hphp/runtime/vm/jit/func-guard-ppc64.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | (c) Copyright IBM Corporation 2015                                   |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #include "hphp/runtime/vm/jit/func-guard-ppc64.h"
  18
  19 #include "hphp/runtime/vm/jit/abi.h"
  20 #include "hphp/runtime/vm/jit/abi-ppc64.h"
  21 #include "hphp/runtime/vm/jit/mc-generator.h"
  22 #include "hphp/runtime/vm/jit/smashable-instr-ppc64.h"
  23 #include "hphp/runtime/vm/jit/unique-stubs.h"
  24
  25 #include "hphp/ppc64-asm/asm-ppc64.h"
  26 #include "hphp/util/data-block.h"
  27 #include "hphp/util/immed.h"
  28
  29 namespace HPHP { namespace jit { namespace ppc64 {
  30
  31 ///////////////////////////////////////////////////////////////////////////////
  32
  33 namespace {
  34
  35 ///////////////////////////////////////////////////////////////////////////////
  36
  37 constexpr auto kFuncGuardLen = 0x38;
  38
  39 ALWAYS_INLINE bool isPrologueStub(TCA addr) {
  40   return addr == mcg->ustubs().fcallHelperThunk;
  41 }
  42
  43 ///////////////////////////////////////////////////////////////////////////////
  44
  45 }
  46
  47 ///////////////////////////////////////////////////////////////////////////////
  48
  49 void emitFuncGuard(const Func* func, CodeBlock& cb, CGMeta& fixups) {
  50   ppc64_asm::Assembler a { cb };
  51
  52   const auto tmp1 = ppc64_asm::reg::r3;
  53   const auto tmp2 = ppc64_asm::reg::r4;
  54
  55   assertx(ppc64::abi(CodeKind::CrossTrace).gpUnreserved.contains(tmp1));
  56   assertx(ppc64::abi(CodeKind::CrossTrace).gpUnreserved.contains(tmp2));
  57
  58   emitSmashableMovq(a.code(), fixups, uint64_t(func), tmp1);
  59   a.  ld     (tmp2, rvmfp()[AROFF(m_func)]);
  60   a.  cmpld  (tmp1, tmp2);
  61
  62   a.  branchAuto(mcg->ustubs().funcPrologueRedispatch,
  63                   ppc64_asm::BranchConditions::NotEqual);
  64
  65   DEBUG_ONLY auto guard = funcGuardFromPrologue(a.frontier(), func);
  66   assertx(funcGuardMatches(guard, func));
  67 }
  68
  69 TCA funcGuardFromPrologue(TCA prologue, const Func* func) {
  70   if (isPrologueStub(prologue)) return prologue;
  71   return (prologue - kFuncGuardLen);
  72 }
  73
  74 bool funcGuardMatches(TCA guard, const Func* func) {
  75   if (isPrologueStub(guard)) return false;
  76
  77   auto const ifunc = reinterpret_cast<uintptr_t>(func);
  78   return static_cast<uintptr_t>(ppc64_asm::Assembler::getLi64(guard)) == ifunc;
  79 }
  80
  81 void clobberFuncGuard(TCA guard, const Func* func) {
  82   smashMovq(guard, 0);
  83 }
  84
  85 ///////////////////////////////////////////////////////////////////////////////
  86
  87 }}}