WHIRL Generator (WGEN in Open64) 笔记

WHIRL Gen 核心逻辑（Spin 2 whirl）

（就是获取spin的每个node）

gs_t 就是 spin的单个AST node

使用gs_operand(list,0)获取当前node的is_t，

使用 list = gs_operand(list,1)获取下一个node

获取node之后使用 WGEN_Expand_Top_Level_Decl (gs_t decl) 来展开莫个gs_t()

之后就是各种调用WGEN_Expand_Decl ，包括递归调用

---

中间可能出现:

———   Function   ——— 

WGEN_Expand_Function_Body

WGEN_Start_Function

WGEN_Handle_Named_Return_Value

Mark_Scopes_And_Labels

WGEN_Expand_Stmt

WGEN_Finish_Function

Pop_Current_Function_Decl

Push_Current_Function_Decl

——  Whirl  ——— 

WGEN_Whirlify_Decl

WGEN_Initialize_Decl

———  Thunk  ——— 

WGEN_Adjust_Thunk

WGEN_Generate_Thunk  — For adjusting return or this pointer.

———  Symtab ——— 

WN_st_idx()

ST_st_idx(const char *)  string -> str_id / saving  function name to symtab 

———  WN ——— 

WN_Set_Call_Default_Flags

WN_Set_Call_Replace_By_Jump

WN_Ldid

WN_CreateParm(Mtype_comparison (arg_mtype), arg_wn,

                           arg_ty, WN_PARM_BY_VALUE);

WN_kid = ***   Set kid of WN

WN_Create (OPR_CALL, ret_mtype, MTYPE_V, nargs)

WN_st

WN_CreateReturn

WN_Stid

——   Statement. ——— 

WGEN_Stmt_Append(wn, getsrcpos())

Mark_Scopes_And_Labels()

WGEN_Expand_Stmt

WGEN_GetLABEL

WGEN_Assembly_Alias

---

BT实测结果

frame #0: 0x0000000100070282 wgen`::WGEN_Expand_Decl(decl=0x0000000101800580, can_skip=YES) at wgen_decl.cxx:709

 frame #1: 0x000000010007b5dd wgen`::WGEN_Expand_Top_Level_Decl(top_level_decl=0x0000000101800580) at wgen_decl.cxx:5208

    frame #2: 0x0000000100002555 wgen`main(argc=3, argv=0x00007fff5fbffa88, envp=0x00007fff5fbffaa8) at main.c:362