第二人生的源码分析(112)脚本的综合分析（2）

前面介绍了分析脚本类的声明，下面来仔细地分析它的实现代码，理解它的实现过程，也就理解了脚本代码的编译过程，如下：

返回生成的代码大小为 0.

#001 S32 LLScriptScript::getSize()

#002 {

#003 return 0;

#004 }

#005

脚本类的构造函数，主要进行初始化的工作。

#006 LLScriptScript::LLScriptScript(LLScritpGlobalStorage *globals,

#007 LLScriptState *states) :

#008 LLScriptFilePosition(0, 0),

#009 mStates(states), mGlobalScope(NULL), mGlobals(NULL), mGlobalFunctions(NULL), mGodLike(FALSE)

#010 {

设置缺省生成字节码的文件名称。

#011 const char DEFAULT_BYTECODE_FILENAME[] = "lscript.lso";

#012 strncpy(mBytecodeDest, DEFAULT_BYTECODE_FILENAME, sizeof(mBytecodeDest) -1); /*Flawfinder: ignore*/

#013 mBytecodeDest[MAX_STRING-1] = '/0';

下面开始分析全局变量和全局函数的保存位置。

#014 LLScriptGlobalVariable *tvar;

#015 LLScriptGlobalFunctions *tfunc;

#016 LLScritpGlobalStorage *temp;

#017

#018 temp = globals;

#019 while(temp)

#020 {

#021 if (temp->mbGlobalFunction)

#022 {

#023 if (!mGlobalFunctions)

#024 {

#025 mGlobalFunctions = (LLScriptGlobalFunctions *)temp->mGlobal;

#026 }

#027 else

#028 {

#029 tfunc = mGlobalFunctions;

#030 while(tfunc->mNextp)

#031 {

#032 tfunc = tfunc->mNextp;

#033 }

#034 tfunc->mNextp = (LLScriptGlobalFunctions *)temp->mGlobal;

#035 }

#036 }

#037 else

#038 {

#039 if (!mGlobals)

#040 {

#041 mGlobals = (LLScriptGlobalVariable *)temp->mGlobal;

#042 }

#043 else

#044 {

#045 tvar = mGlobals;

#046 while(tvar->mNextp)

#047 {

#048 tvar = tvar->mNextp;

#049 }

#050 tvar->mNextp = (LLScriptGlobalVariable *)temp->mGlobal;

#051 }

#052 }

#053 temp = temp->mNextp;

#054 }

#055 }

#056

这个函数主要实现设置字节码保存的文件名称。

#057 void LLScriptScript::setBytecodeDest(const char* dst_filename)

#058 {

#059 strncpy(mBytecodeDest, dst_filename, MAX_STRING); /*Flawfinder: ignore*/

#060 mBytecodeDest[MAX_STRING-1] = '/0';

#061 }

#062

#063 void print_cil_globals(FILE* fp, LLScriptGlobalVariable* global)

#064 {

#065 fprintf(fp, ".field private ");

#066 print_cil_type(fp, global->mType->mType);

#067 fprintf(fp, " ");

#068 fprintf(fp, global->mIdentifier->mName); /*Flawfinder: ignore*/

#069 fprintf(fp, "/n");

#070 if(NULL != global->mNextp)

#071 {

#072 print_cil_globals(fp, global->mNextp);

#073 }

#074 }

#075

开始递归处理所有脚本树。

#076 void LLScriptScript::recurse(FILE *fp, S32 tabs, S32 tabsize, LSCRIPTCompilePass pass, LSCRIPTPruneType ptype, BOOL &prunearg, LLScriptScope *scope, LSCRIPTType &type,

#077 LSCRIPTType basetype, U64 &count, LLScriptByteCodeChunk *chunk, LLScriptByteCodeChunk *heap, S32 stacksize, LLScriptScopeEntry *entry, S32 entrycount, LLScriptLibData **ldata)

#078 {

如果分析有出错，就不再处理。

#079 if (gErrorToText.getErrors())

#080 {

#081 return;

#082 }

根据不同的编译遍来作不同的树遍历处理。

#083 switch(pass)

#084 {

输出合适的说明文字。

#085 case LSCP_PRETTY_PRINT:

#086 if (mGlobals)

#087 {

#088 fdotabs(fp, tabs, tabsize);

#089 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#090 NULL);

#091 }

#092

#093 if (mGlobalFunctions)

#094 {

#095 fdotabs(fp, tabs, tabsize);

#096 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#097 entrycount, NULL);

#098 }

#099

#100 fdotabs(fp, tabs, tabsize);

#101 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#102 break;

进行代码优化，主要删除不需要的代码。

#103 case LSCP_PRUNE:

#104 if (mGlobalFunctions)

#105 {

#106 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#107 entrycount, NULL);

#108 }

#109 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#110 break;

全局的作用域检查。

#111 case LSCP_SCOPE_PASS1:

#112 {

#113 mGlobalScope = new LLScriptScope(gScopeStringTable);

#114 // zeroth, add library functions to global scope

#115 S32 i;

#116 char *arg;

#117 LLScriptScopeEntry *sentry;

#118 for (i = 0; i < gScriptLibrary.mNextNumber; i++)

#119 {

#120 // First, check to make sure this isn't a god only function, or that the viewer's agent is a god.

#121 if (!gScriptLibrary.mFunctions[i]->mGodOnly || mGodLike)

#122 {

#123 if (gScriptLibrary.mFunctions[i]->mReturnType)

#124 sentry = mGlobalScope->addEntry(gScriptLibrary.mFunctions[i]->mName,

#125 LIT_LIBRARY_FUNCTION, char2type(*gScriptLibrary.mFunctions[i]->mReturnType));

#126 else

#127 sentry = mGlobalScope->addEntry(gScriptLibrary.mFunctions[i]->mName,

#128 LIT_LIBRARY_FUNCTION, LST_NULL);

#129 sentry->mLibraryNumber = i;

#130 arg = gScriptLibrary.mFunctions[i]->mArgs;

#131 if (arg)

#132 {

#133 while (*arg)

#134 {

#135 sentry->mFunctionArgs.addType(char2type(*arg));

#136 sentry->mSize += LSCRIPTDataSize[char2type(*arg)];

#137 sentry->mOffset += LSCRIPTDataSize[char2type(*arg)];

#138 arg++;

#139 }

#140 }

#141 }

#142 }

#143 // first go and collect all the global variables

#144 if (mGlobals)

#145 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, mGlobalScope, type, basetype, count, chunk, heap,

#146 stacksize, entry, entrycount, NULL);

#147 // second, do the global functions

#148 if (mGlobalFunctions)

#149 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, mGlobalScope, type, basetype, count, chunk, heap,

#150 stacksize, entry, entrycount, NULL);

#151 // now do states

#152 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, mGlobalScope, type, basetype, count, chunk, heap, stacksize, entry,

#153 entrycount, NULL);

#154 break;

#155 }

第二次作用域检查，主要检查跳转、函数调用和状态转换。

#156 case LSCP_SCOPE_PASS2:

#157 // now we're checking jumps, function calls, and state transitions

#158 if (mGlobalFunctions)

#159 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, mGlobalScope, type, basetype, count, chunk, heap, stacksize, entry,

#160 entrycount, NULL);

#161 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, mGlobalScope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#162 break;

对脚本的类型进行检查。

#163 case LSCP_TYPE:

#164 // first we need to check global variables

#165 if (mGlobals)

#166 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#167 NULL);

#168 // now do global functions and states

#169 if (mGlobalFunctions)

#170 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#171 entrycount, NULL);

#172 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#173 break;

确定所有脚本需的资源大小。

#174 case LSCP_RESOURCE:

#175 // first determine resource counts for globals

#176 count = 0;

#177 if (mGlobals)

#178 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#179 NULL);

#180 // now do locals

#181 if (mGlobalFunctions)

#182 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#183 entrycount, NULL);

#184 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#185 break;

输出汇编代码。

#186 case LSCP_EMIT_ASSEMBLY:

#187

#188 if (mGlobals)

#189 {

#190 fprintf(fp, "GLOBALS/n");

#191 fdotabs(fp, tabs, tabsize);

#192 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#193 NULL);

#194 fprintf(fp, "/n");

#195 }

#196

#197 if (mGlobalFunctions)

#198 {

#199 fprintf(fp, "GLOBAL FUNCTIONS/n");

#200 fdotabs(fp, tabs, tabsize);

#201 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#202 entrycount, NULL);

#203 fprintf(fp, "/n");

#204 }

#205

#206 fprintf(fp, "STATES/n");

#207 fdotabs(fp, tabs, tabsize);

#208 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#209 fprintf(fp, "/n");

#210 break;

输出虚拟机可以运行的字节码。

#211 case LSCP_EMIT_BYTE_CODE:

#212 {

#213 // first, create data structure to hold the whole shebang

#214 LLScriptScriptCodeChunk *code = new LLScriptScriptCodeChunk(TOP_OF_MEMORY);

#215

#216 // ok, let's add the registers, all zeroes for now

#217 S32 i;

#218 S32 nooffset = 0;

#219

#220 for (i = LREG_IP; i < LREG_EOF; i++)

#221 {

#222 if (i < LREG_NCE)

#223 code->mRegisters->addBytes(4);

#224 else if (LSL2_CURRENT_MAJOR_VERSION == LSL2_MAJOR_VERSION_TWO)

#225 code->mRegisters->addBytes(8);

#226 }

#227 // global variables

#228 if (mGlobals)

#229 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, code->mGlobalVariables,

#230 code->mHeap, stacksize, entry, entrycount, NULL);

#231

#232 // put the ending heap block onto the heap

#233 U8 *temp;

#234 S32 size = lsa_create_data_block(&temp, NULL, 0);

#235 code->mHeap->addBytes(temp, size);

#236 delete [] temp;

#237

#238 // global functions

#239 // make space for global function jump table

#240 if (mGlobalFunctions)

#241 {

#242 code->mGlobalFunctions->addBytes(LSCRIPTDataSize[LST_INTEGER]*mGlobalScope->mFunctionCount +

#243 LSCRIPTDataSize[LST_INTEGER]);

#244 integer2bytestream(code->mGlobalFunctions->mCodeChunk, nooffset, mGlobalScope->mFunctionCount);

#245 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, code-

#246 >mGlobalFunctions, NULL, stacksize, entry, entrycount, NULL);

#247 }

#248

#249

#250 nooffset = 0;

#251 // states

#252 // make space for state jump/info table

#253 if (LSL2_CURRENT_MAJOR_VERSION == LSL2_MAJOR_VERSION_TWO)

#254 {

#255 code->mStates->addBytes(LSCRIPTDataSize[LST_INTEGER]*3*mGlobalScope->mStateCount + LSCRIPTDataSize

#256 [LST_INTEGER]);

#257 }

#258 else

#259 {

#260 code->mStates->addBytes(LSCRIPTDataSize[LST_INTEGER]*2*mGlobalScope->mStateCount + LSCRIPTDataSize

#261 [LST_INTEGER]);

#262 }

#263 integer2bytestream(code->mStates->mCodeChunk, nooffset, mGlobalScope->mStateCount);

#264 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, code->mStates, NULL, stacksize, entry,

#265 entrycount, NULL);

#266

#267 // now, put it all together and spit it out

#268 // we need

#269 FILE* bcfp = LLFile::fopen(mBytecodeDest, "wb"); /*Flawfinder: ignore*/

#270

#271 code->build(fp, bcfp);

#272 fclose(bcfp);

#273

#274 delete code;

#275 }

#276 break;

输出 CIL 的汇编代码。

#277 case LSCP_EMIT_CIL_ASSEMBLY:

#278

#279 // Output dependencies.

#280 fprintf(fp, ".assembly extern mscorlib {.ver 1:0:5000:0}/n");

#281 fprintf(fp, ".assembly extern LScriptLibrary {.ver 0:0:0:0}/n");

#282

#283 // Output assembly name.

#284 fprintf(fp, ".assembly 'lsl' {.ver 0:0:0:0}/n");

#285

#286 // Output class header.

#287 fprintf(fp, ".class public auto ansi beforefieldinit LSL extends [mscorlib]System.Object/n");

#288 fprintf(fp, "{/n");

#289

#290 // Output globals as members.

#291 if(NULL != mGlobals)

#292 {

#293 print_cil_globals(fp, mGlobals);

#294 }

#295

#296 // Output "runtime". Only needed to allow stand alone execution. Not needed when compiling to DLL and using embedded runtime.

#297 fprintf(fp, ".method public static hidebysig default void Main () cil managed/n");

#298 fprintf(fp, "{/n");

#299 fprintf(fp, ".entrypoint/n");

#300 fprintf(fp, ".maxstack 2/n");

#301 fprintf(fp, ".locals init (class LSL V_0)/n");

#302 fprintf(fp, "newobj instance void class LSL::.ctor()/n");

#303 fprintf(fp, "stloc.0/n");

#304 fprintf(fp, "ldloc.0/n");

#305 fprintf(fp, "callvirt instance void class LSL::defaultstate_entry()/n");

#306 fprintf(fp, "ret/n");

#307 fprintf(fp, "}/n");

#308

#309 // Output ctor header.

#310 fprintf(fp, ".method public hidebysig specialname rtspecialname instance default void .ctor () cil managed/n");

#311 fprintf(fp, "{/n");

#312 fprintf(fp, ".maxstack 500/n");

#313

#314 // Initialise globals as members in ctor.

#315 if (mGlobals)

#316 {

#317 fdotabs(fp, tabs, tabsize);

#318 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#319 NULL);

#320 fprintf(fp, "/n");

#321 }

#322

#323 // Output ctor footer.

#324 fprintf(fp, "ldarg.0/n");

#325 fprintf(fp, "call instance void valuetype [mscorlib]System.Object::.ctor()/n");

#326 fprintf(fp, "ret/n");

#327 fprintf(fp, "}/n");

#328

#329 // Output functions as methods.

#330 if (mGlobalFunctions)

#331 {

#332 fdotabs(fp, tabs, tabsize);

#333 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#334 entrycount, NULL);

#335 fprintf(fp, "/n");

#336 }

#337

#338 // Output states as name mangled methods.

#339 fdotabs(fp, tabs, tabsize);

#340 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#341 fprintf(fp, "/n");

#342

#343 // Output class footer.

#344 fprintf(fp, "}/n");

#345

#346 break;

下面进行缺省的处理。

#347 default:

#348 if (mGlobals)

#349 mGlobals->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount,

#350 NULL);

#351 if (mGlobalFunctions)

#352 mGlobalFunctions->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry,

#353 entrycount, NULL);

#354 mStates->recurse(fp, tabs, tabsize, pass, ptype, prunearg, scope, type, basetype, count, chunk, heap, stacksize, entry, entrycount, NULL);

#355 break;

#356 }

#357 }

#358

通过上面的代码，看到对脚本代码完整的分析过程，其实它是依照下面的状态来进行不同的阶段处理的，如下：

#001 typedef enum e_lscript_compile_pass

#002 {

非法编译状态。

#003 LSCP_INVALID,

输出合适的说明文字

#004 LSCP_PRETTY_PRINT,

进行代码化减和优化。

#005 LSCP_PRUNE,

对脚本代码进行全局的作用域检查。

#006 LSCP_SCOPE_PASS1,

对脚本代码进行跳转等作用域检查。

#007 LSCP_SCOPE_PASS2,

对脚本代码进行类型检查。

#008 LSCP_TYPE,

对脚本代码进行需要的资源分配。

#009 LSCP_RESOURCE,

对脚本代码进行汇编输出处理。

#010 LSCP_EMIT_ASSEMBLY,

对脚本代码进行字节码编译输出。

#011 LSCP_EMIT_BYTE_CODE,

对脚本代码进行事件处理计数。

#012 LSCP_DETERMINE_HANDLERS,

输出 LIB 数据。

#013 LSCP_LIST_BUILD_SIMPLE,

对于栈进行处理。

#014 LSCP_TO_STACK,

函数声明参数处理。

#015 LSCP_BUILD_FUNCTION_ARGS,

对脚本代码进行 CIL 汇编输出。

#016 LSCP_EMIT_CIL_ASSEMBLY,

脚本处理结束状态。

#017 LSCP_EOF

#018 } LSCRIPTCompilePass;

因此一个脚本代码需要经过上面 13 种的组合分析，才会真正地处理完脚本的编译，这是一个非常复杂漫长的过程。

第二人生的源码分析(112)脚本的综合分析（2）

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