docs/sources/mono-api-dynamic-codegen.html

   1 <h2>Dynamic Code Generation</h2>
   2
   3         <p>The dynamic code generation interface inside the Mono
   4         runtime is similar to the API exposed by
   5         System.Reflection.Emit.
   6
   7         <p>This interface is used by Mono internally to generate code
   8         on the flight in a cross-platform fashion.  For example,
   9         P/Invoke marshalling in Mono is implemented in terms of this
  10         interface, but it is also used in various other parts of the
  11         runtime.
  12
  13         <p>Unlike Reflection.Emit, the dynamic code generation
  14         interface does not start with an assembly builder.   The code
  15         generation interface starts directly at the method level,
  16         which is represented by a pointer to the MonoMethodBuilder
  17         structure.
  18
  19         <p>To JIT this method, the process is this:
  20
  21         <ul>
  22                 <li>Create a <tt>MonoMethodBuilder</tt> object using
  23                 the <tt>mono_mb_new</tt> method.  The method's class
  24                 is specified as the first argument.
  25
  26                 <li>Create the method signature, using
  27                 <tt>mono_metadata_signature_alloc</tt>.  The call
  28                 takes the number of arguments that the method takes.
  29                 Then you must initialize the types for each one of the
  30                 parameters.
  31
  32                 <li>Emit the CIL code, using one of the
  33                 <tt>mono_mb_emit_*</tt> functions.   There are some
  34                 helper routines that you can use.
  35
  36                 <li>Create the <tt>MonoMethod</tt> from the
  37                 <tt>MethodBuilder</tt> using
  38                 <tt>mono_mb_create_method</tt>.
  39
  40                 <li>Release the <tt>MonoMethodBuilder</tt> resources
  41                 using mono_mb_free.
  42         </ul>
  43
  44         <p>The result of this process is a <tt>MonoMethod</tt> which
  45         can be called using <tt><a
  46         href="api:mono_create_jit_trampoline">mono_create_jit_trampoline</a></tt>
  47         routine or can be passed to any other functions that require
  48         the MonoMethod.
  49
  50         <p>Example:
  51
  52         <pre>
  53 MonoMethod *adder ()
  54 {
  55     MonoMethodBuilder *mb;
  56     MonoMethodSignature *sig;
  57     MonoMethod *method;
  58
  59     mb = mono_mb_new (mono_defaults.object_class, "adder", MONO_WRAPPER_NONE);
  60
  61     /* Setup method signature */
  62     sig = mono_metadata_signature_alloc (2);
  63     sig->ret = &amp;mono_get_int32_class ()->byval_arg;
  64     sig->params [0] = &amp;mono_get_int32_class ()->byval_arg;
  65     sig->params [1] = &amp;mono_defaults.int32_class->byval_arg;
  66
  67     /* Emit CIL code */
  68     mono_mb_emit_ldarg (mb, 0);
  69     mono_mb_emit_ldarg (mb, 1);
  70     mono_mb_emit_byte (mb, CEE_ADD);
  71     mono_mb_emit_byte (mb, CEE_RET);
  72
  73     /* Get the method */
  74     method = mono_mb_create_method (mb, sig, max_stack);
  75
  76     /* Cleanup */
  77     mono_mb-free (mb);
  78     return method;
  79 }
  80         </pre>
  81
  82 <h4><a name="api:mono_mb_new">mono_mb_new</a></h4>
  83
  84         <p>The possible values for the <i>type</i> argument are:
  85
  86 <pre>
  87         MONO_WRAPPER_NONE
  88         MONO_WRAPPER_DELEGATE_INVOKE
  89         MONO_WRAPPER_DELEGATE_BEGIN_INVOKE
  90         MONO_WRAPPER_DELEGATE_END_INVOKE
  91         MONO_WRAPPER_RUNTIME_INVOKE
  92         MONO_WRAPPER_NATIVE_TO_MANAGED
  93         MONO_WRAPPER_MANAGED_TO_NATIVE
  94         MONO_WRAPPER_REMOTING_INVOKE
  95         MONO_WRAPPER_REMOTING_INVOKE_WITH_CHECK
  96         MONO_WRAPPER_XDOMAIN_INVOKE
  97         MONO_WRAPPER_XDOMAIN_DISPATCH
  98         MONO_WRAPPER_LDFLD
  99         MONO_WRAPPER_STFLD
 100         MONO_WRAPPER_LDFLD_REMOTE
 101         MONO_WRAPPER_STFLD_REMOTE
 102         MONO_WRAPPER_SYNCHRONIZED
 103         MONO_WRAPPER_DYNAMIC_METHOD
 104         MONO_WRAPPER_ISINST
 105         MONO_WRAPPER_CASTCLASS
 106         MONO_WRAPPER_PROXY_ISINST
 107         MONO_WRAPPER_STELEMREF
 108         MONO_WRAPPER_UNBOX
 109         MONO_WRAPPER_LDFLDA
 110         MONO_WRAPPER_UNKNOWN
 111 </pre>
 112
 113 <h3>Emitting IL</h3>
 114
 115         <p>Functions that can be used to generate IL on the flight,
 116         similar in spirit to System.Reflection.Emit.ILGenerator.
 117
 118 <h4><a name="api:mono_mb_emit_add_to_local">mono_mb_emit_add_to_local</a></h4>
 119 <h4><a name="api:mono_mb_emit_branch">mono_mb_emit_branch</a></h4>
 120 <h4><a name="api:mono_mb_emit_byte">mono_mb_emit_byte</a></h4>
 121 <h4><a name="api:mono_mb_emit_exception">mono_mb_emit_exception</a></h4>
 122 <h4><a name="api:mono_mb_emit_i2">mono_mb_emit_i2</a></h4>
 123 <h4><a name="api:mono_mb_emit_i4">mono_mb_emit_i4</a></h4>
 124 <h4><a name="api:mono_mb_emit_icon">mono_mb_emit_icon</a></h4>
 125 <h4><a name="api:mono_mb_emit_ldarg_addr">mono_mb_emit_ldarg_addr</a></h4>
 126 <h4><a name="api:mono_mb_emit_ldarg">mono_mb_emit_ldarg</a></h4>
 127 <h4><a name="api:mono_mb_emit_ldflda">mono_mb_emit_ldflda</a></h4>
 128 <h4><a name="api:mono_mb_emit_ldloc_addr">mono_mb_emit_ldloc_addr</a></h4>
 129 <h4><a name="api:mono_mb_emit_ldloc">mono_mb_emit_ldloc</a></h4>
 130 <h4><a name="api:mono_mb_emit_ldstr">mono_mb_emit_ldstr</a></h4>
 131 <h4><a name="api:mono_mb_emit_managed_call">mono_mb_emit_managed_call</a></h4>
 132 <h4><a name="api:mono_mb_emit_native_call">mono_mb_emit_native_call</a></h4>
 133 <h4><a name="api:mono_mb_emit_stloc">mono_mb_emit_stloc</a></h4>
 134
 135 <h3>Local variables and Methods</h3>
 136 <h4><a name="api:mono_mb_create_method">mono_mb_create_method</a></h4>
 137 <h4><a name="api:mono_mb_add_data">mono_mb_add_data</a></h4>
 138 <h4><a name="api:mono_mb_add_local">mono_mb_add_local</a></h4>
 139 <h4><a name="api:mono_mb_free">mono_mb_free</a></h4>
 140
 141 <h3>Patching Addresses</h3>
 142 <h4><a name="api:mono_mb_patch_addr">mono_mb_patch_addr</a></h4>
 143 <h4><a name="api:mono_mb_patch_addr_s">mono_mb_patch_addr_s</a></h4>
 144
 145 <h3>Method Signatures</h3>
 146 <h4><a name="api:mono_metadata_signature_alloc">mono_metadata_signature_alloc</a></h4>
 147 <h4><a name="api:mono_metadata_signature_dup">mono_metadata_signature_dup</a></h4>
 148 <h4><a name="api:mono_metadata_signature_equal">mono_metadata_signature_equal</a></h4>
 149
 150