_VALUE for inlined functions argument needs a label.
- else if (!DISubprogram(getDISubprogram(DV.getContext())).
- describes(MF->getFunction()))
- InsnNeedsLabel.insert(MI);
- // DBG_VALUE indicating argument location change needs a label.
- else if (!ProcessedArgs.insert(DV))
- InsnNeedsLabel.insert(MI);
+ // Check the history of this variable.
+ SmallVectorImpl<const MachineInstr*> &History = DbgValues[Var];
+ if (History.empty()) {
+ UserVariables.push_back(Var);
+ // The first mention of a function argument gets the FunctionBeginSym
+ // label, so arguments are visible when breaking at function entry.
+ DIVariable DV(Var);
+ if (DV.Verify() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
+ DISubprogram(getDISubprogram(DV.getContext()))
+ .describes(MF->getFunction()))
+ LabelsBeforeInsn[MI] = FunctionBeginSym;
+ } else {
+ // We have seen this variable before. Try to coalesce DBG_VALUEs.
+ const MachineInstr *Prev = History.back();
+ if (Prev->isDebugValue()) {
+ // Coalesce identical entries at the end of History.
+ if (History.size() >= 2 &&
+ Prev->isIdenticalTo(History[History.size() - 2]))
+ History.pop_back();
+
+ // Terminate old register assignments that don't reach MI;
+ MachineFunction::const_iterator PrevMBB = Prev->getParent();
+ if (PrevMBB != I && (!AtBlockEntry || llvm::next(PrevMBB) != I) &&
+ isDbgValueInDefinedReg(Prev)) {
+ // Previous register assignment needs to terminate at the end of
+ // its basic block.
+ MachineBasicBlock::const_iterator LastMI =
+ PrevMBB->getLastNonDebugInstr();
+ if (LastMI == PrevMBB->end())
+ // Drop DBG_VALUE for empty range.
+ History.pop_back();
+ else {
+ // Terminate after LastMI.
+ History.push_back(LastMI);
+ }
+ }
+ }
+ }
+ History.push_back(MI);
} else {
+ // Not a DBG_VALUE instruction.
+ if (!MI->isLabel())
+ AtBlockEntry = false;
+
// Check if the instruction clobbers any registers with debug vars.
for (MachineInstr::const_mop_iterator MOI = MI->operands_begin(),
MOE = MI->operands_end(); MOI != MOE; ++MOI) {
@@ -2970,19 +3002,57 @@
LiveUserVar[Reg] = 0;
// Was MD last defined by a DBG_VALUE referring to Reg?
- const MachineInstr *Last = LastDbgValue.lookup(Var);
- if (!Last || Last->getParent() != MI->getParent())
+ DbgValueHistoryMap::iterator HistI = DbgValues.find(Var);
+ if (HistI == DbgValues.end())
continue;
- if (!isDbgValueInDefinedReg(Last) ||
- Last->getOperand(0).getReg() != Reg)
+ SmallVectorImpl<const MachineInstr*> &History = HistI->second;
+ if (History.empty())
continue;
- // MD is clobbered. Make sure the next instruction gets a label.
- InsnsNeedsLabelAfter.insert(MI);
- RegClobberInsn[Last] = MI;
+ const MachineInstr *Prev = History.back();
+ // Sanity-check: Register assignments are terminated at the end of
+ // their block.
+ if (!Prev->isDebugValue() || Prev->getParent() != MI->getParent())
+ continue;
+ // Is the variable still in Reg?
+ if (!isDbgValueInDefinedReg(Prev) ||
+ Prev->getOperand(0).getReg() != Reg)
+ continue;
+ // Var is clobbered. Make sure the next instruction gets a label.
+ History.push_back(MI);
}
}
}
}
+ }
+
+ for (DbgValueHistoryMap::iterator I = DbgValues.begin(), E = DbgValues.end();
+ I != E; ++I) {
+ SmallVectorImpl<const MachineInstr*> &History = I->second;
+ if (History.empty())
+ continue;
+
+ // Make sure the final register assignments are terminated.
+ const MachineInstr *Prev = History.back();
+ if (Prev->isDebugValue() && isDbgValueInDefinedReg(Prev)) {
+ const MachineBasicBlock *PrevMBB = Prev->getParent();
+ MachineBasicBlock::const_iterator LastMI = PrevMBB->getLastNonDebugInstr();
+ if (LastMI == PrevMBB->end())
+ // Drop DBG_VALUE for empty range.
+ History.pop_back();
+ else {
+ // Terminate after LastMI.
+ History.push_back(LastMI);
+ }
+ }
+ // Request labels for the full history.
+ for (unsigned i = 0, e = History.size(); i != e; ++i) {
+ const MachineInstr *MI = History[i];
+ if (MI->isDebugValue())
+ requestLabelBeforeInsn(MI);
+ else
+ requestLabelAfterInsn(MI);
+ }
+ }
PrevInstLoc = DebugLoc();
PrevLabel = FunctionBeginSym;
@@ -3043,13 +3113,12 @@
// Clear debug info
CurrentFnDbgScope = NULL;
CurrentFnArguments.clear();
- InsnNeedsLabel.clear();
DbgVariableToFrameIndexMap.clear();
VarToAbstractVarMap.clear();
DbgVariableToDbgInstMap.clear();
DeleteContainerSeconds(DbgScopeMap);
- InsnsNeedsLabelAfter.clear();
- RegClobberInsn.clear();
+ UserVariables.clear();
+ DbgValues.clear();
ConcreteScopes.clear();
DeleteContainerSeconds(AbstractScopes);
AbstractScopesList.clear();
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=128327&r1=128326&r2=128327&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Fri Mar 25 21:19:36 2011
@@ -218,19 +218,16 @@
/// instruction.
DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
- /// insnNeedsLabel - Collection of instructions that need a label to mark
- /// a debuggging information entity.
- SmallPtrSet<const MachineInstr *, 8> InsnNeedsLabel;
-
- /// InsnsNeedsLabelAfter - Collection of instructions that need a label after
- /// the instruction because they end a scope of clobber a register.
- SmallPtrSet<const MachineInstr *, 8> InsnsNeedsLabelAfter;
-
- /// RegClobberInsn - For each DBG_VALUE instruction referring to a register
- /// that is clobbered before the variable gets a new DBG_VALUE, map the
- /// instruction that clobbered the register. This instruction will also be in
- /// InsnsNeedsLabelAfter.
- DenseMap<const MachineInstr *, const MachineInstr *> RegClobberInsn;
+ /// UserVariables - Every user variable mentioned by a DBG_VALUE instruction
+ /// in order of appearance.
+ SmallVector<const MDNode*, 8> UserVariables;
+
+ /// DbgValues - For each user variable, keep a list of DBG_VALUE
+ /// instructions in order. The list can also contain normal instructions that
+ /// clobber the previous DBG_VALUE.
+ typedef DenseMap<const MDNode*, SmallVector<const MachineInstr*, 4> >
+ DbgValueHistoryMap;
+ DbgValueHistoryMap DbgValues;
SmallVector<const MCSymbol *, 8> DebugRangeSymbols;
@@ -570,6 +567,23 @@
/// side table maintained by MMI.
void collectVariableInfoFromMMITable(const MachineFunction * MF,
SmallPtrSet<const MDNode *, 16> &P);
+
+ /// requestLabelBeforeInsn - Ensure that a label will be emitted before MI.
+ void requestLabelBeforeInsn(const MachineInstr *MI) {
+ LabelsBeforeInsn.insert(std::make_pair(MI, (MCSymbol*)0));
+ }
+
+ /// getLabelBeforeInsn - Return Label preceding the instruction.
+ const MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
+
+ /// requestLabelAfterInsn - Ensure that a label will be emitted after MI.
+ void requestLabelAfterInsn(const MachineInstr *MI) {
+ LabelsAfterInsn.insert(std::make_pair(MI, (MCSymbol*)0));
+ }
+
+ /// getLabelAfterInsn - Return Label immediately following the instruction.
+ const MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
+
public:
//===--------------------------------------------------------------------===//
// Main entry points.
@@ -593,12 +607,6 @@
///
void endFunction(const MachineFunction *MF);
- /// getLabelBeforeInsn - Return Label preceding the instruction.
- const MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
-
- /// getLabelAfterInsn - Return Label immediately following the instruction.
- const MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
-
/// beginInstruction - Process beginning of an instruction.
void beginInstruction(const MachineInstr *MI);
Modified: llvm/trunk/test/CodeGen/X86/dbg-merge-loc-entry.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/dbg-merge-loc-entry.ll?rev=128327&r1=128326&r2=128327&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/dbg-merge-loc-entry.ll (original)
+++ llvm/trunk/test/CodeGen/X86/dbg-merge-loc-entry.ll Fri Mar 25 21:19:36 2011
@@ -4,7 +4,7 @@
;CHECK: Ldebug_loc0:
;CHECK-NEXT: .quad Lfunc_begin0
-;CHECK-NEXT: .quad Lfunc_end0
+;CHECK-NEXT: .quad L
;CHECK-NEXT: .short 1 ## Loc expr size
;CHECK-NEXT: .byte 85 ## DW_OP_reg5
;CHECK-NEXT: .quad 0
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