llvm-mirror/lib/CodeGen/AsmPrinter/DebugHandlerBase.h
Reid Kleckner 1e6362c860 [codeview] Generalize DIExpression parsing to handle load chains
Summary:
Hopefully this also clarifies exactly when and why we're rewriting
certiain S_LOCALs using reference types: We're using the reference type
to stand in for a zero-offset load.

Reviewers: inglorion

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D37309

llvm-svn: 312247
2017-08-31 15:56:49 +00:00

140 lines
4.8 KiB
C++

//===-- llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.h --------*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Common functionality for different debug information format backends.
// LLVM currently supports DWARF and CodeView.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGHANDLERBASE_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGHANDLERBASE_H
#include "AsmPrinterHandler.h"
#include "DbgValueHistoryCalculator.h"
#include "llvm/ADT/Optional.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/IR/DebugInfoMetadata.h"
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.
llvm::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 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;
/// 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;
/// 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() {}
// AsmPrinterHandler overrides.
public:
void beginInstruction(const MachineInstr *MI) override;
void endInstruction() override;
void beginFunction(const MachineFunction *MF) override;
void endFunction(const MachineFunction *MF) override;
/// Return Label preceding the instruction.
MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
/// Return Label immediately following the instruction.
MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
/// Determine the relative position of the fragments described by P1 and P2.
/// Returns -1 if P1 is entirely before P2, 0 if P1 and P2 overlap, 1 if P1 is
/// entirely after P2.
static int fragmentCmp(const DIExpression *P1, const DIExpression *P2);
/// Determine whether two variable fragments overlap.
static bool fragmentsOverlap(const DIExpression *P1, const DIExpression *P2);
/// If this type is derived from a base type then return base type size.
static uint64_t getBaseTypeSize(const DITypeRef TyRef);
};
}
#endif