Add a comment about ATTRIBUTE_UNUSED to avoid further confusion over when to

[oota-llvm.git] / include / llvm / PassSupport.h

diff --git a/include/llvm/PassSupport.h b/include/llvm/PassSupport.h
index ecccf791fe0cdaada1d61fe38294fb6f52b29c9b..d1b4f268c4b82656eabd294a1976c4b5cfea8377 100644 (file)
--- a/include/llvm/PassSupport.h
+++ b/include/llvm/PassSupport.h
@@ -24,7 +24,7 @@
 #include "Pass.h"
 #include "llvm/PassRegistry.h"
 #include "llvm/InitializePasses.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/System/Atomic.h"
 #include <vector>
 
 namespace llvm {
@@ -129,6 +129,22 @@ private:
   PassInfo(const PassInfo &);       // do not implement
 };
 
+#define CALL_ONCE_INITIALIZATION(function) \
+  static volatile sys::cas_flag initialized = 0; \
+  sys::cas_flag old_val = sys::CompareAndSwap(&initialized, 1, 0); \
+  if (old_val == 0) { \
+    function(Registry); \
+    sys::MemoryFence(); \
+    initialized = 2; \
+  } else { \
+    sys::cas_flag tmp = initialized; \
+    sys::MemoryFence(); \
+    while (tmp != 2) { \
+      tmp = initialized; \
+      sys::MemoryFence(); \
+    } \
+  }
+
 #define INITIALIZE_PASS(passName, arg, name, cfg, analysis) \
   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
     PassInfo *PI = new PassInfo(name, arg, & passName ::ID, \
@@ -137,10 +153,8 @@ private:
     return PI; \
   } \
   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
-    ATTRIBUTE_USED \
-    static void* initialized = initialize##passName##PassOnce(Registry); \
-  } \
-  static RegisterPass<passName> passName ## _info(arg, name, cfg, analysis);
+    CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
+  }
 
 #define INITIALIZE_PASS_BEGIN(passName, arg, name, cfg, analysis) \
   static void* initialize##passName##PassOnce(PassRegistry &Registry) {
@@ -157,10 +171,8 @@ private:
     return PI; \
   } \
   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
-    ATTRIBUTE_USED \
-    static void* initialized = initialize##passName##PassOnce(Registry); \
-  } \
-  static RegisterPass<passName> passName ## _info(arg, name, cfg, analysis);
+    CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
+  }
 
 template<typename PassName>
 Pass *callDefaultCtor() { return new PassName(); }
@@ -236,21 +248,21 @@ struct RegisterAnalysisGroup : public RegisterAGBase {
   }
 };
 
-#define INITIALIZE_ANALYSIS_GROUP(agName, name) \
+#define INITIALIZE_ANALYSIS_GROUP(agName, name, defaultPass) \
   static void* initialize##agName##AnalysisGroupOnce(PassRegistry &Registry) { \
+    initialize##defaultPass##Pass(Registry); \
     PassInfo *AI = new PassInfo(name, & agName :: ID); \
     Registry.registerAnalysisGroup(& agName ::ID, 0, *AI, false); \
     return AI; \
   } \
   void llvm::initialize##agName##AnalysisGroup(PassRegistry &Registry) { \
-    ATTRIBUTE_USED static void* initialized = \
-      initialize##agName##AnalysisGroupOnce(Registry); \
-  } \
-  static RegisterAnalysisGroup<agName> agName##_info (name);
+    CALL_ONCE_INITIALIZATION(initialize##agName##AnalysisGroupOnce) \
+  }
+
 
 #define INITIALIZE_AG_PASS(passName, agName, arg, name, cfg, analysis, def) \
   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
-    initialize##agName##AnalysisGroup(Registry); \
+    if (!def) initialize##agName##AnalysisGroup(Registry); \
     PassInfo *PI = new PassInfo(name, arg, & passName ::ID, \
       PassInfo::NormalCtor_t(callDefaultCtor< passName >), cfg, analysis); \
     Registry.registerPass(*PI); \
@@ -260,15 +272,13 @@ struct RegisterAnalysisGroup : public RegisterAGBase {
     return AI; \
   } \
   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
-    ATTRIBUTE_USED \
-    static void* initialized = initialize##passName##PassOnce(Registry); \
-  } \
-  static RegisterPass<passName> passName ## _info(arg, name, cfg, analysis); \
-  static RegisterAnalysisGroup<agName, def> passName ## _ag(passName ## _info);
+    CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
+  }
+
 
 #define INITIALIZE_AG_PASS_BEGIN(passName, agName, arg, n, cfg, analysis, def) \
   static void* initialize##passName##PassOnce(PassRegistry &Registry) { \
-    initialize##agName##AnalysisGroup(Registry);
+    if (!def) initialize##agName##AnalysisGroup(Registry);
 
 #define INITIALIZE_AG_PASS_END(passName, agName, arg, n, cfg, analysis, def) \
     PassInfo *PI = new PassInfo(n, arg, & passName ::ID, \
@@ -280,11 +290,8 @@ struct RegisterAnalysisGroup : public RegisterAGBase {
     return AI; \
   } \
   void llvm::initialize##passName##Pass(PassRegistry &Registry) { \
-    ATTRIBUTE_USED \
-    static void* initialized = initialize##passName##PassOnce(Registry); \
-  } \
-  static RegisterPass<passName> passName ## _info(arg, n, cfg, analysis); \
-  static RegisterAnalysisGroup<agName, def> passName ## _ag(passName ## _info);
+    CALL_ONCE_INITIALIZATION(initialize##passName##PassOnce) \
+  }
 
 //===---------------------------------------------------------------------------
 /// PassRegistrationListener class - This class is meant to be derived from by