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      1 //===- llvm/PassSupport.h - Pass Support code -------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines stuff that is used to define and "use" Passes.  This file
     11 // is automatically #included by Pass.h, so:
     12 //
     13 //           NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
     14 //
     15 // Instead, #include Pass.h.
     16 //
     17 // This file defines Pass registration code and classes used for it.
     18 //
     19 //===----------------------------------------------------------------------===//
     20 
     21 #ifndef LLVM_PASSSUPPORT_H
     22 #define LLVM_PASSSUPPORT_H
     23 
     24 #include "Pass.h"
     25 #include "llvm/InitializePasses.h"
     26 #include "llvm/PassRegistry.h"
     27 #include "llvm/Support/Atomic.h"
     28 #include "llvm/Support/Valgrind.h"
     29 #include <vector>
     30 
     31 namespace llvm {
     32 
     33 //===---------------------------------------------------------------------------
     34 /// PassInfo class - An instance of this class exists for every pass known by
     35 /// the system, and can be obtained from a live Pass by calling its
     36 /// getPassInfo() method.  These objects are set up by the RegisterPass<>
     37 /// template, defined below.
     38 ///
     39 class PassInfo {
     40 public:
     41   typedef Pass* (*NormalCtor_t)();
     42 
     43 private:
     44   const char      *const PassName;     // Nice name for Pass
     45   const char      *const PassArgument; // Command Line argument to run this pass
     46   const void *PassID;
     47   const bool IsCFGOnlyPass;            // Pass only looks at the CFG.
     48   const bool IsAnalysis;               // True if an analysis pass.
     49   const bool IsAnalysisGroup;          // True if an analysis group.
     50   std::vector<const PassInfo*> ItfImpl;// Interfaces implemented by this pass
     51 
     52   NormalCtor_t NormalCtor;
     53 
     54 public:
     55   /// PassInfo ctor - Do not call this directly, this should only be invoked
     56   /// through RegisterPass.
     57   PassInfo(const char *name, const char *arg, const void *pi,
     58            NormalCtor_t normal, bool isCFGOnly, bool is_analysis)
     59     : PassName(name), PassArgument(arg), PassID(pi),
     60       IsCFGOnlyPass(isCFGOnly),
     61       IsAnalysis(is_analysis), IsAnalysisGroup(false), NormalCtor(normal) { }
     62   /// PassInfo ctor - Do not call this directly, this should only be invoked
     63   /// through RegisterPass. This version is for use by analysis groups; it
     64   /// does not auto-register the pass.
     65   PassInfo(const char *name, const void *pi)
     66     : PassName(name), PassArgument(""), PassID(pi),
     67       IsCFGOnlyPass(false),
     68       IsAnalysis(false), IsAnalysisGroup(true), NormalCtor(0) { }
     69 
     70   /// getPassName - Return the friendly name for the pass, never returns null
     71   ///
     72   const char *getPassName() const { return PassName; }
     73 
     74   /// getPassArgument - Return the command line option that may be passed to
     75   /// 'opt' that will cause this pass to be run.  This will return null if there
     76   /// is no argument.
     77   ///
     78   const char *getPassArgument() const { return PassArgument; }
     79 
     80   /// getTypeInfo - Return the id object for the pass...
     81   /// TODO : Rename
     82   const void *getTypeInfo() const { return PassID; }
     83 
     84   /// Return true if this PassID implements the specified ID pointer.
     85   bool isPassID(const void *IDPtr) const {
     86     return PassID == IDPtr;
     87   }
     88 
     89   /// isAnalysisGroup - Return true if this is an analysis group, not a normal
     90   /// pass.
     91   ///
     92   bool isAnalysisGroup() const { return IsAnalysisGroup; }
     93   bool isAnalysis() const { return IsAnalysis; }
     94 
     95   /// isCFGOnlyPass - return true if this pass only looks at the CFG for the
     96   /// function.
     97   bool isCFGOnlyPass() const { return IsCFGOnlyPass; }
     98 
     99   /// getNormalCtor - Return a pointer to a function, that when called, creates
    100   /// an instance of the pass and returns it.  This pointer may be null if there
    101   /// is no default constructor for the pass.
    102   ///
    103   NormalCtor_t getNormalCtor() const {
    104     return NormalCtor;
    105   }
    106   void setNormalCtor(NormalCtor_t Ctor) {
    107     NormalCtor = Ctor;
    108   }
    109 
    110   /// createPass() - Use this method to create an instance of this pass.
    111   Pass *createPass() const;
    112 
    113   /// addInterfaceImplemented - This method is called when this pass is
    114   /// registered as a member of an analysis group with the RegisterAnalysisGroup
    115   /// template.
    116   ///
    117   void addInterfaceImplemented(const PassInfo *ItfPI) {
    118     ItfImpl.push_back(ItfPI);
    119   }
    120 
    121   /// getInterfacesImplemented - Return a list of all of the analysis group
    122   /// interfaces implemented by this pass.
    123   ///
    124   const std::vector<const PassInfo*> &getInterfacesImplemented() const {
    125     return ItfImpl;
    126   }
    127 
    128 private:
    129   void operator=(const PassInfo &) LLVM_DELETED_FUNCTION;
    130   PassInfo(const PassInfo &) LLVM_DELETED_FUNCTION;
    131 };
    132 
    133 #define CALL_ONCE_INITIALIZATION(function) \
    134   static volatile sys::cas_flag initialized = 0; \
    135   sys::cas_flag old_val = sys::CompareAndSwap(&initialized, 1, 0); \
    136   if (old_val == 0) { \
    137     function(Registry); \
    138     sys::MemoryFence(); \
    139     TsanIgnoreWritesBegin(); \
    140     TsanHappensBefore(&initialized); \
    141     initialized = 2; \
    142     TsanIgnoreWritesEnd(); \
    143   } else { \
    144     sys::cas_flag tmp = initialized; \
    145     sys::MemoryFence(); \
    146     while (tmp != 2) { \
    147       tmp = initialized; \
    148       sys::MemoryFence(); \
    149     } \
    150   } \
    151   TsanHappensAfter(&initialized);
    152 
    153 #define INITIALIZE_PASS(passName, arg, name, cfg, analysis) \
    154   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
    155     PassInfo *PI = new PassInfo(name, arg, & passName ::ID, \
    156       PassInfo::NormalCtor_t(callDefaultCtor< passName >), cfg, analysis); \
    157     Registry.registerPass(*PI, true); \
    158     return PI; \
    159   } \
    160   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
    161     CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
    162   }
    163 
    164 #define INITIALIZE_PASS_BEGIN(passName, arg, name, cfg, analysis) \
    165   static void* initialize##passName##PassOnce(PassRegistry &Registry) {
    166 
    167 #define INITIALIZE_PASS_DEPENDENCY(depName) \
    168     initialize##depName##Pass(Registry);
    169 #define INITIALIZE_AG_DEPENDENCY(depName) \
    170     initialize##depName##AnalysisGroup(Registry);
    171 
    172 #define INITIALIZE_PASS_END(passName, arg, name, cfg, analysis) \
    173     PassInfo *PI = new PassInfo(name, arg, & passName ::ID, \
    174       PassInfo::NormalCtor_t(callDefaultCtor< passName >), cfg, analysis); \
    175     Registry.registerPass(*PI, true); \
    176     return PI; \
    177   } \
    178   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
    179     CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
    180   }
    181 
    182 template<typename PassName>
    183 Pass *callDefaultCtor() { return new PassName(); }
    184 
    185 //===---------------------------------------------------------------------------
    186 /// RegisterPass<t> template - This template class is used to notify the system
    187 /// that a Pass is available for use, and registers it into the internal
    188 /// database maintained by the PassManager.  Unless this template is used, opt,
    189 /// for example will not be able to see the pass and attempts to create the pass
    190 /// will fail. This template is used in the follow manner (at global scope, in
    191 /// your .cpp file):
    192 ///
    193 /// static RegisterPass<YourPassClassName> tmp("passopt", "My Pass Name");
    194 ///
    195 /// This statement will cause your pass to be created by calling the default
    196 /// constructor exposed by the pass.  If you have a different constructor that
    197 /// must be called, create a global constructor function (which takes the
    198 /// arguments you need and returns a Pass*) and register your pass like this:
    199 ///
    200 /// static RegisterPass<PassClassName> tmp("passopt", "My Name");
    201 ///
    202 template<typename passName>
    203 struct RegisterPass : public PassInfo {
    204 
    205   // Register Pass using default constructor...
    206   RegisterPass(const char *PassArg, const char *Name, bool CFGOnly = false,
    207                bool is_analysis = false)
    208     : PassInfo(Name, PassArg, &passName::ID,
    209                PassInfo::NormalCtor_t(callDefaultCtor<passName>),
    210                CFGOnly, is_analysis) {
    211     PassRegistry::getPassRegistry()->registerPass(*this);
    212   }
    213 };
    214 
    215 
    216 /// RegisterAnalysisGroup - Register a Pass as a member of an analysis _group_.
    217 /// Analysis groups are used to define an interface (which need not derive from
    218 /// Pass) that is required by passes to do their job.  Analysis Groups differ
    219 /// from normal analyses because any available implementation of the group will
    220 /// be used if it is available.
    221 ///
    222 /// If no analysis implementing the interface is available, a default
    223 /// implementation is created and added.  A pass registers itself as the default
    224 /// implementation by specifying 'true' as the second template argument of this
    225 /// class.
    226 ///
    227 /// In addition to registering itself as an analysis group member, a pass must
    228 /// register itself normally as well.  Passes may be members of multiple groups
    229 /// and may still be "required" specifically by name.
    230 ///
    231 /// The actual interface may also be registered as well (by not specifying the
    232 /// second template argument).  The interface should be registered to associate
    233 /// a nice name with the interface.
    234 ///
    235 class RegisterAGBase : public PassInfo {
    236 public:
    237   RegisterAGBase(const char *Name,
    238                  const void *InterfaceID,
    239                  const void *PassID = 0,
    240                  bool isDefault = false);
    241 };
    242 
    243 template<typename Interface, bool Default = false>
    244 struct RegisterAnalysisGroup : public RegisterAGBase {
    245   explicit RegisterAnalysisGroup(PassInfo &RPB)
    246     : RegisterAGBase(RPB.getPassName(),
    247                      &Interface::ID, RPB.getTypeInfo(),
    248                      Default) {
    249   }
    250 
    251   explicit RegisterAnalysisGroup(const char *Name)
    252     : RegisterAGBase(Name, &Interface::ID) {
    253   }
    254 };
    255 
    256 #define INITIALIZE_ANALYSIS_GROUP(agName, name, defaultPass) \
    257   static void* initialize##agName##AnalysisGroupOnce(PassRegistry &Registry) { \
    258     initialize##defaultPass##Pass(Registry); \
    259     PassInfo *AI = new PassInfo(name, & agName :: ID); \
    260     Registry.registerAnalysisGroup(& agName ::ID, 0, *AI, false, true); \
    261     return AI; \
    262   } \
    263   void llvm::initialize##agName##AnalysisGroup(PassRegistry &Registry) { \
    264     CALL_ONCE_INITIALIZATION(initialize##agName##AnalysisGroupOnce) \
    265   }
    266 
    267 
    268 #define INITIALIZE_AG_PASS(passName, agName, arg, name, cfg, analysis, def) \
    269   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
    270     if (!def) initialize##agName##AnalysisGroup(Registry); \
    271     PassInfo *PI = new PassInfo(name, arg, & passName ::ID, \
    272       PassInfo::NormalCtor_t(callDefaultCtor< passName >), cfg, analysis); \
    273     Registry.registerPass(*PI, true); \
    274     \
    275     PassInfo *AI = new PassInfo(name, & agName :: ID); \
    276     Registry.registerAnalysisGroup(& agName ::ID, & passName ::ID, \
    277                                    *AI, def, true); \
    278     return AI; \
    279   } \
    280   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
    281     CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
    282   }
    283 
    284 
    285 #define INITIALIZE_AG_PASS_BEGIN(passName, agName, arg, n, cfg, analysis, def) \
    286   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
    287     if (!def) initialize##agName##AnalysisGroup(Registry);
    288 
    289 #define INITIALIZE_AG_PASS_END(passName, agName, arg, n, cfg, analysis, def) \
    290     PassInfo *PI = new PassInfo(n, arg, & passName ::ID, \
    291       PassInfo::NormalCtor_t(callDefaultCtor< passName >), cfg, analysis); \
    292     Registry.registerPass(*PI, true); \
    293     \
    294     PassInfo *AI = new PassInfo(n, & agName :: ID); \
    295     Registry.registerAnalysisGroup(& agName ::ID, & passName ::ID, \
    296                                    *AI, def, true); \
    297     return AI; \
    298   } \
    299   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
    300     CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
    301   }
    302 
    303 //===---------------------------------------------------------------------------
    304 /// PassRegistrationListener class - This class is meant to be derived from by
    305 /// clients that are interested in which passes get registered and unregistered
    306 /// at runtime (which can be because of the RegisterPass constructors being run
    307 /// as the program starts up, or may be because a shared object just got
    308 /// loaded).  Deriving from the PassRegistrationListener class automatically
    309 /// registers your object to receive callbacks indicating when passes are loaded
    310 /// and removed.
    311 ///
    312 struct PassRegistrationListener {
    313 
    314   /// PassRegistrationListener ctor - Add the current object to the list of
    315   /// PassRegistrationListeners...
    316   PassRegistrationListener();
    317 
    318   /// dtor - Remove object from list of listeners...
    319   ///
    320   virtual ~PassRegistrationListener();
    321 
    322   /// Callback functions - These functions are invoked whenever a pass is loaded
    323   /// or removed from the current executable.
    324   ///
    325   virtual void passRegistered(const PassInfo *) {}
    326 
    327   /// enumeratePasses - Iterate over the registered passes, calling the
    328   /// passEnumerate callback on each PassInfo object.
    329   ///
    330   void enumeratePasses();
    331 
    332   /// passEnumerate - Callback function invoked when someone calls
    333   /// enumeratePasses on this PassRegistrationListener object.
    334   ///
    335   virtual void passEnumerate(const PassInfo *) {}
    336 };
    337 
    338 
    339 } // End llvm namespace
    340 
    341 #endif
    342