lib/ExecutionEngine/Orc/OrcTargetSupport.cpp

   1 //===------- OrcTargetSupport.cpp - Target support utilities for Orc ------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/ADT/Triple.h"
  11 #include "llvm/ExecutionEngine/Orc/OrcTargetSupport.h"
  12 #include "llvm/Support/Process.h"
  13 #include <array>
  14
  15 using namespace llvm::orc;
  16
  17 namespace {
  18
  19 uint64_t executeCompileCallback(JITCompileCallbackManagerBase *JCBM,
  20                                 TargetAddress CallbackID) {
  21   return JCBM->executeCompileCallback(CallbackID);
  22 }
  23
  24 }
  25
  26 namespace llvm {
  27 namespace orc {
  28
  29 const char* OrcX86_64::ResolverBlockName = "orc_resolver_block";
  30
  31 void OrcX86_64::insertResolverBlock(
  32     Module &M, JITCompileCallbackManagerBase &JCBM) {
  33
  34   // Trampoline code-sequence length, used to get trampoline address from return
  35   // address.
  36   const unsigned X86_64_TrampolineLength = 6;
  37
  38   // List of x86-64 GPRs to save. Note - RBP saved separately below.
  39   std::array<const char *, 14> GPRs = {{
  40       "rax", "rbx", "rcx", "rdx",
  41       "rsi", "rdi", "r8", "r9",
  42       "r10", "r11", "r12", "r13",
  43       "r14", "r15"
  44     }};
  45
  46   // Address of the executeCompileCallback function.
  47   uint64_t CallbackAddr =
  48       static_cast<uint64_t>(
  49         reinterpret_cast<uintptr_t>(executeCompileCallback));
  50
  51   std::ostringstream AsmStream;
  52   Triple TT(M.getTargetTriple());
  53
  54   // Switch to text section.
  55   if (TT.getOS() == Triple::Darwin)
  56     AsmStream << ".section __TEXT,__text,regular,pure_instructions\n"
  57               << ".align 4, 0x90\n";
  58   else
  59     AsmStream << ".text\n"
  60               << ".align 16, 0x90\n";
  61
  62   // Bake in a pointer to the callback manager immediately before the
  63   // start of the resolver function.
  64   AsmStream << "jit_callback_manager_addr:\n"
  65             << "  .quad " << &JCBM << "\n";
  66
  67   // Start the resolver function.
  68   AsmStream << ResolverBlockName << ":\n"
  69             << "  pushq     %rbp\n"
  70             << "  movq      %rsp, %rbp\n";
  71
  72   // Store the GPRs.
  73   for (const auto &GPR : GPRs)
  74     AsmStream << "  pushq     %" << GPR << "\n";
  75
  76   // Store floating-point state with FXSAVE.
  77   // Note: We need to keep the stack 16-byte aligned, so if we've emitted an odd
  78   //       number of 64-bit pushes so far (GPRs.size() plus 1 for RBP) then add
  79   //       an extra 64 bits of padding to the FXSave area.
  80   unsigned Padding = (GPRs.size() + 1) % 2 ? 8 : 0;
  81   unsigned FXSaveSize = 512 + Padding;
  82   AsmStream << "  subq      $" << FXSaveSize << ", %rsp\n"
  83             << "  fxsave64  (%rsp)\n"
  84
  85   // Load callback manager address, compute trampoline address, call JIT.
  86             << "  lea       jit_callback_manager_addr(%rip), %rdi\n"
  87             << "  movq      (%rdi), %rdi\n"
  88             << "  movq      0x8(%rbp), %rsi\n"
  89             << "  subq      $" << X86_64_TrampolineLength << ", %rsi\n"
  90             << "  movabsq   $" << CallbackAddr << ", %rax\n"
  91             << "  callq     *%rax\n"
  92
  93   // Replace the return to the trampoline with the return address of the
  94   // compiled function body.
  95             << "  movq      %rax, 0x8(%rbp)\n"
  96
  97   // Restore the floating point state.
  98             << "  fxrstor64 (%rsp)\n"
  99             << "  addq      $" << FXSaveSize << ", %rsp\n";
 100
 101   for (const auto &GPR : make_range(GPRs.rbegin(), GPRs.rend()))
 102     AsmStream << "  popq      %" << GPR << "\n";
 103
 104   // Restore original RBP and return to compiled function body.
 105   AsmStream << "  popq      %rbp\n"
 106             << "  retq\n";
 107
 108   M.appendModuleInlineAsm(AsmStream.str());
 109 }
 110
 111 OrcX86_64::LabelNameFtor
 112 OrcX86_64::insertCompileCallbackTrampolines(Module &M,
 113                                             TargetAddress ResolverBlockAddr,
 114                                             unsigned NumCalls,
 115                                             unsigned StartIndex) {
 116   const char *ResolverBlockPtrName = "Lorc_resolve_block_addr";
 117
 118   std::ostringstream AsmStream;
 119   Triple TT(M.getTargetTriple());
 120
 121   if (TT.getOS() == Triple::Darwin)
 122     AsmStream << ".section __TEXT,__text,regular,pure_instructions\n"
 123               << ".align 4, 0x90\n";
 124   else
 125     AsmStream << ".text\n"
 126               << ".align 16, 0x90\n";
 127
 128   AsmStream << ResolverBlockPtrName << ":\n"
 129             << "  .quad " << ResolverBlockAddr << "\n";
 130
 131   auto GetLabelName =
 132     [=](unsigned I) {
 133       std::ostringstream LabelStream;
 134       LabelStream << "orc_jcc_" << (StartIndex + I);
 135       return LabelStream.str();
 136   };
 137
 138   for (unsigned I = 0; I < NumCalls; ++I)
 139     AsmStream << GetLabelName(I) << ":\n"
 140               << "  callq *" << ResolverBlockPtrName << "(%rip)\n";
 141
 142   M.appendModuleInlineAsm(AsmStream.str());
 143
 144   return GetLabelName;
 145 }
 146
 147 OrcX86_64::IndirectStubsInfo::~IndirectStubsInfo() {
 148   sys::Memory::releaseMappedMemory(StubsBlock);
 149   sys::Memory::releaseMappedMemory(PtrsBlock);
 150 }
 151
 152 std::error_code OrcX86_64::emitIndirectStubsBlock(IndirectStubsInfo &StubsInfo,
 153                                                   unsigned MinStubs,
 154                                                   void *InitialPtrVal) {
 155   // Stub format is:
 156   //
 157   // .section __orc_stubs
 158   // stub1:
 159   //                 jmpq    *ptr1(%rip)
 160   //                 .byte   0xC4         ; <- Invalid opcode padding.
 161   //                 .byte   0xF1
 162   // stub2:
 163   //                 jmpq    *ptr2(%rip)
 164   //
 165   // ...
 166   //
 167   // .section __orc_ptrs
 168   // ptr1:
 169   //                 .quad 0x0
 170   // ptr2:
 171   //                 .quad 0x0
 172   //
 173   // ...
 174
 175   const unsigned StubSize = IndirectStubsInfo::StubSize;
 176
 177   // Emit at least MinStubs, rounded up to fill the pages allocated.
 178   unsigned PageSize = sys::Process::getPageSize();
 179   unsigned NumPages = ((MinStubs * StubSize) + (PageSize - 1)) / PageSize;
 180   unsigned NumStubs = (NumPages * PageSize) / StubSize;
 181
 182   // Allocate memory for stubs and pointers in one call.
 183   std::error_code EC;
 184   auto InitialBlock = sys::Memory::allocateMappedMemory(2 * NumPages * PageSize,
 185                                                         nullptr,
 186                                                         sys::Memory::MF_READ |
 187                                                         sys::Memory::MF_WRITE,
 188                                                         EC);
 189
 190   if (EC)
 191     return EC;
 192
 193   // Create separate MemoryBlocks representing the stubs and pointers.
 194   sys::MemoryBlock StubsBlock(InitialBlock.base(), NumPages * PageSize);
 195   sys::MemoryBlock PtrsBlock(static_cast<char*>(InitialBlock.base()) +
 196                              NumPages * PageSize,
 197                              NumPages * PageSize);
 198
 199   // Populate the stubs page stubs and mark it executable.
 200   uint64_t *Stub = reinterpret_cast<uint64_t*>(StubsBlock.base());
 201   uint64_t PtrOffsetField =
 202     static_cast<uint64_t>(NumPages * PageSize - 6) << 16;
 203   for (unsigned I = 0; I < NumStubs; ++I)
 204     Stub[I] = 0xF1C40000000025ff | PtrOffsetField;
 205
 206   if (auto EC = sys::Memory::protectMappedMemory(StubsBlock,
 207                                                  sys::Memory::MF_READ |
 208                                                  sys::Memory::MF_EXEC))
 209     return EC;
 210
 211   // Initialize all pointers to point at FailureAddress.
 212   void **Ptr = reinterpret_cast<void**>(PtrsBlock.base());
 213   for (unsigned I = 0; I < NumStubs; ++I)
 214     Ptr[I] = InitialPtrVal;
 215
 216   StubsInfo.NumStubs = NumStubs;
 217   StubsInfo.StubsBlock = std::move(StubsBlock);
 218   StubsInfo.PtrsBlock = std::move(PtrsBlock);
 219
 220   return std::error_code();
 221 }
 222
 223 } // End namespace orc.
 224 } // End namespace llvm.