Reapply r110396, with fixes to appease the Linux buildbot gods.

[oota-llvm.git] / lib / Transforms / IPO / ConstantMerge.cpp

diff --git a/lib/Transforms/IPO/ConstantMerge.cpp b/lib/Transforms/IPO/ConstantMerge.cpp
index 7c71065674ec798a538f6f75de871a0d91cff503..75282fae18bc531bc5a981faccdce66a6ddc311e 100644 (file)
--- a/lib/Transforms/IPO/ConstantMerge.cpp
+++ b/lib/Transforms/IPO/ConstantMerge.cpp
@@ -19,38 +19,40 @@
 
 #define DEBUG_TYPE "constmerge"
 #include "llvm/Transforms/IPO.h"
+#include "llvm/DerivedTypes.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/Support/Compiler.h"
 using namespace llvm;
 
 STATISTIC(NumMerged, "Number of global constants merged");
 
 namespace {
-  struct VISIBILITY_HIDDEN ConstantMerge : public ModulePass {
+  struct ConstantMerge : public ModulePass {
     static char ID; // Pass identification, replacement for typeid
-    ConstantMerge() : ModulePass((intptr_t)&ID) {}
+    ConstantMerge() : ModulePass(ID) {}
 
     // run - For this pass, process all of the globals in the module,
     // eliminating duplicate constants.
     //
     bool runOnModule(Module &M);
   };
-
-  char ConstantMerge::ID = 0;
-  RegisterPass<ConstantMerge>X("constmerge","Merge Duplicate Global Constants");
 }
 
+char ConstantMerge::ID = 0;
+INITIALIZE_PASS(ConstantMerge, "constmerge",
+                "Merge Duplicate Global Constants", false, false);
+
 ModulePass *llvm::createConstantMergePass() { return new ConstantMerge(); }
 
 bool ConstantMerge::runOnModule(Module &M) {
   // Map unique constant/section pairs to globals.  We don't want to merge
   // globals in different sections.
-  std::map<std::pair<Constant*, std::string>, GlobalVariable*> CMap;
+  DenseMap<Constant*, GlobalVariable*> CMap;
 
   // Replacements - This vector contains a list of replacements to perform.
-  std::vector<std::pair<GlobalVariable*, GlobalVariable*> > Replacements;
+  SmallVector<std::pair<GlobalVariable*, GlobalVariable*>, 32> Replacements;
 
   bool MadeChange = false;
 
@@ -70,28 +72,26 @@ bool ConstantMerge::runOnModule(Module &M) {
       
       // If this GV is dead, remove it.
       GV->removeDeadConstantUsers();
-      if (GV->use_empty() && GV->hasInternalLinkage()) {
+      if (GV->use_empty() && GV->hasLocalLinkage()) {
         GV->eraseFromParent();
         continue;
       }
       
-      // Only process constants with initializers.
-      if (GV->isConstant() && GV->hasInitializer()) {
-        Constant *Init = GV->getInitializer();
-
-        // Check to see if the initializer is already known.
-        GlobalVariable *&Slot = CMap[std::make_pair(Init, GV->getSection())];
-
-        if (Slot == 0) {    // Nope, add it to the map.
-          Slot = GV;
-        } else if (GV->hasInternalLinkage()) {    // Yup, this is a duplicate!
-          // Make all uses of the duplicate constant use the canonical version.
-          Replacements.push_back(std::make_pair(GV, Slot));
-        } else if (GV->hasInternalLinkage()) {
-          // Make all uses of the duplicate constant use the canonical version.
-          Replacements.push_back(std::make_pair(Slot, GV));
-          Slot = GV;
-        }
+      // Only process constants with initializers in the default addres space.
+      if (!GV->isConstant() ||!GV->hasDefinitiveInitializer() ||
+          GV->getType()->getAddressSpace() != 0 || !GV->getSection().empty())
+        continue;
+      
+      Constant *Init = GV->getInitializer();
+
+      // Check to see if the initializer is already known.
+      GlobalVariable *&Slot = CMap[Init];
+
+      if (Slot == 0) {    // Nope, add it to the map.
+        Slot = GV;
+      } else if (GV->hasLocalLinkage()) {    // Yup, this is a duplicate!
+        // Make all uses of the duplicate constant use the canonical version.
+        Replacements.push_back(std::make_pair(GV, Slot));
       }
     }
 
@@ -103,11 +103,11 @@ bool ConstantMerge::runOnModule(Module &M) {
     // now.  This avoid invalidating the pointers in CMap, which are unneeded
     // now.
     for (unsigned i = 0, e = Replacements.size(); i != e; ++i) {
-      // Eliminate any uses of the dead global...
+      // Eliminate any uses of the dead global.
       Replacements[i].first->replaceAllUsesWith(Replacements[i].second);
 
-      // Delete the global value from the module...
-      M.getGlobalList().erase(Replacements[i].first);
+      // Delete the global value from the module.
+      Replacements[i].first->eraseFromParent();
     }
 
     NumMerged += Replacements.size();