From: Petar Jovanovic <petar.jovanovic@imgtec.com>
Date: Tue, 23 Sep 2014 12:54:19 +0000 (+0000)
Subject: Do not destroy external linkage when deleting function body
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=fd42335e831d256f34b4bd995fe8dc1e8d8d2f2c

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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218302 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 80afb56e746..f113c2c71d1 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3347,7 +3347,7 @@ void BitcodeReader::Dematerialize(GlobalValue *GV) {
   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) {
diff --git a/unittests/Bitcode/BitReaderTest.cpp b/unittests/Bitcode/BitReaderTest.cpp
index a27332b5b35..04c795038fc 100644
--- a/unittests/Bitcode/BitReaderTest.cpp
+++ b/unittests/Bitcode/BitReaderTest.cpp
@@ -58,6 +58,30 @@ static std::unique_ptr<Module> getLazyModuleFromAssembly(LLVMContext &Context,
   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;