From: Lang Hames Date: Sat, 4 Jul 2015 01:35:26 +0000 (+0000) Subject: [RuntimeDyld] Skip relocations for external symbols with 64-bit address ~0ULL. X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=b21c7647d8dc16e3dc9f3781d2b5bc6faf42e75e;hp=9a9ee6f550c0789053c260203aea8430a34554fe [RuntimeDyld] Skip relocations for external symbols with 64-bit address ~0ULL. Requested by Eugene Rozenfeld of the LLILC team, this feature allows JIT clients to skip relocations for selected external symbols by returning ~0ULL from their symbol resolver. If this value is returned for a given symbol, RuntimeDyld will skip all relocations for that symbol. The client will be responsible for applying the skipped relocations manually before the code is executed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241383 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp index 092c696d53e..6851625b9e9 100644 --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp @@ -815,12 +815,16 @@ void RuntimeDyldImpl::resolveExternalSymbols() { report_fatal_error("Program used external function '" + Name + "' which could not be resolved!"); - DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t" - << format("0x%lx", Addr) << "\n"); - // This list may have been updated when we called getSymbolAddress, so - // don't change this code to get the list earlier. - RelocationList &Relocs = i->second; - resolveRelocationList(Relocs, Addr); + // If Resolver returned UINT64_MAX, the client wants to handle this symbol + // manually and we shouldn't resolve its relocations. + if (Addr != UINT64_MAX) { + DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t" + << format("0x%lx", Addr) << "\n"); + // This list may have been updated when we called getSymbolAddress, so + // don't change this code to get the list earlier. + RelocationList &Relocs = i->second; + resolveRelocationList(Relocs, Addr); + } } ExternalSymbolRelocations.erase(i); diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp index 957571b092d..ae199b72022 100644 --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp @@ -727,7 +727,9 @@ bool RuntimeDyldCheckerImpl::checkAllRulesInBuffer(StringRef RulePrefix, } bool RuntimeDyldCheckerImpl::isSymbolValid(StringRef Symbol) const { - return getRTDyld().getSymbolLocalAddress(Symbol) != nullptr; + if (getRTDyld().getSymbolLocalAddress(Symbol)) + return true; + return !!getRTDyld().Resolver.findSymbol(Symbol); } uint64_t RuntimeDyldCheckerImpl::getSymbolLocalAddr(StringRef Symbol) const { diff --git a/test/ExecutionEngine/RuntimeDyld/X86/MachO_x86-64_PIC_relocations.s b/test/ExecutionEngine/RuntimeDyld/X86/MachO_x86-64_PIC_relocations.s index f28e4d24599..2ef8cc439df 100644 --- a/test/ExecutionEngine/RuntimeDyld/X86/MachO_x86-64_PIC_relocations.s +++ b/test/ExecutionEngine/RuntimeDyld/X86/MachO_x86-64_PIC_relocations.s @@ -1,5 +1,5 @@ # RUN: llvm-mc -triple=x86_64-apple-macosx10.9 -relocation-model=pic -filetype=obj -o %T/test_x86-64.o %s -# RUN: llvm-rtdyld -triple=x86_64-apple-macosx10.9 -verify -check=%s %/T/test_x86-64.o +# RUN: llvm-rtdyld -triple=x86_64-apple-macosx10.9 -dummy-extern ds1=0xfffffffffffffffe -dummy-extern ds2=0xffffffffffffffff -verify -check=%s %/T/test_x86-64.o .section __TEXT,__text,regular,pure_instructions .globl foo @@ -46,4 +46,15 @@ eh_frame_test: x: .long 5 +# Test dummy-extern relocation. +# rtdyld-check: *{8}z1 = ds1 +z1: + .quad ds1 + +# Test external-symbol relocation bypass: symbols with addr 0xffffffffffffffff +# don't have their relocations applied. +# rtdyld-check: *{8}z2 = 0 +z2: + .quad ds2 + .subsections_via_symbols diff --git a/tools/llvm-rtdyld/llvm-rtdyld.cpp b/tools/llvm-rtdyld/llvm-rtdyld.cpp index 50eb87ab934..86f66f89b15 100644 --- a/tools/llvm-rtdyld/llvm-rtdyld.cpp +++ b/tools/llvm-rtdyld/llvm-rtdyld.cpp @@ -115,8 +115,17 @@ TargetSectionSep("target-section-sep", static cl::list SpecificSectionMappings("map-section", - cl::desc("Map a section to a specific address."), - cl::ZeroOrMore); + cl::desc("For -verify only: Map a section to a " + "specific address."), + cl::ZeroOrMore, + cl::Hidden); + +static cl::list +DummySymbolMappings("dummy-extern", + cl::desc("For -verify only: Inject a symbol into the extern " + "symbol table."), + cl::ZeroOrMore, + cl::Hidden); /* *** */ @@ -147,10 +156,25 @@ public: // relocations) will get to the data cache but not to the instruction cache. virtual void invalidateInstructionCache(); + void addDummySymbol(const std::string &Name, uint64_t Addr) { + DummyExterns[Name] = Addr; + } + + RuntimeDyld::SymbolInfo findSymbol(const std::string &Name) override { + auto I = DummyExterns.find(Name); + + if (I != DummyExterns.end()) + return RuntimeDyld::SymbolInfo(I->second, JITSymbolFlags::Exported); + + return RTDyldMemoryManager::findSymbol(Name); + } + void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size) override {} void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size) override {} +private: + std::map DummyExterns; }; uint8_t *TrivialMemoryManager::allocateCodeSection(uintptr_t Size, @@ -401,7 +425,7 @@ applySpecificSectionMappings(RuntimeDyldChecker &Checker) { for (StringRef Mapping : SpecificSectionMappings) { size_t EqualsIdx = Mapping.find_first_of("="); - StringRef SectionIDStr = Mapping.substr(0, EqualsIdx); + std::string SectionIDStr = Mapping.substr(0, EqualsIdx); size_t ComaIdx = Mapping.find_first_of(","); if (ComaIdx == StringRef::npos) { @@ -410,8 +434,8 @@ applySpecificSectionMappings(RuntimeDyldChecker &Checker) { exit(1); } - StringRef FileName = SectionIDStr.substr(0, ComaIdx); - StringRef SectionName = SectionIDStr.substr(ComaIdx + 1); + std::string FileName = SectionIDStr.substr(0, ComaIdx); + std::string SectionName = SectionIDStr.substr(ComaIdx + 1); uint64_t OldAddrInt; std::string ErrorMsg; @@ -425,11 +449,11 @@ applySpecificSectionMappings(RuntimeDyldChecker &Checker) { void* OldAddr = reinterpret_cast(static_cast(OldAddrInt)); - StringRef NewAddrStr = Mapping.substr(EqualsIdx + 1); + std::string NewAddrStr = Mapping.substr(EqualsIdx + 1); uint64_t NewAddr; - if (NewAddrStr.getAsInteger(0, NewAddr)) { - errs() << "Invalid section address in mapping: " << Mapping << "\n"; + if (StringRef(NewAddrStr).getAsInteger(0, NewAddr)) { + errs() << "Invalid section address in mapping '" << Mapping << "'.\n"; exit(1); } @@ -451,9 +475,9 @@ applySpecificSectionMappings(RuntimeDyldChecker &Checker) { // Defaults to zero. Set to something big // (e.g. 1 << 32) to stress-test stubs, GOTs, etc. // -static void remapSections(const llvm::Triple &TargetTriple, - const TrivialMemoryManager &MemMgr, - RuntimeDyldChecker &Checker) { +static void remapSectionsAndSymbols(const llvm::Triple &TargetTriple, + TrivialMemoryManager &MemMgr, + RuntimeDyldChecker &Checker) { // Set up a work list (section addr/size pairs). typedef std::list> WorklistT; @@ -516,6 +540,27 @@ static void remapSections(const llvm::Triple &TargetTriple, Checker.getRTDyld().mapSectionAddress(CurEntry.first, NextSectionAddr); } + // Add dummy symbols to the memory manager. + for (const auto &Mapping : DummySymbolMappings) { + size_t EqualsIdx = Mapping.find_first_of("="); + + if (EqualsIdx == StringRef::npos) { + errs() << "Invalid dummy symbol specification '" << Mapping + << "'. Should be '='\n"; + exit(1); + } + + std::string Symbol = Mapping.substr(0, EqualsIdx); + std::string AddrStr = Mapping.substr(EqualsIdx + 1); + + uint64_t Addr; + if (StringRef(AddrStr).getAsInteger(0, Addr)) { + errs() << "Invalid symbol mapping '" << Mapping << "'.\n"; + exit(1); + } + + MemMgr.addDummySymbol(Symbol, Addr); + } } // Load and link the objects specified on the command line, but do not execute @@ -604,8 +649,9 @@ static int linkAndVerify() { } } - // Re-map the section addresses into the phony target address space. - remapSections(TheTriple, MemMgr, Checker); + // Re-map the section addresses into the phony target address space and add + // dummy symbols. + remapSectionsAndSymbols(TheTriple, MemMgr, Checker); // Resolve all the relocations we can. Dyld.resolveRelocations();