| //===- DWARFAbbreviationDeclaration.h ---------------------------*- 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H |
| #define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H |
| |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/iterator_range.h" |
| #include "llvm/BinaryFormat/Dwarf.h" |
| #include "llvm/Support/DataExtractor.h" |
| #include <cassert> |
| #include <cstddef> |
| #include <cstdint> |
| |
| namespace llvm { |
| |
| class DWARFFormValue; |
| class DWARFUnit; |
| class raw_ostream; |
| |
| class DWARFAbbreviationDeclaration { |
| public: |
| struct AttributeSpec { |
| AttributeSpec(dwarf::Attribute A, dwarf::Form F, int64_t Value) |
| : Attr(A), Form(F), Value(Value) { |
| assert(isImplicitConst()); |
| } |
| AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<uint8_t> ByteSize) |
| : Attr(A), Form(F) { |
| assert(!isImplicitConst()); |
| this->ByteSize.HasByteSize = ByteSize.hasValue(); |
| if (this->ByteSize.HasByteSize) |
| this->ByteSize.ByteSize = *ByteSize; |
| } |
| |
| dwarf::Attribute Attr; |
| dwarf::Form Form; |
| |
| private: |
| /// The following field is used for ByteSize for non-implicit_const |
| /// attributes and as value for implicit_const ones, indicated by |
| /// Form == DW_FORM_implicit_const. |
| /// The following cases are distinguished: |
| /// * Form != DW_FORM_implicit_const and HasByteSize is true: |
| /// ByteSize contains the fixed size in bytes for the Form in this |
| /// object. |
| /// * Form != DW_FORM_implicit_const and HasByteSize is false: |
| /// byte size of Form either varies according to the DWARFUnit |
| /// that it is contained in or the value size varies and must be |
| /// decoded from the debug information in order to determine its size. |
| /// * Form == DW_FORM_implicit_const: |
| /// Value contains value for the implicit_const attribute. |
| struct ByteSizeStorage { |
| bool HasByteSize; |
| uint8_t ByteSize; |
| }; |
| union { |
| ByteSizeStorage ByteSize; |
| int64_t Value; |
| }; |
| |
| public: |
| bool isImplicitConst() const { |
| return Form == dwarf::DW_FORM_implicit_const; |
| } |
| |
| int64_t getImplicitConstValue() const { |
| assert(isImplicitConst()); |
| return Value; |
| } |
| |
| /// Get the fixed byte size of this Form if possible. This function might |
| /// use the DWARFUnit to calculate the size of the Form, like for |
| /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for |
| /// the ByteSize member. |
| Optional<int64_t> getByteSize(const DWARFUnit &U) const; |
| }; |
| using AttributeSpecVector = SmallVector<AttributeSpec, 8>; |
| |
| DWARFAbbreviationDeclaration(); |
| |
| uint32_t getCode() const { return Code; } |
| uint8_t getCodeByteSize() const { return CodeByteSize; } |
| dwarf::Tag getTag() const { return Tag; } |
| bool hasChildren() const { return HasChildren; } |
| |
| using attr_iterator_range = |
| iterator_range<AttributeSpecVector::const_iterator>; |
| |
| attr_iterator_range attributes() const { |
| return attr_iterator_range(AttributeSpecs.begin(), AttributeSpecs.end()); |
| } |
| |
| dwarf::Form getFormByIndex(uint32_t idx) const { |
| assert(idx < AttributeSpecs.size()); |
| return AttributeSpecs[idx].Form; |
| } |
| |
| size_t getNumAttributes() const { |
| return AttributeSpecs.size(); |
| } |
| |
| dwarf::Attribute getAttrByIndex(uint32_t idx) const { |
| assert(idx < AttributeSpecs.size()); |
| return AttributeSpecs[idx].Attr; |
| } |
| |
| /// Get the index of the specified attribute. |
| /// |
| /// Searches the this abbreviation declaration for the index of the specified |
| /// attribute. |
| /// |
| /// \param attr DWARF attribute to search for. |
| /// \returns Optional index of the attribute if found, None otherwise. |
| Optional<uint32_t> findAttributeIndex(dwarf::Attribute attr) const; |
| |
| /// Extract a DWARF form value from a DIE specified by DIE offset. |
| /// |
| /// Extract an attribute value for a DWARFUnit given the DIE offset and the |
| /// attribute. |
| /// |
| /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation |
| /// code in the .debug_info data. |
| /// \param Attr DWARF attribute to search for. |
| /// \param U the DWARFUnit the contains the DIE. |
| /// \returns Optional DWARF form value if the attribute was extracted. |
| Optional<DWARFFormValue> getAttributeValue(const uint32_t DIEOffset, |
| const dwarf::Attribute Attr, |
| const DWARFUnit &U) const; |
| |
| bool extract(DataExtractor Data, uint32_t* OffsetPtr); |
| void dump(raw_ostream &OS) const; |
| |
| // Return an optional byte size of all attribute data in this abbreviation |
| // if a constant byte size can be calculated given a DWARFUnit. This allows |
| // DWARF parsing to be faster as many DWARF DIEs have a fixed byte size. |
| Optional<size_t> getFixedAttributesByteSize(const DWARFUnit &U) const; |
| |
| private: |
| void clear(); |
| |
| /// A helper structure that can quickly determine the size in bytes of an |
| /// abbreviation declaration. |
| struct FixedSizeInfo { |
| /// The fixed byte size for fixed size forms. |
| uint16_t NumBytes = 0; |
| /// Number of DW_FORM_address forms in this abbrevation declaration. |
| uint8_t NumAddrs = 0; |
| /// Number of DW_FORM_ref_addr forms in this abbrevation declaration. |
| uint8_t NumRefAddrs = 0; |
| /// Number of 4 byte in DWARF32 and 8 byte in DWARF64 forms. |
| uint8_t NumDwarfOffsets = 0; |
| |
| FixedSizeInfo() = default; |
| |
| /// Calculate the fixed size in bytes given a DWARFUnit. |
| /// |
| /// \param U the DWARFUnit to use when determing the byte size. |
| /// \returns the size in bytes for all attribute data in this abbreviation. |
| /// The returned size does not include bytes for the ULEB128 abbreviation |
| /// code |
| size_t getByteSize(const DWARFUnit &U) const; |
| }; |
| |
| uint32_t Code; |
| dwarf::Tag Tag; |
| uint8_t CodeByteSize; |
| bool HasChildren; |
| AttributeSpecVector AttributeSpecs; |
| /// If this abbreviation has a fixed byte size then FixedAttributeSize member |
| /// variable below will have a value. |
| Optional<FixedSizeInfo> FixedAttributeSize; |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H |