================
@@ -940,6 +940,92 @@ ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec, const
Elf_Shdr *RelaSec,
return std::move(AddrMapsOrErr);
}
+template <class ELFT>
+Expected<std::vector<FuncMap>>
+ELFFile<ELFT>::decodeFuncMap(const Elf_Shdr &Sec,
+ const Elf_Shdr *RelaSec) const {
+ bool IsRelocatable = this->getHeader().e_type == ELF::ET_REL;
+
+ // This DenseMap maps the offset of each function (the location of the
+ // reference to the function in the SHT_LLVM_FUNC_MAP section) to the
+ // addend (the location of the function in the text section).
+ llvm::DenseMap<uint64_t, uint64_t> FunctionOffsetTranslations;
+ if (IsRelocatable && RelaSec) {
+ assert(RelaSec &&
+ "Can't read a SHT_LLVM_FUNC_ADDR_MAP section in a relocatable "
+ "object file without providing a relocation section.");
+ Expected<typename ELFFile<ELFT>::Elf_Rela_Range> Relas =
+ this->relas(*RelaSec);
+ if (!Relas)
+ return createError("unable to read relocations for section " +
+ describe(*this, Sec) + ": " +
+ toString(Relas.takeError()));
+ for (typename ELFFile<ELFT>::Elf_Rela Rela : *Relas)
+ FunctionOffsetTranslations[Rela.r_offset] = Rela.r_addend;
+ }
+ auto GetAddressForRelocation =
+ [&](unsigned RelocationOffsetInSection) -> Expected<unsigned> {
+ auto FOTIterator =
+ FunctionOffsetTranslations.find(RelocationOffsetInSection);
+ if (FOTIterator == FunctionOffsetTranslations.end()) {
+ return createError("failed to get relocation data for offset: " +
+ Twine::utohexstr(RelocationOffsetInSection) +
+ " in section " + describe(*this, Sec));
+ }
+ return FOTIterator->second;
+ };
+ Expected<ArrayRef<uint8_t>> ContentsOrErr = this->getSectionContents(Sec);
+ if (!ContentsOrErr)
+ return ContentsOrErr.takeError();
+ ArrayRef<uint8_t> Content = *ContentsOrErr;
+ DataExtractor Data(Content, this->isLE(), ELFT::Is64Bits ? 8 : 4);
+ std::vector<FuncMap> FunctionEntries;
+
+ DataExtractor::Cursor Cur(0);
+
+ // Helper lampda to extract the (possiblly relocatable) address stored at
Cur.
+ auto ExtractAddress = [&]() -> Expected<typename ELFFile<ELFT>::uintX_t> {
+ uint64_t RelocationOffsetInSection = Cur.tell();
+ auto Address =
+ static_cast<typename ELFFile<ELFT>::uintX_t>(Data.getAddress(Cur));
+ if (!Cur)
+ return Cur.takeError();
+ if (!IsRelocatable)
+ return Address;
+ assert(Address == 0);
+ Expected<unsigned> AddressOrErr =
+ GetAddressForRelocation(RelocationOffsetInSection);
+ if (!AddressOrErr)
+ return AddressOrErr.takeError();
+ return *AddressOrErr;
+ };
+
+ uint8_t Version = 0;
+ while (Cur && Cur.tell() < Content.size()) {
+ if (Sec.sh_type == ELF::SHT_LLVM_FUNC_MAP) {
----------------
jh7370 wrote:
Why is this check needed?
https://github.com/llvm/llvm-project/pull/124333
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