[llvm-commits] [PATCH 9/10] Initial support for PowerPC64 MCJIT

Jim Grosbach grosbach at apple.com
Mon Sep 17 14:58:36 PDT 2012


Hello,

First off, this is awesome to see PPC getting MC-ified. Thank you for working on this!

I don't know PPC well enough to comment on the architecture specific aspects of this, but a few general comments inline below:

> From 4ffb3e57d5fd34aec32fec662c9ee3581e186882 Mon Sep 17 00:00:00 2001
> From: Adhemerval Zanella <azanella at linux.vnet.ibm.com>
> Date: Mon, 17 Sep 2012 12:32:35 -0500
> Subject: [PATCH 10/11] Initial support for PowerPC64 MCJIT
> 
> ---
>  lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp    |   18 ++
>  lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp |  279 +++++++++++++++++++-
>  lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h   |   11 +
>  lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h  |    2 +
>  4 files changed, 308 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
> index 880129d..d824845 100644
> --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
> +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
> @@ -362,6 +362,24 @@ uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
>      StubAddr++;
>      *StubAddr = NopInstr;
>      return Addr;
> +  } else if (Arch == Triple::ppc64) {
> +    // PowerPC64 stub: the address points to a function descriptor
> +    // instead of the function itself. Load the function address
> +    // on r11 and sets it to control register. Also loads the function
> +    // TOC in r2 and environment pointer to r11.
> +    uint32_t *StubAddr = (uint32_t*)Addr;
> +    *(StubAddr+0)  = 0x3D800000; // lis   r12, highest(addr)
> +    *(StubAddr+1)  = 0x618C0000; // ori   r12, higher(addr)
> +    *(StubAddr+2)  = 0x798C07C6; // sldi  r12, r12, 32
> +    *(StubAddr+3)  = 0x658C0000; // oris  r12, r12, h(addr)
> +    *(StubAddr+4)  = 0x618C0000; // ori   r12, r12, l(addr)
> +    *(StubAddr+5)  = 0xF8410028; // std   r2,  40(r1)
> +    *(StubAddr+6)  = 0xE96C0000; // ld    r11, 0(r12)
> +    *(StubAddr+7)  = 0xE84C0008; // ld    r2,  0(r12)
> +    *(StubAddr+8)  = 0x7D6903A6; // mtctr r11
> +    *(StubAddr+9)  = 0xE96C0010; // ld    r11, 16(r2)
> +    *(StubAddr+10) = 0x4E800420; // bctr

Is StubAddr guaranteed to be 32-bit aligned? Typically not.

> +    return Addr;
>    }
>    return Addr;
>  }
> diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
> index a1c0e40..ba0dd3c 100644
> --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
> +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
> @@ -27,6 +27,14 @@ using namespace llvm::object;
>  
>  namespace {
>  
> +static inline
> +error_code Check(error_code Err) {
> +  if (Err) {
> +    report_fatal_error(Err.message());
> +  }
> +  return Err;
> +}
> +
>  template<support::endianness target_endianness, bool is64Bits>
>  class DyldELFObject : public ELFObjectFile<target_endianness, is64Bits> {
>    LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits)
> @@ -343,6 +351,183 @@ void RuntimeDyldELF::resolveMIPSRelocation(uint8_t *LocalAddress,
>     }
>  }
>  
> +// Return the .TOC. section address to R_PPC64_TOC relocations.
> +uint64_t RuntimeDyldELF::findPPC64TOC() const
> +{
> +  // The TOC consists of sections .got, .toc, .tocbss, .plt in that
> +  // order. The TOC starts where the first of these sections starts.
> +  SectionList::const_iterator it = Sections.begin();
> +  for (; it != Sections.end(); ++it) {
> +    if ((*it).Name == ".got")

LLVM style is to use the "->" operator here. e.g., "it->Name".

> +      break;
> +    if ((*it).Name == ".toc")
> +      break;
> +    if ((*it).Name == ".tocbss")
> +      break;
> +    if ((*it).Name == ".plt")
> +      break;
> +  }
> +  if (it == Sections.end()) {
> +    // This may happen for
> +    // * references to TOC base base (sym at toc, .odp relocation) without
> +    // a .toc directive.
> +    // In this case lets just use the first section (which is usually

Can omit "lets" here. If you prefer w/ it, it's missing an apostrophe (i.e., "let's").

> +    // the .odp) since the code won't reference the .toc base
> +    // directly.
> +    it = Sections.begin();
> +  }
> +  assert (it != Sections.end());
> +  // Per the ppc64-elf-linux ABI, The TOC base if TOC value plus 0x8000
> +  // thus permitting a full 64 Kbytes segment.
> +  return (*it).LoadAddress + 0x8000;
> +}
> +
> +// Returns the sections and offset associated with the ODP entry referenced
> +// by Symbol.
> +void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
> +                                         ObjSectionToIDMap &LocalSections,
> +                                         RelocationValueRef &Rel)
> +{

Open brace goes on the same line as the close paren of the decl.

> +  // Get the ELF symbol value (st_value) to compare with Relocation offset in
> +  // .opd entries
> +
> +  error_code err;
> +  for (section_iterator si = Obj.begin_sections(),
> +     se = Obj.end_sections(); si != se; si.increment(err)) {
> +    StringRef SectionName;
> +    Check(si->getName(SectionName));
> +    if (SectionName != ".opd")
> +      continue;
> +
> +    for (relocation_iterator i = si->begin_relocations(),
> +         e = si->end_relocations(); i != e;) {
> +      Check(err);
> +
> +      // The R_PPC64_ADDR64 relocation indicates the first field
> +      // of a .opd entry
> +      uint64_t TypeFunc;
> +      Check(i->getType(TypeFunc));
> +      if (TypeFunc != ELF::R_PPC64_ADDR64) {
> +        i.increment(err);
> +        continue;
> +      }
> +
> +      SymbolRef TargetSymbol;
> +      Check(i->getSymbol(TargetSymbol));
> +      uint64_t TargetSymbolOffset;
> +      Check(i->getOffset(TargetSymbolOffset));
> +      int64_t TargetAdditionalInfo;
> +      Check(i->getAdditionalInfo(TargetAdditionalInfo));
> +
> +      i = i.increment(err);
> +      if (i == e)
> +        break;
> +      Check(err);
> +
> +      // Just check if following relocation is a R_PPC64_TOC
> +      uint64_t TypeTOC;
> +      Check(i->getType(TypeTOC));
> +      if (TypeTOC != ELF::R_PPC64_TOC)
> +        continue;
> +
> +      // Finally compares the Symbol value and the target symbol offset
> +      // to check if this .opd entry refers to the symbol the relocation
> +      // points to.
> +      if (Rel.Addend != (intptr_t)TargetSymbolOffset)
> +        continue;
> +
> +      section_iterator tsi(Obj.end_sections());
> +      Check(TargetSymbol.getSection(tsi));
> +      Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
> +      Rel.Addend = (intptr_t)TargetAdditionalInfo;
> +      return;
> +    }
> +  }
> +  llvm_unreachable("Attempting to get address of ODP entry!");
> +}
> +
> +static inline
> +uint16_t ppc_lo (uint64_t value)
> +{
> +  return value & 0xffff;
> +}
> +
> +static inline
> +uint16_t ppc_hi (uint64_t value)
> +{
> +  return (value >> 16) & 0xffff;
> +}
> +
> +static inline
> +uint16_t ppc_higher (uint64_t value)
> +{
> +  return (value >> 32) & 0xffff;
> +}
> +
> +static inline
> +uint16_t ppc_highest (uint64_t value)
> +{
> +  return (value >> 48) & 0xffff;
> +}

The names for these functions are a) ambiguous and b) not following LLVM's naming guidelines. Please review: http://llvm.org/docs/CodingStandards.html#coding-standards

> +
> +void RuntimeDyldELF::resolvePPC64Relocation(uint8_t *LocalAddress,
> +					    uint64_t FinalAddress,
> +					    uint64_t Value,
> +					    uint32_t Type,
> +					    int64_t Addend) {
> +  uint64_t* RelocAddr = (uint64_t*)LocalAddress;
> +  switch (Type) {
> +  default:
> +    llvm_unreachable("Relocation type not implemented yet!");
> +  break;
> +  case ELF::R_PPC64_ADDR16_LO :
> +    *((uint16_t*)RelocAddr+1) = ppc_lo (Value + Addend);

LocalAddress is not guaranteed to be 16-bit aligned. Ditto on below references.

> +    break;
> +  case ELF::R_PPC64_ADDR16_HI :
> +    *((uint16_t*)RelocAddr+1) = ppc_hi (Value + Addend);
> +    break;
> +  case ELF::R_PPC64_ADDR16_HIGHER :
> +    *((uint16_t*)RelocAddr+1) = ppc_higher (Value + Addend);
> +    break;
> +  case ELF::R_PPC64_ADDR16_HIGHEST :
> +    *((uint16_t*)RelocAddr+1) = ppc_highest (Value + Addend);
> +    break;
> +  case ELF::R_PPC64_ADDR14 :
> +    {
> +      assert(((Value + Addend) & 3) == 0);
> +      uint16_t *insn = ((uint16_t*)RelocAddr+1);
> +      *insn = (*insn & 3) | ((Value + Addend) & 0xfffc);
> +    } break;
> +  case ELF::R_PPC64_REL24 :
> +    {
> +      int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
> +      if (SignExtend32<24>(delta) != delta)
> +        llvm_unreachable("Relocation R_PPC64_REL24 overflow");
> +      // Generates a 'bl <address>' instruction
> +      *(uint32_t*)(RelocAddr) = 0x48000001 | (delta & 0x03FFFFFC);
> +    } break;
> +  case ELF::R_PPC64_ADDR64 :
> +    *RelocAddr = Value + Addend;
> +    break;
> +  case ELF::R_PPC64_TOC :
> +    *RelocAddr = findPPC64TOC();
> +    break;
> +  case ELF::R_PPC64_TOC16 :
> +    {
> +      uint64_t TOCStart = findPPC64TOC();
> +      Value = ppc_lo((Value + Addend) - TOCStart);
> +      *((uint16_t*)RelocAddr) = ppc_lo (Value);
> +    } break;
> +  case ELF::R_PPC64_TOC16_DS :
> +    {
> +      uint64_t TOCStart = findPPC64TOC();
> +      Value = ((Value + Addend) - TOCStart);
> +      *((uint16_t*)RelocAddr) = ppc_lo (Value);
> +    } break;
> +  }
> +}
> +
> +
>  void RuntimeDyldELF::resolveRelocation(uint8_t *LocalAddress,
>                                         uint64_t FinalAddress,
>                                         uint64_t Value,
> @@ -369,6 +554,9 @@ void RuntimeDyldELF::resolveRelocation(uint8_t *LocalAddress,
>                            (uint32_t)(Value & 0xffffffffL), Type,
>                            (uint32_t)(Addend & 0xffffffffL));
>      break;
> +  case Triple::ppc64:
> +    resolvePPC64Relocation(LocalAddress, FinalAddress, Value, Type, Addend);
> +    break;
>    default: llvm_unreachable("Unsupported CPU type!");
>    }
>  }
> @@ -393,6 +581,8 @@ void RuntimeDyldELF::processRelocationRef(const ObjRelocationInfo &Rel,
>    RelocationValueRef Value;
>    // First search for the symbol in the local symbol table
>    SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
> +  SymbolRef::Type SymType;
> +  Symbol.getType(SymType);
>    if (lsi != Symbols.end()) {
>      Value.SectionID = lsi->second.first;
>      Value.Addend = lsi->second.second;
> @@ -404,8 +594,6 @@ void RuntimeDyldELF::processRelocationRef(const ObjRelocationInfo &Rel,
>        Value.SectionID = gsi->second.first;
>        Value.Addend = gsi->second.second;
>      } else {
> -      SymbolRef::Type SymType;
> -      Symbol.getType(SymType);
>        switch (SymType) {
>          case SymbolRef::ST_Debug: {
>            // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
> @@ -513,6 +701,93 @@ void RuntimeDyldELF::processRelocationRef(const ObjRelocationInfo &Rel,
>                          Section.StubOffset, RelType, 0);
>        Section.StubOffset += getMaxStubSize();
>      }
> +  } else if (Arch == Triple::ppc64) {
> +    if (RelType == ELF::R_PPC64_REL24) {
> +      // A PPC branch relocation will need a stub function if the target is
> +      // an external symbol (Symbol::ST_Unknown) or if the target address
> +      // is not within the signed 24-bits branch address.
> +      SectionEntry &Section = Sections[Rel.SectionID];
> +      uint8_t *Target = Section.Address + Rel.Offset;
> +      bool RangeOverflow = false;
> +      if (SymType != SymbolRef::ST_Unknown) {
> +        // A function call may points to the .opd entry, so the final symbol value
> +        // in calculated based in the relocation values in .opd section.
> +        findOPDEntrySection(Obj, ObjSectionToID, Value);
> +        uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
> +        int32_t delta = static_cast<int32_t>(Target - RelocTarget);
> +        // If it is within 24-bits branch range, just set the branch target
> +        if (SignExtend32<24>(delta) == delta) {
> +          RelocationEntry RE(Rel.SectionID, Rel.Offset, RelType, Value.Addend);
> +          if (Value.SymbolName)
> +            addRelocationForSymbol(RE, Value.SymbolName);
> +          else
> +            addRelocationForSection(RE, Value.SectionID);
> +        } else {
> +          RangeOverflow = true;
> +        }
> +      }
> +      if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
> +        // It is an external symbol (SymbolRef::ST_Unknown) or within a range
> +        // larger than 24-bits.
> +        StubMap::const_iterator i = Stubs.find(Value);
> +        if (i != Stubs.end()) {
> +          // Symbol function stub already created, just relocate to it
> +          resolveRelocation(Target, (uint64_t)Target, (uint64_t)Section.Address
> +                            + i->second, RelType, 0);
> +          DEBUG(dbgs() << " Stub function found\n");
> +        } else {
> +          // Create a new stub function.
> +          DEBUG(dbgs() << " Create a new stub function\n");
> +          Stubs[Value] = Section.StubOffset;
> +          uint8_t *StubTargetAddr = createStubFunction(Section.Address +
> +                                                       Section.StubOffset);
> +          RelocationEntry RE(Rel.SectionID, StubTargetAddr - Section.Address,
> +                             ELF::R_PPC64_ADDR64, Value.Addend);
> +
> +          // Generates the 64-bits address loads as exemplified in section
> +          // 4.5.1 in PPC64 ELF ABI.
> +          RelocationEntry REhst(Rel.SectionID,
> +                                StubTargetAddr - Section.Address,
> +                                ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
> +          RelocationEntry REhr(Rel.SectionID,
> +                               StubTargetAddr - Section.Address + 4,
> +                               ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
> +          RelocationEntry REh(Rel.SectionID,
> +                              StubTargetAddr - Section.Address + 12,
> +                              ELF::R_PPC64_ADDR16_HI, Value.Addend);
> +          RelocationEntry REl(Rel.SectionID,
> +                              StubTargetAddr - Section.Address + 16,
> +                              ELF::R_PPC64_ADDR16_LO, Value.Addend);
> +
> +          if (Value.SymbolName) {
> +            addRelocationForSymbol(REhst, Value.SymbolName);
> +            addRelocationForSymbol(REhr,  Value.SymbolName);
> +            addRelocationForSymbol(REh,   Value.SymbolName);
> +            addRelocationForSymbol(REl,   Value.SymbolName);
> +          } else {
> +            addRelocationForSection(REhst, Value.SectionID);
> +            addRelocationForSection(REhr,  Value.SectionID);
> +            addRelocationForSection(REh,   Value.SectionID);
> +            addRelocationForSection(REl,   Value.SectionID);
> +          }
> +
> +          resolveRelocation(Target, (uint64_t)Target, (uint64_t)Section.Address
> +                            + Section.StubOffset, RelType, 0);
> +          if (SymType == SymbolRef::ST_Unknown)
> +            // Restore the TOC for external calls
> +            *((uint32_t*)Target+1) = 0xE8410028;  // ld r2,40(r1)
> +          Section.StubOffset += getMaxStubSize();
> +        }
> +      }
> +    } else {
> +      RelocationEntry RE(Rel.SectionID, Rel.Offset, RelType, Value.Addend);
> +      // Extra check to avoid relocation againt empty symbols (usually
> +      // the R_PPC64_TOC).
> +      if (Value.SymbolName && !TargetName.empty())
> +        addRelocationForSymbol(RE, Value.SymbolName);
> +      else
> +        addRelocationForSection(RE, Value.SectionID);
> +    }
>    } else {
>      RelocationEntry RE(Rel.SectionID, Rel.Offset, RelType, Value.Addend);
>      if (Value.SymbolName)
> diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
> index eade49e..997351b 100644
> --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
> +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
> @@ -48,6 +48,12 @@ protected:
>                               uint32_t Type,
>                               int32_t Addend);
>  
> +  void resolvePPC64Relocation(uint8_t *LocalAddress,
> +                              uint64_t FinalAddress,
> +                              uint64_t Value,
> +                              uint32_t Type,
> +                              int64_t Addend);
> +
>    virtual void resolveRelocation(uint8_t *LocalAddress,
>                                   uint64_t FinalAddress,
>                                   uint64_t Value,
> @@ -63,6 +69,11 @@ protected:
>    virtual ObjectImage *createObjectImage(const MemoryBuffer *InputBuffer);
>    virtual void handleObjectLoaded(ObjectImage *Obj);
>  
> +  uint64_t findPPC64TOC() const;
> +  void findOPDEntrySection(ObjectImage &Obj,
> +                           ObjSectionToIDMap &LocalSections,
> +                           RelocationValueRef &Rel);
> +
>  public:
>    RuntimeDyldELF(RTDyldMemoryManager *mm)
>        : RuntimeDyldImpl(mm), LoadedObject(0) {}
> diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
> index b29ff40..47807eb 100644
> --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
> +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
> @@ -166,6 +166,8 @@ protected:
>        return 8; // 32-bit instruction and 32-bit address
>      else if (Arch == Triple::mipsel)
>        return 16;
> +    else if (Arch == Triple::ppc64)
> +      return 44;
>      else
>        return 0;
>    }
> -- 
> 1.7.1
> 
On Sep 17, 2012, at 1:21 PM, Adhemerval Zanella <azanella at linux.vnet.ibm.com> wrote:

> This is the initial support of MCJIT for PPC64-elf-abi. I didn't add any testcase
> because I focused on existing ones. It correctly runs the following ones:
> 
> ExecutionEngine/2003-01-04-ArgumentBug.ll
> ExecutionEngine/2003-01-04-LoopTest.ll
> ExecutionEngine/2003-01-04-PhiTest.ll
> ExecutionEngine/2003-01-09-SARTest.ll
> ExecutionEngine/2003-01-10-FUCOM.ll
> ExecutionEngine/2003-01-15-AlignmentTest.ll
> ExecutionEngine/2003-05-11-PHIRegAllocBug.ll
> ExecutionEngine/2003-06-04-bzip2-bug.ll
> ExecutionEngine/2003-06-05-PHIBug.ll
> ExecutionEngine/2003-08-15-AllocaAssertion.ll
> ExecutionEngine/2003-08-21-EnvironmentTest.ll
> ExecutionEngine/2003-08-23-RegisterAllocatePhysReg.ll
> ExecutionEngine/2003-10-18-PHINode-ConstantExpr-CondCode-Failure.ll
> ExecutionEngine/simplesttest.ll
> ExecutionEngine/simpletest.ll
> ExecutionEngine/stubs.ll
> ExecutionEngine/test-arith.ll
> ExecutionEngine/test-branch.ll
> ExecutionEngine/test-call-no-external-funcs.ll
> ExecutionEngine/test-cast.ll
> ExecutionEngine/test-common-symbols.ll
> ExecutionEngine/test-constantexpr.ll
> ExecutionEngine/test-fp-no-external-funcs.ll
> ExecutionEngine/test-fp.ll
> ExecutionEngine/test-global-init-nonzero.ll
> ExecutionEngine/test-global.ll
> ExecutionEngine/test-loadstore.ll
> ExecutionEngine/test-local.ll
> ExecutionEngine/test-logical.ll
> ExecutionEngine/test-loop.ll
> ExecutionEngine/test-phi.ll
> ExecutionEngine/test-ret.ll
> ExecutionEngine/test-return.ll
> ExecutionEngine/test-setcond-fp.ll
> ExecutionEngine/test-setcond-int.ll
> ExecutionEngine/test-shift.ll      
> 
> -- 
> Adhemerval Zanella Netto
>  Software Engineer
>  Linux Technology Center Brazil
>  Toolchain / GLIBC on Power Architecture
>  azanella at linux.vnet.ibm.com / azanella at br.ibm.com
>  +55 61 8642-9890
> 
> <0010-Initial-support-for-PowerPC64-MCJIT.patch>_______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

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