This patch improves the MCJIT runtime dynamic loader by adding new handling

of zero-initialized sections, virtual sections and common symbols
and preventing the loading of sections which are not required for
execution such as debug information.

Patch by Andy Kaylor!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154610 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Preston Gurd
2012-04-12 20:13:57 +00:00
parent f0bcecc0d5
commit c68dda815e
28 changed files with 319 additions and 80 deletions

View File

@ -33,6 +33,15 @@
namespace llvm {
namespace object {
// Subclasses of ELFObjectFile may need this for template instantiation
inline std::pair<unsigned char, unsigned char>
getElfArchType(MemoryBuffer *Object) {
if (Object->getBufferSize() < ELF::EI_NIDENT)
return std::make_pair((uint8_t)ELF::ELFCLASSNONE,(uint8_t)ELF::ELFDATANONE);
return std::make_pair( (uint8_t)Object->getBufferStart()[ELF::EI_CLASS]
, (uint8_t)Object->getBufferStart()[ELF::EI_DATA]);
}
// Templates to choose Elf_Addr and Elf_Off depending on is64Bits.
template<support::endianness target_endianness>
struct ELFDataTypeTypedefHelperCommon {
@ -540,6 +549,10 @@ protected:
virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const;
virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const;
virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const;
virtual error_code isSectionRequiredForExecution(DataRefImpl Sec,
bool &Res) const;
virtual error_code isSectionVirtual(DataRefImpl Sec, bool &Res) const;
virtual error_code isSectionZeroInit(DataRefImpl Sec, bool &Res) const;
virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
bool &Result) const;
virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const;
@ -1092,6 +1105,43 @@ error_code ELFObjectFile<target_endianness, is64Bits>
return object_error::success;
}
template<support::endianness target_endianness, bool is64Bits>
error_code ELFObjectFile<target_endianness, is64Bits>
::isSectionRequiredForExecution(DataRefImpl Sec,
bool &Result) const {
const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
if (sec->sh_flags & ELF::SHF_ALLOC)
Result = true;
else
Result = false;
return object_error::success;
}
template<support::endianness target_endianness, bool is64Bits>
error_code ELFObjectFile<target_endianness, is64Bits>
::isSectionVirtual(DataRefImpl Sec,
bool &Result) const {
const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
if (sec->sh_type == ELF::SHT_NOBITS)
Result = true;
else
Result = false;
return object_error::success;
}
template<support::endianness target_endianness, bool is64Bits>
error_code ELFObjectFile<target_endianness, is64Bits>::isSectionZeroInit(DataRefImpl Sec,
bool &Result) const {
const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p);
// For ELF, all zero-init sections are virtual (that is, they occupy no space
// in the object image) and vice versa.
if (sec->sh_flags & ELF::SHT_NOBITS)
Result = true;
else
Result = false;
return object_error::success;
}
template<support::endianness target_endianness, bool is64Bits>
error_code ELFObjectFile<target_endianness, is64Bits>
::sectionContainsSymbol(DataRefImpl Sec,