//===-- llvm/CodeGen/DebugHandlerBase.h -----------------------*- C++ -*--===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Common functionality for different debug information format backends.
// LLVM currently supports DWARF and CodeView.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_DEBUGHANDLERBASE_H
#define LLVM_CODEGEN_DEBUGHANDLERBASE_H
#include "llvm/CodeGen/AsmPrinterHandler.h"
#include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include <optional>
namespace llvm {
class AsmPrinter;
class MachineInstr;
class MachineModuleInfo;
/// Represents the location at which a variable is stored.
struct DbgVariableLocation {
/// Base register.
unsigned Register;
/// Chain of offsetted loads necessary to load the value if it lives in
/// memory. Every load except for the last is pointer-sized.
SmallVector<int64_t, 1> LoadChain;
/// Present if the location is part of a larger variable.
std::optional<llvm::DIExpression::FragmentInfo> FragmentInfo;
/// Extract a VariableLocation from a MachineInstr.
/// This will only work if Instruction is a debug value instruction
/// and the associated DIExpression is in one of the supported forms.
/// If these requirements are not met, the returned Optional will not
/// have a value.
static std::optional<DbgVariableLocation>
extractFromMachineInstruction(const MachineInstr &Instruction);
};
/// Base class for debug information backends. Common functionality related to
/// tracking which variables and scopes are alive at a given PC live here.
class DebugHandlerBase : public AsmPrinterHandler {
protected:
DebugHandlerBase(AsmPrinter *A);
/// Target of debug info emission.
AsmPrinter *Asm;
/// Collected machine module information.
MachineModuleInfo *MMI;
/// Previous instruction's location information. This is used to
/// determine label location to indicate scope boundaries in debug info.
/// We track the previous instruction's source location (if not line 0),
/// whether it was a label, and its parent BB.
DebugLoc PrevInstLoc;
MCSymbol *PrevLabel = nullptr;
const MachineBasicBlock *PrevInstBB = nullptr;
/// This location indicates end of function prologue and beginning of
/// function body.
DebugLoc PrologEndLoc;
/// This block includes epilogue instructions.
const MachineBasicBlock *EpilogBeginBlock;
/// If nonnull, stores the current machine instruction we're processing.
const MachineInstr *CurMI = nullptr;
LexicalScopes LScopes;
/// History of DBG_VALUE and clobber instructions for each user
/// variable. Variables are listed in order of appearance.
DbgValueHistoryMap DbgValues;
/// Mapping of inlined labels and DBG_LABEL machine instruction.
DbgLabelInstrMap DbgLabels;
/// Maps instruction with label emitted before instruction.
/// FIXME: Make this private from DwarfDebug, we have the necessary accessors
/// for it.
DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
/// Maps instruction with label emitted after instruction.
DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
/// Indentify instructions that are marking the beginning of or
/// ending of a scope.
void identifyScopeMarkers();
/// Ensure that a label will be emitted before MI.
void requestLabelBeforeInsn(const MachineInstr *MI) {
LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
}
/// Ensure that a label will be emitted after MI.
void requestLabelAfterInsn(const MachineInstr *MI) {
LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
}
virtual void beginFunctionImpl(const MachineFunction *MF) = 0;
virtual void endFunctionImpl(const MachineFunction *MF) = 0;
virtual void skippedNonDebugFunction() {}
private:
InstructionOrdering InstOrdering;
// AsmPrinterHandler overrides.
public:
void beginModule(Module *M) override;
void beginInstruction(const MachineInstr *MI) override;
void endInstruction() override;
void beginFunction(const MachineFunction *MF) override;
void endFunction(const MachineFunction *MF) override;
void beginBasicBlockSection(const MachineBasicBlock &MBB) override;
void endBasicBlockSection(const MachineBasicBlock &MBB) override;
/// Return Label preceding the instruction.
MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
/// Return Label immediately following the instruction.
MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
/// If this type is derived from a base type then return base type size.
static uint64_t getBaseTypeSize(const DIType *Ty);
/// Return true if type encoding is unsigned.
static bool isUnsignedDIType(const DIType *Ty);
const InstructionOrdering &getInstOrdering() const { return InstOrdering; }
};
} // namespace llvm
#endif