X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FExtractGV.cpp;h=40ec9fa8c1dea825b5b4b8a15e0dd2bdc85f3701;hb=d94715e273d879eab53684835375ddbed7eb1eb3;hp=9d432de9fa7b7fd7704ba3291c735e6e8ff85783;hpb=edf017487ffdd52cd42f3129c0e6b78fffb31e89;p=oota-llvm.git

diff --git a/lib/Transforms/IPO/ExtractGV.cpp b/lib/Transforms/IPO/ExtractGV.cpp
index 9d432de9fa7..40ec9fa8c1d 100644
--- a/lib/Transforms/IPO/ExtractGV.cpp
+++ b/lib/Transforms/IPO/ExtractGV.cpp
@@ -11,16 +11,47 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Instructions.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Constants.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/ADT/SetVector.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
 #include <algorithm>
 using namespace llvm;
 
+/// Make sure GV is visible from both modules. Delete is true if it is
+/// being deleted from this module.
+/// This also makes sure GV cannot be dropped so that references from
+/// the split module remain valid.
+static void makeVisible(GlobalValue &GV, bool Delete) {
+  bool Local = GV.hasLocalLinkage();
+  if (Local || Delete) {
+    GV.setLinkage(GlobalValue::ExternalLinkage);
+    if (Local)
+      GV.setVisibility(GlobalValue::HiddenVisibility);
+    return;
+  }
+
+  if (!GV.hasLinkOnceLinkage()) {
+    assert(!GV.isDiscardableIfUnused());
+    return;
+  }
+
+  // Map linkonce* to weak* so that llvm doesn't drop this GV.
+  switch(GV.getLinkage()) {
+  default:
+    llvm_unreachable("Unexpected linkage");
+  case GlobalValue::LinkOnceAnyLinkage:
+    GV.setLinkage(GlobalValue::WeakAnyLinkage);
+    return;
+  case GlobalValue::LinkOnceODRLinkage:
+    GV.setLinkage(GlobalValue::WeakODRLinkage);
+    return;
+  }
+}
+
 namespace {
   /// @brief A pass to extract specific functions and their dependencies.
   class GVExtractorPass : public ModulePass {
@@ -36,7 +67,7 @@ namespace {
     explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true)
       : ModulePass(ID), Named(GVs.begin(), GVs.end()), deleteStuff(deleteS) {}
 
-    bool runOnModule(Module &M) {
+    bool runOnModule(Module &M) override {
       // Visit the global inline asm.
       if (!deleteStuff)
         M.setModuleInlineAsm("");
@@ -51,22 +82,65 @@ namespace {
       // Visit the GlobalVariables.
       for (Module::global_iterator I = M.global_begin(), E = M.global_end();
            I != E; ++I) {
-        if (I->hasLocalLinkage())
-          I->setVisibility(GlobalValue::HiddenVisibility);
-        I->setLinkage(GlobalValue::ExternalLinkage);
-        if (deleteStuff == (bool)Named.count(I) && !I->isDeclaration())
-          I->setInitializer(0);
+        bool Delete =
+          deleteStuff == (bool)Named.count(I) && !I->isDeclaration();
+        if (!Delete) {
+          if (I->hasAvailableExternallyLinkage())
+            continue;
+          if (I->getName() == "llvm.global_ctors")
+            continue;
+        }
+
+	makeVisible(*I, Delete);
+
+        if (Delete)
+          I->setInitializer(nullptr);
       }
 
       // Visit the Functions.
       for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
-        if (I->hasLocalLinkage())
-          I->setVisibility(GlobalValue::HiddenVisibility);
-        I->setLinkage(GlobalValue::ExternalLinkage);
-        if (deleteStuff == (bool)Named.count(I) && !I->isDeclaration())
+        bool Delete =
+          deleteStuff == (bool)Named.count(I) && !I->isDeclaration();
+        if (!Delete) {
+          if (I->hasAvailableExternallyLinkage())
+            continue;
+        }
+
+	makeVisible(*I, Delete);
+
+        if (Delete)
           I->deleteBody();
       }
 
+      // Visit the Aliases.
+      for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
+           I != E;) {
+        Module::alias_iterator CurI = I;
+        ++I;
+
+	bool Delete = deleteStuff == (bool)Named.count(CurI);
+	makeVisible(*CurI, Delete);
+
+        if (Delete) {
+          Type *Ty =  CurI->getType()->getElementType();
+
+          CurI->removeFromParent();
+          llvm::Value *Declaration;
+          if (FunctionType *FTy = dyn_cast<FunctionType>(Ty)) {
+            Declaration = Function::Create(FTy, GlobalValue::ExternalLinkage,
+                                           CurI->getName(), &M);
+
+          } else {
+            Declaration =
+              new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage,
+                                 nullptr, CurI->getName());
+
+          }
+          CurI->replaceAllUsesWith(Declaration);
+          delete CurI;
+        }
+      }
+
       return true;
     }
   };