[llvm] r234839 - [RuntimeDyldELF] Improve GOT support
Lang Hames
lhames at gmail.com
Wed Apr 15 09:41:16 PDT 2015
Hi Keno,
I think RuntimeDyldMachO and RuntimeDyldCOFF are safe in this respect - they shouldn't be accessing the object at all after loadObject returns.
When I removed object file ownership from RuntimeDyld I tried to make sure that RuntimeDyldELF held an internal copy of the object (which it needed for debugging anyway), and always referred back to that. Your new fix is a much better solution though. I'll sanity check when I get in to the office, and I look forward to seeing it in tree. :)
Cheers,
Lang.
Sent from my iPad
> On Apr 14, 2015, at 11:34 PM, Keno Fischer <kfischer at college.harvard.edu> wrote:
>
> Hi Lang,
>
> I have debugged this after getting MSVC setup in a virtual machine and it looks like the object file is getting freed before the relocations are applied. Unfortunately, on ELF, we still have the placeholder mechanism looking at the original object file, so I suspect this is a use-after-free even on other platforms, though we are getting lucky there. I suspect this was a problem even without my patch and it's just getting exposed here. How does the object file get freed? Is there some way to prevent this?
>
> Keno
>
>> On Tue, Apr 14, 2015 at 1:16 PM, Lang Hames <lhames at gmail.com> wrote:
>> Looks like SectionEntry was holding the section name as a StringRef. That's not safe now that we can delete the ObjectFile after loading.
>>
>> I've fixed this in r234910. Hopefully you can get more sane output from the test-case now.
>>
>> - Lang.
>>
>>> On Tue, Apr 14, 2015 at 8:12 AM, Keno Fischer <kfischer at college.harvard.edu> wrote:
>>> This is missing the second .got section, I believe (hard to tell with the corrupted names of course). Did llvm-rtdyld get built correctly? Also CC Lang for why those would be corrupted.
>>>
>>>> On Tue, Apr 14, 2015 at 10:51 AM, Kuperstein, Michael M <michael.m.kuperstein at intel.com> wrote:
>>>> Parse symbols:
>>>>
>>>> emitSection SectionID: 0 Name: .text obj addr: 0000000000BA93C0 new addr: 0000000000080000 DataSize: 10 StubBufSize: 6 Allocate: 16
>>>>
>>>> Type: 4 Name: foo SID: 0 Offset: 0000000000000000 flags: 0
>>>>
>>>> Parse relocations:
>>>>
>>>> SectionID: 0
>>>>
>>>> RelType: 9 Addend: -4 TargetName: G
>>>>
>>>> SectionID: 0 Offset: 3
>>>>
>>>> Parse symbols:
>>>>
>>>> emitSection SectionID: 2 Name: .bss obj addr: 0000000000000000 new addr: 0000000000AA0000 DataSize: 1 StubBufSize: 0 Allocate: 1
>>>>
>>>> Type: 1 Name: F SID: 2 Offset: 0000000000000000 flags: 66
>>>>
>>>> emitSection SectionID: 3 Name: .data.rel obj addr: 0000000000BA93D0 new addr: 0000000000AB0000 DataSize: 8 StubBufSize: 6 Allocate: 14
>>>>
>>>> Type: 1 Name: G SID: 3 Offset: 0000000000000000 flags: 66
>>>>
>>>> Parse relocations:
>>>>
>>>> SectionID: 3
>>>>
>>>> RelType: 1 Addend: 0 TargetName: F
>>>>
>>>> SectionID: 3 Offset: 0
>>>>
>>>> Reassigning address for section 0 (▌▌▌▌▌): 0x0000000000080000 -> 0x0000000000001000
>>>>
>>>> Reassigning address for section 1 (.got): 0x0000000000090000 -> 0x0000000000011000
>>>>
>>>> Reassigning address for section 2 (▌▌▌▌): 0x0000000000aa0000 -> 0x0000000000021000
>>>>
>>>> Reassigning address for section 3 (▌▌▌▌▌▌▌▌▌): 0x0000000000ab0000 -> 0x0000000000031000
>>>>
>>>> Resolving relocations Name: G 0x31000
>>>>
>>>> Writing 0000000000031000 at 0000000000090000
>>>>
>>>> Resolving relocations Section #0 0000000000001000
>>>>
>>>> ----- Contents of section ▌▌▌▌▌ before relocations -----
>>>>
>>>> 0x0000000000001000: 48 8b 05 00 00 00 00 8b 00 c3
>>>>
>>>> ----- Contents of section ▌▌▌▌▌ after relocations -----
>>>>
>>>> 0x0000000000001000: 48 8b 05 00 00 00 00 8b 00 c3
>>>>
>>>> Resolving relocations Section #1 0000000000011000
>>>>
>>>> ----- Contents of section .got before relocations -----
>>>>
>>>> 0x0000000000011000: 00 10 03 00 00 00 00 00
>>>>
>>>> Assertion failed: RealOffset <= INT32_MAX && RealOffset >= INT32_MIN, file ..\..\..\..\lib\ExecutionEngine\RuntimeDyld\RuntimeDyldELF.cpp, line 259
>>>>
>>>>
>>>>
>>>> (The section names are originally printed that way, it’s not the mail client’s fault)
>>>>
>>>>
>>>>
>>>> Michael
>>>>
>>>>
>>>>
>>>> From: Keno Fischer [mailto:kfischer at college.harvard.edu]
>>>> Sent: Tuesday, April 14, 2015 17:18
>>>> To: Kuperstein, Michael M
>>>> Cc: llvm-commits at cs.uiuc.edu
>>>> Subject: Re: [llvm] r234839 - [RuntimeDyldELF] Improve GOT support
>>>>
>>>>
>>>>
>>>> Thanks Michael. I didn't realize that flag was being added on windows, but I guess it makes sense, since you're using a non-standard triple for MCJIT. I see this was reverted already.
>>>>
>>>>
>>>>
>>>> Regarding the other failure, that's really odd, because this is precisely the failure that this commit is supposed to solve. Can you send the output of that invocation with `-debug-only dyld` added at the end?
>>>>
>>>>
>>>>
>>>> On Tue, Apr 14, 2015 at 5:57 AM, Kuperstein, Michael M <michael.m.kuperstein at intel.com> wrote:
>>>>
>>>> Hello Keno,
>>>>
>>>> Unfortunately, cross-module-sm-pic-a.ll now breaks on windows.
>>>>
>>>> It looks like %lli provides a triple, so this:
>>>> %lli -mtriple=x86_64-pc-linux -extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic -code-model=small %s > /dev/null
>>>>
>>>> Becomes:
>>>> lli.EXE -mtriple=x86_64-pc-win32-elf -mtriple=x86_64-pc-linux -extra-module=...
>>>>
>>>> Which (rightfully) gets rejected by lli.
>>>>
>>>> Thanks,
>>>> Michael
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Keno Fischer
>>>> Sent: Tuesday, April 14, 2015 05:11
>>>> To: llvm-commits at cs.uiuc.edu
>>>> Subject: [llvm] r234839 - [RuntimeDyldELF] Improve GOT support
>>>>
>>>> Author: kfischer
>>>> Date: Mon Apr 13 21:10:35 2015
>>>> New Revision: 234839
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=234839&view=rev
>>>> Log:
>>>> [RuntimeDyldELF] Improve GOT support
>>>>
>>>> Summary:
>>>> This is the first in a series of patches to eventually add support for TLS relocations to RuntimeDyld. This patch resolves an issue in the current GOT handling, where GOT entries would be reused between object files, which leads to the same situation that necessitates the GOT in the first place, i.e. that the 32-bit offset can not cover all of the address space. Thus this patch makes the GOT object-file-local.
>>>> Unfortunately, this still isn't quite enough, because the MemoryManager does not yet guarantee that sections are allocated sufficiently close to each other, even if they belong to the same object file. To address this concern, this patch also adds a small API abstraction on top of the GOT allocation mechanism that will allow (temporarily, until the MemoryManager is improved) using the stub mechanism instead of allocating a different section. The actual switch from separate section to stub mechanism will be part of a follow-on commit, so that it can be easily reverted independently at the appropriate time.
>>>>
>>>> Test Plan: Includes a test case where the GOT of two object files is artificially forced to be apart by several GB.
>>>>
>>>> Reviewers: lhames
>>>>
>>>> Reviewed By: lhames
>>>>
>>>> Subscribers: llvm-commits
>>>>
>>>> Differential Revision: http://reviews.llvm.org/D8813
>>>>
>>>> Added:
>>>> llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/ELF_x64-64_PIC_relocations.s
>>>> llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/
>>>> llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ExternalGlobal.ll
>>>> Modified:
>>>> llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
>>>> llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCheckerImpl.h
>>>> llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
>>>> llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
>>>> llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
>>>> llvm/trunk/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp Mon Apr
>>>>
>>>> +++ 13 21:10:35 2015
>>>> @@ -814,7 +814,6 @@ void RuntimeDyldImpl::resolveExternalSym
>>>> report_fatal_error("Program used external function '" + Name +
>>>> "' which could not be resolved!");
>>>>
>>>> - updateGOTEntries(Name, Addr);
>>>> DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
>>>> << format("0x%lx", Addr) << "\n");
>>>> // This list may have been updated when we called getSymbolAddress, so
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCheckerImpl.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCheckerImpl.h?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCheckerImpl.h (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCheckerImpl.h
>>>> +++ Mon Apr 13 21:10:35 2015
>>>> @@ -19,6 +19,7 @@ class RuntimeDyldCheckerImpl {
>>>> friend class RuntimeDyldChecker;
>>>> friend class RuntimeDyldImpl;
>>>> friend class RuntimeDyldCheckerExprEval;
>>>> + friend class RuntimeDyldELF;
>>>>
>>>> public:
>>>> RuntimeDyldCheckerImpl(RuntimeDyld &RTDyld, MCDisassembler *Disassembler,
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp Mon
>>>> +++ Apr 13 21:10:35 2015
>>>>
>>>> @@ -12,6 +12,7 @@
>>>> //===----------------------------------------------------------------------===//
>>>>
>>>> #include "RuntimeDyldELF.h"
>>>> +#include "RuntimeDyldCheckerImpl.h"
>>>> #include "llvm/ADT/IntervalMap.h"
>>>> #include "llvm/ADT/STLExtras.h"
>>>> #include "llvm/ADT/StringRef.h"
>>>> @@ -185,7 +186,7 @@ namespace llvm {
>>>>
>>>> RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
>>>> RuntimeDyld::SymbolResolver &Resolver)
>>>> - : RuntimeDyldImpl(MemMgr, Resolver) {}
>>>> + : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0),
>>>> + CurrentGOTIndex(0) {}
>>>> RuntimeDyldELF::~RuntimeDyldELF() {}
>>>>
>>>> void RuntimeDyldELF::registerEHFrames() { @@ -245,27 +246,16 @@ void RuntimeDyldELF::resolveX86_64Reloca
>>>> << format("%p\n", Section.Address + Offset));
>>>> break;
>>>> }
>>>> - case ELF::R_X86_64_GOTPCREL: {
>>>> - // findGOTEntry returns the 'G + GOT' part of the relocation calculation
>>>> - // based on the load/target address of the GOT (not the current/local addr).
>>>> - uint64_t GOTAddr = findGOTEntry(Value, SymOffset);
>>>> - uint64_t FinalAddress = Section.LoadAddress + Offset;
>>>> - // The processRelocationRef method combines the symbol offset and the addend
>>>> - // and in most cases that's what we want. For this relocation type, we need
>>>> - // the raw addend, so we subtract the symbol offset to get it.
>>>> - int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress;
>>>> - assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
>>>> - int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
>>>> - support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset;
>>>> - break;
>>>> - }
>>>> case ELF::R_X86_64_PC32: {
>>>> // Get the placeholder value from the generated object since
>>>> // a previous relocation attempt may have overwritten the loaded version
>>>> support::ulittle32_t::ref Placeholder(
>>>> (void *)(Section.ObjAddress + Offset));
>>>> uint64_t FinalAddress = Section.LoadAddress + Offset;
>>>> - int64_t RealOffset = Placeholder + Value + Addend - FinalAddress;
>>>> + int64_t RealOffset = Value + Addend - FinalAddress;
>>>> + // Don't add the placeholder if this is a stub
>>>> + if (Offset < Section.Size)
>>>> + RealOffset += Placeholder;
>>>> assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
>>>> int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
>>>> support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset; @@ -277,8 +267,10 @@ void RuntimeDyldELF::resolveX86_64Reloca
>>>> support::ulittle64_t::ref Placeholder(
>>>> (void *)(Section.ObjAddress + Offset));
>>>> uint64_t FinalAddress = Section.LoadAddress + Offset;
>>>> - support::ulittle64_t::ref(Section.Address + Offset) =
>>>> - Placeholder + Value + Addend - FinalAddress;
>>>> + int64_t RealOffset = Value + Addend - FinalAddress;
>>>> + if (Offset < Section.Size)
>>>> + RealOffset += Placeholder;
>>>> + support::ulittle64_t::ref(Section.Address + Offset) = RealOffset;
>>>> break;
>>>> }
>>>> }
>>>> @@ -1323,16 +1315,18 @@ relocation_iterator RuntimeDyldELF::proc
>>>> Stubs[Value] = StubOffset;
>>>> createStubFunction((uint8_t *)StubAddress);
>>>>
>>>> - // Create a GOT entry for the external function.
>>>> - GOTEntries.push_back(Value);
>>>> -
>>>> - // Make our stub function a relative call to the GOT entry.
>>>> - RelocationEntry RE(SectionID, StubOffset + 2, ELF::R_X86_64_GOTPCREL,
>>>> - -4);
>>>> - addRelocationForSymbol(RE, Value.SymbolName);
>>>> -
>>>> // Bump our stub offset counter
>>>> Section.StubOffset = StubOffset + getMaxStubSize();
>>>> +
>>>> + // Allocate a GOT Entry
>>>> + uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
>>>> +
>>>> + // The load of the GOT address has an addend of -4
>>>> + resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset
>>>> + - 4);
>>>> +
>>>> + // Fill in the value of the symbol we're targeting into the GOT
>>>> + addRelocationForSymbol(computeGOTOffsetRE(SectionID,GOTOffset,0,ELF::R_X86_64_64),
>>>> + Value.SymbolName);
>>>> }
>>>>
>>>> // Make the target call a call into the stub table.
>>>> @@ -1343,10 +1337,17 @@ relocation_iterator RuntimeDyldELF::proc
>>>> Value.Offset);
>>>> addRelocationForSection(RE, Value.SectionID);
>>>> }
>>>> + } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) {
>>>> + uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
>>>> + resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend);
>>>> +
>>>> + // Fill in the value of the symbol we're targeting into the GOT
>>>> + RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64);
>>>> + if (Value.SymbolName)
>>>> + addRelocationForSymbol(RE, Value.SymbolName);
>>>> + else
>>>> + addRelocationForSection(RE, Value.SectionID);
>>>> } else {
>>>> - if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) {
>>>> - GOTEntries.push_back(Value);
>>>> - }
>>>> RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
>>>> if (Value.SymbolName)
>>>> addRelocationForSymbol(RE, Value.SymbolName); @@ -1356,22 +1357,6 @@ relocation_iterator RuntimeDyldELF::proc
>>>> return ++RelI;
>>>> }
>>>>
>>>> -void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) {
>>>> -
>>>> - SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator it;
>>>> - SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator end = GOTs.end();
>>>> -
>>>> - for (it = GOTs.begin(); it != end; ++it) {
>>>> - GOTRelocations &GOTEntries = it->second;
>>>> - for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
>>>> - if (GOTEntries[i].SymbolName != nullptr &&
>>>> - GOTEntries[i].SymbolName == Name) {
>>>> - GOTEntries[i].Offset = Addr;
>>>> - }
>>>> - }
>>>> - }
>>>> -}
>>>> -
>>>> size_t RuntimeDyldELF::getGOTEntrySize() {
>>>> // We don't use the GOT in all of these cases, but it's essentially free
>>>> // to put them all here.
>>>> @@ -1398,75 +1383,50 @@ size_t RuntimeDyldELF::getGOTEntrySize()
>>>> return Result;
>>>> }
>>>>
>>>> -uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress, uint64_t Offset) {
>>>> -
>>>> - const size_t GOTEntrySize = getGOTEntrySize();
>>>> -
>>>> - SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator it;
>>>> - SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator end =
>>>> - GOTs.end();
>>>> -
>>>> - int GOTIndex = -1;
>>>> - for (it = GOTs.begin(); it != end; ++it) {
>>>> - SID GOTSectionID = it->first;
>>>> - const GOTRelocations &GOTEntries = it->second;
>>>> -
>>>> - // Find the matching entry in our vector.
>>>> - uint64_t SymbolOffset = 0;
>>>> - for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
>>>> - if (!GOTEntries[i].SymbolName) {
>>>> - if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress &&
>>>> - GOTEntries[i].Offset == Offset) {
>>>> - GOTIndex = i;
>>>> - SymbolOffset = GOTEntries[i].Offset;
>>>> - break;
>>>> - }
>>>> - } else {
>>>> - // GOT entries for external symbols use the addend as the address when
>>>> - // the external symbol has been resolved.
>>>> - if (GOTEntries[i].Offset == LoadAddress) {
>>>> - GOTIndex = i;
>>>> - // Don't use the Addend here. The relocation handler will use it.
>>>> - break;
>>>> - }
>>>> - }
>>>> - }
>>>> -
>>>> - if (GOTIndex != -1) {
>>>> - if (GOTEntrySize == sizeof(uint64_t)) {
>>>> - uint64_t *LocalGOTAddr = (uint64_t *)getSectionAddress(GOTSectionID);
>>>> - // Fill in this entry with the address of the symbol being referenced.
>>>> - LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset;
>>>> - } else {
>>>> - uint32_t *LocalGOTAddr = (uint32_t *)getSectionAddress(GOTSectionID);
>>>> - // Fill in this entry with the address of the symbol being referenced.
>>>> - LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset);
>>>> - }
>>>> -
>>>> - // Calculate the load address of this entry
>>>> - return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize);
>>>> - }
>>>> - }
>>>> -
>>>> - assert(GOTIndex != -1 && "Unable to find requested GOT entry.");
>>>> - return 0;
>>>> +uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID,
>>>>
>>>> +unsigned no) {
>>>> + (void)SectionID; // The GOT Section is the same for all section in
>>>> +the object file
>>>> + if (GOTSectionID == 0) {
>>>> + GOTSectionID = Sections.size();
>>>> + // Reserve a section id. We'll allocate the section later
>>>> + // once we know the total size
>>>> + Sections.push_back(SectionEntry(".got", 0, 0, 0));
>>>> + }
>>>> + uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
>>>> + CurrentGOTIndex += no;
>>>> + return StartOffset;
>>>> +}
>>>> +
>>>> +void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID,
>>>> +uint64_t Offset, uint64_t GOTOffset) {
>>>> + // Fill in the relative address of the GOT Entry into the stub
>>>> + RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32,
>>>> +GOTOffset);
>>>> + addRelocationForSection(GOTRE, GOTSectionID); }
>>>> +
>>>> +RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset,
>>>> + uint32_t Type) {
>>>> + (void)SectionID; // The GOT Section is the same for all section in
>>>> +the object file
>>>>
>>>> + return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
>>>> }
>>>>
>>>> void RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj,
>>>> ObjSectionToIDMap &SectionMap) {
>>>> // If necessary, allocate the global offset table
>>>> - size_t numGOTEntries = GOTEntries.size();
>>>> - if (numGOTEntries != 0) {
>>>> + if (GOTSectionID != 0) {
>>>> // Allocate memory for the section
>>>> - unsigned SectionID = Sections.size();
>>>> - size_t TotalSize = numGOTEntries * getGOTEntrySize();
>>>> + size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
>>>> uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
>>>> - SectionID, ".got", false);
>>>> + GOTSectionID, ".got",
>>>> + false);
>>>> if (!Addr)
>>>> report_fatal_error("Unable to allocate memory for GOT!");
>>>>
>>>> - GOTs.push_back(std::make_pair(SectionID, GOTEntries));
>>>> - Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0));
>>>> + Sections[GOTSectionID] = SectionEntry(".got", Addr, TotalSize, 0);
>>>> +
>>>> + if (Checker)
>>>> + Checker->registerSection(Obj.getFileName(), GOTSectionID);
>>>> +
>>>> // For now, initialize all GOT entries to zero. We'll fill them in as
>>>> // needed when GOT-based relocations are applied.
>>>> memset(Addr, 0, TotalSize);
>>>> @@ -1483,6 +1443,9 @@ void RuntimeDyldELF::finalizeLoad(const
>>>> break;
>>>> }
>>>> }
>>>> +
>>>> + GOTSectionID = 0;
>>>> + CurrentGOTIndex = 0;
>>>> }
>>>>
>>>> bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const {
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h Mon Apr
>>>>
>>>> +++ 13 21:10:35 2015
>>>> @@ -80,16 +80,32 @@ class RuntimeDyldELF : public RuntimeDyl
>>>> ObjSectionToIDMap &LocalSections,
>>>> RelocationValueRef &Rel);
>>>>
>>>> - uint64_t findGOTEntry(uint64_t LoadAddr, uint64_t Offset);
>>>> size_t getGOTEntrySize();
>>>>
>>>> - void updateGOTEntries(StringRef Name, uint64_t Addr) override;
>>>> + SectionEntry &getSection(unsigned SectionID) { return
>>>> + Sections[SectionID]; }
>>>>
>>>> - // Relocation entries for symbols whose position-independent offset is
>>>> - // updated in a global offset table.
>>>> - typedef SmallVector<RelocationValueRef, 2> GOTRelocations;
>>>> - GOTRelocations GOTEntries; // List of entries requiring finalization.
>>>> - SmallVector<std::pair<SID, GOTRelocations>, 8> GOTs; // Allocated tables.
>>>> + // Allocate no GOT entries for use in the given section.
>>>> + uint64_t allocateGOTEntries(unsigned SectionID, unsigned no);
>>>> +
>>>> + // Resolve the relvative address of GOTOffset in Section ID and place
>>>> + // it at the given Offset void resolveGOTOffsetRelocation(unsigned
>>>> + SectionID, uint64_t Offset,
>>>> + uint64_t GOTOffset);
>>>> +
>>>> + // For a GOT entry referenced from SectionID, compute a relocation
>>>> + entry // that will place the final resolved value in the GOT slot
>>>> + RelocationEntry computeGOTOffsetRE(unsigned SectionID,
>>>> + uint64_t GOTOffset,
>>>> + uint64_t SymbolOffset,
>>>> + unsigned Type);
>>>> +
>>>> + // The tentative ID for the GOT section unsigned GOTSectionID;
>>>> +
>>>> + // Records the current number of allocated slots in the GOT // (This
>>>> + would be equivalent to GOTEntries.size() were it not for relocations
>>>> + // that consume more than one slot) unsigned CurrentGOTIndex;
>>>>
>>>> // When a module is loaded we save the SectionID of the EH frame section
>>>> // in a table until we receive a request to register all unregistered
>>>>
>>>> Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h (original)
>>>> +++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h Mon Apr
>>>> +++ 13 21:10:35 2015
>>>> @@ -361,10 +361,6 @@ protected:
>>>> /// \brief Resolve relocations to external symbols.
>>>> void resolveExternalSymbols();
>>>>
>>>> - /// \brief Update GOT entries for external symbols.
>>>> - // The base class does nothing. ELF overrides this.
>>>> - virtual void updateGOTEntries(StringRef Name, uint64_t Addr) {}
>>>> -
>>>> // \brief Compute an upper bound of the memory that is required to load all
>>>> // sections
>>>> void computeTotalAllocSize(const ObjectFile &Obj, uint64_t &CodeSize,
>>>>
>>>> Modified: llvm/trunk/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll?rev=234839&r1=234838&r2=234839&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll (original)
>>>> +++ llvm/trunk/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll Mon
>>>> +++ Apr 13 21:10:35 2015
>>>> @@ -1,4 +1,5 @@
>>>> ; RUN: %lli -extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic -code-model=small %s > /dev/null
>>>> +; RUN: %lli -mtriple=x86_64-pc-linux
>>>> +-extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic
>>>> +-code-model=small %s > /dev/null
>>>> ; XFAIL: mips, i686, i386
>>>>
>>>> declare i32 @FB()
>>>>
>>>> Added: llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/ELF_x64-64_PIC_relocations.s
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/ELF_x64-64_PIC_relocations.s?rev=234839&view=auto
>>>> ==============================================================================
>>>> --- llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/ELF_x64-64_PIC_relocations.s (added)
>>>> +++ llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/ELF_x64-64_PIC_reloc
>>>> +++ ations.s Mon Apr 13 21:10:35 2015
>>>> @@ -0,0 +1,31 @@
>>>> +# RUN: llvm-mc -triple=x86_64-pc-linux -relocation-model=pic
>>>> +-filetype=obj -o %T/test_ELF1_x86-64.o %s # RUN: llvm-mc
>>>> +-triple=x86_64-pc-linux -relocation-model=pic -filetype=obj -o
>>>> +%T/test_ELF2_x86-64.o %s # RUN: llc -mtriple=x86_64-pc-linux
>>>> +-relocation-model=pic -filetype=obj -o
>>>> +%T/test_ELF_ExternalGlobal_x86-64.o %S/Inputs/ExternalGlobal.ll # RUN:
>>>> +llvm-rtdyld -triple=x86_64-pc-linux -verify %T/test_ELF1_x86-64.o
>>>> +%T/test_ELF_ExternalGlobal_x86-64.o
>>>> +# Test that we can load this code twice at memory locations more than
>>>> +2GB apart # RUN: llvm-rtdyld -triple=x86_64-pc-linux -verify
>>>> +-map-section test_ELF1_x86-64.o,.got=0x10000 -map-section
>>>> +test_ELF2_x86-64.o,.text=0x100000000 -map-section
>>>> +test_ELF2_x86-64.o,.got=0x100010000 %T/test_ELF1_x86-64.o
>>>> +%T/test_ELF2_x86-64.o %T/test_ELF_ExternalGlobal_x86-64.o
>>>>
>>>> +
>>>> +# Assembly obtained by compiling the following and adding checks:
>>>> +# @G = external global i8*
>>>> +#
>>>> +# define i8* @foo() {
>>>> +# %ret = load i8** @G
>>>> +# ret i32 %ret
>>>> +# }
>>>> +#
>>>> +
>>>> +#
>>>> + .text
>>>> + .file "ELF_x64-64_PIC_relocations.ll"
>>>> + .align 16, 0x90
>>>> + .type foo, at function
>>>> +foo: # @foo
>>>> +# BB#0:
>>>> + movq G at GOTPCREL(%rip), %rax
>>>> + movl (%rax), %eax
>>>> + retq
>>>> +.Ltmp0:
>>>> + .size foo, .Ltmp0-foo
>>>> +
>>>> +
>>>> + .section ".note.GNU-stack","", at progbits
>>>>
>>>> Added: llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ExternalGlobal.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ExternalGlobal.ll?rev=234839&view=auto
>>>> ==============================================================================
>>>> --- llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ExternalGlobal.ll (added)
>>>> +++ llvm/trunk/test/ExecutionEngine/RuntimeDyld/X86/Inputs/ExternalGloba
>>>>
>>>> +++ l.ll Mon Apr 13 21:10:35 2015
>>>> @@ -0,0 +1,2 @@
>>>> + at F = global i8 0
>>>> + at G = global i8* @F
>>>>
>>>>
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