#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
-#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
#define DEBUG_TYPE "dwarfdebug"
-STATISTIC(NumCSParams, "Number of dbg call site params created");
-
static cl::opt<bool>
DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
cl::desc("Disable debug info printing"));
}
}
-/// Try to interpret values loaded into registers that forward parameters
-/// for \p CallMI. Store parameters with interpreted value into \p Params.
-static void collectCallSiteParameters(const MachineInstr *CallMI,
- ParamSet &Params) {
- auto *MF = CallMI->getMF();
- auto CalleesMap = MF->getCallSitesInfo();
- auto CallFwdRegsInfo = CalleesMap.find(CallMI);
-
- // There is no information for the call instruction.
- if (CallFwdRegsInfo == CalleesMap.end())
- return;
-
- auto *MBB = CallMI->getParent();
- const auto &TRI = MF->getSubtarget().getRegisterInfo();
- const auto &TII = MF->getSubtarget().getInstrInfo();
- const auto &TLI = MF->getSubtarget().getTargetLowering();
-
- // Skip the call instruction.
- auto I = std::next(CallMI->getReverseIterator());
-
- DenseSet<unsigned> ArgsRegsForProcess;
- for (auto ArgReg : CallFwdRegsInfo->second)
- ArgsRegsForProcess.insert(ArgReg.Reg);
-
- // If we did not find loading a value into forwarding registers
- // that means we can try generating 'DW_OP_entry_value' for the argument
- // if a call is within entry MBB.
- DenseMap<unsigned, unsigned> RegsForEntryValues;
- bool ShouldTryEmitEntryVals = MBB->getIterator() == MF->begin();
-
- // Return true if it is an instruction over a parameter's forwarding
- // register that clobbers it.
- auto shouldInterpret = [&](const MachineInstr &MI) -> unsigned {
- if (MI.isDebugInstr())
- return 0;
- // If a MI clobbers a forwarding reg try to interpret
- // a value loaded into the reg.
- for (const MachineOperand &MO : MI.operands()) {
- if (MO.isReg() && MO.isDef() && MO.getReg() &&
- TRI->isPhysicalRegister(MO.getReg())) {
- for (auto FwdReg : ArgsRegsForProcess)
- if (TRI->regsOverlap(FwdReg, MO.getReg()))
- return FwdReg;
- }
- }
-
- return 0;
- };
-
- auto finishCallSiteParam = [&](DbgValueLoc &DbgLocVal, unsigned &Reg) {
- unsigned FwdReg = Reg;
- if (ShouldTryEmitEntryVals && RegsForEntryValues.count(Reg))
- FwdReg = RegsForEntryValues[Reg];
- DbgCallSiteParam CSParm(FwdReg, DbgLocVal);
- Params.push_back(CSParm);
- NumCSParams++;
- };
-
- // Search for a loading value in forwaring registers.
- while (I != MBB->rend()) {
- // If the next instruction is a call we can not
- // interpret parameter's forwarding registers or
- // we finished interpretation of all parameters.
- if (I->isCall())
- return;
-
- if (ArgsRegsForProcess.empty())
- return;
-
- if (unsigned Reg = shouldInterpret(*I)) {
- ArgsRegsForProcess.erase(Reg);
- const MachineOperand *Op;
- DIExpression *Expr;
- if (auto ParamValue = TII->describeLoadedValue(*I)) {
- Op = ParamValue->first;
- Expr = ParamValue->second;
- if (Op->isImm()) {
- unsigned Val = Op->getImm();
- DbgValueLoc DbgLocVal(Expr, Val);
- finishCallSiteParam(DbgLocVal, Reg);
- } else if (Op->isReg()) {
- unsigned RegLoc = Op->getReg();
- unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
- unsigned FP = TRI->getFrameRegister(*MF);
- bool IsSPorFP = (RegLoc == SP) || (RegLoc == FP);
- if (TRI->isCallerPreservedPhysReg(RegLoc, *MF) || IsSPorFP) {
- DbgValueLoc DbgLocVal(Expr, MachineLocation(RegLoc, IsSPorFP));
- finishCallSiteParam(DbgLocVal, Reg);
- } else if (ShouldTryEmitEntryVals) {
- ArgsRegsForProcess.insert(RegLoc);
- RegsForEntryValues[RegLoc] = Reg;
- }
- }
- }
- }
-
- ++I;
- }
-
- // Emit call site parameter's value as entry value.
- if (ShouldTryEmitEntryVals) {
- DIExpression *EntryExpr = DIExpression::get(MF->getFunction().getContext(),
- {dwarf::DW_OP_entry_value, 1});
- for (auto RegEntry : ArgsRegsForProcess) {
- unsigned FwdReg = RegsForEntryValues.count(RegEntry)
- ? RegsForEntryValues[RegEntry]
- : RegEntry;
- DbgValueLoc DbgLocVal(EntryExpr, MachineLocation(RegEntry));
- DbgCallSiteParam CSParm(FwdReg, DbgLocVal);
- Params.push_back(CSParm);
- NumCSParams++;
- }
- }
-}
-
void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
DwarfCompileUnit &CU, DIE &ScopeDIE,
const MachineFunction &MF) {
// for both tail and non-tail calls. Don't use DW_AT_call_all_source_calls
// because one of its requirements is not met: call site entries for
// optimized-out calls are elided.
- CU.addFlag(ScopeDIE,
- CU.getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_all_calls));
+ CU.addFlag(ScopeDIE, dwarf::DW_AT_call_all_calls);
const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
assert(TII && "TargetInstrInfo not found: cannot label tail calls");
- bool ApplyGNUExtensions = getDwarfVersion() == 4 && tuneForGDB();
// Emit call site entries for each call or tail call in the function.
for (const MachineBasicBlock &MBB : MF) {
return;
// If this is a direct call, find the callee's subprogram.
- // In the case of an indirect call find the register that holds
- // the callee.
const MachineOperand &CalleeOp = MI.getOperand(0);
- if (!CalleeOp.isGlobal() && !CalleeOp.isReg())
+ if (!CalleeOp.isGlobal())
+ continue;
+ const Function *CalleeDecl = dyn_cast<Function>(CalleeOp.getGlobal());
+ if (!CalleeDecl || !CalleeDecl->getSubprogram())
continue;
-
- unsigned CallReg = 0;
- const DISubprogram *CalleeSP = nullptr;
- const Function *CalleeDecl = nullptr;
- if (CalleeOp.isReg()) {
- CallReg = CalleeOp.getReg();
- if (!CallReg)
- continue;
- } else {
- CalleeDecl = dyn_cast<Function>(CalleeOp.getGlobal());
- if (!CalleeDecl || !CalleeDecl->getSubprogram())
- continue;
- CalleeSP = CalleeDecl->getSubprogram();
- }
// TODO: Omit call site entries for runtime calls (objc_msgSend, etc).
+ // TODO: Add support for indirect calls.
bool IsTail = TII->isTailCall(MI);
- // For tail calls, for non-gdb tuning, no return PC information is needed.
- // For regular calls (and tail calls in GDB tuning), the return PC
- // is needed to disambiguate paths in the call graph which could lead to
- // some target function.
+ // For tail calls, no return PC information is needed. For regular calls,
+ // the return PC is needed to disambiguate paths in the call graph which
+ // could lead to some target function.
const MCExpr *PCOffset =
- (IsTail && !tuneForGDB()) ? nullptr
- : getFunctionLocalOffsetAfterInsn(&MI);
-
- // Address of a call-like instruction for a normal call or a jump-like
- // instruction for a tail call. This is needed for GDB + DWARF 4 tuning.
- const MCSymbol *PCAddr =
- ApplyGNUExtensions ? const_cast<MCSymbol*>(getLabelAfterInsn(&MI))
- : nullptr;
-
- assert((IsTail || PCOffset || PCAddr) &&
- "Call without return PC information");
+ IsTail ? nullptr : getFunctionLocalOffsetAfterInsn(&MI);
+ assert((IsTail || PCOffset) && "Call without return PC information");
LLVM_DEBUG(dbgs() << "CallSiteEntry: " << MF.getName() << " -> "
- << (CalleeDecl ? CalleeDecl->getName()
- : StringRef(MF.getSubtarget()
- .getRegisterInfo()
- ->getName(CallReg)))
- << (IsTail ? " [IsTail]" : "") << "\n");
-
- DIE &CallSiteDIE =
- CU.constructCallSiteEntryDIE(ScopeDIE, CalleeSP, IsTail, PCAddr,
- PCOffset, CallReg);
-
- // For now only GDB supports call site parameter debug info.
- if (Asm->TM.Options.EnableDebugEntryValues &&
- tuneForGDB()) {
- ParamSet Params;
- // Try to interpret values of call site parameters.
- collectCallSiteParameters(&MI, Params);
- CU.constructCallSiteParmEntryDIEs(CallSiteDIE, Params);
- }
+ << CalleeDecl->getName() << (IsTail ? " [tail]" : "")
+ << "\n");
+ CU.constructCallSiteEntryDIE(ScopeDIE, *CalleeDecl->getSubprogram(),
+ IsTail, PCOffset);
}
}
}
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