1//===-- X86JITInfo.cpp - Implement the JIT interfaces for the X86 target --===//
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// This file implements the JIT interfaces for the X86 target.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "jit"
15#include "X86JITInfo.h"
16#include "X86Relocations.h"
17#include "X86Subtarget.h"
18#include "X86TargetMachine.h"
19#include "llvm/Function.h"
20#include "llvm/Support/Compiler.h"
21#include "llvm/Support/ErrorHandling.h"
22#include "llvm/Support/Valgrind.h"
23#include <cstdlib>
24#include <cstring>
25using namespace llvm;
26
27// Determine the platform we're running on
28#if defined (__x86_64__) || defined (_M_AMD64) || defined (_M_X64)
29# define X86_64_JIT
30#elif defined(__i386__) || defined(i386) || defined(_M_IX86)
31# define X86_32_JIT
32#endif
33
34void X86JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
35  unsigned char *OldByte = (unsigned char *)Old;
36  *OldByte++ = 0xE9;                // Emit JMP opcode.
37  unsigned *OldWord = (unsigned *)OldByte;
38  unsigned NewAddr = (intptr_t)New;
39  unsigned OldAddr = (intptr_t)OldWord;
40  *OldWord = NewAddr - OldAddr - 4; // Emit PC-relative addr of New code.
41
42  // X86 doesn't need to invalidate the processor cache, so just invalidate
43  // Valgrind's cache directly.
44  sys::ValgrindDiscardTranslations(Old, 5);
45}
46
47
48/// JITCompilerFunction - This contains the address of the JIT function used to
49/// compile a function lazily.
50static TargetJITInfo::JITCompilerFn JITCompilerFunction;
51
52// Get the ASMPREFIX for the current host.  This is often '_'.
53#ifndef __USER_LABEL_PREFIX__
54#define __USER_LABEL_PREFIX__
55#endif
56#define GETASMPREFIX2(X) #X
57#define GETASMPREFIX(X) GETASMPREFIX2(X)
58#define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
59
60// For ELF targets, use a .size and .type directive, to let tools
61// know the extent of functions defined in assembler.
62#if defined(__ELF__)
63# define SIZE(sym) ".size " #sym ", . - " #sym "\n"
64# define TYPE_FUNCTION(sym) ".type " #sym ", @function\n"
65#else
66# define SIZE(sym)
67# define TYPE_FUNCTION(sym)
68#endif
69
70// Provide a convenient way for disabling usage of CFI directives.
71// This is needed for old/broken assemblers (for example, gas on
72// Darwin is pretty old and doesn't support these directives)
73#if defined(__APPLE__)
74# define CFI(x)
75#else
76// FIXME: Disable this until we really want to use it. Also, we will
77//        need to add some workarounds for compilers, which support
78//        only subset of these directives.
79# define CFI(x)
80#endif
81
82// Provide a wrapper for X86CompilationCallback2 that saves non-traditional
83// callee saved registers, for the fastcc calling convention.
84extern "C" {
85#if defined(X86_64_JIT)
86# ifndef _MSC_VER
87  // No need to save EAX/EDX for X86-64.
88  void X86CompilationCallback(void);
89  asm(
90    ".text\n"
91    ".align 8\n"
92    ".globl " ASMPREFIX "X86CompilationCallback\n"
93    TYPE_FUNCTION(X86CompilationCallback)
94  ASMPREFIX "X86CompilationCallback:\n"
95    CFI(".cfi_startproc\n")
96    // Save RBP
97    "pushq   %rbp\n"
98    CFI(".cfi_def_cfa_offset 16\n")
99    CFI(".cfi_offset %rbp, -16\n")
100    // Save RSP
101    "movq    %rsp, %rbp\n"
102    CFI(".cfi_def_cfa_register %rbp\n")
103    // Save all int arg registers
104    "pushq   %rdi\n"
105    CFI(".cfi_rel_offset %rdi, 0\n")
106    "pushq   %rsi\n"
107    CFI(".cfi_rel_offset %rsi, 8\n")
108    "pushq   %rdx\n"
109    CFI(".cfi_rel_offset %rdx, 16\n")
110    "pushq   %rcx\n"
111    CFI(".cfi_rel_offset %rcx, 24\n")
112    "pushq   %r8\n"
113    CFI(".cfi_rel_offset %r8, 32\n")
114    "pushq   %r9\n"
115    CFI(".cfi_rel_offset %r9, 40\n")
116    // Align stack on 16-byte boundary. ESP might not be properly aligned
117    // (8 byte) if this is called from an indirect stub.
118    "andq    $-16, %rsp\n"
119    // Save all XMM arg registers
120    "subq    $128, %rsp\n"
121    "movaps  %xmm0, (%rsp)\n"
122    "movaps  %xmm1, 16(%rsp)\n"
123    "movaps  %xmm2, 32(%rsp)\n"
124    "movaps  %xmm3, 48(%rsp)\n"
125    "movaps  %xmm4, 64(%rsp)\n"
126    "movaps  %xmm5, 80(%rsp)\n"
127    "movaps  %xmm6, 96(%rsp)\n"
128    "movaps  %xmm7, 112(%rsp)\n"
129    // JIT callee
130#ifdef _WIN64
131    "subq    $32, %rsp\n"
132    "movq    %rbp, %rcx\n"    // Pass prev frame and return address
133    "movq    8(%rbp), %rdx\n"
134    "call    " ASMPREFIX "X86CompilationCallback2\n"
135    "addq    $32, %rsp\n"
136#else
137    "movq    %rbp, %rdi\n"    // Pass prev frame and return address
138    "movq    8(%rbp), %rsi\n"
139    "call    " ASMPREFIX "X86CompilationCallback2\n"
140#endif
141    // Restore all XMM arg registers
142    "movaps  112(%rsp), %xmm7\n"
143    "movaps  96(%rsp), %xmm6\n"
144    "movaps  80(%rsp), %xmm5\n"
145    "movaps  64(%rsp), %xmm4\n"
146    "movaps  48(%rsp), %xmm3\n"
147    "movaps  32(%rsp), %xmm2\n"
148    "movaps  16(%rsp), %xmm1\n"
149    "movaps  (%rsp), %xmm0\n"
150    // Restore RSP
151    "movq    %rbp, %rsp\n"
152    CFI(".cfi_def_cfa_register %rsp\n")
153    // Restore all int arg registers
154    "subq    $48, %rsp\n"
155    CFI(".cfi_adjust_cfa_offset 48\n")
156    "popq    %r9\n"
157    CFI(".cfi_adjust_cfa_offset -8\n")
158    CFI(".cfi_restore %r9\n")
159    "popq    %r8\n"
160    CFI(".cfi_adjust_cfa_offset -8\n")
161    CFI(".cfi_restore %r8\n")
162    "popq    %rcx\n"
163    CFI(".cfi_adjust_cfa_offset -8\n")
164    CFI(".cfi_restore %rcx\n")
165    "popq    %rdx\n"
166    CFI(".cfi_adjust_cfa_offset -8\n")
167    CFI(".cfi_restore %rdx\n")
168    "popq    %rsi\n"
169    CFI(".cfi_adjust_cfa_offset -8\n")
170    CFI(".cfi_restore %rsi\n")
171    "popq    %rdi\n"
172    CFI(".cfi_adjust_cfa_offset -8\n")
173    CFI(".cfi_restore %rdi\n")
174    // Restore RBP
175    "popq    %rbp\n"
176    CFI(".cfi_adjust_cfa_offset -8\n")
177    CFI(".cfi_restore %rbp\n")
178    "ret\n"
179    CFI(".cfi_endproc\n")
180    SIZE(X86CompilationCallback)
181  );
182# else
183  // No inline assembler support on this platform. The routine is in external
184  // file.
185  void X86CompilationCallback();
186
187# endif
188#elif defined (X86_32_JIT)
189# ifndef _MSC_VER
190  void X86CompilationCallback(void);
191  asm(
192    ".text\n"
193    ".align 8\n"
194    ".globl " ASMPREFIX "X86CompilationCallback\n"
195    TYPE_FUNCTION(X86CompilationCallback)
196  ASMPREFIX "X86CompilationCallback:\n"
197    CFI(".cfi_startproc\n")
198    "pushl   %ebp\n"
199    CFI(".cfi_def_cfa_offset 8\n")
200    CFI(".cfi_offset %ebp, -8\n")
201    "movl    %esp, %ebp\n"    // Standard prologue
202    CFI(".cfi_def_cfa_register %ebp\n")
203    "pushl   %eax\n"
204    CFI(".cfi_rel_offset %eax, 0\n")
205    "pushl   %edx\n"          // Save EAX/EDX/ECX
206    CFI(".cfi_rel_offset %edx, 4\n")
207    "pushl   %ecx\n"
208    CFI(".cfi_rel_offset %ecx, 8\n")
209#  if defined(__APPLE__)
210    "andl    $-16, %esp\n"    // Align ESP on 16-byte boundary
211#  endif
212    "subl    $16, %esp\n"
213    "movl    4(%ebp), %eax\n" // Pass prev frame and return address
214    "movl    %eax, 4(%esp)\n"
215    "movl    %ebp, (%esp)\n"
216    "call    " ASMPREFIX "X86CompilationCallback2\n"
217    "movl    %ebp, %esp\n"    // Restore ESP
218    CFI(".cfi_def_cfa_register %esp\n")
219    "subl    $12, %esp\n"
220    CFI(".cfi_adjust_cfa_offset 12\n")
221    "popl    %ecx\n"
222    CFI(".cfi_adjust_cfa_offset -4\n")
223    CFI(".cfi_restore %ecx\n")
224    "popl    %edx\n"
225    CFI(".cfi_adjust_cfa_offset -4\n")
226    CFI(".cfi_restore %edx\n")
227    "popl    %eax\n"
228    CFI(".cfi_adjust_cfa_offset -4\n")
229    CFI(".cfi_restore %eax\n")
230    "popl    %ebp\n"
231    CFI(".cfi_adjust_cfa_offset -4\n")
232    CFI(".cfi_restore %ebp\n")
233    "ret\n"
234    CFI(".cfi_endproc\n")
235    SIZE(X86CompilationCallback)
236  );
237
238  // Same as X86CompilationCallback but also saves XMM argument registers.
239  void X86CompilationCallback_SSE(void);
240  asm(
241    ".text\n"
242    ".align 8\n"
243    ".globl " ASMPREFIX "X86CompilationCallback_SSE\n"
244    TYPE_FUNCTION(X86CompilationCallback_SSE)
245  ASMPREFIX "X86CompilationCallback_SSE:\n"
246    CFI(".cfi_startproc\n")
247    "pushl   %ebp\n"
248    CFI(".cfi_def_cfa_offset 8\n")
249    CFI(".cfi_offset %ebp, -8\n")
250    "movl    %esp, %ebp\n"    // Standard prologue
251    CFI(".cfi_def_cfa_register %ebp\n")
252    "pushl   %eax\n"
253    CFI(".cfi_rel_offset %eax, 0\n")
254    "pushl   %edx\n"          // Save EAX/EDX/ECX
255    CFI(".cfi_rel_offset %edx, 4\n")
256    "pushl   %ecx\n"
257    CFI(".cfi_rel_offset %ecx, 8\n")
258    "andl    $-16, %esp\n"    // Align ESP on 16-byte boundary
259    // Save all XMM arg registers
260    "subl    $64, %esp\n"
261    // FIXME: provide frame move information for xmm registers.
262    // This can be tricky, because CFA register is ebp (unaligned)
263    // and we need to produce offsets relative to it.
264    "movaps  %xmm0, (%esp)\n"
265    "movaps  %xmm1, 16(%esp)\n"
266    "movaps  %xmm2, 32(%esp)\n"
267    "movaps  %xmm3, 48(%esp)\n"
268    "subl    $16, %esp\n"
269    "movl    4(%ebp), %eax\n" // Pass prev frame and return address
270    "movl    %eax, 4(%esp)\n"
271    "movl    %ebp, (%esp)\n"
272    "call    " ASMPREFIX "X86CompilationCallback2\n"
273    "addl    $16, %esp\n"
274    "movaps  48(%esp), %xmm3\n"
275    CFI(".cfi_restore %xmm3\n")
276    "movaps  32(%esp), %xmm2\n"
277    CFI(".cfi_restore %xmm2\n")
278    "movaps  16(%esp), %xmm1\n"
279    CFI(".cfi_restore %xmm1\n")
280    "movaps  (%esp), %xmm0\n"
281    CFI(".cfi_restore %xmm0\n")
282    "movl    %ebp, %esp\n"    // Restore ESP
283    CFI(".cfi_def_cfa_register esp\n")
284    "subl    $12, %esp\n"
285    CFI(".cfi_adjust_cfa_offset 12\n")
286    "popl    %ecx\n"
287    CFI(".cfi_adjust_cfa_offset -4\n")
288    CFI(".cfi_restore %ecx\n")
289    "popl    %edx\n"
290    CFI(".cfi_adjust_cfa_offset -4\n")
291    CFI(".cfi_restore %edx\n")
292    "popl    %eax\n"
293    CFI(".cfi_adjust_cfa_offset -4\n")
294    CFI(".cfi_restore %eax\n")
295    "popl    %ebp\n"
296    CFI(".cfi_adjust_cfa_offset -4\n")
297    CFI(".cfi_restore %ebp\n")
298    "ret\n"
299    CFI(".cfi_endproc\n")
300    SIZE(X86CompilationCallback_SSE)
301  );
302# else
303  // the following function is called only from this translation unit,
304  // unless we are under 64bit Windows with MSC, where there is
305  // no support for inline assembly
306  static void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr);
307
308  _declspec(naked) void X86CompilationCallback(void) {
309    __asm {
310      push  ebp
311      mov   ebp, esp
312      push  eax
313      push  edx
314      push  ecx
315      and   esp, -16
316      sub   esp, 16
317      mov   eax, dword ptr [ebp+4]
318      mov   dword ptr [esp+4], eax
319      mov   dword ptr [esp], ebp
320      call  X86CompilationCallback2
321      mov   esp, ebp
322      sub   esp, 12
323      pop   ecx
324      pop   edx
325      pop   eax
326      pop   ebp
327      ret
328    }
329  }
330
331# endif // _MSC_VER
332
333#else // Not an i386 host
334  void X86CompilationCallback() {
335    llvm_unreachable("Cannot call X86CompilationCallback() on a non-x86 arch!");
336  }
337#endif
338}
339
340/// X86CompilationCallback2 - This is the target-specific function invoked by the
341/// function stub when we did not know the real target of a call.  This function
342/// must locate the start of the stub or call site and pass it into the JIT
343/// compiler function.
344extern "C" {
345#if !(defined (X86_64_JIT) && defined(_MSC_VER))
346 // the following function is called only from this translation unit,
347 // unless we are under 64bit Windows with MSC, where there is
348 // no support for inline assembly
349static
350#endif
351void LLVM_ATTRIBUTE_USED
352X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
353  intptr_t *RetAddrLoc = &StackPtr[1];
354  assert(*RetAddrLoc == RetAddr &&
355         "Could not find return address on the stack!");
356
357  // It's a stub if there is an interrupt marker after the call.
358  bool isStub = ((unsigned char*)RetAddr)[0] == 0xCE;
359
360  // The call instruction should have pushed the return value onto the stack...
361#if defined (X86_64_JIT)
362  RetAddr--;     // Backtrack to the reference itself...
363#else
364  RetAddr -= 4;  // Backtrack to the reference itself...
365#endif
366
367#if 0
368  DEBUG(dbgs() << "In callback! Addr=" << (void*)RetAddr
369               << " ESP=" << (void*)StackPtr
370               << ": Resolving call to function: "
371               << TheVM->getFunctionReferencedName((void*)RetAddr) << "\n");
372#endif
373
374  // Sanity check to make sure this really is a call instruction.
375#if defined (X86_64_JIT)
376  assert(((unsigned char*)RetAddr)[-2] == 0x41 &&"Not a call instr!");
377  assert(((unsigned char*)RetAddr)[-1] == 0xFF &&"Not a call instr!");
378#else
379  assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
380#endif
381
382  intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
383
384  // Rewrite the call target... so that we don't end up here every time we
385  // execute the call.
386#if defined (X86_64_JIT)
387  assert(isStub &&
388         "X86-64 doesn't support rewriting non-stub lazy compilation calls:"
389         " the call instruction varies too much.");
390#else
391  *(intptr_t *)RetAddr = (intptr_t)(NewVal-RetAddr-4);
392#endif
393
394  if (isStub) {
395    // If this is a stub, rewrite the call into an unconditional branch
396    // instruction so that two return addresses are not pushed onto the stack
397    // when the requested function finally gets called.  This also makes the
398    // 0xCE byte (interrupt) dead, so the marker doesn't effect anything.
399#if defined (X86_64_JIT)
400    // If the target address is within 32-bit range of the stub, use a
401    // PC-relative branch instead of loading the actual address.  (This is
402    // considerably shorter than the 64-bit immediate load already there.)
403    // We assume here intptr_t is 64 bits.
404    intptr_t diff = NewVal-RetAddr+7;
405    if (diff >= -2147483648LL && diff <= 2147483647LL) {
406      *(unsigned char*)(RetAddr-0xc) = 0xE9;
407      *(intptr_t *)(RetAddr-0xb) = diff & 0xffffffff;
408    } else {
409      *(intptr_t *)(RetAddr - 0xa) = NewVal;
410      ((unsigned char*)RetAddr)[0] = (2 | (4 << 3) | (3 << 6));
411    }
412    sys::ValgrindDiscardTranslations((void*)(RetAddr-0xc), 0xd);
413#else
414    ((unsigned char*)RetAddr)[-1] = 0xE9;
415    sys::ValgrindDiscardTranslations((void*)(RetAddr-1), 5);
416#endif
417  }
418
419  // Change the return address to reexecute the call instruction...
420#if defined (X86_64_JIT)
421  *RetAddrLoc -= 0xd;
422#else
423  *RetAddrLoc -= 5;
424#endif
425}
426}
427
428TargetJITInfo::LazyResolverFn
429X86JITInfo::getLazyResolverFunction(JITCompilerFn F) {
430  TsanIgnoreWritesBegin();
431  JITCompilerFunction = F;
432  TsanIgnoreWritesEnd();
433
434#if defined (X86_32_JIT) && !defined (_MSC_VER)
435  if (Subtarget->hasSSE1())
436    return X86CompilationCallback_SSE;
437#endif
438
439  return X86CompilationCallback;
440}
441
442X86JITInfo::X86JITInfo(X86TargetMachine &tm) : TM(tm) {
443  Subtarget = &TM.getSubtarget<X86Subtarget>();
444  useGOT = 0;
445  TLSOffset = 0;
446}
447
448void *X86JITInfo::emitGlobalValueIndirectSym(const GlobalValue* GV, void *ptr,
449                                             JITCodeEmitter &JCE) {
450#if defined (X86_64_JIT)
451  const unsigned Alignment = 8;
452  uint8_t Buffer[8];
453  uint8_t *Cur = Buffer;
454  MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(intptr_t)ptr);
455  MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(((intptr_t)ptr) >> 32));
456#else
457  const unsigned Alignment = 4;
458  uint8_t Buffer[4];
459  uint8_t *Cur = Buffer;
460  MachineCodeEmitter::emitWordLEInto(Cur, (intptr_t)ptr);
461#endif
462  return JCE.allocIndirectGV(GV, Buffer, sizeof(Buffer), Alignment);
463}
464
465TargetJITInfo::StubLayout X86JITInfo::getStubLayout() {
466  // The 64-bit stub contains:
467  //   movabs r10 <- 8-byte-target-address  # 10 bytes
468  //   call|jmp *r10  # 3 bytes
469  // The 32-bit stub contains a 5-byte call|jmp.
470  // If the stub is a call to the compilation callback, an extra byte is added
471  // to mark it as a stub.
472  StubLayout Result = {14, 4};
473  return Result;
474}
475
476void *X86JITInfo::emitFunctionStub(const Function* F, void *Target,
477                                   JITCodeEmitter &JCE) {
478  // Note, we cast to intptr_t here to silence a -pedantic warning that
479  // complains about casting a function pointer to a normal pointer.
480#if defined (X86_32_JIT) && !defined (_MSC_VER)
481  bool NotCC = (Target != (void*)(intptr_t)X86CompilationCallback &&
482                Target != (void*)(intptr_t)X86CompilationCallback_SSE);
483#else
484  bool NotCC = Target != (void*)(intptr_t)X86CompilationCallback;
485#endif
486  JCE.emitAlignment(4);
487  void *Result = (void*)JCE.getCurrentPCValue();
488  if (NotCC) {
489#if defined (X86_64_JIT)
490    JCE.emitByte(0x49);          // REX prefix
491    JCE.emitByte(0xB8+2);        // movabsq r10
492    JCE.emitWordLE((unsigned)(intptr_t)Target);
493    JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
494    JCE.emitByte(0x41);          // REX prefix
495    JCE.emitByte(0xFF);          // jmpq *r10
496    JCE.emitByte(2 | (4 << 3) | (3 << 6));
497#else
498    JCE.emitByte(0xE9);
499    JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
500#endif
501    return Result;
502  }
503
504#if defined (X86_64_JIT)
505  JCE.emitByte(0x49);          // REX prefix
506  JCE.emitByte(0xB8+2);        // movabsq r10
507  JCE.emitWordLE((unsigned)(intptr_t)Target);
508  JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
509  JCE.emitByte(0x41);          // REX prefix
510  JCE.emitByte(0xFF);          // callq *r10
511  JCE.emitByte(2 | (2 << 3) | (3 << 6));
512#else
513  JCE.emitByte(0xE8);   // Call with 32 bit pc-rel destination...
514
515  JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
516#endif
517
518  // This used to use 0xCD, but that value is used by JITMemoryManager to
519  // initialize the buffer with garbage, which means it may follow a
520  // noreturn function call, confusing X86CompilationCallback2.  PR 4929.
521  JCE.emitByte(0xCE);   // Interrupt - Just a marker identifying the stub!
522  return Result;
523}
524
525/// getPICJumpTableEntry - Returns the value of the jumptable entry for the
526/// specific basic block.
527uintptr_t X86JITInfo::getPICJumpTableEntry(uintptr_t BB, uintptr_t Entry) {
528#if defined(X86_64_JIT)
529  return BB - Entry;
530#else
531  return BB - PICBase;
532#endif
533}
534
535template<typename T> static void addUnaligned(void *Pos, T Delta) {
536  T Value;
537  std::memcpy(reinterpret_cast<char*>(&Value), reinterpret_cast<char*>(Pos),
538              sizeof(T));
539  Value += Delta;
540  std::memcpy(reinterpret_cast<char*>(Pos), reinterpret_cast<char*>(&Value),
541              sizeof(T));
542}
543
544/// relocate - Before the JIT can run a block of code that has been emitted,
545/// it must rewrite the code to contain the actual addresses of any
546/// referenced global symbols.
547void X86JITInfo::relocate(void *Function, MachineRelocation *MR,
548                          unsigned NumRelocs, unsigned char* GOTBase) {
549  for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
550    void *RelocPos = (char*)Function + MR->getMachineCodeOffset();
551    intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
552    switch ((X86::RelocationType)MR->getRelocationType()) {
553    case X86::reloc_pcrel_word: {
554      // PC relative relocation, add the relocated value to the value already in
555      // memory, after we adjust it for where the PC is.
556      ResultPtr = ResultPtr -(intptr_t)RelocPos - 4 - MR->getConstantVal();
557      addUnaligned<unsigned>(RelocPos, ResultPtr);
558      break;
559    }
560    case X86::reloc_picrel_word: {
561      // PIC base relative relocation, add the relocated value to the value
562      // already in memory, after we adjust it for where the PIC base is.
563      ResultPtr = ResultPtr - ((intptr_t)Function + MR->getConstantVal());
564      addUnaligned<unsigned>(RelocPos, ResultPtr);
565      break;
566    }
567    case X86::reloc_absolute_word:
568    case X86::reloc_absolute_word_sext:
569      // Absolute relocation, just add the relocated value to the value already
570      // in memory.
571      addUnaligned<unsigned>(RelocPos, ResultPtr);
572      break;
573    case X86::reloc_absolute_dword:
574      addUnaligned<intptr_t>(RelocPos, ResultPtr);
575      break;
576    }
577  }
578}
579
580char* X86JITInfo::allocateThreadLocalMemory(size_t size) {
581#if defined(X86_32_JIT) && !defined(__APPLE__) && !defined(_MSC_VER)
582  TLSOffset -= size;
583  return TLSOffset;
584#else
585  llvm_unreachable("Cannot allocate thread local storage on this arch!");
586#endif
587}
588