[llvm] r218302 - Do not destroy external linkage when deleting function body

[Petar Jovanovic]

Author: petarj
Date: Tue Sep 23 07:54:19 2014
New Revision: 218302

URL: http://llvm.org/viewvc/llvm-project?rev=218302&view=rev
Log:
Do not destroy external linkage when deleting function body

The function deleteBody() converts the linkage to external and thus destroys
original linkage type value. Lack of correct linkage type causes wrong
relocations to be emitted later.
Calling dropAllReferences() instead of deleteBody() will fix the issue.

Differential Revision: http://reviews.llvm.org/D5415

Modified:
    llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
    llvm/trunk/unittests/Bitcode/BitReaderTest.cpp

Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=218302&r1=218301&r2=218302&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Tue Sep 23 07:54:19 2014
@@ -3347,7 +3347,7 @@ void BitcodeReader::Dematerialize(Global
   assert(DeferredFunctionInfo.count(F) && "No info to read function later?");
 
   // Just forget the function body, we can remat it later.
-  F->deleteBody();
+  F->dropAllReferences();
 }
 
 std::error_code BitcodeReader::MaterializeModule(Module *M) {

Modified: llvm/trunk/unittests/Bitcode/BitReaderTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Bitcode/BitReaderTest.cpp?rev=218302&r1=218301&r2=218302&view=diff
==============================================================================
--- llvm/trunk/unittests/Bitcode/BitReaderTest.cpp (original)
+++ llvm/trunk/unittests/Bitcode/BitReaderTest.cpp Tue Sep 23 07:54:19 2014
@@ -58,6 +58,30 @@ static std::unique_ptr<Module> getLazyMo
   return std::unique_ptr<Module>(ModuleOrErr.get());
 }
 
+TEST(BitReaderTest, DematerializeFunctionPreservesLinkageType) {
+  SmallString<1024> Mem;
+
+  LLVMContext Context;
+  std::unique_ptr<Module> M = getLazyModuleFromAssembly(
+      Context, Mem, "define internal i32 @func() {\n"
+                      "ret i32 0\n"
+                    "}\n");
+
+  EXPECT_FALSE(verifyModule(*M, &dbgs()));
+
+  M->getFunction("func")->Materialize();
+  EXPECT_FALSE(M->getFunction("func")->empty());
+  EXPECT_TRUE(M->getFunction("func")->getLinkage() ==
+              GlobalValue::InternalLinkage);
+
+  // Check that the linkage type is preserved after dematerialization.
+  M->getFunction("func")->Dematerialize();
+  EXPECT_TRUE(M->getFunction("func")->empty());
+  EXPECT_TRUE(M->getFunction("func")->getLinkage() ==
+              GlobalValue::InternalLinkage);
+  EXPECT_FALSE(verifyModule(*M, &dbgs()));
+}
+
 TEST(BitReaderTest, MaterializeFunctionsForBlockAddr) { // PR11677
   SmallString<1024> Mem;