[llvm] r194218 - Move copying of global initializers below the cloning of functions.

Adrian Prantl aprantl at apple.com
Fri Nov 8 16:45:00 PST 2013


Hi Bill,

I need to revert this change for now, because it breaks the following testcase:

$ cat test.ll
%foo = type { void (i32*)* }
@global_initializer = internal constant %foo { void (i32*)* @bar }

define internal void @bar(i32*) {
  ret void
}
$ llvm-link some-empty-file.ll test.ll |llvm-dis

This causes “bar” (which is only referenced by a not-yet-linked global initializer) to be removed.

cheers,
adrian

On Nov 7, 2013, at 12:14, Bill Wendling <isanbard at gmail.com> wrote:

> Author: void
> Date: Thu Nov  7 14:14:51 2013
> New Revision: 194218
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=194218&view=rev
> Log:
> Move copying of global initializers below the cloning of functions.
> 
> The BlockAddress doesn't have access to the correct basic blocks until the
> functions have been cloned. This causes the BlockAddress to point to the old
> values. Just wait until the functions have been cloned before copying the
> initializers.
> PR13163
> 
> Added:
>    llvm/trunk/unittests/Linker/
>    llvm/trunk/unittests/Linker/CMakeLists.txt
>    llvm/trunk/unittests/Linker/LinkModulesTest.cpp
>    llvm/trunk/unittests/Linker/Makefile
>      - copied, changed from r194205, llvm/trunk/unittests/Makefile
> Modified:
>    llvm/trunk/lib/Linker/LinkModules.cpp
>    llvm/trunk/unittests/Makefile
> 
> Modified: llvm/trunk/lib/Linker/LinkModules.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Linker/LinkModules.cpp?rev=194218&r1=194217&r2=194218&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Linker/LinkModules.cpp (original)
> +++ llvm/trunk/lib/Linker/LinkModules.cpp Thu Nov  7 14:14:51 2013
> @@ -1251,10 +1251,6 @@ bool ModuleLinker::run() {
>   for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
>     linkAppendingVarInit(AppendingVars[i]);
> 
> -  // Update the initializers in the DstM module now that all globals that may
> -  // be referenced are in DstM.
> -  linkGlobalInits();
> -
>   // Link in the function bodies that are defined in the source module into
>   // DstM.
>   for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
> @@ -1336,6 +1332,10 @@ bool ModuleLinker::run() {
>     }
>   } while (LinkedInAnyFunctions);
> 
> +  // Update the initializers in the DstM module now that all globals that may
> +  // be referenced are in DstM.
> +  linkGlobalInits();
> +
>   // Now that all of the types from the source are used, resolve any structs
>   // copied over to the dest that didn't exist there.
>   TypeMap.linkDefinedTypeBodies();
> 
> Added: llvm/trunk/unittests/Linker/CMakeLists.txt
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Linker/CMakeLists.txt?rev=194218&view=auto
> ==============================================================================
> --- llvm/trunk/unittests/Linker/CMakeLists.txt (added)
> +++ llvm/trunk/unittests/Linker/CMakeLists.txt Thu Nov  7 14:14:51 2013
> @@ -0,0 +1,12 @@
> +set(LLVM_LINK_COMPONENTS
> +  core
> +  linker
> +  )
> +
> +set(LinkerSources
> +  LinkModulesTest.cpp
> +  )
> +
> +add_llvm_unittest(LinkerTests
> +  ${LinkerSources}
> +  )
> 
> Added: llvm/trunk/unittests/Linker/LinkModulesTest.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Linker/LinkModulesTest.cpp?rev=194218&view=auto
> ==============================================================================
> --- llvm/trunk/unittests/Linker/LinkModulesTest.cpp (added)
> +++ llvm/trunk/unittests/Linker/LinkModulesTest.cpp Thu Nov  7 14:14:51 2013
> @@ -0,0 +1,131 @@
> +//===- llvm/unittest/Linker/LinkModulesTest.cpp - IRBuilder tests ---------===//
> +//
> +//                     The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#include "llvm/Linker.h"
> +#include "llvm/IR/IRBuilder.h"
> +#include "llvm/IR/BasicBlock.h"
> +#include "llvm/IR/DataLayout.h"
> +#include "llvm/IR/Function.h"
> +#include "llvm/IR/Module.h"
> +#include "gtest/gtest.h"
> +
> +using namespace llvm;
> +
> +namespace {
> +
> +class LinkModuleTest : public testing::Test {
> +protected:
> +  virtual void SetUp() {
> +    LLVMContext &Ctx = getGlobalContext();
> +    M.reset(new Module("MyModule", Ctx));
> +    FunctionType *FTy = FunctionType::get(Type::getInt8PtrTy(Ctx),
> +                                          Type::getInt32Ty(Ctx),
> +                                          false /*=isVarArg*/);
> +    F = Function::Create(FTy, Function::ExternalLinkage, "ba_func", M.get());
> +    F->setCallingConv(CallingConv::C);
> +
> +    EntryBB = BasicBlock::Create(Ctx, "entry", F);
> +    SwitchCase1BB = BasicBlock::Create(Ctx, "switch.case.1", F);
> +    SwitchCase2BB = BasicBlock::Create(Ctx, "switch.case.2", F);
> +    ExitBB = BasicBlock::Create(Ctx, "exit", F);
> +
> +    ArrayType *AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
> +
> +    GV = new GlobalVariable(*M.get(), AT, false /*=isConstant*/,
> +                            GlobalValue::InternalLinkage,
> +                            0, "switch.bas");
> +
> +
> +    // Global Initializer
> +    std::vector<Constant*> Init;
> +    Constant *SwitchCase1BA = BlockAddress::get(SwitchCase1BB);
> +    Init.push_back(SwitchCase1BA);
> +
> +    Constant *SwitchCase2BA = BlockAddress::get(SwitchCase2BB);
> +    Init.push_back(SwitchCase2BA);
> +
> +    ConstantInt *One = ConstantInt::get(Type::getInt32Ty(Ctx), 1);
> +    Constant *OnePtr = ConstantExpr::getCast(Instruction::IntToPtr,
> +                                             One, Type::getInt8PtrTy(Ctx));
> +    Init.push_back(OnePtr);
> +
> +    GV->setInitializer(ConstantArray::get(AT, Init));
> +  }
> +
> +  virtual void TearDown() {
> +    M.reset();
> +  }
> +
> +  OwningPtr<Module> M;
> +  Function *F;
> +  GlobalVariable *GV;
> +  BasicBlock *EntryBB;
> +  BasicBlock *SwitchCase1BB;
> +  BasicBlock *SwitchCase2BB;
> +  BasicBlock *ExitBB;
> +};
> +
> +TEST_F(LinkModuleTest, BlockAddress) {
> +  LLVMContext &Ctx = getGlobalContext();
> +  IRBuilder<> Builder(EntryBB);
> +
> +  std::vector<Value*> GEPIndices;
> +  GEPIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ctx), 0));
> +  GEPIndices.push_back(F->arg_begin());
> +
> +  Value *GEP = Builder.CreateGEP(GV, GEPIndices, "switch.gep");
> +  Value *Load = Builder.CreateLoad(GEP, "switch.load");
> +
> +  Builder.CreateRet(Load);
> +
> +  Builder.SetInsertPoint(SwitchCase1BB);
> +  Builder.CreateBr(ExitBB);
> +
> +  Builder.SetInsertPoint(SwitchCase2BB);
> +  Builder.CreateBr(ExitBB);
> +
> +  Builder.SetInsertPoint(ExitBB);
> +  Builder.CreateRet(ConstantPointerNull::get(Type::getInt8PtrTy(Ctx)));
> +
> +  Module *LinkedModule = new Module("MyModuleLinked", getGlobalContext());
> +  Linker::LinkModules(LinkedModule, M.get(), Linker::PreserveSource, 0);
> +
> +  // Delete the original module.
> +  M.reset();
> +
> +  // Check that the global "@switch.bas" is well-formed.
> +  const GlobalVariable *LinkedGV = LinkedModule->getNamedGlobal("switch.bas");
> +  const Constant *Init = LinkedGV->getInitializer();
> +
> +  // @switch.bas = internal global [3 x i8*]
> +  //   [i8* blockaddress(@ba_func, %switch.case.1),
> +  //    i8* blockaddress(@ba_func, %switch.case.2),
> +  //    i8* inttoptr (i32 1 to i8*)]
> +
> +  ArrayType *AT = ArrayType::get(Type::getInt8PtrTy(Ctx), 3);
> +  EXPECT_EQ(AT, Init->getType());
> +
> +  Value *Elem = Init->getOperand(0);
> +  ASSERT_TRUE(isa<BlockAddress>(Elem));
> +  EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
> +            LinkedModule->getFunction("ba_func"));
> +  EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
> +            LinkedModule->getFunction("ba_func"));
> +  
> +  Elem = Init->getOperand(1);
> +  ASSERT_TRUE(isa<BlockAddress>(Elem));
> +  EXPECT_EQ(cast<BlockAddress>(Elem)->getFunction(),
> +            LinkedModule->getFunction("ba_func"));
> +  EXPECT_EQ(cast<BlockAddress>(Elem)->getBasicBlock()->getParent(),
> +            LinkedModule->getFunction("ba_func"));
> +
> +  delete LinkedModule;
> +}
> +
> +} // end anonymous namespace
> 
> Copied: llvm/trunk/unittests/Linker/Makefile (from r194205, llvm/trunk/unittests/Makefile)
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Linker/Makefile?p2=llvm/trunk/unittests/Linker/Makefile&p1=llvm/trunk/unittests/Makefile&r1=194205&r2=194218&rev=194218&view=diff
> ==============================================================================
> --- llvm/trunk/unittests/Makefile (original)
> +++ llvm/trunk/unittests/Linker/Makefile Thu Nov  7 14:14:51 2013
> @@ -1,4 +1,4 @@
> -##===- unittests/Makefile ----------------------------------*- Makefile -*-===##
> +##===- unittests/Linker/Makefile ---------------------------*- Makefile -*-===##
> #
> #                     The LLVM Compiler Infrastructure
> #
> @@ -7,12 +7,9 @@
> #
> ##===----------------------------------------------------------------------===##
> 
> -LEVEL = ..
> +LEVEL = ../..
> +TESTNAME = Linker
> +LINK_COMPONENTS := core linker
> 
> -PARALLEL_DIRS = ADT Analysis Bitcode CodeGen DebugInfo ExecutionEngine IR \
> -		MC Object Option Support Transforms
> -
> -include $(LEVEL)/Makefile.common
> -
> -clean::
> -	$(Verb) $(RM) -f *Tests
> +include $(LEVEL)/Makefile.config
> +include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest
> 
> Modified: llvm/trunk/unittests/Makefile
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Makefile?rev=194218&r1=194217&r2=194218&view=diff
> ==============================================================================
> --- llvm/trunk/unittests/Makefile (original)
> +++ llvm/trunk/unittests/Makefile Thu Nov  7 14:14:51 2013
> @@ -10,7 +10,7 @@
> LEVEL = ..
> 
> PARALLEL_DIRS = ADT Analysis Bitcode CodeGen DebugInfo ExecutionEngine IR \
> -		MC Object Option Support Transforms
> +		Linker MC Object Option Support Transforms
> 
> include $(LEVEL)/Makefile.common
> 
> 
> 
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