hphp/runtime/vm/jit/service-requests.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   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 #pragma once
  18
  19 #include "hphp/runtime/vm/srckey.h"
  20
  21 #include "hphp/runtime/vm/jit/types.h"
  22 #include "hphp/runtime/vm/jit/containers.h"
  23 #include "hphp/runtime/vm/jit/stack-offsets.h"
  24
  25 #include "hphp/util/asm-x64.h"
  26 #include "hphp/util/data-block.h"
  27
  28 namespace HPHP {
  29
  30 struct ActRec;
  31
  32 namespace jit {
  33
  34 struct CGMeta;
  35
  36 ///////////////////////////////////////////////////////////////////////////////
  37
  38 namespace svcreq {
  39
  40 ///////////////////////////////////////////////////////////////////////////////
  41
  42 /*
  43  * A service request stub is a tiny routine used to invoke JIT translation
  44  * services, used in place of the actual translation. Incoming branches to
  45  * service request stubs are smashable and tracked by SrcDB.
  46  *
  47  * Stubs, first, set up enough context to reconstruct the SrcKey and stack
  48  * positions, then, jump to the corresponding unique stub to perform the
  49  * requested operation.
  50  */
  51 enum class StubType : uint8_t {
  52   // A request to translate the code at the given current location.
  53   // See svcreq::handleTranslate() for more details.
  54   Translate,
  55
  56   // A request to retranslate the code at the given current location.
  57   // See svcreq::handleRetranslate() for more details.
  58   Retranslate,
  59 };
  60
  61 /*
  62  * Get an existing stub or emit a new one to perform request of the given type
  63  * at the given code and stack position. The same stub may be compatible with
  64  * multiple different positions.
  65  *
  66  * Returns nullptr on failure, e.g. when there is no more TC space available.
  67  */
  68 TCA getOrEmitStub(StubType type, SrcKey sk, SBInvOffset spOff);
  69
  70 ///////////////////////////////////////////////////////////////////////////////
  71 // Emitters.
  72
  73 /*
  74  * Emit a stub which syncs vmsp and vmpc and then calls
  75  * interpHelperNoTranslateFromTC. Call are smashed to this when we know we
  76  * can no longer create new translations. The address of the stub is
  77  * returned if successful, nullptr otherwise (the creation can fail if
  78  * there's no space in the TC for it).
  79  */
  80 TCA emit_interp_no_translate_stub(SBInvOffset spOff, SrcKey sk);
  81
  82 ///////////////////////////////////////////////////////////////////////////////
  83
  84 }}}