LLVM 17.0.0git
DWARFAbbreviationDeclaration.h
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1//===- DWARFAbbreviationDeclaration.h ---------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_DEBUGINFO_DWARF_DWARFABBREVIATIONDECLARATION_H
10#define LLVM_DEBUGINFO_DWARF_DWARFABBREVIATIONDECLARATION_H
11
15#include <cassert>
16#include <cstddef>
17#include <cstdint>
18
19namespace llvm {
20
21class DataExtractor;
22class DWARFFormValue;
23class DWARFUnit;
24class raw_ostream;
25
27public:
30 : Attr(A), Form(F), Value(Value) {
32 }
34 std::optional<uint8_t> ByteSize)
35 : Attr(A), Form(F) {
37 this->ByteSize.HasByteSize = ByteSize.has_value();
38 if (this->ByteSize.HasByteSize)
39 this->ByteSize.ByteSize = *ByteSize;
40 }
41
44
45 private:
46 /// The following field is used for ByteSize for non-implicit_const
47 /// attributes and as value for implicit_const ones, indicated by
48 /// Form == DW_FORM_implicit_const.
49 /// The following cases are distinguished:
50 /// * Form != DW_FORM_implicit_const and HasByteSize is true:
51 /// ByteSize contains the fixed size in bytes for the Form in this
52 /// object.
53 /// * Form != DW_FORM_implicit_const and HasByteSize is false:
54 /// byte size of Form either varies according to the DWARFUnit
55 /// that it is contained in or the value size varies and must be
56 /// decoded from the debug information in order to determine its size.
57 /// * Form == DW_FORM_implicit_const:
58 /// Value contains value for the implicit_const attribute.
59 struct ByteSizeStorage {
60 bool HasByteSize;
61 uint8_t ByteSize;
62 };
63 union {
64 ByteSizeStorage ByteSize;
65 int64_t Value;
66 };
67
68 public:
69 bool isImplicitConst() const {
70 return Form == dwarf::DW_FORM_implicit_const;
71 }
72
73 int64_t getImplicitConstValue() const {
75 return Value;
76 }
77
78 /// Get the fixed byte size of this Form if possible. This function might
79 /// use the DWARFUnit to calculate the size of the Form, like for
80 /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for
81 /// the ByteSize member.
82 std::optional<int64_t> getByteSize(const DWARFUnit &U) const;
83 };
85
87
88 uint32_t getCode() const { return Code; }
89 uint8_t getCodeByteSize() const { return CodeByteSize; }
90 dwarf::Tag getTag() const { return Tag; }
91 bool hasChildren() const { return HasChildren; }
92
95
97 return attr_iterator_range(AttributeSpecs.begin(), AttributeSpecs.end());
98 }
99
101 assert(idx < AttributeSpecs.size());
102 return AttributeSpecs[idx].Form;
103 }
104
105 size_t getNumAttributes() const {
106 return AttributeSpecs.size();
107 }
108
110 assert(idx < AttributeSpecs.size());
111 return AttributeSpecs[idx].Attr;
112 }
113
115 assert(idx < AttributeSpecs.size());
116 return AttributeSpecs[idx].isImplicitConst();
117 }
118
120 assert(idx < AttributeSpecs.size());
121 return AttributeSpecs[idx].getImplicitConstValue();
122 }
123
124 /// Get the index of the specified attribute.
125 ///
126 /// Searches the this abbreviation declaration for the index of the specified
127 /// attribute.
128 ///
129 /// \param attr DWARF attribute to search for.
130 /// \returns Optional index of the attribute if found, std::nullopt otherwise.
131 std::optional<uint32_t> findAttributeIndex(dwarf::Attribute attr) const;
132
133 /// Extract a DWARF form value from a DIE specified by DIE offset.
134 ///
135 /// Extract an attribute value for a DWARFUnit given the DIE offset and the
136 /// attribute.
137 ///
138 /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation
139 /// code in the .debug_info data.
140 /// \param Attr DWARF attribute to search for.
141 /// \param U the DWARFUnit the contains the DIE.
142 /// \returns Optional DWARF form value if the attribute was extracted.
143 std::optional<DWARFFormValue> getAttributeValue(const uint64_t DIEOffset,
144 const dwarf::Attribute Attr,
145 const DWARFUnit &U) const;
146
147 /// Compute an offset from a DIE specified by DIE offset and attribute index.
148 ///
149 /// \param AttrIndex an index of DWARF attribute.
150 /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation
151 /// code in the .debug_info data.
152 /// \param U the DWARFUnit the contains the DIE.
153 /// \returns an offset of the attribute.
155 const DWARFUnit &U) const;
156
157 /// Extract a DWARF form value from a DIE speccified by attribute index and
158 /// its offset.
159 ///
160 /// \param AttrIndex an index of DWARF attribute.
161 /// \param Offset offset of the attribute.
162 /// \param U the DWARFUnit the contains the DIE.
163 /// \returns Optional DWARF form value if the attribute was extracted.
164 std::optional<DWARFFormValue>
166 const DWARFUnit &U) const;
167
168 bool extract(DataExtractor Data, uint64_t* OffsetPtr);
169 void dump(raw_ostream &OS) const;
170
171 // Return an optional byte size of all attribute data in this abbreviation
172 // if a constant byte size can be calculated given a DWARFUnit. This allows
173 // DWARF parsing to be faster as many DWARF DIEs have a fixed byte size.
174 std::optional<size_t> getFixedAttributesByteSize(const DWARFUnit &U) const;
175
176private:
177 void clear();
178
179 /// A helper structure that can quickly determine the size in bytes of an
180 /// abbreviation declaration.
181 struct FixedSizeInfo {
182 /// The fixed byte size for fixed size forms.
183 uint16_t NumBytes = 0;
184 /// Number of DW_FORM_address forms in this abbrevation declaration.
185 uint8_t NumAddrs = 0;
186 /// Number of DW_FORM_ref_addr forms in this abbrevation declaration.
187 uint8_t NumRefAddrs = 0;
188 /// Number of 4 byte in DWARF32 and 8 byte in DWARF64 forms.
189 uint8_t NumDwarfOffsets = 0;
190
191 FixedSizeInfo() = default;
192
193 /// Calculate the fixed size in bytes given a DWARFUnit.
194 ///
195 /// \param U the DWARFUnit to use when determing the byte size.
196 /// \returns the size in bytes for all attribute data in this abbreviation.
197 /// The returned size does not include bytes for the ULEB128 abbreviation
198 /// code
199 size_t getByteSize(const DWARFUnit &U) const;
200 };
201
202 uint32_t Code;
203 dwarf::Tag Tag;
204 uint8_t CodeByteSize;
205 bool HasChildren;
206 AttributeSpecVector AttributeSpecs;
207 /// If this abbreviation has a fixed byte size then FixedAttributeSize member
208 /// variable below will have a value.
209 std::optional<FixedSizeInfo> FixedAttributeSize;
210};
211
212} // end namespace llvm
213
214#endif // LLVM_DEBUGINFO_DWARF_DWARFABBREVIATIONDECLARATION_H
static GCRegistry::Add< ErlangGC > A("erlang", "erlang-compatible garbage collector")
This file contains constants used for implementing Dwarf debug support.
loop extract
#define F(x, y, z)
Definition: MD5.cpp:55
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file defines the SmallVector class.
SmallVector< AttributeSpec, 8 > AttributeSpecVector
bool getAttrIsImplicitConstByIndex(uint32_t idx) const
iterator_range< AttributeSpecVector::const_iterator > attr_iterator_range
dwarf::Attribute getAttrByIndex(uint32_t idx) const
int64_t getAttrImplicitConstValueByIndex(uint32_t idx) const
uint64_t getAttributeOffsetFromIndex(uint32_t AttrIndex, uint64_t DIEOffset, const DWARFUnit &U) const
Compute an offset from a DIE specified by DIE offset and attribute index.
std::optional< uint32_t > findAttributeIndex(dwarf::Attribute attr) const
Get the index of the specified attribute.
std::optional< DWARFFormValue > getAttributeValue(const uint64_t DIEOffset, const dwarf::Attribute Attr, const DWARFUnit &U) const
Extract a DWARF form value from a DIE specified by DIE offset.
std::optional< size_t > getFixedAttributesByteSize(const DWARFUnit &U) const
dwarf::Form getFormByIndex(uint32_t idx) const
std::optional< DWARFFormValue > getAttributeValueFromOffset(uint32_t AttrIndex, uint64_t Offset, const DWARFUnit &U) const
Extract a DWARF form value from a DIE speccified by attribute index and its offset.
size_t size() const
Definition: SmallVector.h:91
LLVM Value Representation.
Definition: Value.h:74
A range adaptor for a pair of iterators.
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
This provides a very simple, boring adaptor for a begin and end iterator into a range type.
Attribute
Attributes.
Definition: Dwarf.h:123
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ Offset
Definition: DWP.cpp:406
AttributeSpec(dwarf::Attribute A, dwarf::Form F, int64_t Value)
AttributeSpec(dwarf::Attribute A, dwarf::Form F, std::optional< uint8_t > ByteSize)
std::optional< int64_t > getByteSize(const DWARFUnit &U) const
Get the fixed byte size of this Form if possible.