fix PR11464 by preventing the linker from mapping two different struct types from the source module onto the same opaque destination type. An opaque type can only be resolved to one thing or another after all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146929 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Linker/LinkModules.cpp

@@ -38,9 +38,14 @@ class TypeMapTy : public ValueMapTypeRemapper {
   /// case we need to roll back.
   SmallVector<Type*, 16> SpeculativeTypes;
   
-  /// DefinitionsToResolve - This is a list of non-opaque structs in the source
-  /// module that are mapped to an opaque struct in the destination module.
-  SmallVector<StructType*, 16> DefinitionsToResolve;
+  /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
+  /// source module that are mapped to an opaque struct in the destination
+  /// module.
+  SmallVector<StructType*, 16> SrcDefinitionsToResolve;
+  
+  /// DstResolvedOpaqueTypes - This is the set of opaque types in the
+  /// destination modules who are getting a body from the source module.
+  SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
 public:
   
   /// addTypeMapping - Indicate that the specified type in the destination
@@ -118,11 +123,17 @@ bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
       return true;
     }
 
-    // Mapping a non-opaque source type to an opaque dest.  Keep the dest, but
-    // fill it in later.  This doesn't need to be speculative.
+    // Mapping a non-opaque source type to an opaque dest.  If this is the first
+    // type that we're mapping onto this destination type then we succeed.  Keep
+    // the dest, but fill it in later.  This doesn't need to be speculative.  If
+    // this is the second (different) type that we're trying to map onto the
+    // same opaque type then we fail.
     if (cast<StructType>(DstTy)->isOpaque()) {
+      // We can only map one source type onto the opaque destination type.
+      if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
+        return false;
+      SrcDefinitionsToResolve.push_back(SSTy);
       Entry = DstTy;
-      DefinitionsToResolve.push_back(SSTy);
       return true;
     }
   }
@@ -174,9 +185,9 @@ void TypeMapTy::linkDefinedTypeBodies() {
   SmallString<16> TmpName;
   
   // Note that processing entries in this loop (calling 'get') can add new
-  // entries to the DefinitionsToResolve vector.
-  while (!DefinitionsToResolve.empty()) {
-    StructType *SrcSTy = DefinitionsToResolve.pop_back_val();
+  // entries to the SrcDefinitionsToResolve vector.
+  while (!SrcDefinitionsToResolve.empty()) {
+    StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
     StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
     
     // TypeMap is a many-to-one mapping, if there were multiple types that
@@ -204,6 +215,8 @@ void TypeMapTy::linkDefinedTypeBodies() {
       TmpName.clear();
     }
   }
+  
+  DstResolvedOpaqueTypes.clear();
 }
 
 
@@ -213,7 +226,7 @@ Type *TypeMapTy::get(Type *Ty) {
   Type *Result = getImpl(Ty);
   
   // If this caused a reference to any struct type, resolve it before returning.
-  if (!DefinitionsToResolve.empty())
+  if (!SrcDefinitionsToResolve.empty())
     linkDefinedTypeBodies();
   return Result;
 }
@@ -304,8 +317,10 @@ Type *TypeMapTy::getImpl(Type *Ty) {
   
   // Otherwise we create a new type and resolve its body later.  This will be
   // resolved by the top level of get().
-  DefinitionsToResolve.push_back(STy);
-  return *Entry = StructType::create(STy->getContext());
+  SrcDefinitionsToResolve.push_back(STy);
+  StructType *DTy = StructType::create(STy->getContext());
+  DstResolvedOpaqueTypes.insert(DTy);
+  return *Entry = DTy;
 }
 
 

test/Linker/multiple-merged-structs.ll

@@ -0,0 +1,19 @@
+; RUN: echo {%bug_type = type opaque \
+; RUN:     declare i32 @bug_a(%bug_type*) \
+; RUN:     declare i32 @bug_b(%bug_type*) } > %t.ll
+; RUN: llvm-link %t.ll %s
+; PR11464
+
+%bug_type = type { %bug_type* }
+%bar = type { i32 }
+
+define i32 @bug_a(%bug_type* %fp) nounwind uwtable {
+entry:
+  %d_stream = getelementptr inbounds %bug_type* %fp, i64 0, i32 0
+  ret i32 0
+}
+
+define i32 @bug_b(%bar* %a) nounwind uwtable {
+entry:
+  ret i32 0
+}