Postpone the deletion of the old name in StructType::setName to allow using a slice of the old name.

Fixes PR13522. Add a rudimentary unit test to exercise the behavior.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161296 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 50 insertions, 10 deletions

diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index c6f35580e1..5e9a00fc08 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -464,19 +464,26 @@ void StructType::setBody(ArrayRef<Type*> Elements, bool isPacked) {
 void StructType::setName(StringRef Name) {
   if (Name == getName()) return;
 
-  // If this struct already had a name, remove its symbol table entry.
-  if (SymbolTableEntry) {
-    getContext().pImpl->NamedStructTypes.erase(getName());
-    SymbolTableEntry = 0;
-  }
-  
+  StringMap<StructType *> &SymbolTable = getContext().pImpl->NamedStructTypes;
+  typedef StringMap<StructType *>::MapEntryTy EntryTy;
+
+  // If this struct already had a name, remove its symbol table entry. Don't
+  // delete the data yet because it may be part of the new name.
+  if (SymbolTableEntry)
+    SymbolTable.remove((EntryTy *)SymbolTableEntry);
+
   // If this is just removing the name, we're done.
-  if (Name.empty())
+  if (Name.empty()) {
+    if (SymbolTableEntry) {
+      // Delete the old string data.
+      ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
+      SymbolTableEntry = 0;
+    }
     return;
+  }
   
   // Look up the entry for the name.
-  StringMapEntry<StructType*> *Entry =
-    &getContext().pImpl->NamedStructTypes.GetOrCreateValue(Name);
+  EntryTy *Entry = &getContext().pImpl->NamedStructTypes.GetOrCreateValue(Name);
   
   // While we have a name collision, try a random rename.
   if (Entry->getValue()) {
@@ -497,7 +504,10 @@ void StructType::setName(StringRef Name) {
 
   // Okay, we found an entry that isn't used.  It's us!
   Entry->setValue(this);
-    
+
+  // Delete the old string data.
+  if (SymbolTableEntry)
+    ((EntryTy *)SymbolTableEntry)->Destroy(SymbolTable.getAllocator());
   SymbolTableEntry = Entry;
 }
 
diff --git a/unittests/VMCore/TypesTest.cpp b/unittests/VMCore/TypesTest.cpp
new file mode 100644
index 0000000000..0416643221
--- /dev/null
+++ b/unittests/VMCore/TypesTest.cpp
@@ -0,0 +1,30 @@
+//===- llvm/unittest/VMCore/TypesTest.cpp - Type unit tests ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DerivedTypes.h"
+#include "llvm/LLVMContext.h"
+#include "gtest/gtest.h"
+using namespace llvm;
+
+namespace {
+
+TEST(TypesTest, StructType) {
+  LLVMContext C;
+
+  // PR13522
+  StructType *Struct = StructType::create(C, "FooBar");
+  EXPECT_EQ("FooBar", Struct->getName());
+  Struct->setName(Struct->getName().substr(0, 3));
+  EXPECT_EQ("Foo", Struct->getName());
+  Struct->setName("");
+  EXPECT_TRUE(Struct->getName().empty());
+  EXPECT_FALSE(Struct->hasName());
+}
+
+}  // end anonymous namespace