From 5858e1e3f3358d53a7aeff1a7a19a862bb814df3 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 21 Oct 2003 23:17:56 +0000
Subject: [PATCH] Fix bug: FunctionResolve/2003-10-21-GlobalTypeDifference.ll

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9359 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/FunctionResolution.cpp | 74 ++++++-----------------
 1 file changed, 19 insertions(+), 55 deletions(-)

diff --git a/lib/Transforms/IPO/FunctionResolution.cpp b/lib/Transforms/IPO/FunctionResolution.cpp
index 93e1745b6d4..ecabc692b4f 100644
--- a/lib/Transforms/IPO/FunctionResolution.cpp
+++ b/lib/Transforms/IPO/FunctionResolution.cpp
@@ -109,29 +109,15 @@ static bool ResolveGlobalVariables(Module &M,
                                    std::vector<GlobalValue*> &Globals,
                                    GlobalVariable *Concrete) {
   bool Changed = false;
-  assert(isa<ArrayType>(Concrete->getType()->getElementType()) &&
-         "Concrete version should be an array type!");
-
-  // Get the type of the things that may be resolved to us...
-  const ArrayType *CATy =cast<ArrayType>(Concrete->getType()->getElementType());
-  const Type *AETy = CATy->getElementType();
-
   Constant *CCPR = ConstantPointerRef::get(Concrete);
 
   for (unsigned i = 0; i != Globals.size(); ++i)
     if (Globals[i] != Concrete) {
-      GlobalVariable *Old = cast<GlobalVariable>(Globals[i]);
-      const ArrayType *OATy = cast<ArrayType>(Old->getType()->getElementType());
-      if (OATy->getElementType() != AETy || OATy->getNumElements() != 0) {
-        std::cerr << "WARNING: Two global variables exist with the same name "
-                  << "that cannot be resolved!\n";
-        return false;
-      }
-
-      Old->replaceAllUsesWith(ConstantExpr::getCast(CCPR, Old->getType()));
+      Constant *Cast = ConstantExpr::getCast(CCPR, Globals[i]->getType());
+      Globals[i]->replaceAllUsesWith(Cast);
 
       // Since there are no uses of Old anymore, remove it from the module.
-      M.getGlobalList().erase(Old);
+      M.getGlobalList().erase(cast<GlobalVariable>(Globals[i]));
 
       ++NumGlobals;
       Changed = true;
@@ -176,32 +162,15 @@ static bool ProcessGlobalsWithSameName(Module &M,
         Concrete = F;
       }
     } else {
-      // For global variables, we have to merge C definitions int A[][4] with
-      // int[6][4].  A[][4] is represented as A[0][4] by the CFE.
       GlobalVariable *GV = cast<GlobalVariable>(Globals[i]);
-      if (!isa<ArrayType>(GV->getType()->getElementType())) {
-        Concrete = 0;
-        break;  // Non array's cannot be compatible with other types.
-      } else if (Concrete == 0) {
-        Concrete = GV;
-      } else {
-        // Must have different types... allow merging A[0][4] w/ A[6][4] if
-        // A[0][4] is external.
-        const ArrayType *NAT = cast<ArrayType>(GV->getType()->getElementType());
-        const ArrayType *CAT =
-          cast<ArrayType>(Concrete->getType()->getElementType());
-
-        if (NAT->getElementType() != CAT->getElementType()) {
-          Concrete = 0;  // Non-compatible types
-          break;
-        } else if (NAT->getNumElements() == 0 && GV->isExternal()) {
-          // Concrete remains the same
-        } else if (CAT->getNumElements() == 0 && Concrete->isExternal()) {
-          Concrete = GV;   // Concrete becomes GV
-        } else {
-          Concrete = 0;    // Cannot merge these types...
-          break;
+      if (!GV->isExternal()) {
+        if (Concrete) {
+          std::cerr << "WARNING: Two global variables with external linkage"
+                    << " exist with the same name: '" << GV->getName()
+                    << "'!\n";
+          return false;
         }
+        Concrete = GV;
       }
     }
     ++i;
@@ -225,21 +194,15 @@ static bool ProcessGlobalsWithSameName(Module &M,
       return false;  // Nothing to do?  Must have multiple internal definitions.
 
 
-    // We should find exactly one concrete function definition, which is
-    // probably the implementation.  Change all of the function definitions and
-    // uses to use it instead.
-    //
-    if (!Concrete) {
-      std::cerr << "WARNING: Found global types that are not compatible:\n";
-      for (unsigned i = 0; i < Globals.size(); ++i) {
-        std::cerr << "\t" << Globals[i]->getType()->getDescription() << " %"
-                  << Globals[i]->getName() << "\n";
-      }
-      std::cerr << "  No linkage of globals named '" << Globals[0]->getName()
-                << "' performed!\n";
-      return false;
+    std::cerr << "WARNING: Found global types that are not compatible:\n";
+    for (unsigned i = 0; i < Globals.size(); ++i) {
+      std::cerr << "\t" << *Globals[i]->getType() << " %"
+                << Globals[i]->getName() << "\n";
     }
 
+    if (!Concrete)
+      Concrete = Globals[0];
+
     if (isFunction)
       return ResolveFunctions(M, Globals, cast<Function>(Concrete));
     else
@@ -266,7 +229,8 @@ bool FunctionResolvingPass::run(Module &M) {
         GlobalValue *GV = cast<GlobalValue>(PI->second);
         assert(PI->first == GV->getName() &&
                "Global name and symbol table do not agree!");
-        Globals[PI->first].push_back(GV);
+        if (!GV->hasInternalLinkage())
+          Globals[PI->first].push_back(GV);
       }
     }
 
-- 
2.34.1