2bddab25db
Instead of hashing DIE offsets, hash DIE references the same as they would be when used outside of a loclist - that is, deep hash the type on first use, and hash the numbering on subsequent uses. This does produce different hashes for different type references, where it did not before (because we were hashing zero all the time - so it didn't matter what type was referenced, the hash would be identical). This also allows us to enforce that the DIE offset (& size) is not queried before it is used (which came up while investigating another bug recently).
139 lines
4.5 KiB
C++
139 lines
4.5 KiB
C++
//===-- llvm/CodeGen/ByteStreamer.h - ByteStreamer class --------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains a class that can take bytes that would normally be
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// streamed via the AsmPrinter.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
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#define LLVM_LIB_CODEGEN_ASMPRINTER_BYTESTREAMER_H
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#include "DIEHash.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Support/LEB128.h"
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#include <string>
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namespace llvm {
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class ByteStreamer {
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protected:
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~ByteStreamer() = default;
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ByteStreamer(const ByteStreamer&) = default;
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ByteStreamer() = default;
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public:
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// For now we're just handling the calls we need for dwarf emission/hashing.
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virtual void emitInt8(uint8_t Byte, const Twine &Comment = "") = 0;
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virtual void emitSLEB128(uint64_t DWord, const Twine &Comment = "") = 0;
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virtual void emitULEB128(uint64_t DWord, const Twine &Comment = "",
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unsigned PadTo = 0) = 0;
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virtual void emitDIERef(const DIE &D) = 0;
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};
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class APByteStreamer final : public ByteStreamer {
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private:
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AsmPrinter &AP;
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public:
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APByteStreamer(AsmPrinter &Asm) : AP(Asm) {}
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void emitInt8(uint8_t Byte, const Twine &Comment) override {
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AP.OutStreamer->AddComment(Comment);
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AP.emitInt8(Byte);
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}
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void emitSLEB128(uint64_t DWord, const Twine &Comment) override {
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AP.OutStreamer->AddComment(Comment);
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AP.emitSLEB128(DWord);
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}
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void emitULEB128(uint64_t DWord, const Twine &Comment,
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unsigned PadTo) override {
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AP.OutStreamer->AddComment(Comment);
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AP.emitULEB128(DWord, nullptr, PadTo);
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}
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void emitDIERef(const DIE &D) override {
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uint64_t Offset = D.getOffset();
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static constexpr unsigned ULEB128PadSize = 4;
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assert(Offset < (1ULL << (ULEB128PadSize * 7)) && "Offset wont fit");
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emitULEB128(Offset, "", ULEB128PadSize);
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}
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};
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class HashingByteStreamer final : public ByteStreamer {
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private:
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DIEHash &Hash;
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public:
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HashingByteStreamer(DIEHash &H) : Hash(H) {}
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void emitInt8(uint8_t Byte, const Twine &Comment) override {
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Hash.update(Byte);
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}
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void emitSLEB128(uint64_t DWord, const Twine &Comment) override {
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Hash.addSLEB128(DWord);
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}
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void emitULEB128(uint64_t DWord, const Twine &Comment,
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unsigned PadTo) override {
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Hash.addULEB128(DWord);
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}
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void emitDIERef(const DIE &D) override { Hash.hashRawTypeReference(D); }
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};
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class BufferByteStreamer final : public ByteStreamer {
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private:
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SmallVectorImpl<char> &Buffer;
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std::vector<std::string> &Comments;
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public:
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/// Only verbose textual output needs comments. This will be set to
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/// true for that case, and false otherwise. If false, comments passed in to
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/// the emit methods will be ignored.
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const bool GenerateComments;
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BufferByteStreamer(SmallVectorImpl<char> &Buffer,
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std::vector<std::string> &Comments, bool GenerateComments)
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: Buffer(Buffer), Comments(Comments), GenerateComments(GenerateComments) {
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}
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void emitInt8(uint8_t Byte, const Twine &Comment) override {
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Buffer.push_back(Byte);
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if (GenerateComments)
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Comments.push_back(Comment.str());
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}
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void emitSLEB128(uint64_t DWord, const Twine &Comment) override {
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raw_svector_ostream OSE(Buffer);
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unsigned Length = encodeSLEB128(DWord, OSE);
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if (GenerateComments) {
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Comments.push_back(Comment.str());
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// Add some empty comments to keep the Buffer and Comments vectors aligned
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// with each other.
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for (size_t i = 1; i < Length; ++i)
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Comments.push_back("");
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}
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}
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void emitULEB128(uint64_t DWord, const Twine &Comment,
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unsigned PadTo) override {
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raw_svector_ostream OSE(Buffer);
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unsigned Length = encodeULEB128(DWord, OSE, PadTo);
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if (GenerateComments) {
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Comments.push_back(Comment.str());
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// Add some empty comments to keep the Buffer and Comments vectors aligned
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// with each other.
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for (size_t i = 1; i < Length; ++i)
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Comments.push_back("");
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}
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}
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void emitDIERef(const DIE &D) override {
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uint64_t Offset = D.getOffset();
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static constexpr unsigned ULEB128PadSize = 4;
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assert(Offset < (1ULL << (ULEB128PadSize * 7)) && "Offset wont fit");
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emitULEB128(Offset, "", ULEB128PadSize);
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}
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};
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}
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#endif
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