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Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h new file mode 100644 index 0000000..2278d4c --- /dev/null +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfAccelTable.h @@ -0,0 +1,290 @@ +//==-- llvm/CodeGen/DwarfAccelTable.h - Dwarf Accelerator Tables -*- C++ -*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for writing dwarf accelerator tables. +// +//===----------------------------------------------------------------------===// + +#ifndef CODEGEN_ASMPRINTER_DWARFACCELTABLE_H__ +#define CODEGEN_ASMPRINTER_DWARFACCELTABLE_H__ + +#include "llvm/ADT/StringMap.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/DataTypes.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/Format.h" +#include "llvm/Support/FormattedStream.h" +#include "DIE.h" +#include <vector> +#include <map> + +// The dwarf accelerator tables are an indirect hash table optimized +// for null lookup rather than access to known data. They are output into +// an on-disk format that looks like this: +// +// .-------------. +// | HEADER | +// |-------------| +// | BUCKETS | +// |-------------| +// | HASHES | +// |-------------| +// | OFFSETS | +// |-------------| +// | DATA | +// `-------------' +// +// where the header contains a magic number, version, type of hash function, +// the number of buckets, total number of hashes, and room for a special +// struct of data and the length of that struct. +// +// The buckets contain an index (e.g. 6) into the hashes array. The hashes +// section contains all of the 32-bit hash values in contiguous memory, and +// the offsets contain the offset into the data area for the particular +// hash. +// +// For a lookup example, we could hash a function name and take it modulo the +// number of buckets giving us our bucket. From there we take the bucket value +// as an index into the hashes table and look at each successive hash as long +// as the hash value is still the same modulo result (bucket value) as earlier. +// If we have a match we look at that same entry in the offsets table and +// grab the offset in the data for our final match. + +namespace llvm { + +class AsmPrinter; +class DIE; +class DwarfDebug; + +class DwarfAccelTable { + + enum HashFunctionType { + eHashFunctionDJB = 0u + }; + + static uint32_t HashDJB (StringRef Str) { + uint32_t h = 5381; + for (unsigned i = 0, e = Str.size(); i != e; ++i) + h = ((h << 5) + h) + Str[i]; + return h; + } + + // Helper function to compute the number of buckets needed based on + // the number of unique hashes. + void ComputeBucketCount (void); + + struct TableHeader { + uint32_t magic; // 'HASH' magic value to allow endian detection + uint16_t version; // Version number. + uint16_t hash_function; // The hash function enumeration that was used. + uint32_t bucket_count; // The number of buckets in this hash table. + uint32_t hashes_count; // The total number of unique hash values + // and hash data offsets in this table. + uint32_t header_data_len; // The bytes to skip to get to the hash + // indexes (buckets) for correct alignment. + // Also written to disk is the implementation specific header data. + + static const uint32_t MagicHash = 0x48415348; + + TableHeader (uint32_t data_len) : + magic (MagicHash), version (1), hash_function (eHashFunctionDJB), + bucket_count (0), hashes_count (0), header_data_len (data_len) + {} + +#ifndef NDEBUG + void print(raw_ostream &O) { + O << "Magic: " << format("0x%x", magic) << "\n" + << "Version: " << version << "\n" + << "Hash Function: " << hash_function << "\n" + << "Bucket Count: " << bucket_count << "\n" + << "Header Data Length: " << header_data_len << "\n"; + } + void dump() { print(dbgs()); } +#endif + }; + +public: + // The HeaderData describes the form of each set of data. In general this + // is as a list of atoms (atom_count) where each atom contains a type + // (AtomType type) of data, and an encoding form (form). In the case of + // data that is referenced via DW_FORM_ref_* the die_offset_base is + // used to describe the offset for all forms in the list of atoms. + // This also serves as a public interface of sorts. + // When written to disk this will have the form: + // + // uint32_t die_offset_base + // uint32_t atom_count + // atom_count Atoms + enum AtomType { + eAtomTypeNULL = 0u, + eAtomTypeDIEOffset = 1u, // DIE offset, check form for encoding + eAtomTypeCUOffset = 2u, // DIE offset of the compiler unit header that + // contains the item in question + eAtomTypeTag = 3u, // DW_TAG_xxx value, should be encoded as + // DW_FORM_data1 (if no tags exceed 255) or + // DW_FORM_data2. + eAtomTypeNameFlags = 4u, // Flags from enum NameFlags + eAtomTypeTypeFlags = 5u // Flags from enum TypeFlags + }; + + enum TypeFlags { + eTypeFlagClassMask = 0x0000000fu, + + // Always set for C++, only set for ObjC if this is the + // @implementation for a class. + eTypeFlagClassIsImplementation = ( 1u << 1 ) + }; + + // Make these public so that they can be used as a general interface to + // the class. + struct Atom { + AtomType type; // enum AtomType + uint16_t form; // DWARF DW_FORM_ defines + + Atom(AtomType type, uint16_t form) : type(type), form(form) {} + static const char * AtomTypeString(enum AtomType); +#ifndef NDEBUG + void print(raw_ostream &O) { + O << "Type: " << AtomTypeString(type) << "\n" + << "Form: " << dwarf::FormEncodingString(form) << "\n"; + } + void dump() { + print(dbgs()); + } +#endif + }; + + private: + struct TableHeaderData { + + uint32_t die_offset_base; + std::vector<Atom> Atoms; + + TableHeaderData(std::vector<DwarfAccelTable::Atom> &AtomList, + uint32_t offset = 0) : + die_offset_base(offset) { + for (size_t i = 0, e = AtomList.size(); i != e; ++i) + Atoms.push_back(AtomList[i]); + } + + TableHeaderData(DwarfAccelTable::Atom Atom, uint32_t offset = 0) + : die_offset_base(offset) { + Atoms.push_back(Atom); + } + +#ifndef NDEBUG + void print (raw_ostream &O) { + O << "die_offset_base: " << die_offset_base << "\n"; + for (size_t i = 0; i < Atoms.size(); i++) + Atoms[i].print(O); + } + void dump() { + print(dbgs()); + } +#endif + }; + + // The data itself consists of a str_offset, a count of the DIEs in the + // hash and the offsets to the DIEs themselves. + // On disk each data section is ended with a 0 KeyType as the end of the + // hash chain. + // On output this looks like: + // uint32_t str_offset + // uint32_t hash_data_count + // HashData[hash_data_count] +public: + struct HashDataContents { + DIE *Die; // Offsets + char Flags; // Specific flags to output + + HashDataContents(DIE *D, char Flags) : + Die(D), + Flags(Flags) { } + #ifndef NDEBUG + void print(raw_ostream &O) const { + O << " Offset: " << Die->getOffset() << "\n"; + O << " Tag: " << dwarf::TagString(Die->getTag()) << "\n"; + O << " Flags: " << Flags << "\n"; + } + #endif + }; +private: + struct HashData { + StringRef Str; + uint32_t HashValue; + MCSymbol *Sym; + std::vector<struct HashDataContents*> Data; // offsets + HashData(StringRef S) : Str(S) { + HashValue = DwarfAccelTable::HashDJB(S); + } + void addData(struct HashDataContents *Datum) { Data.push_back(Datum); } + #ifndef NDEBUG + void print(raw_ostream &O) { + O << "Name: " << Str << "\n"; + O << " Hash Value: " << format("0x%x", HashValue) << "\n"; + O << " Symbol: " ; + if (Sym) Sym->print(O); + else O << "<none>"; + O << "\n"; + for (size_t i = 0; i < Data.size(); i++) { + O << " Offset: " << Data[i]->Die->getOffset() << "\n"; + O << " Tag: " << dwarf::TagString(Data[i]->Die->getTag()) << "\n"; + O << " Flags: " << Data[i]->Flags << "\n"; + } + } + void dump() { + print(dbgs()); + } + #endif + }; + + DwarfAccelTable(const DwarfAccelTable&); // DO NOT IMPLEMENT + void operator=(const DwarfAccelTable&); // DO NOT IMPLEMENT + + // Internal Functions + void EmitHeader(AsmPrinter *); + void EmitBuckets(AsmPrinter *); + void EmitHashes(AsmPrinter *); + void EmitOffsets(AsmPrinter *, MCSymbol *); + void EmitData(AsmPrinter *, DwarfDebug *D); + + // Output Variables + TableHeader Header; + TableHeaderData HeaderData; + std::vector<HashData*> Data; + + // String Data + typedef std::vector<struct HashDataContents*> DataArray; + typedef StringMap<DataArray> StringEntries; + StringEntries Entries; + + // Buckets/Hashes/Offsets + typedef std::vector<HashData*> HashList; + typedef std::vector<HashList> BucketList; + BucketList Buckets; + HashList Hashes; + + // Public Implementation + public: + DwarfAccelTable(DwarfAccelTable::Atom); + DwarfAccelTable(std::vector<DwarfAccelTable::Atom> &); + ~DwarfAccelTable(); + void AddName(StringRef, DIE*, char = 0); + void FinalizeTable(AsmPrinter *, const char *); + void Emit(AsmPrinter *, MCSymbol *, DwarfDebug *); +#ifndef NDEBUG + void print(raw_ostream &O); + void dump() { print(dbgs()); } +#endif +}; + +} +#endif |
