src/sim/guest_abi/dispatch.hh

   1 /*
   2  * Copyright 2019 Google Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met: redistributions of source code must retain the above copyright
   7  * notice, this list of conditions and the following disclaimer;
   8  * redistributions in binary form must reproduce the above copyright
   9  * notice, this list of conditions and the following disclaimer in the
  10  * documentation and/or other materials provided with the distribution;
  11  * neither the name of the copyright holders nor the names of its
  12  * contributors may be used to endorse or promote products derived from
  13  * this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  18  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  19  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  21  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #ifndef __SIM_GUEST_ABI_DISPATCH_HH__
  29 #define __SIM_GUEST_ABI_DISPATCH_HH__
  30
  31 #include <functional>
  32 #include <sstream>
  33 #include <type_traits>
  34
  35 #include "sim/guest_abi/definition.hh"
  36 #include "sim/guest_abi/layout.hh"
  37
  38 class ThreadContext;
  39
  40 namespace GuestABI
  41 {
  42
  43 /*
  44  * These functions will likely be common among all ABIs and implement the
  45  * mechanism of gathering arguments, calling the target function, and then
  46  * storing the result. They might need to be overridden if, for instance,
  47  * the location of arguments need to be determined in a different order.
  48  * For example, there might be an ABI which gathers arguments starting
  49  * from the last in the list instead of the first. This is unlikely but
  50  * still possible to support by redefining these functions..
  51  */
  52
  53 // With no arguments to gather, call the target function and store the
  54 // result.
  55 template <typename ABI, typename Ret>
  56 static typename std::enable_if<!std::is_void<Ret>::value, Ret>::type
  57 callFrom(ThreadContext *tc, typename ABI::State &state,
  58         std::function<Ret(ThreadContext *)> target)
  59 {
  60     Ret ret = target(tc);
  61     storeResult<ABI, Ret>(tc, ret, state);
  62     return ret;
  63 }
  64
  65 // With no arguments to gather and nothing to return, call the target function.
  66 template <typename ABI>
  67 static void
  68 callFrom(ThreadContext *tc, typename ABI::State &state,
  69         std::function<void(ThreadContext *)> target)
  70 {
  71     target(tc);
  72 }
  73
  74 // Recursively gather arguments for target from tc until we get to the base
  75 // case above.
  76 template <typename ABI, typename Ret, typename NextArg, typename ...Args>
  77 static typename std::enable_if<!std::is_void<Ret>::value, Ret>::type
  78 callFrom(ThreadContext *tc, typename ABI::State &state,
  79         std::function<Ret(ThreadContext *, NextArg, Args...)> target)
  80 {
  81     // Extract the next argument from the thread context.
  82     NextArg next = getArgument<ABI, NextArg>(tc, state);
  83
  84     // Build a partial function which adds the next argument to the call.
  85     std::function<Ret(ThreadContext *, Args...)> partial =
  86         [target,next](ThreadContext *_tc, Args... args) {
  87             return target(_tc, next, args...);
  88         };
  89
  90     // Recursively handle any remaining arguments.
  91     return callFrom<ABI, Ret, Args...>(tc, state, partial);
  92 }
  93
  94 // Recursively gather arguments for target from tc until we get to the base
  95 // case above. This version is for functions that don't return anything.
  96 template <typename ABI, typename NextArg, typename ...Args>
  97 static void
  98 callFrom(ThreadContext *tc, typename ABI::State &state,
  99         std::function<void(ThreadContext *, NextArg, Args...)> target)
 100 {
 101     // Extract the next argument from the thread context.
 102     NextArg next = getArgument<ABI, NextArg>(tc, state);
 103
 104     // Build a partial function which adds the next argument to the call.
 105     std::function<void(ThreadContext *, Args...)> partial =
 106         [target,next](ThreadContext *_tc, Args... args) {
 107             target(_tc, next, args...);
 108         };
 109
 110     // Recursively handle any remaining arguments.
 111     callFrom<ABI, Args...>(tc, state, partial);
 112 }
 113
 114
 115
 116 /*
 117  * These functions are like the ones above, except they print the arguments
 118  * a target function would be called with instead of actually calling it.
 119  */
 120
 121 // With no arguments to print, add the closing parenthesis and return.
 122 template <typename ABI, typename Ret>
 123 static void
 124 dumpArgsFrom(int count, std::ostream &os, ThreadContext *tc,
 125              typename ABI::State &state)
 126 {
 127     os << ")";
 128 }
 129
 130 // Recursively gather arguments for target from tc until we get to the base
 131 // case above, and append those arguments to the string stream being
 132 // constructed.
 133 template <typename ABI, typename Ret, typename NextArg, typename ...Args>
 134 static void
 135 dumpArgsFrom(int count, std::ostream &os, ThreadContext *tc,
 136              typename ABI::State &state)
 137 {
 138     // Either open the parenthesis or add a comma, depending on where we are
 139     // in the argument list.
 140     os << (count ? ", " : "(");
 141
 142     // Extract the next argument from the thread context.
 143     NextArg next = getArgument<ABI, NextArg>(tc, state);
 144
 145     // Add this argument to the list.
 146     os << next;
 147
 148     // Recursively handle any remaining arguments.
 149     dumpArgsFrom<ABI, Ret, Args...>(count + 1, os, tc, state);
 150 }
 151
 152 } // namespace GuestABI
 153
 154 #endif // __SIM_GUEST_ABI_DISPATCH_HH__