WIP [readobj][AArch64] Parse AArch64 build attributes #124276
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| //=== - AArch64AttributeParser.h-AArch64 Attribute Information Printer - ===// | ||
| // | ||
| // 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 | ||
| // | ||
| //===--------------------------------------------------------------------===// | ||
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| #ifndef LLVM_SUPPORT_AARCH64ATTRIBUTEPARSER_H | ||
| #define LLVM_SUPPORT_AARCH64ATTRIBUTEPARSER_H | ||
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| #include "ELFAttributeParser.h" | ||
| #include "llvm/Support/Error.h" | ||
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| namespace llvm { | ||
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| class ScopedPrinter; | ||
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| class AArch64AttributeParser : public ELFAttributeParser { | ||
| Error handler(uint64_t Tag, bool &Handled) override { | ||
| return Error::success(); | ||
| } | ||
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| public: | ||
| Error parse(ArrayRef<uint8_t> Section, llvm::endianness Endian) override; | ||
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| AArch64AttributeParser(ScopedPrinter *Sw) : ELFAttributeParser(Sw) {} | ||
| AArch64AttributeParser() {} | ||
| }; | ||
| } // namespace llvm | ||
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| #endif // LLVM_SUPPORT_AARCH64ATTRIBUTEPARSER_H |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,152 @@ | ||
| //===-AArch64AttributeParser.cpp-AArch64 Attribute Information Printer-===// | ||
| // | ||
| // 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 | ||
| // | ||
| //===------------------------------------------------------------------===// | ||
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| #include "llvm/Support/AArch64AttributeParser.h" | ||
| #include "llvm/ADT/StringExtras.h" | ||
| #include "llvm/ADT/StringRef.h" | ||
| #include "llvm/Support/AArch64BuildAttributes.h" | ||
| #include "llvm/Support/Errc.h" | ||
| #include "llvm/Support/Error.h" | ||
| #include "llvm/Support/ScopedPrinter.h" | ||
| #include "llvm/Support/raw_ostream.h" | ||
| #include <cstdint> | ||
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| using namespace llvm; | ||
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| Error AArch64AttributeParser::parse(ArrayRef<uint8_t> Section, | ||
| llvm::endianness Endian) { | ||
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| unsigned SectionNumber = 0; | ||
| de = DataExtractor(Section, Endian == llvm::endianness::little, 0); | ||
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| // Early returns have specific errors. Consume the Error in cursor. | ||
| struct ClearCursorError { | ||
| DataExtractor::Cursor &Cursor; | ||
| ~ClearCursorError() { consumeError(Cursor.takeError()); } | ||
| } Clear{cursor}; | ||
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| /* | ||
| AArch64 build attributes layout: | ||
| <format-version: ‘A’> --> There is only one version, 'A' (0x41) | ||
| [ <uint32: subsection-length> <NTBS: vendor-name> <bytes: vendor-data> ] | ||
| --> subsection-length: the offset from the start of this subsection to the | ||
| start of the next one. | ||
| --> vendor-name: NUL-terminated byte string. | ||
| --> vendor-data expands to: | ||
| [ <uint8: optional> <uint8: parameter type> <attribute>*] | ||
| --> optional: 0- required, 1- optional | ||
| --> type: 0- ULEB128, 1- NTBS | ||
| --> attribute: <tag, value>* pair. Tag is ULEB128, value is <parameter | ||
| type> type. | ||
| */ | ||
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| // Get format-version | ||
| uint8_t FormatVersion = de.getU8(cursor); | ||
| if (ELFAttrs::Format_Version != FormatVersion) | ||
| return createStringError(errc::invalid_argument, | ||
| "unrecognized format-version: 0x" + | ||
| utohexstr(FormatVersion)); | ||
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| while (!de.eof(cursor)) { | ||
| uint32_t BASubsectionLength = de.getU32(cursor); | ||
| // Minimal valid BA subsection header size is at least 8: length(4) name(at | ||
| // least a single char + null) optionality(1) and type(1) | ||
| if (BASubsectionLength < 8) | ||
| return createStringError( | ||
| errc::invalid_argument, | ||
| "invalid AArch64 build attribute subsection size at offset: " + | ||
| utohexstr(cursor.tell() - 4)); | ||
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| StringRef VendorName = de.getCStrRef(cursor); | ||
| // The layout of a private subsection (--> vendor name does not starts with | ||
| // 'aeabi') is unknown, skip) | ||
| if (!VendorName.starts_with("aeabi")) { | ||
| sw->startLine() | ||
| << "** Skipping private AArch64 build attributes subsection: " | ||
| << VendorName << "\n"; | ||
| // Offset in Section | ||
| uint64_t OffsetInSection = cursor.tell(); | ||
| // Size: 4 bytes, Vendor Name: VendorName.size() + 1 (null termination) | ||
| uint32_t BytesForLengthName = 4 + (VendorName.size() + 1); | ||
| cursor.seek(OffsetInSection + BASubsectionLength - BytesForLengthName); | ||
| continue; | ||
| } | ||
| // All public subsections names must be known | ||
| if (VendorName.starts_with("aeabi")) { | ||
| if (!("aeabi_feature_and_bits" == VendorName || | ||
|
There was a problem hiding this comment. We should be able to print any "aeabi*" subsection, because the format is known, even if the tag names aren't. |
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| "aeabi_pauthabi" == VendorName)) { | ||
| return createStringError( | ||
| errc::invalid_argument, | ||
| "unknown public AArch64 build attribute subsection name at " | ||
| "offset: " + | ||
| utohexstr(cursor.tell() - (VendorName.size() + 1))); | ||
| } | ||
| } | ||
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| uint8_t IsOptional = de.getU8(cursor); | ||
| StringRef IsOptionalStr = IsOptional ? "optional" : "required"; | ||
| uint8_t Type = de.getU8(cursor); | ||
| StringRef TypeStr = Type ? "ntbs" : "uleb128"; | ||
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| if (sw) { | ||
| sw->startLine() << "Section " << ++SectionNumber << " {\n"; | ||
| sw->indent(); | ||
| sw->printNumber("SectionLength", BASubsectionLength); | ||
| sw->startLine() << "VendorName" << ": " << VendorName | ||
| << " Optionality: " << IsOptionalStr | ||
| << " Type: " << TypeStr << "\n"; | ||
| sw->startLine() << "Attributes {\n"; | ||
| sw->indent(); | ||
| } | ||
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| // Offset in Section | ||
| uint64_t OffsetInSection = cursor.tell(); | ||
| // Size: 4 bytes, Vendor Name: VendorName.size() + 1 (null termination), | ||
| // optionality: 1, size: 1 | ||
| uint32_t BytesAllButAttributes = 4 + (VendorName.size() + 1) + 1 + 1; | ||
| while (cursor.tell() < | ||
| (OffsetInSection + BASubsectionLength - BytesAllButAttributes)) { | ||
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| uint64_t Tag = de.getULEB128(cursor); | ||
| std::string Str = utostr(Tag); | ||
| StringRef TagStr(Str); | ||
| if ("aeabi_feature_and_bits" == VendorName) { | ||
| StringRef TagAsString = | ||
| AArch64BuildAttributes::getFeatureAndBitsTagsStr(Tag); | ||
| if ("" != TagAsString) | ||
| TagStr = TagAsString; | ||
| } | ||
| if ("aeabi_pauthabi" == VendorName) { | ||
| StringRef TagAsString = AArch64BuildAttributes::getPauthABITagsStr(Tag); | ||
| if ("" != TagAsString) | ||
| TagStr = TagAsString; | ||
| } | ||
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| if (Type) { // type==1 --> ntbs | ||
| StringRef Value = de.getCStrRef(cursor); | ||
| if (sw) | ||
| sw->printString(TagStr, Value); | ||
| } else { // type==0 --> uleb128 | ||
| uint64_t Value = de.getULEB128(cursor); | ||
| if (sw) | ||
| sw->printNumber(TagStr, Value); | ||
| } | ||
| } | ||
| if (sw) { | ||
| // Close 'Attributes' | ||
| sw->unindent(); | ||
| sw->startLine() << "}\n"; | ||
| // Close 'Section' | ||
| sw->unindent(); | ||
| sw->startLine() << "}\n"; | ||
| } | ||
| } | ||
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| return cursor.takeError(); | ||
| } | ||
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This is completely replacing the
parsefunction in the base class, which I think makes the design more complicated because there is lots of code now in the base class which is only sometimes used.I think it would be better to split out parsing of the two sub-classes to parse the ARM-style (also used by other architectures) and AArch64-style (currently AArch64 only, but not guaranteed to remain AArch64-specific). This would leave the base class as an abstract class without an implementation of the
parsefunction. The architecture-specific classes can then derive from one of the new classes, depending on which format it uses.The new
AArch64AttributeParserimplementation also only implements some of the behaviour ofELFAttributeParser, for example it does not populate theattributesmap, so thegetAttributeValueandgetAttributeStringfunctions will fail. This should either implement all of the functionality provided by the base class, or the parts not needed for the AArch64-style attributes should be moved to the ARM-style class.