예제 #1
0
TCA emitEndCatchHelper(CodeBlock& cb, UniqueStubs& us) {
  auto const udrspo = rvmtl()[unwinderDebuggerReturnSPOff()];

  auto const debuggerReturn = vwrap(cb, [&] (Vout& v) {
    v << load{udrspo, rvmsp()};
    v << storeqi{0, udrspo};
  });
  svcreq::emit_persistent(cb, folly::none, REQ_POST_DEBUGGER_RET);

  auto const resumeCPPUnwind = vwrap(cb, [] (Vout& v) {
    static_assert(sizeof(tl_regState) == 1,
                  "The following store must match the size of tl_regState.");
    auto const regstate = emitTLSAddr(v, tls_datum(tl_regState));
    v << storebi{static_cast<int32_t>(VMRegState::CLEAN), regstate};

    v << load{rvmtl()[unwinderExnOff()], rarg(0)};
    v << call{TCA(_Unwind_Resume), arg_regs(1)};
  });
  us.endCatchHelperPast = cb.frontier();
  vwrap(cb, [] (Vout& v) { v << ud2{}; });

  alignJmpTarget(cb);

  return vwrap(cb, [&] (Vout& v) {
    auto const done1 = v.makeBlock();
    auto const sf1 = v.makeReg();

    v << cmpqim{0, udrspo, sf1};
    v << jcci{CC_NE, sf1, done1, debuggerReturn};
    v = done1;

    // Normal end catch situation: call back to tc_unwind_resume, which returns
    // the catch trace (or null) in %rax, and the new vmfp in %rdx.
    v << copy{rvmfp(), rarg(0)};
    v << call{TCA(tc_unwind_resume)};
    v << copy{reg::rdx, rvmfp()};

    auto const done2 = v.makeBlock();
    auto const sf2 = v.makeReg();

    v << testq{reg::rax, reg::rax, sf2};
    v << jcci{CC_Z, sf2, done2, resumeCPPUnwind};
    v = done2;

    // We need to do a syncForLLVMCatch(), but vmfp is already in rdx.
    v << jmpr{reg::rax};
  });
}
예제 #2
0
TCA emitFunctionEnterHelper(CodeBlock& cb, UniqueStubs& us) {
  alignJmpTarget(cb);

  auto const start = vwrap(cb, [&] (Vout& v) {
    auto const ar = v.makeReg();

    v << copy{rvmfp(), ar};

    // Fully set up the call frame for the stub.  We can't skip this like we do
    // in other stubs because we need the return IP for this frame in the %rbp
    // chain, in order to find the proper fixup for the VMRegAnchor in the
    // intercept handler.
    v << stublogue{true};
    v << copy{rsp(), rvmfp()};

    // When we call the event hook, it might tell us to skip the callee
    // (because of fb_intercept).  If that happens, we need to return to the
    // caller, but the handler will have already popped the callee's frame.
    // So, we need to save these values for later.
    v << pushm{ar[AROFF(m_savedRip)]};
    v << pushm{ar[AROFF(m_sfp)]};

    v << copy2{ar, v.cns(EventHook::NormalFunc), rarg(0), rarg(1)};

    bool (*hook)(const ActRec*, int) = &EventHook::onFunctionCall;
    v << call{TCA(hook)};
  });

  us.functionEnterHelperReturn = vwrap2(cb, [&] (Vout& v, Vout& vcold) {
    auto const sf = v.makeReg();
    v << testb{rret(), rret(), sf};

    unlikelyIfThen(v, vcold, CC_Z, sf, [&] (Vout& v) {
      auto const saved_rip = v.makeReg();

      // The event hook has already cleaned up the stack and popped the
      // callee's frame, so we're ready to continue from the original call
      // site.  We just need to grab the fp/rip of the original frame that we
      // saved earlier, and sync rvmsp().
      v << pop{rvmfp()};
      v << pop{saved_rip};

      // Drop our call frame; the stublogue{} instruction guarantees that this
      // is exactly 16 bytes.
      v << lea{rsp()[16], rsp()};

      // Sync vmsp and return to the caller.  This unbalances the return stack
      // buffer, but if we're intercepting, we probably don't care.
      v << load{rvmtl()[rds::kVmspOff], rvmsp()};
      v << jmpr{saved_rip};
    });

    // Skip past the stuff we saved for the intercept case.
    v << lea{rsp()[16], rsp()};

    // Restore rvmfp() and return to the callee's func prologue.
    v << stubret{RegSet(), true};
  });

  return start;
}
예제 #3
0
TCA emitFreeLocalsHelpers(CodeBlock& cb, DataBlock& data, UniqueStubs& us) {
  // The address of the first local is passed in the second argument register.
  // We use the third and fourth as scratch registers.
  auto const local = rarg(1);
  auto const last = rarg(2);
  auto const type = rarg(3);
  CGMeta fixups;

  // This stub is very hot; keep it cache-aligned.
  align(cb, &fixups, Alignment::CacheLine, AlignContext::Dead);
  auto const release =
    emitDecRefHelper(cb, data, fixups, local, type, local | last);

  auto const decref_local = [&] (Vout& v) {
    auto const sf = v.makeReg();

    // We can't do a byte load here---we have to sign-extend since we use
    // `type' as a 32-bit array index to the destructor table.
    v << loadzbl{local[TVOFF(m_type)], type};
    emitCmpTVType(v, sf, KindOfRefCountThreshold, type);

    ifThen(v, CC_G, sf, [&] (Vout& v) {
      auto const dword_size = sizeof(int64_t);

      // saving return value on the stack, but keeping it 16-byte aligned
      v << mflr{rfuncln()};
      v << lea {rsp()[-2 * dword_size], rsp()};
      v << store{rfuncln(), rsp()[0]};

      v << call{release, arg_regs(3)};

      // restore the return value from the stack
      v << load{rsp()[0], rfuncln()};
      v << lea {rsp()[2 * dword_size], rsp()};
      v << mtlr{rfuncln()};
    });
  };

  auto const next_local = [&] (Vout& v) {
    v << addqi{static_cast<int>(sizeof(TypedValue)),
               local, local, v.makeReg()};
  };

  alignJmpTarget(cb);

  us.freeManyLocalsHelper = vwrap(cb, data, fixups, [&] (Vout& v) {
    // We always unroll the final `kNumFreeLocalsHelpers' decrefs, so only loop
    // until we hit that point.
    v << lea{rvmfp()[localOffset(kNumFreeLocalsHelpers - 1)], last};

    doWhile(v, CC_NZ, {},
      [&] (const VregList& in, const VregList& out) {
        auto const sf = v.makeReg();

        decref_local(v);
        next_local(v);
        v << cmpq{local, last, sf};
        return sf;
      }
    );
  });

  for (auto i = kNumFreeLocalsHelpers - 1; i >= 0; --i) {
    us.freeLocalsHelpers[i] = vwrap(cb, data, [&] (Vout& v) {
      decref_local(v);
      if (i != 0) next_local(v);
    });
  }

  // All the stub entrypoints share the same ret.
  vwrap(cb, data, fixups, [] (Vout& v) { v << ret{}; });

  // This stub is hot, so make sure to keep it small.
#if 0
  // TODO(gut): Currently this assert fails.
  // Take a closer look when looking at performance
  always_assert(Stats::enabled() ||
                (cb.frontier() - release <= 4 * cache_line_size()));
#endif

  fixups.process(nullptr);
  return release;
}
예제 #4
0
TCA emitFreeLocalsHelpers(CodeBlock& cb, UniqueStubs& us) {
  // The address of the first local is passed in the second argument register.
  // We use the third and fourth as scratch registers.
  auto const local = rarg(1);
  auto const last = rarg(2);
  auto const type = rarg(3);
  CGMeta fixups;

  // This stub is very hot; keep it cache-aligned.
  align(cb, &fixups, Alignment::CacheLine, AlignContext::Dead);
  auto const release = emitDecRefHelper(cb, fixups, local, type, local | last);

  auto const decref_local = [&] (Vout& v) {
    auto const sf = v.makeReg();

    // We can't do a byte load here---we have to sign-extend since we use
    // `type' as a 32-bit array index to the destructor table.
    v << loadzbl{local[TVOFF(m_type)], type};
    emitCmpTVType(v, sf, KindOfRefCountThreshold, type);

    ifThen(v, CC_G, sf, [&] (Vout& v) {
      v << call{release, arg_regs(3)};
    });
  };

  auto const next_local = [&] (Vout& v) {
    v << addqi{static_cast<int>(sizeof(TypedValue)),
               local, local, v.makeReg()};
  };

  alignJmpTarget(cb);

  us.freeManyLocalsHelper = vwrap(cb, fixups, [&] (Vout& v) {
    // We always unroll the final `kNumFreeLocalsHelpers' decrefs, so only loop
    // until we hit that point.
    v << lea{rvmfp()[localOffset(kNumFreeLocalsHelpers - 1)], last};

    doWhile(v, CC_NZ, {},
      [&] (const VregList& in, const VregList& out) {
        auto const sf = v.makeReg();

        decref_local(v);
        next_local(v);
        v << cmpq{local, last, sf};
        return sf;
      }
    );
  });

  for (auto i = kNumFreeLocalsHelpers - 1; i >= 0; --i) {
    us.freeLocalsHelpers[i] = vwrap(cb, [&] (Vout& v) {
      decref_local(v);
      if (i != 0) next_local(v);
    });
  }

  // All the stub entrypoints share the same ret.
  vwrap(cb, fixups, [] (Vout& v) { v << ret{}; });

  // This stub is hot, so make sure to keep it small.
  // Alas, we have more work to do in this under Windows,
  // so we can't be this small :(
#ifndef _WIN32
  always_assert(Stats::enabled() ||
                (cb.frontier() - release <= 4 * x64::cache_line_size()));
#endif

  fixups.process(nullptr);
  return release;
}
예제 #5
0
TCA emitFreeLocalsHelpers(CodeBlock& cb, DataBlock& data, UniqueStubs& us) {
  // The address of the first local is passed in the second argument register.
  // We use the third and fourth as scratch registers.
  auto const local = rarg(1);
  auto const last = rarg(2);
  auto const type = rarg(3);
  CGMeta fixups;
  TCA freeLocalsHelpers[kNumFreeLocalsHelpers];
  TCA freeManyLocalsHelper;

  // This stub is very hot; keep it cache-aligned.
  align(cb, &fixups, Alignment::CacheLine, AlignContext::Dead);
  auto const release =
    emitDecRefHelper(cb, data, fixups, local, type, local | last);

  auto const decref_local = [&] (Vout& v) {
    auto const sf = v.makeReg();

    // We can't use emitLoadTVType() here because it does a byte load, and we
    // need to sign-extend since we use `type' as a 32-bit array index to the
    // destructor table.
    v << loadzbl{local[TVOFF(m_type)], type};
    emitCmpTVType(v, sf, KindOfRefCountThreshold, type);

    ifThen(v, CC_G, sf, [&] (Vout& v) {
      v << call{release, arg_regs(3)};
    });
  };

  auto const next_local = [&] (Vout& v) {
    v << addqi{static_cast<int>(sizeof(TypedValue)),
               local, local, v.makeReg()};
  };

  alignJmpTarget(cb);

  freeManyLocalsHelper = vwrap(cb, data, [&] (Vout& v) {
    // We always unroll the final `kNumFreeLocalsHelpers' decrefs, so only loop
    // until we hit that point.
    v << lea{rvmfp()[localOffset(kNumFreeLocalsHelpers - 1)], last};

    // Set up frame linkage to avoid an indirect fixup.
    v << copy{rsp(), rfp()};

    doWhile(v, CC_NZ, {},
      [&] (const VregList& in, const VregList& out) {
        auto const sf = v.makeReg();

        decref_local(v);
        next_local(v);
        v << cmpq{local, last, sf};
        return sf;
      }
    );
  });

  for (auto i = kNumFreeLocalsHelpers - 1; i >= 0; --i) {
    freeLocalsHelpers[i] = vwrap(cb, data, [&] (Vout& v) {
      decref_local(v);
      if (i != 0) next_local(v);
    });
  }

  // All the stub entrypoints share the same ret.
  vwrap(cb, data, fixups, [] (Vout& v) {
    v << popp{rfp(), rlr()};
    v << ret{};
  });

  // Create a table of branches
  us.freeManyLocalsHelper = vwrap(cb, data, [&] (Vout& v) {
    v << pushp{rlr(), rfp()};

    // rvmfp() is needed by the freeManyLocalsHelper stub above, so frame
    // linkage setup is deferred until after its use in freeManyLocalsHelper.
    v << jmpi{freeManyLocalsHelper};
  });
  for (auto i = kNumFreeLocalsHelpers - 1; i >= 0; --i) {
    us.freeLocalsHelpers[i] = vwrap(cb, data, [&] (Vout& v) {
      // We set up frame linkage to avoid an indirect fixup.
      v << pushp{rlr(), rfp()};
      v << copy{rsp(), rfp()};
      v << jmpi{freeLocalsHelpers[i]};
    });
  }

  // FIXME: This stub is hot, so make sure to keep it small.
#if 0
  always_assert(Stats::enabled() ||
                (cb.frontier() - release <= 4 * x64::cache_line_size()));
#endif

  fixups.process(nullptr);
  return release;
}