From df1a10ece6a75f230d98c6fb001349eede90387a Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Tue, 14 Nov 2006 03:05:08 +0000
Subject: [PATCH] Implement removeDeadPasses().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31722 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/VMCore/PassManager.cpp | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/lib/VMCore/PassManager.cpp b/lib/VMCore/PassManager.cpp
index 2332fed5de5..0f52b2d674e 100644
--- a/lib/VMCore/PassManager.cpp
+++ b/lib/VMCore/PassManager.cpp
@@ -53,7 +53,7 @@ public:
   void removeNotPreservedAnalysis(Pass *P);
   
   /// Remove dead passes
-  void removeDeadPasses() { /* TODO : Implement */ }
+  void removeDeadPasses(Pass *P);
 
   /// Add pass P into the PassVector. Update RequiredAnalysis and
   /// AvailableAnalysis appropriately if ProcessAnalysis is true.
@@ -292,6 +292,25 @@ void CommonPassManagerImpl::removeNotPreservedAnalysis(Pass *P) {
   }
 }
 
+/// Remove analysis passes that are not used any longer
+void CommonPassManagerImpl::removeDeadPasses(Pass *P) {
+
+  for (std::map<Pass *, Pass *>::iterator I = LastUser.begin(),
+         E = LastUser.end(); I !=E; ++I) {
+    if (I->second == P) {
+      Pass *deadPass = I->first;
+      deadPass->releaseMemory();
+
+      std::map<AnalysisID, Pass*>::iterator Pos = 
+        AvailableAnalysis.find(deadPass->getPassInfo());
+      
+      assert (Pos != AvailableAnalysis.end() &&
+              "Pass is not available");
+      AvailableAnalysis.erase(Pos);
+    }
+  }
+}
+
 /// Add pass P into the PassVector. Update RequiredAnalysis and
 /// AvailableAnalysis appropriately if ProcessAnalysis is true.
 void CommonPassManagerImpl::addPassToManager (Pass *P, 
@@ -349,7 +368,7 @@ BasicBlockPassManager_New::runOnFunction(Function &F) {
       BasicBlockPass *BP = dynamic_cast<BasicBlockPass*>(P);
       Changed |= BP->runOnBasicBlock(*I);
       removeNotPreservedAnalysis(P);
-      removeDeadPasses();
+      removeDeadPasses(P);
     }
   return Changed;
 }
@@ -439,7 +458,7 @@ FunctionPassManagerImpl_New::runOnModule(Module &M) {
       FunctionPass *FP = dynamic_cast<FunctionPass*>(P);
       Changed |= FP->runOnFunction(*I);
       removeNotPreservedAnalysis(P);
-      removeDeadPasses();
+      removeDeadPasses(P);
     }
   return Changed;
 }
@@ -514,7 +533,7 @@ ModulePassManager_New::runOnModule(Module &M) {
     ModulePass *MP = dynamic_cast<ModulePass*>(P);
     Changed |= MP->runOnModule(M);
     removeNotPreservedAnalysis(P);
-    removeDeadPasses();
+    removeDeadPasses(P);
   }
   return Changed;
 }