From 31ed50c225c8de764c899e31ab4e25f242ce0b78 Mon Sep 17 00:00:00 2001 From: Eric Christopher Date: Fri, 1 Nov 2013 23:14:17 +0000 Subject: Comment some and reformat for clarity beginFunction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193894 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 72 ++++++++++++++++++++--------------- 1 file changed, 42 insertions(+), 30 deletions(-) (limited to 'lib') diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index d18b7a55d3..632f1ab58b 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -1595,13 +1595,25 @@ static DebugLoc getFnDebugLoc(DebugLoc DL, const LLVMContext &Ctx) { // Gather pre-function debug information. Assumes being called immediately // after the function entry point has been emitted. void DwarfDebug::beginFunction(const MachineFunction *MF) { - if (!MMI->hasDebugInfo()) return; + + // If there's no debug info for the function we're not going to do anything. + if (!MMI->hasDebugInfo()) + return; + + // Grab the lexical scopes for the function, if we don't have any of those + // then we're not going to be able to do anything. LScopes.initialize(*MF); - if (LScopes.empty()) return; + if (LScopes.empty()) + return; + + assert(UserVariables.empty() && DbgValues.empty() && "Maps weren't cleaned"); + + // Make sure that each lexical scope will have a begin/end label. identifyScopeMarkers(); // Set DwarfCompileUnitID in MCContext to the Compile Unit this function - // belongs to. + // belongs to so that we add to the correct per-cu line table in the + // non-asm case. LexicalScope *FnScope = LScopes.getCurrentFunctionScope(); CompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode()); assert(TheCU && "Unable to find compile unit!"); @@ -1611,19 +1623,17 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { else Asm->OutStreamer.getContext().setDwarfCompileUnitID(TheCU->getUniqueID()); - FunctionBeginSym = Asm->GetTempSymbol("func_begin", - Asm->getFunctionNumber()); + // Emit a label for the function so that we have a beginning address. + FunctionBeginSym = Asm->GetTempSymbol("func_begin", Asm->getFunctionNumber()); // Assumes in correct section after the entry point. Asm->OutStreamer.EmitLabel(FunctionBeginSym); - assert(UserVariables.empty() && DbgValues.empty() && "Maps weren't cleaned"); - const TargetRegisterInfo *TRI = Asm->TM.getRegisterInfo(); // LiveUserVar - Map physreg numbers to the MDNode they contain. - std::vector LiveUserVar(TRI->getNumRegs()); + std::vector LiveUserVar(TRI->getNumRegs()); - for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); - I != E; ++I) { + for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E; + ++I) { bool AtBlockEntry = true; for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end(); II != IE; ++II) { @@ -1634,14 +1644,14 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { // Keep track of user variables. const MDNode *Var = - MI->getOperand(MI->getNumOperands() - 1).getMetadata(); + MI->getOperand(MI->getNumOperands() - 1).getMetadata(); // Variable is in a register, we need to check for clobbers. if (isDbgValueInDefinedReg(MI)) LiveUserVar[MI->getOperand(0).getReg()] = Var; // Check the history of this variable. - SmallVectorImpl &History = DbgValues[Var]; + SmallVectorImpl &History = DbgValues[Var]; if (History.empty()) { UserVariables.push_back(Var); // The first mention of a function argument gets the FunctionBeginSym @@ -1649,7 +1659,7 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { DIVariable DV(Var); if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable && DISubprogram(getDISubprogram(DV.getContext())) - .describes(MF->getFunction())) + .describes(MF->getFunction())) LabelsBeforeInsn[MI] = FunctionBeginSym; } else { // We have seen this variable before. Try to coalesce DBG_VALUEs. @@ -1659,8 +1669,8 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { if (History.size() >= 2 && Prev->isIdenticalTo(History[History.size() - 2])) { DEBUG(dbgs() << "Coalescing identical DBG_VALUE entries:\n" - << "\t" << *Prev - << "\t" << *History[History.size() - 2] << "\n"); + << "\t" << *Prev << "\t" + << *History[History.size() - 2] << "\n"); History.pop_back(); } @@ -1671,11 +1681,11 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { // Previous register assignment needs to terminate at the end of // its basic block. MachineBasicBlock::const_iterator LastMI = - PrevMBB->getLastNonDebugInstr(); + PrevMBB->getLastNonDebugInstr(); if (LastMI == PrevMBB->end()) { // Drop DBG_VALUE for empty range. DEBUG(dbgs() << "Dropping DBG_VALUE for empty range:\n" - << "\t" << *Prev << "\n"); + << "\t" << *Prev << "\n"); History.pop_back(); } else if (llvm::next(PrevMBB) != PrevMBB->getParent()->end()) // Terminate after LastMI. @@ -1697,11 +1707,12 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { // 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) { + MOE = MI->operands_end(); + MOI != MOE; ++MOI) { if (!MOI->isReg() || !MOI->isDef() || !MOI->getReg()) continue; - for (MCRegAliasIterator AI(MOI->getReg(), TRI, true); - AI.isValid(); ++AI) { + for (MCRegAliasIterator AI(MOI->getReg(), TRI, true); AI.isValid(); + ++AI) { unsigned Reg = *AI; const MDNode *Var = LiveUserVar[Reg]; if (!Var) @@ -1713,7 +1724,7 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { DbgValueHistoryMap::iterator HistI = DbgValues.find(Var); if (HistI == DbgValues.end()) continue; - SmallVectorImpl &History = HistI->second; + SmallVectorImpl &History = HistI->second; if (History.empty()) continue; const MachineInstr *Prev = History.back(); @@ -1735,7 +1746,7 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { for (DbgValueHistoryMap::iterator I = DbgValues.begin(), E = DbgValues.end(); I != E; ++I) { - SmallVectorImpl &History = I->second; + SmallVectorImpl &History = I->second; if (History.empty()) continue; @@ -1744,7 +1755,7 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { if (Prev->isDebugValue() && isDbgValueInDefinedReg(Prev)) { const MachineBasicBlock *PrevMBB = Prev->getParent(); MachineBasicBlock::const_iterator LastMI = - PrevMBB->getLastNonDebugInstr(); + PrevMBB->getLastNonDebugInstr(); if (LastMI == PrevMBB->end()) // Drop DBG_VALUE for empty range. History.pop_back(); @@ -1768,13 +1779,14 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) { // Record beginning of function. if (!PrologEndLoc.isUnknown()) { - DebugLoc FnStartDL = getFnDebugLoc(PrologEndLoc, - MF->getFunction()->getContext()); - recordSourceLine(FnStartDL.getLine(), FnStartDL.getCol(), - FnStartDL.getScope(MF->getFunction()->getContext()), - // We'd like to list the prologue as "not statements" but GDB behaves - // poorly if we do that. Revisit this with caution/GDB (7.5+) testing. - DWARF2_FLAG_IS_STMT); + DebugLoc FnStartDL = + getFnDebugLoc(PrologEndLoc, MF->getFunction()->getContext()); + recordSourceLine( + FnStartDL.getLine(), FnStartDL.getCol(), + FnStartDL.getScope(MF->getFunction()->getContext()), + // We'd like to list the prologue as "not statements" but GDB behaves + // poorly if we do that. Revisit this with caution/GDB (7.5+) testing. + DWARF2_FLAG_IS_STMT); } } -- cgit v1.2.3