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//===-- llvm/CodeGen/DIEHash.h - Dwarf Hashing Framework -------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file contains support for DWARF4 hashing of DIEs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/Support/MD5.h"
namespace llvm {
class AsmPrinter;
/// An object containing the capability of hashing and adding hash
/// attributes onto a DIE.
class DIEHash {
// Collection of all attributes used in hashing a particular DIE.
struct DIEAttrs {
#define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME;
#include "DIEHashAttributes.def"
};
public:
DIEHash(AsmPrinter *A = nullptr, DwarfCompileUnit *CU = nullptr)
: AP(A), CU(CU) {}
/// Computes the CU signature.
uint64_t computeCUSignature(StringRef DWOName, const DIE &Die);
/// Computes the type signature.
uint64_t computeTypeSignature(const DIE &Die);
// Helper routines to process parts of a DIE.
private:
/// Adds the parent context of \param Parent to the hash.
void addParentContext(const DIE &Parent);
/// Adds the attributes of \param Die to the hash.
void addAttributes(const DIE &Die);
/// Computes the full DWARF4 7.27 hash of the DIE.
void computeHash(const DIE &Die);
// Routines that add DIEValues to the hash.
public:
/// Adds \param Value to the hash.
void update(uint8_t Value) { Hash.update(Value); }
/// Encodes and adds \param Value to the hash as a ULEB128.
void addULEB128(uint64_t Value);
/// Encodes and adds \param Value to the hash as a SLEB128.
void addSLEB128(int64_t Value);
private:
/// Adds \param Str to the hash and includes a NULL byte.
void addString(StringRef Str);
/// Collects the attributes of DIE \param Die into the \param Attrs
/// structure.
void collectAttributes(const DIE &Die, DIEAttrs &Attrs);
/// Hashes the attributes in \param Attrs in order.
void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag);
/// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
/// DW_FORM_exprloc.
void hashBlockData(const DIE::const_value_range &Values);
/// Hashes the contents pointed to in the .debug_loc section.
void hashLocList(const DIELocList &LocList);
/// Hashes an individual attribute.
void hashAttribute(const DIEValue &Value, dwarf::Tag Tag);
/// Hashes an attribute that refers to another DIE.
void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
const DIE &Entry);
/// Hashes a reference to a named type in such a way that is
/// independent of whether that type is described by a declaration or a
/// definition.
void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry,
StringRef Name);
/// Hashes a reference to a previously referenced type DIE.
void hashRepeatedTypeReference(dwarf::Attribute Attribute,
unsigned DieNumber);
void hashNestedType(const DIE &Die, StringRef Name);
private:
MD5 Hash;
AsmPrinter *AP;
DwarfCompileUnit *CU;
DenseMap<const DIE *, unsigned> Numbering;
};
}
#endif
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